Hemodynamic Effect of Dexmedetomidine Versus Magnesium Sulphate as an Adjuvant to Lidocaine in Preemptive Peribulbar Block in Patients Undergoing Dacryocystorhinostomy Under General Anesthesia

Hemodynamic Effect of Dexmedetomidine Versus Magnesium Sulphate as an Adjuvant to Lidocaine in Preemptive Peribulbar Block in Patients Undergoing Dacryocystorhinostomy Under General Anesthesia: A Randomized Controlled Trial

This study aims to compare the hemodynamic effect of dexmedetomidine and magnesium sulphate as an adjuvant to lidocaine in preemptive peribulbar block in patients undergoing Dacryocystorhinostomy (DCR) under general anaesthesia (GA) .

Dacryocystorhinostomy (DCR) is a delicate ophthalmic surgical procedure aimed at reestablishing the patency of the nasolacrimal duct in patients suffering from nasolacrimal duct obstruction (NLDO).

Magnesium is a non-competitive N-methyl-D-aspartate (NMDA) receptors antagonist, and it can decrease the excitatory post synaptic currents produced by activation of NMDA receptors and it inhibits voltage gated calcium channels.

Dexmedetomidine alpha-2 agonist, which stimulates both central and peripheral alpha-2 receptors which inhibits neuronal firing and inhibits release of C-fibers transmitters such as norepinephrine which inhibits nerve fiber action potential and explains the antinociceptive effects of dexmedetomidine.

Inclusion Criteria:

• Age ≥ 18 years.
• Both sexes.
• American Society of Anesthesiologists (ASA) physical status I or II.
• Undergoing elective Dacryocystorhinostomy (DCR) surgery under general anesthesia.

Exclusion Criteria:

• Patients have local infection.
• Allergic reaction or complications of the local anaesthesia (LA).
• Coagulopathy defined as international normalized ratio (INR) > 1.5, platelet count < 100,000/mm³, or ongoing anticoagulant therapy not adequately discontinued.
• Uncontrolled systemic disease, defined as poorly controlled hypertension [systolic blood pressure (SBP) > 160 mmHg], uncontrolled diabetes mellitus (HbA1c > 8.5%), unstable ischemic heart disease, or decompensated hepatic or renal disease.
• Uncooperative patients.