Ultrasound for Localization of Central Venous Catheter: A Good Alternative to Chest X-Ray?

BACKGROUND: Chest radiography after central venous catheter (CVC) insertion is the main method of verifying the catheter location. Despite the widespread use of radiography for detecting catheter position, x-ray may not always be readily available, especially in the operating room.

OBJECTIVES: We aimed to compare contrast-enhanced ultrasonography (CEUS) and chest radiography for detecting the correct location of CVCs.

METHODS: One hundred sixteen consecutive patients with indications for CVC before cardiac surgery were enrolled in this observational study. After catheter insertion, CEUS was performed. Portable radiography was obtained postoperatively in the intensive care unit. Sensitivity, specificity, and predictive values were determined by comparing the ultrasonography results with radiographic findings as a reference standard.

RESULTS: Chest radiography revealed 16 CVC misplacements: two cases of intravascular and 14 cases of right atrium (RA) misplacement. CEUS detected 11 true catheter malpositionings in the RA, while it could not recognize seven catheter placements correctly. CEUS showed two false RA misplacements and five falsely correct CVC positions. A sensitivity of 98% and specificity of 69% were achieved for CEUS in detecting CVC misplacements. Positive and negative predictive values were 95% and 85%, respectively. The interrater agreement (kappa) between CEUS and radiography was 0.72 (P < 0.001).

CONCLUSIONS: Despite close concordance between ultrasonography and chest radiography, CEUS is not a suitable alternative for standard chest radiography in detecting CVC location; however, considering its high sensitivity and acceptable specificity in our study, its usefulness as a triage method for detecting CVC location on a real-time basis in the operating room cannot be ignored.