EFFECTS OF DIFFERENT DOSAGES AND MODES OF SODIUM-BICARBONATE ADMINISTRATION DURING CARDIOPULMONARY-RESUSCITATION

Systemic acidosis occurs during cardiac arrest and cardiopulmonary resuscitation (CPR). The present study investigated the effect of different modes of sodium bicarbonate administration on blood gas parameters during CPR. Arterial and venous blood gases were obtained during 10 minutes of CPR which was preceded by 3 minutes of unassisted ventricular fibrillation in 36 dogs. Following 1 minute of CPR, the animals received one of four treatments in a randomized and blinded manner: normal saline (NS), sodium bicarbonate bolus dose 1 mEq/kg (B), sodium bicarbonate continuous infusion 0.1 mEq/kg/min (I), and sodium bicarbonate bolus dose (0.5 mEq/kg) plus continuous infusion 0.1 mEq/kg/min (L + I). Eleven dogs completed NS, 8 B, 8 I, and 9 L + I protocol. Following NS infusion, both arterial and venous pH declined consistently over time. Significant differences compared with NS treatment in venous pH were observed at 12 minutes of ventricular fibrillation (L + I, 7.27 ± 0.05; NS, 7.15 ± 0.05; B, 7.20 ± 0.05; I, 7.24 ± 0.04, each bicarbonate treatment versus NS, and L + I versus B, (P < .05). The B group had an elevated venous PCO (mm Hg) concentration following 6 minutes of ventricular fibrillation compared with NS, L + I, and I groups (81 ± 14 versus 69 ± 10 versus 68 ± 10 versus 71 ± 8, respectively, (P = .07). Arterial pH and PCO values showed a similar trend as the venous data with the L + I group demonstrating arterial alkalosis (pH > 7.45) at 12 minutes of ventricular fibrillation. The authors conclude: (1) venous acidosis developed during NS treatment and worsened with duration of CPR; (2) the L + I group showed significantly improved venous pH at 12 minutes of ventricular fibrillation as compared with NS and B but at the expense of arterial alkalosis; (3) the I group also had a greater effect on venous pH than the NS and B groups, but without causing arterial alkalosis at 12 minutes of ventricular fibrillation; and (4) a continuous infusion of sodium bicarbonate may be the most desirable mode of administration for the prevention of venous acidosis during CPR; however arterial alkalosis may occur when an additional small bolus dose of bicarbonate is administered. Further studies are needed to determine if such dosing methods alter other clinical outcome parameters. © 1992.