OSA & Paediatric Adenotonsillectomy

David O’Hara

Consultant Anaesthetist

Preoperative assessment

Outline

• Paediatric pre assessment

• OSA in children

• Risk stratification in OSA

• Adenotonsillectomy at MEHT

• Literature review

• National and international guidelines

Broomfield hospital, Chelmsford

• ENT centre for Essex & East London

• No Paediatric HDU

• Paediatric Surgery: 3332 children with 461 under 2 years of age

• Supra regional burns & plastics service (incl cleft centre) to a population of 9.8 million

Paediatric pre assessment at MEHT

2012 x 3 post op AT transfers of children by CATS in 3 months all from outlier units

Consultant led clinics & benchmarked to APA & Great Ormond St standards

PAC figures

Oct 2014-2015 : Cons 153 Nurse: 1421

Jan 2016-2017: Cons 263 Nurse; 2069

Wizard Team

1 x Band 7 (1 WTE)

3 x Band 6 (1.9 WTE)

7 x Band 5 (5 WTE)

2 x Band 4 (Nursery Nurses 2 WTE)

1 x Band 4 Play Specialist (0.8 WTE)

No CATS transfer post AT surgery since 2012

GOSHSheffield children’s Hospital.Paediatric Anaesthesia 2015

Criteria for referral for physician led pre-assessment for children scheduled for surgery.

All primary cleft children should be pre-assessed by an anaesthetist

Other children who should be referred for anaesthetic pre-assessment :

• Ex-prem infants and children - >6 weeks premature and/or IPPV

• Any syndromic children

• Any previous anaesthetic difficulty

• A strong family history of anaesthetic related problems (MH/Sux apnoea)

• Any known airway problems including OSA

• Any children significantly underweight (<5th percentile or acute drop)

• Are significantly obese (>95th percentile for age and gender)

• Any significant coexisting disease e.g. poorly controlled asthma, diabetes, epilepsy, cardiac conditions, myopathy, chronic lung disease, ASA 3 or above)

• Children with URTI if surgery is planned within the next 2 weeks

• Surgery >2 hours or complicated surgery

• A child with moderate / severe preoperative anxiety to formulate a plan

OSA Incidence

• 12% of children aged 4-5 years of age in the UK snore on a regular basis.

• They may have associated nocturnal and daytime symptoms;

• A small proportion develop complications including failure to thrive, poor school performance, secondary enuresis, and rarely, cor pulmonale.

Sleep Related Breathing Disorders

Continuum of severity

• Partial upper airway obstruction

Primary snoring (5 – 12%)

• Intermediate conditions

Upper airway resistance syndrome

Obstructive hypoventilation

• Episodes of upper airway obstruction

OSA (1 – 4%)

Left untreated..?

Neurocognitive/psychological

Behavioural

Failure to thrive

Poor school performance

Cardiovascular dysfunction

Pulmonary disease

What’s the big deal…

• Children with OSA are at increased risk for post-Tonsillectomy respiratory complications A&A 2009

• Incidence up to 27% BJA 2013

• Airway obstruction

• Post-obstructive pulmonary oedema

Relief of longstanding PEEP

• Pneumonia

• Respiratory failure

Most important risk factor…

Severity of OSA

BUT…

It is the most difficult risk factor to assess

A&A 2011

Coexisting medical conditions and young age –close runners up

Perioperative Management of Children withObstructive Sleep Apnea

Numerous authors have demonstrated that paediatric patients with OSA are at increased risk for postoperative respiratory complications

• Brown KA, et al Recurrent hypoxemia in young children with obstructive sleep apnea is associated with reduced opioid requirement for analgesia. Anesthesiology 2004

• Sanders JC, et al Perioperative complications of adenotonsillectomy in children with obstructive sleep apnea syndrome. Anesth Analg 2006

• Statham MM, et al Adenotonsillectomy for obstructive sleep apnea syndrome in young children: prevalence of pulmonary complications. Arch Otolaryngol Head Neck Surg 2006

• Brown KA, Urgent adenotonsillectomy: an analysis of risk factors associated with postoperative respiratory morbidity. Anesthesiology 2003

High risk predictors…

Overnight oximetry nadir <85%

Severe OSA on PSG or oximetry

Young age - <2

Co-morbid conditions (craniofacial, syndromes, muscular, weight < 3rd centile, obesity, airway)

A retrospective analysis of 4092 consecutive patients undergoing tonsillectomy over a two-year period. The Laryngoscope 2013

Diagnosis OSA

History

Overnight oximetry

Polysomnography (sleep study)

HistoryGOSH guide/ BMJ 2013,2017

Ask about night time symptoms

• Do they snore?

• Do they get a good night’s sleep or are they restless?

• Do they wake through the night?

• Do they struggle with their breathing or stop breathing?

• Do they sleep in an unusual position (such as with extended head)?

• Do they sweat excessively?

• Do they wet the bed?

Ask about daytime symptoms

• Do they have any behavioural or concentration problems?

• Do they breathe through their mouth?

• Are they growing normally?

• Is there severe difficulty chewing and swallowing solid food

• Is there a family history of OSA?

OSA Severity scoring GOSH

Who goes home from MEHT

• Weight at least 15Kg

• No significant OSA (normal oximetry)

• No major medical co-morbidity

• Car, Sensible parents, Phone

• Within Travel time to nearest A & E 30 mins

• Eat, drink, analgesia

• 6 hour stay in recovery

• No bleeding

Tonsillectomy and Adenoidectomy in Children with Sleep Related Breathing Disorders

• Consensus statement of a UK multidisciplinary working party Issued September 2008, reviewed July 2010

• Children with severe OSA or significant co-morbidity must be referred for preoperative paediatric respiratory assessment; these children will usually require surgical management in a paediatric centre with direct and immediate access to PHDU and PICU.

Children at risk from respiratory complications unsuitable for DGH

adenotonsillectomy

• Age <2 years with co morbidities• Weight <15kg with co morbidities• Failure to thrive (weight <5th percentile for age)• Obesity (>99th percentile for age and gender)• Severe cerebral palsy• Hypotonia or neuromuscular disorders (moderate or severely affected)• Significant craniofacial anomalies• Mucopolysaccharidoses and syndromes associated with difficult airway • Significant comorbidity (e.g. congenital heart disease, chronic lung

disease. ASA 3 or above)• ECG or echocardiographic abnormalities• Severe OSA (PSG indices: AHI >10, Respiratory Disturbance Index >40, and

Oxygen saturation nadir <80%)

AHI: Apnoea-Hypopnea Index

Consensus statement Conclusions

• “Post-operative severe respiratory complications requiring PICU facilities in children undergoing AT for SDB occur, but, in a typical non-selected population presenting to a UK DGH, are probably uncommon.”

• “This should allow the majority of children to be managed in the DGH setting by appropriately trained personnel with sufficient caseload to maintain skills.”

• “A relatively discrete population is at additional risk and should be operated on in the regional/sub-regional centreable to provide an additional tier of post-operative respiratory care (HDU).”

American Academy of Pediatrics CLINICAL PRACTICE GUIDELINE Diagnosis and Management of Childhood Obstructive Sleep Apnea

Syndrome Pediatrics 2012

• Key recommendation: High-risk patients should be monitored as inpatients postoperatively & undergo surgery in a center capable of treating complex pediatric patients.

• They should be hospitalized overnight for close monitoring postoperatively and have CPAP available (HDU).

• “all patients with a lowest oxygen saturation <80% on preoperative polysomnography or an AHI ≥10/h”

Anesthesiology 2014

• An Updated Report by the American Society of Anesthesiologists Task Force on Perioperative Management of Patients with Obstructive Sleep Apnea

“Hospitalized patients who are at increased risk of respiratory compromise from OSA should have continuous pulse oximetry monitoring after discharge from the recovery room. Continuous monitoring may be provided in a critical care or stepdown unit,”

HDU

How to read a sleep study

• Is it a PSG or Overnight O2 sats

• Is it an in lab test, a home sleep test

• AHI: What was the overall Apnoea/Hypopnea Index (AHI)?

• The AHI is the measure of how bad the patient’s sleep apnoea is. In a child > 1.5 indicates clinically significant sleep apnoea

How to read a PSG

• A hypopnea is a reduction in ventilation by at least 50% that also results in a decrease of the O2 saturation by 4% or more (shallow breathing that results in desaturation).

• For some of our patients we are the first Doctor to go over the baseline sleep study with them.

How to read a PSG & what I say in clinic

• O2 Saturation: What is the O2 saturation nadir (lowest point), and how much time did the patient spend with an O2 saturation below 90%?

• This is a pretty obvious one to us as to why it is important. However, most patients will not realize what the O2 saturation means.

• Blood O2 levels, should be above 95% most of the time.

• If they were in a hospital and their O2 level went below 90, alarms would go off!

• Then tell them that their O2 level dropped to a low of X and was below 90 X% of the night

PSG interpretation

• Mild OSA:

AHI 1 – 4/hr

• Moderate OSA:

AHI 5 - 9/hr

• Severe OSA:

AHI > 10/hour

AHI: Apnoea-Hypopnea Index

Overnight Oximetry

• Easy to do & Inexpensive

• High positive predictive value

• BUT a normal/inconclusive result doesn’t rule out OSA

• Pre-op overnight SpO2 nadir <80% is associated with increased risk of postop. Complications (need HDU availble)

Interpreting Overnight Oximetry

How to read overnight oximetry

• Periodic clusters of desaturation on continuous overnight recording of oxygen saturation with 3 or more desaturations 90% has been demonstrated to have a 97% positive predictive value for OSA in otherwise healthy children

McGill Oximetry Score

Tonsillectomy and Adenoidectomy in Children with Sleep Related Breathing Disorders

• Consensus statement of a UK multidisciplinary working party Issued September 2008, reviewed July 2010

• Children with severe OSA or significant co-morbidity must be referred for preoperative paediatric respiratory assessment; these children will usually require surgical management in a paediatric centre with direct and immediate access to PHDU and PICU.

Indications for paediatric respiratory investigations

• Diagnosis of OSA unclear or inconsistent

• Age <2 years

• Weight <15kg

• Down’s syndrome

• Cerebral palsy

• Hypotonia or neuromuscular disorders

• Craniofacial anomalies

• Mucopolysaccharidosis

• Obesity (BMI >2.5SDS or >99th centile for age and gender)

• Significant comorbidity such as congenital heart disease, chronic lung disease

• Residual symptoms after AT

Dilemma

• Good history for OSA but no sleep study

• Delay?

• 6 month wait for sleep study

Postoperative outcomes

• Airway obstruction is not relieved immediately after surgery in children undergoing adenotonsillectomy for severe OSA.

• This is mainly due to oedema and swelling at the operation site, which improves in the first 24-48hours after surgery

• Nixon GM et al. Pediatric Pulmonology 2005

Postoperative outcomes

• The incidence of respiratory complications in patients with OSA is as high as 27%.

• Abnormal ventilatory responses to hypoxaemia and hypercapnia often persist during the immediate postoperative period.

• Leong et al. Morbidity after adenotonsillectomy for paediatric obstructive sleep apnoea syndrome: waking up to a pragmatic approach. J Laryngol Otol 2007

• Strauss et al. Ventilatory response to CO2in children with obstructive sleep apnea from adenotonsillar hypertrophy. Anesth Analg 1999

• Kerbl et al. Persistent hypercapnia in children after treatment of obstructive sleep apnea syndrome by adenotonsillectomy. Wien KlinWochenschr 2001

A retrospective analysis of 4092 consecutive patients undergoing tonsillectomy over a two-year period.

The Laryngoscope 2013

• 7.2% experienced desaturations (defined as sustained saturations <90%) in the first 24 hours postoperatively (mean nadir, 78.7%)

• OSA

• Trisomy 21

• Obesity

• Cardiac disease,

• Neurologic diagnosis

• Pulmonary disease

OSA & Analgesia

Children with pre op SpO2 nadir of < 85%

Post adenotonsillectomy required half the total analgesic morphine dose compared with children in pre op >85% group

Brown K A, et al Anesthesiology 2004

Postoperative outcomes

• ASA Closed Claims Project and the USA Society for Pediatric Anesthesia. Serious complications after tonsillectomy :

• Death or neurological injury were reported secondary to postoperative respiratory events.

• A significant number were preventable had the child been cared for in a medical setting with an appropriate level of observation and monitoring.

• More than half of these children carried a diagnosis of OSA.• “Tonsillectomy related malpractice settlements occur against

anesthesiologists more commonly than against surgeons and settle for 5 fold larger awards.”

Cote CJ et al. Death or neurologic injury after tonsillectomy in children with a focus on obstructive sleep apnea: Houston, we have a problem! Anesth Analg 2013

Goldman JL et al. Mortality and major morbidity after tonsillectomy: etiologic factors and strategies for prevention. Laryngoscope 2013

Post op complications

• Rates of respiratory complications range from 6.4% to 27%

• Depend on age, severity of OSA, and comorbidities. • Children < 3-yr-of-age have twice the risk of children

who are 3–6 yr of age.• Children with OSA had a 23% rate of respiratory

difficulties after adenotonsillectomy. • Pantino M et al Obstructive sleep apnoea in children:

perioperative considerations Br. J. Anaesth. (2013)

Increased risk of adverse events in childrenwith URTI

URTI related

• Fever (>38 C)

• Purulent and copious secretions

• Productive cough

• Malaise, lethargy, decreased appetite

• Lower respiratory tract signs

Child factors

• Age <1 year

• History of prematurity

• Sickle cell disease

• History of snoring

• History of reactive airway disease (asthma)

• Parental smoking

Anaesthesia and surgical factors

• Airway instrumentation (endotracheal tube (ETT) > laryngeal mask airway (LMA) > face mask)

• Airway surgery

• Inhalational induction

• Method of endotracheal extubation (deep > awake)

• Major surgery

• Anaesthetist with limited paediatric experience

URTI

Risk assessment for respiratory complications in paediatric anaesthesia: a prospective cohort studyHabre et alThe Lancet, Volume 376, Issue 9743, Pages 773 - 783,4 September 2010

• 9297 questionnaires were available for analysis.• A positive respiratory history (nocturnal dry

cough, wheezing during exercise, wheezing more than three times in the past 12 months, or a history of present or past eczema) was associated with an increased risk for:

• bronchospasm (relative risk [RR] 8·46, 95% CI 6·18—11·59; p<0·0001)

• laryngospasm (4·13, 3·37—5·08; p<0·0001)• perioperative cough, desaturation or airway

obstruction (3·05, 2·76—3·37; p<0·0001).

Risk assessment for respiratory complications in paediatric anaesthesia: a prospective cohort studyHabre et alThe Lancet, Volume 376, Issue 9743, Pages 773 - 783,4 September 2010

• Upper respiratory tract infection was associated with an increased risk for perioperative respiratory adverse events (RR 2·05, 95% CI 1·82—2·31; p<0·0001)

Risk assessment for respiratory complications in paediatric anaesthesia: a prospective cohort studyHabre et alThe Lancet, Volume 376, Issue 9743, Pages 773 - 783,4 September 2010

• Risk was lower with intravenous induction compared with inhalational induction (p<0·0001) post URTI.

• Airway management by a specialist paediatric anaesthetist compared with a registrar (all p<0·0001), and use of LMA compared with tracheal intubation (all p<0·0001) post URTI

Summary

Low risk - Majority of children

Day case (if done early in day)

Moderate risk

Facilities/staff to administer CPAP Overnight oximetry: HDU

High risk

Very few need ICU

A parent’s perspective

• “Before the operation, my child had loud snoring, and even with the television on you could hear it. I could tell something was not right. During the day she seemed to have a cold all the time. She had an operation to remove her tonsils and adenoids. The results from this were fantastic. Her symptoms vanished after the operation. She now makes no noise when she sleeps and seems to have a better night’s sleep. During the day she seems happier and more settled than before the operation.”