PURPOSE: The purpose of this study is to evaluate the clinical significances of lactate clearance in predicting mortality of patients with septic shock. We hypothesize that a high lactate clearance (LA-clearance) at 6 and 12 hours are associated with decreased deaths.
METHODS: Consecutive patients admitted to the MICU in a six-month period with the diagnosis of septic shock defined by the ACCP/SCCM Consensus Conference, were entered into a prospective, cohort study. Excluded are end-stage liver disease, renal failure on hemodialysis or creatine-clearance less that 25mL/sec, and negative lactate clearance. Patients’ demographic information, vital signs (temperature, heart rate, mean arterial blood pressure), central venous pressure, arterial lactate, liver function tests and coagulation studies were obtained. In addition, APACHE II scores, therapies given (amount of intravenous fluid, norepinephrine and dobutamine), and 28-day mortality were documented. Data were recorded at hours zero, 6 and 12. Lactate clearance was defined as the percent reduction in lactate from initial value. A positive value denotes a decrease and a negative value indicated an increase in lactate. Patient were followed until discharged or death within 28 days. Survivors were then compared to non-survivors.
RESULTS: 46 patients were enrolled, 25 males and 21 females, with mean age of 65.6 years. Overall in-hospital mortality was 47.8%. APACHE II scores were 18.4 in survivor and 24.8 in non-survivor. CVP and MAP were 15.6mmHg and 75.3mmHg respectively in survivors and 12.8mmHg and 68.9mmHg respectively in non-surviving patients. Survivors had shorter ICU length of stay: 28.1 days compared to 32.0 days in non-survivors. Both groups had similar INR and creatine. The LA-clearance at 6-hour was 50.7% in survivors and 22.9% in non-survivors, while at 12-hour it was 64.3% and 41.1%, respectively.
CONCLUSION: Early high lactate clearance in septic shock patients may signal increased tissue perfusion and resolution of hypoxia, and may be a marker of decreased mortality.
CLINICAL IMPLICATIONS: Our surviving patient had more IV-fluid and higher doses of pressor, so early aggressive interventions may increase lactate elimination and decrease mortality.
DISCLOSURE: Raymond Khan, None.