Elevation in serum lactate at the time of febrile neutropenia (FN) in hemodynamically-stable patients with hematologic malignancies (HM) is associated with the development of septic shock within 48 hours

Background: Hospitalized patients who develop febrile neutropenia (FN) are treated empirically with antibiotics due to a high risk of developing septic shock. Currently, there is no method to predict which patients are at greatest risk. This study was designed to determine whether serum lactate, measured at the time of FN, is associated with the development of septic shock in hospitalized hematologic malignancy (HM) patients. Results: Of the 547 patients enrolled, 46 (8.4%; 95% CI 6.2-10.9) developed septic shock. Baseline characteristics were similar between the groups. In univariate analysis, tachypnea (OR 5.9; 95% CI: 2.0-16.9, p = 0.001) and lactate (OR 18.4; 95% CI: 4.1-81.6, p < 0.001) were significantly associated with the development of septic shock. In multivariate analysis, lactate and tachypnea remained independently associated with the development of septic shock. By ROC analysis, lactate provided incremental prognostic value compared to vital signs alone. Methods: Vital signs and lactate were measured during episodes of FN. The primary endpoint was the development of septic shock. Using a prospective, nested, case-control design, controls were matched on length of stay at the time of septic shock to achieve 80% power to detect an OR of >= 2.5. Using logistic regression, we evaluated the association of vital signs and lactate with the subsequent development of septic shock. Conclusions: In FN patients, measurement of lactate during FN adds significant prognostic information about the risk of developing septic shock. Routine measurement of lactate may help identify patients who may benefit from increased monitoring and early intervention strategies.