title: The Effects of Ketamine on Cognitive Function in Elderly Patients Undergoing Ophthalmic Surgery: A Pilot Study.
abstract: 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.
authors.affiliation: 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.
authors.forename: Dulce M
authors.initials: DM
authors.lastname: Rascón-Martínez
authors.forename: Ana
authors.initials: A
authors.lastname: Fresán-Orellana
authors.forename: María E
authors.initials: ME
authors.lastname: Ocharán-Hernández
authors.forename: Jorge H
authors.initials: JH
authors.lastname: Genis-Zarate
authors.forename: Antonio
authors.initials: A
authors.lastname: Castellanos-Olivares
mesh_terms: D000368:Aged; D000700:Analgesics / Q000494:pharmacology*; D000778:Anesthetics, Dissociative / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects* / Q000502:physiology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D013508:Ophthalmologic Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D010865:Pilot Projects; D016896:Treatment Outcome
chemical_list: D000700:Analgesics; D000778:Anesthetics, Dissociative; D007649:Ketamine