Assessment of Baroreflex Sensitivity Using Time-Frequency Analysis during Postural Change and Hypercapnia

Table 1

Physiological parameters and baroreflex sensitivity estimates during normocapnia and hypercapnia with hypoxia in resting position.

Parameter	Normocapnia	Hypercapnia with hypoxia	Value
EtCO2 (mm Hg)	38 (34–40)	48 (45–50)	<10^−7
RR (breaths/min)	14 (12–17)	12 (11–14)	<10^−3
MAP (mm Hg)	88 (78–96)	98 (86–107)	<10^−6
PP (mm Hg)	67 (57–72)	71 (59–82)	0.002
HR (bpm)	73 (64–78)	74 (68–83)	<10^−3
LF BRS (ms/mm Hg)	9.2 (7.0–11.0)	8.1 (6.2–9.8)	0.02
HF BRS (ms/mm Hg)	10.7 (8.0–17.7)	10.6 (7.9–13.1)	ns

Values are presented as median (first quartile–third quartile). EtCO₂: mean end-tidal carbon dioxide level; RR: mean respiration rate; MAP: mean arterial blood pressure; PP: pulse pressure; HR: heart rate; LF BRS: baroreflex sensitivity in low-frequency range; HF BRS: baroreflex sensitivity in high-frequency range; ns: difference not statistically significant.