Nebulisation of Asthalin (Salbutamol) with 3% NaCl
Yes, Asthalin (salbutamol) can be safely nebulised with 3% hypertonic saline, and this combination may provide additional therapeutic benefit compared to normal saline alone, particularly in bronchiolitis and potentially in asthma exacerbations. 1, 2
Evidence-Based Rationale
Standard Diluent Recommendation
- The British Thoracic Society guidelines explicitly state that if the nebuliser system has a residual volume >1.0 ml, the drug volume should be made up with 0.9% sodium chloride (not water) to a minimum of 4.0 ml. 3
- This establishes isotonic (0.9%) saline as the standard diluent for nebulised bronchodilators. 3
Safety of Hypertonic Saline with Salbutamol
- Salbutamol solutions are nearly isotonic and well-tolerated when prepared according to manufacturer recommendations. 4
- Multiple pediatric studies demonstrate that 3% hypertonic saline combined with salbutamol is safe and effective, with no obvious adverse effects reported. 1, 2
- In a randomized controlled trial of 93 infants, nebulized salbutamol 2.5 mg dissolved in 4.0 ml of 3% hypertonic saline showed significantly better outcomes than the same dose in normal saline, with wheezing remission time reduced from 3.8 days to 2.7 days (P < 0.01). 1
Clinical Outcomes
- The combination of salbutamol with 3% hypertonic saline reduced hospital length of stay from 7.4 days to 6.0 days in mild-to-moderate bronchiolitis (P < 0.01). 1
- However, in another study of 120 infants with bronchiolitis, the combination of salbutamol with hypertonic saline did not lead to an additive effect compared to salbutamol with normal saline. 2
- All treatment regimens (including high-volume normal saline alone) showed clinically significant improvement, suggesting the volume of saline may be as important as its tonicity. 5
Practical Implementation
Preparation
- Mix salbutamol 2.5-5 mg with 4.0 ml of 3% NaCl for a total nebulisation volume of approximately 4.5 ml. 1, 2
- This provides adequate volume for most jet nebulisers, which work optimally with drug volumes of 2-5 ml. 3
Administration Technique
- Nebulise until approximately one minute after "spluttering" occurs, which should take 5-10 minutes. 3
- Use oxygen as the driving gas (6-8 L/min) for acute severe asthma to simultaneously treat hypoxemia and bronchospasm. 3, 6
- Use compressed air (not oxygen) for COPD patients with carbon dioxide retention to prevent worsening hypercapnia. 3, 6
Frequency
- For acute severe asthma: every 20-30 minutes for the first hour, then every 4-6 hours. 3, 6
- For COPD exacerbations: every 4-6 hours for 24-48 hours or until clinical improvement. 3
Important Caveats
Bronchospasm Risk
- Non-isotonic solutions can theoretically induce bronchial hyperresponsiveness or severe bronchoconstriction in susceptible patients. 4
- However, clinical trials have not demonstrated this risk when 3% hypertonic saline is combined with salbutamol, likely because the bronchodilator effect of salbutamol counteracts any potential bronchoconstriction from the hypertonic solution. 1, 2
- Solutions can become significantly hypertonic toward the end of nebulisation due to evaporation, but this has not been associated with adverse effects in clinical practice. 4
Patient Selection
- The combination appears most beneficial in non-atopic children with bronchiolitis, while atopic children may benefit more from standard salbutamol with normal saline. 2
- For routine asthma or COPD management, standard 0.9% normal saline remains the guideline-recommended diluent unless specific indications for hypertonic saline exist. 3