Ketamine versus Dexmedetomidine for Postoperative Cognitive Dysfunction after Cataract Surgery: A retrospective Study

Abstract

Introduction and aim: Postoperative cognition is an important issue after different surgeries. Some anesthetic drugs suggested to protect against postoperative cognitive dysfunction (POCD) and others lead to increased POCD. With high rate of cataract in geriatric populations, it is essential to protect against POCD. The current work aimed to compare retrospectively between ketamine dexmedetomidine for protection against POCD.

Methodology: We retrospectively analyzed data of patients over the age of 60 years, with physical status (ASA II or III), between June 2019 and July 2020, who were submitted to cataract extraction. We included three equal groups (each 25 patients). Control group received normal saline; ketamine group received 0.3 mg/kg/h of ketamine by continuous infusion, and dexmedetomidine group received 0.5 μg/kg/h of dexmedetomidine by continuous infusion. All were adequately assessed preoperatively, and standard monitoring was prepared.  A simple objective computer-based test battery was used to assess the postoperative (PO) cognition, while PO pain was assessed by Numeric Rating Scale (NRS), and PO analgesia was assessed by Ramsay sedation score. In addition, hemodynamics and intraocular pressure were measured and documented.

Results: Patients of the three groups were comparable regarding patient characteristics, surgery duration and hemodynamics.  POCD was significantly higher among control than ketamine or dexmedetomidine groups (56% versus 28.0% or 16.0%). The sedation score was significantly higher in K- and D- groups when compared to control group directly post-surgery, and at 2 and 4-hours postoperatively. The PO pain was lower in K and D-groups directly postoperative and at 2 hours. Otherwise, there was no significant differences between groups regarding intraocular pressure (IOP) and postoperative complications.

Conclusion: The intravenous infusion of ketamine or dexmedetomidine in cataract surgery significantly reduces the POCD. This was achieved with preserved hemodynamic parameters and IOP. In addition, no significant complications were recorded.   .