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Difficulty: MediumPhysiological Adaptation

During continuous monitoring of an individual experiencing a severe asthma exacerbation, the nurse notes prominent accessory muscle use, diaphoresis, and a respiratory rate of 3232 breaths per minute. A recent assessment of lung sounds indicates a marked reduction in bilateral wheezing compared to baseline. The concurrent arterial blood gas (ABG) panel on room air yields a pH of 7.397.39, a PaCO2\text{PaCO}_2 of 41 mm Hg41\text{ mm Hg}, and a PaO2\text{PaO}_2 of 58 mm Hg58\text{ mm Hg}. What is the priority nursing intervention in this scenario?

  1. Activate the rapid response team and prepare for immediate airway management.Answer
  2. B
    Continue the current nebulizer treatments as the acid-base balance is normalizing.
  3. C
    Lower the head of the bed to facilitate increased blood flow to the pulmonary vasculature.
  4. D
    Instruct the individual to take slow, deep breaths to correct the respiratory alkalosis.

Answer

The priority action is to activate the rapid response team and prepare for immediate airway management due to signs of impending respiratory failure.
The client is exhibiting signs of impending respiratory failure. In early asthma attacks, hyperventilation causes respiratory alkalosis (low carbon dioxide, high pH). As the client fatigues, ventilation decreases, leading to a 'normalizing' carbon dioxide and pH level. This is known as a 'pseudonormal' ABG. Combined with diminished lung sounds (a 'silent chest') and hypoxemia, this indicates severe airway obstruction and muscle exhaustion requiring immediate mechanical ventilation.

Step-by-Step Solution

1
Analyze the physical assessment findings.
The client shows severe work of breathing (accessory muscle use, tachypnea) but a sudden decrease in wheezing.
A 'silent chest' or marked reduction in wheezing during an exacerbation implies that airflow is so severely restricted that wheezes can no longer be produced.
2
Interpret the arterial blood gas (ABG) results in the context of the physical assessment.
The pH (7.397.39) and PaCO2\text{PaCO}_2 (41 mm Hg41\text{ mm Hg}) are within normal limits, while the PaO2\text{PaO}_2 (58 mm Hg58\text{ mm Hg}) indicates severe hypoxemia.
Early in an asthma attack, tachypnea causes hyperventilation and respiratory alkalosis (low PaCO2\text{PaCO}_2). As the client fatigues, they can no longer blow off carbon dioxide, causing the PaCO2\text{PaCO}_2 to rise back to 'normal' levels before progressing to respiratory acidosis.
3
Determine the priority clinical intervention.
Immediate escalation of care and preparation for endotracheal intubation.
The combination of a 'pseudonormal' ABG and a silent chest is an ominous sign of extreme muscle fatigue and impending respiratory arrest, necessitating advanced airway support.

Key Concept

Interpretation of 'Pseudonormal' ABGs in Acute Asthma
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Topics

Physiological Adaptation

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