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. Author manuscript; available in PMC: 2023 Mar 26.
Published in final edited form as: Thorax. 2022 Jan 21;77(7):707–716. doi: 10.1136/thoraxjnl-2021-217756

Table 4.

Drive-Related Sleep Apnea Pathophysiology: Endotypes

Endotype All Subjects (N=50) Classic (N=20) Drive-Dependent (N=30)
 Collapsibility per Vpassive (%eupnea) 68[48,84] 65[35,80] 71[48,86]
 Muscle Effectiveness (%flow/drive) 24.7[1.0,38.5] 0.4[−0.2,23.7] 33.1[22.2,52.3]*
 Loop Gain 0.63[0.55,0.78] 0.62[0.54,0.72] 0.63[0.55,0.81]
 Arousal Threshold (%eupnea) 156[135,173] 171[155,198] 139[124,159]*

Endotypes were calculated from flow and drive data during non-REM sleep (arousal data removed, data are shown median[IQR]). Vpassive denotes the value of flow at eupneic drive. Muscle effectiveness is the slope of the plot between flow and drive. Loop gain represents the drive response to a reduction in flow (1 cycle per minute, i.e. LG1). The arousal threshold represents the level of drive preceding arousal from sleep. The greater muscle effectiveness in drive-dependent v. classic OSA provided for a greater level of ventilation without arousal (“Vactive”): 87[74,97] v. 69[36,85] %eupnea.

*

Denotes a significant difference (P<0.05) between drive-dependent v. classic groups.