Study the beneficial effects of oxygen blender during cardiopulmonary bypass in reducing lactate levels in patients undergoing open-heart surgery

Abstract

Serum lactate levels rise during Cardio-Pulmonary Bypass (CPB) surgery for a variety of reasons, including peripheral circulatory failure, haemodilution, or excessive use of inotropic agents. Additionally, it has been reported that elevated serum lactate levels during the perioperative period are strongly associated with the worst postoperative outcomes, including mortality.To find out the beneficial effects of an oxygen blender during cardiopulmonary bypass in reducing lactate levels in patients undergoing open-heart surgery.This Prospective comparative study was done on 150 patients who underwent open-heart surgeries. Patients were divided into group A-75 patients: with direct oxygen flow without oxygen blender, group B- 75 patients: with oxygen blender. The serum lactate levels during CPB, postoperative levels and outcomes were monitored and both the groups were compared.Average FIO2 of 38 % was enough to maintain PO2 of 168 mm Hg by using the oxygen blender with the flow rates. Group A showed severe hyperoxemia (p-value <0.0001) and hypocarbia, resulting in severe respiratory alkalosis during CPB and severe acidosis in the immediate postoperative period in most of the cases. Group B showed a significant reduction in the serum lactate value at CPB one hour with 3.1 mmol/l reductions, 3.8 mmol/L reductions at 2 hours and 4.4 mmol/L reductions at ICU arrival (p-value <0.0001).Serum lactate values reduced significantly in the patients with oxygen blender. Study proved that application of an oxygen blender during CPB improved the postoperative results following open-heart surgeries. The researchers conclude that using an oxygen mask was beneficial.