What interpretation should the nurse make when edema is noted in the foot below a cast?

When edema is observed in the foot below a cast, the interpretation of impaired venous return is correct due to several physiological reasons.

A cast is applied to immobilize a body part, which can restrict normal blood flow and drainage routes for fluids. In this scenario, the compliance of the tissues beneath the cast decreases, leading to increased pressure in the venous system. When venous return is impaired, blood and interstitial fluid can accumulate in the lower extremities, resulting in swelling or edema.

This phenomenon can be exacerbated by factors such as gravity and lack of mobility, both of which can further hinder the return of venous blood from the feet back to the heart. Therefore, the observation of edema below the cast typically indicates that there is an issue with venous drainage in that area, encapsulating the concept of impaired venous return.

The other options do not align with the physiological processes involved in this scenario. Impaired arterial flow would suggest ischemia or lack of blood supply, which would not manifest as dependent edema. Increased venous return is counterintuitive under these circumstances, as the presence of a cast predominantly limits effective venous drainage. While some fluid accumulation might be normal in certain contexts, in the presence of a cast