RESUMO
INTRODUCTION: Correct tip positioning is a critical aspect in central vascular access devices insertion. The verification of positioning at the cavo-atrial junction is usually performed by intracavitary electrocardiography. Recently, echocardiographic techniques were proposed, including the direct visualization of the catheter or the visualization of a saline/air bolus (i.e. "bubble test"). As for the latter, a push-to-bubbles delay time below 2 s was proposed to indicate a correct positioning of the catheter tip. The aim of this study was to measure the variations of the push-to-bubbles time at increasing distance from the cavo-atrial junction, to verify if a cut-off of 1-2 s correspond to a well-positioned catheter. METHODS: We performed a prospective study including patients with clinical indication of positioning a peripherally inserted central catheter. The catheter tip was positioned at the cavo-atrial junction (P0) via intracavitary electrocardiography, and the push-to-bubbles delay time was measured. The catheter was then retracted 5 cm (P1) and 10 cm (P2), and the test was repeated at this positioning. Push-to-bubbles time measurements were performed off-line by analyzing an audio/video recording which included the echography screen and the voice signal of the operator. RESULTS: Forty-nine patients were included. The average push-to-bubble time when the catheter tip was in the reference position was 0.41 ± 0.21 s. Retraction of the PICC catheter of 5 and 10 cm determined a significant increase of the push-to-bubbles time: mean time difference was +0.34 (95% IC 0.25-0.43, p < 0.001) s between P0 and P1 (5 cm distance), and +0.77 (95% IC 0.62-0.92, p < 0.001) s between P0 and P2 (10 cm distance). When the catheter was at the reference position (i.e. cavo-atrial junction) only 2.1% of bubbles delay times were above 1 s. CONCLUSION: The push-to-bubbles time is very low when the catheter tip is at the cavo-atrial junction. This delay increases progressively with increasing distance from the target. Push-to-bubbles delay time above 1 s might indicate a catheter not close to the cavo-atrial junction.
RESUMO
Femorally inserted Central Catheters are increasingly used also for medium and long-term catheterization as an alternative to Centrally and Peripherally inserted Central Catheters. If certified as "power injectable," they may be used for contrast media injection during radiological examinations. It is important to consider the risk that, as with other types of catheters, the injection of contrast media could cause migration or damage to the device. The case of a Femoral catheter migration in hepatic vein, during CT scan, is described.
