Central vascular catheter placement evaluation using saline flush and bedside echocardiography.

OBJECTIVES: Central venous catheter (CVC) placement is a common procedure in critical care management. The authors set out to determine echocardiographic features during a saline flush of any type of CVC. The hypothesis was that the presence of a rapid saline swirl in the right atrium on bedside echocardiography would confirm correct placement of the CVC tip, similar to the accuracy of the postplacement chest radiograph (CXR).
METHODS: This was a prospective convenience sample of emergency department (ED) and intensive care unit (ICU) patients who had CVCs placed. Investigators used subcostal or apical four-chamber echocardiography windows to evaluate the onset and appearance of turbulent flow in the right atrium when the distal port of the CVC was flushed with 10 mL of saline. Onset was rated as "immediate" (within 2 seconds), "delayed" (2 to 6 seconds), or "absent" (did not appear within 6 seconds). Appearance was rated as "prominent," "speckling," or "absent." Digital video review was used later to objectively determine precise timing of turbulence onset. The rapid atrial swirl sign (RASS) was defined as the echo appearance of turbulence entering the right atrium immediately (within 2 seconds) after the saline flush of the CVC distal port. The observance of RASS ("positive") was considered "negative" for CVC malposition. Echocardiographic results were compared to CVC tip locations within predetermined zones on the CXR. Superior vena cava (SVC) region was considered the optimal CVC tip position for subclavian and internal jugular CVC. Left CVC tips within the mid left innominate vein were also considered appropriately placed.
RESULTS: A total of 142 patients enrolled, yielding 152 CVCs. Two CVCs were excluded from analysis due to incomplete data. Both CXR and echocardiographic images for 107 internal jugular CVCs and 28 subclavian CVCs were available for analysis. Saline flush echo evaluations were also performed on 15 femoral CVCs. Either 16-cm triple-lumen or 20-cm PreSep CVCs were used. CVC malposition was discovered on CXR in four of 135 (3.0%) of the subclavian and internal jugular CVCs. RASS for subclavian and internal jugular CVC evaluations versus CXR results for CVC tip malposition yielded 75% sensitivity, 100% specificity, positive predictive value (PPV) 100% (95% confidence interval [CI] = 29.24% to 100%), and negative predictive value (NPV) 99.24% (95% CI = 95.85% to 99.98%). Mean (±SD) time for onset of saline flush turbulence was 1.1 (±0.3) seconds for subclavian and internal jugular CVC tips within the target CXR zone.
CONCLUSIONS: The rapid appearance of prominent turbulence in the right atrium on echocardiography after CVC saline flush serves as a precise bedside screening test of optimal CVC tip position.