TY - JOUR T1 - Quantifying the ventilatory control contribution to sleep apnoea using polysomnography JF - European Respiratory Journal JO - Eur Respir J SP - 408 LP - 418 DO - 10.1183/09031936.00062914 VL - 45 IS - 2 AU - Philip I. Terrill AU - Bradley A. Edwards AU - Shamim Nemati AU - James P. Butler AU - Robert L. Owens AU - Danny J. Eckert AU - David P. White AU - Atul Malhotra AU - Andrew Wellman AU - Scott A. Sands Y1 - 2015/02/01 UR - http://erj.ersjournals.com/content/45/2/408.abstract N2 - Elevated loop gain, consequent to hypersensitive ventilatory control, is a primary nonanatomical cause of obstructive sleep apnoea (OSA) but it is not possible to quantify this in the clinic. Here we provide a novel method to estimate loop gain in OSA patients using routine clinical polysomnography alone. We use the concept that spontaneous ventilatory fluctuations due to apnoeas/hypopnoeas (disturbance) result in opposing changes in ventilatory drive (response) as determined by loop gain (response/disturbance). Fitting a simple ventilatory control model (including chemical and arousal contributions to ventilatory drive) to the ventilatory pattern of OSA reveals the underlying loop gain.Following mathematical-model validation, we critically tested our method in patients with OSA by comparison with a standard (continuous positive airway pressure (CPAP) drop method), and by assessing its ability to detect the known reduction in loop gain with oxygen and acetazolamide.Our method quantified loop gain from baseline polysomnography (correlation versus CPAP-estimated loop gain: n=28; r=0.63, p<0.001), detected the known reduction in loop gain with oxygen (n=11; mean±sem change in loop gain (ΔLG) −0.23±0.08, p=0.02) and acetazolamide (n=11; ΔLG −0.20±0.06, p=0.005), and predicted the OSA response to loop gain-lowering therapy.We validated a means to quantify the ventilatory control contribution to OSA pathogenesis using clinical polysomnography, enabling identification of likely responders to therapies targeting ventilatory control.Ventilatory instability can be measured by clinical polysomnography to guide nonanatomical sleep apnoea therapy http://ow.ly/AyXT3 ER -