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Zorluk: OrtaPhysiological Adaptation

A nurse is caring for a client admitted with an acute severe asthma exacerbation. Upon admission, the client was anxious and tachypneic with a respiratory rate of 34/min, and auscultation revealed loud, diffuse bilateral wheezing. Two hours later, the nurse notes that the client is now lethargic, the respiratory rate has decreased to 14/min, and breath sounds are markedly diminished. Which of the following arterial blood gas (ABG) results should the nurse anticipate based on the client's current clinical status?

  1. A
    pH 7.54, PaCO2 28 mm Hg, PaO2 72 mm Hg, HCO3- 22 mEq/L
  2. pH 7.28, PaCO2 58 mm Hg, PaO2 55 mm Hg, HCO3- 25 mEq/LCevap
  3. C
    pH 7.42, PaCO2 38 mm Hg, PaO2 96 mm Hg, HCO3- 24 mEq/L
  4. D
    pH 7.32, PaCO2 35 mm Hg, PaO2 88 mm Hg, HCO3- 16 mEq/L

Cevap

The ABG showing a pH of 7.28, elevated PaCO2 of 58 mm Hg, and normal HCO3- of 25 mEq/L (uncompensated respiratory acidosis) best reflects the client's clinical deterioration.
The client is exhibiting signs of impending respiratory failure, often referred to as a 'silent chest'. The exhaustion of respiratory muscles leads to alveolar hypoventilation. As ventilation drops, carbon dioxide is retained, causing the PaCO2 to rise and the pH to fall. The correct ABG reflects uncompensated respiratory acidosis (low pH, high PaCO2, normal HCO3-), which directly aligns with the lethargy and bradypnea described in the stem.

Adım Adım Çözüm

1
Analyze the change in the client's clinical presentation.
The client transitioned from anxious, tachypneic, and actively wheezing to lethargic with a decreased respiratory rate and 'silent chest' (diminished breath sounds).
Tracking clinical trends is essential to determine whether the client is improving or deteriorating.
2
Interpret the physiological meaning of the current findings.
Lethargy, a falling respiratory rate, and absent wheezing in a severe asthma attack indicate severe bronchospasm, respiratory muscle fatigue, and an inability to maintain adequate ventilation.
A 'silent chest' is a classic sign of impending respiratory failure, meaning air movement is severely compromised.
3
Correlate the physical findings with anticipated ABG changes.
Inadequate ventilation leads to carbon dioxide retention (hypercapnia), which drops the blood pH, resulting in respiratory acidosis.
Hypoventilation directly causes a primary accumulation of PaCO2, and because it is an acute event, the kidneys have not had time to compensate with HCO3- retention.

Anahtar Kavram

During an asthma exacerbation, a transition from hyperventilation (respiratory alkalosis) to hypoventilation (respiratory acidosis) accompanied by a 'silent chest' and lethargy signals impending respiratory failure.
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Konular

Physiological Adaptation

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