Prehospital bicarbonate use in cardiac arrest: A 3-year experience

Abstract

The American Heart Association no longer recommends the routine use of sodium bicarbonate in cardiac arrests. Reasons cited include the lack of documented effect on clinical outcome and potential adverse effects of metabolic alkalosis and hypernatremia. We reviewed 36 months of experience with 619 nontrauma adult, prehospital cardiac arrest patients to identify 273 successful resuscitations who had emergency department blood gases and electrolytes performed. Determination of complications associated with prehospital intravenous sodium bicarbonate and its impact on survival in resuscitated patients was undertaken. Fifty-eight patients did not receive sodium bicarbonate (NO HCO 3 group) and had short cardiopulmonary resuscitation (CPR) times (7.4 ± 5.5 minutes). Two hundred fifteen patients did receive sodium bicarbonate (HCO 3 group) and had significantly longer CPR times (23.3 ± 13.5 minutes, P ≤ .001). Both groups demonstrated routine early chest compression and hyperventilation as evidenced by no significant difference in paramedic response time or rate of intubations. Initial emergency department blood gas results of both groups were not significantly different. No patients in the NO HCO 3 group had hypernatremia (sodium [Na] + > 150), whereas four patients (2%) in the HCO 3 group were hypernatremic. Eight patients (14%) in the NO HCO 3 group and 37 patients (17%) in the HCO 3 group were alkalotic with pH values greater than 7.49 ( P = NS). Six patients (10%) of the NO HCO 3 group and 24 patients (11%) of the HCO 3 group had a metabolic component to the alkalosis as defined by a positive base excess value ( P = NS). Survival was examined in both groups following standardization for the presenting rhythm of ventricular fibrillation and CPR time intervals of 5 minutes. Survival did not differ significantly between the NO HCO 3 group and the HCO 3 group during any CPR time interval. However, base changes were significantly improved in the 15 to 20 minute CPR time interval ( P ≤ .05). Because only resuscitated patients were evaluated in this study, no determination could be made regarding bicarbonate's influence on survival following cardiac arrest. We describe the incidence of alkalosis, metabolic alkalosis, hypernatremia, and survival in patients receiving HCO 3 and not receiving HCO 3 who were successfully resuscitated from prehospital cardiac arrest.