Tilting for perfusion: Head-up position during cardiopulmonary resuscitation improves brain flow in a porcine model of cardiac arrest

IntroductionCerebral perfusion is compromised during cardiopulmonary resuscitation (CPR). We hypothesized that beneficial effects of gravity on the venous circulation during CPR performed in the head-up tilt (HUT) position would improve cerebral perfusion compared with supine or head-down tilt (HDT).MethodsTwenty-two pigs were sedated, intubated, anesthetized, paralyzed and placed on a tilt table. After 6 min of untreated ventricular fibrillation (VF) CPR was performed on 14 pigs for 3 min with an automated CPR device called LUCAS (L) plus an impedance threshold device (ITD), followed by 5 min of L-CPR + ITD at 0° supine, 5 min at 30° HUT, and then 5 min at 30° HDT. Microspheres were used to measure organ blood flow in 8 pigs. L-CPR + ITD was performed on 8 additional pigs at 0°, 20°, 30°, 40°, and 50° HUT.ResultsCoronary perfusion pressure was 19 ± 2 mmHg at 0° vs. 30 ± 3 at 30° HUT (p < 0.001) and 10 ± 3 at 30° HDT (p < 0.001). Cerebral perfusion pressure was 19 ± 3 at 0° vs. 35 ± 3 at 30° HUT (p < 0.001) and 4 ± 4 at 30° HDT (p < 0.001). Brain–blood flow was 0.19 ± 0.04 ml min⁻¹ g⁻¹ at 0° vs. 0.27 ± 0.04 at 30° HUT (p = 0.01) and 0.14 ± 0.06 at 30° HDT (p = 0.16). Heart blood flow was not significantly different between interventions. With 0, 10, 20, 30, 40 and 50° HUT, ICP values were 21 ± 2, 16 ± 2, 10 ± 2, 5 ± 2, 0 ± 2, −5 ± 2 respectively, (p < 0.001), CerPP increased linearly (p = 0.001), and CPP remained constant.ConclusionDuring CPR, HDT decreased brain flow whereas HUT significantly lowered ICP and improved cerebral perfusion. Further studies are warranted to explore this new resuscitation concept.