A nurse is caring for a client with asthma exacerbation who has developed respiratory acidosis. The client's arterial blood gas (ABG) results show: pH 7.22, PaCO2 70 mmHg, HCO3- 28 mEq/L, PaO2 65 mmHg. Which nursing intervention should the nurse implement first?
1Administer sodium bicarbonate as prescribed to correct the acidosis immediately
2Position the client in high Fowler's position and encourage pursed-lip breathing✓ 정답
3Increase the oxygen flow rate to 6 L/min via nasal cannula
4Prepare for immediate endotracheal intubation and mechanical ventilation
해설
Positioning and breathing techniques improve ventilation and CO2 elimination in asthma patients with respiratory acidosis. Other options risk worsening CO2 retention or are too invasive.
The client's ABG reveals a pH of 7.22 (acidosis), a PaCO₂ of 70 mmHg (elevated), and an HCO₃⁻ of 28 mEq/L (slightly elevated but not fully compensating). This pattern indicates an acute respiratory acidosis. The underlying pathophysiology in an asthma exacerbation involves severe bronchoconstriction and airway inflammation, which trap air and increase the work of breathing. The elevated PaCO₂ signals hypoventilation and impending respiratory muscle fatigue, making this a critical situation where improving ventilation, not just oxygenation, is the immediate priority. The PaO₂ of 65 mmHg confirms concurrent hypoxemia, but this is secondary to the primary problem of CO₂ retention.
Prioritizing the First Intervention
In a client with respiratory acidosis from an asthma exacerbation, the nurse must first implement interventions that directly reduce the work of breathing and enhance CO₂ elimination. Positioning the client in high Fowler's position and teaching pursed-lip breathing achieves this by maximizing chest wall expansion and creating positive end-expiratory pressure to keep airways open longer during exhalation. This is a non-invasive, immediate, and independent nursing action that directly targets the cause of the acidosis. Evidence supports that techniques such as pursed-lip breathing and posture training significantly improve ventilatory parameters and reduce complications like atelectasis [1]. A clinical trial protocol even highlights that harmonica playing, which mimics pursed-lip breathing, is being studied for its potential to strengthen respiratory muscles and improve pulmonary health, reinforcing the physiological basis of this technique [4].
Why Other Options Are Not the First Priority
Administering sodium bicarbonate (Option 1) is not the first-line intervention for respiratory acidosis. The problem is retained CO₂, not a primary bicarbonate deficit. Giving bicarbonate could transiently increase CO₂ production as it is buffered, potentially worsening the intracellular acidosis and the client's respiratory status. Increasing oxygen flow rate to 6 L/min (Option 3) addresses hypoxemia but does not solve the hypoventilation. In some clients with chronic CO₂ retention, high-flow oxygen can depress the hypoxic respiratory drive, though this is more of a concern in COPD. The immediate need is to blow off CO₂. Preparing for intubation (Option 4) is a definitive but invasive last resort when non-invasive measures fail. It is not the first action for a client who is still conscious and able to participate in breathing techniques. The nurse must first optimize the client's own ventilatory effort using positioning and controlled breathing strategies, which are foundational components of respiratory rehabilitation shown to enhance both physical and psychological states [1].
References (research sources)
[1]
Perioperative respiratory rehabilitation: evolving concepts and clinical applications.Research articleRhee M, Park S. (2026) · DOI: 10.17085/apm.25338
[4]
Effectiveness of a harmonica-integrated, tele-supervised home-based pulmonary rehabilitation program on lung function and comprehensive health outcomes in patients with chronic obstructive pulmonary disease: a randomized controlled trial protocol.RCT/clinical trialZeng Q, Lin X, Chen W, Fong DYT, Li J, Li J. (2025) · DOI: 10.3389/fpubh.2025.1541866
Clinical Scenario
A client with an acute asthma exacerbation presents with respiratory acidosis (ABG: pH 7.22, PaCO2 70 mmHg, HCO3- 28 mEq/L, PaO2 65 mmHg). The immediate priority is to reduce the work of breathing and enhance CO2 elimination.
Nursing Priority
Position the client in high Fowler's position and instruct on pursed-lip breathing. This non-invasive, independent nursing intervention directly targets the underlying hypoventilation and air trapping by optimizing chest expansion and creating physiologic PEEP.
Step-by-Step Implementation
Assist the client into a high Fowler's position (head of bed 60-90 degrees) to maximize diaphragmatic excursion.
Demonstrate pursed-lip breathing: inhale slowly through the nose, exhale gently through pursed lips (as if blowing out a candle) for twice as long as inhalation.
Coach the client to use this technique during episodes of dyspnea and to prolong exhalation to prevent airway collapse.
Continuously monitor respiratory rate, breath sounds, oxygen saturation, and level of consciousness for signs of improvement or deterioration.
If the client's condition does not improve, prepare to escalate care (e.g., non-invasive ventilation or intubation) as prescribed.
Clinical Reasoning
Administering sodium bicarbonate is contraindicated as first-line therapy for respiratory acidosis because it does not correct the underlying CO2 retention and may worsen intracellular acidosis. Increasing supplemental oxygen alone does not address hypoventilation and may blunt the respiratory drive. Endotracheal intubation is reserved for failure of less invasive measures. The chosen intervention directly improves ventilation, the root cause of the acid-base disturbance.
Respiratory Acidosis — A condition characterized by decreased pH and elevated PaCO2 due to alveolar hypoventilation, leading to CO2 retention.
Pursed-Lip Breathing — A technique that creates mild positive end-expiratory pressure, helping to keep airways open longer during exhalation and reduce air trapping.
High Fowler's Position — A seated position with the head of the bed elevated 60 to 90 degrees, which maximizes chest wall expansion and diaphragmatic excursion.