New formulas to predict the length of a peripherally inserted central catheter based on anteroposterior chest radiographs

Abstract

Purpose: To develop formulas that predict the optimal length of a peripherally inserted central catheter (PICC) from variables measured on anteroposterior (AP) chest radiography (CXR). Materials and methods: A total of 134 patients who underwent PICC insertion at the angiography suites were included. Clinical information such as patient height, weight, sex, age, cubital crease to inferior carina border length (CCL), and approach side were recorded. The following variables via measurement on AP-CXR were also collected: (1) distance from the T1 to T12 vertebra (DTV), (2) maximal horizontal thoracic diameter (MHTD), and (3) clavicle length (CL). Results: Significant correlations between CCL and the following variables were identified in linear regression analyses: approach side, height, weight, sex, DTV, MHTD, and CL. Multiple regression results motivated the following two formulas: (1) with height data, estimated CCL (cm) = 12.429 + 0.113 × Height + 0.377 × MHTD (if left side, add 2.933 cm, if female, subtract 0.723 cm); (2) without height data, estimated CCL = 19.409 + 0.424 × MHTD + 0.287 × CL + 0.203 × DTV (if left side, add 3.063 cm, if female, subtract 0.997 cm). Estimated final PICC length can be calculated as (Estimated CCL, cm) + 4.0 (distance from inferior carina border to about 2.0 vertebra body unit, cm) − (distance from set cubital crease to designated puncture point, cm). Conclusion: This study suggests new formulas to predict the appropriate PICC length for bedside insertion using previous AP-CXRs. With this formula, ideal positioning of the catheter’s tip can be achieved in the clinical practice, avoiding or minimalizing the exposed catheter out of skin. These formulas may be helpful for patients who cannot undergo intra-hospital transport due to hemodynamic instability or who are concerned about isolation precautions due to any infectious-related contamination.

Validation of the PICC length prediction formula based on anteroposterior chest radiographs for bedside ultrasound-guided placement

“…Based on the exclusion criteria of a previous study [ 10 ], bedside PICC placement with the length prediction formula was performed only for patients who did not have the following conditions: (1) patients without previous AP-CXR, (2) patients with unusual anatomic variations including persistent left-sided superior vena cava, severe unilateral lung volume loss, or scoliosis/kyphosis/compression fracture of the vertebrae, and (3) patients with difficulty in identifying the cubital crease due to redundant skin, burns, underweight, or severe edema.…”

“…After arriving at the patient’s side, first, the patient was placed in the supine position. The following steps are taken to establish the cubital crease, which was used as an anatomic landmark in the previous study [ 10 ]; the patient’s arm was abducted, and the elbow was flexed at 90°. Subsequently, the middle straight line among the skin folds was set as the cubital crease and marked.…”

“…One VBU was defined as the distance unit between the superior endplate of one vertebra to the superior endplate of the next, with the intervertebral disk included. Using the formula from the previous study [ 10 ], the CP + estimated PICC length (eCL) can be calculated. The formula was as follows: …”

“…In the “optimal” position, the tip of the catheter was located in the range of approximately 2.80 cm above and below the designated CAJ on AP-CXR. This range was set based on the 95% confidence level using the standard error reported in the previous study [ 10 ]. 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 (RA) without wedging into the atrial wall.…”

“…A previous study by Park et al demonstrated that the PICC length could be predicted using anteroposterior chest radiographs (AP-CXR), and related measurement factors and formulas were described [ 10 ]; however, the validation process was not included. The objective of this retrospective study was to validate the accuracy of the length prediction formula from the previous study [ 10 ] and determine whether it is technically feasible to perform PICC placement at the bedside using only ultrasound.…”