When drawing blood from a central venous access device with all ports patent, which lumen should the nurse select?

Choosing the distal port when drawing blood from a central venous access device is the correct practice because the distal port is generally the designated port for blood withdrawal. This is due to its positioning and the way the catheter is designed. The distal port typically has the largest diameter and is furthest from the heart, making it the most effective site for drawing blood. This helps to minimize the risk of contamination and ensures that the sample is representative of the patient’s central circulation.

In contrast, the proximal and middle ports, while still functional, may be used for other purposes such as administering medications or fluids, which could potentially compromise the integrity of the blood sample. Selecting the distal port ensures that the blood drawn is fresh and not influenced by infusions or other substances that may be present in the other ports. It is crucial for maintaining quality and accuracy in the results of laboratory tests ordered based on the blood drawn.