Establishment of mechanical chest compression cardiopulmonary resuscitation model in rats

  OBJECTIVE: To explore a feasible method for replicating a rat cardiopulmonary resuscitation (CPR) model with mechanical chest compressions.

  Method: Adult male SD rats were randomly divided into control group (n=6) and model group (n=10). After intraperitoneal injection of 10% chloral hydrate, tracheal intubation and left femoral artery intubation were performed. Under the conditions of monitoring the electrocardiogram and arterial blood pressure, the model group underwent tracheal obstruction (TO) and cardiac arrest (CA) for 2 minutes, using ventilator-assisted and self-made animal chest compression apparatus to perform CPR.

   Results: Spontaneous respiratory arrest, cyanosis, and arrhythmia occurred quickly after TO in the model group. Cardiac arrest occurred in 4 to 5 minutes, arterial systolic blood pressure dropped below 40 mmHg, pulse pressure disappeared, and CA appeared. After CPR was given 2 minutes later, 8 rats recovered spontaneous circulation (return of spontaneous circulation, ROSC) and developed transient reperfusion arrhythmia. 6 rats regained consciousness and survived for 24 hours. The blood biochemical analysis indicated that the rats in the model group had electrolyte disturbance, acidosis, renal damage, and elevated myocardial enzyme spectrum. Pathological section observation revealed that the rats in the model group had rhabdomyolysis, no glomerular reflow, decreased neurons, and pulmonary congestion and other organ damage.

   Conclusion: Mechanical chest compressions can provide the basic cardiac output required for CPR in CA rats, and can successfully establish a rat CPR model.