Changes in intracranial pressure during machine and continuous haemofiltration

Nine consecutive patients with both fulminant hepatic failure and acute oliguric renal failure were treated either by daily machine haemofiltration (MHF), or by continuous arterio-venous haemofiltration (CAVHF). Six patients received a total of twenty treatments by MHF and four CAVHF, mean duration of treatment 56 hours, range 24-160. Intracranial pressure (ICP) was measured using a subdural catheter. During treatment with MHF, the mean ICP increased from 8.9 +/- 1.4 mmHg at the start of filtration to 14.8 +/- 2.1 mmHg at the end of treatment (p less than 0.05), whereas there was no corresponding increase during the same period of time with CAVHF treatment, the mean ICP fell, but not significantly from 19.4 +/- 4.8 mmHg to 11.2 +/- 2.3 mmHg. The mean ICP increased to greater than 25 mmHg on eleven occasions during treatment with MHF, requiring treatment with bolus mannitol or propofol, during the same period of treatment with CAVHF no such surges in ICP were recorded. This suggests that continuous haemofiltration is to be preferred to intermittent machine haemofiltration in the management of patients with acute hepatorenal failure.