The Effect of an Intravenous Bolus of Ultra-Low-Dose Naloxone on Intraoperative Sedation, Post Operative Pain Intensity and Morphine Consumption in Cesarean Section Patients under Spinal Anesthesia

摘要

Different drugs from various pharmacological classes have been used to enhance postoperative opioid analgesia and reduce adverse effects. Animal studies have demonstrated that co-administration of an ultra-low-dose opioid antagonist with an opioid agonist may result in enhanced analgesia. Investigation of this effect in humans has been limited and produced inconsistent findings. In this study, 60 patients were randomized into 2 groups to receive either 2 mL saline (control group) or received IV dose of 100 ng kg 1 naloxone (diluted with normal saline to 2 mL) (naloxone group) after to the administration of spinal anesthesia (15 mg 0.5% hyperbaric bupivacaine). After administration of IV medication (saline or naloxone), sedation were scored with the Richmond Agitation-Sedation Scale at times 0, 5, 20, 30 min, respectivily. Following the surgery, patients were asked to score the pain (using 10-cm Visual Analog Scale (VAS) at the arrival in the ward and 2, 4, 8, 12 and 24 h, respectivily after surgery. The presence of Postoperative Nausea and Vomiting (PONV) and pruritus were recorded. All enrolled patients received post-operative intravenous analgesia delivered through a PCA pump. The demographic characteristics of patients, ASA physical status class, duration of surgery, basal VAS and basal sedation score were similar in the 2 groups. Total dose of morphine (38.3?10.7 mg in C group and 23.5?7.1 mg in N group, independent t test<0.001), the VAS pain score at time intervals (Mann-Whitney u test, p<0.001) and the intraoperative sedation score (Mann-Whitney u test, p<0.001) were significantly lower in the naloxone group. There were no significant differences in incidence of PONV and pruritus in groups.