Abstract!of!thesis!entitled! - HKU Nursing Hoi Ching.pdf · Abstract!of!thesis!entitled!! “An...
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Abstract of thesis entitled
“An evidence-based guideline of preoperative forced-air warming
in reducing inadvertent perioperative hypothermia
for patients undergoing general anesthesia”
Submitted by
Wong Hoi Ching
For the degree of Master of Nursing
at The University of Hong Kong
in July 2016
Inadvertent perioperative hypothermia (IPH) is a common problem for
patients undergoing general anesthesia (GA), which could lead to many detrimental
physiologic alternations and increase morbidity. A core body temperature of less than
36ºC in the perioperative period without deliberate planning is defined as IPH. It
might increase the incidence of complications including coagulopathy, postoperative
shivering, surgical site infection and healing problem. Studies have shown that
preoperative forced-air warming before GA helps prevent IPH mostly. In this thesis,
six studies about the innovation of preoperative forced-air warming to reduce IPH are
systematically reviewed and appraised critically. The results of the selected studies
are summarized and synthesized so as to develop an evidence-based guideline of the
use of preoperative forced-air warming for patient undergoing GA. In order to adopt
the guideline in the local clinical setting, the implementation potential of the proposed
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guideline including the transferability, feasibility and the cost-benefit ratio were
assessed. An implementation plan including communication process, pilot study plan
and evaluation plan were established in order to promote a smooth implementation of
the innovation. It is aimed that the introduction of the innovation can help to reduce
IPH and its subsequent complication so to improve patient safety and surgical
outcomes.
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An evidence-based guideline of preoperative forced-air warming
in reducing inadvertent perioperative hypothermia
for patients undergoing general anesthesia
by
Wong Hoi Ching
BNurs (Hons) H.K.U., R.N.
A thesis submitted in partial fulfillment of the requirements for
The Degree of Master of Nursing
at The University of Hong Kong
July 2016
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Declaration
I declare that this thesis represents my own work, except where due
acknowledgement is made, and that is has not been previously included in a thesis,
dissertation or report submitted to this University or to any other institution for a
degree, diploma or other qualifications.
Signed ___________________________________________
Wong Hoi Ching
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Acknowledgements
I would like to express my sincere gratitude to my dissertation supervisor, Dr.
Veronica Lam for her considerate understanding, guidance, encouragement, and
expert advices throughout the dissertation journey. She is very supportive and helpful.
It is my great pleasure to have Dr. Lam being the supervisor in my master course
study in The University of Hong Kong.
I would also like to thank my colleagues, friends and classmates for their
support and help during these two years of study.
Last but not the least, I have to thank my family and my husband for their
caring and support.
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Table of Contents
Abstract ......................................................................................................................... i
Declaration .................................................................................................................. iv Acknowledgements ...................................................................................................... v
Table of Contents ........................................................................................................ vi List of Appendixes ...................................................................................................... ix
Abbreviations ............................................................................................................... x CHAPTER 1: INTRODUCTION .............................................................................. 1
Background -------------------------------------------------------------------------------------------- 1
Affirming Need ---------------------------------------------------------------------------------------- 2
Significance -------------------------------------------------------------------------------------------- 4
Objectives ---------------------------------------------------------------------------------------------- 6
Research Question ------------------------------------------------------------------------------------ 7
PICO ---------------------------------------------------------------------------------------------------- 7
CHAPTER 2: CRITICAL APPRAISAL .................................................................. 8
Search Strategy --------------------------------------------------------------------------------------- 8
Inclusion Criteria ------------------------------------------------------------------------------------- 8
Exclusion Criteria ------------------------------------------------------------------------------------ 9
Appraisal Strategy ------------------------------------------------------------------------------------ 9
Search Results ----------------------------------------------------------------------------------------- 9
Data Extraction ------------------------------------------------------------------------------------- 10
Quality Assessment --------------------------------------------------------------------------------- 10
Research question ............................................................................................................ 11 Randomization method ................................................................................................... 11 Concealment method ....................................................................................................... 11 Blinding method .............................................................................................................. 12 Group’s similarity ........................................................................................................... 12 Study’s intervention ........................................................................................................ 13 Outcome measurement .................................................................................................... 13 Dropout rate ..................................................................................................................... 13 Intention to treat analysis ................................................................................................ 14 Generalizability ............................................................................................................... 14
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Bias .................................................................................................................................. 14 Effectiveness and applicability ........................................................................................ 15
Summary --------------------------------------------------------------------------------------------- 15
Country of study .............................................................................................................. 15 Sample size ...................................................................................................................... 16 Patient’s characteristics ................................................................................................... 16 Type of surgery ............................................................................................................... 17 Intervention ..................................................................................................................... 17 Control ............................................................................................................................. 18 Outcome measures .......................................................................................................... 18 Results ............................................................................................................................. 19
Synthesis ---------------------------------------------------------------------------------------------- 20
Target population ............................................................................................................ 20 Intervention ..................................................................................................................... 20 Outcomes ......................................................................................................................... 21
Conclusion ------------------------------------------------------------------------------------------- 21
CHAPTER 3: IMPLEMENTATION POTENTIAL AND CLINICAL GUIDELINE .............................................................................................................. 22
Transferability of Findings ----------------------------------------------------------------------- 22
Target setting ................................................................................................................... 22 Target population ............................................................................................................ 23 Philosophy of care ........................................................................................................... 23 Sufficiency of patients being benefited ........................................................................... 24 Time for implementation and evaluation ........................................................................ 24
Feasibility -------------------------------------------------------------------------------------------- 25
Freedom to try ................................................................................................................. 25 Interference on current staff function .............................................................................. 25 Support from the administration and organization .......................................................... 26 Equipment and facilities .................................................................................................. 27
Cost-Benefit Ratio ---------------------------------------------------------------------------------- 27
Potential risks of the innovation ...................................................................................... 28 Potential benefit of the innovation .................................................................................. 28 Risks of maintaining current practice .............................................................................. 29 Material costs of implementing the innovation ............................................................... 29 Nonmaterial benefit of implementing the innovation ..................................................... 30
Evidence-Based Practice Guideline ------------------------------------------------------------- 31
CHAPTER 4: IMPLEMENTATION PLAN .......................................................... 32
Communication Plan ------------------------------------------------------------------------------- 32
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Identifying the Stakeholders ............................................................................................ 32 Communication Process .................................................................................................. 33
Pilot Study Plan ------------------------------------------------------------------------------------- 36
Timeframe ....................................................................................................................... 36 Implementation Plan ....................................................................................................... 37 Evaluation Plan of Pilot Study ........................................................................................ 38
Evaluation Plan ------------------------------------------------------------------------------------- 38
Outcomes ......................................................................................................................... 39 Timeframe ....................................................................................................................... 39 Client ............................................................................................................................... 40 Data Analysis .................................................................................................................. 41
Basis for Implementation ------------------------------------------------------------------------- 41
Conclusion .................................................................................................................. 42 Appendixes ................................................................................................................. 43
Appendix I - PRISMA 2009 Flow Diagram --------------------------------------------------- 43
Appendix II - Table of Evidence ----------------------------------------------------------------- 44
Appendix III - Summary of Appraisal Results ----------------------------------------------- 47
Appendix IV - Summary of Costs of the Implementation of the Innovation ----------- 49
Appendix V - Evidence-Based Practice Guideline ------------------------------------------- 50
Appendix VI - Key to Evidence Statements and Grades of Recommendations -------- 55
Appendix VII - Questionnaire on Preoperative Forced-air Warming Application for
Nurses ----------------------------------------------------------------------------- 56
Appendix VIII - Timeframe of the Implementation and Evaluation of the Innovation
------------------------------------------------------------------------------------- 58
References .................................................................................................................. 59
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List of Appendixes
Appendix I PRISMA 2009 Flow Diagram
Appendix II Table of Evidence
Appendix III Summary of Appraisal Results
Appendix IV Summary of Costs of Implementation of the Innovation
Appendix V Evidence-Based Practice Guideline
Appendix VI Key to Evidence Statements and Grades of Recommendations
Appendix VII Questionnaire on Preoperative Forced-air Warming Application
for Nurses
Appendix VIII Timeframe of the Implementation and Evaluation of the
Innovation
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Abbreviations
APN Advanced Practiced Nurse
ASA American Society of Anesthesiologists physical status classification
System
BMI Body Mass Index
DOM Department Operations Manager
ENT Ear, Nose & Throat
GA General Anesthesia
HKWC Hong Kong West Cluster
IPH Inadvertent Perioperative Hypothermia
OT Operating Theatre
PACU Post-Anesthesia Care Unit
RCT Randomized Controlled Trial
RN Registered Nurse
SD Standard Deviation
SIGN The Scottish Intercollegiate Guideline Network
WM Ward Manager
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CHAPTER 1: INTRODUCTION
Background
Inadvertent perioperative hypothermia (IPH) is common in patients
undergoing general anesthesia. A core body temperature of less than 36ºC in the
perioperative period, which is not resulted from deliberate planning, is defined as
inadvertent perioperative hypothermia. Core body temperature can be measured in the
pulmonary artery by invasive temperature measurement through the insertion of a
pulmonary artery catheter. For noninvasive core body temperature measurement, the
tympanic, esophageal, and nasopharyngeal temperature are also regarded as reliable
measurements. All these methods can provide a continuous temperature monitoring
during surgery.
Due to the cold environment in the operation theatre, convective heat loss
from the large exposed body surface area is one of the contributing factors for the
development of hypothermia. Besides, the large opened body cavity, use of cold
intravenous solutions and blood products during surgery also contribute to
hypothermia (Charles et al., 1998). Sessler (2000) stated that the intraoperative
hypothermia composes of a three-phase pattern (cited in Shin et al., 2015). During the
first hour of general anesthesia, there would be a rapid decrease in the core body
temperature due to the anesthetic-induced impairment of thermoregulation. This leads
to the inhibition of thermoregulatory vasoconstriction with resultant core-to-
peripheral thermal redistribution due to peripheral vasodilatation induced by
anesthetic drugs. The subsequent two to three hours would be a relatively slow and
linear decrease in the body temperature results from the thermal imbalance, in which
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the heat loss exceeds the metabolic heat production. The reduction in metabolic heat
production is also an effect of anesthesia. In the third phase, the core body
temperature reaches a plateau that remains constant even for prolonged surgery due to
vasoconstriction induced by low body temperature. Certain populations are at higher
risk of developing hypothermia induced by the effect of anesthesia such as the elderly
patients and those with combined medical problems are more susceptible groups of
patients (Erdling & Johansson, 2015).
The consequences of hypothermia could lead to many detrimental physiologic
alterations and increase morbidity. Complications include decrease metabolic rate,
decrease cardiac output, metabolic acidosis, healing problems, postoperative shivering,
coagulation and platelet function abnormalities, surgical site infection, pressure ulcer
incidence levels and extended post-anesthetic recovery (Kumar, Wong, Melling, &
Leaper, 2005; Scott & Buckland, 2006). In addition, thermal discomfort reduces
patient satisfaction with surgical anesthesia (Kurz, 2008) and increase anxiety.
Therefore, patients’ perioperative body temperature should be maintained to prevent
the complications of hypothermia and to lower the costs of health service.
Affirming Need
The operating theatre nurse where I work has fifteen operation theatres. There
are averagely over 400 elective surgeries per month. Many of the surgeries are
ultramajor or major types that require for more than three to four hours operation time.
Some cases even last for more than eight hours. In the routine daily care, we provide
warm blanket to patients after admission to the operation theatre. During the
intraoperative period, the infusion fluids and blood products are warmed. Warming
mattress and/or forced-air warming blanket are provided to prevent hypothermia.
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Nasopharyngeal and rectal temperature measurements are commonly used for
continuous core temperature monitoring. The theatre temperature was set to be around
20-22°C. However, from my observation, there are still more than half of the patients
experience hypothermia either intraoperative or on admission to the post-anesthesia
care unit (PACU). Those hypothermic patients are more likely to develop
hyperventilation, shivering and higher anxiety level (Hooven, 2011). This results in a
lengthy recovery stay to resume normothermia of the patients and hence increase
healthcare’s workload and decrease turnover ability of the recovery rooms. For some
neurosurgical and trauma patients, it requires an extra stay in the operation theatre
after the operation finished to warm up the patients to an acceptable temperature
before discharge to the recovery room or ward. It is also observed that hypothermic
patients required longer time to be reversed from general anesthesia. As the elective
surgery schedule is very tight in public hospital, the overtime of surgery may lead to
cancellation of scheduled cases. This on the other hand prolongs the surgery waiting
list and increase hospital cost as well.
Some studies recommend that prewarming of patients for about 10 to 20
minutes before general anesthesia mostly prevent perioperative hypothermia
(Andrzejowski, Hoyle, Eapen & Turnbull, 2008; Horn et al., 2012). Prewarming is
defined as actively warm the patients by forced-air warming device before anesthesia
starts. It helps to reduce the core-to-peripheral temperature gradient and increases the
total body heat content (Sessler, 2001). Intraoperative warming by thermal mattress
and forced-air warming device prevents patient’s heat loss from exceeding the heat
production intraoperative (Röder et al., 2011). However, without prewarming, these
measures fail to prevent the core temperature decrease during the first hour of general
anesthesia when redistribution hypothermia occurs (Ihn et al., 2008).
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In our current clinical setting, prewarming is not a usual practice. There is
inconsistency in the knowledge of the effectiveness of prewarming before general
anesthesia to prevent perioperative hypothermia among the operative nurses. Some of
the nurses assumed that prewarming a patient before surgery would have a positive
effect on patient’s postoperative temperature while others felt that the efficacy of
prewarming is questionable and intraoperative warming is adequate to maintain
normothermia. Therefore to review the updated studies on the effect of preoperative
forced-air warming on perioperative hypothermia for patients undergoing general
anesthesia so as to promote an evidence-based practice for the operating theatre
nurses is necessary.
Previous systematic reviews have been done. The one done by Cheng, 2013
was mainly focus on the effect of prewarming on postoperative hypothermia.
However the intraoperative hypothermia is also significant for the change in
hemodynamics, coagulopathy and surgical site infection, etc. Besides, there is lack of
consensus in prewarming times, warming device and warming methods in previous
studies. At the same time, there is new evidence derived from updated studies that
have not been reviewed. Therefore, I would like to review the effect of preoperative
forced-air warming in reducing inadvertent perioperative hypothermia for patients
undergoing general anesthesia and develop evidence-based practice guideline to
integrate the updated evidence into our daily practice.
Significance
Patients undergoing general anesthesia are vulnerable to a perioperative
decrease in core temperature leading to inadvertent perioperative hypothermia. Study
suggested that 50% to 70% of all surgical patients experience IPH (Frank, Shir, Raja,
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Fleisher & Beattie, 1994). It is one of the perioperative nurse's’ roles to optimize
patient care practices to maintain normothermia and prevent perioperative
hypothermia. As mentioned, hypothermia could leads to many complications. Several
randomized controlled trials noted that hypothermia increases the rate of infection
(Andrzejowski et al., 2008; Erdling & Johansson, 2015; Shin et al., 2015). Kurz,
Sessler, and Lenhardt (1996) found that a mean intraoperative core temperature (±
standard deviation [SD]) of 35.7°C ± 0.6°C had a 13% increased risk of infection
compared with a normothermic body temperature. Additionally, hypothermia has
been found to affect the pharmacokinetics of anesthetic medications and blood loss
during surgery, and to alter physico-biological dynamics (Hooven, 2011). Leslie,
Sessler, Bjorksten, and Moayeri (1995) found that propofol concentrations averaged
28% more at 34°C than at 37°C. It has been noted that the duration of the action of
muscle relaxants such as atracurium and vecuronium would be significantly
prolonged in the hypothermic groups (Leslie et al., 1995). A meta-analysis completed
by Rajagopalan, Mascha, Na, and Sessler (2008) concluded that hypothermia
significantly increases blood loss by approximately 16% and increases the risk of a
blood transfusion by approximately 22%. Hypothermia has also been noted to
increase hospital costs (Mahoney & Odom, 1999). Because normothermic patients
were found to have less adverse outcomes compared with hypothermic patients,
hospital-associated costs were less (Mahoney & Odom, 1999). Increased PACU
length of stay and increased hospital stay were also associated with hypothermia in
the perioperative setting (Andrzejowski et al., 2008). Various healthcare institutions
have published clinical guidelines across the country advocating the importance of
maintaining normothermia in the perioperative setting. In its guideline for preventing
surgical site infection, the Centers for Disease Control and Prevention noted that
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preventing hypothermia reduces the risk of infection. In addition, the American
Society of Anesthesiologists recommends in its practice guidelines that normothermia
should be a goal during emergence and recovery from anesthesia. Moreover,
minimizing hypothermia in the perioperative setting can promote optimal health for
patients. Understanding hypothermia, its complications and effective prevention
measures in the perioperative period is significant for nurses who want to apply
evidence-based practice in clinical practice. It is also essential to plan effective
interventions that minimize or make it possible to prevent complications arising from
surgical anesthesia, with a view to patient safety, which is the main goal of
perioperative nursing.
Objectives
1) To perform systematic literature review on the effectiveness of pre-operative
forced-air warming in reducing inadvertent perioperative hypothermia for
patients undergoing general anesthesia.
2) To appraise the chosen studies critically, then summarize and synthesize the
results from the chosen studies.
3) To develop an evidence-based guideline of the use of preoperative forced-air
warming for patient undergoing general anesthesia.
4) To assess the implementation potential of the proposed guidelines in local
clinical setting.
5) To develop implementation and evaluation plans fro the proposed guidelines.
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Research Question
Is preoperative forced-air warming effective in reducing inadvertent perioperative
hypothermia for patients undergoing general anesthesia?
PICO
Under the PICO framework, the population (P) is adult patients undergoing general
anesthesia. The Intervention (I) is preoperative forced-air warming before induction
of anesthesia for a certain period of time. The comparison (C) is current warming
method without preoperative forced-air warming. The Outcome (O) is to reduce the
incidence of inadvertent perioperative hypothermia.
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CHAPTER 2: CRITICAL APPRAISAL
Search Strategy
A systematic literature searching was performed from August 2015 to
November 2015 through electronic databases, which includes Pubmed and Cochrane
Library. The keywords used were separated into two groups. “Prewarming”,
“preoperative warming” and “preoperative forced-air warming” are in one group
while “hypothermia” and “perioperative hypothermia” are in another group. The
keywords were searched separately and by using “or” within groups and using “and”
between groups in both databases. The same sets of keywords were used for searching
in Google Scholar Engine. A PRISMA flow diagram was used to structure the
literature searching and screening for selecting appropriate articles that are relevant to
the research question. Inclusion and exclusion criteria were used to narrow down the
number of searched articles. After that, a manual searching of the reference list of
chosen studies was performed to prevent any missing of eligible literatures. Searching
for relevant literature reviews have also been done to check for any updated reviews
and identified the need of this guideline.
Inclusion Criteria
1. Adult patients ≥ 18 years old
2. Preoperative forced-air warming was used as an intervention
3. The incidence of perioperative hypothermia or the change in core temperature
is included in the outcome measures
4. Randomized controlled trial (RCT) studies
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5. Articles published from 2005 to 2015
6. Written in English
7. Full text of articles is available
Exclusion Criteria
1. Patients undergoing regional anesthesia without general anesthesia
2. Use of other prewaming methods as the intervention
Appraisal Strategy
The Scottish Intercollegiate Guideline Network (SIGN) (2015) Methodology
Checklist 2 for controlled trials was used as a tool to critically appraise the internal
validity and the overall quality assessment of the selected studies. The results are
summarized in Appendix III, whereas the details are mentioned in the following
quality assessment.
Search Results
Under the criteria of randomized controlled trial studies published from 2005
to 2015 and written in English, the search results from the two electronic databases
are as follows. By using the keywords of “prewarming” OR “preoperative warming”
OR “preoperative forced air warming”, 28 articles in Pubmed and 81 articles in
Cochrane Library were found. By using the keywords of “hypothermia” OR
“perioperative hypothermia”, 475 articles in Pubmed and 973 articles in Cochrane
Library were found. By combining the two groups of keywords using “AND” for
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searching, 15 articles in Pubmed and 32 articles in Cochrane Library were found. The
same sets of keywords were searched in Google Scholar Engine and 24 articles were
found. After checking for duplication, 39 articles were removed. Abstract screening
of the 32 articles left for the criteria of patients under general anesthesia and taking
preoperative forced-air warming as an intervention, 23 articles are removed for
irrelevance. Among the 9 remaining articles, 2 articles were removed due to full text
not available. 1 article was removed, as the study was not comparing the intervention
with control group, instead comparing two protocols of interventions. The 6
remaining full-text articles were assessed to be eligible for the review. The search
results were summarized in the PRISMA flow diagram shown in Appendix I.
Data Extraction
The 6 selected articles were reviewed in details. Data was extracted, integrated
and summarized in a table of evidence shown in Appendix II. The table of evidence
consisted of type of study design, patient’s characteristic, study intervention,
comparison, outcome measures, measuring tools, site and time interval for body
temperature, and results. Details were shown in the table of evidence.
Quality Assessment
The 6 selected articles were appraised under the following aspects under the
SIGN methodology checklist for controlled trials.
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Research question
All the studies have addressed an appropriate and clearly focused question
with identified population, intervention, comparison and outcomes (Andrzejowski et
al., 2008; Erdling & Johansson, 2015; Fettes, Mulvaine, & Doren, 2013; Horn et al.,
2012; Kim et al., 2006; Shin et al., 2015).
Randomization method
For the study design, four of the studies used parallel-group RCT design
(Andrzejowski et al., 2008; Erdling & Johansson, 2015; Horn et al., 2012; Kim et al.,
2006). One used prospective pretest/posttest design (Fettes et al., 2013), while another
one used consecutive prospective design (Shin et al., 2015).
Three of the studies mentioned the randomization methods. One used
computer-generated randomization (Andrzejowski et al., 2008), another one used the
last two digits of patients account number and random integers for randomization
(Fettes et al., 2013), while the third one randomized by rolling a modified dice with
four faces representing four treatment groups (Horn et al., 2012). The other three
studies have mentioned about random assignment but have not specified the method
used (Erdling & Johansson, 2015; Kim et al., 2006; Shin et al., 2015).
Concealment method
Four of the studies used the sealed envelope technique for concealment
(Erdling & Johansson, 2015; Fettes et al., 2013; Kim et al., 2006; Shin et al., 2015),
while the other two studies have not addressed the concealment methods
(Andrzejowski et al., 2008; Horn et al, 2012).
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Blinding method
Blinding to the subjects was not used in all the studies and the patients could
be easily noted for the provision of intervention, thus blinding was not applicable
(Andrzejowski et al., 2008; Erdling & Johansson, 2015; Fettes et al., 2013; Horn et
al., 2012; Kim et al., 2006; Shin et al., 2015). In Fettes et al., (2013)’s study, the
PACU nurses performing the postoperative temperature measurement were blinded to
patient’s group assignment. In Horn et al. (2012)’s study, the anesthetist providing
general anesthesia was blinded to the prewarming randomization and the investigator
in PACU grading patient’s shivering was blinded to patient’s core temperature and
the group assignment. Other four studies have not mentioned about any blinding to
the investigators intraoperative and postoperative (Andrzejowski et al., 2008; Erdling
& Johansson, 2015; Kim et al., 206; Shin et al., 2015).
Group’s similarity
There was no significant difference between the intervention and control
groups for patient’s characteristics, types and duration of surgery, theatre room
temperature, and anesthetic technique in five studies (Andrzejowski et al., 2008;
Erdling & Johansson, 2015; Fettes et al., 2013; Horn et al., 2012; Kim et al., 2006;
Shin et al., 2015). As the impact of age and body mass index on core temperature was
also investigated in Erdling and Johansson (2015)’s study, these two patient’s
characteristics may differ between groups while the others variables were similar.
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Study’s intervention
In five studies done by Andrzejowski et al. (2008), Erdling and Johansson
(2015), Fettes et al. (2013), Kim et al. (2006), and Shin et al. (2015), preoperative
forced air warming was the only difference between the intervention and control
groups. The study done by Horn et al. (2012) consisted of three intervention groups
with different duration of prewarming period. It aimed to investigate the effect of
short time periods of prewarming on the prevention of perioperative hypothermia.
Therefore the prewarming duration between groups was different.
Outcome measurement
All studies used valid and reliable measuring tools for the outcome
measurement (Andrzejowski et al., 2008; Erdling & Johansson, 2015; Fettes et al.,
2013; Horn et al., 2012; Kim et al., 2006; Shin et al., 2015). Esophageal and
nasopharyngeal temperature probes, temporal artery scanner, tympanic temperature
sensor and pulmonary artery catheter were used in the studies for measuring the core
temperature, in which all are valid and reliable. Some studies used more than one of
the above measuring tools (Andrzejowski et al., 2008; Erdling & Johansson, 2015;
Shin et al., 2015).
Dropout rate
Four studies done by Andrzejowski et al. (2008), Horn et al. (2012), Kim et al.
(2006), and Shin et al. (2015) reported 0% dropout rate. The other two studies done
by Erdling and Johansson (2015), and Fettes et al. (2013) reported 17% and 12%
dropout rate respectively. According to the notes on the use of SIGN methodology
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checklist for randomized controlled trials, a dropout rate of less than 20% is regarded
as acceptable (SIGN, 2015).
Intention to treat analysis
Four studies done by Andrzejowski et al. (2008), Horn et al. (2012), Kim et al.
(2006), and Shin et al. (2015) have analysed the patients in the groups they were
randomly allocated. Studies done by Erdling and Johansson (2015), and Fettes et al.
(2013) only analysed the patients who completed the studies and based on patients
whom the outcome measures were obtained. In Fettes et al. (2013)’s study, five
patients in the intervention group withdrew before or shortly after the intervention due
to uncomfortable warming. The data of these patients was not included in the final
results analysis.
Generalizability
All the studies were carried out at one site (Andrzejowski et al., 2008; Erdling
& Johansson, 2015; Fettes et al., 2013; Horn et al., 2012; Kim et al., 2006; Shin et al.,
2015). Therefore the generalizability is limited.
Bias
According to the coding system of SIGN (2015), the quality of the studies in
minimizing bias can be rated as (++), (+), (-) and 0, which representing high quality,
acceptable, low quality and unacceptable respectively. Among the six studies, four are
rated as (++) as good randomization and group allocation concealment has been
achieved (Andrzejowski et al., 2008; Horn et al., 2012; Kim et al., 2006; Shin et al.,
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2015). Study done by Erdling and Johansson (2015) is rated as (+) since the
concealment method was not mentioned. Fettes et al. (2013)’s study is rated as (-)
since the concealment method was not mentioned, not all the patients were analysed
in the groups that they were randomly allocated and increased attention has place on
intraoperative care to minimize heat loss on the need to keep patients warm.
Effectiveness and applicability
All the studied have taken the statistical power to be 80% and a significance
level of 5% for data analysis except the study of Kim et al. (2006), in which the
statistical power was not mentioned (Andrzejowski et al., 2008; Erdling & Johansson,
2015; Fettes et al., 2013; Horn et al., 2012; Shin et al., 2015). After evaluation of the
methodology used and the power of the studies, it is quite certain that the overall
effect of most of the selected studies is due to the prewarming intervention except
Fettes et al. (2013)’s study. Due to the difference in the group sample size, the
statistical outcome might be affected. The results of all the studies are directly
applicable to the target population in this guideline (Andrzejowski et al., 2008;
Erdling & Johansson, 2015; Fettes et al., 2013; Horn et al., 2012; Kim et al., 2006;
Shin et al., 2015).
Summary
Country of study
The studies were carried out in United Kingdom, Sweden, American,
Germany, and two from South Korea (Andrzejowski et al., 2008; Erdling &
16
Johansson, 2015; Fettes et al., 2013; Horn et al., 2012; Kim et al., 2006; Shin et al.,
2015).
Sample size
The sample size of the studies ranged from 40 subjects (Kim et al., 2006) to
128 subjects (Fettes et al., 2013).
Patient’s characteristics
All studies include adult patients undergoing general anesthesia as the
subjects. Four studies included patients with American Society of Anesthesiologists
physical status classification system (ASA) < 3 only (Andrzejowski et al., 2008;
Erdling & Johansson, 2015; Fettes et al., 2013; Horn et al., 2012), while the other two
studies did not mention the ASA status (Kim et al., 2006; Shin et al., 2015). Exclusion
criteria include peripheral vascular disease, history of fever, thyroid disease, unable to
understand information and give consent were used in three studies (Erdling &
Johansson, 2015; Fettes et al., 2013; Kim et al 2006; Shin et al., 2015). Patients with
neurological disease and known infection were excluded in two studies (Fettes et al.,
2013; Kim et al 2006; Shin et al., 2015). Erdling and Johansson (2015) excluded
patients with nasal or esophageal anomalies. Fettes et al. (2013) excluded patients
with autonomic dysfunctions, Cushing syndrome and with admission temperature
higher than 37.5 or less than 36.5. Kim et al. (2006) excluded patients with any skin
lesion, history of hypersensitivity to skin contact device, having reduced left
ventricular function and single coronary artery disease. Shin et al. (2015) exclude
patients with body mass index (BMI) exceeding 35 kg/m2 and preoperative body
17
temperature more that 37.2°C. Exclusion criteria was not mentioned in Andrzejowski
et al. (2008)’s study.
Type of surgery
Three studies recruited patients from scheduled surgeries, which includes
spinal surgery, colorectal surgery, general surgery, minor orthopedic surgeries and
ENT surgery (Andrzejowski et al., 2008; Erdling & Johansson, 2015; Horn et al.,
2012). Shin et al. (2015) included patients undergoing endovascular coiling to treat
cerebral aneurysm from both scheduled and emergency cases. Fettes et al. (2013)
recruited patients from various types of surgery while Kim et al. (2006) recruited
patients undergoing Off-pump coronary artery bypass surgery. Both haven’t
mentioned about whether the surgery was under scheduled only or included
emergency. The duration of surgery ranged from 40 min (Andrzejowski et al., 2008)
to over 210 min (Erdling & Johansson, 2015). The surgery duration was not
mentioned in Fettes et al. (2013)’s study.
Intervention
All the studied used forced-air warming blanket for preoperative warming
with the temperature setting ranged from 37.8°C (Fettes et al., 2013) to 44°C (Horn et
al., 2012). The mean duration of prewarming ranged from 30 min (Shin et al., 2015)
to 72 min (Andrzejowski et al., 2008), while Horn et al. (2012) studied on three
intervention groups with difference prewarming duration 10 min, 20 min, and 30 min.
18
Control
Warm cotton blanket was used in control group in three studies (Fettes et al.,
2013; Kim et al., 2006; Shin et al., 2015). Two studies covered patients in control
group with the forced-air warming blanket without turning on (Andrzejowski et al.,
2008; Fettes et al., 2013). Other studies just mentioned about passive insulation or
without prewarming in the control group (Erdling & Johansson, 2015; Horn et al.,
2012).
Outcome measures
Four studies measured the change in mean core temperature between
intervention and control groups intraoperative (Andrzejowski et al., 2008; Erdling &
Johansson, 2015; Kim et al., 2006; Shin et al., 2015). Two studies measured the
incidence of intraoperative hypothermia (Andrzejowski et al., 2008; Shin et al., 2015).
One study measured postoperative temperature (Fettes et al., 2013), and one measured
the incidence of postoperative hypothermia (Horn et al., 2012). Three studies
measured the number of patient experienced shivering in PACU (Andrzejowski et al.,
2008; Horn et al., 2012; Shin et al., 2015). Erdling and Johansson (2015) measured
the relationship of age and BMI between esophageal temperatures, while Fettes et al.
(2013) measured the length of PACU stay. Horn et al. (2012) measured the number of
patients required active warming intraoperative and postoperative. Kim et al. (2006)
measured the hemodynamic changes between groups intraoperative and Shin et al.
(2015) measured the number of patient developed procedure-related complication.
19
Results
For the measurement of mean core temperature between pre-warmed group
and control group, all the four studies showed that the core temperature in the pre-
warmed group was significantly greater than that in the control group (Andrzejowski
et al., 2008; Erdling & Johansson, 2015; Kim et al., 2006; Shin et al., 2015). For the
incidence of intraoperative hypothermia, both studies of Andrzejowski et al. (2008)
and Shin et al. (2015) showed a statistically significant lower incidence in the pre-
warmed group than the control group. Horn et al. (2012)’s study also reported a
significant lower incidence of postoperative hypothermia, lower necessity and shorter
duration for intra- and postoperative warming in the pre-warmed groups. Fettes et al.
(2013)’s study showed no significant difference in patient’s postoperative temperature
among group. However, the outcome might be affect by the difference in group size
and the lack of patients with hypothermia in both groups. Study of Erdling and
Johansson (2015) showed a negative correlation between esophageal temperature and
age, and a significant difference between BMI and esophageal temperature. This
indicates that the elderly are more likely to develop perioperative hypothermia and the
risk is reduced in the obese. Other measuring outcomes include postoperative
shivering, length of PACU stay, hemodynamic changes and procedure-related
complication were shown to have no significant difference among the pre-warmed
and control groups.
20
Synthesis
Target population
All the studies were carried out in developing countries with similar hospital
setting to the operation rooms in my working hospital (Andrzejowski et al., 2008;
Erdling & Johansson, 2015; Fettes et al., 2013; Horn et al., 2012; Kim et al., 2006;
Shin et al., 2015). Majority of the patients studied were adults with ASA < 3
undergoing general anesthesia for elective surgery. Similar exclusion criteria were
reported from majority of the studies, which implied that our target population should
exclude those with fever, known infection, thyroid disease, peripheral vascular
disease and neurological disease.
Intervention
All the studies used forced-air warming device to provide the prewaming
intervention (Andrzejowski et al., 2008; Erdling & Johansson, 2015; Fettes et al.,
2013; Horn et al., 2012; Kim et al., 2006; Shin et al., 2015). Among the six studies,
half of them set the temperature of the forced-air warming at about 38°C, while
another half set the temperature ≥ 40°C. Since more significant results obtained from
studies with the set temperature ≥ 40°C, it implied that the temperature of the forced-
air warming device was better to be set as ≥ 40°C. Besides, majority of the studies
prewamed the patient ≥ 30 min. It implied that more than 30 min of prewaming would
be more effective to prevent perioperative redistribution hypothermia.
21
Outcomes
Majority of the studies measured patient’s mean core temperature of
intraoperative and showed significant difference between the intervention and control
group (Andrzejowski et al., 2008; Erdling & Johansson, 2015; Kim et al., 2006; Shin
et al., 2015). Half of the studies measured the incidence of hypothermia either
intraoperative or postoperative and showed significant results. Majority of the studies
showed no significant difference for other measuring outcomes. These implied that
the intraoperative mean core temperature and the incidence of hypothermia were best
to be used as the outcome measures for evaluating the effectiveness of preoperative
forced-air warming on patients undergoing general anesthesia.
Conclusion
After critical appraisal and evidence extraction from the selected articles, there
is adequate evidence in supporting the use of preoperative forced-air warming on
adult patient undergoing general anesthesia. Five out of the six studies showed
supports to the use of prewarming in reducing the decrease in mean core temperature
intraoperative and the incidence of perioperative hypothermia for patients undergoing
general anesthesia.
22
CHAPTER 3: IMPLEMENTATION POTENTIAL
AND CLINICAL GUIDELINE
The previous chapters have shown that the provision of preoperative forced-
air warming was effective in reducing inadvertent perioperative hypothermia for
patients undergoing general anesthesia (GA). In order to translate the finding into
current clinical practice, this chapter reviews the implementation potential of this
evidence-based innovation through exploring the transferability of findings, feasibility
and cost-benefit ratio.
Transferability of Findings
The transferability of findings is assessed as followed by investigating the
similarity of the research findings with the current clinical aspects, including target
setting, population, philosophy of care, sufficiency of patients being benefit from the
innovation and the time of implementation and evaluation.
Target setting
The innovation of providing preoperative forced-air warming to patient
undergoing GA will be carried out in the operating theatres with 24-hour service in a
public hospital in Hong Kong West Cluster (HKWC). From the studies reviewed, all
were carried out in developing countries, which have similar operating theatre setting
and staff workload with Hong Kong (Andrzejowski, Hoyle, Eapen & Turnbull, 2008;
Erdling & Johansson, 2015; Fettes et al., 2013; Horn et al., 2012; Kim et al., 2006;
Shin et al., 2015). The studies also covered various types of surgery, in which the
23
target operating theatres also perform various types of surgery. Thus the innovation is
transferable to be implemented in the proposed setting.
Target population
Majority of the reviewed studies included adult patients aged from 18 to 85
years old with American Society of Anesthesiologists physical status classification
system (ASA) < 3 undergoing GA (Andrzejowski et al., 2008; Erdling & Johansson,
2015; Fettes et al., 2013; Horn et al., 2012; Shin et al., 2015). In the target operating
rooms, about 75% of patients admitted for scheduled operation undergoing GA in
2015 were adults aged over 18 years old with ASA < 3 under an observational
estimation. Thus the characteristics of the target population are similar to those in the
studies.
Philosophy of care
The philosophy of care underlying the innovation which is to enhance patient
care and improve patient outcome fit the mission of the target hospital, which is “ to
care with Empathy, to serve with Expertise and Excellence”. By putting ourselves
into patient’s shoes, we empathize patient’s suffering from perioperative hypothermia
and the subsequent complications. For the excellence of care, introduction of the
innovation improves patient safety by minimizing the complications arise from
perioperative hypothermia. Besides, establishing an evidence-based guideline for the
innovation from the research findings helps to improve nursing care and enhance
nursing professionalism as well as achieving the expertise of care. As a result, the
prevailing philosophy is entrenched.
24
Sufficiency of patients being benefited
In the target hospital, there are averagely 4800 elective surgeries undergoing
general anesthesia per year, in which 3600 of them are adult patient over 18 years old
with ASA < 3 annually. As the hospital is a tertiary and quaternary referral centre for
many advanced and complex service including transplant, oral maxillofacial surgery,
reconstruction surgery and neurosurgery etc. in Hong Kong, the number of surgeries
is foresaw to be increasing. Therefore, the number of patients being benefited from
the innovation will be increased as well. It is estimated to have about 300 patients
being benefit per month.
Time for implementation and evaluation
It is estimated that the implementation and evaluation of the whole project will
take a period of 44 weeks. It will be divided into four phases including preparation,
pilot test, implementation and evaluation phases. During the preparatory phase, a
work group will be formed within the first week, which will be responsible for
planning, implementing and evaluating the whole project. 8 weeks will be reserved
for inter-departmental and interdisciplinary communication and coordination as well
as the preparation of required device and materials, guidelines and documentation
chart. 2 weeks will be taken for providing staff briefing sessions. After that, a pilot
test will commence for 6 weeks with evaluation. Subsequently, a 24-week
implementation phase will begin and followed with a 4-week evaluation phase.
25
Feasibility
The feasibility of implementing the innovation in the target setting is assessed
in the following section through different aspects.
Freedom to try
Perioperative nurses have the responsibility to ensure patients’ safety and to
minimize the risks and complications arising from general anesthesia and the surgery.
As the provision of preoperative forced-air warming requires no specific technique
and medication, nurses have the freedom to initiate, terminate and resume the
innovation according to patient’s condition after assessment. Nurses in the operating
theatres act as patients’ advocates are always encouraged to carry out high standards
of perioperative nursing care that are supported by evidence-based nursing practice.
Thus nurses in the operation theatres are highly encouraged to implement new
innovations.
Interference on current staff function
The innovation will cause minimal interference on current staff work. In our
current practice, nurses would notify the ward to send the next patient to the operating
room when the current surgery is finishing. When carrying out the innovation, nurses
have to send the case earlier in order to allow enough time for preoperative warming.
This actually facilitates nurses’ workflow. After sending the case, the circulating
nurse can start to perform counting with the scrub nurse, prepare dressing and
documentation when the operation is going to be finished. Sending the next patient in
advance help to relieve nurses’ workload during this busiest period. After admission
26
to the operating room, nurses routinely help patient loosen their gown and provide
some warmed blankets. The application of forced-air blanket for preoperative
warming can be carried out at the same time. Nurses just have to take one to two
minutes checking the patient’s body temperature and the presence of any
contraindications for preoperative warming before carrying out the innovation. The
whole procedure takes less than five minutes and is very easy and not time-consuming.
It is also a familiar procedure for nurses in the operation theatres as we do provide
intraoperative forced-air warming. Thus the interference on current staff functions is
minimal. Instead of releasing nurses from the current practice to implement the
innovation, nurses can integrate the innovation to the current nursing care and this
may facilitate their work as well.
Support from the administration and organization
The administration is expected to support the innovation as new practices are
always welcomed for enhancing patients’ benefit. For example, the department
adopted the project of colorful wall painting in admission area of the operating rooms
in order to attract pediatric patients’ attention and to lower their anxiety for the
operation. The project has gain good support from the administration and organization.
As promoting perioperative normothermia is one of the goals in our department this
year and the implementation of evidence-based practice is being addressed by our
Department Operations Manager (DOM), the organizational climate is conducive to
research utilization on this issue.
Besides, there is a fair degree of consensus among the nurses that the
innovation could be beneficial as we always apply forced-air warming to patients if
they were hypothermia during the intra- or postoperative periods. For testing the
27
innovation as a preventive measure preoperatively, the staff and the administrators are
expected to give welcome and support. Besides nurses, both the anesthetists and
surgeons are likely to support the innovation as the presence of perioperative
hypothermia leads to many complications that challenge their works and result in
poorer patient outcome. Therefore, it is unlikely to have friction or resistance within
the organization as well as from other departments for the implementation of the
innovation.
Equipment and facilities
The innovation will be carried out in the induction rooms in the operating
theatres, which is an existing waiting area for patient before general anesthesia. The
forced-air warming device and blanket are available in the organization but more
number of devices and blankets have to be purchased to meet the increase in usage.
The device will be cleaned after every use and the cleansing agent is available in the
operating theatres. The full-body forced-air blanket will be kept in the induction room
and discarded when broken or dirty. Tympanic thermometer and temperature probe
are required for assessment before the innovation and evaluation of the innovation,
which are all available in the department.
Cost-Benefit Ratio
Before implementing the innovation, the potential risks, benefits, material and
nonmaterial costs of the innovation have to be considered.
28
Potential risks of the innovation
Both Andrzejowski et al (2008) and Kim et al (2006) mentioned about the
potential risk of the innovation were thermal discomfort and perspiration complained
by patients if preoperative warming is continued for too long and the warming
temperature is set high. Besides, some patients with sensitive skin may have the risk
to develop rash after applying the forced-air blanket. Therefore, an optimal duration
and temperature of preoperative warming should be recommended from evidence.
Continuous monitoring on patients body temperature and observation for any patient
discomfort should be ensured.
Potential benefit of the innovation
By providing preoperative forced-air warming, the incidence of perioperative
hypothermia for patients undergoing GA will be reduced by about 25-50%
(Andrzejowski et al., 2008; Horn et al., 2012). This helps to minimize the
complications arise from hypothermia, which include decrease metabolic rate,
coagulopathy, extended reversal from GA and lengthy recovery stay, postoperative
shivering, increase in surgical site infection and wound healing problems (Kumar,
Wong, Melling, & Leaper, 2005; Scott & Buckland, 2006). Thus patient safety will be
improved and better patient outcome will be achieved. Besides, the provision of warm
may relieve patients’ anxiety level for undergoing GA and the surgery, in addition
improve patient’s satisfaction of the perioperative journey (Wagner, Byrne & Kolcoba,
2006). Shorten the period of reversal from GA helps with the efficiency of theatre
turnover, therefore less cancellation of operation may be resulted. The decrease length
of PACU stay also helps relieve nurses’ workload.
29
Risks of maintaining current practice
Without implementation of the innovation, the incidence of perioperative
hypothermia may remain high. The coagulation and platelet dysfunction arise from
hypothermia may lead to increase in blood loss during the surgery and pose more
challenges to the surgical team and extend the operation time. Patient with
hypothermia have a higher chance of developing postoperative shivering,
hyperventilation and increased anxiety level (Horn et al., 2012). The complications of
hypothermia also increase morbidity, surgical site infection and healing problems.
These also lead to prolong hospital stay and increase medical burden of the hospital.
Material costs of implementing the innovation
The material costs include the forced-air warming device, the full body
forced-air blanket, the photocopying of guidelines and the assessment and evaluation
forms. Each warming device cost HK$14,800 and each full-body blanket cost HK$75.
Photocopying of document cost HK$0.3 per page.
For the set up cost, 10 forced-air warming devices have to be purchased to
meet the increase in the usage demand for 15 operation theatres, as there are some
existing extra devices in the department. The full-body blanket will be wrapped in a
cotton blanket and will not touch the patients directly. The cotton blanket will be
changed after every use while the forced-air blanket can be reused. 60 forced-air
blankets have to be purchased for the first set up. The cost of photocopying of the
documents required will also be calculated and the details are shown in Appendix IV.
Together the total set up material cost is estimated to be HK$152,518.
The running cost will be mainly for the purchase of full-body forced-air
blanket and the photocopying of the assessment and evaluation forms. Each blanket
30
will be used for a week in one theatre. Thus, we estimate to purchase 60 forced-air
blankets in total for 15 theatres per month. Each patient requires a page of assessment
and evaluation form. As mentioned before, there are about 300 eligible patients per
month. Therefore taking 3600 eligible patients per year, the running cost will be about
HK$55,080 per year. Details of the calculation were shown in Appendix IV.
Other material cost of implementing the innovation will be the manpower and
venue. Two identical briefing sessions last for about 30 min will be provided for 120
registered nurses (RN) in the operation theatre. Each RN is required to attend once.
According to the pay scale of RN, the average salary of a nurse is estimated to be
HK$180 per hour. The venue, the computer system and projector are available in the
department and are free of charge. Thus the total nonmaterial cost of the innovation
will be HK$10,800. Details of the calculation were shown in Appendix IV.
Nonmaterial benefit of implementing the innovation
After implementing the innovation, the incidence of perioperative
hypothermia is expected to reduce. The improvement in patient safety and the
increase in effectiveness of nursing care improve staff morale and help reduce staff
workload. The decrease in complications help saving extra medical cost spending on
treating surgical site infection, healing problems as well as other morbidities. Shorten
the hospital stay lower the hospital cost as well.
To conclude, although the set up cost and the running cost of implementing
the innovation are quite high, it is very worthy to invest on the innovation as the
subsequent benefits to patients, healthcare professionals and the hospital are much
more significant
31
Evidence-Based Practice Guideline
According to the evidence derived form the reviewed studies in the previous
chapter, an evidence-based guideline of preoperative forced-air warming in reducing
inadvertent perioperative hypothermia for patients undergoing general anesthesia will
be developed. The recommendations will be graded according to the Scottish
Intercollegiate Guidelines Network (SIGN) grading system (SIGN, 2014). The full
guideline was attached in Appendix V.
32
CHAPTER 4: IMPLEMENTATION PLAN
From the previous chapters, an evidence-based guideline was established for
the application of preoperative forced-air warming to IPH. In this chapter, the
implementation plan will be discussed including communication plan, pilot study
plan, evaluation plan, and the basis for the full implementation of the innovation.
Communication Plan
Before implementing the innovation, it is necessary to communicate with the
stakeholders who will be affected by the innovation or may affect the proposed
changes for the innovation. The communication process, the way to initiate, guide and
sustain the changes will be discussed followed.
Identifying the Stakeholders
The stakeholders of the innovation are the administrators, the committee
members leading the changes, the intended users of this evidence-based guideline,
other healthcare professionals and the patients undergoing GA being affected by the
guideline.
The administrators include the DOM and the Ward Managers (WM). Their
approval and support for the proposed guideline are very crucial as they provide
resources and allow manpower for the implementation of the innovation.
A committee team will be formed to initiate, guide and sustain the changes
brought form the guideline. One Advanced Practiced Nurse (APN) and three RNs will
be suggested to recruit for the committee team including myself. As the team takes
the leading role of the guideline, it is important that all the team members are very
33
clear about the guideline and have a consensus for the implementation of the
innovation.
The intended users of the guideline are the operating theatre nurses who carry
out the innovation for the patients. Their workflow will be changed and the workload
will be increased. Therefore their understanding of the implementation of the
innovation is very essential.
Other healthcare professionals including the anesthetists and the surgeons are
also the stakeholders. Although they are not directly related to the innovation, their
support and cooperation are also important for the smooth implementation of the
innovation. Besides, they may have to help provide information or examination in
some situations.
Patients undergoing GA who are included in the innovation will be directly
affected. Clear explanation has to be given to gain their understanding and
cooperation and to prevent any adverse situations such as thermal discomfort.
Communication Process
In order to have a success implementation of the guideline, effective
communication with the stakeholders are very important. They have to be convinced
in order and skillfully. Understanding their points of view, worries and tackle with the
obstacles are essential steps before the implementation.
Communication with administrators
In order to gain support form the administrators, the significance of the
problem, the affirming needs in the department, the gap between our current practice
and the evidence-based practice from the literature, and the benefit of the innovation
34
will be stressed on. Clear visions on the necessity to change and the aims and
objectives to be achieved will be stated. A feasible and well-organized proposal for
the implementation of the guideline will be submitted and presented to the
administrators during the departmental meeting. The budget plan, required resources
and the foreseeable barriers with tackling strategies will also be presented in the
meeting.
Communication with committee members
After the approval from the administrators, a committee team will be formed
to initiate, guide and sustain the change brought from the guideline. Certainly, the
team has to share the same vision and has a throughout understanding of the guideline
as we will act as the leaders, the facilitators and the resources people for the
implementation of the guideline. Application of the innovation will be standardized
within the team before we present to our colleagues. Workloads will be share among
the team members and timeframe for the process will be set. We will keep close
communication for the progress and discuss for any tackled difficulties in regular
meetings. We are also responsible for collecting feedback form the colleagues and
share among the team.
Communication with nursing staff
Communication with nursing staff will be started through promotion by
posters. Two identical briefing sessions will then be held during the in-house
mandatory training sessions, which are held on two Saturday morning so that all staff
will have the chance to attend the briefing sessions. As the nursing staff takes the key
role to implement the innovation and their workload are mostly affected by the
implementation of the guideline. They have to be convinced of the significance and
35
the needs of the innovation with evidence support. The benefits of the innovation to
the patients, the staff themselves and the healthcare system will be highlighted. The
clear and easily followed guideline will be introduced in detailed. The kept updated
guideline document will also be kept in the iPad in each floor of the operating theatre
for easy access. As the procedure of applying the innovation is easy, quick and
familiar to the nursing staff, it is believed that they have the confidence in applying
the innovation. Therefore the key point is to let them trust on the proposed guideline
and willing to implement.
Besides initiation and guidance, sustaining the change process is also
important. The nurses may be willing to implement the innovation but hindered by the
heavy workload or limited manpower. Therefore, regular collection of feedback on
any difficulties from the nursing staff is required. Both the outcome and process
evaluation have to be done regularly. The improvement in patient’s outcome can act
as a reward to the staff and encourage them to sustain the good practice. Besides,
nurses’ compliance will also be assessed monthly by auditing the nursing
documentation.
Communication with other healthcare professionals
As the implementation of the guideline requires earlier pre-medication and
sending the patient to the operation theatre, communication with the anaesthetists and
surgeons is important to facilitate the implementation. Besides, assessment on patients’
medical history and current medical problem is necessary to exclude those patients
who are not suitable for the innovation. The anaesthetists and surgeons may give help
in this part as well. When there are some adverse effects developed after
implementation of the innovation, we may also require their help for examination and
treatment. Therefore, their understanding and support act as the backup for our
36
practice. With the permission of the administrators, we will send email to the Chief of
Service of anesthesiology and department of surgery to introduce and explain the
implementation of the innovation.
Communication with the patients
As said above, the patient has to be sent to the operation theatre earlier for the
implementation of the innovation. That means they have to wait for a longer time in
the theatre before undergoing GA and the surgical procedure. This may increase their
anxiety level and nervousness if we don’t explain well to them. Thus we have to gain
their understanding and cooperation before applying the innovation. Assessments for
the present of any exclusion factors as well as regular temperature monitoring have to
be performed. Patient should be told to voice out any thermal discomfort or presence
of adverse effect as soon as they experience it. The nurse who admits the patient will
be responsible to explain verbally to the patient after admission and before carrying
out the innovation.
Pilot Study Plan
Before implementation the innovation, a pilot test will be conducted to
determine the feasibility of the proposed change and to identify any unexpected
difficulties so as to determine whether revisions of the guideline are required.
Timeframe
After providing the briefing sessions to the nursing staff, the pilot test will
then be launched. It will last for six weeks with four week testing the innovation and
the following two weeks for evaluation of the pilot test.
37
Implementation Plan
The pilot test will be launched in one of the floors of the Operating Theatre
(OT) department, which consists of two operation theatres. The guideline in the
previous chapter will be followed for the implementation of the innovation. Only
patients undergoing GA for elective surgery will be included for the innovation
(Andrzejowski et al., 2008; Erdling & Johansson, 2015; Fettes et al., 2013; Horn et
al., 2012; Kim et al., 2006; Shin et al., 2015). During the pilot test period, the
committee team members will screen the patients who are undergoing scheduled
operations the following day for the age, ASA status, the medical history and their
current medical problem. Eligible patients will be marked on the printed operation list
and the list will be hang over to the nurses who are working in the theatres the next
day. Patients aged over 18 with ASA < 3 will be recruited (Andrezejowski et al.,
2008; Erdling & Johansson, 2015; Fettes et al., 2013; Horn et al., 2012). Patients will
be excluded if they have fever, know infection, thyroid disease, peripheral vascular
disease and neurological disease (Erdling & Johansson, 2015; Fettes et al., 2013; Kim
et al., 2006; Shin et al., 2015). According to the usual scheduled operation list, it is
estimated to have 12 patients who are eligible for the implementation of the
innovation in a week. Thus in total there will be about 48 patients recruited for the
pilot test in a month. Committee members will be responsible to guide and monitor
the implementation.
All operation theatre nurses who have attended the briefing sessions can apply
the innovation. Assessment and patient’s core temperature should be taken before
providing the forced-air warming blanket. Continuous temperature monitoring should
be performed and documented on the nursing chart for temperature monitoring. The
committee members will audit the implementation of the innovation once a week and
38
collect feedback from the nursing staff in that floor. Any difficulties encountered will
be discussed in the committee team and the guideline will be revised accordingly if
required.
Evaluation Plan of Pilot Study
After the four weeks of pilot test, the feasibility for the implementation of the
innovation will be evaluated in the following two weeks. Nurses working on the floor,
which the pilot test carried out, will be invited to complete a questionnaire (Appendix
I) for evaluation. The questionnaire is composed of two parts. There are 8 questions in
Part A, which ask about the nurses’ satisfactory level for the new practice. It includes
the influence on their workload, the availability and sufficiency of the resource
manual and person and the overall satisfactory level to the new practice. Part B
consists of 6 questions asking about the nurses’ confidence level on carrying out the
innovation independently. Likert scale is used in the questionnaire for the nurses to
choose. There are also some open-ended questions for the nurses to express their
opinion. The committee team will then collect the completed questionnaire and revise
the guideline accordingly if required.
Evaluation Plan
In order to evaluate the effectiveness of the innovation, an evaluation plan will
be established as followed to identify outcomes to be achieved and to determine the
nature and number of clients to be involved. The method of data analysis will also be
specified.
39
Outcomes
Patient outcomes
The primary patient outcome of the innovation is to reduce the incidence rate
of IPH for patients undergoing GA. Therefore the number of patients who developed
hypothermia post induction will be measured (Andrzejowski et al., 2008; Fettes et al.,
2013; Hornet al., 2012; Shin et al., 2015). The circulating nurses will record the
baseline temperature, pre-induction temperature, and post-induction temperature at 20
min interval until the end of the surgery on the nursing chart for temperature
monitoring. The PACU nurses will continue the temperature monitoring when
patients arrive PACU. Temperature will be measures at arrival and at 20 min interval
until the patients were discharged to ward. The PACU nurse will record the number of
patients who develop IPH every day. A tympanic thermometer will be used for
temperature monitoring pre-, intra- and post-operatively so as to eliminate the
temperature difference due to the change in measuring tools.
Healthcare provider outcomes
Outcomes for healthcare provides are to increase their job satisfactory and
confidence level on applying the innovation. The questionnaire (Appendix VI) will be
used for evaluation. It will be distributed to all nurses after the implementation.
Besides, the compliance rate of the healthcare providers will also be evaluated by a
monthly audit done by the committee team.
Timeframe
Implementation of the full-scale innovation will start immediately after the
two weeks evaluation of the pilot test and will last for 24 months. The evaluation
40
process will go along with the implementation and a monthly evaluation report will be
generated. The improvement in patient outcomes may increase healthcare satisfaction
and their compliance rate. There will be a four-week evaluation period after the
implementation period for the overall evaluation and to determine whether the
innovation will be fully implemented. Details of the timeframe are shown in
Appendix VII.
Client
Eligibility criteria
Patients aged over 18 years old undergoing GA for elective surgery with ASA
< 3 will be recruited for the innovation. Patients with fever, known infection, thyroid
disease, peripheral vascular disease and neurological disease will be excluded for the
innovation.
Sample size
Sample size is calculated by using Piface statistical power analyzer. One
sample t-test is selected because the mean difference within the same group of clients
was compared. With reference to the study by Kim et al. (2006), by inputting the
mean difference of 0.5°˚C, change of standard deviation (SD) as 3 with 80% power,
the sample size was calculated to be 284. By considering 17% and 12% of dropout
rate in the studies done by Erdling and Johansson (2015) and Fettes et al. (2013)
respectively, the dropout rate of client in this innovation was estimated to be 20%. By
taking 20% of dropout rate, the sample size will be 355. Therefore 355 clients have to
be recruited.
41
Data Analysis
Data collection include patient demographics, number of patients developed
IPH, and the results from the evaluation questionnaire. Data will be analyzed by SPSS
19.0 (IBM Inc. Armonk, NY, USA). Patients’ demographic data will be compared
using chi-square or Fisher’s exact test as appropriate. A two-tail z-test will be used to
test the proportion of patients who developed IPH. For the results from the evaluation
questionnaire, nurses’ satisfactory and confidence level will be analyzed. The
percentage of nurses who choose either “agree” or “strongly agree” in the Likert scale
will be calculated.
Basis for Implementation
Results from Horn et al. (2012) showed 6-13% of patients develop IPH in the
prewarming group while Andrzejowski et al. (2008) showed 32 %. Thus the
innovation will be considered as effective if the percentage of patients developed IPH
is lower than 30%. Besides, the percentage of nurses’ job satisfactory and confidence
level will also determine the effectiveness of the guideline. If more than 80% of
nurses choosing “agree” or “strongly agree” in the questionnaire, the guideline will be
considered as effective. The innovation will be fully implemented if the above two
criteria were fulfilled.
42
Conclusion
Preventing perioperative hypothermia for patients undergoing general
anesthesia is very important to reduce the subsequent complications and improve
patients’ outcome. Evidences from the studies showed that preoperative forced-air
warming is an effective way to help reduce the incidence of perioperative
hypothermia by reducing the core and peripheral temperature gradient thus lower the
effect of core-to-peripheral heat redistribution after induction. With the evidence
extracted from the studies, an evidence-based guideline for providing preoperative
forced-air warming for patients undergoing general anesthesia is established. The
implementation potential is assessed. The subsequent implementation and evaluation
plans are also developed to help promote the successful implementation of the
innovation.
Wong Hoi Ching 2006171980
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097
For more information, visit www.prisma-‐statement.org.
43
Appendix I - PRISMA 2009 Flow Diagram
Records identified through Pubmed, Cochrane Library
(n = 47)
Screen
ing
Includ
ed
Eligibility
Iden
tification
Additional records identified through Google Scholar Engine
(n = 24)
Records after duplicates removed (n = 32)
Records screened (n = 9)
Records excluded (n = 23)
Full-‐text articles assessed for eligibility
(n = 6)
Full-‐text articles excluded, with reasons
(n = 3)
Studies included in qualitative synthesis
(n = 6)
Studies included in quantitative synthesis
(meta-‐analysis) (n = 0)
Wong Hoi Ching
Appendix II - Table of Evidence 2006171980
44
Citation/ Design (Level of Evidence)
Patient Characteristic
Intervention (Method/ Temperature/ Duration)
Comparison Outcome measures
Measuring Tools/Site/ Time Intervals (TI) for body temperature
Effect size/Results
Andrzejow-ski et al. (2008) /RCT (++)
1) Undergoing elective Spinal Surgery 2) Under GA1 3) ASA1 < 3
Prewarming with the Bair Paws® forced-air warming system at 38°C for 60 min (mean duration = 72 ± 26 min) (n=31)
Wearing a Bair Paws® gown without prewarming (n=37)
Primary: (1) Changes in mean core temperature (°C) at 20min intervals post induction Secondary: (2) Incidence of nausea, vomiting and shivering in PACU1 (Intervention: Control) (3) No. of Patient who were hypothermia throughout surgery (%)
Tools: Temporal artery scanner & esophageal temperature probe Site: Temporal artery & Esophagus TI1: Pre-intervention (Tpre), Pre- induction (T0), and at 20min intervals post-induction till 160min (T20-160)
Primary: (Effect size) (1) Tpre: 0, T0: -0.11, T20: 0.22, T40: 0.26, T60: 0.26, T80: 0.22, T100: 0.22, T120: 0.21, T140: 0.07, T160: 0 (p≤0.05 only at T40, T60, and T80) Secondary: (Results) (2) Nausea 3:2, Vomiting 3:1, and Shivering 2:3 (3) 25% in intervention group (p<0.05)
Erdling et al. (2015) /RCT (+)
1) Adults undergoing elective colorectal surgery 2) Under GA and EA2 > 210min 3) ASA < 3
Prewarming with a forced-air device set at 43°C after epidural catheter insertion and continue throughout surgery (mean duration = 42 ± 10min) (n=21)
Warming with a forced-air device after surgical preparation completed (n=22)
Primary: (1) Difference in esophageal temperature between groups (2) Difference in nasopharyngeal temperature between groups Secondary: (3) Relationship between esophageal temperature and age (4) Relationship between esophageal temperature and BMI2 at 210 min (BMI <25 and ≥25)
Tools: Esophageal and nasopharyngeal temperature probes Site: Lower esophagus and nasopharynx TI1: Pre-intervention, Pre-induction, before surgery start, and at 30min intervals during surgery till 210 min
Primary: (Effect size) (1) 0.46 (p=0.001) (2) 0.46 (p=0.002) Secondary: (Results) (3) A negative correlation between esophageal temperature and age (p<0.012) (4) Statistical differences between esophageal temperature and 2 BMI groups (BMI <25 and ≥25) at 35.81 ± 0.66 and 36.46 ± 0.59 (p<0.001)
1) GA = General Anesthesia; ASA = American Society of Anesthesiologists physical status classification system; PACU = Post-anesthesia Care Unit; TI = Time Intervals; T40, T60 and T80 = Core temperature at 40min, 60 min and 80min after induction 2) EA = Epidural analgesia; BMI = Body Mass Index (kg/m2
Wong Hoi Ching
Appendix II - Table of Evidence 2006171980
45
Citation/ Design (Level of Evidence)
Patient Characteristic
Intervention (Method/ Temperature/ Duration)
Comparison Outcome measures
Measuring Tools/Site/ Time Intervals (TI) for body temperature
Effect size/Results
Fettes et al. (2013) /RCT (-)
1) Adults between 18 & 85 years old 2) Speak in English 3) ASA < 3 4) Body temperature between 36.5 and 37.5°C
Prewarming with forced-air warming blanket set at 37.8°C for about 60 min (n=54)
Covering with a warm cotton blanket and a forced-air warming blanket without turning on (n=74)
Primary: (1) Patient’s temperature on admission to PACU (°C) (2) Post-anesthesia care unit length of stay (min)
Tools: Temporal artery scanner Site: Temporal artery TI: Pre-induction and on admission to PACU
Primary: (Results) (1) 0.1°C in intervention group (p=0.314) (2) -2.6min in intervention group (p=0.526)
Horn et al. (2012) /RCT (++)
1) Healthy adults ≥18 years old 2) Scheduled for surgery with expected duration of 30-90 min 3) Under GA 4) ASA < 3
Active pre-operative forced-air warming at 44°C for 10, 20 or 30 min (n=52, 43 and 50 respectively)
Passive insulation (no active pre-operative warming) (n=55)
Primary: (1) No. of patient who were hypothermia at arrival of PACU (%) (2) No. of patients experienced shivering in PACU (%) Secondary: (3) No. of patient required active warming during surgery (%) (4) No. of patient required active warming in PACU (%)
Tools: Tympanic temperature sensor Site: Tympanic membrane TI: At 10min intervals after arrival pre-op care unit, 15min interval after arrival theatre and PACU
Primary: (Results) (1) -56%, -62% and -63% in 10, 20 and 30 min intervention group respectively (p<0.05) (2) -13%, -11% and -16% in 10, 20 and 30 min intervention group respectively (p<0.05) Secondary: (Results) (3) -36%, -65% and -61% in 10, 20 and 30 min intervention group respectively (p<0.05) (4) -52%, -63% and -57% in 10, 20 and 30 min intervention group respectively (p<0.05)
Wong Hoi Ching
Appendix II - Table of Evidence 2006171980
46
Citation/ Design (Level of Evidence)
Patient Characteristic
Intervention (Method/ Temperature/ Duration)
Comparison Outcome measures
Measuring Tools/Site/ Time Intervals (TI) for body temperature
Effect size/Results
Kim et al. (2006) /RCT (++)
1) Undergoing OPCAB3
Warming with a Bair Hugger® forced-air heater set at 40°C before induction of anesthesia (mean duration = 49.7 ± 9.9 min) (n=20)
Covering with two cotton blankets (n=20)
Primary: (1) Changes in mean skin temperature (°C) at 30min intervals post induction (2) Changes in mean core temperature (°C) at 30min intervals post induction Secondary: (3) Hemodynamic changes include cardiac index, MAP3, CVP3, MPAP3, heart rate, and SVRI3
Tools: Skin temperature probe & Pulmonary artery catheter Site: Right index finger & Core temperature TI: Pre-induction (T0), and at 30min interval post-induction till 90min (T30-90)
Primary: (Effect size) (1) T0: 0.26, T30: 0.08, T60: 0.10, and T90: 0.03 (p<0.05) (2) T0: 0, T30: 0.31, T60: 0.28, and T90: 0.34 (p<0.05) Secondary: (Effect size) (3) No statistically significant differences in hemodynamic variables between two groups except MAP & CVP
Shin et al. (2015) /RCT (++)
1) Patients aged 20-80 years 2) Undergoing elective or emergency endovascular treatment of cerebral aneurysm 3) Under GA
Prewarming with a forced-air warming blanket set at 38°C for 30min with intraoperative warming (n=36)
Covering with two layers of cotton blanket without prewarming, with intraoperative warming (n=36)
Primary: (1) Changes in mean core temperature (°C) at 20min intervals post induction (2) No. of patient who were hypothermia at 20min intervals post induction (%) Secondary: (3) No. of patient developed procedure-related complication (%) (4) No. of patient experienced shivering in PACU (%)
Tools: Infrared tympanic thermometer and esophageal temperature probe Site: Tympanic membrane and esophagus TI: Pre-induction (Tpre), after intubation (T0), and at 20min intervals during surgery till 120min
Primary: (Results) (1) T0: 0.1°C, T20: 0.4°C, T40: 0.5°C, T60: 0.4°C, T80: 0.4°C, T100: 0.4°C, T120: 0.4°C in intervention group (p=0.007 at T20, p<0.001 at T 40-120) (2) T0: -8.3%, T20: -25%, T40: -50%, T60: -60%, T80: -52.6%, T100: -49.7%, T120: -23.8% in intervention group (p=0.002 at T20, p<0.001 at T 40-120) Secondary: (Results) (3) IAP4 1:1; Thromboembolic complication 1:2 (Intervention: control) (p=0.840) (4) -12% in intervention group (p=0.283)
3) OPCAB = Off-pump coronary artery bypass surgery; MAP = Mean arterial pressure; CVP = Central venous pressure; MPAP = Mean pulmonary arterial pressure; SVRI = Systemic vascular resistance index 4) IAP = Intraprocedural aneurysmal perforation
Wong Hoi Ching Appendix III – Summary of Appraisal Results 2006171980
47
In a well conducted RCT study… Does the study do it?
Andrzejowski et al., 2008 Erdling et al., 2015 Fettes et al., 2013 Horn et al., 2012 Kim et al., 2006 Shin et al., 2015
SECTION 1: INTERNAL VALIDITY
1.1 The study addresses an appropriate and clearly focused question. Yes Yes Yes Yes Yes Yes
1.2 The assignment of subjects to treatment groups is randomized. Yes Yes Yes Yes Yes Yes
1.3 An adequate concealment method is used. Yes Can’t say Can’t say Yes Yes Yes
1.4 The design keeps subjects and investigators “blind” about treatment allocation.
Not Applicable Not Applicable Not Applicable Not Applicable Not Applicable Not Applicable
1.5 The treatment and control groups are similar at the start of the trial. Yes Yes Yes Yes Yes Yes
1.6 The only difference between groups is the treatment under investigation. Yes Yes Yes No Yes Yes
1.7 All relevant outcomes are measured in a standard, valid and reliable way.
Yes Yes Yes Yes Yes Yes
1.8
What percentage of the individuals or clusters recruited into each treatment arm of the study dropped out before the study was completed?
0% 17% 12% 0% 0% 0%
1.9
All the subjects are analysed in the groups to which they were randomly allocated (often referred to as intention to treat analysis).
Yes No No Yes Yes Yes
1.10 Where the study is carried out at more than one site, results are comparable for all sites.
Not Applicable Not Applicable Not Applicable Not Applicable Not Applicable Not Applicable
Wong Hoi Ching Appendix III – Summary of Appraisal Results 2006171980
48
In a well conducted RCT study… Does the study do it?
Andrzejowski et al., 2008 Erdling et al., 2015 Fettes et al., 2013 Horn et al., 2012 Kim et al., 2006 Shin et al., 2015
SECTION 2: OVERALL ASSESSMENT OF THE STUDY
2.1
How well was the study done to minimize bias? (High quality: ++, Acceptable: +, Low quality: -, Unacceptable – reject: 0)
++ + - ++ ++ +
2.2
Taking into account clinical considerations, your evaluation of the methodology used, and the statistical power of the study, are you certain that the overall effect is due to the study intervention?
Yes Yes Can’t say Yes Yes Yes
2.3 Are the results of this study directly applicable to the patient group targeted by this guideline?
Yes Yes Yes Yes Yes Yes
2.4
Notes. Summarise the authors’ conclusions. Add any comments on your own assessment of the study, and the extent to which it answers your question and mention any areas of uncertainty raised above.
- It is concluded that 60 min of prewarming is effective to attenuate the redistribution hypothermia after anesthesia and decrease the incidence of IPH - The conclusion is supported by the study results
- It is concluded that prewarming has a positive effect on core temperature of patients under GA - The conclusion is supported by the study results
- It is concluded that prewarming does not significantly affect patient’s postoperative temperature. - The differences in group sample size may affect the statistical outcomes
- It is concluded that prewarming of 10, 20 or 30 min reduced the risk of perioperative hypothermia - There is no significant differences between 10, 20 or 30 min of prewarming groups - The conclusions are supported by the study results
- It is concluded that prewarming reduced the incidence and degree of redistribution hypothermia in patients undergoing OPCAB1 - The conclusion is supported by the study results
- It is concluded that 30 min of prewarming at 38°C was not enough to prevent the decrease in core temperature but reduce the incidence of hypothermia - The conclusion is supported by the study results
1) OPCAB = Off-pump coronary artery bypass surgery
Wong Hoi Ching 2006171980
49
Appendix IV – Summary of Costs of the Implementation of the Innovation Material Cost: Set-up cost Category Calculation Sub-total
Forced-air warming device $14,800 x 10 $148,000
Full-body forced-air blanket $75 x 60 $4,500
Photocopying of guidelines (10 pages/set)
$0.3 x 10 x 6 $18
Total $152,518
Running cost per year Category Calculation Sub-total
Full-body forced-air blanket $75 x 60 x 12 $54,000
Photocopying of assessment & evaluation form (1 pages/set)
$0.3 x 3600 $1,080
Total $55,080
Training cost Average 30 min salary of RN $90 X Number of RN in operation theatre 120 Total nonmaterial cost for the briefing sessions $10,800
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50
Appendix V - Evidence-Based Practice Guideline
Introduction
As inadvertent perioperative hypothermia is very common in patients
undergoing general anesthesia, the implementation of preoperative forced-air
warming is recommended with evidence support. An evidence-based guideline is
developed to provide instruction for nurses in the operation theatres on the provision
of preoperative forced-air warming for patients undergoing general anesthesia.
Title
An evidence-based guideline on providing preoperative forced-air warming
for patients undergoing general anesthesia
Aim
To reduce the incidence of perioperative hypothermia
Objectives
1) To provide an evidence-based guideline for nurses on providing preoperative
forced-air warming for patients undergoing general anesthesia
2) To standardize the nursing care related to the provision of preoperative forced-
air warming for patients undergoing general anesthesia
Intended Users
Nurses working in the operation theatres in the public hospital in HKWC
Wong Hoi Ching 2006171980
51
Target Population
Patients aged over 18 year old with American Society of Anesthesiologists
physical status classification system (ASA) < 3 undergoing general anesthesia for
elective surgery are the target population. Patients with fever, known infection,
thyroid disease, peripheral vascular disease and neurological disease are excluded.
Recommendations
The following recommendations are concluded with evidenced support from
the reviewed studies. The Scottish Intercollegiate Guidelines Network (SIGN)
grading system (SIGN, 2014) was used to grade the recommendations and the levels
of evidence (Appendix VI).
Recommendation 1
The eligible population should include adult patient aged > 18 year old with
ASA < 3 undergoing general anesthesia for elective surgery
(Grade of recommendation – A)
Evidence:
All studies include adult patients undergoing GA (Andrzejowski et al., 2008
(1++); Erdling & Johansson, 2015 (1+); Fettes et al., 2013 (1-); Horn et al., 2012
(1++); Kim et al., 2006 (1++); Shin et al., 2015 (1++)). Four studies mentioned about
the ASA status to be < 3 (Andrezejowski et al., 2008 (1++); Erdling & Johansson,
2015 (1+); Fettes et al., 2013 (1-); Horn et al., 2012(1+)).
Recommendation 2
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Patients with fever, known infection, thyroid disease, peripheral vascular disease
and neurological disease should be excluded for the preoperative forced-air
warming
(Grade of recommendation – A)
Evidence:
Four studies excluded patients with fever, thyroid disease and peripheral
vascular disease (Erdling & Johansson, 2015(1+); Fettes et al., 2013(1-); Kim et al.,
2006(1++); Shin et al., 2015(1++)). Three studies excluded patients with known
infection and neurological disease (Fettes et al., 2013(1-); Kim et al., 2006(1++); Shin
et al., 2015(1++)).
Recommendation 3
A full-body forced-air warming blanket should be used for the preoperative
warming
(Grade of recommendation – A)
Evidence:
All studies used forced-air warming blanket for preoperative warming
(Andrzejowski et al., 2008 (1++); Erdling & Johansson, 2015 (1+); Fettes et al., 2013
(1-); Horn et al., 2012 (1++); Kim et al., 2006 (1++); Shin et al., 2015 (1++)). Four
studies mentioned about using full-body blanket (Andrzejowski et al., 2008 (1++);
Horn et al., 2012 (1++); Kim et al., 2006 (1++); Shin et al., 2015 (1++)).
Recommendation 4
The temperature of the forced-air warming device should be set between 40-
44°C
Wong Hoi Ching 2006171980
53
(Grade of recommendation – A)
Evidence:
Three studies set the temperature of the forced-air warming device between
40-44°C and got significant results (Erdling & Johansson, 2015 (1+); Horn et al.,
2012 (1++); Kim et al., 2006 (1++)).
Recommendation 5
The duration of the preoperative forced-air warming should be ≥ 30 min
(Grade of recommendation – A)
Evidence:
Majority of the studies prewarmed the patients ≥ 30 min ranging from 30 to 72
min ((Andrzejowski et al., 2008 (1++); Erdling & Johansson, 2015 (1+); Fettes et al.,
2013 (1-); Kim et al., 2006 (1++); Shin et al., 2015 (1++)).
Recommendation 6
Patients’ baseline body temperature should be measured before providing the
preoperative forced-air warming
(Grade of recommendation – A)
Evidence:
There studies mentioned about the significance of taking the baseline body
temperature before applying the preoperative warming (Andrzejowski et al., 2008
(1++); Horn et al., 2012 (1++); Kim et al., 2006 (1++))
Recommendation 7
Wong Hoi Ching 2006171980
54
Patients’ preoperative, intraoperative and postoperative body temperature
should be monitored at 20 min interval
(Grade of recommendation – A)
Evidence:
In majority of the studies, the preoperative, intraoperative and postoperative
temperature are monitored at a interval ranging from 10 – 30 min (Andrzejowski et
al., 2008 (1++); Erdling & Johansson, 2015 (1+); Horn et al., 2012 (1++); Kim et al.,
2006 (1++); Shin et al., 2015 (1++)).
Recommendation 8
During the preoperative warming period, patient’s thermal comfort should be
asked every 5 min. Lower the temperature of the warming device or terminate
the warming if patient complain of thermal discomfort or develop any adverse
reactions.
(Grade of recommendation – A)
Evidence:
Horn et al. (2012) (1++) stated the significance of monitoring for any thermal
discomfort by asking patients every 5 min. The warmer was lowered if they patients
felt overheated.
55
Appendix VI
Key to Evidence Statements and Grades of Recommendations (SIGN, 2011)
Wong Hoi Ching 2006171980
56
Appendix VII Questionnaire on Preoperative Forced-air Warming Application for Nurses Dear colleagues, Thank you for taking part in the application of preoperative forced-air warming for patients undergoing general anaesthesia in elective surgery. To evaluate the effectiveness of the new guideline, please spare 5 minutes time help us complete the following questionnaire. Your kindly help is much appreciated. Thank you. Part A – Satisfaction on preoperative forced-air warming application (Please tick the answer that most represent your feeling about the statement)
Strongly Disagree Disagree Neutral Agree Strongly
Agree
1. The application is easy to be carried out.
2. The application does not increase my workload.
3. The guideline manual is easy to locate.
4. The guideline is easy to follow.
5. The guideline provides enough information.
6. The resource person is easy to reach.
7. The resource person provides enough information.
8. Overall, I am satisfied with the new practice.
Do you have any suggestion about the preoperative forced-air warming application?
Wong Hoi Ching 2006171980
57
Part B - Confidence on preoperative forced-air warming application (Please tick the answer that most represent your feeling about the statement)
Strongly Disagree Disagree Neutral Agree Strongly
Agree
1. I am confident on patient assessment to recruit eligible patients.
2. I am confident on applying the new practice.
3. I am confident to explain the application to patients.
4. I am confident to manage the workflow of the new practice.
5. I am confidence on patient temperature monitoring.
6. Overall, I am confident of the new practice.
Do you have any suggestions to increase your confidence on preoperative forced-air warming application?
Wong Hoi Ching 2006171980
58
Appendix VIII
Timeframe of the Implementation and Evaluation of the Innovation
Week Schedule 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44
Preparation
Staff briefing
Pilot test with evaluation
Implementation
Evaluation
59
References
Andrzejowski, J., Hoyle, J., Eapen, G. & Turnbull, D. (2008). Effect of prewarming
on post-induction core temperature and the incidence of inadvertent
preoperative hypothermia in patients undergoing general anesthesia. British
Journal of Anaesthesia, 101(5), 627-631.
Smith, C. E., Desai, R., Glorioso, V., Cooper, A., Pinchak, A. C., & Hagen, J. F.
(1998). Preventing hypothermia: convective and intravenous fluid warming
versus convective warming alone. Journal of Clinical Anesthesia, 10(5), 380-
385.
Cheng, T. N. (2013). An evidence-based guideline on preoperative warming of
patients undergo general anesthesia to reduce postoperative hypothermia.
Unpublished master’s thesis, The University of Hong Kong.
Erdling, A., & Johansson, A. (2015). Core temperature – the intraoperative difference
between esophageal versus nasopharyngeal temperatures and the impact of
prewarming, age, and weight: a randomized clinical trial. American
Association of Nurse Anesthetists Journal, 83(2), 99-105.
Fettes, S., Mulvaine, M., & Doren, E. V. (2013). Effect of preoperative forced-air
warming on postoperative temperature and postanesthesia care unit length of
stay. Association of perioperative Registered Nurses Journal, 97(3), 323-328.
Frank, S. M., Shir, Y., Raja, S. N., Fleisher, L. A., & Beattie, C. (1994). Core
hypothermia and skin-surface temperature gradients: epidural versus general
anesthesia and the effects of age. Anesthesiology, 80(3), 502-508.
Hooven, K. (2011). Preprocedure warming maintains normothermia throughout the
60
perioperative period: a quality improvement project. Journal of
PeriAnesthesia Nursing, 26(1), 9-14.
Horn, E. P., Bein, B., Böhm, R., Steinfath, M., Sahili, N., & Höcker, J. (2012). The
effect of short time periods of pre-operative warming in the prevention of peri-
operative hypothermia. Anaesthesia, 67, 612-617. doi: 10.1111/j.1365-
2044.2012.07073.x
Ihn, C. H., Joo, J. D., Chung, H. S., Choi, J. W., Kim, D. W., Jeon, Y. S., et al. (2008).
Comparison of three warming devices for the prevention of core hypothermia
and post-anesthesia shivering. Journal of International Medical Research,
36(5), 923-931.
Kim, J. Y., Shinn, H., Oh, Y. J., Hong, Y. W., Kwak, H. J., & Kwak, Y. L. (2006).
The effect of skin surface warming during anesthesia preparation on
preventing redistribution hypothermia in the early operation period of off-
pump coronary artery bypass surgery. European Journal of Cardio-thoracic
Surgery, 29, 343-347.
Kumar, S., Wong, P. F., Melling, A. C., & Leaper, D. J. (2005). Effects of
perioperative hypothermia and warming in surgical practice. International
Wound Journal, 2, 193–204.
Kurz, A. (2008). Thermal care in the perioperative period. Best Practice & Research
Clinical Anaesthesiology, 22, 39–62.
Kurz, A., Sessler, D. I., & Lenhardt, R. (1996). Perioperative normothermia to reduce
the incidence of surgical-wound infection and shorten hospitalization: Study
of Wound Infection and Temperature Group. The New England Journal of
Medicine, 334(19), 1209-1215.
Leslie, K., Sessler, D. I., Bjorksten, A. R., Moayeri, A. (1995). Mild hypothermia
61
alters propofol pharmacokinetics and increases the duration of action of
atracurium. Anesthesia and Analgesia Journal, 80(5), 1007-1014.
Mahoney, C. B., & Odom, J. (1999). Maintaining intraoperative normothermia: a
meta-analysis of outcomes and costs. American Association of Nurse
Anesthetists Journal, 67(2), 155-164.
Rajagopalan, S., Mascha, E., Na, J., & Sessler, D. I. (2008). The effects of mild
perioperative hypothermia on blood loss and transfusion requirement.
Anesthesiology, 108(1), 71-77.
Röder, G., Sessler, D. I., Roth, G., Schopper, C., Mascha, E. J., & Plattner, O. (2011).
Intraoperative rewarming with HotDog resistive heating and forced-air heating:
a trial of lower-body warming. Anaesthesia, 66(8), 667-674.
Sessler, D. I. (2001). Complications and treatment for mild hypothermia.
Anesthesiology, 95(2), 531-543.
Shin, K. M., Ahn, J. H., Kim, I. S., Lee, J. Y., Kang, S. S., Hong, S. J., et al. (2015).
The efficacy of pre-warming on reducing intraoprocedural hypothermia in
endovascular coiling of cerebral aneurysms. BioMed Central Anesthesiology,
15(8). Retrieved from http://www.biomedcentral.com/1471-2253/15/8
Scott, E. M., & Buckland, R. (2006). A systematic review of intraoperative warming
to prevent postoperative complications. American Operating Room Nursing
Journal, 83, 1090–1113.
Wagner, D., Byrne, M., & Kolcaba, K. (2006). Effects of comfort warming on
preoperative patients. Association of PeriOperative Registered Nurses, 84,
427-428.