Variations in the gliding characteristics of 10-ml plastic syringes used to locate the extradural space by "loss of resistance" techniques.

The gliding characteristics were evaluated of 10-ml plastic syringes used to identify the extradural space by "loss of resistance" techniques. This was undertaken quantitatively, by measuring the force necessary to depress syringe plungers, and qualitatively, by examining travel characteristics in terms of the force applied, together with the rate and uniformity of plunger travel. An important cause of inadvertent dural puncture is the use of syringes with plungers that do not move freely; this study has identified wide variations between makes which may be of particular relevance to anaesthetists inexperienced in techniques of extradural analgesia.