A nurse is caring for a 68-year-old patient with COPD exacerbation who is receiving oxygen therapy via nasal cannula at 2 L/min. The patient's oxygen saturation has dropped from 95% to 90% over the past hour, respiratory rate is 30/min, and the patient appears anxious and short of breath. What is the most appropriate nursing intervention?

For COPD patients, oxygen must be titrated carefully to maintain oxygenation (88-92% SpO2) without suppressing hypoxic drive. Increasing to 3-4 L/min with close monitoring balances this need, while higher flows risk respiratory depression.

Clinical Context and Initial Assessment

The patient is presenting with signs of worsening hypoxemia and increased work of breathing during an acute exacerbation of chronic obstructive pulmonary disease (AECOPD). The drop in oxygen saturation from 95% to 90%, accompanied by tachypnea at 30 breaths/min, anxiety, and dyspnea, indicates a decline in respiratory status that requires prompt, measured intervention. In COPD, the primary driver of respiratory drive can shift from the typical hypercapnic response to a hypoxic drive. This means that administering excessive supplemental oxygen can suppress the patient's stimulus to breathe, leading to further carbon dioxide retention and respiratory acidosis. Therefore, the goal of oxygen therapy in AECOPD is to correct hypoxemia to a target saturation range—typically 88% to 92%—without abolishing the hypoxic drive.

Analysis of the Intervention Options

The most appropriate initial step is a cautious titration of oxygen rather than an abrupt, high-flow intervention. Increasing the flow rate to 6 L/min immediately or switching to a non-rebreather mask at 15 L/min poses a significant risk of over-oxygenation, which can precipitate hypercapnic respiratory failure in this population. Conversely, encouraging deep breathing exercises without any adjustment to the failing oxygen delivery device neglects the immediate physiological need for improved oxygenation. The correct approach is to make a modest increase in the current therapy—from 2 L/min to 3-4 L/min—and then closely monitor the patient's response, including repeat oxygen saturation, respiratory rate, work of breathing, and mental status.

Pathophysiological Rationale and Evidence Synthesis

The management strategy is grounded in the delicate balance required during AECOPD. The scoping review by Kristensen et al. underscores that prehospital and emergency management of AECOPD is common but variably supported, highlighting the need for careful, evidence-informed titration of therapies ^[1]. The physiological risk of aggressive oxygenation is further contextualized by studies exploring advanced respiratory support. While the randomized cross-over trials by Guan et al. and Vieira et al. focus on non-invasive ventilation (NIV) and high-flow nasal cannula (HFNC) as modalities for hypercapnic respiratory failure, their underlying principle is relevant: the goal is to reduce breathing effort and improve gas exchange without causing harm [2, 3]. These studies demonstrate that even with advanced interfaces, careful titration is key to optimizing neurophysiological effects and CO2 clearance. In the current scenario, before escalating to such devices, the immediate nursing action is to optimize the existing low-flow oxygen therapy. This aligns with the foundational knowledge expected of emergency nurses, as assessed by Zhao et al., where a strong grasp of oxygen therapy principles directly translates to appropriate and safe clinical practice . A nurse’s ability to recognize the early signs of deterioration and titrate oxygen judiciously is a critical safety intervention that prevents iatrogenic hypercapnia and the potential need for more invasive ventilation.