Lactate in Critically Ill Patients an Outcome Marker with Time

Introduction: Static derangements in lactate homeostasis during ICU stay have become established as clinically useful markers of increased risk of hospital and ICU mortality. Lactate indices or kinetic alteration of the anaerobic metabolism that makes it a potential parameter to evaluate disease severity and intervention adequacy is an inexpensive and simple clinical parameter that can be obtained by a minimally invasive means. Aim of Work: To assess the predictive value of dynamic indices of hyperlactatemia in the first twenty four hours of Intensive Care Unit (ICU) admission with the value of more commonly used static indices. Patients and Methods: The study included 40 critically ill patients above 18 years old of both sexes with Hyperlactamia (≥2mmol/L). Patients were divided into septic group (n=20) and low oxygen transport group (n=20) which include all causes of low-O2. Six lactate indices specifically relating to the first 24 hours of ICU admission was considered, three static indices and three dynamic indices. Results: There were no statistically significant differences among two groups regarding age, most of laboratory results including ABG and also the need for mechanical ventilation. Admission lactate was significantly higher in low-oxygen transport group than septic group [37.5±11.4 versus 30.6±7.8 p-value 0.034]. Maximum lactate was significantly higher in low-oxygen transport group (L.T group) than septic group p-value (0.044). On the other hand absolute lactate (mg) was higher in septic group p-value ( 0.001). Percentage change of lactate was higher in septic group (47.8±11.3) than low-oxygen transport group (26.1±12.6) with highly significant p-value ( 0.001). Lastly, time weighted lactate was higher in low-oxygen transport group (1.72±0.81) than septic group (1.05±0.8) with significant p-value (0.012). Regarding non survivors were higher in low-oxygen transport group than septic group in patients with age adjustment less than 45 years old, whereas were higher in septic group with age adjustment ≥55 years with high statistical significant p-value 0.002. Conclusion: In critically ill patients, time weighted lactate and percent in lactate change in the first 24 hours can be independently predictive factor in ICU mortality. Also, a rising compared to a falling blood lactate concentration over the first 24 hours can be associated with significant increase in the risk of mortality.