COMBINED ACUTE RESPIRATORY AND RENAL-FAILURE - MANAGEMENT BY CONTINUOUS HEMODIAFILTRATION

Objectives: To study the impact of continuous hemodiafiltration (CHD) on the morbidity and mortality of acute combined respiratory and renal failure in critically ill patients. Design: Prospective clinical study. Setting: Intensive Care Unit of a tertiary institution. Patients: One-hundred fifteen critically ill patients with combined acute respiratory and renal failure. Interventions: Treatment of all patients with either continuous arteriovenous hemodiafiltration (CAVHD) or continuous venovenous hemodiafiltration (CVVHD). Measurements: Assessment of illness severity, measurement of plasma urea, serum creatinine, electrolytes and arterial blood gases prior to and during treatment. Duration of oliguria, ICU stay, hospital stay, and final outcome. Results: One hundred fifteen critically ill patients with combined respiratory and renal failure (mean APACHE II score, 28.1; mean number of failing organs, 4.1) were studied. Thirty-five were treated with CAVHD and 80 with CVVHD for a mean treatment duration of 13.1 days per patient (range 2-47). Blood urea concentration fell from a mean of 29.4 mmol/l to a mean of 19.1 mmol/l (P < 0.001) and the serum creatinine concentration fell from a mean of 520 mumol/l to a mean of 374 mumol/l after 24 h of therapy (P < 0.001). The A-a gradient fell from a mean of 301 mmHg to a mean of 242 mmHg (P < 0.05). Despite the high degree of illness severity and the need for vasoactive drug infusion in 105 patients (91.3%), survival to hospital discharge was achieved in 33 patients (28.7%). For patients who required > 72 h of combined mechanical ventilation, survival was 22% (22 of 100 patients). Complications of continuous hemodiafiltration were few and all related to arterial vascular access. Conclusions: In critically ill patients with combined acute respiratory and renal failure, continuous hemodiafiltration controlled azotemia without hypotension and with early improvement in gas exchange. Patients treated with this approach achieved promising survival rates. Our findings support the view that CHD is safe and effective and that it offers important advantages over intermittent hemodialysis. It may be the dialytic therapy of choice in critically ill patients with combined acute respiratory and renal failure.