Prognostic value of lactate clearance in severe community acquired pneumonia

IntroductionSevere community acquired pneumonia (SCAP) occurs in approximately 18–36% of all CAP and the mortality rate could be as high as 67% in patients with SCAP. Several studies have described a correlation between baseline lactate concentration and mortality of ICU patients.Aim of the workTo follow lactate clearance after admission for 24 h which could be an indicator of outcome in severe community acquired pneumonia.Patients and methodsForty-six consecutively admitted adult patients were diagnosed as severe community acquired pneumonia. Lactate was measured at the time of admission (H0), reassessment of lactate level was done after 8 h and also another lactate measurement done after 24 h. In a trial to follow the guideline for management and to optimize oxygen delivery (DO2) and reach a ScvO2 ⩾ 70%, ScvO2 was measured through a central venous blood sample done at the same time with lactate. During the study resuscitation by inotropic medications and patient’s physiological parameters were measured routinely. All data needed to calculate the Acute Physiology and Chronic Health Evaluation (APACHE II) score were recorded.ResultsMost of patients in the current study were above the age of 60 years. Twenty-five patients had lactate clearance of more than 40%, those patients were included in group 1, whereas 21 had lactate clearance of 40% or less and they were included in group II. There was no significant difference in the age and sex distribution between both groups. Out of 21 patients included in group II, inotropic drugs were used in 8 patients (38%), whereas there was one patient only in group 1. The rate of intubation in addition to the mean APACHE II score and ICU length of stay was significantly higher in group II compared to group I. Over the first 24 h three readings for mixed venous oxygen were recorded and included in the analysis. The reading of mixed venous oxygen recorded after 24 h of ICU admission was significantly high in group 1. All indices of blood lactate clearance over the first 24 h were higher in group 1 compared to group II, however it was only significantly high after 24 h (p-value 0.01).ConclusionOur study suggests that lactate clearance could be used as a useful biomarker which is inexpensive and a reliable predictor of patient outcome in critically ill patients admitted to ICU with severe community-acquired pneumonia.