Influence of Low Dose Intrathecal Naloxone on Bupivacaine - Fentanyl Spinal Anaesthesia for Lower Limb Orthopedic Surgery in Elderly Patients

Abstract

Background: Fentanyl as an adjuvant in spinal anesthesia is known to potentate postoperative analgesia. However, its adverse effects decrease patient satisfaction. Objectives: This study evaluated the effect of adding low-dose intrathecal naloxone to bupivacaine-fentanyl spinal anesthesia on the incidence of pruritus. Patients and Method: In total, 92 patients who underwent lower limb orthopedic surgery under spinal anesthesia were randomly allocated into two equal groups. In the bupivacaine-fentanyl (BF) group, patients received spinal anesthesia with 12.5 mg hyperbaric bupivacaine 0.5% plus 25 µg fentanyl, whereas in the bupivacaine-fentanyl-naloxone (BFN) group, 12.5 mg hyperbaric bupivacaine 0.5% plus 25 µg fentanyl and 20 µg naloxone was administered. Postoperative Mini-mental state examination (MMSE), arterial blood gas analysis, analgesia, and sedation were recorded postoperatively. Results:The incidence of postoperative pruritus and other fentanyl-induced side effects was significantly lower in the BFN group than in the BF group in the first 4 hours postoperatively. The onset of sensory and motor blockade was not statistically significant between the two groups. In the BFN group, the duration of sensory blockade, motor blockade, postoperative analgesia, and the total postoperative analgesic requirements with no significant difference in MMSE scores between the two groups. Conclusions: The addition of low-dose naloxone to intrathecal BF in lower limb orthopedic surgeries in older adults is associated with fewer incidences of fentanyl-induced side effects and more analgesic efficacy with no influence on cognitive function.