Background: Short acting spinal anaesthesia provides many of the desired properties for ambulatory surgery. Facilitating early mobilisation and optimising pain management are key elements of enhanced recovery after surgery for primary hip and knee arthroplasties. Our previous case series consisting of 43 patients demonstrated shortened time for leg movement compared with bupivacaine. However, the technique also caused 23% cases of intraoperative discomfort and general anaesthesia was required in 2% of cases. We investigated the effects of intrathecal clonidine as an adjuvant in improving the efficacy of prilocaine spinal anaesthesia.
Methods: We collected data on 18 patients planned for day case hip arthroplasties who received intrathecal prilocaine and 15mcg of intrathecal clonidine. Data from 43 patients who received only intrathecal prilocaine from our previously published case series was used as the control group. Data collected includes mean prilocaine dose, length of time to first report of pain, length of time to first lower limb movement, intraoperative events including intraoperative discomfort, conversion to general anaesthesia and hypotension requiring treatment.
Results: There were no differences in the median time for first report of pain or leg movement in both groups although these were not statistically significant. The incidence of intraoperative discomfort is reduced in the intrathecal prilocaine+clonidine group (P+C) at 11.1% compared to 23.3% in the intrathecal prilocaine (P) group. There was no incidence of conversion to general anaesthesia in the P+C group. 55.6% of patients in P+C group experience hypotensive episodes requiring treatment as compared to 14% of patients in P group.
Conclusion: The addition of intrathecal clonidine improved the analgesic profile of prilocaine spinal anaesthesia but it also caused more episodes of hypotension in our patients compared to prilocaine only spinal anaesthesia.