For which of the following patients would it be necessary to use a disposable shampoo cap, rather than a shampoo board?

Using a disposable shampoo cap is suitable for patients who may have certain medical devices or conditions that make traditional shampooing methods, like a shampoo board, less practical or safe. In this case, the older adult woman with a drainage tube following a mastectomy falls into this category because her condition requires careful handling to avoid disrupting the drainage tube, which is critical for her healing process. The disposable shampoo cap allows for cleaning the hair without the risk of water and potentially harmful substances interfering with her medical equipment or injury.

This is especially relevant given her situation, as any unnecessary manipulation around her surgical site could risk complications or infection. On the other hand, while other patients might benefit from different methods, they do not have the same immediate concerns related to surgical drains that necessitate the use of a disposable shampoo cap for safety and convenience.