The Role of Emotional and Orientation Support in Prevention of Postoperative Delirium Among Elderly Surgical Patients - a Multiple-crossover Clinical Trial

The world population is constantly growing older, and life expectancy in the western world is well over 80 years. The older population suffers more severe comorbidities, yet needs more surgical care. Anesthesiologists and surgeons are therefore required to care for older and sicker patients, often undergoing longer and more complex procedures than in the past.

Delirium is one of the most common adverse events experienced by hospitalized elderly patients. It is defined as an acute and fluctuating state characterized by altered awareness, behavior, emotional state, or thinking, and is associated with other morbidities as well as with mortality. Postoperative delirium (POD) affects between 10% and 50% of elderly surgical patients, depending on patients' baseline morbidities, the type of surgical procedure, and the tools and criteria used for diagnosis. POD is certainly the most common postoperative complication in this patient population, and is strongly associated with other postoperative adverse outcomes and mortality. Many societies and task-forces now recommend routine screening for cognitive decline and delirium in the perioperative period.

Several risk factors have been identified to be independently associated with POD, such as age, sex, and preoperative cognitive level. Nonetheless, most of the known risk factors are not modifiable, and little is known regarding interventions that can potentially decrease the risk of POD.

The division of Anesthesia and Intensive Care in the Tel-Aviv Medical Center has been conducting a quality improvement project since 2019, in which all surgical patients 70 years or older having elective non-cardiac non-cranial surgery are screened postoperatively for POD using the validated 4A's test starting in the post-anesthesia care unit (PACU) and for at least two postoperative days. The participants are also screened for preoperative cognitive decline, and monitored for other significant postoperative adverse events. Nearly 2000 eligible patients have been analyzed to date.

POD incidence in our institution is over 14%, and the investigators found a strong association between preoperative cognitive decline and POD, as also demonstrated by others. Interestingly, the investigators also demonstrated a strong association between delirium diagnosis in PACU and a later diagnosis in the surgical ward, suggesting that screening for delirium as early as PACU admission is important.