Improved haemodynamics and restoration of spontaneous circulation with constant aortic occlusion during experimental cardiopulmonary resuscitation.

Continuous balloon occlusion of the descending aorta is an experimental method that may improve blood flow to the myocardium and the brain during cardiopulmonary resuscitation (CPR). The aim of the present investigation was to evaluate the effects of this intervention on haemodynamics and the frequency of restoration of spontaneous circulation. Ventricular fibrillation was induced in 39 anaesthetised piglets, followed by an 8-min non-intervention interval. In a haemodynamic study (n = 10), closed chest CPR was performed for 7 min before the intra-aortic balloon was inflated. This intervention increased mean arterial blood pressure by 20%, reduced cardiac output by 33%, increased coronary artery blood flow by 86%, and increased common carotid artery blood flow by 62%. All these changes were statistically significant. Administration of epinephrine further increased mean arterial blood pressure and coronary artery blood flow, while cardiac output and common carotid artery blood flow decreased. In a study of short-term survival, nine out of 13 animals (69%) in the balloon group and in three out of 13 animals (23%) in the control group had spontaneous circulation restored. The difference between these two proportions was 0.46, which was statistically significant with a 95% confidence interval from 0.12 to 0.80. In conclusion, balloon occlusion of the descending aorta increased coronary and common carotid artery blood flow and the frequency of restoration of spontaneous circulation. It was also noted that epinephrine appears to augment the redistribution of blood flow caused by the aortic occlusion.