Effect of Intrathecal Magnesium Sulfate Versus Intravenous Magnesium Sulfate on Postoperative Pain After Abdominal Hysterectomy

Effect of Intrathecal Magnesium Sulfate Versus Intravenous Magnesium Sulfate on Postoperative Pain After Abdominal Hysterectomy

The present study aims to compare the effect of adding IV magnesium sulfate versus magnesium sulfate to intrathecal hyperbaric bupivacaine in total abdominal hysterectomy regarding the duration of postoperative analgesia, hemodynamic stability, and complications.

Abdominal Hysterectomy (AH) is associated with an intense inflammatory response that can result in moderate to severe postoperative pain, sometimes difficult to control.

Postoperative pain can cause many complications such as restlessness, increased sympathetic activity, high blood pressure, and tachycardia. Opioids are effective analgesics; however, they produce unwanted side effects, such as respiratory depression, nausea, and vomiting. Nonopioid drugs can decrease opioid usage and dependency.

Different adjuvants have been added to local anesthetics to increase the duration of the regional anesthesia, decrease pain-relieving drugs, and delay the onset of postoperative pain.

According to numerous reports, Magnesium sulfate has analgesic effects and lowers opioid consumption in many surgeries especially abdominal surgeries.

The analgesic properties of magnesium are based on acting as a non-competitive antagonist of N-Methyl-D-Aspartate (NMDA) receptors in central nervous system and regulating the calcium influx into the cell. These properties avoid the central sensitization mechanisms due to the stimulation of peripheral nociceptive nerves In the spinal cord, magnesium sulfate decreases pain transmission by hyperpolarizing spinal interneurons via G-protein-mediated activation of potassium channels and by decreasing the release of the neurotransmitters (substance P and glutamate) from primary afferent terminals.

Adequate postoperative pain relief can enhance recovery and increase patient satisfaction.

Inclusion Criteria:

• Patients between 40-65 years old
• Patients with ASA clinical status I/II
• Patients eligible for abdominal hysterectomy
• Oncological surgery

Exclusion Criteria:

• Body mass index (BMI) ≥ 40/kg / m2
• Previous abdominal surgery (except cesarean section)
• Severe cardiovascular, renal, and hepatic dysfunction
• Contraindications to spinal anesthesia
• Neuromuscular diseases
• Inappropriate for spinal anesthesia
• Patient refusal