Effect of gasps to hemodynamics during cardiopulmonary resuscitation in a porcine model of prolonged cardiac arrest

Abstract

Objective Gasp was defined as a pathology respiration during cardiac arrest. This study was to investigate its effect on hemodynamics during CPR. Method Twelve domestic pigs, weighening (30 ± 1) kg,were anaesthetized. After tracheal intubation and mechanical ventilation, continuous respiratory variables were recorded. An artery catheter was inserted for reference blood samples and measuring aortic artery pressure (AOP).Right atrial pressure (RAP) and cardiac output (CO) were detected by Swan-Ganz catheter. Ventricular fibrillation (VF) was induced by programmed electrical stimulation instruments. After 4 minutes untreated VF, standard 30:2 CPR was done for 12 minutes and the parameters were recorded. Results pH, PaCO2 and lactic acid increased and PaO2 decreased progressively during CPR, whereas PaO2 was up to 50mmHg during the whole protocol. Gasps were observed in 10 animals, but weaken gradually; the left 2 animals with no gasp did not restore of spontaneous circulation (ROSC). Standard CPR could produce passive ventilation more than dead space (VD), but its tidal volume decreased gradually, which led to the percentage of rescue ventilation increased progressively. Positive correlations were found between CO, coronary perfusion pressure (CPP) and minute ventilation of gasps (MVg) (r was 0.736 and 0.721 respectively, both P ＜0.01); negative correlation were found between RAP and MVg (r= -0. 744, P ＜ 0.01). Conclusions Standard CPR could maintain 12 minutes oxygenation of body; compressions could produce enough passive ventilation more than VD; gasps were benefit to ROSC by increasing CO, CPP and decreasing RAP. Key words: Gasp; Ventricular fibrillation; Cardiopulmonary resuscitation; Cardiac output; Coronary perfusion pressure; Swine