Introduction

Obstructive Sleep Apnoea (OSA) has an incidence of 1.5 - 3 % in children ₁ . It is commonest between the ages of 3 - 7 years although it can occur at any time after 4 months of age. The male: female ratio is 2:1. 85% of sleep apnoeas in children are obstructive in origin ₁ . About 10% are central and 5% mixed ₁ . Common symptoms include snoring, noisy breathing, observed apnoeas and day time somnolence. Polysomnography is used to assess the severity of the disease ₂ . OSA is defined as an oxygen saturation drop of more than 2% associated with an apnoea of more than 10 seconds and a decrease in airflow of at least 50% ₂ . A breathing related arousal (BRA) is defined as a drop in airflow of more than 30% with a change in breathing pattern and an arousal and at least a 1% drop in oxygen saturation. Respiratory disturbance index (RDI) is the sum of these two (OSA & BRA) per hour. A RDI greater than 10 is a risk factor for postoperative complications. OSAS is obstructive sleep apnoea accompanied by day time symptoms like excessive somnolence. Associated risk factors include young age (< 3years), failure to thrive, cor-pulmonale, neuromotor disease, craniofacial abnormalities, chromosomal abnormalities, history of prematurity, recent respiratory infections, obesity etc ₃ . Postoperative paediatric intensive care unit (PICU) admission may be required in these patients. Polysomnography is a gold standard investigation in children with OSA. It is useful for accurate diagnosis and severity grading ₄ . Nocturnal pulse oximetry is another useful diagnostic tool.

Risks associated with the anaesthetic include difficult airway, difficult intubation,
hypoxia, cardiovascular instability, residual action of drugs used during anaesthesia,
and postoperative apnoeas.

Methods

The aim of this audit was to look at anaesthetic management of children with OSAS
in our hospital. The audit was registered with the hospital clinical audit committee and ethics committee approval was deemed not necessary. We retrospectively identified patients with OSAS who had an anaesthetic for any type of surgery or diagnostic scan from August 2006 to August 2007. Details of the demographic data, preoperative factors, intra-operative anaesthetic management, and postoperative care were collected from the anaesthetic chart, operative record, and patient notes.

Results

We identified 32 children with OSAS who had anaesthetic for surgery or diagnostic
scan in 1 year (August 2006-August 2007).

Preoperative factors

Age groups varied from 11 months - 5 years

Male /female ratio was 24 / 8.

Figure 1

Table 1: Case Distribution

Figure 2

Table 2: Diagnosis of OSAS by

Figure 3

Table 3: Diagnostic Criteria used

Complex congenital anomaly in association with OSAS was seen in 3 children and 1 required home continuous positive airway pressure (CPAP).

Intraoperative factors

There was even distribution between gas induction (17/ 32) and intravenous anaesthetic induction (15/ 32). Tracheal intubation was used for airway management in all patients. Fibreoptic bronchoscope was used for intubation in 1 patient with history of difficult intubation during previous anaesthetic. Grade 3 views on laryngoscopy were seen in 2 patients requiring anterior tracheal pressure and gum elastic bougie to achieve intubation.

Figure 4

Table 4: Laryngoscopy Grades (Cormack & Lehanne)

Opioid analgesics were used in 31/ 32 patients. Fentanyl and codeine were most commonly used opioids. No major intraoperative complications were encountered apart from transient oxygen desaturation in 2/ 32 patients.

Postoperative factors

Discussion

Difficult intubation is common in children with OSA. Every patient diagnosed with
OSAS or with clinical suspicion of OSAS, should be considered to have a difficult
airway, until proven otherwise and consequently has increased risk of anaesthesia.
The universal availability of investigations like Polysomnography is constrained by
resource and staffing issues. There are no guidelines for use of investigations like polysomnography in children with OSAS. Polysomnography is useful for risk stratification and its use is limited to OSA with associated high risk factors. Preoperative assessment should identify any high risk associations with OSAS. Difficult intubation trolley should be readily available in theatre. Opioids should be used with caution and regional analgesic techniques may be useful. Risk groups require PICU admission and intensive postoperative monitoring.

Support

Correspondence to

Sumant Shanbhag Anaesthetics Department Birmingham Children's Hospital Steelhouse lane Birmingham B4 6NH Email: sumant75@hotmail.com