Normal-Range Blood Lactate Concentration in Septic Shock Is Prognostic and Predictive
Wacharasint P et al. – Lactate concentrations within the “normal” range can be a useful prognostic indicator in septic shock. Furthermore, patients whose lactate level is less than or equal to 1.4mmol/L may benefit from vasopressin infusion.Methods
- The authors conducted a retrospective analysis using the Vasopressin in Septic Shock Trial (VASST) as a derivation cohort (n=665), then validated using another single–center septic shock cohort, St Paul’s Hospital (SPH) cohort (n=469).
- Lactate levels were divided into quartiles.
- The primary outcome variable was 28–day mortality in both cohorts.
- They used receiver operating characteristic (ROC) curve analysis to compare the prognostic value of lactate concentrations versus Acute Physiology and Chronic Health Evaluation II scores.
- They then explored whether lactate concentrations might predict beneficial response to vasopressin compared with noradrenaline in VASST.
- Normal lactate range is less than 2.3mmol/L.
- At enrolment, patients in the second quartile (1.4<lactate<2.3mmol/L) had significantly increased mortality and organ dysfunction compared with patients who had lactate≤1.4mmol/L (quartile 1) (P<0.0001).
- Quartile 2 outcomes were as severe as quartile 3 (2.3≤lactate<4.4mmol/L) outcomes.
- Baseline lactate values (area under the ROC curve=0.63, 0.66; VASST, SPH) were as good as Acute Physiology and Chronic Health Evaluation II scores (area under the ROC curve=0.66, 0.73; VASST, SPH) as prognostic indicators of 28–day mortality.
- Lactate concentrations of 1.4mmol/L or less predicted a beneficial response in those randomized to vasopressin compared with noradrenaline in VASST (P<0.05).