Fig 1.
Anatomic landmarks and parameters on anteroposterior chest radiographs.
(A) Designation of the cubital crease and skin puncture point. (B) Parameters measured on anteroposterior chest radiographs: (1) distance from the superior endplate of the T1 vertebra to the inferior endplate of the T12 vertebra (distance of thoracic vertebrae, DTV), (2) maximal distance between the inner edges of the ribs (maximal horizontal thoracic diameter, MHTD), (3) length between the midpoints of proximal and distal ends of the ipsilateral clavicle (clavicle length, CL).
Fig 2.
Schematic illustration of parameters.
Calculation of the distance from the cubital crease to the puncture point (CP) + estimated PICC length (eCL) using the formula of Park et al. (CP + eCL, cm) = 19.409 + 0.424 × (MHTD, maximal horizontal thoracic diameter) + 0.287 × (CL, clavicle length) + 0.203 × (DTV, distance of thoracic vertebrae) + (2VBUs, two vertebral body units below the carina inferior border). If approaching from the left, add 3.063 cm; if female, subtract 0.997 cm. Catheters were pretrimmed according to the eCL prior to the procedure.
Fig 3.
Procedure site of the PICC insertion at the bedside under ultrasound guidance.
(A) Disposable drapes with two holes were used to allow the ultrasound probe to access both the puncture site of the upper arm and the neck and subclavian areas. (B) An ultrasonic probe was placed in the subclavian area to ensure that the guidewire was not twisted in the axillary vein and was advanced smoothly as a single strand. Additionally, the ipsilateral internal jugular vein was assessed to ensure that the guidewire was not inserted in the cranial direction.
Fig 4.
Validation success of catheter length prediction.
The results were classified as optimal or suboptimal. In the "optimal" position, the tip of the catheter was located in the range of approximately 2.80 cm above and below the designated cavoatrial junction on anteroposterior chest radiographs. In the "suboptimal" position, the catheter tip was positioned in the superior vena cava (SVC) zone (below the designated upper margin of the SVC) or right atrium without wedging into the atrial wall.
Table 1.
Patient characteristics and variables measured on AP-CXR.
Table 2.
Technical success and validation success of catheter length prediction.