Association of Clinical Hypoperfusion Variables With Lactate Clearance and Hospital Mortality.

Background: Lactate has shown utility in assessing the prognosis of patients admitted to the hospital with confirmed or suspected shock. Some findings of the physical examination may replace it as screening tool. We have determined the correlation and association between clinical perfusion parameters and lactate at the time of admission; the correlation between the change in clinical parameters and lactate clearance after 6 and 24 h of resuscitation; and the association between clinical parameters, lactate, and mortality.

Methods: Prospective cohort study of adult patients hospitalized in the emergency room with infection, polytrauma, or other causes of hypotension. We measured serum lactate, capillary refill time, shock index, and pulse pressure at 0, 6, and 24 h after admission. A Spearman's correlation was performed between clinical variables and lactate levels, as well as between changes in clinical parameters and lactate clearance. The operative characteristics of these variables were determined by area under the receiver operating characteristic curve analysis and the association between lactate, clinical variables, and mortality through logistic regression.

Results: A total of 1,320 patients met the inclusion criteria, 66.7% (n = 880) confirmed infection, 19% (n = 251) polytrauma, and 14.3% (n = 189) another etiology. No significant correlation was found between any clinical variable and lactate values (r < 0.28). None of the variable had an adequate discriminatory capacity to detect hyperlactatemia (AUC < 0.62). In the multivariate model, lactate value at admission was the only variable independently associated with mortality (OR 1.2; 95% CI = 1.1-1.1).

Conclusions: Among patients with hypoperfusion risk or shock, no correlation was found between clinical variables and lactate. Of the set of parameters collected, lactate at admission was the only independent marker of mortality.