RELATIONSHIP BETWEEN DIASTOLIC SHOCK INDEX AND SERUM LACTATE LEVELS UPON ICU ADMISSION IN THE IMMEDIATE POSTOPERATIVE PERIOD OF ELECTIVE CARDIAC SURGERY

Abstract

This article sought to evaluate the association between the Diastolic Shock Index (DSI) and serum lactate levels at admission to the intensive care unit (ICU) in patients undergoing elective cardiac surgery with cardiopulmonary bypass. This is a retrospective observational study that included 153 adult patients admitted to the ICU of a Brazilian tertiary care hospital between January 2022 and October 2025. The DSI was calculated as the ratio of heart rate to diastolic blood pressure, while serum lactate levels were measured during the first six hours of the postoperative period. A significant positive correlation was observed between DSI and lactate (r = 0.34; p < 0.001). Patients who died had higher lactate and DSI levels compared to survivors. Both markers also showed a positive correlation with length of stay in the ICU, while the DSI correlated positively with the dose of norepinephrine. After adjusting for age and sex, lactate remained independently associated with ICU mortality (OR 1.35; 95% CI 1.06–1.72; p = 0.02). We conclude that the combined assessment of DSI and lactate may contribute to the early identification of risk in the postoperative period.