Sleep App Near?

“NHS begins treating sleep apnoea with pioneering chest implant” - the headline caught my attention as I perused the Guardian website whilst eating my porridge. A techy solution for a common problem, now on the NHS and raising the tantalising prospect of being able to switch off someone’s snoring, perhaps via a smartphone app? Perfect clickbait, for me at least. Guys and St Thomas’s health trust is now offering hypoglossal nerve stimulation (HGNS) implants for Obstructive Sleep Apnoea and have so far carried out the procedure on 3 patients. But what is HGNS? How does it work? Will it benefit my patients? And is there an app?

Obstructive Sleep Apnoea (OSA) is a significant problem affecting 3% of women, 10% men aged 30-49 years old and up to 17% of men aged 50-70 years old (although these figures may be very conservative). Risk factors include obesity, neck circumference >40.6cm, smoking, alcohol and sleeping supine. There are important potential complications, including motor vehicle accidents, impaired glucose metabolism and increased risk of cardiovascular disease, with a rise in mortality as a result. Lifestyle changes can have a positive effect, but the mainstay of treatment is Continuous Positive Airways Pressure (CPAP), which as its name implies, delivers constant and steady air pressure via a hose and mask to keep the airways open. Not everyone gets on with CPAP, which is why alternatives are being sought. Oral mandibular devices may help in mild OSA and surgery may be effective, mainly if there are discrete anatomical lesions causing the problem. HGNS works by causing the tongue muscles to contract in time with the patient’s breathing, moving the tongue forward and keeping the airway clear. It does this via a small pacemaker-sized device inserted into the chest wall and a cable that is tunnelled under the skin and connected to the hypoglossal nerve. This is then switched on via a handheld controller by the patient before sleep and off on waking. 

Does HGNS work?

An evaluation of HGNS was published in JAMA Otolarygology – Head and Neck Surgery in 2019. The conclusion was that HGNS appeared to lead to a significant improvement in objective measures of OSA severity and subjective measures of daytime sleepiness and sleep-related quality of life. The study was restricted to patients who were unable to tolerate CPAP with moderate to severe OSA. Younger and heavier adults tended to see less improvement. NICE produced guidance in 2017 and commented that there was a lack of evidence for the effectiveness or safety of the procedure at the time. The guidance was due a review in 2020 but that has not yet appeared. 

Which patients can benefit from HGNS?

According to the Sleep Foundation, HGNS is currently being studied as a alternative to CPAP for children and adolescents with Downs Syndrome – 60% of whom have OSA and struggle with CPAP. People with failed CPAP can be considered, but it should be borne in mind that patients with a BMI of more than 32 are less likely to find the treatment successful. Guy’s and St Thomas’ Sleep Disorder centre will accept referrals from GPs via the NHS e-Referral Service for consideration of HGNS.

Is there an App?

Sadly, I was unable to find any information about a smartphone app that would allow someone’s snoring to be switched off, much to the disappointment of Mrs Ward.