Technical problems associated with the use of 32-gauge and 22-gauge spinal catheters.

Interest in the use of continuous spinal anaesthesia (CSA) has recently increased because of the availability of new, extremely thin catheters. In this study the use of 32-gauge (G) catheters was compared with 22-G catheters in operations on the lower limb and for the administration of intrathecal morphine in the postoperative period in 42 elderly patients. CSA succeeded in 34 cases and 8 patients were anaesthetised with a single-shot spinal method. No general anaesthesia was needed. Technical problems with the subarachnoid puncture with the 19-G needle caused two failures in the 22-G group. In a group of 20 patients, there were five failures with the 32-G catheter, as opposed to one failure with the 22-G catheter in a group of 20 patients. Associated with morphine injection through the 32-G catheter, the syringe or connector was inadvertently disconnected in four cases and a tear of the catheter wall was observed in one case. Such problems did not occur with the 22-G catheter. Postdural puncture headache did not occur, and there was no difference in the incidence of patient-reported postoperative complications between the two groups. It is concluded that both the insertion and maintenance of the thin (32-G) subarachnoid catheters are associated with more technical problems than the 22-G catheter.