SINGAPORE, Aug 15 — He was overweight and ran the risk of sudden death during sleep but did not even know it at first.
For years, Zeng Yi went through his waking hours “half-awake” and “in a haze” of overwhelming sleepiness.
Last year, he was diagnosed with obstructive sleep apnoea, underwent surgery and lost almost 50kg to restore his health and breathe aright again.
Obstructive sleep apnoea is a common but potentially deadly sleep disorder that occurs when the upper airway is obstructed during sleep and causes recurrent pauses in breathing.
Ear, nose and throat surgeon Kenny Pang said that in severe forms of the disease, some patients may stop breathing as often as 200 to 300 times a night.
A sleep study, where a test recorded activity of the body during sleep, revealed that Zeng would stop breathing frequently during sleep, compromising his oxygen saturation level.
The 26-year-old Singaporean undergraduate said: “The results were pretty scary. Oxygen levels of under 90 per cent is already considered a serious problem, and mine was under 80 per cent. My life was on the line and I was not aware of it.”
Normal blood oxygen levels hover around 95 to 100 per cent.
Dr Pang, who treated Zeng, said that anything below 90 per cent is considered “dangerous” while a drop below 80 per cent is “very dangerous”.
More than just disrupt a good night’s rest, research shows that people with untreated obstructive sleep apnoea face a higher risk of sudden death during sleep and a host of other health issues such as heart attacks, stroke and hypertension.
Yet, the sleep disorder remains an under-recognised health problem.
Dr Pang, a consultant at Asia Sleep Centre, said: “Many cases (of sudden death due to obstructive sleep apnoea) are not reported because many patients with the sleep disorder are undiagnosed and unaware.
“That is why obstructive sleep apnoea is known as the silent killer.”
Singapore has one of the highest incidences of obstructive sleep apnoea in the world.
Dr Soh Rui Ya, a consultant with respiratory medicine at Sengkang General Hospital (SKH), said it is estimated that moderate to severe forms of the sleep disorder afflicted one in three people here.
This number is set to go up as obesity — the main risk factor for obstructive sleep apnoea — becomes more common, she said.
Dr Pang, who has conducted research on the sleep disorder, said that by comparison, the global incidence is around 12 to 15 per cent.
Severe cases such as Zeng make up around one in 10 cases.
When breathing stops during sleep
Obstructive sleep apnoea occurs when the upper airways are obstructed during sleep.
Most patients, Dr Pang said, have a narrow upper airway, which collapses and closes up at night during sleep.
This interrupts breathing, causing oxygen levels in the blood to plummet.
Studies show that patients with the sleep disorder have a six times higher chance of a heart attack and more than two times the risk of sudden death between midnight and 6am.
Dr Pang said that he has also seen patients with untreated sleep apnoea who have had strokes.
Some studies, such as one published in the medical journal BMJ Open Respiratory Research earlier this year, suggest that having obstructive sleep apnoea may raise the odds for severe Covid-19 and hospitalisation.
Dr Soh of SKH, which runs a sleep medicine clinic, said that people with obstructive sleep apnoea are not known to have a higher risk of getting Covid-19, but the risk factors for the sleep disorder — such as obesity — is associated with a higher risk of Covid-19 complications, including respiratory failure.
Patients may also have conditions such as hypertension, diabetes and cardiovascular diseases, which put them at a higher risk of Covid-19 complications.
Dr Soh said that a patient with obstructive sleep apnoea tends to be a person who is overweight, more commonly male and in the older age group. Common symptoms include loud snoring and choking or gasping during sleep.
“Patients may also suffer from marked daytime sleepiness, which can impair concentration and executive function. This can lead to higher risk of motor vehicle accidents and workplace accidents in at-risk occupations,” she said.
Small jaw increases risk
Even though obesity is a risk factor for obstructive sleep apnoea, not all patients are overweight.
Among Asians especially, the doctors pointed out that certain physical traits such as a small jaw and a receding chin increase the risk of a narrowed upper airway.
Dr Pang said that half of his patients are not obese but have a small jaw and chin.
Asians, in general, have smaller skeleton frames compared with Caucasians, he added.
“In the same vein, Asians have a smaller craniofacial skeleton, so there is narrower space in the oral cavity and upper jaw.
“If th soft tissues like tonsils, tongue and palate are overlarge and bulky, they would occupy a lot of space (in the oral cavity) and narrow the airway further.
“Plus, Singapore is an affluent country with rising obesity rates, hence the obstructive sleep apnoea situation is getting worse.”
No control over sleep and waking hours
In Zeng’s case, being overweight contributed to his breathing troubles at night. At his heaviest, he weighed around 130kg.
He decided to seek help after a family friend pointed out that it could be due a sleep disorder.
At the time, sleeping on his back was impossible. In that position, he could not breathe properly. This problem took a toll on his mental health.
He struggled to wake up in the morning. Despite setting his phone alarm on repeat and plugging in his earphones so that he would hear it ring, he would still sleep right through it.
“I had no control over waking up in the morning. If I wanted to study, I would be hit by a sudden wave of sleepiness.
“Initially, I thought I was just being lazy and unmotivated. It never occurred to me that it might be something else,” he said.
There are several treatment options for obstructive sleep apnoea.
For most patients, the first line of treatment is continuous positive airway pressure (CPAP) therapy, which uses a device to deliver gentle air pressure to the nose and back of the throat to keep the airway constantly open, Dr Soh said.
The device should always be used during sleep.
“By preventing the airway from collapsing, regular breathing is restored during sleep. CPAP therapy is safe, generally well-tolerated and highly effective,” she said.
However, the condition is that patients must use it every day for it to be effective and compliance can sometimes be a major hurdle.
For snoring and mild to moderate obstructive sleep apnoea, Dr Soh said that oral appliances are an alternative to CPAP therapy.
For instance, a dental appliance may be worn during sleep to re-position the jaw and tongue. This helps enlarge the upper airway and improve airflow during sleep.
There is also a range of surgical procedures designed to widen the upper airway and improve airflow during sleep.
Such procedures are recommended if first-line treatment fails and in selected patients who have abnormalities of the upper airway such as enlarged tonsils, which can be easily corrected, Dr Soh said.
Patients are also advised to do some modifications to their lifestyle such as avoiding drinking alcohol and taking sedatives at night. Some may benefit from sleeping on their sides to reduce snoring and choking episodes, Dr Soh added.
Dr Pang said that the estimated cost of surgery may range from S$10,000 to S$15,000 onwards, depending on the patient’s condition and type of surgery required.
A CPAP machine may cost around S$2,000 to S$4,000, depending on the model, while an oral appliance may cost around S$2,000 to S$3,000, he said.
Breathing normally again
For Zeng, his parents who are working professionals enabled him to undergo surgery in September last year to rectify his sleep problems.
“After learning that my oxygen level during sleep was under 80 per cent, I felt that my life was on the line and I had to do something about it quickly.
“I also did not want to worry over whether there is a (CPAP) machine near me when I sleep,” he said.
His surgery involved straightening the septum, which is the centre division of the nose.
The size of the sinus turbinate — bones in the nose that are covered with soft tissue lining — and the size of the enlarged adenoids — a patch of tissue that sits in the back of the nasal cavity — were reduced.
He also underwent a procedure known as expansion sphincter pharyngoplasty, developed by Dr Pang for obstructive sleep apnoea and snoring.
The surgical technique repositions the muscles on the sides of the throat to create a “tension pull” that brings the soft palate (roof of the mouth) forward, upward and to the sides to keep the upper airway open during sleep.
Although the recovery period after surgery was not easy, it marked a turning point for Zeng.
Immediately after the surgery, he was not able to eat normally because his throat felt sore. He took it as an opportunity to lose some weight.
With guidance from his doctor, Zeng changed his diet to avoid carbohydrates and sugary drinks and ate healthier food such as vegetables, fish and lean meat.
He also began exercising, starting with brisk walks and he now jogs regularly. He shed close to 50kg after the surgery.
Zeng said that his sleep quality has improved and he no longer he wakes up feeling exhausted.
“It’s like rediscovering breathing for the first time. Sometimes, when I take a deep breath now, I can still feel a kind of sharpness to the air that I’ve never experienced growing up,” he said.
“And because I wake up not feeling tired, I am able to get things done —that’s been pretty amazing.” — TODAY