[Emergency airway management-- comparison of various strategies in an unsecured airway]

Gastric inflation and regurgitation of stomach contents are major hazards of bag-valve-mask ventilation in an emergency. The purpose of our study was to determine lung ventilation and gastric inflation when using the bag-valve-face mask, laryngeal mask, and combitube with different sizes of self-inflating bags (max. volume: 700, 1100, 1500 ml).

Twenty-six training emergency doctors without prior extensive training in emergency airway management volunteered for our study and ventilated a bench model simulating an unintubated respiratory arrest patient with bag-valve-face mask, laryngeal mask, and combitube using paediatric, medium size, and adult self-inflating bags. Lung and gastric tidal volume, as well as lung and gastric peak airway pressure were measured with respiratory monitors and a pneumotachometer.

When using either the combitube or the laryngeal mask, the paediatric vs. medium-size and adult self-inflating bag resulted in significantly (P < .001) lower mean +/- SEM lung tidal volumes (328 +/- 34 vs. 626 +/- 65 vs. 654 +/- 69 ml; and 368 +/- 30 vs. 532 +/- 48 vs. 692 +/- 67 ml, respectively). No gastric inflation occurred with the combitube, while gastric inflation was comparably low when using the laryngeal mask with either ventilation bag (3 +/- 2 vs. 7 +/- 4 vs. 6 +/- 3 ml; P = NS). The paediatric vs. medium-size and adult self-inflating bag in combination with the bag-valve-face mask resulted in comparable lung tidal volumes (250 +/- 23 vs. 313 +/- 24 vs. 282 +/- 38 ml; P = NS); but significantly (P < .01) lower gastric tidal volumes (147 +/- 23 vs. 206 +/- 24 vs. 267 +/- 23 ml).

Both the laryngeal mask and the combitube proved to be valid alternatives for the bag-valve-face mask in our experimental model. The medium size self-inflating bag seems to be adequate when using either the laryngeal mask or the combitube.