Blood lactate: an excellent prognostic indicator in high-risk surgical patients

Objectives

To evaluate the prognostic value of blood lactate levels in high-risk surgical patients.

Methods

Forty-four consecutive patients admitted to a general ICU for high-risk non-cardiac post-operative care. We recorded blood lactate levels, mean arterial pressure (MAP), heart rate (HR) and PaO₂/FIO₂ ratio at admission, 12, 24 and 48 h. We also recorded SAPS II score, surgery duration, number of complications, length of ICU and hospital stay for all patients.

Results

39 patients survived, and 34 had no complications during their stay in the ICU. The survivors had blood lactate levels lower than the non-survivors at 12 (1.67 ± 0.8 vs 3.16 ± 1.7; P = 0.004) and 24 h (1.5 ± 0.7 vs 2.3 ± 0.6: P = 0.05) but not at the admission. The blood lactate levels decreased in the survivors (P = 0.002) but not in the non-survivors. Blood lactate levels was lower among non-complicated patients (none complication) at admission (2.12 ± 0.85 vs 3.21 ± 2; P = 0.01); 12 h (1.63 ± 0.8 vs 2.5 ± 1.6; P = 0.02) and 24 h (1.36 ± 0.47 vs 2.1 ± 0.9; P = 0.004). Blood lactate levels decreased in the non-complicated patients (P = 0.004) but not in the complicated patients. All others variables were not statistically different between groups. The length of ICU stay was greater in the non-survivors (P < 0.0001) but not the hospital stay.

Conclusion

Blood lactate level was the best prognostic indicator in our population when compared to other variables often used at bedside, including SAPS II score.