What is the treatment for status asthmaticus in adults?

Treatment of Status Asthmaticus in Adults

The immediate treatment of status asthmaticus in adults requires high-flow oxygen, high-dose inhaled β-agonists, systemic corticosteroids, and consideration of adjunctive therapies such as ipratropium bromide to prevent mortality and restore lung function as quickly as possible. 1

Assessment of Severity

Status asthmaticus is defined as severe asthma unresponsive to repeated courses of beta-agonist therapy 2. Proper assessment is critical for management:

Features of Severe Asthma:

• Too breathless to complete sentences in one breath
• Respiratory rate >25 breaths/min
• Peak expiratory flow (PEF) <50% of predicted normal or best
• Heart rate >110 beats/min 1

Life-Threatening Features:

• PEF <33% of predicted normal or best
• Silent chest, cyanosis, or feeble respiratory effort
• Bradycardia or hypotension
• Exhaustion, confusion, or coma 1

Arterial Blood Gas Markers of Severity:

• Normal or high PaCO₂ (5-6 kPa) in a breathless asthmatic
• Severe hypoxia: PaO₂ <8 kPa despite oxygen therapy
• Low pH (acidosis) 1

Immediate Management Algorithm

1. High-Flow Oxygen

   • Administer immediately to maintain oxygen saturation >90% 1

2. High-Dose Inhaled β-agonists

   • Give salbutamol 5 mg or terbutaline 10 mg via nebulizer with oxygen
   • Can be administered via multiple actuations of metered dose inhaler into spacer (2 puffs 10-20 times) if nebulizer unavailable
   • Albuterol (salbutamol) is the most commonly used β₂-selective inhaled bronchodilator 3
   • For adults, standard dose is 2.5 mg administered 3-4 times daily by nebulization 4
   • In status asthmaticus, may need to administer more frequently (up to every 15-30 minutes) 1

3. Systemic Corticosteroids

   • Administer immediately: prednisolone 30-60 mg orally or hydrocortisone 200 mg IV 1
   • Should be given as early as possible as clinical benefits may take 6-12 hours to appear 2, 5
   • Continue high-dose steroids: prednisolone 30-60 mg daily or IV hydrocortisone 200 mg every six hours 1
   • Oral administration is as effective as IV administration 1

4. For Life-Threatening Features, Add:

   • Ipratropium bromide 0.5 mg nebulized with β-agonist 1
   • Consider IV aminophylline (250 mg over 20 minutes) or IV salbutamol/terbutaline (250 μg over 10 minutes)
   • Caution: Do not give bolus aminophylline to patients already taking oral theophyllines 1

Monitoring Treatment

1. Measure and record PEF 15-30 minutes after starting treatment and regularly thereafter
2. Continue oxygen therapy
3. If improving: give nebulized β-agonist every 4 hours
4. If not improving after 15-30 minutes: give nebulized β-agonists more frequently (up to every 15 minutes)
5. If still unsatisfactory progress: consider aminophylline or parenteral β-agonist 1

Subsequent Management

If Patient Is Improving:

• Continue high-flow oxygen
• Continue prednisolone 1-2 mg/kg daily (maximum 40 mg)
• Continue nebulized β-agonist 4-hourly 1

If Patient Is Not Improving After 15-30 Minutes:

• Continue oxygen and steroids
• Give nebulized β-agonist more frequently (up to every 30 minutes)
• Add ipratropium to nebulizer and repeat 6-hourly until improvement starts 1

Criteria for ICU Transfer

Transfer to intensive care unit (accompanied by a doctor prepared to intubate) if:

• Deteriorating PEF
• Worsening exhaustion, feeble respirations
• Persistent hypoxia or hypercapnia
• Coma, respiratory arrest, confusion, or drowsiness 1

Mechanical Ventilation

If respiratory failure develops despite maximal therapy:

• The ventilation strategy should aim to avoid dynamic hyperinflation by enhancing expiratory time
• Complications to watch for include hypotension and barotrauma
• Sedation with opioids, benzodiazepines, or propofol may be required to facilitate ventilator synchrony
• Avoid neuromuscular blockade if possible due to risk of myopathy 3

Discharge Criteria

Patients should only be discharged when:

• They have been on discharge medication for 24 hours with inhaler technique checked
• PEF >75% of predicted or best and PEF diurnal variability <25%
• Treatment includes oral steroids and inhaled steroids in addition to bronchodilators
• They have a PEF meter and self-management plan
• Follow-up with primary care is arranged within 1 week 1

Common Pitfalls to Avoid

1. Underestimating severity: The severity of asthma attacks is often underestimated by patients, relatives, and doctors 1

2. Delaying corticosteroids: Administer systemic corticosteroids early as benefits may take 6-12 hours to appear 2

3. Inappropriate sedation: Any sedation is contraindicated in status asthmaticus 1

4. Overuse of antibiotics: Give antibiotics only if bacterial infection is present 1

5. Inadequate monitoring: Physicians' subjective assessments of airway obstruction are often inaccurate; use objective measures like PEF and pulse oximetry 2

6. Premature discharge: Ensure patients meet all discharge criteria and have a clear follow-up plan 1