Table 5.

Key measures of loop gain in OSA patients and controls

	Controls	OSA patients
Gold standard loop gain during sleep
Dynamic loop gain (pulses)	0.39 ± 0.04	0.57 ± 0.04
Plant (mmHg/(L/min))	1.04 ± 0.08	1.10 ± 0.07
Controller (L/min/mmHg)	0.41 ± 0.06	0.55 ± 0.06
Steady‐state loop gain (CPAP dial‐ups)	2.1 ± 0.5	3.4 ± 0.6
Breath‐hold predictors of loop gain
Ventilation after 20 s breath‐holds
First breath response (%eupnoea)a	204 ± 20	254 ± 32
Second breath response (%eupnoea)a	150 ± 13	197 ± 58
Maximal breath‐hold duration
All datab (s)	43.1 ± 4.7	31.8 ± 2.4
Spontaneous maximal breath‐holding duration (s)	38.0 ± 3.4	28.8 ± 2.7
Coached maximal breath‐holding duration (s)	53.1 ± 5.8	39.7 ± 3.8

Data are expressed as means ± SEM. ^aEupnoea is the baseline ventilation. ^bPrimary predictor.