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 ∆H2 O. 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 51 Cr fixed on red blood cells at D2 and D7 .

RESULTS: The ∆Na+ or ∆H2 O 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 ∆H2 O. 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 ∆H2 O and predicts sodium and extracellular fluid overload.

TRIAL REGISTRATION: ClinicalTrials.gov: NCT01858675 in May 13, 2013.