Early Changes in Intracranial Pressure During Haemofiltration Treatment in Patients with Grade 4 Hepatic Encephalopathy and Acute Oliguric Renal Failure

Abstract

We measured the intracranial pressure (ICP), using a subdural catheter in nine patients admitted with grade 4 hepatic encephalopathy due to fulminant hepatic failure complicated by oliguric renal failure. Six patients received daily machine haemofiltration and four patients were treated with continuous arteriovenous haemofiltration (CAVHF). The mean ICP increased during the first hour of machine haemofiltration from 9 +/- 1.4 mmHg to 13 +/- 1.8 mmHg (P less than 0.05), and there was a reduction in the mean arterial pressure from 92.4 +/- 2.7 mmHg to 81 +/- 3.2 mmHg (P less than 0.05) resulting in a reduction in cerebral perfusion pressure of up to 30%. The group treated by CAVHF, although having a greater mean ICP prior to treatment (19 +/- 4.8 mmHg) and a lower mean arterial pressure (66 +/- 3.6 mmHg) and consequently a lower cerebral perfusion pressure, did not show any increase in ICP or reduction in mean arterial or cerebral perfusion pressure. There was a significant reduction in serum osmolality during the first hour of treatment in the machine haemofiltration group (314 +/- 4 mOsm/kg to 309 +/- 4 mOsm/kg, P less than 0.05), whereas there was no corresponding change in the CAVHF group. This suggests that CAVHF is to be preferred for the treatment of acute renal failure in such patients who are at considerable risk of developing cerebral oedema.

Use of High-Flow Continuous Renal Replacement Therapy with Citrate Anticoagulation to Control Intracranial Pressure by Maintaining Hypernatremia in a Patient with Acute Brain Injury and Renal Failure

“…The CVP decreased from 17 mm Hg to 6 mm Hg during CRRT (figure 3). While previous data has shown elevated ICP with initiation of intermittent hemodialysis, 10 this was not observed in our patient. Other advantages offered by the continuous system included volume removal while maintaining stable CVP (6 to 10 mm Hg), constant solute removal, and maintaining electrolytes as desired by the involved teams.…”

“…This rapid change in osmotic gradient between brain tissue and vascular space leads to cerebral edema, which may cause dialysis equilibrium syndrome. 10 Early in the process, relative hypotension and headache may be the only warning symptoms. However, if not corrected, severe acute confusion and seizures can ensue.…”

Pearls & Oy-sters: The effects of renal replacement therapy on cerebral autoregulation

“…A previous report showed that rapid decrease in plasma osmolality during HD was associated with an increase in ICP. 11 Our patient had a dramatic decrease in serum osmolality on day 16 after HD, compared to previous days on HD (figure e-1 on the Neurology ® Web site at www.neurology.org). Rapid falls in serum osmolality is thought to be responsible for increases in brain edema and ICP crisis, invoking the reverse urea effect.…”

Continuous renal replacement therapy

“…4 Although meta-analysis has its limitations, none of the four included studies showed a renal benefit of CRRT. Jacka et al do not discuss why their retrospective study might differ from the available randomized trials.…”

“…Since the best available data do not indicate that dialytic modality influences outcome in critically ill patients, we suggest that the least costly therapy should be used until new randomized trials demonstrate otherwise. 4 CRRT is superior in correcting azotemia and acidosis and is recommended for patients with severe sepsis. 5,6 While we support Tonelli et al in …”