Bedside test for diagnosis of oedema fluid after extradural anaesthesia.

PURPOSE: To consider and differentiate oedema fluid from other fluids in the performance of epidural block. CLINICAL FEATURES: A patient underwent placement of an epidural catheter for vaginal delivery of twins. Following a loss of resistance technique using air a small amount of fluid was aspirated through the needle and subsequently through the epidural catheter. The epidural block and delivery followed uneventfully. After delivery oedema fluid oozed from the puncture site for a number of days. Laboratory investigation revealed that this fluid was of oedematous origin. Bedside determination of alkaline pH by Combur 10 Test M urine stick appeared to be a simple and useful test for distinguishing the oedema fluid from fluids of other possible sources. CONCLUSION: When performing an epidural blockade the return of fluid may be due to oedematous fluid. Differentiation of the pH by a simple bedside test can aid in the differential diagnosis and prevent unnecessary additional attempts at needle repositioning.

Vincristine-induced alterations in Schwann cells of mouse peripheral nerve.

The sciatic nerve of C57Bl mice was examined with a transmission electron microscope to study the ultrastructural alterations in Schwann cells following treatment with escalating doses of vincristine. Results indicated that the drug exerts a dose-related effect. Total doses up to 8 micrograms/mouse did not cause any visible damage to Schwann cells. Higher doses induced not only damage to individual cells, but also affected a greater percentage of them. The myelin sheath was the most affected organelle. Schwann cells of myelinated fibers showed greater damage than those of unmyelinated fibers.