Sodium nitroprusside enhanced cardiopulmonary resuscitation improves survival with good neurological function in a porcine model of prolonged cardiac arrest.

OBJECTIVE: To assess the effectiveness of sodium nitroprusside (SNP)-"enhanced" cardiopulmonary resuscitation (SNPeCPR) on 24-hr survival rates compared to standard CPR in animals after cardiac arrest. SNPeCPR consists of large intravenous SNP bolus doses during CPR enhanced by active compression-decompression CPR, an inspiratory impedance threshold device (ITD), and abdominal binding (AB). The combination of active compression-decompression CPR+ITD+AB without SNP will be called "enhanced" or eCPR.

DESIGN: Randomized, blinded, animal study.

SETTING: Preclinical animal laboratory.

SUBJECTS: Twenty-four female farm pigs (30 ± 1 kg).

INTERVENTIONS: Isoflurane anesthetized and intubated pigs were randomized after 8 mins of untreated ventricular fibrillation to receive either standard CPR (n = 8), SNPeCPR (n = 8), or eCPR (n = 8) for 25 mins followed by defibrillation.

MEASUREMENTS AND MAIN RESULTS: The primary end point was carotid blood flow during CPR and 24-hr survival with good neurologic function defined as an overall performance category score of ≤2 (1 = normal, 5 = brain dead or dead). Secondary end points included hemodynamics and end-tidal CO2. SNPeCPR significantly improved carotid blood flow and 24-hr survival rates with good neurologic function compared to standard CPR or eCPR (six of eight vs. zero of eight vs. one of eight, p < .05). The improved survival rates were associated with higher coronary perfusion pressure and ETco2 during CPR.

CONCLUSION: In pigs, SNPeCPR significantly improved hemodynamics, resuscitation rates, and 24-hr survival rates with good neurologic function after cardiac arrest when compared with standard CPR or eCPR alone.