Breathing condition | Site | ROC [95% CI] | Optimal threshold (%) | Sensitivity | Specificity |
---|
cIVC-ns | 1 | 0.76 [0.66; 0.86] |  > 35* | 0.68 | 0.78 |
 | 3 | 0.82 [0.74; 0.91] |  > 20* | 0.76 | 0.78 |
 | 4 | 0.85 [0.78; 0.94] |  > 33* | 0.66 | 0.92 |
 | 5 | 0.78 [0.68; 0.89] |  > 19* | 0.74 | 0.76 |
cIVC-st | 1 | 0.73 [0.62; 0.84] |  > 42* | 0.76 | 0.66 |
 | 3 | 0.80 [0.71; 0.91] |  > 49* | 0.76 | 0.85 |
 | 4 | 0.98 [0.97; 1] |  > 44* | 0.93 | 0.98 |
 | 5 | 0.83 [0.74; 0.92] |  > 25* | 0.87 | 0.67 |
- Measurements of inferior vena cava (IVC) diameters were carried out at five sites: at the IVC-atrium, then at 1 (site 1), 3 (site 3), 4 (site 4) and 5Â cm (site 5) caudal to the IVC-atrium junction. ROC area under the curve of receiver operating characteristics, CI confidence interval, cIVC-ns collapsibility index of the IVC in non-standardized breathing conditions, cIVC-st collapsibility index of IVC with standardized breathing manoeuvre. *Optimal threshold value to predict response to volume expansion