The Adequacy of a Conventional Mechanical Ventilator as a Ventilation Method during Cardiopulmonary Resuscitation: A Manikin Study

Abstract

Background: We conducted this study to verify whether a mechanical ventilator is adequate for cardiopulmonary resuscitation (CPR). Methods: A self-inflating bag resuscitator and a mechanical ventilator were used to test two experimental models: Model 1 (CPR manikin without chest compression) and Model 2 (CPR manikin with chest compression). Model 2 was divided into three subgroups according to ventilator pressure limits (Plimit). The self-inflating bag resuscitator was set with a ventilation rate of 10 breaths/min with the volume-marked bag-valve procedure. The mode of the mechanical ventilator was set as follows: volume-controlled mandatory ventilation of tidal volume (Vt) 600 mL, an inspiration time of 1.2 seconds, a constant flow pattern, a ventilation rate of 10 breaths/ minute, a positive end expiratory pressure of 3 cmH2O and a maximum trigger limit. Peak airway pressure (Ppeak) and Vt were measured by a flow analyzer. Ventilation adequacy was determined at a Vt range of 400-600 mL with a Ppeak of ≤ 50 cmH2O. Results: In Model 1, Vt and Ppeak were in the appropriate range in the ventilation equipments. In Model 2, for the self-inflating bag resuscitator, the adequate Vt and Ppeak levels were 17%, and the Ppeak adequacy was 20% and the Vt was 65%. For the mechanical ventilator, the adequate Vt and Ppeak levels were 85%; the Ppeak adequacy was 85%; and the Vt adequacy was 100% at 60 cmH2O of Plimit. Conclusions: In a manikin model, a mechanical ventilator was superior to self-inflating bag resuscitator for maintaining adequate ventilation during chest compression.