Is it normal to have hallucinations after heart surgery?

Elderly lady lying in a hospital bed having hallucinations

My friend suffered hallucinations after heart surgery. I’m waiting for bypass surgery – will this happen to me and how can I reduce the risk?

Dr Ben Gibbison says:

Hallucinations are very common in the early days after major surgery, such as heart surgery. It’s estimated that up to 40 per cent of people report hallucinations and other aspects of delirium following some types of surgery. They usually last for a few days and then get better, but can be worrying and confusing for yourself and your visitors.

Hallucinations are often worse at night when lights are dim.

Scientists think these hallucinations may be linked to the inflammatory response in the body after heart surgery. This is your body’s response to injury and its first step towards healing – similar to the swelling when you sprain your ankle. But after heart surgery this happens across your whole body and the hallucinations are just a symptom of the brain not working perfectly.

Things that make hallucinations more likely include anaesthetic drugs, strong painkillers, the noise of the intensive care unit and confusion as to whether it is day or night. Hallucinations are often worse at night when lights are dim and it’s easier to think you’ve seen things that aren’t there.

Who's more prone to hallucinations?

People who have heart valve surgery or other more complex surgeries are more prone to hallucinations than patients having bypass surgery. This is because the operations take longer, so they are under anaesthetic and on the heart-lung bypass machine for longer.

Older people and those living with cognitive impairment (difficulty in memory or thinking) may be at greater risk of hallucinations, but more research is needed as we don’t yet know why some people experience delirium and others don’t.

Although the hallucinations stop after a few days, the memories could last longer. If necessary, you can be referred for psychological support. Attending cardiac rehabilitation should give you the opportunity to access a psychologist and learn relaxation techniques.

If you’ve had confusion or hallucinations after surgery before, tell your doctor and anaesthetist in advance of your operation. They will monitor you closely and decide on the best way to look after you. You could ask family and friends to bring in items from home, such as photos, and to visit you regularly, to give you familiarity and reassurance.

Meet the experts

A headshot of Dr Ben Gibbison

Dr Ben Gibbison is a Consultant in Cardiac Anaesthesia and Intensive Care at University Hospitals Bristol and Senior Lecturer at the  University of Bristol. His research work includes looking at the effects of the stress hormone cortisol on people who have just had heart surgery.

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