O068 Magnesium, the anaesthetists’ friend during carotid endarterectomy (CEA)

Abstract

Abstract Introduction Magnesium can be used as an antihypertensive for CEA patients, with the added benefit of anti-arrhythmic and anti-convulsive effects without the negative chronotropic effect of classic antihypertensives. It however causes vasodilation and increased diuresis, possibly increasing post-operative vasopressor requirements. This study determines the postoperative haemodynamic impact of magnesium therapy on CEA patients. Methods A retrospective review of CEA patients’ medical records between April 2020 and December 2021 was undertaken. In our unit, the postoperative trigger for commencing vasopressors (metaraminol or noradrenaline) is a systolic blood pressure <110 mmHg. A comparison of the postoperative vasopressor requirements in patients given intraoperative magnesium {5g IV infusion over 20 min if SBP >170mmHg} with those not given magnesium therapy was made (using Chi-square test). A secondary outcome was to assess the development of new acute postoperative kidney injury (AKI) (eGFR <60 ml/min/1.73m2). Results Of the 89 CEA patients; 8 had incomplete data and 65% were over 70 years old. The Surgical Outcome Risk Tool (SORT) score identified 44 (53%) patients as high risk (>5% risk of perioperative mortality). There was no difference between the magnesium vs non-magnesium therapy groups postoperatively in vasopressor requirement. (p=0.38, X2=0.74) or AKI rates (n=14, 16.8%). Conclusion Organ perfusion and cardiac stability can be achieved perioperatively in CEA patients with magnesium therapy without increasing vasopressors requirement or renal impairment; making it a good first-line therapy for intraoperative hypertension.