Contrast enhanced ultrasound vs chest x-ray to determine correct central venous catheter position

We aimed to analyze the diagnostic accuracy of contrast enhanced ultrasonography (CEUS), compared with chest x-ray (CXR), in the detection of correct central venous line (CVL) placement. Our hypothesis was to verify whether CEUS could substitute CXR as a reference standard for correct placement of CVL or function as a triage test to limit the execution of CXR only for selected patients.

CEUS was carried out in 71 non consecutive patients to verify the correct positioning of a central venous line. Sensitivity, specificity, positive and negative predictive values, and likelihood ratios of CEUS compared to CXR, with their respective 95% confidence interval (CI), were calculated.

CXR identified 6 CVL misplacements (8,4%, CI 95% 3,2%-18%). Four of these were intravascular and 2 in the right atrium. CEUS identified only 3 misplacements, of which 1 was intravascular and 2 intracardiac. Using CXR as a reference standard, and considering intravascular and intracardiac malpositioning altogether, the sensitivity, specificity, and positive and negative likelihood ratio of CEUS were 33% (95% CI, 0%-71%), 98% (95% CI, 95%-100%), 21%, 7%, 0%, and 68%, respectively. The negative and positive predictive values were 94% (95% CI, 89%-100%) and 67% (95% CI, 13%-100%).

CEUS can't substitute CXR, or become a triage test in selected patients, in evaluating the correct tip position after CVL placement.