What is a primary consideration when selecting a site for arterial puncture?

When selecting a site for arterial puncture, the presence of collateral circulation is a primary consideration because it ensures that there is an adequate blood supply to the tissue in case the artery is inadvertently occluded during the procedure. Collateral circulation refers to alternative pathways or vessels that can supply blood to a particular area. If a puncture is made in an artery that does not have adequate collateral circulation, there is a risk of ischemia (lack of blood flow) to the surrounding tissues, which can lead to complications.

In contrast, while the size and accessibility of the artery, the average depth of the artery, and the patient's blood pressure are all relevant factors in assessing the site for an arterial puncture, they do not directly influence the risk associated with potential occlusion of blood flow to the tissues. Therefore, ensuring good collateral circulation is vital for patient safety and successful arterial puncture.