Intranasal Insulin Before Surgery Curbs Postoperative Delirium in Elderly

By Megan Brooks

March 29, 2021

NEW YORK (Reuters Health) - Administration of intranasal insulin before gastrointestinal surgery helps protect against postoperative delirium in elderly patients, according to a randomized controlled trial conducted in China.

Mounting evidence suggests that "nasal administration of insulin may reduce the incidence of postoperative delirium by increasing cerebral blood flow, reducing inflammation, improving sleep-wake cycle disorders, reducing tau protein hyperphosphorylation, and amyloid-beta deposition," Dr. Gu Gong, with the The General Hospital Of Western Theater Command, in Chengdu, told Reuters Health by email.

Age is a key risk factor for postoperative delirium (POD), which may occur in up to 54% of elderly patients having surgery for GI cancer, the researchers note in the American Journal of Geriatric Psychiatry.

To their knowledge, this is the first clinical trial looking at the use of perioperative intranasal insulin for the prevention of POD.

The study included 90 elderly patients undergoing laparoscopic radical gastrointestinal tumor resection under general anesthesia. Patients were randomly and evenly split into a control group (0.5 mL saline administered intranasally) or an insulin group (20 U/0.5 mL insulin administered intranasally) for two days prior to surgery.

Patients who received preoperative intranasal insulin were significantly less likely to develop POD within five days of surgery (12.5% vs. 47.5%, P=0.001).

The incidence of POD was lower in the insulin group on the first (12.5% vs. 32.5%, P=0.032) and third postoperative day (2.5% vs. 20%, P=0.034). The incidence of POD decreased in both groups over time and was no longer significantly different on postoperative day five (0% vs. 10%, P=0.116).

Repeated intranasal insulin administration before surgery was associated with reduced levels of several proinflammatory markers including interleukin-6, tumor necrosis factor-alpha and interleukin-1-beta.

Intranasal insulin did not induce hypoglycemia or other serious side effects.

This study suggests that "nasal administration of insulin may have a positive effect on postoperative delirium in patients with general anesthesia," Dr. Gong said. "We are conducting further research on dosage. In order to better apply it in the perioperative period, a multicenter clinical trial will be implemented."

The study had no commercial funding and the authors report no conflicts of interest.

SOURCE: American Journal of Geriatric Psychiatry, online February 23, 2021.