Purpose: To determine the performance of two person CPR on an instrumented manikin by registered nurses using conventional bag valve mask (BVM) ventilation or the Impact Model 730 automatic transport ventilator (Impact 730, Impact Instrumentation, Inc., West Caldwell, NJ) in CPR mode using a face mask.
Design: Randomized crossover quasi-experimental.
Setting: Laboratory simulation.
Subjects: Twenty-eight registered nurses trained in performing adult cardiopulmonary resuscitation (CPR).
Interventions: Basic Life Support was provided by subjects using a conventional bag valve mask (BVM) ventilation or mask ventilation with an automatic transport ventilator, the Impact 730, which incorporates a metronome to facilitate chest compression timing. Subjects alternated performing 4min of CPR using the BVM or Impact 730 to deliver breaths with a mask while the other subject performed compressions.
Measurements and main results: Flow, volume and pressure were measured using a pneumotachograph and pressure transducer, and ease of use was measured using a 10cm visual analogue scale. There was no statistical or clinical difference between the actual and recommended tidal lung volume (mean+/-S.D.) delivered by the Impact 730 (-120.4+/-91.5ml) versus the BVM (-119.8+/-187.3+/-ml). Ventilation with the BVM resulted in more (137.7+/-143.9ml) air per breath passing through the simulated lower esophageal sphincter compared to the Impact 730 (14.0+/-16.8ml, p<0.05). The reduced mask leak per breath with the Impact 730 (176.1+/-98.3ml) compared to the BVM (367.6+/-337.7ml, p<0.05) is likely to have resulted from the subject being able to manage the mask with two rather than one hand and is reflected in the higher ease of use score on a 10cm visual analogue scale with the Impact 730 (8.06+/-1.35cm) versus the BVM (6.46+/-2.46cm, p<0.05). Subjects tended to deliver slightly more compressions and breaths when using the BVM.
Conclusion: Compared to the BVM, the Impact 730 is as effective, easier to use and limits the amount of gas entering the stomach when used during adult CPR in a simulated setting.