A pilot study of upper airway management using a remote-controlled artificial muscle device during propofol anesthesia

Abstract Study objective To test the hypothesis that the jaw closure using a pneumatic actuator device affect airway collapsibility and resistance during propofol anesthesia. Design Prospective, randomized study. Setting University-affiliated hospital. Patients Six male subjects were included in the present study. Intervention We used pressure-flow relationships to evaluate critical closing pressure (P CRIT ) and upper airway resistance in different conditions of body and head position. Anesthesia was induced and maintained with a propofol infusion, targeting a constant blood concentration of 1.5 to 2.0μg/mL to establish an adequate depth of anesthesia, with patients breathing spontaneously through a nasal mask. An air-inflatable pneumatic actuator was used to achieve jaw closure. Nasal mask pressure was intermittently reduced to evaluate upper airway collapsibility (passive P CRIT ) and upstream resistance under 4 different conditions: (1) neutral occlusion at 0-cm head elevation (baseline), (2) jaw closure at 0-cm head elevation, (3) neutral occlusion at 6-cm head elevation, and (4) jaw closure at 6-cm head elevation. P CRIT and upstream resistance under each condition were compared using 1-way analysis of variance. P Measurements The pressure and inspiratory flow at the subjects' nose mask were recorded. Polysomonographic parameters (electroencephalograms, electrooculograms, submental electromyograms, and plethysmogram) were also recorded. Main results The combination of 6-cm head elevation with jaw closure using the pneumatic actuator decreased upper airway collapsibility (P CRIT ≈−3.0 cm H 2 O) compared to the baseline position (P CRIT ≈−1.2 cm H 2 O; P =.0003). Conclusion We demonstrated that jaw closure using an air-inflatable pneumatic actuator device can produce substantial decreases in upper airway collapsibility and maintain upper airway patency during propofol anesthesia.