Comparative Study On Effect Of Aminoguanidine And N～G-nitro-L-arginine Methyl Ester On The Resuscitation Of Cardiac Arrest In Rabbits

Objective To observe the changes of plasma nitric oxide (NO) levels during cardiopulmonary resuscitation (CPR), compare the effect of Aminoguanidine (AG) and N~G-nitro-L-arginine methyl ester(L-NAME) on CPR, explore the underlying mechanism of constitutive nitric oxide synthase and inducible nitric oxide synthase during CPR.Methods Prospective, randomized animal study. Cardiac arrest was electrically induced and left untreated for 5 mins. After lmin of chest compression 40 domestic rabbits were divided into 4 groups(n=10) to receive either 20mg/kg AG, 25mg/kg L-NAME, 20μg/kg epinephrine or 2 ml saline placebo before defibrillation. Successfully resuscitated rabbits were observed for 4hrs. Haemodynamics variables and cardiac functions were monitoring with instrumentation. Arterial blood NO were examined at baseline, the end of 1 minute of chest compression and 15, 30, 60, 120mins after survived.Results Arterial blood NO increased significantly after cardiac arrest in all groups and further increased after survived in epinephrine and saline control groups while declined to baseline in AG and L-NAME groups. During chest compression, the averaged coronary perfusion pressure in AG (40±10mmHg) was higher than in L-NAME groups (34±8mmHg, p=0.001) and both higher compared with control group (20±5mmHg, both p=0.000); LV +dp/dtmax,-dp/dtmax in AG and +dp/dtmax in L-NAME were higher than in control group and +dp/dtmax, -dp/dtmax in AG were higher than in L-NAME group. After survived, LV +dp/dtmax, -dp/dtmax in AG and L-NAME groups were higher than in epinephrine and control groups while AG group (4783±912, 4409±827mm Hg/sec) were higher than L-NAME group (3554±847, 3398±764 mmHg/sec, p=0.001, 0.023 respectively). 4 hrs after resuscitated 8/10 in AG, 7/10 in L-NAME, 6/10 in epinephrine and 4/10 in control group survived (p=0.292).Conclusion Although both AG and L-NAME can increase coronary perfusion pressure, improve left ventricular systolic and diastolic function during CPR and prevent postresuscitation myocardial dysfunction, AG is superior significantly to L-NAME.