A Remote-Controlled Airbag Device Can Improve Upper Airway Collapsibility by Producing Head Elevation With Jaw Closure in Normal Subjects Under Propofol Anesthesia

Continuous maintenance of an appropriate position of the mandible and head purely by manual manipulation is difficult, although the maneuver can restore airway patency during sleep and anesthesia. The aim of this paper was to examine the effect of head elevation with jaw closure using a remote-controlled airbag device, such as the airbag system, on passive upper airway collapsibility during propofol anesthesia. Seven male subjects were studied. Propofol infusion was used for anesthesia induction and maintenance, with a target blood propofol concentration of 1.5-2 μg/ml. Nasal mask pressure (P_N) was intermittently reduced to evaluate upper airway collapsibility (passive P_CRIT) and upstream resistance (R_US) at three different head and jaw positions, jaw opening position in the supine position, jaw opening position in the sniffing position with 6-cm head elevation, and jaw closure at a 6-cm height sniffing position. The 6-cm height sniffing position with jaw closure was achieved by an airbag device that was attached to the subject's head-like headgear. Patient demographics, (P_CRIT) and (R_US) in each condition were compared using one-way ANOVA with a post hoc Tukey test. (P <0.05) was considered significant. We also confirmed the effects of our airbag device on improvement of upper airway collapsibility in three obstructive sleep apnea patients in a clinical study. The combination of 6-cm head elevation with jaw closure using the air-inflatable robotic airbag system decreased upper airway collapsibility ((P_CRIT ∼ -3.4)-cm H₂O) compared with the baseline position (P_CRIT ∼ -0.8-cm H₂O, P = 0.0001). In the clinical study, there was improvement of upper airway obstruction in sleep apnea patients, including decreased apnea and hypopnea duration and increased the lowest level of oxygen saturation. We demonstrated that establishment of head elevation with jaw closure achieved by a remote-controlled airbag device using an inflatable airbag system can produce substantial decreases in upper airway collapsibility and maintain upper airway patency during propofol anesthesia and sleep.