Microalbuminuria does not reflect increased systemic capillary permeability in septic shock

Objective: To investigate the correlation between microalbuminuria and extravascular lung water in patients in septic shock who require mechanical ventilation for severe respiratory failure. Design and setting: Prospective, observational, clinical study in the 20-bed intensive care unit of a university hospital. Patients and participants: 25 consecutive patients in septic shock and also in severe respiratory failure requiring mechanical ventilation. Interventions: Hemodynamic parameters and extravascular lung water were determined by single arterial thermodilution. Together with each hemodynamic measurement the PaO2/FIO2 ratio and urinary microalbumin to creatinine ratio (M:Cr) was measured. Serum C-reactive protein (CRP) and procalcitonin (PCT) levels were also determined daily. Measurements and results: The EVLW index was significantly high-er than normal throughout the study. Microalbuminuria was in the normal range on entry and remained so for the rest of the study period. Serum PCT and CRP levels were significantly higher than normal at every assessment points. No significant correlation was found between M: Cr and either EVLW or PaO2/FIO2. Conclusions: In this study patients in septic shock with significantly elevated EVLW had normal urinary M:Cr, and there was no correlation between M:Cr and EWLV, and PaO2/FIO2. Therefore based on the current results routine measurements of microalbuminuria to determine endothelial permeability cannot be recommended in critically ill patients.