Background and Goal of Study: Postoperative delirium (POD) is a complex clinical syndrome frequent after surgery. It has been associated with multiple risk factors such as comorbidities and other perioperative conditions. The aim of this study was to assess the incidence of delirium and identify risk factors for its development.
Materials and Methods: Observational prospective study approved by the Centro Hospitalar São João Ethics Committee and written informed consent was obtained. It was conducted in a Post Anesthesia Care Unit (PACU) during a 6-week period. Inclusion criteria were as follows: all consecutive adult Portuguese-speaking patients submitted to elective non-cardiac, non-obstetrics and non-neurological surgery admitted to the PACU; a total of 221 patients were enrolled to the study. Each patient included was evaluated for diagnosis of POD using the Nursing Delirium Screening Scale (NUDESC) in the PACU and on the first postoperative day in the ward at Hospital de São João. Demographic data and perioperative variables were recorded. Descriptive analysis of variables was used to summarize data and the Mann-Whitney U test, Fisher's exact test or Chi-square test were used. Multivariate analyses was done with logistic binary regression with calculation of Odds Ratio (OR) and its 95% confidence interval (95% CI).
Results and Discussion: The incidence of POD was 11%. Patients with POD were older (median age 69 versus 57 years, p< 0.001), were more likely to have higher ASA physical status (60% versus 19% for ASA physical status III/ IV, p< 0.001), had more frequently ischemic heart disease (24% versus 6%, p=0.001), hypertension (80% versus 45%, p=0.001), renal insufficiency (20% versus 5%, p=0.005), pulmonary chronic obstructive disease (20% versus 5.6%, p=0.009) and were more frequently on benzodiazepines medication (44% versus 25%, p=0.044). In multivariate analyses, age (OR 1.1, 95% Cl 1.0-1.1, p=0.003) and ASA physical status III/IV (OR 4.7, 95% Cl 1.9-11.5, p=0.001) were considered independent risk factors for delirium development after surgery.
Conclusion(s): Delirium was common in the post-anesthesia care after surgery. In this study, age and ASA physical status were considered independent risk factors for POD.