Abstract 321: Manual vs Automated Ventilation During Automated Head-Up Cardiopulmonary Resuscitation in a Porcine Model

Abstract

Background: The efficacy of mechanical ventilation during CPR with the combination of active compression-decompression, an impedance threshold device, and head-up positioning, collectively termed automated head-up (AHUP)-CPR, is unknown. Hypothesis: Hemodynamic and ventilatory parameters will be similar with manual bag ventilation (MBV) versus automated bag ventilation (ABV) during AHUP-CPR in a porcine model of cardiac arrest. Aim: Assess the proof-of-concept that ABV is safe and effective during AHUP-CPR. Methods: Nine male and female swine (~40 kg) were anesthetized and ventilated. VF was induced and left untreated for 8 min. AHUP-CPR was performed at 105 compressions/min for 7 min using MBV, followed by 6 min using an automated mechanical bag compressor to deliver 10ml/kg of tidal volume (TV) over 1 sec at 10 breaths/min. Pigs were randomized during ABV to a synchronized (Sync) breath delivered at the start of decompression or an asynchronous (Async) breath. Cerebral perfusion pressure, coronary perfusion pressure, end-tidal CO2, intracranial pressure, esophageal intrathoracic pressure, peak airway pressure (PAP), inspiratory and expiratory TVs as well as arterial blood gases were continuously measured. Values (mean ± SD) were compared by paired and unpaired student’s t-tests with a Bonferroni correction. Results: Parameters during the last minute of MBV and ABV are summarized in the table. No significant differences were observed in hemodynamic and ventilatory parameters, except for PAP and pO2 values which were significantly lower with MBV. No significant differences were also observed between the Sync and Async ABV modes. Conclusion: Manual and mechanical ventilation resulted in overall similar physiological effects. The clinical relevance of the observed significant differences in PAP and pO2 is unclear. Additional studies are warranted to further assess the safety and effectiveness of mechanical ventilation during AHUP-CPR.