title: Vasopressors are essential during cardiopulmonary resuscitation in rats: Is vasopressin superior to adrenaline?
abstract: BACKGROUND
  Vasopressors are recommended for cardiopulmonary resuscitation (CPR) after cardiac arrest. In order to assess possible benefits regarding neurological recovery, vasopressin versus adrenaline and the combination of both was tested against placebo in a cardiac arrest model in rats.
  
  
  METHODS
  Under anaesthesia with halothane and N2O, cardiac arrest was initiated via transoesophageal electrical fibrillation. After 7 min of global ischaemia, CPR was performed by external chest compression combined with defibrillation. Animals were randomly assigned to three groups receiving adrenaline, vasopressin and a combination of both (n = 15 per group) versus placebo (n = 8). At 1, 3 and 7 days animals were tested according to a neurological deficit score (NDS). After 7 days of reperfusion, coronal brain sections were analysed by Nissl- and TUNEL-staining. Viable as well as TUNEL-positive neurons were counted in the hippocampal CA-1 sector. For statistical analysis, the log rank and the Kruskal-Wallis ANOVA test were used. All data are given as mean+/-S.D.; a p-value <0.05 was considered significant.
  
  
  RESULTS
  Mean arterial blood pressure (MAP) measured in the aorta did not differ between the vasopressor groups, whereas placebo animals had significantly lower levels. Survival to 7 days revealed significant differences between the placebo (n = 0/8) and all vasopressor groups (adrenaline, 10/15; adrenaline/vasopressin, 8/15; vasopressin, 12/15). Histological deficit scoring by quantitative analysis of the Nissl- and TUNEL-staining showed no difference in the amount of viable and apoptotic neurons in the vasopressin group (viable: 33+/-18; apoptotic: 63+/-23) versus the adrenaline group (viable: 21+/-12; apoptotic: 67+/-17) and the adrenaline/vasopressin group (viable: 31+/-26; apoptotic: 61+/-27). Neurological deficit scoring did not show any differences between the vasopressor groups.
  
  
  CONCLUSIONS
  Administration of arginine-vasopressin during CPR does not improve behavioural and cerebral histopathological outcome, compared to the use of adrenaline or the combination of both vasopressors, after cardiac arrest in rats.
authors.affiliation: Department of Anaesthesiology, University of Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg, Germany. Erik.Popp@med.uni-heidelberg.de
authors.forename: Erik
authors.initials: E
authors.lastname: Popp
authors.forename: Peter
authors.initials: P
authors.lastname: Vogel
authors.forename: Peter
authors.initials: P
authors.lastname: Teschendorf
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Böttiger
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000473:pathology; D016887:Cardiopulmonary Resuscitation; D004359:Drug Therapy, Combination; D004837:Epinephrine / Q000008:administration & dosage / Q000627:therapeutic use*; D006323:Heart Arrest / Q000401:mortality / Q000628:therapy*; D020287:In Situ Nick-End Labeling; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012183:Retrograde Degeneration; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D014667:Vasopressins / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D014662:Vasoconstrictor Agents; D014667:Vasopressins; D004837:Epinephrine