Table 5. Effect of HPV on regional flow, V/Q matching, and oxygenation.
Model simulations were performed with uniform vasoconstriction (UVC), and with and without regulation by HPV. All simulations used a fixed 25 mmHg arterial-venous pressure drop. The top block summarizes how HPV and uniform vasoconstriction (UVC) affects the total flow through the organ, and the variability of blood flow, V/Q ratio by the Coefficient of Variation (CV = μ/σ). The bottom block summarizes how HPV impacts the oxygenation in terms of the total alveolar-capillary oxygen mass flux, oxygen mass flux CV, oxygen mass flux normalized to total oxygen flux, venous oxygen tension, and venous oxyhemoglobin saturation.
| Network A | Network B | Network C | |||||||
|---|---|---|---|---|---|---|---|---|---|
| w/o HPV | w/ HPV | UVC | w/o HPV | w/ HPV | UVC | w/o HPV | w/ HPV | UVC | |
| Total Flow (ml/s) | 1.10 | 0.38 | 0.26 | 2.32 | 0.62 | 0.60 | 1.77 | 1.07 | 0.46 |
| Total Resistance (mmHg s/ml) | 28.03 | 80.13 | 117.64 | 13.32 | 49.45 | 51.16 | 17.47 | 28.78 | 67.13 |
| Flow CV | 2.47 | 1.28 | 2.42 | 2.35 | 1.42 | 2.44 | 2.09 | 1.08 | 2.35 |
| V/Q CV | 3.42 | 1.24 | 2.45 | 1.78 | 1.65 | 2.75 | 3.39 | 1.36 | 1.65 |
| Total Alv-cap O2 flux (mmol/s) | 4.6 | 11.6 | 5.0 | 29.7 | 70.1 | 28.8 | 3.8 | 5.6 | 2.3 |
| Alv-cap O2 flux CV | 0.30 | 0.25 | 0.26 | 0.25 | 0.27 | 0.28 | 0.52 | 0.48 | 0.58 |
| O2 flux CV / Total O2 flux (s/mol) | 66.19 | 22.14 | 51.9 | 8.37 | 3.84 | 9.71 | 139.19 | 87.23 | 256.33 |
| Venous O2 (mmHg) | 81.26 | 100.20 | 78.03 | 56.66 | 96.45 | 61.72 | 54.79 | 74.63 | 60.57 |
| Venous O2 (%) | 0.94 | 0.97 | 0.93 | 0.85 | 0.96 | 0.87 | 0.84 | 0.92 | 0.87 |