Research digest: Easy to digest updates on articles published in high impact journals.
Obstructive sleep apnoea (OSA) is a disorder characterised by repeated episodes of absent (apnoeic) or decreased (hypopnoeic) inspiratory airflow during sleep. The main mechanism behind this is that during sleep the pharyngeal muscle loses tone and so the throats airspace narrows. The tongue also loses tone and while lying back in bed, can fall into the remaining airspace pulled by gravity causing complete or partial obstructions. This invariably leads to snoring, and indeed many patients that do snore may have undiagnosed OSA!
These apnoeic and hypopnoeic events lead to recurrent drops in oxygen saturation and this predisposes the individual to an array of serious health risks including hypertension, heart attacks and strokes, decreased vigilance and road traffic accidents, and a seriously decreased quality of life with mood disorders. These patients have a disrupted sleep-wake cycle and are excessively sleepy during the day which is frustrating and upsetting to them.
A study stimulating both hypoglossal nerves in the treatment of OSA was recently performed and it assessed the safety and efficacy of the GenioTM system. The investigators assessed changes in the apnoea-hypopnoea index (AHI), an index used to indicate the severity of OSA, along with device-related serious adverse events, measures of sleepiness and other parameters. Twenty two patients completed the trial, which they were a part of for 6 months. Significant improvements were found in all of the measures, and the device had no problems; although, 3 patients (of the original 27 that were implanted) needed the device removed due to infection around the surgical site.
The study did have some limitations; the main being that, by design, it was an observational study and therefore did not have a control group. This is problematic as there is nothing to compare the positive results to and it could be that the improvements, however unlikely, would have happened with time anyway.
It remains to be seen if this therapy would make headways in changing the management of OSA but this trial does provide hope for patients with OSA who have failed CPAP, and remain untreated.
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