Background The effect of rescue breathing on neurologic prognosis after cardiopulmonary resuscitation (CPR) is controversial.Therefore, we investigated the cerebral microcirculatory and oxygen metabolism during continuous compression (CC) and 30∶ 2 CPR (VC) in a porcine model of cardiac arrest to determine which is better for neurologic prognosis after CPR.Methods After 4 min of ventrieular fibrillation, 20 pigs were randomised into two groups (n=10/group) receiving CC-CPR or VC-CPR.Cerebral oxygen metabolism and blood flow were measured continuously using laser Doppler flowmetry.Haemodynamic data were recorded at baseline and 5 min, 30 min, 2 h and 4 h after restoration of spontaneous circulation (ROSC).Results Compared with the VC group, the mean cortical cerebral blood flow was significantly higher at 5 min ROSC in the CC group (P< 0.05), but the difference disappeared after that time point.Brain percutaneous oxygen partial pressures were higher, and brain percutaneous carbon dioxide partial pressures were lower, in the VC group from 30 min to 4 h after ROSC; significant differences were found between the two groups (P<0.05).However, no significant difference of the cerebral oxygen extraction fraction existed between the two groups.Conclusions Inconsistency of systemic circulation and cerebral microcirculation with regard to blood perfusion and oxygen metabolism is common after CPR.No significant differences in cortical blood flow and oxygen metabolism were found between the CC-CPR and VC-CPR groups after ROSC.