Mid-regional pro-adrenomedullin (MR-proADM), a marker of positive fluid balance in critically ill patients: results of the ENVOL study

BACKGROUND The optimal control of blood volume without fluid overload is a main challenge in the daily care of intensive care unit (ICU) patients. Accordingly this study focused on the identification of biomarkers to help characterize fluid overload status. METHODS Sixty-seven patients were studied from ICU admission to day 7 (D7). Blood and urine samples were taken daily and sodium and water balance strictly calculated resulting in a total cumulative assessment of ∆Na+ and ∆H2O. Furthermore, plasmatic biomarkers (cortisol, epinephrine, norepinephrine, renin, angiotensin II, aldosterone, pro-endothelin, copeptine, atrial natriuretic peptide, erythropoietin, mid-regional pro-adrenomedullin (MR-proADM)) and Sequential Organ Failure Assessment (SOFA) scores were measured at D2, D5 and D7. Blood volumes were measured with 51Cr fixed on red blood cells at D2 and D7. RESULTS The ∆Na+ or ∆H2O were increased in all patients but never related to blood volumes at D2 nor D7. Total blood volumes were at normal values with constantly low red blood cell volumes and normal or decreased plasmatic volume. Weight, plasmatic proteins, and hemoglobin were weakly related to ∆Na+ or ∆H2O. Amongst all tested biomarkers, only MR-proADM was related to sodium and fluid overload. This biomarker was also a predictor of SOFA scores. CONCLUSIONS Plasmatic concentration in MR-proADM seems to be a good surrogate for evaluation of ∆Na+ or ∆H2O and predicts sodium and extracellular fluid overload. TRIAL REGISTRATION ClinicalTrials.gov: NCT01858675 in May 13, 2013.