|
| IVC CI | IVCmax | Comments |
|
Underestimate intravascular volume | | | |
Increased tidal volume (ventilated) | Increased? | No change? | |
Increased inspiratory effort moving probe “in & out” of field (diaphragmatic breathing) [18] | Increased | No change | Midaxillary or midclavicular line views [23]. Cross-sectional view [18] |
Increased inspiratory effort/deep breathing (sniff) [22, 28, 35] | Increased | No change | Large IVCmax with no collapse indicates being not hypovolemic |
Valsalva maneuver [19] | Increased | Decreased | Large IVCmax with no collapse indicates being not hypovolemic |
Intra-abdominal HTN [23, 36] | ? | Decreased | Large IVCmax with no collapse indicates being not hypovolemic. |
Off-center scan (cylinder tangent effect) [37] | Minimal changes | Decreased | Attempt to maximize IVC diameter. Cross-sectional view [18] |
Overestimate intravascular volume | | | |
Cardiac tamponade | Decreased | Increased | Preload dependent |
Severe valvular stenosis | Decreased | Increased | Preload dependent |
Massive pulmonary embolism [18] | Decreased? | Increased | Preload dependent |
Right ventricular myocardial infarction [38] | Decreased | Increased | Preload dependent, decreased venous return to LV |
Severe tricuspid regurgitation | Decreased | Increased | |
High PEEP [39] | Minimal change | Increased | No difference between PEEP 0 and 5 cm H20[39] |
Decreased tidal volume | Decreased | No change? | |
Decreased inspiratory effort/shallow breathing [22, 40] | Decreased | No change? | Highly collapsible IVC indicates being not hypervolemic |
|