Canadian Anesthesiologists' Society

OSAHS: Obstuctive sleep apnea/hypopnea syndrome

What does it mean?

When you go to sleep the muscles in your upper airway relax. In people without OSAHS (more commonly called "sleep apnea") this is of no concern. Those suffering from sleep apnea have narrow upper airways and/or the muscles keeping the airway open do not work normally. This results in an airway that collapses during sleep, thereby preventing air flow. The result of this is apnea (no breathing) or hypopnea (less than normal breathing). Your brain stills sends signals to your diaphragm and you still make efforts to breathe.

How common is OSA ?

1 in 25 men and 1 in 50 women have been diagnosed with OSA severe enough to affect long-term health. However it is estimated that 70-80% of patients living with OSA remain undiagnosed.

I don’t know if I have sleep apnea. What are the symptoms?

Symptoms can either be due to air flow problems (see above) or due to lack of sleep as result of a poor quality of sleep.

Symptoms of airway obstruction are loud (can be heard through closed doors) and frequent snoring. Your sleeping partner may also witness short spells of apnea. You or your sleeping partner may recall choking when wakon up or frequently waking up for a very short periods (called ‘arousals’)

The result of sleep apnea is that you are not rested, even you slept for eight hours as the quality of your sleep is very poor. Thus you may wake up feeling fatigued and sleepy. If you easily fall asleep in front of the TV, in the subway, reading a book etc. you may be suffering from sleep apnea.

Are there physical features that makes this more likely?

Those who are obese (BMI > 35) and have a thick neck ((>17 inches in males and >16 inches in females) are more likely to have sleep apnea. Sleep apnea is also more common in middle-aged males. Children with large tonsils and abnormalities of the skull and face are also at increased risk.

I suspect I may have sleep apnea. How do I confirm or rule this out ?

Ask your family physician to refer you for a sleep study. This is widely available throughout Canada. If you have the diagnosis, be sure to let your anesthesiologist know!

There is no time for a sleep study before my surgery!

When a sleep study cannot be performed before surgery, your anesthetist may treat you as if you have the condition if you fit the typical profile.

Why is it important for my anesthesiologists to know if I have sleep apnea ?

‘Going under’ and ‘staying under’ anesthesia, requires a combination of medications. Most of them can still affect your breathing even after you have ‘woken up’ after your surgery. Someone without OSA copes well with these lingering effects, but those with OSA may experience a significant worsening in their symptoms in the first day or two after their operation.

The overall risk of a significant event depends on the severity of your OSA and the type of anesthesia you have received and the surgery itself.

I am already using a CPAP machine for sleep apnea. Do I need to take it to the hospital?

It is used to keep your airway open while asleep. If you have been prescribed CPAP, you should continue using it on a regular basis, and bring it to the hospital when you have any type of surgery.

Will having sleep apnea change my anesthetic?

The anesthetic you will get is tailored to your specific surgery and comprehensive health assessment. Having sleep apnea is one of the important factors to be considered. Having a regional anesthesia (hyperlink to section on regional anesthesia) only (without any intravenous medications that affect your level of consciousness) is the best option, but may not be possible due to various other reasons.

Key references:

Dr. Girish P. Joshi The patient with sleep apnea syndrome for ambulatory surgery. ASA refresher course 2009.

ASA Practice guidelines for patients with OSA: Anesthesiology 2006; 104: 1081-93.

Written by:
Dr Mandy Lam, MD (Resident Physician) and Dr Cindy Wang,  MD (Resident Physician)

Reviewed by:
Dr. Martin van der Vyver,  MBChB FRCPC (Specialist Anesthetist)

Date created:
October 22, 2010 



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