Predictive value of lactate in the postoperative period of cardiac surgery of the adult with extracorporeal circulation

Abstract

Introduction: Hyperlactacidemia is recognized as an indicator of metabolic function and plays a diagnostic and prognostic role in different clinical situations. However, studies in cardiac surgery are scarce and controversial.
Objective: To evaluate the predictive value of lactate as a prognostic indicator of morbidity in adult cardiovascular surgery and to identify the relationship between lactate levels, hematocrit, mean arterial pressure, intubation time and extracorporeal circulation time in patients operated on in the Cardiocentro of the Hospital ¨Hermanos Ameijeiras¨.
Methods: Investigation with prospective, descriptive and analytical design. The sample was represented by patients older than 18 years, of both genders, taken to cardiovascular surgery with extracorporeal circulation in the period from March 1 to June 30, 2015, taking into account as a selection criterion: to adult patients that they must be operated on for the first time from the heart and do not present liver diseases and chronic renal failure, or active sepsis; and as exclusion criteria: patients who must be reoperated for heart disease or patients with severe renal, or hepatic insufficiency and active infection. A form was designed to record the data of each patient, which was structured taking into account both the variables of study and their objectives and indicators.
Results: In the period considered, 24 patients were studied. 58% of the operated patients were classified with functional class III, the rest with functional class IV, with an average age of 58 ± 12 years, an average ejection fraction of 61%. 33% were women and 67% were men. More than half were hypertensive, 62%, 33% had kidney failure and only 3 patients were diabetic. The most performed surgical procedures were myocardial revascularization and mitral valve replacement, followed by aortic valve replacement and combined procedures. A statistical relationship was found between the different moments that the samples were taken, for the hematocrit, the mean blood pressure and the lactate.
Conclusions: The study showed that lactate levels increased during the first postoperative day is predictive of morbidity. A COR curve was constructed to justify the predictive value, and the best cut point that predicts a possible late complication is a serum lactate value of 3.4 mmol / L, with a sensitivity (66%) and specificity (70%) , the area under the curve was 0.784 with a statistical significance of p = 0.042. The patients with figures lower than this value had an evolution and exit of the intensive care unit of satisfactory cardiovascular surgery.