Developing a special face mask with an angle meter to optimize the head position while performing bag–valve–mask ventilation—a prospective simulated proof-of-concept study

Abstract

Abstract Background In unconscious patients in the supine position, the loss of soft tissue tension results in obstruction of the upper airway. Unexperienced rescuers may be unable to perform efficient bag–valve–mask ventilation due to difficulties in detecting the optimal head position to open the airway. If the ventilation mask were to indicate an optimized head position to the rescuer, bag–valve–mask ventilation could possibly be optimized. Methods A digital sensor was attached to a face mask to measure the degree of head reclination. We attached this face mask to an airway trainer and sealed the mask to its face with tape; the airway trainer was connected to a test lung and ventilated in a pressure-controlled mode by a standard anesthesia machine (Pmax 10 mbar, PEEP 0 mbar, F 12/min). Its head was extended starting from the neutral position to 42 degrees in steps of 2 degrees. The primary endpoints were the correlation of preset angles and our face mask’s digitally measured head position angles. We further evaluated the tidal and minute ventilation volume depending on head reclination. Results The preset head position angles correlated significantly (R2 = 0.9895855684; P<.001) with the digitally measured head position angles. In head position angles <10 degrees, the tidal volume was 150 mL; at 18 degrees, it was 200 mL; at 25 degrees, it was 450 mL; and it levelled off at 30 degrees with about 500 mL. Conclusion Digital head position angle measurement correctly detected the head position in this study. A signal in a face mask could be a helpful tool to indicate to first responders or relatively inexperienced rescuers the optimized head position during emergency ventilation.