Loop Gain Sleep Apnea
Methods for quantifying loop gain in osa using polysomnography have been developed that predict favorable responses to upper airway surgery. We compared the effect of oxygen on the apnea hypopnea index ahi in six obstructive sleep apnea patients with a relatively high loop gain lg and six with a low lg.
The factor by which the existing loop gain must be increased to produce instability is known in control parlance as the gain margin.
Loop gain sleep apnea. However these methods are. Arguably the strongest determinant of osa is a hypersensitive ventilatory control system or elevated loop gain during sleep. Unstable ventilatory chemoreflex control quantified as loop gain is recognized as one of four key pathophysiological traits that contribute to cause obstructive sleep apnea osa.
The init ial disturba nce is ove rcompensated while a low loop. The higher the loop gain the potentially more unstable the respiratory control system becomes. Loop gain measured noninvasively from polysomnography can be influenced by respiratory event scoring in obstructive sleep apnea osa according to study results published in the annals of the american thoracic society.
In the high lg group unstable ventilatory. As sleep related breathing disorders remain a major public health concern a greater understanding of the pathogenesis is required to develop and improve therapeutic options in the late 1970s it became known that ventilation during non rem sleep was critically dependent upon p co 2 levels in the early 1980s loop gain an engineering term used to define the sensitivity of a variable. We compared the effect of oxygen on the apnea hypopnea index ahi in 6 obstructive sleep apnea patients with a relatively high loop gain lg and 6 with a low lg.
Novel treatments aimed at reducing loop gain are being investigated with the intention that future osa treatment may be tailored to the individual s specific cause of apnea. Lg is a measure of ventilatory control stability. Loop gain in sleep apnea what is loop gain.
High loop gain promote s recurrent apnea as the response to. Loop gain and sleep disordered breathing. The presence of sleep reduces controller gain relative to wakefulness and more importantly upper airway tone particularly in rapid eye movement sleep rem see fig.
Linear control theory states that the loop gain must be increased to a value of unity before instability can occur 4 6. Lg is a measure of ventilatory control stability.
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