Abstract 56: Ventilation Is Necessary During Cardiopulmonary Resuscitation In A Rat Model Of Cardiac Arrest Induced By Airway Obstruction
Recent studies have showed that hypoventilation during cardiopulmonary resuscitation (CPR) improved the rates of return of spontaneous circulation (ROSC) and prognosis. However, there are few studies about the ventilation strategies during CPR in cardiac arrest caused by airway obstruction. To compare the effects of the three ventilation strategies during CPR in an animal model of cardiac arrest induced by airway obstruction, we investigated the rates of ROSC, survival rates, plasma cytokine levels, and lactate levels. thirty-six male Sprague Dawley rats were anesthetized with intraperitoneal injection of pentobarbital. Cardiac arrest was induced by airway obstruction. After 3 minutes of cardiac arrest, animals were randomized to receive one of the three ventilation strategies during CPR (n = 12 per group): normoventiraion (28 breaths/min), hypoventilation (14 breaths/min), or no-ventilation. The rates of chest compression (CC) was 240 –260 compressions/min and the depth of CC adjusted to maintain mean arterial pressure more than 25 mmHg in all groups. After 5 minutes of CPR, epinephrine (0.02 mg/kg) was administered, and all rats were ventilated at the rates of 28 breaths/min in FiO2 1.0. The rates of ROSC were 83%, 58%, 0% for the normoventilation, hypoventilation, and no-ventilation groups, respectively. The PaCO2 levels immediately after ROSC were 74mmHg and 88 mmHg for the normoventilation, and hypoventilation groups, respectively. The increases of plasma cytokine (TNF-a, and IL-6) levels and lactate levels after ROSC in the normoventilation group were significantly less than those in the hypoventilation group. The present study showed that normoventilation during CPR improved the rates of ROSC and the survival rates after ROSC in the animal cardiac arrest model induced by airway obstruction. Moreover, normoventilation attenuated the elevation of cytokine and lactate responses. These findings suggest that ventilation may be necessary during CPR in cardiac arrest caused by airway obstruction.