A nurse is caring for a patient with chronic obstructive pulmonary disease (COPD) who presents with the following arterial blood gas (ABG) results: pH 7.32, PaCO2 58 mmHg, HCO3- 30 mEq/L, PaO2 65 mmHg. The patient appears drowsy and has shallow respirations at 10 breaths per minute, indicating potential respiratory failure. What is the nurse's priority action?

The patient with COPD presents with drowsiness and shallow respirations at a rate of 10 breaths per minute. The ABG reveals a pH of 7.32, PaCO₂ of 58 mmHg, and HCO₃⁻ of 30 mEq/L. This pattern indicates a primary acute-on-chronic respiratory acidosis. The pH is below 7.35, confirming acidemia. While the elevated HCO₃⁻ suggests metabolic compensation (likely from chronic CO₂ retention), the pH has not normalized, pointing to an acute decompensation. The elevated PaCO₂ is the primary problem, signifying hypoventilation. The patient's altered mental status (drowsiness) and bradypnea are critical indicators of ventilatory failure, a state where the respiratory muscles can no longer sustain adequate alveolar ventilation to eliminate CO₂.

In the context of ventilatory failure with hypercapnia and altered consciousness, the immediate priority is to support ventilation to correct the life-threatening respiratory acidosis. The patient's shallow, slow respirations are insufficient. Bag-mask ventilation or preparation for mechanical ventilation provides immediate positive-pressure support, increasing tidal volume and minute ventilation to blow off CO₂ and restore a safer pH. This directly addresses the root cause of the decompensation. The evidence underscores that timely application of ventilatory support, such as non-invasive ventilation (NIV) or invasive mechanical ventilation, is a cornerstone of managing acute exacerbations of COPD with respiratory failure ^[1]. The interprofessional team, including nurses, respiratory therapists, and physicians, must recognize the signs of impending respiratory arrest and act swiftly to initiate this life-saving intervention.

1. Administer high-flow oxygen at 15 L/min via non-rebreather mask: This action is dangerous in a patient with chronic CO₂ retention. While the PaO₂ of 65 mmHg indicates hypoxemia, the primary driver for breathing in some COPD patients may shift from hypercapnia to the hypoxic drive. Uncontrolled high-flow oxygen can suppress the respiratory drive, leading to further hypoventilation, worsening hypercapnia, and potential respiratory arrest. Oxygen therapy must be carefully titrated to a target saturation (often 88-92%) using a controlled device like a Venturi mask.


2. Encourage deep breathing exercises and use of incentive spirometer: This intervention is inappropriate for a drowsy patient with a declining level of consciousness and severe hypoventilation. An incentive spirometer is designed for patients who are alert, cooperative, and able to follow commands to prevent atelectasis, not to treat acute ventilatory failure. This patient lacks the mental status and respiratory muscle strength to participate in this therapy.


3. Position the patient in Trendelenburg position to improve ventilation: The Trendelenburg position (head down, feet elevated) would worsen the patient's respiratory status. It forces abdominal contents against the diaphragm, limiting its excursion and further reducing lung volumes and ventilation. The appropriate position to optimize breathing in a COPD patient is upright, such as high-Fowler's or the tripod position, which aids diaphragmatic descent and chest expansion.