What condition should be avoided when taking blood pressure on a patient's arm?

When taking blood pressure, it is critical to avoid measuring on the arm that has undergone a mastectomy. This is due to the potential for complications resulting from disrupted lymphatic drainage or the surgical removal of lymph nodes. When blood pressure is measured on the arm of a patient who has had a mastectomy, there is an increased risk of lymphedema, which is a condition characterized by swelling due to the accumulation of lymph fluid. Additionally, the blood flow in that arm may be altered, presenting an inaccurate reading and posing a risk of injury or exacerbating any underlying conditions related to the surgery.

While other conditions listed, like fractures, severe eczema, or thrombosis, may also warrant caution depending on the specific circumstances, they do not carry the same level of risk associated with lymphedema and surgical complications seen in mastectomy patients when taking blood pressure.