Magnesium sulfate effectiveness for ERAS Protocols

Abstract

Magnesium sulfate has been considered a versatile anesthetic adjunct in the past, though its analgesic potential remains controversial. The discovery of its ability to block the N-methyl-D-aspartate receptor in the central nervous system has generated increasing interest in its use as a multimodal analgesic adjunct. Detrimental opioid-related side effects, as well a growing concern for opioid misuse, has heightened the desire to discover and use alternative agents for pain control. Many current Enhanced Recovery After Surgery (ERAS) protocols include intravenous (IV) magnesium sulfate as a component of the opioid-sparing anesthetic plan. In the featured case report, a 46-year-old morbidly obese female (BMI 42 kg/m2) presented for a robotic gastric sleeve for weight loss. This patient was at an increased risk for opioid-related adverse effects due to a history of obstructive sleep apnea and class III morbid obesity. As part of the facility’s ERAS protocol, the patient received celecoxib, acetaminophen, gabapentin, lidocaine, magnesium, fentanyl, ketamine, and ketorolac. Magnesium sulfate was given as a 2 g IV bolus after induction and prior to surgical incision. Throughout the maintenance phase, hemodynamic stability was maintained with 2 lactated ringers 250 mL boluses and 5 phenylephrine 100 mcg boluses for periods of hypotension. Vital signs were stable in the post-anesthesia care unit (PACU) with nonlabored spontaneous respirations and no dysrhythmias or ectopy. The patient was arousable and able to follow commands. When reassessed 45 minutes after PACU arrival, the patient was awake, alert, and resting comfortably. The patient had been weaned to room air and the SpO2 was 97%. The patient complained of occasional incisional pain with a numeric pain scale rating of 3/10 but did not request analgesics.