A nurse is caring for a client with chronic obstructive pulmonary disease (COPD) who is receiving oxygen via nasal cannula at 2 L/min. During morning rounds, the client reports feeling more short of breath than usual. The nurse observes that the client is slightly drowsy and has a respiratory rate of 10 breaths per minute. Which of the following actions should the nurse perform first?

A. Administer a prescribed bronchodilator medication to open the airways: Immediate administration of bronchodilators without assessing the current oxygenation status may overlook the most urgent problem. The client’s drowsiness and bradypnea suggest potential hypoventilation or oxygen-induced hypercapnia, requiring assessment before medication. B. Assess the client's oxygen saturation level using a pulse oximeter: The first action is to evaluate the client’s oxygenation objectively. Measuring SpO₂ provides critical data to determine the severity of hypoxemia and guides safe interventions. In COPD patients, oxygen adjustments must be carefully titrated to avoid worsening CO₂ retention, making assessment the priority. C. Increase the oxygen flow rate to 4 L/min to improve oxygenation: Increasing oxygen without assessing saturation may risk suppressing the hypoxic drive in a COPD patient, leading to further CO₂ retention and respiratory depression. Oxygen titration should follow assessment of SpO₂ and clinical status. D. Reposition the head of the bed to the Semi-Fowler position: Repositioning can enhance lung expansion and ease breathing, but it does not address the immediate need to determine the client’s oxygenation status or the risk of worsening respiratory depression. Assessment takes precedence to guide appropriate interventions.