Renal replacement therapy in the patient with acute brain injury.

The patient with an acute brain injury requiring renal replacement therapy presents a major problem in that conventional intermittent hemodialysis may exacerbate the injury by compromising cerebral perfusion pressure, either after a reduction in cerebral perfusion or because of increased cerebral edema. Compared with standard intermittent hemodialysis, the continuous forms of renal replacement therapy (CRRT) provide an effective therapy in terms of solute clearance, coupled with improved cardiovascular and intracranial stability. The disadvantage of CRRT is that anticoagulation may be required, and anticoagulants with systemic effects may provoke intracerebral hemorrhage, either at the site of damage or around the intracranial pressure monitoring device. Although peritoneal dialysis does not require anticoagulation, the clearances achieved are often less than those of CRRT, and sudden changes in intraperitoneal volume may provoke cardiovascular and thus intracranial instability.