Alcohol-related predictors of delirium after major head and neck cancer surgery.

OBJECTIVE To identify specific alcohol-related predictors of postoperative delirium. DESIGN Inception cohort, logistic regression with step-wise selection. SETTING Ohio State University Comprehensive Cancer Center, Columbus. PATIENTS A total of 774 patients undergoing major resection of head and neck squamous cell carcinoma. MAIN OUTCOME MEASURES The correlation of 19 variables with postoperative delirium. One variable was an alcohol-related blood test: mean red blood cell volume (MCV). Eight variables were patient responses to alcohol-related questions. RESULTS Eighty-nine of 774 surgical procedures (11.5%) were complicated by delirium. Six variables were significantly associated with delirium: age older than 69 years (odds ratio [OR], 2.43; P < .01), preexisting cognitive impairment (OR, 3.83; P < .01), surgery duration greater than 6 hours (OR, 2.40; P < .01), MCV greater than 95.0 femtoliters (OR, 2.23; P < .01), ever being advised to cut back on alcohol (OR, 2.25; P = .01), and not abstaining from alcohol for at least 1 continuous week in the preceding year (OR, 2.16; P = .02). The number of variables stratified delirium risk (0 variables: 198 patients, 2.5% incidence of delirium; 1 variable: 278 patients, 6% incidence of delirium; 2 variables: 206 patients, 18% incidence of delirium; and >2 variables: 92 patients, 34% incidence of delirium). CONCLUSIONS Three clinical variables not related to alcohol drinking (age, preexisting cognitive impairment, and surgery duration), an alcohol-related laboratory test (MCV), and 2 alcohol-related questions ("At any time in your life, has anyone ever suggested that you should cut back on your drinking?" and "What is the greatest number of days in a row you have gone without an alcoholic drink in the past year?") may help in estimating a patient's risk for postoperative delirium.