A prospective study of the feasibility of continuous spinal anesthesia in a university hospital.

A prospective study was undertaken in an elderly population undergoing orthopedic surgery to specifically study the feasibility of continuous spinal anesthesia (CSA). In a university hospital, 14 residents and 5 junior staff, using an 18-gauge needle and a 20-gauge catheter, performed 76 and 24 consecutive CSAs, respectively. There was an overall failure rate of 6%, all occurring in the residents' group. The causes affecting the success of CSA were inability to identify the subarachnoid space in 5/6 cases (all lumbar punctures were performed using the midline approach) and, in one case, inability to thread the catheter. The six failed CSAs were ultimately performed successfully by one of the senior authors. All surgeries were successfully performed with CSA, without requiring general anesthesia or intravenous narcotic supplementation. Anesthesia was initiated with isobaric bupivacaine in 94/100 cases. In 18% of patients, inadequate anesthesia prompted modifications of the local anesthetic solutions (i.e., type, baricity, total dosage) before surgery. One case of minor neurologic complication was observed, but no postspinal headache occurred. In conclusion, our findings led us to pursue CSA with large-bore equipment in an elderly population; furthermore, we believe that teaching the earlier use of alternative approaches other than the midline approach could further reduce our failure rate.