Pharyngeal patency in response to advancement of the mandible in obese anesthetized persons

Background: During anesthesia in humans, anterior displacement of the mandible is often helpful to relieve airway obstruction. However, it appears to be less useful in obese patients, The authors tested the possibility that obesity limits the effectiveness of the maneuver. Methods: Total muscle paralysis was induced under general anesthesia in a group of obese persons (n = 9; body mass index, 32 +/- 3 kg(-2)) and in a group of nonobese persons (n = 9; body mas index, 21 +/- 2 kg(-2)). Nocturnal oximetry confirmed that none of them had sleep-disordered breathing, The cross-sectional area of the pharynx was measured endoscopically at different static airway pressures. A static pressure-area plot allowed assessment of the mechanical properties of the pharynx. The influence of mandibular advancement on airway patency was assessed by comparing the static pressure-area relation with and without the maneuver in obese and nonobese persons. Results: Mandibular advancement increased the retroglossal area at a given pharyngeal pressure, and mandibular advancement increased the retropalatal area in nonobese but not in obese persons at a given pharyngeal pressure. Conclusion: Mandibular advancement did not improve the retropalatal airway in obese persons.