Effect of perioperative magnesium sulfate and labetalol infusion on peripheral perfusion and postoperative pain in nasal surgery: a randomized controlled trial

BACKGROUND: Maintenance of adequate peripheral perfusion during controlled hypotension is necessary for patient safety and improved surgical outcomes during controlled hypotension in nasal surgery. The hypothesis of this study was to investigate the effect of perioperative magnesium sulfate and labetalol infusion on peripheral perfusion and postoperative pain in patients undergoing nasal surgery. METHODS: A total of 50 patients were randomly assigned into two equal groups in this double-blind clinical study: the magnesium sulfate group; received 40 mg/kg loading dose of intravenous (IV) magnesium sulfate followed by 10–15 mg/kg/h continuous IV infusion and the labetalol group; received 0.25 mg/kg loading dose of IV labetalol followed by 0.5–1 mg/kg/h continuous IV infusion to achieve a mean arterial blood pressure (MABP) of = 55–65 mmHg. The primary outcome was to compare the effect of perioperative magnesium sulfate and labetalol infusion on peripheral perfusion during nasal surgery. The secondary outcomes were the assessment of serum lactate, postoperative pain, time to the first call for pethidine (rescue analgesic) and total pethidine consumption. RESULTS: PPI was comparable between the groups at baseline, intubation, and 5 min. In contrast, magnesium sulfate group had a significantly higher PPI than the labetalol group. The magnesium sulfate group had a significantly higher MABP and heart rate compared to labetalol group. The time to reach the target MABP was significantly prolonged in magnesium sulfate than the labetalol group [21.6 ± 1.7 vs 6.9 ± 1.5] min. VAS scores were significantly lower for 2 hs postoperatively in the magnesium sulfate group than the labetalol group. The time to first call of pethidine was significantly prolonged in the magnesium sulfate group compared to the labetalol group [113.1 ± 5.2 vs 28.2 ± 1.5] min. CONCLUSIONS: Magnesium sulfate maintains wider PPI and offers better postoperative pain relief compared to labetalol during induced hypotension in nasal surgery. TRIAL REGISTRATION: Institutional review board approval (ref: 6601/20–12-2020). Clinicaltrial.gov (ref: NCT04688203, date of registration: 29 -12–2020). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13037-022-00336-7.