Journal Club October 17, 2013 Russell Quapp, PGY-4.
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Transcript of Journal Club October 17, 2013 Russell Quapp, PGY-4.
Journal Club
October 17, 2013
Russell Quapp, PGY-4
Incidence reports vary widely:6.6 – 90%21-65%53 – 57% with double lumen tubes25 – 57%100% ....
The post-operative sore throat
Etiology:We stick something into peoples’ tracheas that
don’t belong there....
Risk factors
Preventative measuresNon-pharmacologicPharmacologic
The post-operative sore throat (POST)
Anesthesia and Analgesia; 2009. 40 patients in two groups.
Why might licorice work?
Many active ingredients:Glycyrrhizin – anti-inflammatory/anti-allergic
propertiesGlycyrrhizic acid – inhibits COX activity, PG
formation, platelet aggregationLiquilitin, Liquiritigenin glabridin – antitussives
(peripherally/centrally)Hispaglabridins – antioxidant/ulcer healing
properties
Why might licorice work?
Figure 1
Surgery size:
Small (thoracoscopy)
Medium (thoracotomy <3h)
Large (thoractomy >3h or blood loss >1000mL)
Patient Demographics
Premedicated with oral midazolam (up to 7.5 mg)Randomized:
Licorice extract Sugar solution
Gargle for at least one minute sitting Induction five minutes post gargling (fentanyl, propofol,
rocuronium) Intubation following loss of TOF with DL ETT
(*unlubricated) with cuff pressures of 20 mmHg Intra-operative analgesia with narcotics/paracetamol and a
intercostal plexus block at the end of surgeryExtubated “while still anesthetized”Post-operative analgesia with piritramide (synthetic opioid
slightly weaker than morphine)
Protocol
Measurements were taken at 30 minutes, 90 minutes after arrival in PACU and 4 hours post extubation11 point Likert scale (0 – 10)
Also assessed pain on swallowing at 30 minutes.Any score >0 defined as a sore throat.Coughing assessed by observation and questioning
the patient at 0, 30, 90 minutes post extubation.None = 1Mild = 2Moderate = 3 (similar to common cold)Severe = 4
Above measures repeated on first morning post-op.
Measurement
Interim AnalysisEfficacy
Futility
Harm
Primary outcome:Effect of licorice gargle on occurrence of sore
throat at rest after intubation with DL ETT compared with sugar-water through the first four postextubation hours.
Secondary outcomes:Effect of licorice on sore throat on
postoperative day 1Incidence of sore throat during swallowing
assessed at 0.5 hours post PACU arrivalIncidence of coughing over 5 time
measurementsAmount of coughing over 5 time measurements
Outcomes
Analysis Measurements
Results
Statistical black box of number crunching
Overall RR = 0.46 (0.29-0.72)
Results
Results
Validity - Sniff test?Seems to be okay – particularly for the
primary outcome.Do I care particularly about coughing end
points?Decreased coughing would likely be decreased
pain in the post-thoractomy patient.
Primary assess effect of licorice gargle on sore throat at
rest after intubation with DL ETT compared with sugar water at 0.5, 1.5, 4 hours.
SecondarySore throat at rest POD 1Incidence of sore throat during swallowing at
0.5 hoursOverall difference in pain scores between at
rest and swallowing at 0.5 hours and across four time points.
Incidence of coughing and amount/severity of coughing
Validity – Clearly defined outcomes?
Pain vs. No painObjective outcome
Amount of pain (0-10)More subjective, but validated scale
Incidence of coughingObjective
Amount of coughingVery subjective.? Validated (was published previously)
Validity – Measurements
Validity - Randomization?“Web-based” system used just prior to
procedure.Don’t state what system in particular was
used…
Validity - Randomization – groups similar?
>0.2 standardized difference would indicate imbalance
Validity - Blinding?Randomization with computerized system by
“independent researcher” not involved in subsequent data collection
Licorice/sugar preparations by “independent apothecary”
Independent researcher not involved in data collection used to supervise gargling
Patients not told which solution they were usingThough likely could tasteWere only told they would be trying two
different “sweet” solutions
Validity - Blinding?Assessments in PACU were done by nurses
“not present” for garglingPossible patient’s could mention what flavor
they had when gargling….Post-operative assessment on day 1 done by
“independent and blinded investigator”Again, possible that patient could mention/tell
investigator what they had tasted
Validity - Intention to treat/loss to follow up?One patient in each arm was lost to follow-up
Both remained intubated post surgeryLicorice group
Results were entered as “worst case scenario”i.e. sore throat at all time points, coughing at
all time pointsSugar group
Results entered as “best case scenario”i.e. no sore throat at any time point and no
coughing at any time pointAlso one patient withdrawn secondary to
emergency surgery
Validity - Similar to our patient population?
Looks similar
DL ETT vs. Single lumen ETTIncidence with DL ETT likely higherWould relative risk/treatment effect be as
pronounced with single lumen tubes?Previous study was with single lumen tubes
Thoracic/Thoracotomy patientsNo documentation of comparability of opioids
administered during cases.Hopefully similar between groups
No documentation regarding airway grading/difficulty
Use of dexamethasone?
Limitations/Weaknesses
Why bother with the safety analysis?
Given the low pain scores in their study, how important a complication is it?
Limitations/Weaknesses
Two studies now showing nearly identical results2 fold decrease in incidence of post-operative
sore throatStatistically significant resultsShould this change my practice?
How much do I care about POSTIncidence seems relatively highBut how bad is it (very low pain scores in this
study)Is there any monetary cost (work days lost,
prolonged hospital stay etc.) associated with POST
Doesn’t appear to be any harm, likely very inexpensive, potential benefit...
What about LMA’s?
Will this change my practice?