Computational and Mathematical Methods in Medicine

Research Article

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

Table 2

Physiological parameters and baroreflex sensitivity estimates during postural change between squatting and standing in normocapnia.


Parameter	Cycle 1			Cycle 2
Parameter	Squatting	Standing	Value	Squatting	Standing	Value

EtCO₂ (mm Hg)	39 (37–42)	38 (36–42)	0.005	39 (36–41)	38 (36–40)	0.002
RR (breaths/min)	15 (12–18)	14 (12–18)	ns	15 (12–18)	15 (11–17)	ns
MAP (mm Hg)	94 (86–108)	94 (88–101)	0.004	95 (87–108)	91 (84–101)	<10⁻⁴
PP (mm Hg)	74 (66–82)	73 (66–82)	ns	71 (67–76)	69 (65–80)	ns
HR (bmp)	76 (67–86)	82 (73–92)	0.003	70 (61–81)	81 (68–92)	<10⁻³
LF BRS (ms/mm Hg)	11.3 (6.6–19.7)	7.5 (4.9–11.0)	0.03	11.2 (6.3–17.0)	8.2 (5.4–12.1)	ns
HF BRS (ms/mm Hg)	12.1 (8.1–20.4)	7.0 (4.9–12.5)	0.001	14.9 (11.5–22.7)	8.2 (5.7–16.0)	0.002

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.