Real-time tidal volume feedback guides optimal ventilation during simulated CPR

Abstract

Purpose: We performed this study to investigate whether real-time tidal volume feedback increases optimal ventilation and decreases hyperventilation during manikin-simulated cardiopulmonary resuscitation (CPR). Basic procedures: We developed a new real-time tidal volume monitoring device (TVD) which estimated tidal volume in real time using a magnetic flowmeter. The TVD was validated with a volume-controlled mechanical ventilator with various tidal volumes. We conducted a randomized, crossover, manikin-simulation study in which 14 participants were randomly divided into a control (without tidal volume feedback, n = 7) and a TVD group (with real-time tidal volume feedback, n = 7) and underwent manikin simulation. The optimal ventilation was defined as 420-490 mL of tidal volumes for a 70-kg adult manikin. After 2 weeks of the washout period, the simulation was repeated via the participants' crossover. Main findings: In the validation study, 97.6% and 100% of the difference ratios in tidal volumes between the mechanical ventilator and TVD were within 1.5% and 2.5%, respectively. During manikin-simulated CPR, TVD use increased the proportion of optimal ventilation per person. Its median values (range) of the control group and the TVD group were 37.5% (0.0-65.0) and 87.5% (65.0-100.0), respectively, P < .001). TVD use also decreased hyperventilation. The proportions of hyperventilation in the control group and the TVD group were 25.0% vs 8.9%, respectively (P < .001). Principal conclusions: Real-time tidal volume feedback using the new TVD guided the rescuers to provide optimal ventilation and to avoid hyperventilation during manikin-simulated CPR.