Effect of heparin on mesenteric microcirculation in a rabbit model of cardiac arrest and cardiopulmonary resuscitation

Abstract

Objective To investigate the effect of heparin on mesenteric microcirculation in a rabbit model of cardiac arrest and cardiopulmonary resuscitation (CPR). Methods Thirty-two New Zealand white rabbits of both sexes, weighing 2.0-2.5 kg, were randomly divided into 3 groups using a random number table: control group (group C, n=8), cardiac arrest and CPR group (group CA/R, n=12), and heparin group (group H, n=12). Cardiac arrest was induced by clamping the tracheal tube, and 5 min later CPR was started.Heparin 0.5 mg/kg was injected intravenously at the onset of CPR in group H. The mean arterial pressure (MAP) and heart rate (HR) were recorded before cardiac arrest (T0), immediately after recovery of spontaneous circulation(T1), and at 30 min and 1 h of recovery of spontanenous circulation (T2, 3). A microvessel 15-20 μm in diameter was obtained from the mesentery to record the blood flow velocity, and the K value of microthrombus was calculated. Results Compared with group C, MAP at T1 and HR at T1, 2 were significantly decreased, and the microvascular blood flow velocity was decreased in CA/R and H groups (P<0.05). Compared with group CA/R, no significant change was found in MAP and HR, the microvascular blood flow velocity was significantly increased, and the K value of microthrombus was decreased in group H (P<0.05). Conclusion Heparin can accelerate microvascular blood flow velocity in the mesentery, reduce formation of microthrombus, and improve mesenteric microcirculation in a rabbit model of cardiac arrest and CPR. Key words: Heparin; Microcirculation; Heart arrest; Cardiopulmonary resuscitation