Flow direction in the DV and HV during respiration
| Antegrade flow | Retrograde flow | High-frequency bidirectional flow | |
| DV | |||
| Inspiration (n=57) | 98 | 0 | 2 |
| Expiration (n=46) | 59 | 4 | 37 |
| Respiratory pause (n=41) | 81 | 0 | 19 |
| HV | |||
| Inspiration (n=61) | 82 | 0 | 18 |
| Expiration (n=72) | 25 | 13 | 62 |
| Respiratory pause (n=52) | 17 | 0 | 83 |
Data presented as %.
DV, ductus venosus; HV, hepatic vein.