Acute Severe Asthma Exacerbation Disposition
A 17-year-old male with persistent asthma presents with 6 hours of worsening breathlessness. He speaks in single words, respiratory rate is 32 breaths/min and oxygen saturation 89 % on 6 L/min of oxygen. After systemic corticosteroid, repeated nebulized bronchodilators and intravenous magnesium sulfate there is no improvement at 1 hour. Arterial blood gas shows pH 7.30 and PaCO₂ 50 mm Hg. What is the most appropriate next step in management?
- A.Discharge on oral prednisolone
- B.Admit to a general medical ward
- C.Admit to the intensive care unitCorrect
- D.Discharge with next-day clinic review
Explanation
This patient has life-threatening asthma that has failed maximal initial therapy, and the correct disposition is the intensive care unit for continuous monitoring and assessment of the need for non-invasive or invasive ventilation. The markers of severity are all present: inability to speak in sentences, respiratory rate above 30 breaths/min, pulse above 120 beats/min, oxygen saturation below 92 % despite supplemental oxygen, and above all a normal to rising PaCO₂ with acidemia. During a severe exacerbation, tachypnea should drive PaCO₂ down, so a PaCO₂ of 50 mm Hg with a pH of 7.30 signals respiratory muscle fatigue and impending respiratory arrest rather than improvement. Hyperinflation on the radiograph reflects severe dynamic air trapping, which raises intrathoracic pressure and increases the risk of barotrauma and hypotension if the patient is intubated. Ward-level care lacks the nursing ratio, continuous capnography and immediate airway expertise needed if he deteriorates over the next hour. Discharge in any form would be dangerous, since failure to respond to systemic steroids, repeated beta-2 agonists and magnesium is precisely the profile of near-fatal asthma and a prior admission is an independent risk factor for death. In the unit, therapy continues with high-dose inhaled bronchodilators, systemic corticosteroid and controlled oxygen targeting a saturation of 93 % to 95 %, with a low threshold for intubation using a lung-protective, low-respiratory-rate strategy to allow full expiration.
Why each option
- A.
- Discharge with oral steroids is only for patients who improve substantially and maintain adequate saturation and peak flow after treatment.
- B.
- A general ward cannot provide the continuous monitoring and immediate airway support that this patient may need within the hour.
- C.
- Correct. A rising PaCO₂ with acidemia after failure of maximal medical therapy indicates impending respiratory failure requiring intensive care monitoring.
- D.
- Deferring reassessment to the next day would leave a patient with impending respiratory arrest unmonitored.
Reference: Global Initiative for Asthma (GINA) Report, 2024, Management of acute asthma exacerbations
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