II. Pathophysiology
- Oxygen Consumption increases 25% in pregnancy
- Arterial pCO2 falls in pregnancy
- Non-pregnant pCO2 levels are red flags in pregnancy
- Uncontrolled Severe Asthma results in IUGR
- Asthma control in pregnancy is critical
- Bracken (2003) Obstet Gynecol 102:739-52 [PubMed]
III. Admission Criteria
- Arterial pH <7.35 (normal pH 7.40)
- Arterial pCO2 >40 mmHg (normal pCO2 28-32 mmHg)
- Arterial pO2 <70 mmHg
- Pulse >120 beats per minute
- Respiratory Rate >30 breaths per minute
IV. Management: Anti-inflammatory agents
- Outpatient
- Budesonide (Pulmicort) 1-4 puffs bid
- Preferred Inhaled Corticosteroid in pregnancy
- Best studied agent in pregnancy
- Beclomethasone MDI (Vanceril) 2-5 sprays bid-qid
- Flunisolide (Aerobid) 2-4 puffs bid
- Fluticasone (Flovent) 2 puffs bid
- Cromolyn Sodium 2 sprays qid
- Inhaled Corticosteroids are preferred over Cromolyn
- Budesonide (Pulmicort) 1-4 puffs bid
- Outpatient exacerbation management
- Prednisone 40 mg bursts 7-14 days
- Inpatient
- Methylprednisolone 1 mg/kg IV bolus every 6-8 hours
- Precautions: Prednisone and Methylprednisolone
- Use systemic steroids sparingly in first trimester
- Risk of Cleft Palate, IUGR, and Preterm Labor
V. Management: Bronchodilator agents
- Outpatient
- Albuterol 2 puffs every 4 hours prn
- Montelukast (Singulair)
- Zafirlukast (Accolate)
- Inpatient
- Albuterol Nebulizer 2.5 mg in 3 cc Normal Saline
- Theophylline (rarely used now)
- Emergent Management
- Epinephrine (1:1000)
- Dose: 0.01 ml/kg to 0.2-0.5 ml SC every 30 min prn
- Epinephrine (1:1000)