Continuous spinal anesthesia versus single small dose bupivacaine–fentanyl spinal anesthesia in high risk elderly patients: A randomized controlled trial

Background
Greater numbers of patients are presenting for surgery with aging-related, pre-existing conditions that place them at greater risk of an adverse outcome. Hemodynamic instability due to high sympathetic block largely limits the use of conventional dose spinal anesthesia in high risk elderly patients. In this study we aim to compare the hemodynamic stability and the incidence of hypotension in continuous spinal anesthesia (CSA) versus single low dose spinal anesthesia (SD) in elderly high risk patients.
Methods
This prospective randomized blinded study was carried on 34 ASA III & IV elderly patients aged >75 years undergoing orthopedic lower limb surgery. The patients were randomly assigned to one of the study groups. Group CSA received intermittent dosing of local anesthetic solution via an intrathecal catheter using 0.5 ml of 0.5% isobaric bupivacaine increments and 0.5 ml of fentanyl (25 μg) while group SD single dose of 1.5 ml of 0.5% isobaric bupivacaine and 0.5 ml of fentanyl (25 μg). The study groups were compared regarding hemodynamic stability, incidence of hypotension and total ephedrine consumption.
Results
Incidence of severe hypotension was significant. 52.9% of patients in SD group experienced an episode of severe hypotension versus none of them in CSA group ( 0.033). Total dose of fluids infused was significantly more in the SD group. The use of ephedrine was significantly more in SD group.
Conclusion
CSA provided fewer episodes of hypotension and no severe hypotension versus SD 7.5 mg bupivacaine. CSA offers the added advantage of the ability to titrate dose of local anesthetic as needed while maintaining hemodynamic stability.