Postoperative cardiorespiratory complications and continuous positive airway pressure efficacy in obese patients undergoing noncardiac surgery

BACKGROUND AND AIMS: One in six Singaporeans has obstructive sleep apnoea (OSA) due to obesity compounded by inherent craniofacial features. We assessed the incidence of cardiopulmonary complications and the effectiveness of continuous positive airway pressure (CPAP) therapy in minimising such complications within an obese population. METHODS: A retrospective study of elective noncardiac surgical patients with a body mass index ≥32 kg/m(2) was conducted. Patients at moderate to severe risk of OSA were offered CPAP therapy. CPAP therapy adherence, postoperative complications, length of hospital stay, and type of anaesthesia were analysed. RESULTS: In total, 1400 patients comprising 174 with low risk of OSA (L-OSA) and 1226 with moderate to high risk of OSA were included. Of these, 332 were started on CPAP therapy (C-OSA) while 894 declined CPAP use (R-OSA). There were 10 (0.05%) cardiac events – one (0.6%) in the L-OSA group, six (0.6%) in the R-OSA group and three (0.9%) in the C-OSA group. There were 37 (2.6%) respiratory events – 2 (1.1%) in the L-OSA group, 23 (2.6%) in the R-OSA group, and 12 (3.6%) in the C-OSA group. Multivariate analysis showed no statistical significance in CPAP therapy minimising cardiac (P = 0.147) and respiratory (P = 0.255) complications, when analysed by intention-to-treat. CPAP therapy adherence was 13.6 and 10.2% pre- and postoperatively, respectively. When analysed per protocol, none of the nine patients compliant with both pre- and postoperative CPAP therapy developed cardiopulmonary complications. CONCLUSIONS: Amongst patients with moderate to severe risk of OSA, those who were compliant to perioperative CPAP therapy demonstrated a reduction in cardiopulmonary complications.