title: Tilting for perfusion: head-up position during cardiopulmonary resuscitation improves brain flow in a porcine model of cardiac arrest.
abstract: BACKGROUND
  Cerebral 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).
  
  
  METHODS
  Twenty-two pigs were sedated, intubated, anesthetized, paralyzed and placed on a tilt table. After 6min of untreated ventricular fibrillation (VF) CPR was performed on 14 pigs for 3min with an automated CPR device called LUCAS (L) plus an impedance threshold device (ITD), followed by 5min of L-CPR+ITD at 0° supine, 5min at 30° HUT, and then 5min 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.
  
  
  RESULTS
  Coronary perfusion pressure was 19±2mmHg 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±0.04mlmin(-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.
  
  
  CONCLUSIONS
  During CPR, HDT decreased brain flow whereas HUT significantly lowered ICP and improved cerebral perfusion. Further studies are warranted to explore this new resuscitation concept.
authors.affiliation: Department of Medicine-Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA; UJF-Grenoble 1/CNRS/CHU de Grenoble/TIMC-IMAG UMR 5525, Grenoble, France. Electronic address: gdebaty@gmail.com.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Debaty
authors.affiliation: Department of Emergency Medicine, Seoul National Hospital, Seoul, Republic of Korea.
authors.forename: Sang Do
authors.initials: SD
authors.lastname: Shin
authors.affiliation: Department of Emergency Medicine, Hennepin County Medical Center, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Anja
authors.initials: A
authors.lastname: Metzger
authors.affiliation: Department of Emergency Medicine, Seoul National Hospital, Seoul, Republic of Korea.
authors.forename: Taeyun
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, Chonnam National University Hospital, Republic of Korea.
authors.forename: Hyun Ho
authors.initials: HH
authors.lastname: Ryu
authors.affiliation: Department of Medicine-Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rees
authors.affiliation: Department of Emergency Medicine, Hennepin County Medical Center, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: McKnite
authors.affiliation: Department of Integrated Biology & Physiology, Medical School, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Matsuura
authors.affiliation: Department of Emergency Medicine, Hennepin County Medical Center, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Lick
authors.affiliation: Department of Medicine-Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Demetris
authors.initials: D
authors.lastname: Yannopoulos
authors.affiliation: Department of Emergency Medicine, Hennepin County Medical Center, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Keith
authors.initials: K
authors.lastname: Lurie
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006112:Gravitation; D006323:Heart Arrest / Q000209:etiology / Q000628:therapy; D006801:Humans; D056888:Patient Positioning / Q000009:adverse effects / Q000379:methods; D012039:Regional Blood Flow; D013552:Swine; D014693:Ventricular Fibrillation / Q000150:complications
keywords: Cardiac arrest; Cardiopulmonary resuscitation; Cerebral perfusion; Impedance threshold device; Mechanical CPR