Comparison of continuous spinal anaesthesia using a 32-gauge catheter with anaesthesia using a single-dose 24-gauge atraumatic needle in young patients

One hundred and twenty-eight ASA I-III patients less than 40 yr of age, undergoing orthopaedic or trauma lower limb surgery, were allocated randomly to receive either continuous spinal anaesthesia (CSA) using a 32-gauge polyimide microcatheter with a permanent stylet (Rusch/TFX Medical, Duluth, GA, USA) or single-dose spinal anaesthesia (SDSA) with a 24-gauge x 103-mm Sprotte spinal needle (Pajunk, Germany). Plain bupivacaine (0.5%) was used as the local anaesthetic. The initial doses were 1 ml (5 mg) of CSA and 3 ml (15 mg) of SDSA, while the re-injection doses were 1 ml (5 mg) in the CSA group. SDSA was quicker to perform: mean 4.4 (SD 1.6) min compared with 6.2 (2.6) min for CSA (P < 0.01). Times to onset and surgical anaesthesia were also significantly greater in the CSA group (P < 0.01). The quality of the block was better in the SDSA group (P < 0.05), but was associated with greater haemodynamic instability (P < 0.05). The segmental level of analgesia was significantly lower in the CSA group (median T10 (range T12-T8)) than in the SDSA group (T9 (T11-T5)) (P < 0.05). There were no significant differences in the incidence of postoperative complications, with two mild spinal headaches in both groups. We conclude that CSA using a microcatheter in young patients is difficult to perform and affords no advantages over SDSA with a small gauge atraumatic needle.