title: Mild therapeutic hypothermia is superior to controlled normothermia for the maintenance of blood pressure and cerebral oxygenation, prevention of organ damage and suppression of oxidative stress after cardiac arrest in a porcine model.
abstract: BACKGROUND
  Mild therapeutic hypothermia (HT) has been implemented in the management of post cardiac arrest (CA) syndrome after the publication of clinical trials comparing HT with common practice (ie, usually hyperthermia). Current evidence on the comparison between therapeutic HT and controlled normothermia (NT) in CA survivors, however, remains insufficient.
  
  
  METHODS
  Eight female swine (sus scrofa domestica; body weight 45 kg) were randomly assigned to receive either mild therapeutic HT or controlled NT, with four animals per group. Veno-arterial extracorporeal membrane oxygenation (ECMO) was established and at minimal ECMO flow (0.5 L/min) ventricular fibrillation was induced by rapid ventricular pacing. After 20 min of CA, circulation was restored by increasing the ECMO flow to 4.5 L/min; 90 min of reperfusion followed. Target core temperatures (HT: 33°C; NT: 36.8°C) were maintained using the heat exchanger on the oxygenator. Invasive blood pressure was measured in the aortic arch, and cerebral oxygenation was assessed using near-infrared spectroscopy. After 60 min of reperfusion, up to three defibrillation attempts were performed. After 90 min of reperfusion, blood samples were drawn for the measurement of troponin I (TnI), myoglobin (MGB), creatine-phosphokinase (CPK), alanin-aminotransferase (ALT), neuron-specific enolase (NSE) and cystatin C (CysC) levels. Reactive oxygen metabolite (ROM) levels and biological antioxidant potential (BAP) were also measured.
  
  
  RESULTS
  Significantly higher blood pressure and cerebral oxygenation values were observed in the HT group (P<0.05). Sinus rhythm was restored in all of the HT animals and in one from the NT group. The levels of TnI, MGB, CPK, ALT, and ROM were significantly lower in the HT group (P<0.05); levels of NSE, CysC, and BAP were comparable in both groups.
  
  
  CONCLUSIONS
  Our results from animal model of cardiac arrest indicate that HT may be superior to NT for the maintenance of blood pressure, cerebral oxygenation, organ protection and oxidative stress suppression following CA.
authors.affiliation: Cardiovascular Center, Na Homolce Hospital, Prague 15030, Czech Republic. ostadal.petr@gmail.com
authors.forename: Petr
authors.initials: P
authors.lastname: Ostadal
authors.forename: Mikulas
authors.initials: M
authors.lastname: Mlcek
authors.forename: Andreas
authors.initials: A
authors.lastname: Kruger
authors.forename: Svatava
authors.initials: S
authors.lastname: Horakova
authors.forename: Marcela
authors.initials: M
authors.lastname: Skabradova
authors.forename: Frantisek
authors.initials: F
authors.lastname: Holy
authors.forename: Tomas
authors.initials: T
authors.lastname: Svoboda
authors.forename: Jan
authors.initials: J
authors.lastname: Belohlavek
authors.forename: Vladimir
authors.initials: V
authors.lastname: Hrachovina
authors.forename: Ludek
authors.initials: L
authors.lastname: Taborsky
authors.forename: Vlasta
authors.initials: V
authors.lastname: Dudkova
authors.forename: Hana
authors.initials: H
authors.lastname: Psotova
authors.forename: Otomar
authors.initials: O
authors.lastname: Kittnar
authors.forename: Petr
authors.initials: P
authors.lastname: Neuzil
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D001831:Body Temperature; D001921:Brain / Q000378:metabolism*; D004195:Disease Models, Animal; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods; D005260:Female; D006323:Heart Arrest / Q000378:metabolism*; D007036:Hypothermia, Induced / Q000379:methods*; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism*; D034421:Sus scrofa
chemical_list: D015415:Biomarkers; D010100:Oxygen