Paediatric sleep investigations: polysomnography, sleep-study interpretation and MSLT — formative SAQs

SAQ 1 — Reading the polysomnogram of a snoring preschooler (10 marks, 15 minutes)

A four-year-old girl snores nightly with witnessed pauses and gasping, sleeps restlessly and is inattentive at kindergarten. She has large tonsils and her weight is on the tenth centile. An attended overnight polysomnogram reports an obstructive apnoea-hypopnoea index of 9 events per hour, a central apnoea index of 0.3, an oxygen saturation nadir of 84 per cent, and a peak carbon dioxide of 46 mmHg, with adequate total sleep and rapid-eye-movement sleep. ^[1]

a) Interpret this report: classify the predominant event type and grade the severity, stating why paediatric rather than adult thresholds are used. (4 marks) ^{[6] [2]}

b) What single channel distinguishes an obstructive from a central event, and how does it do so? (3 marks) ^[7]

c) What is your first-line treatment and what follow-up would you plan? (3 marks) ^{[1] [2]}