Collapse of the inferior vena cava during respiration
| Inspiration (n=69) | Expiration (n=67) | Respiratory pause (n=32) | |
| Collapse | 40 (58) | 7 (10) | 26 (81) |
| Complete | 23 (58) | 5 (71) | 5 (19) |
| Incomplete | 17 (42) | 2 (29) | 21 (81) |
| No collapse | 29 (42) | 60 (90) | 6 (19) |
Data are presented as n (%).