Lactic acid and association with mortality in postoperative cardiac surgery. Retrospective cohort study

Objective: To analyse the behaviour of lactic acid in the first 24 h after surgery in cardiac surgery, and conditions associated with its elevation and impact on clinical evolution as a factor associated with mortality. Design: Observational, analytical, retrospective cohort study, repeated measures. Scope: 4-Level clinical cardiovascular intensive care unit in Colombia. Participants: Patients over 18 years of age who were admitted to the intensive care unit in the postoperative period of cardiac surgery with the need for extracorporeal circulation. Interventions: Measurement of lactic acid 0, 6, 12, 18 and 24 h after surgery. Variable of interest: Lactic acid, mediastinal bleeding, extracorporeal circulation time, aortic clamp time, overall in-hospital mortality. Results: A total of 214 people were included, the most frequent surgery was aortic change (43.9%), hypertension was present in 48.6% of the patients, the overall in-hospital mortality was 5.6%, the time of average hospital stay in ICU 3 days, during follow-up lactic acid was higher in those who died, with the greatest difference at 12 h, with the variables that influence the change in lactic acid were aortic clamp time, mediastinal bleeding >1000 cc, urea nitrogen and the use of two inotropes, the factors that increase the risk of mortality were lactic acid greater than 3 mmol/l RR 13.96 CI 1.55–125.9; p-value =.019, and mediastinal bleeding >1000 cc, RR: 2.55 (CI: 1.00-6.51), p-value =.049. Conclusion: Lactic acid was shown to be an associated factor for mortality at different times of monitoring, always higher in the people who died.