Serial lactate and prognosis in intensive care patients

Introduction

Despite the fact that serum lactate (Lact) is a byproduct of anaerobic metabolism [1], its utility as marker of prognosis for patients in the intensive care unit (ICU) is still controversial [2,3].

Objectives

(1) To verify if the two first dosages of Lact were different between survivors (S) and nonsurvivors (NS), and (2) to verify whether there is difference between S and NS at ICU in relation to the temporal variation of Lact levels in the first 24 h of ICU admission.

Method

This was a prospective study includinsg all patients admitted to the ICU during a 3-month period. Lact measurements were done (mmol/l) at ICU admission (L_ADM) and in the in the 3 following days (L₁, L₂, L₃) according to the laboratory routine, making a total of until four measures per patient. The exclusion criteria were brain death at admission and patients who discharged or died before the L₁ dosage. Demographic data were collected. Lact was compared between S and NS in four ways: L_ADM; L₁; mean Lact; and variation between L_ADM and L₁ in time by calculating the area under the curve. Data were analyzed using the package Statistica v5.0^®. Means were compared using the nonpaired t-student test, and a P < 0.05 was considered statistically significant.

Results

A total of 90 patients were analyzed. Eleven (12%) were NS.

Conclusion

The dosages of Lact at admission, L₁, mean Lact and permanence of high levels of Lact in the first hours in the ICU were different between S and NS, suggesting that serial dosages of Lact may be a useful prognostic marker in ICU patients.

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