Final answer:
The nurse should first measure the reddened area on the skin surface to document the extent of the infection or inflammation before considering other interventions.
Step-by-step explanation:
When a nurse observes a small opening draining purulent material on the skin, especially in a bedridden client, the nurse's next best action is to measure the reddened area on the skin surface. This is a vital initial step to document the extent of the infection or inflammation.
Applying a dressing, probing, or other interventions might be warranted afterward depending on the extent of the wound and the clinical judgment of the healthcare provider. However, probing for necrotic tissue should be done with caution and typically by a healthcare provider with expertise in wound management. A transparent film dressing is generally not appropriate for wounds with heavy drainage, whereas alginate dressings may be suitable if there's significant exudate as they are highly absorbent, but again, the initial step is to assess and measure the area.
It's also important to note that such openings over bony prominences could be indicative of underlying pressure ulcers or infections that require immediate medical attention to prevent further deterioration, such as necrotizing fasciitis or gas gangrene.