A percutaneous left ventricular assist device has been shown to be able to perfuse cardiac and cerebral tissues during cardiac arrest and may be a useful supplement to current methods in resuscitation. We wished to assess device-assisted circulation during cardiac arrest with microspheres injections and continuous end-tidal CO 2 monitoring, and used cerebral microdialysis to detect ischaemia in the brain.12 anaesthetised pigs had microdialysis and pressure catheters implanted via craniotomy. The percutaneous assist device was deployed transfemorally. Ventricular fibrillation was induced by angioplasty-balloon occlusion of the left coronary artery. Cerebral microdialysis samples representing 0–20 and 20–40min of cardiac arrest with assisted circulation were analysed for markers of cerebral injury (glucose, pyruvate, lactate, and glycerol).Microdialysis showed no ischaemic changes after 20min of cardiac arrest (P=NS to Baseline for glucose, glycerol, lactate, pyruvate and lactate/pyruvate ratio) in subjects with maintained end-tidal CO 2 values above 1.3kPa (10mmHg). After 40min only lactate showed a significant change compared to Baseline (P<0.05). Microspheres flow to the brain was 57% and myocardial flow was 72% compared to Baseline after 15min (P<0.05). After 45min flow declined to 22% and 40% of Baseline, respectively (P=NS vs. 15min).A percutaneous left ventricular assist device may prevent ischaemic cerebral injury during cardiac arrest for a limited time. Cerebral injury and tissue perfusion were indicated by end-tidal CO 2 .