How does anaesthesia work?

Posted on 12 March 2013

Pain-free major surgery and minor medical procedures are made possible by anaesthetic drugs administered by an anaesthetist. We answer some frequently asked questions.

What are some common side effects of general anaesthetic?
Around 33% of patients experience nausea and vomiting immediately after surgery, which could last for up to a day. Some people are concerned about shivering, but this usually only lasts briefly before body temperature returns to normal. Drowsiness, dizziness or confusion may also temporarily occur and are nothing to be concerned about.

Why are some people hysterical or aggressive afterwards?
‘The first thing I remember was sobbing uncontrollably, like the world was about to end. I was inconsolable, felt confused and couldn’t understand why,’ recalls Capetonian Catherine Martin of waking up after surgery to have impacted wisdom teeth removed under general anaesthetic. She had the same reaction several years later after the removal of her appendix. ‘It seems to be the way my body reacts.’

Anaesthetist Dr Hugo van Rensburg at Mediclinic Limpopo says everyone responds differently. ‘It’s hard to know how a patient will behave after general anaesthetic. Some are hysterical, aggressive or delirious; others are not. However these individual reactions do not last for very long, can be managed, and are not anything to be concerned about.’

What are the chances of waking up during surgery?
Called anaesthesia awareness, this is extremely rare and is experienced by one to two people of every 1 000 who undergo surgery under general anaesthetic. It can happen if one or more drugs are not administered in the correct amount, such as during emergency surgery where time constraints are involved. However brain activity, shown on a monitor, will show the patient’s awareness level so that preventative steps can be taken.

To find out more about the different types of anaesthesia, click here.

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The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.

Published in Patient Stories

In the interest of our patients, in accordance with SA law and our commitment to expertise, Mediclinic cannot subscribe to the practice of online diagnosis. Please consult a medical professional for specific medical advice. If you have any major concerns, please see your doctor for an assessment. If you have any cause for concern, your GP will be able to direct you to the appropriate specialists.

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