COMBINED MEASUREMENT OF TISSUE-FLUID, BLOOD-VOLUME AND HEMODYNAMICS IN HEMODIALYSIS

During recent decades hemodialysis (HD) therapy has gained momentum.. However, one of the main problems induced by maintenance HD is the occ urrence of hypotension. Approximately 25 to 30% of patients display sy mptomatic hypotension during a regular session (1). In the course of a HD session uremic patients are exposed to rapid variations in body fl uid composition (2). The effect of these variations on the hemodynamic status of the HD patient is thought to be multifactorial. Due to the withdrawal of fluid by ultrafiltration (UF) directly from the intravas cular compartment blood volume (BV) will decrease. Compensatory mechan isms to minimize this decrease are the process of interstitial refill and alterations in the cardiovascular system. However, former studies have shown that compensatory mechanisms will often fail in chronic ren al failure patients (3, 4). In this review the possible causes of intr adialytic hypotension are reviewed. The factors which play a role in t he shortcomings of the cardiovascular response and the interstitial re fill during conventional HD will be discussed consecutively. Newly dev eloped non-invasive methods for the continuous surveillance of body fl uid balance and hemodynamics during HD are described. Two clinical stu dies in which these non-invasive techniques were used will be discusse d. The aim of this review is to make clear that all the variables of i mportance to monitor and prevent hypovolemia and hypotension are curre ntly available on a non-invasive basis.