RESUMO
A combined spinal epidural anaesthetic (CSE), by design, produces a deliberate multicompartment block across a breached dural membrane. Since the lateral holes of the epidural catheter may lie in close proximity to the dural puncture site, a bolus solution of drug injected via the epidural catheter has the potential to leak through the dural puncture into the subarachnoid space. The aim of this study was to determine the incidence of intrathecal leak by performing an epidurogram. Fifteen patients undergoing surgery with a CSE anaesthetic using a 16 gauge Tuohy/26 gauge pencil point needle were studied. Within three hours of catheter insertion, 12 ml of contrast (iohexol 300 mg/ml) was injected via the epidural catheter under fluoroscopic control with screen recording and exposure of lateral and anteroposterior X-ray plates. All films were later reviewed for evidence of intrathecal spread. We did not observe any evidence of intrathecal spread of contrast. However, caution should be observed during administration of an intraoperative bolus dose of analgesic agent via a catheter inserted as part of a combined spinal epidural anaesthetic technique, particularly with the use of hydrophilic opiods.
