Table 3.
Rate of change (per minute and per mmHg LBNP) from baseline to presyncope for all physiological variables for the two trials
| Parameter | Rate of change (per min) | Rate of change (per mmHg) | ||||
|---|---|---|---|---|---|---|
| Trial 1 | Trial 2 | P-value | Trial 1 | Trial 2 | P-value | |
| HR (bpm) | 1.61 ± 0.15 | 1.56 ± 0.18 | 0.71 | 0.65 ± 0.06 | 0.63 ± 0.07 | 0.63 |
| MAP (mmHg) | −0.85 ± 0.09 | −0.73 ± 0.07 | 0.15 | −0.36 ± 0.04 | −0.30 ± 0.03 | 0.13 |
| SAP (mmHg) | −1.38 ± 0.09 | −1.22 ± 0.09 | 0.15 | −0.58 ± 0.04 | −0.50 ± 0.04 | 0.12 |
| DAP (mmHg) | −0.43 ± 0.07 | −0.34 ± 0.06 | 0.26 | −0.18 ± 0.03 | −0.14 ± 0.03 | 0.25 |
| SV (mL) | −2.08 ± 0.16 | −1.90 ± 0.11 | 0.19 | −0.86 ± 0.08 | −0.77 ± 0.05 | 0.15 |
| CO (L/min) | −0.05 ± 0.01 | −0.05 ± 0.004 | 0.23 | −0.02 ± 0.004 | −0.02 ± 0.002 | 0.20 |
| TPR (mmHg/L/min) | 0.03 ± 0.04 | 0.001 ± 0.02 | 0.43 | 0.01 ± 0.02 | 0.00002 ± 0.007 | 0.42 |
| etCO2 (mmHg) | −0.47 ± 0.06 | −0.43 ± 0.05 | 0.61 | −0.19 ± 0.03 | −0.17 ± 0.02 | 0.53 |
| MCAv (cm/s) | −0.72 ± 0.08 | −0.56 ± 0.08 | 0.12 | −0.30 ± 0.04 | −0.23 ± 0.04 | 0.12 |
| PCAv (cm/s) | −0.35 ± 0.08 | −0.35 ± 0.01 | 0.99 | −0.14 ± 0.04 | −0.14 ± 0.01 | 0.92 |
| ScO2 (%) | −0.16 ± 0.02 | −0.15 ± 0.02 | 0.64 | −0.07 ± 0.01 | 0.06 ± 0.01 | 0.53 |
Data are presented as means ± SE. HR, heart rate; MAP, mean arterial pressure; SV, stroke volume; CO, cardiac output; TPR, total peripheral resistance; etCO2, end tidal carbon dioxide; MCAv, middle cerebral artery velocity; PCAv, posterior cerebral artery velocity; ScO2, cerebral oxygen saturation. N = 18; N = 9 for PCA.