Sodium nitroprusside-enhanced cardiopulmonary resuscitation improves resuscitation rates after prolonged untreated cardiac arrest in two porcine models*

Abstract

Objective Sodium nitroprusside-enhanced CPR (SNPeCPR) consists of active compression decompression (ACD), impedance threshold device (ITD), abdominal binding (AB), and large intravenous doses of sodium nitroprusside (SNP). We hypothesize SNPeCPR will significantly increase carotid blood flow and return of spontaneous circulation compared to standard CPR after prolonged ventricular fibrillation (VF) and pulseless electrical activity (PEA) cardiac arrest. Design Prospective randomized animal study. Setting Hennepin County Medical Center Animal Laboratory. Subjects 40 Yorkshire female farm-bred pigs weighing 32 ± 2kg. Interventions In protocol A, 24 isoflurane anesthetized pigs underwent 15 minutes of untreated VF and were subsequently randomized to receive S-CPR (n=6), ACD CPR +ITD (n=6), or SNPeCPR (n=12) for up to 15 minutes. First defibrillation was attempted at minute 6 of CPR. In protocol B, a separate group of 16 pigs underwent 10 minutes of untreated VF followed by 3 minutes of chest compression only CPR followed by counter-shock induced PEA after which animals were randomized to S-CPR (n=8) or SNPeCPR (n=8). Measurements and Main Results The primary endpoint was carotid blood flow during CPR and return of spontaneous circulation (ROSC). Secondary endpoints included end-tidal CO2 (ETCO2) as well as coronary (CPP) and cerebral perfusion pressure (CerPP). After prolonged untreated VF, SNPeCPR demonstrated superior rates of ROSC when compared to S-CPR and ACD CPR+ITD (12/12, 0/6, 0/6 respectively, p<0.01). In animals with PEA, SNPeCPR increased ROSC rates when compared to S-CPR. In both groups, carotid blood flow, CPP, CerPP, and ETCO2 were increased with SNPeCPR. Conclusions In pigs, SNPeCPR significantly increased ROSC rates as well as carotid blood flow and ETCO2, when compared to S-CPR or ACD CPR+ITD.

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

“…This approach was meant to maximize resuscitation rates in the S-CPR group because when epinephrine was given only at min 5 of CPR, ROSC rates in our laboratory were poor and we would be unable to compare neurological function between groups. 11 In contrast to ROSC rates, there were significant differences in 24-h survival rates. We speculate that SNPeCPR provides neuroprotection, but the protective mechanisms other than the increase in circulation remain unknown.…”

“…10 Furthermore, SNPeCPR has been shown to improve ROSC rates after prolonged VF and pulseless electrical activity (PEA) arrest compared to treatment with S-CPR and American Heart Association resuscitation recommendations. 11 …”

Controlled pauses at the initiation of sodium nitroprusside-enhanced cardiopulmonary resuscitation facilitate neurological and cardiac recovery after 15 mins of untreated ventricular fibrillation

“…Sodium nitroprusside “enhanced”-cardiopulmonary resuscitation, or SNPeCPR, is a method of resuscitation that consists of: 1) active compression-decompression CPR with an impedance threshold device (ACD-CPR + ITD) which improves vital organ blood flow, and improves short and long term survival compared to standard CPR in both animal and human studies (7–9), 2) manual lower abdominal binding which mechanically increases resistance to descending aortic blood flow, augments venous blood return to the heart, thereby effectively redistributing blood flow (10, 11) and, 3) high dose intravenous boluses of sodium nitroprusside which vasodilates coronary and cerebral vascular beds and decreases peripheral vascular resistance to the heart and brain (12, 13). …”

“…Furthermore, SNPeCPR use has resulted in a >90% ROSC rate after 15 minutes of untreated ventricular fibrillation and pulseless electrical activity (PEA) arrest (13). SNPeCPR significantly improved outcomes in the same animal model when compared to the 2010 American Heart Association resuscitation recommendations (standard CPR) ACLS protocol (13). …”

New Application of a Traditional Vasoactive Agent, Sodium Nitroprusside, in Targeted Temperature Management During Cardiac Arrest and Resuscitation*

“…Recently, the combination of SNP with mechanical CPR (SNPeCPR) has been proven to optimize hemodynamics during CPR and improve myocardial and neurologic function and therefore the survival outcome in animal studies (12,13). Based on the publication, in this issue of Critical Care Medicine, Debaty et al (14) investigated the effect of SNPeCPR on heat exchange during surface cooling in a prolonged ventricular fibrillation (VF) porcine model.…”