Delirium is a common, serious surgical complication in older adults. One in four adults will experience delirium after major surgery which can cause confusion, reduced awareness of the environment and difficulty maintaining attention. Delirium is distressing to patients, carers and family and is associated with prolonged hospital stay, poor outcomes after surgery and deterioration in physical and mental function.
The causes of postoperative delirium are complex. However, there is evidence to suggest that titrating general anaesthesia drugs to avoid overly deep anaesthesia may be a simple and effective way to reduce postoperative delirium. An electroencephalogram (EEG) measures the electrical activity of the brain and provides anaesthesiologists with information on how deeply anaesthesised a patient is and allows titration of general anaesthesia drugs during surgery. Using electroencephalography, this study will compare light and deep general anaesthesia to see if this could reduce delirium and later problems with brain function after surgery. In Australia, every patient affected by delirium costs an additional AUD$60,000 through direct healthcare needs, financial losses, and loss of wellbeing. If found to be effective, this simple intervention could help to preserve the brain health of many older adults undergoing surgery and save the health system millions of dollars.
Dr Carolyn Deng, Auckland City Hospital, New Zealand
Dr Douglas Campbell, Auckland City Hospital, New Zealand
Professor Tim Short, Auckland City Hospital, New Zealand
Professor Kate Leslie, Royal Melbourne Hospital, Victoria.
The project was awarded $A70,000 funding through the ANZCA research grants program for 2023.
Postoperative delirium (POD) is the commonest serious and preventable complication after surgery in older adults. POD is associated with increased hospital length of stay, discharge to long-term care facilities, memory loss, physical decline, and death. The risk of dementia in patients who experienced delirium is increased by 12-fold. There is evidence from previous scientific research to suggest titrating to a lighter plane of general anaesthesia using a brain monitor can reduce the likelihood of delirium afterwards. This study determines if having a lighter general anaesthetic for major surgery in older adults could reduce the chance of developing delirium after surgery compared to a deeper general anaesthetic.
The outcome of the study looks at whether the number of patients experiencing delirium after surgery is the same or different in the two groups (light general anaesthesia or deep general anaesthesia). Secondary outcomes look at related complications such as how severe the episode of delirium was, cognitive or brain function after surgery, physical decline after surgery, and death.
The ANZCA funds contributed towards the initial phase of the study which tested the feasibility of conducting a largescale study to test these hypotheses and ongoing recruitment for the main study.
The vanguard study recruited 76 patients across 3 international sites (Hong Kong, Christchurch, Auckland). We have made alterations to our protocol based on the results of the vanguard study, including simplifying our intervention to make it easier for clinicians to participate, changing our assessments to make each assessment quicker, internationally applicable, and able to be administered remotely.
We are continuing to recruit to the study in Hong Kong and New Zealand with 2 further sites ready to be initiated in the second quarter of this year.
There are no publications yet.