Canadian Journal of Anesthesia, Vol 17, 37-51, Copyright © 1970 by Canadian Anesthesiologists' Society

Continuous Epidural Analgesia: Experience with Mechanical Injection Devices

¹ Department of Anaesthesia, University of Western Ontario, London, Canada

Continuous epidural analgesia requires repeated injections or the continuous infusion of local anaesthetic solutions. Two commercially available infusion pumps have been used for continuous infusions and one of these was equipped with an electronic timing device for intermittent injections. An automatic refilling syringe of our own design was also used and is described in detail.

The results of long-term continuous epidural analgesia with mechanical injection devices in 135 patients are reviewed. In 76 per cent of these, completely satisfactory analgesia could be maintained in postoperative patients and other pain problems, e.g. pancreatitis, arterial insufficiency of the lower extremities, chest trauma, and malignancy. The complications encountered are discussed; the main problem was a tachyphylaxis to the local anaesthetic agents, i.e., a decrease in duration and intensity of the epidural block.

A technique using a 0.5 per cent Xylocaine with 1:400,000 adrenaline was employed in 15 of the postsurgical patients; the pain relief was less consistent when compared with the use of higher concentrations of the same agent while the total dosages required were similar.

In an additional 68 obstetrical patients the maintenance of the epidural block with intermittent injections proved more satisfactory than with a continuous infusion.

In our experience, mechanical injection devices provide a satisfactory means for the maintenance of continuous epidural analgesia.

Note:

Presented at the Annual Meeting of the Canadian Anaesthetists' Society, Toronto, Ontario, June 16-19, 1969.