EFFECTS OF ACID-BASE CORRECTION ON HEMODYNAMICS, OXYGEN DYNAMICS, ANDRESUSCITABILITY IN SEVERE CANINE HEMORRHAGIC-SHOCK

Objective: To compare the effects of hypertonic saline, sodium bicarbo nate, and Carbicarb(R) resuscitation on acid-base balance, hemodynamic s, and oxygen dynamics in a reperfused, canine hemorrhagic shock model . Design: Prospective, randomized trial. Setting: Laboratory at a univ ersity medical center. Subjects: Thirty-five anesthetized, mongrel dog s. Interventions: After the administration of anesthesia, the dogs wer e intubated and mechanically ventilated. Vascular catheters were inser ted into each femoral artery, for continuous blood pressure monitoring intermittent blood sampling, and for establishing controlled hemorrha ge. A pulmonary artery catheter was inserted via the right jugular vei n. Inhaled and exhaled gases were continuously analyzed using a metabo lic gas monitor. The animals were subjected to 90 mins of controlled h emorrhagic shock. They were then randomly given a 2.5-mL/kg equimolar injection of 8.4% sodium bicarbonate, Carbicarb, or 5.84% hypertonic s aline. The sodium load per kilogram of body weight was identical in al l three groups. Thirty minutes later, the animals were retransfused wi th the shed blood over 15 mins and further observed for 120 mins. Meas urements and Main Results: Carbicarb and sodium bicarbonate both signi ficantly increased bicarbonate concentrations compared with saline. Ar terial and venous blood pH increased more with Carbicarb than with bic arbonate but this increase was not statistically significant. After sh ock but before retransfusion, all three treatments moderately increase d blood pressure, cardiac index, oxygen delivery index, and oxygen con sumption index to a similar extent. After retransfusion, blood pressur e, cardiac index, and oxygen dynamics temporarily improved in all grou ps, without significant improvement in the bicarbonate and Carbicarb-t reated animals, despite their excellent acid-base status. Conclusions: In severe canine hemorrhagic shock, Carbicarb, bicarbonate, and hyper tonic saline appear to possess similar hemodynamic properties despite the buffering properties of bicarbonate and Carbicarb. The similar res ponses may be due to their identical sodium content. Arterial pH corre ction does not appear to further improve the responses to blood retran sfusion.