Continuous spinal anaesthesia using a standard epidural set for extracorporeal shockwave lithotripsy

Continuous spinal anaesthesia (CSA) offers considerable advantages over "single shot" spinal or epidural anaesthesia since it allows titration of anaesthesia using small doses of local anaesthetics (LA). We evaluated the feasibility of CSA using a standard epidural set for extracorporeal shockwave lithotripsy (ESWL).

Charts of 100 consecutive CSAs for ESWL were retrospectively reviewed. Lumbar CSA was performed using a 20G epidural catheter through an 18G Tuohy needle. The CSA was preplanned, or followed inadvertent dural puncture. Small LA boluses were injected to achieve the desired sensory level of anaesthesia. Demographic data, anaesthetic duration, LA doses, the most cephalad sensory level to pinprick, arterial blood pressure, heart rate, use of systemic sympathomimetics and complications were recorded.

Mean age was 66.2 +/- 9.9 (SD). The ASA status was III-IV in 54.1% and 5.5% of the preplanned and inadvertent patients, respectively. In 85 anaesthetics, hyperbaric bupivacaine 0.1% (9.7 +/- 7.5 mg) was used as the sole anaesthetic. Sensory level was T4-T8. Maximal decrease in systolic and diastolic blood pressures and heart rate was 19.0 +/- 9.8%, 13.4 +/- 13.3%, and 7.2 +/- 11.7 respectively. Intravenous sympathomimetics were used in nine of 82 (11.0%) preplanned, and in six of 18 (33.3%) inadvertent anaesthetics. Post dural puncture headache appeared following two of 82 (2.5%) preplanned, and four of 18 (22.2%) inadvertent anaesthetics. No postanaesthetic neurological deficit was detected.

Continuous spinal anaesthesia, using a standard epidural set and hyperbaric bupivacaine is feasible for ESWL in high risk patients. Inadvertent dural puncture does not preclude CSA under these circumstances.