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New strides in sleep pacemaker development

New strides in sleep pacemaker development

Monday, May 11, 2015

Just as a pacemaker can keep the heart beating steadily, so a similar device has now been created to keep breathing steady during sleep.

This device, designed for people who have obstructive sleep apnoea, generates pulses that help keep their airways open. It represents a possible paradigm shift in the treatment of moderate to severe obstructive sleep apnoea.

Men are more likely than women to suffer from this condition, which becomes more common as they gain weight and age.

The Australian Sleep Association estimates that some 10 per cent of middle-aged men and 5 per cent of middle-aged women in the general population have obstructive sleep apnoea.

When they sleep, their muscles relax and the soft tissue at the back of their throat collapses, blocking or reducing the flow of air.

This can last up to 60 seconds while they struggle to breathe. When the oxygen level in their blood falls, the brain wakes them just enough to open their airway.

They gasp or snort and then resume snoring. This cycle can repeat itself hundreds of times a night, and over time it can erode their health.

Obstructive sleep apnoea is associated with a spectrum of raised health risks: from persistent daily fatigue and irritability, to cancer, to sudden cardiac death.

It is not good for brain function either, and those who have a severe but untreated form of the condition are two to three times more likely to crash their car than the general population.

The new sleep device is implanted in the chest. While it is the latest possible treatment for this condition, it is still experimental and not suitable for everyone.

It was tested in the industry-sponsored STAR trial – Stimulation Therapy for Apnoea Reduction – which was conducted in 22 international centres.

According to the results, published in The New England Journal of Medicine, the device helped reduce breathing interruptions and raised blood oxygen levels in about two-thirds of patients with moderate to severe obstructive apnoea. These patients, mostly men in their 50s, previously had difficulty accepting or adhering to the mask that has become standard treatment for this condition.

This CPAP mask, which delivers continuous positive airway pressure, is unwieldy and many people don’t use it diligently because it is uncomfortable.

Being implanted, the device did not have such adherence issues. The study found it produced an improvement in quality of life and a reduction in sleepiness similar to that achieved with the mask.

The study was conducted on a highly selective group of patients. More than 900 were enrolled, but only 126 finally had the device implanted. There was no control group.

After using the device for a year, patients experienced fewer breathing pauses during sleep. On average, they went from 29 episodes an hour to nine.

Dangerous drops in blood oxygen levels also declined from 24 an hour to seven.

It is not known if diet, exercise or other factors contributed to these reductions.

After a year, two study participants had stopped using the device, while 86 per cent reported daily use.

Earlier in the study, the device caused serious problems for two patients who found it uncomfortable. They underwent a revision, during which the device was repositioned.

For reasons that are not understood, the condition worsened in about 20 patients participating in the study.

When it ended, the researchers went on to a second phase. This involved 46 of the patients who were doing well with the device.

They were divided into two groups. The first group continued with the device for a week, while the second had it turned off for a week.

Those in the first group experienced little change. Those in the second, however, rebounded. Their breathing pauses and drops in blood oxygen almost returned to their dangerous old levels.

Experts commented that this rebound was compelling evidence the device could produce good effects.

The device, yet to be approved for use in the United States, may only be useful for a subset of patients, such as those whose obstructions stem from airway collapse behind their tongues.

It also may not be useful for obese people who have a body mass index measuring over 32. The study excluded such people.

This implant could become a novel alternative to current treatment options, which include masks, dental devices, weight loss and medication.

Some who can’t use a mask or an oral appliance opt for various surgical procedures. These include advancing their jaw, a slight tongue reduction, removing tonsils or trimming a little off their soft palate.

This salvage surgery can be painful, and has varying degrees of efficacy.

Ron Grunstein, professor of sleep medicine at Sydney’s Woolcock Institute of Medical Research, says the STAR trial was conducted by highly regarded investigators, but the results need to be replicated.

It is crucial to follow patients over the long term, as their body weight may change and influence the effectiveness of the device.

If proved effective, he says, this device would play an important role in treating obstructive apnoea.

It would be expensive but should deliver results all night, every night, compared with a mask that a patient may or may not use.

Before it was implanted, other approaches should be exhausted.

The Australian Financial Review

BY JILL MARGO Health editor

Article can be found here

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