Table 2.
Hemodynamic changes to an orthostatic stress test on Earth and Mars after a long-duration spaceflight.
| Setting: | Long | Long | Long | Long | Long | Long | ||
|---|---|---|---|---|---|---|---|---|
| Earth | Earth | Earth | Earth | Mars | Mars | |||
| No FL | No FL | FL + | FL + | No FL | No FL | |||
| Simulation | Literature | Simulation | Literature | Simulation | Literature | |||
| Hemodynamic variable | standing-supine | standing-supine | Standing-supine | standing-supine [limits] | Ratio 1 | standing-supine | standing-supine [limits] | Ratio 2 |
| SAP (mmHg) | −11 (−11%) | n.a. | −14 (−13%) | −42.4 to −5 | 1.2 | −4 (−4%) | n.a. | 0.3 |
| DAP (mmHg) | −2 (−2%) | n.a. | 0 (0%) | −21.8 to 0 | 0 | 1 (+1%) | n.a. | 0 |
| MAP (mmHg) | −6 (−7%) | n.a. | −7 (−8%) | −28.6 to −5.7 | 1.1 | −1 (−1%) | n.a. | 0.1 |
| CVP (mmHg) | −3 (−153%) | n.a. | −3 (−124%) | n.a. | 0.8 | −2.0 (−92%) | n.a. | 0.6 |
| HR (bpm) | 39 (+41%) | n.a. | 29 (+33%) | 21.6 to 45 | 0.8 | 7 (+7%) | n.a. | 0.2 |
| CO (l/min) | −1.1 (−28%) | n.a. | −1.5 (−34%) | −6.6 to −1.4 | 1.2 | −0.4 (−10%) | n.a. | 0.3 |
| SV (ml) | −20 (−49%) | n.a. | −23 (−49%) | −63.7 to −31.9 | 1 | −6 (−16%) | n.a. | 0.3 |
| SVR (mmHg*l-1*min) | 7 (+33%) | n.a. | 7 (+34%) | 9.3 to 19.7 | 1 | 3 (+12%) | n.a. | 0.4 |
Values for supine were taken at t = −50 s. and for standing at t = 100 s of the simulation. All values are differences between standing and supines, except those with brackets -they indicate the percentual changes- and the ratios. Ratio 1 shows the effect of fluid loading by dividing the percentual change of a stand test with by one without fluid loading. Ratio 2 shows the effect of performing a stand test on Mars versus on Earth by dividing the percentual change caused by a stand test performed on Mars by the same stand test when returning to Earth after a long-duration spaceflight (without fluid loading).
SAP systolic arterial pressure, DAP diastolic arterial pressure, MAP mean arterial pressure, CVP central venous pressure, HR heart rate, CO cardiac output, SV stroke volume, SVR systemic vascular resistance, FL fluid loading, n.a. not available.