What is Sleep apnoea?
Obstructive sleep apnoea (OSA) is much more common than central sleep apnoea.
Apnoea simply means that airflow is not getting into the respiratory tract for 10 seconds or longer.
Obstructive Sleep apnoea syndrome (OSAS) is recurrent episodes of OSA with symptoms of disrupted sleep.
So most people mean Obstructive sleep apnoea syndrome when referring to sleep apnoea & OSAS is therefore the focus of this article. We are referring here to adult OSA which managed by The GP in collaboration with the sleep clinic.
Childhood OSA is a common kid’s health issue caused by large tonsils & adenoids.
What causes sleep apnoea?
Sleep apnoea can be thought of as breathing in “against” an obstructed upper airway during sleep.
The upper airway obstructs because the muscles of the upper airway relax during sleep, and
- The lower part of the jaw (mandible) may be positioned more backwards than normal
- The side of the upper airway may be narrowed by fat pads
When breathing “in” against an obstructed upper airway, the nervous system kicks in to increase the tone in the relaxed upper airway muscle. The obstruction is thereby relieved. However, there will be some arousal during this time that will disrupt sleep quality.
There is thought to be a genetic component to OSA.
What are the Symptoms of Sleep Apnoea?
The symptoms of OSAS may be any of
- Excessive sleepiness in the day time despite getting enough time asleep (Epworth Sleepiness Score of 11 or more)
- Recurrent episodes of apnoeas that are witnessed
- Episodes of night-time gasping or choking or shortness of breath
- An event such as falling asleep at the wheel of a car
- Headaches in the early morning
- Dry mouth on waking
Snoring is common (not always) in people with OSAS.
This is The Polysomnograph from the Full Sleep Study
How is Sleep apnoea diagnosed?
These two tests are commonly used to diagnose sleep apnoea
- Full sleep studies: The most commonly used test in Australia – widely available and medicare rebate is available.
- Measuring Oxygen concentration in the blood overnight: This is a very simple screening test using the clip that goes over a finger, and is done at home. The problem is that the test is nothing like as accurate as a full sleep study – but better than no test. When this test is positive, the person should have full sleep studies.
The full sleep studies are carried out in a sleep clinic. The sleep rooms are setup in a way that will make you feel relaxed. People often report that they sleep better than they expected to.
Only full sleep studies will indicate whether the Sleep Apnoea is mild, moderate or severe – and this information is important. The sleep study will give a breakdown of the number of episodes of hour of both apnoea and Partial apnoea (hypoapnoea), what position they occur in (lying on the back for example), airflow in the mouth and nasal passage, the oxygen saturations, chest wall movements and brain sleep activity (EEG brainwaves).
Does Sleep apnoea need treatment?
Sleep apnoea usually needs treatment for one of two reasons
- The sleep apnoea is moderate or severe – because of the associated risks of sleep apnoea (high blood pressure etc.)
- The symptoms are severe enough to warrant treatment – to improve quality of life (this may include mild sleep apnoea). So people with even mild sleep apnoea may benefit from treatment if the treatment makes them feel better.
There are two crucial pieces of information you’ll need to decide on treatment options:
- From the Sleep Study (Polysomnograph): is the sleep apnoea mild, moderate or severe?
- From your symptoms: How much are you affected from the “Epworth Sleepiness Score”
10% of the population have an Epworth Sleepiness Score of 11 or more. The higher the score, the more significant your symptoms.
What can I do myself to treat the Sleep Apnoea?
Weight loss in obese patients may be very helpful.
An analysis of nine studies¹ found that an average reduction of the body mass index of 4.8 resulted in a 52% reduction in apnoeic episodes. That’s a weight loss of around 11-14 Kg.
What is CPAP?
This is a CPAP facemask – there are lots of different ones
CPAP is continuous positive airways pressure. The mask forms a seal around the mouth and/or nose. The quiet motor unit pushes out filtered air into the mask. The pressure in the upper airway is thereby positive throughout the breathing cycle. The positive pressure prevents the collapse of the upper airway. In effect, the upper airway is splinted open.
CPAP was regarded in a BMJ 2014 review as “The treatment of choice for symptomatic moderate or severe OSAS”
It takes a few days to get used to the facemask.
It’s not for everyone as some people find they don’t get onwith it despite trying out different types of mask.
What other treatments are there for sleep apnoea?
There are other non-surgical treatments for milder OSA that are gaining a role.
Mandibular advancement splints
This devices moves the bottom jaw (mandible) forward and can help those with mild or moderate OSA.
The device helps the most:
- When the body mass index is not high
- In younger people
- In women.
- Face shape has a slightly receding jaw
- When sleep apnoea is improved by lying on the side
The device is unlikely to help enough when there is severe sleep apnoea. The device is less likely to help in older or obese people.
There are different types of manibular advancement device:
- ‘Boil and Bite’ devices for under $100.
- Semi-Tailored devices costing a little over $200. You take a dental impression and this is sent off to make the device.
- Tailored devices costing around $2000. These are made by sleep specialists or dentists.
It’s reasonable to try a Semi-Tailored device first as suggested by The TOMADO trial.
The mandibular advancement device is of course silent, portable, and unobtrusive.
These are disposable Provent Nasal Valves
Provent – Also a useful option for the milder OSA. These are disposable small devices that you attach to the front of your nose with adhesive. They have a one-way valve that means you can breathe in through your nose but the valve restricts airflow out – thereby increasing pressure of the upper airway.
What about surgery for Sleep Apnoea?
It’s quite common to see people who have tried CPAP and havn’t gone any further. The problem is that untreated moderate or severe sleep apnoea has long term issues for health – quality of life, mental performance, driving risks, high blood pressure and cardiovascular risks.
Multiple studies of CPAP – also OSA surgery – have now shown improvements in such outcomes.
There is quite a high failure rate of CPAP for a variety of reasons eg. not well tolerated, masks not fitting. Under these circumstances, it may be worth considering an assessment for surgery. There are well over 10 different types of surgery for OSA. So this is a complex area. The point to make is that there may well be alternatives to CPAP. Those with moderate or severe OSA should really not “give up” at the stage of perhaps failing CPAP therapy. It’s well worth exploring surgical options with a specialist OSA ENT Surgeon.
When do I not need treatment for Sleep apnoea?
- Mild Sleep apnoea without Symptoms (a low Epworth Sleepiness Score)
- When episodes of sleep apnoea have been reported by my partner that only occur lying on my back after consuming alcohol
What else should I know about Obstructive Sleep Apnoea?
- There is an association between the more severe OSAS, High Blood Pressure & Vascular Risk – itt’s not clear whether this is causation or just an association
- Around 1 in 5 people with Type 2 Diabetes have OSAS
- Starting Testosterone Replacement Therapy (TRT) may exacerbate sleep apnoea
- CPAP reduces blood pressuring during sleep and during the day – by around 1.5mm or so (not much but measurable)
- It’s not proven that CPAP reduces Vascular events though provisional evidence does support that this is likely to be the case
- There are important driving regulations regarding sleep apnoea – discuss with your doctor or sleep clinic.
- The sleep study may indicate that apnoea or hypoapnoea occurs only when lying on your back – in which case you can try wearing a positional sleep device (eg. a night shift) to encourage you to lie on your side
1: Sleep Breath 2013; Anandam A et al; 2013 Mar;17(1):227-34