Continuous veno-venous hemofiltration without anticoagulation in high-risk patients

Abstract

Objective: To study the safety and operative efficacy of continuous veno-venous hemofiltration (CVVH) without anticoagulation in patients at high risk of bleeding. Design: Prospective cohort study and comparison to control group. Setting: Tertiary, multidisciplinary intensive care unit. Patients: Forty hemofiltration circuits in 12 patients with severe acute renal failure (ARF) deemed at high risk of bleeding. Forty control circuits in 14 patients treated with low-dose pre-filter heparin infusion. Interventions: CVVH at 2 l/h of pump-controlled ultrafiltration without anticoagulation or saline flush in patients at high risk of bleeding. Collection of data at the bedside. Measurements and main results: Mean circuit life was 32 h (95% CI: 20–44.4) in patients receiving CVVH without anticoagulation. Forty-three per cent of filters lasted longer than 30 h. Circuit lifespan did not correlate with international normalized ratio (INR), activated partial thromboplastin time (APTT) or platelet count. There were no bleeding complications and azotemic control was not compromised by lack of circuit anticoagulation with a mean serum urea of 16.0 mmol/l (95% CI: 14.9–18.1) during treatment. A control group of consecutive similarly ill patients not at high risk of bleeding received low-dose pre-filter heparin (mean dose 716 IU; 95% CI: 647–785). Their mean filter life was 19.5 h (95% CI: 14.2–23.8), significantly shorter than in the study patients (p=0.017). Conclusions: Critically ill patients at high risk of bleeding who require continuous renal replacement therapy (CRRT) can be safely managed without circuit anticoagulation. This strategy minimizes bleeding risks and is associated with an acceptable filter life. CRRT without anticoagulation should be strongly considered in high-risk patients.