Abstract 300: No Improved Outcome with Vasopressor Drugs or Sodium Nitroprusside in a 10-Minute Untreated VF Cardiac Arrest Model in Swine
Background: The use of epinephrine to treat cardiac arrest is increasingly challenged. However, previous investigations have shown minimal favorable outcome without the use of vasopressors or surprisingly positive outcome using sodium-nitroprusside in a modified resuscitation protocol.
Hypothesis: Vasopressor support improves coronary perfusion pressure (CPP) and favorable 24h neurological outcome in prolonged cardiac arrest.
Methods: 35 domestic swine (33.5±5.5 kg) had VF electrically induced and left untreated for 10 minutes. Chest compression only (100/min) advanced life support was given for the first 3 of 7 epochs (2 min each) before ventilation with oxygen was started. Defibrillation attempts were made every 2 minutes. Animals were randomly assigned to one of 5 treatment groups: Placebo, epinephrine (0.045mg/kg), norepinephrine (0.025mg/kg), sodium-nitroprusside (0.0165 mg/kg) plus epinephrine (0.045mg/kg) or sodium-nitroprusside (0.0165 mg/kg). If the rhythm analysis at the beginning of epoch 3 to 7 did not show a perfusing rhythm, the assigned study drug was administered and the protocol continued until ROSC or 25 min, after which the animal was considered non-resuscitated. A swine cerebral performance category (CPC) was determined at 24 hours after onset of cardiac arrest. Data are presented as median and quartiles.
Results: ROSC was achieved in 22 (63%) animals and 12 (34%) survived for 24 hours with a favorable neurological outcome (CPC 1+2) in 10 (29%). There was no significant difference in between drug groups. Of these 10, seven achieved ROSC within the first two epochs before any study drug was administered. In the remaining three a vasopressor drug was administered. CPP (mmHg) was significantly higher in animals with favorable outcome during the first two epochs (Epoch 1: 29 (20/40) vs. 15 (10/19); Epoch 2: 18 (12/25) vs. 7 (3/13); p < 0.05).
Conclusion: Following four minutes of chest compressions and two defibrillation attempts, the administration of epinephrine, norepinephrine, sodium-nitroprusside plus epinephrine or sodium-nitroprusside alone did not influence 24-hour neurological outcome in a swine model of out-of-hospital VF cardiac arrest.
- © 2012 by American Heart Association, Inc.