Effects of Preoperative Infusion of Magnesium Sulfate on Postoperative Pain in Lower Abdominal Surgery



Kashefi P¹ ; Naghibi K¹ ; Fathi M² Show Affiliations
Source: Journal of Isfahan Medical School Published:2013

Abstract

Background: One of the most common postoperative complications is pain which is caused by tissue damage during surgeries. Many drugs, such as magnesium sulfate, are used to control postoperative pain. Magnesium sulfate has been reported to have analgesic effects. Pre-emptive analgesia is a treatment to control pain before a painful procedure. This study was conducted to understand the preemptive effects of magnesium sulfate. Methods: This double-blind clinical trial was conducted in Alzahra Hospital (Isfahan, Iran) in 2012. A total number of 92 candidates for lower abdominal surgeries were selected and randomly allocated to two groups of experimental and control (n = 46 each). One hour before the operation, the experimental group was infused with 50 mg/kg magnesium sulfate in 100 ml normal saline during 10 minutes. The control group received 100 ml normal saline through the same method. Vital signs, including pulse rate and blood pressure, were recorded in a checklist before, during, and 2, 12, and 24 hours after the operation. Postoperative pain was measured by a visual analogue scale (VAS) and a verbal rating scale (VRS). Patients with VAS scores of greater than 4 were injected with 0.1 mg/kg morphine or similar doses of other narcotics. The amount of injected narcotics during the first 24 hours and patient satisfaction were also recorded for all patients. Findings: The severity of pain at the second, 12th, and 24th postoperative hours was significantly lower in the experimental group than in the control group (P < 0.001). Conclusion: According to the results of the present study, magnesium sulfate can effectively decrease postoperative pain. It may thus be prescribed before operations when there are no contraindications.