Sodium nitroprusside enhanced cardiopulmonary resuscitation prevents post-resuscitation left ventricular dysfunction and improves 24-hour survival and neurological function in a porcine model of prolonged untreated ventricular fibrillation

Abstract

Aim of study: Sodium nitroprusside-enhanced CPR, or SNPeCPR, consists of active compression-decompression CPR with an impedance threshold device, abdominal compression, and intravenous sodium nitroprusside (SNP). We hypothesize that SNPeCPR will improve post resuscitation left ventricular function and neurological function compared to standard (S) CPR after 15 min of untreated ventricular fibrillation in a porcine model of cardiac arrest.

Methods: Pigs (n = 22) anesthetized with isoflurane underwent 15 min of untreated ventricular fibrillation, were then randomized to 6 min of S-CPR (n = 11) or SNPeCPR (n = 11) followed by defibrillation. The primary endpoints were neurologic function as measured by cerebral performance category (CPC) score and left ventricular ejection fraction.

Results: SNPeCPR increased 24-hour survival rates compared to S-CPR (10/11 versus 5/11, p = 0.03) and improved neurological function (CPC score 2.5 ± 1, versus 3.8 ± 0.4, respectively, p = 0.004). Left ventricular ejection fractions at 1, 4 and 24 hours after defibrillation were 72 ± 11, 57 ± 11.4 and 64 ± 11 with SNPeCPR versus 29 ± 10, 30 ± 17 and 39 ± 6 with S-CPR, respectively (p < 0.01 for all).

Conclusions: In this pig model, after 15 min of untreated ventricular fibrillation, SNPeCPR significantly improved 24-hour survival rates, neurologic function and prevented post-resuscitation left ventricular dysfunction compared to S-CPR.

Conflict of interest statement

Conflict of interest

Demetris Yannopoulos, MD, is the Medical Director of the Minnesota Resuscitation Consortium, a state wide initiative to improve survival in the state of MN from cardiac arrest. This initiative is sponsored by the Medtronic Foundation and is part of the HeartRescue Program. There are no conflicts related to this investigation.

Tom P. Aufderheide, MD, has board membership for Take Heart America and Citizen CPR Foundation, has consulted for JoLife Medical and Medtronic Foundation, and has received grants/ grants pending from the NHLBI Immediate Trial, NHLBI Resuscitation Outcomes Consortium, NINDS Neurological Emergency Treatment Trials Network, and NHLBI Medical College of Wisconsin K12 Research Career Development.

Keith Lurie, MD, is the inventor of ACD+ITD CPR used in this study and has formed a company that promotes its sales (ACSI).

The remaining authors have no conflict of interest to report.

Copyright © 2011 Elsevier B.V. All rights reserved.

Figures

Figure 1

Schematic of experimental protocol. SNPeCPR: sodium nitroprusside-enhanced CPR; S-CPR: standard CPR; VF: ventricular fibrillation; ROSC: return of spontaneous circulation; SNP: Sodium Nitroprusside; Epi: Epinephrine.

Figure 2

24-hours neurological assessment. SNPeCPR significantly improved neurological function compared to S-CPR. Good neurological function (CPC of 1 & 2) was only present in the SNPeCPR group. CPC: cerebral performance category score (1 = normal, 4 = coma); SNPeCPR: sodium nitroprusside-enhanced CPR; S-CPR: standard CPR. * Means statistical significance with a p < 0.05.

Figure 3

Left Ventricular Function after return of spontaneous circulation. SNPeCPR alleviated post resuscitation left ventricular dysfunction. Left ventricular ejection fraction (LVEF) was normal over the 24 h of observation in the SNPeCPR and severely depressed in the S-CPR. LVEF was calculated using Simpson’s method of volumetric analysis. * means statistically significant difference with p < 0.05 compared to S-CPR.