title: The Effect of Head Up Cardiopulmonary Resuscitation on Cerebral and Systemic Hemodynamics.
abstract: OBJECTIVE
  Chest compressions during cardiopulmonary resuscitation (CPR) increase arterial and venous pressures, delivering simultaneous bidirectional high-pressure compression waves to the brain. We hypothesized that this may be detrimental and could be partially overcome by elevation of the head during CPR.
  
  
  METHODS
  Female Yorkshire farm pigs (n=30) were sedated, intubated, anesthetized, and placed on a table able to elevate the head 30° (15cm) (HUP) and the heart 10° (4cm) or remain in the supine (SUP) flat position during CPR. After 8minutes of untreated ventricular fibrillation and 2minutes of SUP CPR, pigs were randomized to HUP or SUP CPR for 20 more minutes. In Group A, pigs were randomized after 2minutes of flat automated conventional (C) CPR to HUP (n=7) or SUP (n=7) C-CPR. In Group B, pigs were randomized after 2minutes of automated active compression decompression (ACD) CPR plus an impedance threshold device (ITD) SUP CPR to either HUP (n=8) or SUP (n=8).
  
  
  RESULTS
  The primary outcome of the study was difference in CerPP (mmHg) between the HUP and SUP positions within groups. After 22minutes of CPR, CerPP was 6±3mmHg in the HUP versus -5±3 in the SUP (p=0.016) in Group A, and 51±8 versus 20±5 (p=0.006) in Group B. Coronary perfusion pressures after 22minutes were HUP 6±2 vs SUP 3±2 (p=0.283) in Group A and HUP 32±5 vs SUP 19±5, (p=0.074) in Group B. In Group B, 6/8 pigs were resuscitated in both positions. No pigs were resuscitated in Group A.
  
  
  CONCLUSIONS
  The HUP position in both C-CPR and ACD+ITD CPR significantly improved CerPP. This simple maneuver has the potential to improve neurological outcomes after cardiac arrest.
authors.affiliation: School of Medicine, Chonnam National University, Department of Emergency Medicine, Chonnam National University Hospital. Electronic address: oriryu@naver.com.
authors.forename: Hyun Ho
authors.initials: HH
authors.lastname: Ryu
authors.affiliation: Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, MN. Electronic address: Johanna.moore@hcmed.org.
authors.forename: Johanna C
authors.initials: JC
authors.lastname: Moore
authors.affiliation: Cardiovascular Division, Department of Medicine, University of Minnesota Medical School. Electronic address: yanno001@umn.edu.
authors.forename: Demetris
authors.initials: D
authors.lastname: Yannopoulos
authors.affiliation: Minneapolis Medical Research Foundation, Minneapolis, MN. Electronic address: mlick@mmrf.org.
authors.forename: Michael
authors.initials: M
authors.lastname: Lick
authors.affiliation: Cardiovascular Division, Department of Medicine, University of Minnesota Medical School. Electronic address: Scott047@umn.edu.
authors.forename: Scott
authors.initials: S
authors.lastname: McKnite
authors.affiliation: Department of Emergency Medicine, Seoul National University College of Medicine. Electronic address: shinsangdo@medimail.co.kr.
authors.forename: Sang Do
authors.initials: SD
authors.lastname: Shin
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital. Electronic address: emkty@snubh.org.
authors.forename: Tae Yun
authors.initials: TY
authors.lastname: Kim
authors.affiliation: Zoll Medical Corporation, Minneapolis. Electronic address: ametzger@zoll.com.
authors.forename: Anja
authors.initials: A
authors.lastname: Metzger
authors.affiliation: Cardiovascular Division, Department of Medicine, University of Minnesota Medical School. Electronic address: jrees@umn.edu.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rees
authors.affiliation: Cardiovascular Division, Department of Medicine, University of Minnesota Medical School. Electronic address: atsangar@umn.edu.
authors.forename: Adamantios
authors.initials: A
authors.lastname: Tsangaris
authors.affiliation: 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, Hennepin County Medical Center, Minneapolis, MN. Electronic address: keithlurie@icloud.com.
authors.forename: Keith G
authors.initials: KG
authors.lastname: Lurie
mesh_terms: D000818:Animals; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D006257:Head; D006323:Heart Arrest / Q000503:physiopathology* / Q000628:therapy; D006439:Hemodynamics / Q000502:physiology*; D011187:Posture; D013552:Swine
keywords: Active compression decompression CPR; Cardiac Arrest; Cardiopulmonary resuscitation; Cerebral perfusion; Impedance threshold device; Mechanical CPR