Methods for determining the internal volume of central venous catheters

A prevalent problem associated with central venous catheters (CVCs) is occlusion with clotted blood or drug precipitate. When an occlusion occurs, the inability to determine a CVC's internal volume may seriously delay instillation of a precise quantity of a corrective drug. A lack of standards for CVC measurements and confusion about terminology for describing catheter geometry are partly to blame. This article aims to alleviate the problem, providing three methods for determining CVC internal volume with two reference tables and mathematical support for all calculations. A glossary of CVC terms is also included.