What are the indications and contraindications for nebulisation (nebulizer) therapy, including medications such as salbutamol (albuterol) and ipratropium bromide?

Nebulization Drugs: Indications and Contraindications

Nebulizer therapy is primarily indicated for acute severe asthma and COPD exacerbations when patients cannot effectively use hand-held inhalers due to symptom severity, require large drug doses, have difficulty with coordinated breathing, or when hand-held inhalers have proven ineffective despite proper technique. 1

Main Nebulization Medications

Salbutamol (Albuterol)

Indications:

• Acute severe asthma in adults and children
• COPD exacerbations
• Chronic persistent asthma (after formal evaluation)
• "Brittle" asthma (for self-treatment of sudden attacks)

Dosage:

• Adults: 5 mg repeated every 4-6 hours
• Children: 5 mg (or 0.15 mg/kg) repeated every 1-4 hours 2, 1

Contraindications:

• Hypersensitivity to salbutamol
• Caution in patients with:
  • Cardiovascular disorders (coronary insufficiency, arrhythmias, hypertension)
  • Convulsive disorders
  • Hyperthyroidism
  • Diabetes mellitus
  • Unusual responsiveness to sympathomimetic amines 3

Ipratropium Bromide

Indications:

• Add-on therapy for acute severe asthma not responding to β-agonists
• COPD exacerbations
• Combined therapy with salbutamol for enhanced bronchodilation

Dosage:

• Adults: 500 μg added to β-agonist
• Children: 250 μg added to β-agonist 2, 1

Contraindications:

• Hypersensitivity to ipratropium, atropine, or its derivatives
• Caution in patients with glaucoma (use mouthpiece rather than mask) 4

Clinical Decision Algorithm for Nebulization Therapy

1. Acute Severe Asthma

Adults (any of these criteria):

• Cannot complete sentences
• Respiratory rate >25/min
• Heart rate >110/min
• PEF <50% of best

Treatment:

• Oxygen plus oral steroids
• Nebulized salbutamol 5 mg or terbutaline 10 mg every 4-6 hours
• If not improving, add ipratropium bromide 500 μg to the β-agonist 2

Children (any of these criteria):

• Cannot talk or feed
• Respiratory rate >50/min
• Heart rate >140/min
• PEF <50% predicted

Treatment:

• Oxygen plus nebulized salbutamol 5 mg (or 0.15 mg/kg) or terbutaline 10 mg (or 0.3 mg/kg) every 1-4 hours
• If not improving after 30 minutes, add ipratropium bromide 250 μg
• Continue hourly and consider hospital transfer and oral steroids 2

2. COPD Exacerbations

Severe (any of these criteria):

• Cyanosis
• Respiratory rate >25/min
• Cannot make sentences
• Reduced activity

Treatment:

• Consider hospital admission
• Nebulize β-agonists as for acute asthma or ipratropium bromide 250-500 μg every 4-6 hours
• If more severe or not improving, combine a β-agonist with ipratropium bromide 500 μg every 4-6 hours
• Use 24% Venturi mask between treatments 2

Evidence for Combined Therapy

Research shows that combining salbutamol and ipratropium bromide provides greater bronchodilation than salbutamol alone in acute severe asthma. A study demonstrated that the percentage increase in peak flow was about 32% greater in the combination group compared to salbutamol alone at 60 minutes post-treatment 5. Another pooled analysis found that adding ipratropium to salbutamol reduced the risk of needing additional treatment, subsequent asthma exacerbations, and hospitalizations 6.

Special Considerations

Elderly Patients:

• β-agonists may rarely precipitate angina (first treatment should be supervised)
• For patients with glaucoma using ipratropium, use a mouthpiece rather than a mask to prevent exacerbation of glaucoma 2, 1

Monitoring and Side Effects:

• Monitor for tachycardia, tremor, and hypokalemia, especially with higher or more frequent dosing
• Measure arterial blood gas tensions in severely ill patients requiring hospitalization
• Large doses of albuterol may aggravate pre-existing diabetes mellitus and ketoacidosis 1, 3

Maintenance and Equipment:

• Disposable components should be changed every 3-4 months
• Compressors need annual servicing
• Patients should know how to troubleshoot equipment problems and have a backup plan (multiple doses of hand-held inhalers) 2

Important Caveats

1. Regular preventative treatment should not be discontinued when using a nebulizer for acute symptoms.

2. Back-to-back nebulizations should be avoided due to increased risk of side effects and potential for paradoxical bronchospasm.

3. For long-term use, nebulizer therapy should only be initiated after formal evaluation of its benefit and when hand-held inhalers at appropriate doses have failed.

4. Drug compatibility and safety when mixing medications other than salbutamol and ipratropium in a nebulizer have not been established.

5. Patients should be instructed on proper nebulizer use, with the first treatment always done under supervision.