The significance of preoperative impaired sensorium on surgical outcomes in nonemergent general surgical operations

Abstract

Importance: With an aging population, preoperative assessment of the frail older adult requires evaluation beyond simply accounting for chronic diseases. Impaired cognition is a recognized characteristic of the frail older adult.

Objective: To examine the effect of preoperative impaired sensorium (IS) on general surgical outcomes.

Design, setting, and participants: Retrospective cohort study using data between January 2005 and December 2010 at academic and community hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program. Patients undergoing nonemergent general surgical operations were studied. Multivariable logistic regression involving 45 preoperative patient-level risk factors and comorbidities was used to calculate the conditional probability of having IS. Patients having and not having preoperative IS were matched on their propensity scores using a 1:1 greedy matching technique. Propensity score matching resulted in almost all (n = 1765) patients with IS uniquely matching to a patient without IS, resulting in a cohort size of 3530. Complication rates between patients with and without IS were compared.

Main outcomes and measures: Rates of postoperative complications and death following nonemergent general surgical operations.

Results: In total, 294 037 patients were studied, of whom 1771 (0.6%) had preoperative IS. Patients with IS were older and had more significant preoperative risk factors and comorbidities. As a result, unadjusted analysis found that 22 of 23 postoperative complications were significantly more likely to occur in patients with IS. Within the matched cohort, rates of postoperative pneumonia, ventilator dependence, progressive renal insufficiency, urinary tract infection, stroke, venous thromboembolism, and postoperative death continued to be significantly (P < .05) elevated in patients with IS.

Conclusions and relevance: Impaired sensorium significantly increases postoperative morbidity and mortality independent of other preoperative risk factors and comorbidities following nonemergent general surgical operations. Incorporation of impaired cognitive function into routine preoperative risk assessment and decision making could be an important addition to traditional risk assessment strategies.