Sedation versus General Anaesthesia


Advances in anaesthetic drugs mean many procedures can now be undertaken under sedation. Many patients find this decision quite difficult and I thought that a blog explaining the difference would be helpful.


General anaesthesia provides loss of consciousness or awareness together with pain relief. If you have a general anaesthetic you will be completely unaware from the start of anaesthesia until you regain consciousness in recovery. Sedation on the other hand is the use of drugs to remove or reduce anxiety.


Sedation is often employed by non-anaesthetists such as gastroenterologists. A working party was set up some 20 years ago to look at safety and stated that these people should only use one drug and should limit the dose such that patients continue to be able to talk to them. The media have used the terms conscious sedation or twilight anaesthesia but these are not medical terms.


As an anaesthetist I can safely give multiple drugs for sedation. Because I am able to administer a general anaesthetic, it is completely safe for me to give higher doses so that in effect we have a spectrum from being fully awake through to being drowsy or sedated through to general anaesthesia. However, the consensus is that with sedation, even administered by anaesthetists, we are not providing unconsciousness but merely reducing anxiety. If you are sedated for an operation you must assume that you will be awake and aware of your surroundings even though many patients have retrograde amnesia and cannot remember what happened afterwards. Sedation does not remove pain but the surgeon will inject local anaesthetic to numb the surgical area and control or eliminate pain


In the past we have used drugs such as Valium but there is increasing concern that these drugs may be harmful to the brain particularly in the young and the old and I no longer use them for sedation. The drugs I use are for all extensive purposes the same drugs as for general anaesthesia but at different doses. Although the evidence in the literature is that sedation carries a higher risk than general anaesthesia, a lot of the studies have been done in North America with office based surgery where the surgeon has also given the sedation. For sedation in the UK administered by a qualified anaesthetist there is no evidence that sedation is safer nor more dangerous than general anaesthesia.


The choice in the majority of cases remains with the patient:

Do you want to be awake or do you want to be completely unconscious?

If you do not like needles then anaesthesia is preferable because sedation will require the injection of local anaesthetic.

If you suffer from perioperative nausea or vomiting, sedation will be less likely to cause these symptoms

If you have true reflux (a dirty taste or fluid in your mouth when you lie down, not just indigestion) then sedation is unsafe and cannot be offered


If sedation is feasible, your surgeon will normally discuss this with you but the final decision is very much your choice. I will discuss your choice with you on admission and you do not need to make up your mind in advance. With both sedation and general anaesthetic you will need an adult to take you home and remain with you overnight and you will not be able to work until at least the next day.