[Animal modeling] - Comparison of two methods for preparing rabbit models of cardiac arrest

  Objective: To compare the characteristics of physiological indexes of two rabbit models of cardiac arrest induced by potassium chloride and transesophageal chest wall electric fibrillation during cardiopulmonary resuscitation

  Methods: New Zealand white rabbits were divided into two groups according to the method of random number table: potassium chloride induced cardiac arrest group (10% potassium chloride 0.3 mL/kg pulse intravenous injection induced cardiac arrest) and electric fibrillation group (35 mA AC was used to induce cardiac arrest via esophagus chest wall), 10 rats in each group. Cardiopulmonary resuscitation was performed 5 minutes after cardiac arrest. The time of induced cardiac arrest, cardiopulmonary resuscitation, restoration of spontaneous circulation (ROSC), arterial blood gas and blood lactic acid (Lac) levels 1 hour after recovery of spontaneous circulation, and survival 72 hours after recovery were compared between the two groups

  Results: All 20 animals successfully induced cardiac arrest. Compared with the electric fibrillation group, the time of induced cardiac arrest [(9.90 ± 2.47) s compared with (27.40 ± 6.48) s] and the time of cardiopulmonary resuscitation [(61.61 ± 26.51) s compared with (132.00 ± 18.55) s] in the potassium chloride induced fibrillation group were significantly shortened (P<0.01). Nine animals in the potassium chloride induced fibrillation group and the electric fibrillation group recovered their spontaneous circulation, and 8 and 5 animals survived 72 hours respectively. Compared with the electric fibrillation group, The arterial blood gas pH [(7.38 ± 0.06) vs (7.29 ± 0.11)] and HCO3 concentration [(21.86 ± 3.65) mmol/L vs (18.32 ± 2.61) mmol/L] in the potassium chloride induced fibrillation group were significantly higher (P<0.05) 1 hour after the recovery of autonomic circulation, and the Lac level [(1.77 ± 0.77) mmol/L vs (5.39 ± 3.40) mmol/L] was significantly lower (P<0.01), while the differences in the partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), and K+concentration were not statistically significant. Conclusion Compared with the transesophageal thoracic wall AC stimulation, Method comparison, Pulse injection of potassium chloride can more easily induce sudden cardiac arrest in rabbits, and the internal environment is more stable and the survival rate is higher after resuscitation