Etiological factors and clinical value of metabolic acidosis after cardiac surgery with cardiopulmonary bypass

Abstract

Aim – determine a forms of metabolic acidosis (MetAc) after cardiac surgery with cardiopulmonary bypass (CPB). Estimate significance of MetAc in an early postoperative period.Material and methods. We included the 129 adult cardiac surgery patients. We studied the indicators of acid-base blood status, markers of systemic inflammation, an oxygen delivery and consumption, the hemodynamic parameters, the clinical course of the postoperative period.Results. The acid-base disorders were found in 73.6 % of cases. The metabolic acidosis was in 51.2 % of cases: the lactate acidosis was in 92.4 % and the hyperchloremic acidosis was in 7.6 %. The metabolic lactate acidosis was represented by two forms: 1. the acid-base disorders due to a low cardiac output syndrome with a decrease in oxygen delivery and contractility (14.7 %); 2. the lactate acidosis due to a systemic inflammatory response syndrome (49.2 % of cases). It is associated with a high delivery and a low oxygen extraction, increased cardiac output and a vasoplegia. Patients with these disorders had a higher level of leukocytosis after 24 hours of the end the operation, had a longer duration of respiratory support and a long ICU stay and hospital stay.Conclusion. The lactate acidosis is represented by two forms: the lactate acidosis associated with the low cardiac output syndrome and lactate acidosis associated with the systemic inflammatory response. The lactate acidosis is a predictor of adverse outcome after cardiac surgery with CPB and associated with a postoperative complications and a mortality.