Obstructive Sleep Apnea
Polysomnography, OSA

Obstructive Sleep Apnea

Obstructive Sleep Apnea (OSA) & Sleep Study (Polysomnography)

What is OSA?

Obstructive sleep apnea (OSA) describes a medical condition that is characterized by intermittent episodes of absence of breathing (apnea) caused by complete obstruction of the upper airway passages during sleep. Narrowing of the air passages at the back of the throat occur in certain group of individuals including obese patients, patients with receding chins or certain facial features. Complete closure of these passages can occur during sleep as a result of further relaxation of the tissue at the back of the throat.

During these episodes of apnea, which last from 10-90 seconds, reduction of oxygen level in the body develops until the apnea is terminated by an arousal, which restores the airway patency. This cycle of events is repeated multiple times during sleep in individuals with OSA, resulting in fragmented sleep and daytime sleepiness. The severity can be as severe as 100 episodes of apnea in one hour.

How common is this condition?

 OSA is an under-recognized and under-diagnosed condition worldwide. It is estimated that OSA affects up to 25% of the adult population. A study showed that 93% of women and 82% of men with moderate to severe OSA are not diagnosed. 

What are the consequences of OSA?

Excessive daytime sleepiness is a major consequence of OSA.

It can result in:

  • Poor concentration and memory
  • Affect job and school performance
  • Affect relationships with spouses/partners
  • Poor quality of life
  • Increased risk of motor vehicle accidents

Oxygen starvation occurs during sleep and it increases the risk for:

  • High blood pressure (in patients with hypertension, the blood pressure may be difficult to control)
  • Heart failure and heart attacks
  • Heart rhythm abnormalities
  • Strokes
  • Increased lung pressures (pulmonary hypertension)
  • Death

OSA is also associated with increased total cholesterol and triglycerides, increased insulin resistance (and associated diabetes mellitus) and systemic inflammation.

When do we suspect OSA?

We suspect OSA in individuals with the following symptoms:

  • Excessive daytime sleepiness
  • Gasping and choking during sleep
  • Poor concentration at work or school
  • Behaviour problem in children
  • Loud habitual snoring
  • Hypertension especially poorly controlled and required multiple drug therapy
  • Obesity is the most important risk factor for OSA. OSA is present in about 45% of obese individuals. It was also found to be moderately prevalent (46%) among obese children.

How is OSA diagnosed?

In our clinic, we see patients who are suspected to have OSA based on symptoms reported by the patients, their spouses/partners or their parents. We also have patients who are referred to us by other specialists because of poorly controlled blood pressure, heart failure, arrthymia or obesity. A thorough physical examination will be done in the clinic. The diagnosis of OSA is further confirmed further by a sleep study (polysomnography) that is interpreted by our respiratory physician. A sleep study is necessary to confirm the diagnosis and to exclude other sleep disorders. It also shows the severity of the OSA.