INFLUENCE OF CONTINUOUS VENOVENOUS HEMOFI LTRATION ON THE HEMODYNAMICS OF CRITICALLY ILL PATIENTS

Objective: to investigate the effects of continuous venovenous hemofil tration on the hemodynamics of critically ill patients with multiple o rgan dysfunction syndrome. Design: prospective, descriptive study of h emodynamic, respiratory and clinical data. Setting: tertiary universit y referral hospital. Multidisciplinary Intensive Care Unit (ICU). Pati ents: 55 consecutive patients with multiple organ dysfunction syndrome (DODS) requiring venovenous hemofiltration who had invasive hemodynam ic monitoring for management of hypotension and/or hypoxemia. Interven tions: Hemodynamic profile was recorded immediately before, at 3 hours , 6 hours and 12 hours alter the hemofiltration was started (mean of 3 set data each time). Measurements and main results: Fifty live patien ts with MODS who required hemodynamic monitoring and CVVH were analyze d. The mean age was 46 + 17 years (range 18-77 years). All patients we re in marked positive fluid balance and were grossly edematous when CV VH was begun. All of them received inotropic support. Twenty of these 55 patients (36 %) recovered from their MODS, and survived to leave th e intensive care unit. All patients were hemodynamically stable during hemofiltration. Mean arterial pressure rose from a mean of 79 +/- 12 to 92 +/- 15 mmHg (p < 0,001); PaO2/FiO(2) index from 106 +/- 43 to 14 5 +/- 52 (p < 0,001); tissue oxygen uptake index from 172 +/- 50 to 20 7 +/- 60 ml/minm(2) (p < 0,01); and tissue oxygen extraction from 24 +/- 7 to 27 +/- 7 % (p < 0,01). There was a significant decrease in th e mean pulmonary venous to arterial shunt fraction (37 +/- 10 to 30 +/ - 9 %) (p < 0,01). Mean arterial pressure before starting treatment wa s reduced in the dying group, but rose during the treatment and remain ed stable. Systemic vascular resistance index was significantly reduce d in the dying group before starling treatment, but also rose after he mofiltration began. Conclusions: continuous venovenous hemofiltration is associated with a significant improvement in several hemodynamic an d respiratory variables in critically ill patients with MODS. We presu me that the mechanism of action involves the clearance of vasoactive m ediators. Further work is necessary to decide whether this technique c an reduce the high mortality oi this condition.