[The comparison of alkalizing methods in dogs during the immediate postresuscitation period]

The purpose of this study is to determine the effects of sodium bicarbonate (SB) on acid-base balance in dogs during immediate post-resuscitation period when tissue blood flow is decreased. Anesthetized dogs underwent 6 min of cardiac arrest plus 8 min of open chest CPR. Treatments with SB (0.1 mEq.kg-1.min-1), THAM (0.1 mEq.kg-1.min-1) and hyperventilation (TV = 20 ml.kg-1, RR = 20) were performed for 1h after restoration of spontaneous heart beat. Immediately after resuscitation, the following data were obtained; arterial (a) pH 7.17, PaCO2 37.8 mmHg, aHCO3- 13.2 mEq.l-1, venous (v) pH 7.09, PvCO2 57.5 mmHg, vHCO3- 16.6 mEq.l-1, CSF (c) pH 7.27, PcCO2 41.4 mmHg, cHCO3- 18.6 mEq.l-1, serum osmotic pressure (SOP) 310 mOsm.kg-1, and serum lactate (SL) 24.8 mg.dl-1. Metabolic acidosis in control group (no alkalizing agent, normoventilation) was not corrected within 120 min. In SB group, apH, aHCO3-, cpH and cHCO3- improved in 15-45 min after starting SB treatment. SL increased markedly (twice control group) which is attributable to CO2 production by SB in low flow state. SOP also increased to 320 mOsm.kg-1 by 120 min, with associated serum Na increase. In THAM group apH, PaCO2, aHCO3-, cpH and cHCO3- improved as in SB group. SOP rose to 324 mOsm.kg-1. No SL increase was observed. In hyperventilation group apH and aHCO3- were not normalized. PcCO2 and cpH were normalized earliest among the groups. SL changes were similar to that of control group. The author concludes that SB administration during immediate postresuscitation period may not be beneficial for treatment of acid-base balance.