Intraoperative Infusion of Either Lidocaine or Dexmedetomidine on Regional Cerebral Oxygen Saturation and Postoperative Delirium in Elderly Patients Undergoing Abdominal Surgeries

Postoperative delirium (POD) is a significant complication in elderly patients undergoing major surgery, with an incidence ranging from 10% to 50%, depending on patient and surgical factors.

Regional cerebral oxygen saturation (rSO₂), measured using near-infrared spectroscopy (NIRS), provides a real-time, non-invasive marker of cerebral perfusion. Previous studies have demonstrated that intraoperative declines in rSO₂ are associated with an increased risk of POD.

Lidocaine, an amide local anesthetic, has been shown to reduce neuroinflammation, improve microcirculation, and exert neuroprotective effects. It has been associated with low postoperative pain, reduced opioid consumption, and improved cognitive outcomes.

Dexmedetomidine, an α2-adrenergic agonist, is known for its sedative, analgesic, and sympatholytic effects. It has been shown to enhance cerebral perfusion, improve rSO₂, and reduce POD incidence.

Inclusion criteria

• Age ≥ 65years old.
• Both sexes.
• Physical status classification of II - III according to the American Society of Anesthesiologists (ASA).
• Undergo elective non-cardiac surgeries.

Exclusion criteria

• History of mental illness, neurological illness, or scoring less than 8 using the abbreviated mental test (AMT) before operation.
• Severe hearing or visual impairment that may interfere with communication.
• Severe renal or hepatic dysfunction.
• Patients on central nervous system (CNS) medications (antipsychotics, anticonvulsants, antiparkinsonian, antidepressants).
• Contraindications to lidocaine or dexmedetomidine [e.g., allergy, severe bradycardia, atrioventricular (AV) block].