Persistent sepsis-induced hypotension without hyperlactatemia: is it really septic shock?

PURPOSE: The prognostic value of hyperlactatemia in septic shock is unquestionable. However, as current definitions do not include hyperlactatemia as a mandatory criterion, some hypotensive patients may be diagnosed as having septic shock despite exhibiting normolactatemia. The significance of persistent sepsis-induced hypotension without hyperlactatemia is unclear. Is it really septic shock? Our aim was to determine differences in outcome between patients diagnosed as having septic shock but exhibiting normal vs elevated lactate levels during evolution. We also explored the potential implications of including hyperlactatemia as an obligatory diagnostic criterion.
METHODS: We performed retrospective analyses on a cohort of 302 septic shock patients.
RESULTS: When we divided patients according to the presence of hyperlactatemia, 34% evolved without hyperlactatemia and exhibited a very low mortality risk (7.7% compared with 42.9% of those with hyperlactatemia). These patients also presented less severe organ dysfunctions and higher central venous O(2) saturation values, and required lower norepinephrine doses. The potential inclusion of hyperlactatemia in septic shock definition would reduce incidence in 34% but increase absolute mortality risk in 11%.
CONCLUSIONS: Persistent sepsis-induced hypotension without hyperlactatemia may not constitute a real septic shock. Our results support the need to review the current definition of septic shock. Hyperlactatemia could represent an objective parameter worth to be explored as a potential diagnostic criterion for septic shock.