The Effects of Ketamine on Cognitive Function in Elderly Patients Undergoing Ophthalmic Surgery: A Pilot Study

Rascón-Martínez, Dulce M. MD, MSc; Fresán-Orellana, Ana PhD; Ocharán-Hernández, María E. PhD; Genis-Zarate, Jorge H. MD; Castellanos-Olivares, Antonio MD, MSc

doi: 10.1213/ANE.0000000000001153
Ambulatory Anesthesiology and Perioperative Management: Research Report

BACKGROUND: Acute postoperative cognitive dysfunction is characterized by neurocognitive dysfunction and confusion. In this study, we compared the cognitive status of a geriatric population undergoing ophthalmic surgery, as assessed by the Short Portable Mental Status Questionnaire (SPMSQ) before and after ketamine administration.

METHODS: Eighty patients were enrolled and randomly assigned in a double-blind study to receive either ketamine (0.3 mg/kg dose) or physiologic solution (control group). Sixty-five (control, n = 32; ketamine, n = 33) patients completed the trial. Cognitive performance was assessed with an abbreviated version of the SPMSQ. Measurements of analgesia, sedation, intraocular pressure, and hemodynamic variables were recorded.

RESULTS: With respect to cognitive performance, the baseline evaluation was similar for the control and ketamine groups. Postoperative evaluation showed an improvement only in the ketamine group. No increase in intraocular pressure or a secondary nystagmus was observed. The average dose of midazolam was higher in the control group, but the difference was not clinically significant. After surgery, analgesic behavior was better in the ketamine group than in the control group. There were no differences between groups in the sedation scale or in hemodynamic variables.

CONCLUSIONS: The administration of 0.3 mg/kg ketamine during ophthalmic surgery in geriatric patients changed their cognitive status as assessed by the SPMSQ, decreased the required dose of anesthetics, and produced no increase in intraocular pressure or in hemodynamic variables. However, because the evaluation only analyzed the immediate effects of the administered drug, further research will be required to examine the impact of ketamine on the postoperative cognitive performance of geriatric patients before the drug can be formally recommended for this purpose.

Published ahead of print January 14, 2016

From the *Department of Anesthesia, Hospital de Especialidades, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico; Clinic Research Division, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City, Mexico; Research Division, Escuela Superior de Medicina, Instituto Politecnico Nacional, Mexico City, Mexico; and §Department of Geriatrics, Hospital de Cardiología, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.

Accepted for publication November 20, 2015.

Published ahead of print January 14, 2016

Funding: This study was support by the Mexican Social Security Institute, and in part by the Clinical Research Division corresponding to the Superior Medicine School of the National Polytechnic Institute, Mexico City, Mexico.

The authors declare no conflicts of interest.

This study was previously presented as a thesis to obtain a Master’s Degree in Health Sciences for Dulce María Rascón Martínez to the Research Division of the Medical School of the National Polytechnic Institute.

Reprints will not be available from the authors.

Address correspondence to Dulce M. Rascón-Martínez, MD, MSc, Department of Anesthesia, Hospital de Especialidades, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ave. Cuauhtemoc 330. Colonia Doctores 06725, Mexico City, Mexico. Address e-mail to drarascon@hotmail.com.

© 2016 International Anesthesia Research Society