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Won - Figure 14

Mechanism: High vs Low Loop Gain

FIG. 14:  Based on the definition in the previous Figure, a high loop gain is an unstable state, as shown in this Figure (Panel B).[11]  In this case, there may be an exaggerated response (a hyperpnea) to an apneic disturbance that reaches the point of an apneic threshold, which induces another CSA, and so forth, resulting in cyclical events. 

In contrast, a low loop gain (Figure, Panel A) is a more stable state.  An example of a physiologic low-loop gain state is sleep itself, or more specifically REM sleep.  During REM sleep, a larger range of O2 and CO2 changes is tolerated, with minimal ventilatory response.  The result may be prolonged events or significant desaturations during obstructive apneas, but periodic or CSR rarely occurs during REM sleep.  

Won C. Chest 2016;00.

References

[11]

White DP. Pathogenesis of obstructive and central sleep apnea. Am J Respir Crit Care Med. 2005;172:1363–70.