The Prognostic Value of Lactate in Cardiac Intensive Care Unit Patients With Cardiac Arrest and Shock

Abstract

Lactate is a prognostic marker in critically ill patients, although currently available illness severity scores do not include lactate as a predictive parameter. We sought to describe the association between lactate and hospital mortality in patients admitted to the cardiac intensive care unit (CICU) with cardiac arrest (CA) and shock. Retrospective observational analysis of Mayo Clinic CICU patients admitted from 2007 to 2018 with measured lactate on admission, including patients with and without CA or shock. We examined hospital mortality as a function of admission lactate in patients. Multivariable logistic regression was used to determine predictors of hospital mortality. We included 3,042 patients with a median age of 70 years (IQR 60-80), including 41% females, 26% with CA, and 39% with shock. The median APACHE-IV predicted mortality was 24% (IQR 11-51%), and the median admission lactate was 1.8 mmol/L (IQR 1.1-3.0). Hospital mortality occurred in 23% of patients and rose progressively with higher admission lactate, including in patients with and without CA or shock. After multivariable adjustment for clinical characteristics, therapies, and illness severity, a higher lactate remained associated with increased hospital mortality (adjusted OR 1.13 per mmol/L, 95% CI 1.06-1.20, P < 0.001). Admission lactate levels are strongly associated with increased hospital mortality among CICU patients, including those with and without CA or shock. The prognostic value of lactate levels is independent of established ICU prognostic scores and dependent on admission diagnosis, which may help inform clinicians caring for CICU patients.