Intraoperative MgSO₄ infusion protects oxygenation and lung mechanics in COPD patients during general anesthesia. A randomized clinical trial

Abstract

Background: The purpose of this study was to examine the effects of an intraoperative MgSO 4 infusion on arterial oxygenation and lung mechanics in patients with moderate COPD undergoing cancer larynx surgery under general anesthesia (GA). Our primary outcome was arterial oxygenation determined by the PaO 2 and PaO 2 / FiO 2. The secondary outcomes were lung mechanics (peak airway pressure, airway plateau pressure, dead space, lung compliance, airway resistance) and postoperative complications. Methods: In this randomized controlled double-blinded trial, 40 patients with an ASA classifications II and/or III who were diagnosed with moderate COPD and who were scheduled for cancer larynx surgery under GA were randomly allocated into two equal groups, the target (Mg group) and control group (C group). In the Mg group, 30 mg/kg of 10% MgSO 4 solution was administered intravenously for over 20 minutes as the loading dose, followed by the continuous infusion of 10 mg/kg/hr In the C group, the same loading and maintenance infusion rates were administered using 0.9% saline. Results: Unlike the C group (baseline "T0" to post-infusion "T1" interval 294 ± 97 vs 238 ± 71 mm Hg, respectively, P = .04 ± SD), the Mg group exhibited preserved intraoperative PaO 2 (T0 to T1 interval 271 ± 89 vs 257 ± 53 mm Hg, respectively, P = .54 ± SD) and PaO 2 /FiO 2 (C group T0 to T1 interval 404 ± 81 vs 349 ± 84, P = .04 and Mg group 394 ± 91 vs 379 ± 95, P = .61, respectively), and these effects were modest. Further, compared to the C group, the Mg group exhibited lower airway resistance, dead space, airway plateau pressure, and peak airway pressure, and higher dynamic compliance. The postoperative PaO 2 and PaO 2 /FiO 2 were higher in the Mg group compared to the C group. Conclusions: Intraoperative infusion of MgSO 4 in patients with moderate COPD undergoing laryngectomy surgery under GA produces mild perioperative protective effects on both arterial oxygenation and lung mechanics.

Effect of magnesium sulfate on oxygenation and lung mechanics in morbidly obese patients undergoing bariatric surgery: a prospective double-blind randomized clinical trial

“…These findings could help explain the positive effects of MgSO 4 infusions on dynamic compliance and dead space observed in this study. Our results are similar to those of a previous study conducted by Ahmed et al [ 20 ], which showed that an intraoperative infusion of MgSO 4 resulted in mild perioperative protective effects against both arterial oxygenation and lung mechanics in patients with moderate COPD following laryngectomy under general anesthesia.…”

“…Setting the power = 0.80 and α = 0.05 with using PASS 11 th release (Hintze, 2011) [24], a minimal sample size of 2 cases in each group was required to get statistically significant between assumed Δ PaO2/FiO2 (%) in MgSO4 and control groups -3.1 ± 0.2 and -12.2 ± 0.5 respectively (Ahmed et al, 2020) [20]. A sample size of 40 patients (20 in each group) was used to ensure that the sample was representative to our population.…”

“…Recently, intraoperative magnesium has been investigated in COPD patients with promising results [20].…”

“…A recent study found promising results regarding arterial oxygenation and lung mechanics with the administration of intraoperative magnesium in patients with COPD [ 20 ]. We hypothesized that magnesium supplementation could improve perioperative oxygenation and lung mechanics parameters in morbidly obese patients undergoing bariatric surgery.…”