Figure 1.
CONSORT flow chart.
Figure 2.
Anatomical location of the two landmarks in the patient.
M1 is the central landmark (white arrow), determined by the apex of the triangle between the two heads of the sternocleidomastoid muscle. M2 is the alternative landmark (black arrow), determined by the inspection of respiratory jugular venodilation and direct internal jugular vein palpation.
Table 1.
Patient demographics and sonographic variables.
Figure 3.
Comparison of distances between M1 and M2 from the ultrasound-identified IJV.
Individual and median (interquartile range) distances between M1 and M2 from the ultrasound-identified IJV. For effective representation of the distance, the axes were inverted. The line in the middle box represents the median value and the lateral borders of the box represent interquartile ranges. Individual values are represented as dots (yellow dots in M1 and green dots in M2). M1, the central landmark; M2, the alternative landmark; IJV, internal jugular vein.
Figure 4.
ROC curve of the central venous pressure for the visible respiratory jugular venodilation.
Area under the curve is given inside the ROC curve. ROC curve, receiver operator characteristic curve.