A 28-year-old primigravida at 26 weeks gestation presents to the emergency department with acute dyspnea, wheezing, and chest tightness for 6 hours. Vital signs: RR 28/min, SpO2 88% on room air, HR 110/min. Spirometry is performed and shows the pattern marked **C** in the diagram. Arterial blood gas shows pH 7.48, PaCO2 32 mmHg, PaO2 68 mmHg. Which of the following is the most appropriate IMMEDIATE next step in management?

Question

Accepted Answer

D. Administer oxygen to maintain SpO2 ≥95% and initiate nebulized albuterol (salbutamol) with ipratropium bromide. ## Why Option 1 is correct

The spirometry pattern marked **C** (severe obstructive pattern with reversibility) confirms acute asthma exacerbation in this pregnant patient. The clinical anchor is that ACUTE ASTHMA IN PREGNANCY requires AGGRESSIVE TREATMENT because uncontrolled maternal asthma poses GREATER RISKS to mother and fetus than the medications used to treat it. The ABG shows hypocapnia (PaCO2 32 mmHg, which is normal for pregnancy baseline of 28-32 mmHg but indicates ongoing hyperventilation), confirming severe exacerbation. IMMEDIATE management requires: (1) OXYGEN to maintain SpO2 ≥95% (higher target to prevent fetal hypoxia via leftward shift of fetal HbF curve), and (2) SHORT-ACTING BETA-2 AGONISTS (albuterol/salbutamol) as DRUG OF CHOICE, often combined with IPRATROPIUM BROMIDE for severe exacerbations. This approach prevents maternal hypoxemia and fetal hypoxia—the primary dangers in acute asthma in pregnancy. [GINA 2024; ACOG Practice Bulletin Asthma in Pregnancy]

## Why each distractor is wrong

- **Option 2**: Deferring bronchodilators until fetal monitoring is established contradicts the clinical anchor that asthma medications are SAFE in pregnancy and that AGGRESSIVE TREATMENT is required. Delay increases risk of maternal hypoxemia and fetal hypoxia—the exact harms the anchor warns against.
- **Option 3**: While systemic corticosteroids (prednisolone 40-50 mg/day) are part of acute management, they are NOT the immediate first step. Bronchodilators must be initiated simultaneously or first to rapidly improve airway obstruction and oxygenation. Waiting 24 hours risks respiratory failure.
- **Option 4**: Emergency cesarean section is not indicated for asthma exacerbation alone. The anchor emphasizes that asthma is managed medically; cesarean is reserved for obstetric indications or if maternal respiratory failure is imminent despite maximal medical therapy.

**High-Yield:** In acute asthma in pregnancy, the risks of UNTREATED SEVERE ASTHMA (preeclampsia, preterm birth, IUGR, fetal hypoxia) FAR EXCEED the small risks of asthma medications—treat aggressively with SABA + oxygen first, then add systemic corticosteroids.

[GINA 2024; ACOG Practice Bulletin Asthma in Pregnancy]

Answer

A. Administer oral prednisolone 40 mg daily and observe for 24 hours before considering bronchodilators

Answer

B. Perform emergency cesarean section to relieve maternal respiratory compromise

Answer

C. Defer bronchodilators until fetal monitoring is established to avoid teratogenic effects

Explanation

Why Option 1 is correct

Why each distractor is wrong

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