A nurse is monitoring a client who has a cast on their right ankle following an open reduction and internal fixation procedure. The nurse should monitor for which findings that indicate compartment syndrome?

A. Decreased oxygen saturation: Reduced oxygen saturation reflects impaired respiratory or systemic oxygenation rather than a localized vascular compromise. Compartment syndrome is a limb-threatening condition caused by increased pressure within a closed muscle compartment, so systemic hypoxia is not a primary indicator. B. Dyspnea and bibasilar crackles: These findings are more consistent with pulmonary conditions such as fluid overload, pneumonia, or heart failure. Compartment syndrome presents with localized extremity findings rather than respiratory symptoms, these signs do not indicate the condition. C. Pain unrelieved by routine medications: Severe, persistent pain that is disproportionate to the injury and not relieved by analgesics is a hallmark early sign of compartment syndrome. It results from increased intracompartmental pressure compromising blood flow and nerve function, requiring immediate intervention to prevent permanent damage. D. Elevated leukocyte count: An increased white blood cell count may indicate infection or inflammation but is not a specific or early sign of compartment syndrome. The condition is primarily identified through clinical assessment of pain, perfusion, sensation, and motor function rather than laboratory values.