High rate of early delirium after surgery in older adults

Close to half of older adults undergoing surgery with general anesthesia are found to have delirium in the postanesthesia care unit (PACU), according to a study in the August issue of Anesthesia & Analgesia, official journal of the International Anesthesia Research Society (IARS).

Delirium occurring early after surgery is linked to decreased cognitive (mental) function and an increased rate of nursing home admission, according to the study by Dr Karin J. Neufeld of Johns Hopkins University and colleagues. They write, "Recognizing delirium in the PACU may be important for identifying patients at higher risk of in-hospital harms…as well as cognitive impairment and institutionalization at hospital discharge."

Many Older Patients Have Delirium after Surgery

The researchers performed testing for delirium in the PACU (recovery room) in 91 older adults undergoing major surgery with general anesthesia. Delirium is defined as "acute change in level of consciousness, inattention, and disturbed cognitive function," and it's a common medical problem - especially in hospitalized patients.

The patients' average age was 79 years, and nearly 80 percent were living independently before their operation. All received widely used forms of general anesthesia for surgery.

On analysis by experts using standard diagnostic criteria, 45 percent of the patients had delirium in the PACU. In many cases, delirium persisted after the patient was moved to the hospital wards. Overall, about three-fourths of all cases of delirium occurring in the hospital after surgery started in the PACU.

Patients with early delirium had decreased mental function, with significant reduction on a standard cognitive test. The decline was significant even after adjustment for other factors, including initial cognitive score and duration of surgery.

Patients with early, persistent delirium were more likely to be discharged to a nursing home or other institution, rather than being sent home: 39 percent, compared to three percent of patients without delirium in the PACU. Of patients who had early delirium but were normal on the day after surgery, 26 percent were discharged to an institution.

A 'Common But Not Universal' Problem

The results show that delirium is a "common but not universal" problem for elderly patients undergoing surgery, according to Dr Neufeld and coauthors. They point out that 55 percent of patients did not have delirium in the PACU. Eighty percent of patients who were free of delirium in the PACU remained normal throughout their hospital stay.

But even brief episodes of postoperative delirium may have lasting effects in older adults, the study suggests. Dr Neufeld and colleagues note that many cases of delirium would have been missed if monitoring had started the day after surgery, rather than in the recovery room. They call for further studies of the rate and impact of early delirium after anesthesia and surgery, including evaluation of longer-term patient outcomes.