Clinical assessment of plasma volume may be valuable during treatment in patients with decompensated heart failure, as stable patients receiving conventional therapy appear to have contracted plasma volume.
Stable chronic heart failure on conventional therapy may be associated with contracted plasma volume, contrasting with the widely held belief of long-term hypervolemia, which has implications for the use of diuretics versus inotropes or renal vasodilators.
Plasma volume, the intravascular portion of the extracellular fluid volume, can be measured using standard dilution techniques with radiolabeled tracer molecules. In healthy persons, plasma volume remains relatively constant as a result of tight regulation by the complex interaction between neurohormonal systems involved in sodium and water homeostasis. Although chronic heart failure (CHF) is characterized by activation of many of these neurohormonal systems, few studies have evaluated plasma volume in this condition under treatment. Untreated edematous decompensated heart failure (HF) is associated with a significant expansion of plasma volume. Patients with stable CHF, receiving conventional therapy, appear to have a contracted plasma volume, a concept that is in contrast to the widely held belief that CHF is associated with long-term hypervolemia. It is likely that significant changes in plasma volume occur during intensification of medical therapy or during transition from the edematous to the stable state. Clinical assessment of plasma volume may be of particular value during treatment in patients with decompensated HF, in whom the plasma volume is contracted despite an increase in total extracellular fluid volume. Under these circumstances, treatment with inotropes or renal vasodilators may be more appropriate than intravenous diuretics alone. Further studies evaluating plasma volume in HF may help to improve our understanding of the pathophysiologic mechanisms occurring in the development and progression of this complex condition.
Kalra et al. (Sat,) conducted a review in Heart failure. Clinical assessment of plasma volume may be valuable during treatment in patients with decompensated heart failure, as stable patients receiving conventional therapy appear to have contracted plasma volume.