Comparison of the effects of aminoguanidine and NG-nitro-L-arginine methyl ester on resuscitation from cardiac arrest in rabbits

Abstract

Objective To observe the changes of nitric oxide (NO) levels in plasma during cardiopul-monary resuscitation (CPR) and to compare the effects of aminoguanidine (AG) and NG-nitro-L-arginine methyl ester (L-NAME) on CPR. Method This was a prospective, randomized animal study performed at the Function Laboratory of Lanzhou University. Cardiac arrest was electrically induced and was left untreated for 5 min. After performing chest compression for 1 min, 40 domestic rabbits were divided into four groups (n = 10) to receive ei-ther 20 mg/kg AG, 25 mg/kg L-NAME, 0.02 mg/kg epinephrine or 2 ml saline placebo before defibrillation. Successfully resuscitated rabbits were observed for a further 4 h. Hernodynamics variables and cardiac functions were monitored with appropriate instrumentation. Arterial blood NO levels were examined at baseline, at the end of 1 min chest compression and at 15, 30, 60 and 120 min after survival. Repeated measures analysis of variance was used to determine statistical significance between groups. Results During chest compression, the mean + stan-dard deviation coronary perfusion pressure was higher in the AG group (40±10 mmHg) than in the L-NAME group (34±8 mmHg; P =0.001) and was higher in both groups with the control group (20±5 mmHg; both P =0.000). Left ventricular + dp/dtmax and- dp/dtmax were higher in the AG group than in the L-NAME group. In the surviving rabbits, the left ventricular + dp/dtmax and - dp/dtmax were higher in the AG and L-NAME groups than in the epinephrine and control groups and were higher in the AG group (4783±912, 4409±827 mmHg/s)than in the b-NAME group (3554±847, 3398±764 mmHg/s; P = 0.001 and 0.023, respectively). Conclu-sions Both AG and L-NAME increased the coronary perfusion pressure, and improved left ventricular systolic and diastolic function during CPR and prevented post-resuscitation myocardial dysfunction. However, AG was signifi-canfly superior to L-NAME. Key words: Cardiac arrest; Cardiopulmonary resuscitation; Nitric oxide; Aminnguanidine; NG; -nitro-L-arginine methyl ester