An older adult client who resides in a long-term care facility is incontinent of urine and has a stage II pressure injury on the left heel. When the client becomes confused, which assessment is most important for the nurse to obtain?

A. Amount of serous drainage from left heel: A stage II pressure injury may produce serous drainage due to partial-thickness skin loss involving the epidermis and possibly the dermis. Monitoring drainage helps evaluate wound healing and infection risk. However, drainage from a localized wound does not directly explain acute confusion. B. White blood cell count (WBC): Acute confusion in older adults is often a manifestation of delirium, frequently caused by infection. Residents of long-term care facilities are particularly susceptible to infections such as urinary tract infections, wound infections, or sepsis. An elevated WBC count can indicate systemic infection and help identify a possible cause of the sudden mental status change, making it the most important assessment. C. Urinary output for past six hours: Monitoring urinary output provides information about renal perfusion and fluid balance and may help detect dehydration or renal dysfunction. Although these factors can contribute to confusion, urinary output alone does not directly identify the most common acute cause of delirium in older adults, which is infection. D. 24-hour medication history: Reviewing medications is useful because certain drugs, such as sedatives, anticholinergics, or opioids, can cause confusion or delirium in older adults. However, medication review occurs after initial evaluation for more urgent physiological causes. Since infection is a leading cause of sudden confusion, assessing WBC count takes higher priority.