Venous patency after open central-venous cannulation.

To investigate the value of Doppler ultrasound scan (USS) assessment of internal jugular vein (IJV) patency after previous open central-venous cannulation (CVC), a prospective study of 66 consecutive children (median age 4.5 years; range 4 months-17 years) who had previously undergone open insertion of at least one indwelling IJV line and required further CVC for completion of therapy was undertaken. All underwent Doppler USS examination prior to surgery. Where patency of the previously cannulated vein was suggested ultrasonographically, the accuracy of this finding was confined at open surgical exploration. Initial CVCs were in situ for a median of 9 months (1 month-4 years) prior to removal. The median interval to repeated CVC was 11 months (3 weeks-45 months). In 79 Doppler USS, 70 (88.6%) veins appeared patent, 3 (4.2%) stenosed, and 6 (7.6%) obliterated. Of the 70 "USS patent" veins, 66 were explored. Patency was confirmed surgically in 59 (89.4%) and a new CVC successfully inserted. Seven (10.6%) apparently patent veins on USS were found to be obliterated at open exploration. Review of USS images in these cases suggested that enlarged collateral veins were usually responsible. Overall, successful recannulation was possible in 74.6% of all previously accessed veins. In children requiring repeated CVC, Doppler USS of neck veins is a valuable but not entirely reliable guide to the presence of underlying vessel patency and should be interpreted with caution. At least three-fourths of previously cannulated IJVs remain patent after catheter removal and can be reused for CVC.