A Comparative Study between Phentolamine, Magnesium sulphate and Dexmedetomidine for Controlled Hypotension during Spine Surgery

Background: Spine surgery involves a significant risk of blood loss, which is often overlooked in comparison to arthroplasty procedures involving the hips and knees. On the other hand, excessive blood loss can be a serious concern for both substantial fusion procedures and less intensive surgeries for severe deformities. Aim: For the purpose of contrasting the relative merits of phentolamine, magnesium sulphate, and dexmedetomidine with controlled hypotensive anesthesia in the context of spinal surgery. Subjects and methods: The subjects for this prospective, randomized, double-blind, comparative clinical trial were 90 patients admitted to AL-Hussein and Bab EL-Sharia, two of Cairo's Al-Azhar University Hospitals, from May 2023 to June 2025. Results: HR was insignificantly different prior to induction of anesthesia, after induction of anesthesia, 200min, 215min, and 230min, and at the end of surgery among the three groups. MAP was insignificantly different prior to induction of anesthesia, 75min, 200min, 215min, 230min, and at the end of surgery among the three groups. Conclusion: DEX achieved the most significant MAP reduction, best surgical field conditions, and lowest blood loss, but it also caused the highest rates of bradycardia (33.33%) and hypotension (40%), requiring frequent intervention. Phentolamine and Magnesium Sulphate maintained greater hemodynamic stability, with lower ephedrine use and fewer cardiovascular side effects. Oxygenation, ventilation, and metabolic parameters remained stable across groups. These findings suggest that while DEX optimizes surgical conditions, Phentolamine and Magnesium sulphate offer safer hemodynamic profiles, necessitating individualized drug selection based on patient risk factors.