THE ASSOCIATION OF INTRAOPERATIVE FACTORS WITH THE DEVELOPMENT OF POSTOPERATIVE DELIRIUM

PURPOSE: To examine the association of intraoperative factors, includi ng route of anesthesia, hemodynamic complications, and blood loss, wit h the development of postoperative delirium. PATIENTS AND METHODS: We studied 1,341 patients 50 years of age and older admitted for major el ective noncardiac surgery at an academic medical center. Data on route of anesthesia, intraoperative hypotension, bradycardia and tachycardi a, blood loss, number of blood transfusions, and lowest postoperative hematocrit were obtained from the medical record. Delirium was diagnos ed by using daily interviews with the Confusion Assessment Method, as well as from the medical record and the hospital's nursing intensity i ndex. RESULTS: Postoperative delirium occurred in 117 (9%) patients. R oute of anesthesia and intraoperative hemodynamic complications were n ot associated with delirium. Delirium was associated with greater intr aoperative blood loss, more postoperative blood transfusions, and post operative hematocrit <30%. After adjusting for preoperative risk facto rs, postoperative hematocrit <30% was associated with an increased ris k of delirium (odds ratio = 1.7, 95% confidence interval 1.1-2.7). CON CLUSIONS: Further study is required to determine whether transfusion t o keep postoperative hematocrit above 30% can reduce the incidence of postoperative delirium. (C) 1998 by Excerpta Medica, Inc.