Table 3.

Accuracy with which the collapsibility index of the inferior vena cava (cIVC) predicts fluid responsiveness

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 5 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