Incidence of postoperative delirium in elderly ambulatory patients: A prospective evaluation using the FAM-CAM instrument.

BACKGROUND: While the incidence of postoperative delirium is high in aged hospitalized patients undergoing major surgery, little is known concerning patients undergoing ambulatory surgery.

OBJECTIVE: To determine the incidence of postoperative delirium in aged patients after hospital discharge from an ambulatory surgery unit.

DESIGN: Prospective observational study.

PATIENTS: Elderly patients (≥75 years) scheduled for a surgical procedure on an ambulatory basis.

INTERVENTIONS: Filling of the Family Confusion Assessment Method (FAM-CAM) questionnaire (11 items) during a phone interview of family caregivers on two separate occasions: five to three days before surgery, and three to five days after surgery.

MAIN OUTCOME MEASURES: The detection of acute onset and fluctuating course inattention, disorganized thinking, altered level of consciousness, disorientation, perceptual disturbances, and psychomotor agitation from the observations of family caregivers.

RESULTS: Signs of delirium appeared de novo in 2 of 141 patients (incidence 1.4%) in the postoperative period: a 80-years old man who was disoriented and had incoherent and illogical speech on postoperative day 1 of resection of a cephalic cutaneous melanoma under local anesthesia and sedation (midazolam, sufentanil, and propofol), and a 83-years old woman with a pre-existing mental confusion, who experienced visual and hearing hallucinations and had inappropriate behaviour on postoperative day 2 of cataract surgery performed under episcleral block. Both patients returned to their preoperative states within a few days.

CONCLUSIONS: Using the FAM-CAM instrument for the detection of postoperative delirium in ambulatory patients, the study showed that the incidence of cognitive changes in the ambulatory setting is very low. Among several putative factors, the lightness of the surgical procedure, the wide use of regional anesthesia, and the short hospital stay may be contributing factors to this result. The findings of this study need to be confirmed in a larger sample of patients.