Association Between the Highest Lactate Level on the First Postoperative Day and Postoperative Delirium in Cardiac Surgery Patients

Abstract

Aims: The study aimed to determine the correlation between the maximum lactate on the first postoperative day and the incidence of postoperative delirium (POD) in patients after cardiac surgery. Methods: The data of cardiac surgery patients were extracted from the Medical Information Mart for Intensive Care IV database. The cut-off value for the first postoperative day maximum lactate was determined, and all patients were categorized into two groups according to the cut-off value. Propensity score matching (PSM) was applied between the two groups, and the difference in the incidence of POD was analyzed. Then, we employed univariate logistic regression, multivariate logistic regression, PSM, and inverse probability of treatment weighting (IPTW) models to examine the relationship between the first postoperative day lactate levels and POD. Results: Among the 4856 patients enrolled, there was a significant difference in lactate-max on the first postoperative day between patients without POD and patients with POD (median 2.5 vs. 3.1, p < 0.001). The cut-off value of lactate-max was 2.85 mmol/L. For the two groups after PSM, the incidence of POD in the lactate-max ≥ 2.85 mmol/L group was significantly elevated (19.2% vs. 15.9%, p = 0.029). The elevated lactate-max on the first postoperative day was substantially associated with an increased risk of POD in univariate and multivariate logistic regression analyses, PSM, and IPTW models. Conclusions: The results demonstrated that the first postoperative day lactate-max was correlated with the risk of POD in patients undergoing cardiac surgery, with the POD risk increasing significantly in patients with a lactate-max ≥ 2.85 mmol/L on the first postoperative day.