Elevated serum levels of the intracellular enzyme LDH in sepsis might result from various mechanisms including cellular injury related to bacterial toxins, ischemia and cytotoxic-reactive oxygen species generated during reperfusion. The clinical and prognostic significance of elevated LDH in severe sepsis remains to be defined. We hypothesized that increased LDH in patients with severe sepsis and septic shock would reflect the extent of tissue injury and be associated with a worse prognosis.
Clinical data and outcome variables were extracted from the medical records of 82 adult patients admitted to the intensive care unit at the University of Oklahoma, Health Sciences Center or the Oklahoma City VA medical center with severe sepsis, for whom informed consent was obtained. Data are presented as mean ± SEM. Comparisons between groups were done using the Student t-test for continuous variables. Categorical variables were compared using the Pearson chi-square test. A p value <0.05 was considered statistically significant.
The LDH level was elevated in 65 patient (79%) on admission. Increased LDH was associated with more physiologic abnormalities (higher APACHE II score), and organ failure (higher MODS score), and a higher lactic acid, SGOT, creatine kinase, creatinine, and lower platelet count and plasma bicarbonate level (p<0.05) (Table -1VariableNormal LDH (n = 17)High LDH (n = 65)P ValueMODS6.75 ± 0.99.2 ± 0.40.02APACHE II23 ± 2.227 ± 0.80.05HCO3 (mEq/L)23.5 ± 1.918.7 ± 0.90.012SGOT (U/L)36 ± 8197 ± 520.001CK (μmol/L)96 ± 31997 ± 1570.04Platelets x103257 ± 27180 ± 140.004Lactate (mmol/L)2.1 ± 0.34.1 ± 0.60.03Creatinine (mg/dl)2.4 ± 0.82.9 ± 0.40.03). There was significant correlation between LDH and lactic acid levels (r =0.76; p<0.01), and between LDH and MODS score(r =0.6; p<0.01). Death was associated with a higher LDH level (656±79; p<0.001 vs. 369±72 U/L). LDH levels that are increasing 48 hours after ICU admission(observed in 37 of 82 patients) were sensitive (0.72) and specific (0.77) in predicting mortality.
Increased plasma LDH levels are commonly seen in patients with severe sepsis. It is a marker of cell injury which reflects the degree of tissue damage.
Failure to improve LDH levels at 48 hours is a strong predictor of mortality in patients with severe sepsis.
J.G. Zein, None.