Abstract 72: Effects of Epinephrine and Sodium Nitroprusside on Left Ventricular Wall Thickness and Cavity Size and Carotid Blood Flow During Cardiopulmonary Resuscitation.
Introduction: Pulmonary edema is common during prolonged cardiopulmonary resuscitation (CPR). Epinephrine is commonly used during prolonged CPR. Sodium nitroprusside (SNP) has been shown to cause an increase in LV compliance and improve the diastolic properties of normal and ischemic myocardium in animals and humans. We sought to identify the effects of SNP and epinephrine on the LV wall thickness and cavity size during CPR.
Methods: 6 female pigs, intubated and anesthetized, had untreated VF for 10 min followed by active compression decompression plus inspiratory impedance threshold device plus abdominal binding CPR with intravenous bolus of SNP (2 mg every 3min) for a total of 6 minutes followed by the same method of CPR but with infusion of 0.5 mg of epinephrine every 3 minutes for another 6 minutes followed by 120 J Shocks. Another 6 animals had the same protocol but were treated only with SNP for the 12min of CPR. Coronary perfusion pressure and carotid blood flow were recorded continuously. An intracardiac echocardiogram (ICE) recorded the short axis of the left ventricular (LV) mid cavity. LV free and septal wall thickness and cavity diameter were measured during decompression. Paired t-test was used for statistical analysis.
Results: Epinephrine infusion significantly increased coronary perfusion pressure compared to SNP (58±12 vs 32±5, p<0,05), drastically decreased mean carotid blood flow (42±15 vs 109±22, p<0.05). Epinephrine increased LV free and septal wall thickness compared to SNP (1.3±0.2 and 1.35±0.3 vs 0.7 ±0.1 and 0.8±0.1 cm p<0.05) and decreased LV cavity size (2.2±0.7 vs 3.6±1.05 cm p<0,01). 5/6 animals developed visible pulmonary edema after the second dose of epinephrine. 6/6 animals had return of spontaneous circulation. All animals treated only with SNP had ROSC, did not develop pulmonary edema and there were no changes in the ICE parameters over time.
Conclusions: Epinephrine during CPR caused significant increase in LV wall thickness and coronary perfusion pressure and a decrease in LV cavity size and carotid blood flow compared to SNP. Those effects of epinephrine could also explain the frequent development of pulmonary edema during CPR.
- © 2010 by American Heart Association, Inc.