Automated emergency ventilation devices in a simulated unprotected airway.
BACKGROUND
Automated ventilation devices are becoming more popular for emergency ventilation, but there is still not much experience concerning the optimal ventilation mode.


METHODS
In a bench model representing a non-intubated patient in respiratory and cardiac arrest, we compared a pressure-cycled with a time- and volume-cycled automated ventilation device in their completely automated modes. The main study endpoints were inspiratory time, respiratory rate, stomach inflation, and lung tidal volumes.


RESULTS
The pressure-cycled device inspired for 6.7 s in the respiratory arrest setting (respiratory rate 5.6/min), and never reached its closing pressure in the cardiac arrest setting (respiratory rate 1 breath/min). The time- and volume-cycled device inspired in both settings for 1.7 s (respiratory rate 13 breaths/min). In the respiratory arrest setting, mask leakage was 620 ± 20 mL for the pressure-cycled device vs. 290 ± 10 mL for the time- and volume-cycled device (p < 0.0001); lung tidal volume was 1080 ± 50 mL vs. 490 ± 20 mL, respectively (p < 0.0001); and there was no stomach inflation for either device. In the cardiac arrest setting, pressure-cycled device mask leakage was 5460 ± 60 mL vs. 240 ± 20 mL (p < 0.0001) for the time- and volume-cycled device (p < 0.0001); stomach inflation was 13,100 ± 100 mL vs. 90 ± 10 mL, respectively (p < 0.0001); and lung tidal volume 740 ± 60 mL vs. 420 ± 20 mL, respectively (p < 0.0001).


CONCLUSIONS
In a simulated respiratory arrest setting, ventilation with an automated pressure-cycled ventilation device resulted in lower respiratory frequency and larger tidal volumes compared to a time- and volume-cycled device. In a simulated cardiac arrest setting, ventilation with an automated pressure-cycled ventilation device, but not a time- and volume-cycled device, resulted in continuous gastric insufflation.
Herff
Holger
H
Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
Schmittinger
Christian A
CA
von Goedecke
Achim
A
Paal
Peter
P
Mitterlechner
Thomas
T
Lindner
Karl H
KH
Wenzel
Volker
V
D000402:Airway Obstruction / Q000628:therapy; D016887:Cardiopulmonary Resuscitation / Q000379:methods; D004630:Emergencies; D004632:Emergency Medical Services; D006801:Humans; D008954:Models, Biological; D012121:Respiration, Artificial / Q000295:instrumentation*; D015656:Respiratory Mechanics / Q000502:physiology; D013990:Tidal Volume