Obstructive Sleep Apnea (OSA) is a common condition in Singapore where the muscles and soft tissues in your throat relax, causing your airway to repeatedly narrow or collapse momentarily, affecting the usual smooth airflow. In turn, your diaphragm and chest muscles have to work extra hard to reopen the airway. You may rouse awake – sometimes hundreds of times throughout sleep – as you resume breathing; during which, you may experience gasping or jerking. This not only disrupts sleep, but also places stress on vital organs to sustain oxygen flow. As a result, patients with OSA often do not reach deep, restful phases of sleep, and are likely to feel tired during their waking hours.
Many people with OSA are not aware because the interruption is normally very brief, albeit excessive, that you will not remember waking up to catch your breath.
If you have OSA, you are likely to snore loudly and heavily as soon as you fall asleep. The snoring would then be silenced for a while as your breathing pauses. This silence is followed by a loud snort and gasp, as you attempt to breathe. This pattern then repeats itself throughout the night. People with OSA, however, are unlikely to be aware of their sleeping pattern and it is more often that a partner or family member notices it first.
The symptoms in children may be less clear but include: wetting the bed, choking or drooling or grinding their teeth in their sleep, perspiring a lot at night, unusual sleeping positions, restlessness during sleep, sluggishness or sleepiness, and learning and behavioural problems,
Although OSA itself does not cause any pain, it can lead to serious complications like hypertension or stroke. It is important that you consult a doctor if you exhibit a number of these symptoms.
In Singapore, overweight male individuals in the middle age group onwards are more likely to suffer from OSA. Cases are also more prevalent in the Chinese population – likely due to certain bone features that are more common within that ethnic group – followed by the Malays and Indians.
Here, 15% of the population experience sleep apnoea, and the prevalence may have increased with the rise in other health-related trends, such as physical inactivity and obesity. The prevalence of OSA is also expected to rise in tandem with the ageing of our population, which is also a factor of OSA.
The initial assessment of OSA involves a history and physical examination. You will be asked about daytime fatigue, sleep habits and quality of sleep to identify any noticeable symptoms. You will also be checked for physical telltale signs.
After the initial assessment, patients will usually be warded for 1-2 nights for a sleep study that is performed as a polysomnography (PSG) using multiple channels to monitor several physiologic variables. Any abnormal patterns of physiologic variables may point to sleep-disordered breathing. Sleep studies can also be conducted from the comfort of your home albeit with a more limited range of monitoring.
The PSG will measure the activity of different organ systems while you are asleep. It usually involves the combination of an electroencephalogram (EEG), electrooculogram (EOM), electromyography (EMG), electrocardiogram (ECG), and pulse oximetry test. Together, these tools monitor your brain waves, eye movement, muscle activity, heart rate and rhythm, and blood oxygen levels, respectively.
As you reach deep sleep, you should experience decreased muscle tone and paralysis (indicated by our brain waves and eye movement). Along with decreased muscle tone, our muscles should also relax. Our heart rate and rhythm should slow and oxygen levels lower.
The treatment plan will depend on the analysis of the sleep study, as well as the severity of symptoms and patient’s age, BMI, and physical features. In treating OSA, the goal is to make sure airflow is sustained during sleep.
Continuous Positive Airway Pressure (CPAP) therapy is the first line of treatment. CPAP therapy delivers positive airflow to keep the airway open at night, through a face mask patients are required to wear throughout sleep. While it is known to be highly effective, it may not work for patients with mild OSA. Instead, an oral appliance may be used to treat mild OSA.
Where CPAP therapy is not effective, Bilevel Positive Airway Pressure (BPAP) machines may be used. BPAP machines are non-invasive ventilators that deliver pressure in response to you inhaling and exhaling, to facilitate breathing.
Patients may also undergo positional therapy to learn to sleep on their side, instead of on their back which can make OSA worse for some patients.
For obesed patients with OSA, weight loss has been shown to alleviate the severity of OSA. Losing weight, if recommended, could also improve quality of life and reduce daytime fatigue.
In cases where none of these methods work, you may consider surgery. Surgery may be most effective for patients whose OSA can be surgically corrected as in the case of an obstructing lesion in the airway. While surgical treatment can be effective, it does not completely eliminate OSA.