From: Use of ultrasound-measured internal jugular vein collapsibility index to determine static intracardiac pressures in patients with presumed pulmonary hypertension
Ultrasound measurements
Mean (SD)
IJ at rest (cm)
1.17 (0.41)
IJ at inspiratory breath hold (cm)
1.39 (0.44)
IJ with external compression (cm)
0.73 (0.43)
Respiratory CI (ratio)
0.16 (0.13)
Compression CI (ratio)
0.40 (0.24)