Correlation of Bedside Airway Screening Tests With Airway Obstruction During Drug-Induced Sleep Endoscopy

Obstructive sleep apnoea hypopnoea syndrome associated with obesity poses major perioperative airway challenge. Drug-induced sleep endoscopy (DISE), is a real-time upper airway flexible fiberoptic nasoendoscopy in awake and sedation/anaesthesia-induced sleep. The aim of current study was to assess the correlation of bedside airway screening tests with level of obstruction during DISE.

Study was performed in endoscopy suite. Parameters calculated in 40 study group patients were Berlin questionnaire responses, Apnea hypopnea index (AHI), interincisor distance, Mallampati classification (MPC), neck circumference (NC), thyromental distance (TMD), NC/TMD ratio, sternomental distance (SMD), upper lip bite test, lateral cephalometry derived gonial angle and mentohyoid distance (MHD), Muller’s manoeuvre during awake nasoendoscopy, Croft–Pringle grade of airway obstruction during DISE and effect of jaw thrust.

All patients were American Society of Anesthesiologists physical status 1 and 2 with AHI > 30. Positive responses to Berlin questionnaire, body mass index and AHI increased with increasing grade of DISE. DISE grades 1–5 were observed in 0% (0), 5% (2), 37.5% (15), 27.5% (11) and 30% (12) patients respectively. Muller’s manoeuvre showed lateral wall collapse in 40% (16) patients and concentric collapse in 40% (16) patients. Airway patency improved with jaw thrust in 60% (24) patients. Significant association of DISE was found with MPC (p = 0.028), TMD (p = 0.003), MHD (p = 0.008) and NC/TMD ratio (p = 0.002), effect of Muller’s manoeuvre (p =0.002), and effect of jaw thrust (p = 0.000).

Bedside screening tests MPC, TMD, NC/TMD ratio and MHD correlate significantly with level of obstruction during DISE.