To evaluate the efficacy of bicarbonate Ringer′s solution applied in cardiopulmonary bypass (CPB) in cardiac surgery.

Sixty patients of both sexes, aged 55-75 yr, undergoing cardiac valve replacement under CPB, were selected and randomly divided into compound electrolyte solution group (group A, n=30) and bicarbonate Ringer′s solution group (group B, n=30). Group A was primed with 1 500 ml compound electrolyte solution, group B was primed with 1 500 ml bicarbonate Ringer′s solution, and both groups were primed with 1 000 ml succinylated gelatin.Zero-balanced ultrafiltration was carried out during the rewarming stage.The replacement solution was compound electrolyte solution 2 000 ml in group A, and the replacement solution was bicarbonate Ringer′s solution 2 000 ml in group B. Sodium bicarbonate solution was continuously dripped into an intravenous blood storage tank during CPB, and the acid-base balance disorder was corrected according to the results of blood gas analysis.The peripheral venous blood samples or venous blood samples from the oxygenator were obtained for blood gas analysis before CPB, at 30 min of CPB, at 5 min after opening the ascending aorta for calcium supplementation, at the end of zero-balanced ultrafiltration, and at 5 min after termination of CPB.Venous blood samples were collected from the oxygenator before the start of zero-balanced ultrafiltration and at the end of zero-balanced ultrafiltration for determination of erythrocyte osmotic fragility and concentrations of 2, 3-diphosphoglycerate.

Compared with group A, PaCO₂, Ca²⁺ and HCO₃^-concentrations were significantly increased at 30 min of CPB and at the end of zero-balanced ultrafiltration (P<0.05), and no significant change was found in pH value, BE, Glu, Lac, serum Na⁺ , Cl^- and K⁺ concentrations, erythrocyte osmotic fragility and concentration of 2, 3-diphosphoglycerate in group B (P>0.05).

Bicarbonate Ringer′s solution can be safely and effectively used for CPB in cardiac surgery.

Sodium bicarbonate Ringer′s solution; Cardiopulmonary bypass; priming; ultrafiltration