Obstructive sleep apnoea OSA


Obstructive sleep apnoea or OSA is a condition where an individual stops breathing when they are asleep. It is more common in the obese and so we are seeing it more frequently. Most patients also snore but not all patients who snore have OSA as snoring can also arise from nasal obstruction.


It is important to diagnose and treat OSA even in the absence of an anaesthetic. Patients with OSA often suffer from somnolence and poor concentration which can affect their performance at work. OSA is associated with diabetes, hypertension and a condition called cor pulmonale which can lead to heart failure.


OSA is of interest to anaesthetists because a patient with OSA who receives sedation or general anaesthesia is at risk of prolonged periods of apnoea when sleeping within the first 24 hours and this has in extreme cases led to death.


We use a screening test called STOPBANG to identify patients who may be at risk of OSA and the anaesthetic preassessment questionnaire that I use includes this score. STOPBANG asks eight questions with yes or no answers:

S              do you snore loudly?

T              do you feel tired or drowsy during the daytime?

O             has anyone witnessed you stopping breathing when you are asleep?

P             do you have hypertension?

B             what is your body mass index i.e. are you are overweight?

A             age. Are you over 50?

N             what is your neck size? For men it is over 17 inches and for women over 16 inches

G             gender. Men score as positive women as negative


If a patient scores 3 to 4 there is a moderate risk of OSA and I would want to evaluate the patient further. a score above 4 is highly indicative of OSA and we would consider that patient to be suffering from this problem unless proven otherwise. The definitive test is a sleep study where we ask the patient to sleep overnight connected to monitors and we record their breathing, movement and oxygen levels. If you think you suffer from OSA I strongly recommend you consider having a sleep study which we undertake at the Weymouth Street Hospital but can be obtained elsewhere. This is because OSA can be treated by a reduction in weight, use of a CPAP machine, or ENT intervention. Treating OSA can actually reverse diabetes, reverse hypertension and reduce the risk of heart disease.


When I assess patients who have a significant risk of OSA I always recommend a sleep study if their surgery is not urgent. If this demonstrates OSA or if we are unsure, we would monitor the patient overnight so that any episodes of apnoea can be picked up and dealt with. Patients with OSA cannot be a day case. If a patient is known to have OSA and is using a CPAP machine we asked them to bring it into hospital with them so that they can use it overnight