What is the therapeutic dose of nebulised salbutamol (2 mg/5 ml) for an 11‑month‑old infant?

Therapeutic Dose of Nebulised Salbutamol for an 11-Month-Old Infant

For an 11-month-old infant with acute wheezing or asthma, administer nebulised salbutamol at 0.15 mg/kg (minimum 2.5 mg) every 20 minutes for three doses, then every 1–4 hours as needed. 1

Weight-Based Dosing Protocol

• Calculate the dose as 0.15 mg/kg of the infant's body weight, with a minimum dose of 2.5 mg regardless of weight. 1
• For an average 11-month-old weighing approximately 9–10 kg, this translates to 1.35–1.5 mg per dose, but the minimum 2.5 mg dose should be used in practice. 1
• Given your 2 mg/5 mL formulation, administer 6.25 mL (which delivers 2.5 mg salbutamol) per nebulisation. 1

Nebuliser Preparation and Administration

• Dilute the salbutamol solution to a minimum total volume of 3 mL (add normal saline if needed) to ensure adequate aerosol generation. 2
• Use an oxygen-driven nebuliser with a flow rate of 6–8 L/min whenever possible, especially in severe respiratory distress, to prevent hypoxia during treatment. 1, 2
• Administer via a properly fitting face mask to maximize drug delivery in this age group. 2

Dosing Frequency for Acute Exacerbations

• Initial management: Give the dose every 20 minutes for three consecutive treatments (total duration approximately 60 minutes). 1, 2
• After the first three doses: Continue every 1–4 hours as needed based on clinical response (respiratory rate, oxygen saturation, work of breathing, wheeze). 1, 2
• For severe or life-threatening bronchospasm, the 20-minute interval may be extended beyond three doses until improvement occurs. 2

Adding Ipratropium for Severe Cases

• If the infant presents with moderate-to-severe respiratory distress (respiratory rate >50/min, use of accessory muscles, inability to feed, oxygen saturation <90%), add ipratropium bromide 250 µg to each of the first three nebulised treatments. 1, 2
• The British Thoracic Society guidelines recommend half doses (approximately 100–125 µg) of ipratropium in very young children, though 250 µg is the standard pediatric dose cited. 1
• After the initial three combination doses, continue ipratropium every 6 hours if further bronchodilation is needed. 2

Preferred Alternative: MDI with Spacer

• A metered-dose inhaler (MDI) with a spacer and face mask is actually the preferred first-line delivery method for infants, offering comparable efficacy to nebulisation while being more convenient and economical. 1, 2
• If the infant tolerates it, give 2 puffs (total 180 µg albuterol) via MDI-spacer-mask every 20 minutes for three doses, which can be repeated up to a cumulative total of 20 puffs in severe cases. 1, 2
• However, many infants cannot tolerate face masks and spacers, in which case nebulisers are necessary. 1

Critical Safety Monitoring

• Observe for signs of deterioration: fatigue, use of accessory muscles, agitation, reduced consciousness, oxygen saturation persistently <90%, or a silent chest. 2
• Monitor for transient hypoxaemia during and immediately after nebulisation, particularly in the first 5–20 minutes, as acidic salbutamol solutions can induce oxygen desaturation in infants. 3
• Maintain oxygen supplementation throughout treatment to keep saturation ≥90%. 1, 2

Adjunctive Systemic Corticosteroid Therapy

• For persistent symptoms or moderate-to-severe exacerbations, add oral prednisolone 2 mg/kg/day for 3 days (maximum 40 mg/day) to improve outcomes. 1, 2
• Alternatively, intravenous hydrocortisone 100 mg six-hourly may be used if oral administration is not feasible. 1

When to Escalate Care

• If maximal inhaled therapy (salbutamol ± ipratropium) does not achieve clinical improvement, initiate an aminophylline infusion (5 mg/kg loading dose over 20 minutes, then 1 mg/kg/hour) and consider transfer to intensive care. 1, 2
• Immediate ICU referral is indicated for cyanosis, silent chest, poor respiratory effort, marked fatigue, reduced consciousness, or inability to maintain oxygen saturation ≥90% despite supplemental oxygen. 1

Common Pitfall to Avoid

• Never use compressed air or room air as the driving gas in hypoxic infants; always employ oxygen at 6–8 L/min to prevent worsening hypoxia during nebulisation. 2
• Do not continue bronchodilator therapy without documented objective improvement (respiratory rate, SpO₂, work of breathing) within 30–60 minutes, as some infants—particularly those with viral bronchiolitis rather than asthma—will not respond. 4