TABLE 3.

CARDIOVASCULAR AND RESPIRATORY VARIABLES MEASURED DURING REBREATHING BY SLEEP-DISORDERED BREATHING CATEGORY*

	Apnea–Hypopnea Index Category
	Total (n = 373)	<1 (n = 112)	1–4.9 (n = 100)	5–14.9 (n = 94)	15–29.9 (n = 25)	≥30 (n = 13)	CPAP users (n = 29)
CCR, cm/s/mm Hg	2.3 (1)	2.4 (0.9)	2.4 (1.1)	2.1 (0.9)	2.3 (0.8)	2 (0.8)	2.3 (1)
Change in MAP, mm Hg/mm Hg	1.2 (1)	1.3 (1)	1.2 (1)	1.1 (1)	1.2 (0.7)	0.8 (0.8)	1 (1)
Change in HR, beats/min/mm Hg	0.1 (0.6)	0.2 (0.6)	0.2 (0.5)	0.1 (0.6)	0.1 (0.4)	−0.2 (0.5)	−0.0 (0.5)
HCVR, L/min/mm Hg	1.7 (1.1)	1.7 (1)	1.6 (1)	1.8 (1)	1.3 (0.9)	1.2 (1)	2 (1.9)

Definition of abbreviations: CCR = cerebrovascular CO₂ responsiveness; CPAP = continuous positive airway pressure; HCVR = hypercapnic ventilatory response; HR = heart rate; MAP = mean arterial pressure.

^*Values shown are means (SD).