Abstract

Subarachnoid pressure was monitored continuously during and after epidural blood “patch” in eight patients with postlumbar-puncture headache. Epidural blood patch (15 ml) was associated with more than a threefold increase in subarachnoid pressure immediately following the epidural injection. Acute relief of symptoms occurred with an injected epidural volume of 7.5-10 ml and a subarachnoid pressure of at least 50 mmH₂O. Subarachnoid pressures were sustained at more than 70% of the peak subarachnoid pressure observed, when measured 15 minutes following completion of the epidural injection.