Introduction: Chest compression and ventilation during CPR may increase risk of regurgitation and aspiration. Pulmonary aspiration is a clinically relevant endpoint as it is associated with significant mortality. There is limited data comparing the impact of continuous and interrupted chest compression during CPR on risk of regurgitation and aspiration. Thus, we aim to obtain a preliminary estimate of incidences of regurgitation and aspiration of continuous versus interrupted chest compression using a cadaver model.
Hypothesis: Interrupted chest compression, compared with continuous chest compression during CPR, is associated with a lower risk of regurgitation and aspiration.
Methods: In a cross-over design, 10 cadavers (BMI<45 kg/m2) with no airway pathologies were studied. Cadavers were suctioned for pre-existing stomach contents, applied the Lucas CPR board (Physio Control, Redmond, WA) and a King LTS-D supraglottic device was placed. Stomach content was simulated by methylene-blue and barium sulfate for the first and second interventions, respectively. Cadavers were randomized to receive CPR starting with either 1) Continuous compressions (rate of 100/min), while ventilating at rate of 10/min or 2) Interrupted compressions, while ventilating at a rate of 30:2. Each CPR session lasted 14 minutes. Stomach was properly suctioned prior to the next intervention to avoid cross-over contamination. Regurgitation and/or aspiration was assessed by bronchoscopy (methylene blue) and radiography (barium sulfate).
Results: The incidence of regurgitation was 100% for continuous chest compression, while that of interrupted chest compression was 70%. The incidence of aspiration of continuous chest compression was 50% while that of interrupted chest compression was 30%.
Conclusions: In conclusion, interrupted chest compression was associated with 20% less incidence of aspiration compared to continuous compression during CPR in our cadaver model. Our study is limited by its small size and use of cadavers, but nonetheless estimated incidences of pulmonary aspiration by CPR method to provide insight for future studies.