Surgical Tribune Asia Pacific

Sedative may prevent delirium after surgery

By Surgical Tribune
October 25, 2016

BEIJING, China/LONDON, UK: A mild sedative could greatly reduce the risk of people experiencing delirium after an operation and help the brain recover and reset, according to new research findings. A study conducted by scientists at Imperial College London and Peking University First Hospital has suggested that sedating patients after they have undergone an operation may reduce the risk of postoperative delirium by up to 65 per cent.

Postoperative delirium usually strikes within the first two days of a person waking from general anaesthetic. The symptoms range from relatively mild, such as a patient not knowing his or her name or where he or she is, to more severe, such as aggressive behaviour, believing people are trying to harm him or her, or even suffering hallucinations. The condition may affect up to one in three people who undergo a major operation, and those over 65 are particularly at risk.

Co-lead author Daqing Ma, Professor of Anaesthesia and senior lecturer at the Department of Surgery and Cancer at Imperial College London, said: “Post-operative delirium is a huge challenge for the medical community—and incredibly distressing for patients and their families. In many cases patients become almost child-like, and do not understand where they are, what is happening, and become very upset. Hospital staff have also been injured by delirious patients becoming aggressive. However, we currently have no treatments options available for this condition.”

Delirium linked to dementia development

The causes are unknown, but one theory is that major surgery can trigger inflammation throughout the body and can spread to the brain in some cases. The risk of the condition increases with age, and it seems to strike more often when patients undergo major, lengthy operations. The delirium can last from a few hours to a couple of days, and some research suggests it may be linked to an increased risk of elderly patients later developing dementia.

In the new study, co-led by Prof. Dong-Xin Wang at Peking University First Hospital, researchers assessed 700 patients aged 65 or older who were about to undergo major surgery at the Beijing hospital. Half received a low dose of a sedative called dexmedetomidine after the operation as an infusion directly into a vein in their arm, while the other half received a placebo saline infusion. The patients received the infusion of sedative or placebo around 1 hour after surgery and for the next 16 hours.

This sedative, which is commonly used for medical procedures in humans and in veterinary medicine, leaves a patient relaxed and drowsy, but conscious. The drug is considered safe, as it does not affect breathing.

Both groups received the same general anaesthetic before undergoing their operation. They were then assessed for symptoms of delirium every day for a week after their procedure. In the placebo group, 23 per cent developed delirium. However, only 9 per cent of those who received the sedative developed the condition.

Dexmedetomidine mimics natural brain state during sleep

Scientists are still unsure of how the sedative works, but one theory is that it allows the brain to rest and recover immediately after surgery, explained Ma. “Previous studies have shown that patients who struggle to sleep after their operation—perhaps because they are in pain or on a busy, noisy ward—are at increased risk of delirium.” Ma added that dexmedetomidine seems not only to trigger sleep, but also to mimic the natural state the brain enters during sleep.

“Although other sedatives induce sleep, they do not trigger the natural ‘sleep state’ the brain requires to rest, reset, and recover.”

According to Ma, previous research suggested that the sedative may help prevent delirium, but this is the largest study to show such beneficial effects. In addition, the study confirmed there were no side-effects of the sedative.

Fewer postoperative complications and shorter hospital stay

Furthermore, the patients given the sedative had fewer postoperative complications than the placebo group did and were discharged from hospital earlier.

The team will now assess whether the sedative has long-term benefits.

The study, titled “Dexmedetomidine for prevention of delirium in elderly patients after non-cardiac surgery: A randomised, double-blind, placebo-controlled trial”, was published in the 15 October issue of The Lancet.

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