Preoperative predictors of difficult intubation in patients with obstructive sleep apnea syndrome

Purpose: It has been speculated that the severity of obstructive sleep apnea syndrome (OSAS) is related to difficult intubation. However, this has not been confirmed in OSAS patients. Thus, we undertook a retrospective study to assess this relationship in patients who had undergone uvulopalatopharyngoplasty (UPPP) surgery for OSAS. Methods: A retrospective case-control study was undertaken following approval from the Institutional Review Board on human studies. The data from 90 patients with a polysomnograph-confirmed diagnosis of OSAS, who had undergone UPPP surgery under general anesthesia, were used to evaluate the apnea-hypopnea index (AHI), the preoperative lowest arterial saturation, the occurrence of difficult intubation as assessed by the operator intubation difficulty scale score, extubation time, lowest arterial saturation in postanesthesia care unit, and length of stay in postanesthesia care unit. We compared OSAS patients with 90 age and sex-matched control patients with respect to the prevalence of difficult intubation. Results: The prevalence of difficult intubation was higher in the OSAS group than in the control group (16.7% vs 3.3%, P = 0.003). When evaluating the OSAS group according to the occurrence of difficult intubation, AHI was significantly higher in the difficult intubation subgroup (67.4 +/- 22.5 vs 49.9 +/- 28.0, P = 0.026), and patients with an AHI >= 40 showed a significantly higher prevalence of difficult intubation. Conclusion: This study shows that the occurrence of difficult intubation can be predicted using AHI in patients who undergo UPPP surgery for OSAS.