General Anaesthesia

///General Anaesthesia
General Anaesthesia2018-11-18T20:42:06+00:00

General Anaesthesia (GA) refers to being “put to sleep”. During GA, you are unconscious. This is different from conscious sedation: sedation means you can sort of communicate and your protective reflexes are intact. General anaesthesia means you can’t do either.

Can I get general anaesthesia for dental treatment?

General anaesthesia is rarely used for dental treatment nowadays. The main reason is that IV sedation with midazolam works so well for nearly everyone with severe anxiety, and is extremely safe.

Why has general anaesthesia for dental treatment gone out of fashion?

In 2000, the Department of Health (England) published a report entitled A Conscious Decision. They wrote this guidance because conscious sedation had emerged as a reliable and safe alternative to general anaesthesia, without the risks associated with general anaesthesia outside a hospital environment. The guidance was also adopted in Scotland, Wales and Northern Ireland.

The guidance states that GA for dental treatment in adults should only be used as a last resort, and that conscious sedation should be used in preference to GA whenever possible. When GA is considered necessary, it should be given in the safest way possible. This means that GA nowadays cannot be provided at dental practices, and is only available in hospitals or specialist clinics which have critical care facilities.

GA must only be provided by someone who is:

  • on the specialist register of the General Medical Council as an anaesthetist
  • a trainee working under supervision as part of a Royal College of Anaesthetists’ approved training programme, or
  • a non-consultant career-grade anaesthetist with an NHS appointment under the supervision of a named consultant anaesthetist, who must be a member of the same NHS anaesthetic department where the non-consultant career grade anaesthetist is employed.

The anaesthetist must be supported by a health professional who is specifically trained and experienced in the necessary skills to help monitor the patient’s condition and to assist in an emergency.

This policy change has resulted in far fewer GAs being given, and in an increase in the use of IV conscious sedation.

Any technique which can result in the loss of consciousness is defined as GA, and in the UK ‘deep sedation’ is considered to fall into this category. This includes some of the techniques mentioned on our IV sedation page, such as the use of propofol.

Ask a Dentist: Are there any other reasons why general anaesthesia isn’t used much for dental treatment?

Although the risk of serious complications (including death) is exceedingly small in a healthy adult, GA has some major disadvantages when it comes to dental work, especially anything other than extractions. Here’s why:

“It’s possible to do complex treatment under GA, however, it’s not common. Here’s why… if you do a crown prep for instance, how do you fit the crown? Bring the patient back in 2 weeks later for another GA and fit the crown? What happens if the temp crown fails?

Similarly, what happens if you’ve done a really big filling or a crown prep and it blows up after? Another GA for a RCT/extraction, if you do an RCT and that fails? Another GA… multiple GAs over a short period are much riskier than a one-off.

So current practice is, KISS (keep it simple, stupid). GA for treatment where you won’t have to do it again any time soon. I do know a few Max-Fax guys (maxillofacial surgeons) who’ll place implants under GA, thing is implant placement is pretty straightforward with proper planning, so there’s little chance of needing to do another GA to sort something out.

The current guidance for GAs in children is that there must be no carious teeth present at the end of the GA, so either all fillings are done first or else all carious teeth will be extracted at the GA. Again under KISS rules, you tend not to fill deciduous teeth (milk teeth) under GA.” (Gordon Laurie, BDS)

Some other disadvantages include:

  • GA can introduce a number of technical challenges for the dentist (having to get into awkward positions because the patient can’t be moved about much, breathing tube bringing the tongue forward and into the dentist’s way, working against a dead weight because the muscles are paralysed etc.).
  • Laboratory tests, chest x-rays and ECG may be required before having elective GA.
  • For some groups of medically compromised patients, GA is contraindicated for elective procedures.
  • You can’t eat for 6 hours beforehand.
  • On the day of the procedure you must have someone to collect you and look after you for 24 hours.
  • It’s expensive.

Under what circumstances can general anaesthesia be used?

Apart from facilitating dental treatment in children or patients with special needs, GA can be used in the following situations:

  • Conscious IV sedation works well for nearly all people with severe dental anxiety. But there will always be a few people for whom it doesn’t work, either because you find it impossible to cooperate even when sedated and/or because you have a very high tolerance to the drugs used for IV sedation. This can be more common if you’ve been taking similar drugs long-term for other mental health conditions.
  • A small number of people are unable to tolerate the idea of dental treatment of any sort unless they are rendered totally unconscious, regardless of the amount of pain they are suffering, and no amount of talking will make any difference. In this case, GA should be provided at least for the relief of pain and other emergency dental situations1. If it’s extractions that really terrify you, it may be possible to be put to sleep for the extractions and then have fillings etc. done under conscious sedation with local anaesthetic.
  • General anaesthetic is rarely needed for wisdom tooth removal, but may be recommended for especially difficult-to-remove ones. It can also be useful for certain other types of oral surgery.

How is general anaesthetic administered?

GA is usually started off (“induced”) by propofol IV in the hand or arm (for a description of how this works, click here. For children, some anaesthetists will induce with gas using a breathing mask – sevoflurane is quick enough to get them to sleep without too much fuss. In the old days, it used to be very unpleasant to induce with gas. The gas used back then (Halothane) smelled pretty bad and it was a fairly slow process, especially for adults. Sevoflurane, the agent used nowadays, doesn’t smell too bad and works very quickly.

Sevoflurane is also the agent used for maintaining general anaesthesia after induction, in both adults and kids.

What is it like? First-hand accounts of General Anaesthesia

“Once the I.V. was in the anaesthesiologist gave me something he said would make me feel “happy”. The nurse put a mask over my face that had oxygen in it for me to breathe. That felt good! Then he told me he’s going to put in the stuff to make me go sleep. I watched him put it all in to the I.V. line and then I don’t remember anything else. I don’t remember ‘falling’ asleep. I was awake one second, and sleeping the next. The very next thing I remember is waking up in the recovery room.”

“I sat bolt upright just as they were about to put the cannula in my arm for the anaesthetic and told them I couldn’t, but then I sort of managed to calm myself and asked them to knock me out asap (which they did) – I don’t actually even remember falling asleep which is weird! – The next thing I knew was the anaesthetist saying “Mark, it’s all over now”. “Is it?” I replied; then I was wheeled back to the day ward.”

“I’m 34 years old and had two impacted lower wisdom teeth and normal uppers. My oral surgeon was fantastic and suggested GA due to having all four removed. I was totally trepidacious, not sleeping the night before and pacing the waiting room just before the procedure. That said, this was the easiest and most painless surgery I’ve ever had. First they get you a little nitrous to calm you down, then they spray some sort of light freezing concoction on your arm before the IV….didn’t even feel the needle. 15 seconds later, you’re feeling fantastic. Next thing you know, you’re waking up. I had no pain whatsoever. I was alert soon after and able to leave.”

Will I be in pain when I wake up?

If post-op pain is expected, the normal practice is to inject a long acting local anaesthetic during the GA, so that when you wake up everything is nice and numb for a good few hours afterwards. This should give you time to take some painkillers and allow them to kick in. It’s much better to prevent pain than it is to try to deal with it once it has started.

Also, the anaesthetist can put in some opioids during the treatment to control post-op pain.

Will I wake up?

“I need to have impacted wisdom teeth taken out, and the oral surgeon strongly recommends GA – but I’m scared to death of being ‘put to sleep’ and not waking up!”

If GA has actually been recommended to you because the dentist or oral surgeon anticipates that the surgery will be too unpleasant otherwise, GA will make things much easier for you. Provided that a qualified anaesthetist oversees the procedure, the risk of death is extremely small. A recent review of the Death Rate of Dental Anaesthesia (2017) looked at 20 studies since 1955 and found 218 deaths out of 71,435,282 patients – that is one in 327,684. The deaths that did occur were mostly in patients whose health was compromised 2.

While of course each death that does occur is a tragedy for the individual and their family and friends, it really is an extremely unlikely event.

Is it possible to be put to sleep using gas instead of an IV? I have a fear of needles.

The induction of anaesthesia can be via either IV drugs or gasses (“inhalational induction”). Induction via IV drugs is preferred as it is quicker and safer.

With an inhalational induction, you gradually become more and more anaesthetised as you breathe in the gases. At the same time, your ability to keep your airway unobstructed diminishes and the anaesthetist will need to assist with this. In some people, this may be very difficult or impossible. IV inductions avoid this completely.

You can discuss the method of induction with your anaesthetist before your procedure. Regardless of the method, most anaesthetists will place an IV cannula once you are unconscious (in case they need to give further drugs during the procedure).

Further information

A Conscious Decision: A review of the use of general anaesthesia and conscious sedation in primary dental care (2000) (PDF)

Conscious sedation in the provision of dental care: report of an Expert Group on Sedation for Dentistry, Standing Dental Advisory Committee (2003) (PDF)

References

  1. N. M. Girdler, C. M. Hill, K. E. Wilson (2017). Conscious Sedation for Dentistry (p. 11). John Wiley & Sons Ltd.
  2. H. Mortazavi, M. Baharvand, and Y. Safi (2017). Death Rate of Dental Anaesthesia. Journal of Clinical and Diagnostic Research, 11(6): ZE07-ZE09.