Effect of mild hypercapnia on outcome and histological injury in a porcine post cardiac arrest model

Aim of the study: To evaluate in an established porcine post cardiac arrest model the effect of a mild hypercapnic ventilatory strategy on outcome. Methods: The left anterior descending coronary artery was occluded in 14 pigs and ventricular fibrillation induced and left untreated for 12 min. Cardiopulmonary resuscitation was performed for 5 min prior to defibrillation. After resuscitation, pigs were assigned to either normocapnic (end-tidal carbon dioxide (EtCO2) target: 35-40 mmHg) or hypercapnic ventilation (EtCO2 45-50 mmHg). Hemodynamics was invasively measured and EtCO2 was monitored with an infrared capnometer. Blood gas analysis, serum neuron-specific enolase (NSE) and high sensitive cardiac troponin T (hs-cTnT) were assessed. Survival and functional recovery were evaluated up to 96 h. Results: Twelve pigs were successfully resuscitated and eight survived up to 96 h, with animals in the hypercapnic group showing trend towards a longer survival. EtCO2 and arterial partial pressure of CO2 were higher in the hypercapnic group compared to the normocapnic one (p