TABLE 5.
Hemodynamic variables, spectral indexes of cardiac and vascular autonomic profile while supine and during 75° head-up tilt (HUT).
| Variables | Supine | HUT | Supine vs. HUT p-value |
| Hemodynamic variables | |||
| HR (beats/min) | 67 ± 8 | 74 ± 9 | 0.002a |
| SAP (mmHg) | 133 ± 15 | 97 ± 17 | <0.0011a |
| DAP (mmHg) | 84 ± 16 | 53 ± 11 | 0.002a |
| Respiratory rate (rpm) | 17 ± 3.3 | 17 ± 3.4 | 1.000a |
| Spectral analysis | |||
| RR (ms) | 913.7 ± 110.7 | 825.8 ± 103.2 | 0.001a |
| VARRR (ms2) | 395.0 ± 502.9 | 190.9 ± 286.8 | 0.060b |
| LFRR (ms2) | 52.5 ± 91.8 | 25.4 ± 58.0 | 0.080b |
| LFRR (n.u.) | 25.8 ± 20.6 | 26.9 ± 24.7 | 0.270b |
| HFRR (ms2) | 72.9 ± 87.2 | 23.1 ± 27.1 | 0.006b |
| HFRR (n.u.) | 68.4 ± 20.2 | 59.5 ± 25.2 | 0.230a |
| LF/HF | 0.6 ± 0.7 | 1.0 ± 1.6 | 0.420b |
| VARSAP (mmHg2) | 6.1 ± 5.6 | 20.8 ± 26.6 | 0.047b |
| LFSAP (mmHg2) | 1.0 ± 2.5 | 2.2 ± 2.8 | 0.047b |
| αLF (mm/mmHg) | 16.0 ± 12.2 | 3.9 ± 6.7 | 0.003b |
| Norepinephrine (ng/L) | 158.6 ± 65.3 | 248.3 ± 127.5 | 0.004a |
| Epinephrine (ng/L) | 25.7 ± 30.2 | 35.3 ± 33.2 | 0.005b |
aWithin group comparisons using paired t-test. bWithin group comparisons using Wilcoxon test. HR, heart rate; SAP, systolic arterial pressure; DAP, diastolic arterial pressure; RR, RR intervals; VAR, variance; LF, low frequency; HF, high frequency; LF, low frequency; HF, high frequency; n.u., normalized units.