Which catheter is described as a thin, flexible, flow-directed multi-lumen tube positioned in a pulmonary artery?

The description given in the question refers specifically to the Swan-Ganz catheter, which is indeed a thin, flexible, flow-directed multi-lumen tube used for monitoring pressure in the pulmonary artery. This catheter plays a critical role in hemodynamic monitoring and is typically utilized in critical care settings to assess patients' cardiovascular status.

The Swan-Ganz catheter consists of multiple lumens, allowing for various therapeutic and diagnostic functions. These include measuring pulmonary artery pressures and obtaining mixed venous blood samples, which are essential for evaluating oxygenation and overall cardiac function.

Other catheter types listed do not match this description. Internal catheters can refer to various catheter types used inside the body but do not specifically indicate a pulmonary artery function. An implanted port is designed for easy venous access, often for chemotherapy, which differs significantly from the function of a Swan-Ganz catheter. An intra-arterial cannula, while it is used for arterial access, does not possess the flow-directed characteristics or the multi-lumen design that defines the Swan-Ganz catheter.

Understanding these distinctions is vital for effective medical coding, as accurately identifying and coding procedures or devices based on their specific characteristics and uses is essential for maintaining proper documentation and reimbursement processes.