The utility of hyperlactataemia in the definition of septic shock: evaluating the Sepsis-3 definitions in a sub-Saharan African intensive care unit

Background. Sepsis-3 definitions were published in 2016 and included hyperlactataemia (serum lactate >2.0 mmol/L) as a mandatory component of the new definition of septic shock. These data were collected mainly from high-income countries and lack adequate validation in scenarios outside these countries.Objectives. To evaluate admission serum lactate as a predictor of intensive care unit (ICU) mortality in patients with infection and hypotension requiring inotropic support.Methods. This was a retrospective observational study of 170 patients with infection and hypotension requiring inotropic support admitted to the ICU at King Edward VIII Hospital in Durban, South Africa. Admission serum lactate was evaluated as a predictor of ICU mortality in this cohort.Results. The study population had a median age of only 42 years. The ICU mortality rate for the cohort was 49.4%. Most patients were surgical (71.8%), with the most common source of sepsis being abdominal (55.9%). The ICU mortality rate was 40.9% in patients with a lactate level ≤2.0 mmol/L and 52.4% in those with a level >2.0 mmol/L; this did not reach statistical significance. The optimal cut-off was 4.5 mmol/L, at which there was a clear, statistically significant difference in mortality between patients without (39.3%) and with hyperlactataemia (59.3%)(p=0.009).Conclusions. Hyperlactataemia was associated with increased mortality. However, a lactate level >2.0 mmol/l, as proposed in Sepsis-3, did not reach statistical significance, and a higher cut-off of >4.5 mmol/L was more appropriate