Extended daily on-line HDF using maximum convective volume seems to improve the outcome of septic MOF, especially in the early phase. The investigated mode of treatment proved to be feasible, well tolerated and highly cost effective compared to conventional CRRT. At present, this procedure would be applicable at every ICU facility with nephrological support.

Background: Volume management during renal replacement therapy (RRT) in septic shock is always in the conflict between aggravating hypovolemia by undue ultrafiltration (UF) and insufficient reduction of fluid overload which is associated with adverse outcome. Relative blood volume (RBV) monitoring could be helpful for timely transition from fluid resuscitation to fluid removal. Methods: Data of RBV were continuously monitored and used for guidance of UF and fluid resuscitation in 21 consecutive patients with severe septic multiple organ failure. RRT was applied with extended daily hemodiafiltration for median 11 h (range 6-23). Changes in RBV were analyzed during the first 4 treatment sessions. Results: During 26 treatments, RBV monitoring revealed an internal volume loss substituted by a median infusion volume of 2.38 l (maximum 8.07 l) per treatment to keep the RBV constant. In the remaining 40 sessions, a median net-UF of 1.00 l (range 0.40-4.40) was achieved. In the first 2 days predominantly substitution was necessary whereas from the third day UF became increasingly possible. The 28-day survival rate was 81%. Conclusion: Blood volume monitoring proved to be an easy and feasible tool for safe guidance of fluid management maintaining the balance between UF and vascular refilling. Video Journal Club ‘Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=433415.

Recording the relative blood volume is a standard feature of modern dialysis devices, enabling feedback guidance of ultrafiltration and dialysate conductivity. Technically, the process is based on optical or ultrasonic methods. On the grounds of clinical evidence suggesting a malfunction of the optical hemoglobin (Hb)-dependent absorbance method in the presence of sodium changes, we compared the system with the ultrasonic method. Six patients underwent hemodialysis with a step sodium profile (140, 150, 130, and 140 mmol/L, hourly switch), with two dialysis devices featuring the optical and the ultrasonic blood volume detector, respectively. The ultrasonic system recorded a decreasing blood volume throughout the treatment. With the optical method, changes in dialysate sodium led to inverse deviations of the blood volume curve. In another treatment without profile administering, a bolus of hypertonic sodium led to the detection of a rapid 8.7% reduction in blood volume with the optical method, which was not observed with the ultrasonic device. Blood volume monitors using the optical absorbance device are influenced by osmotic changes. An increase in osmolality produces a paradox drop in the measured blood volume and vice versa rendering the monitor inappropriate for use in sodium profiling.

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Recording the relative blood volume is a standard feature of modern dialysis devices. Three different measurement systems are incorporated in currently available dialysis machines. The Gambro-Hospal group and Nikkiso feature blood volume monitors based on different optical methods. The Fresenius Medical Care machines perform blood volume monitoring with an ultrasonic method. On grounds of clinical evidence suggesting a malfunction of the optical methods in the presence of sodium changes, we compared these three systems. Under the tested conditions, both optical systems show opposite and nonplausible courses of blood volume changes. The ultrasonic system seems to be less susceptible to osmotic changes.