O015 Upper airway collapsibility measurement under anaesthesia in children: feasibility and utility in predicting perioperative respiratory adverse events

Abstract

Abstract Background Perioperative respiratory adverse events (PRAE) pose significant risk in paediatric anaesthesia, and identifying risk is vital. Perioperative measurement of pharyngeal closing pressure (PCLOSE) is a quick, objective method of assessing upper airway collapsibility that may identify PRAE risk. Aim To investigate if PCLOSE measurement is feasible and predictive of PRAE in children. Method Fifty-six children (1-8years, 34 male, without significant co-morbidities) underwent PCLOSE measurements immediately preceding (pre-PCLOSE) and following (post-PCLOSE) adenotonsillectomy. Measurement was performed under anaesthesia while breathing spontaneously in supine posture with head/jaw neutral. After application of a face mask, inspiratory flow was occluded with an associated decrease in mask/nasal pressure seen with each inspiratory effort. With airway collapse, a plateau developed in minimum pressure observed (= PCLOSE): less collapsible airways occluded at more negative pressures. PCLOSE was averaged over 5–6 sequential efforts, at least 3 times on each occasion. Results Both pre-and post-PCLOSE were successfully measured in 94.6% children without affecting procedure. Pre-PCLOSE and change in PCLOSE from pre- to post- were associated with an increased incidence of PRAE (Poisson regression coefficient 0.083(0.03) (mean, SE); p=0.0054 and 0.03(0.01); p=0.018, respectively). There was no significant association between post-PCLOSE and PRAE. The odd of PRAE occurrence during recovery was 1.5 times higher than in other phases. Conclusion This study demonstrated the feasibility of obtaining PCLOSE. A more collapsible airway before surgery and an increase in collapsibility with surgery were both associated with increased PRAE. PCLOSE measurement could be a valuable risk assessment tool for PRAE in children undergoing surgery.