A special face mask with integrated angle meter to optimize the head position for bag-valve-mask ventilation—a prospective simulated proof-of-concept study

The supine position in unconscious patients resulted in the tongue falling back because of the loss of muscle tension which obstructed the upper airway. The head reclination opened the airway, however unexperienced rescuers faced difficulties in performing bag-valve-mask ventilation as it was hard to detect the optimal head position for opening the airway. The bag-valve-mask ventilation could be optimized if it indicated an optimized head angle to the rescuer. A digital sensor was attached to the face mask for measuring the degree of head reclination. Moreover, the face mask was equipped with an airway trainer and sealed via adhesive tape. The airway trainer was connected to a test lung and ventilated through pressure-controlled standard anesthesia machine (Pmax = 10 mbar, Positive End Expiratory Pressure (PEEP) = 0 mbar, f = 12/min). The head of airway manikin was tilted to 42 degrees starting from neutral position with a gradient of 2 degrees. The primary endpoint was the correlation of preset angles and digitally measured head position angles via the mask. In addition, the tidal and minute volumes were evaluated based on the head reclination. The preset and the digitally measured head position angles depicted correlation (R2 = 0.9895855684; p < 0.001). The tidal volume was 150 mL in head position angle of <10 degrees, 200 mL at 18 degrees, 450 mL at 25 degrees, and it levelled with about 500 mL at 30 degrees. In conclusion, digital head position angle was measured to detect the correct head position. A signal in the face mask could indicate the optimized head position to the first respondents or inexperienced rescuers in emergency ventilation.

Airway obstruction; Emergency ventilation; Face mask; Head reclination; Unprotected airway; Ventilation

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