The difficult airway


One of the most important jobs of an anaesthetist is maintaining the patient’s airway. As we lose consciousness, the tongue falls back and the airway becomes obstructed. In addition, anaesthetic drugs such as narcotics can suppress breathing. In some anaesthetics we deliberately stop the breathing so that we can relax the muscles to allow surgery on the chest or the abdomen and to do this we need to pass an endotracheal tube into the top of the lungs to connect the patient to a ventilator.


In most cases this is completely routine and because we do it many times a day it is an extremely low risk procedure. A small number of patients may obstruct their airway such that it is difficult to maintain and we call this a difficult airway. Patients may also be difficult to intubate and this is again called a difficult airway although more accurately it should be called a difficult intubation.


The difficult airway is one of the commonest causes of anaesthetic complications. Throughout these blogs you will see references to national audit programmes which are very large audits looking at specific anaesthetic issues. NAP4 looked at the difficult airway and identified that it was one of the commonest causes of anaesthetic catastrophe.


All patients should be examined before a general anaesthetic and I make no exceptions. Physical examination allows us to identify and eliminate patients with a difficult airway with about 94% accuracy. This is very good news because by eliminating the difficult airway we can significantly reduce the risk of major complications under general anaesthesia.


For patients who have a difficult airway it is important to point out that this is not a disease. A minority of patients will be difficult due to other conditions such as obesity, abscesses in the jaw and abnormalities of bite. Elderly patients may have reduced movements of the neck as well as some deformity but in many difficult airway patients the problem is simply the relationship of different parts of the body.


Management of the difficult airway is too complex to describe in detail in this blog. The operation will determine whether intubation is required or whether other airway devices can be used. We now recognise airway specialists in anaesthesia and I am pleased to be considered as an airway specialist. I also only work in hospitals which have comprehensive equipment such as fibre-optic scopes which allow me to overcome these problems.


If you are a difficult airway your anaesthetist will hopefully identify the problem when he examines you and will be able to tell you how he is going to manage your anaesthetic. After your anaesthetic we always tell patients if they are a difficult airway and give them what is called an airway letter. This letter describes the problem, records what was done and offers advice to future anaesthetists. The airway letter might for example say that the patient should not have sedation or might say that the patient should only be anaesthetised by an airway expert. A copy of the letter is sent to the general practitioner and placed in the hospital notes but it is very important to keep the letter and show it to any anaesthetist before any future operation. Patients might also want to consider wearing a medic alert bracelet to warn non-anaesthetists should they be taken ill in the future