Asthma Attack, Acute

Description

Diagnostic criteria

General and supportive measures

Medicine treatment

Referral

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ICD-10 code: J46

DESCRIPTION

Acute exacerbation of wheezing that is unresponsive to bronchodilator therapy that is usually effective in a child who had been previously diagnosed with asthma.

DIAGNOSTIC CRITERIA

Clinical signs include:

• intense wheezing,
• decreased air entry,
• hyperinflation,
• dyspnoea,
• tachypnoea,
• tachycardia,
• hypoxaemia,
• anxiety,
• restlessness,
• palpable pulsus paradoxus,
• difficulty or inability to talk or feed,
• reduced peak flow rate.

The following are danger signs in acute, severe asthma and require referral:

• restlessness,
• disturbance in level of consciousness,
• PEFR < 60% of predicted value,
• decreasing oxygen saturation < 85%,
• rising P_aCO₂,
• silent chest with auscultation,
• palpable pulsus paradoxus,
• chest pain (air leaks).

Classification of Severity of Acute Asthma Exacerbations

	Mild	Moderate	Severe
Oxygen saturation (performed off oxygen)	> 95%	92–95%	< 92%
PEFR*	70–90%	50–70%	< 50%
Arterial PaCO2	< 35 mmHg < 3.7 kPa	< 40 mmHg < 5.3 kPa	> 40 mmHg > 5.3 kPa
Pulsus paradoxus	< 10 mmHg < 1.3 kPa	10–20 mmHg 1.3–2.7 kPa may be palpable	20–40 mmHg 2.7–5.3 kPa palpable
Wheezing	expiratory	expiratory and inspiratory	breath sounds soft
Respiratory rate	< 40/minute	> 40/minute	> 40/minute
Additional signs		- speaks normally - difficulty with feeding - chest indrawing	- unable to speak - confusion - cyanosis - use of accessory muscles
Management	- Short-acting ß2- agonist, e.g. salbutamol, inhalation PLUS - Prednisone, oral	- Oxygen, - Short-acting ß2- agonist, e.g. salbutamol, inhalation - ± Ipratropium bromide, inhalation - Prednisone, oral	- Oxygen, - Short-acting ß2- agonist, e.g. salbutamol, inhalation stat - Ipratropium bromide, inhalation, - Hydrocortisone, IV If no response: ± MgSO4, IV bolus stat OR ± Salbutamol, IV bolus stat AND Consider ICU care

* Peak expiratory flow rate (PEFR) – as percentage of predicted value.

GENERAL AND SUPPORTIVE MEASURES

• Admit child to a high care unit, if available.
• Monitor:
  • heart rate,
  • blood pressure,
  • respiratory rate,
  • acid-base status,
  • PEFR,
  • blood gases,
  • pulse oximetry.    
• Ensure adequate hydration:
  • Encourage intake of normal maintenance volume of oral fluids, avoid overhydration.
• If unable to drink, give 0.45% sodium chloride/5% dextrose IV.  Patients with prolonged severe asthma may become dehydrated as a result of poor intake or vomiting. It is however inadvisable to overhydrate patients with acute asthma: do not exceed the recommended IV fluid volume in children, i.e. 50 mL/kg/24 hours.
• Monitor potassium levels in a patient on continuous ß₂-agonist.

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Note: Physiotherapy, antihistamines, antibiotics and sedation are not beneficial in the acute setting.
Agitation and restlessness are signs of severe hypoxia.

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MEDICINE TREATMENT

Mild exacerbation of asthma

Bronchodilator, i.e. short-acting ß₂ agonist.

• Salbutamol, inhalation, using a metered-dose inhaler with a spacer device.
  • 200–400 µg (2–4 puffs of 100 µg/puff) repeated every 20–30 minutes depending on clinical response.

OR

• Salbutamol, solution, 0.15–0.3 mg/kg/dose nebulised at 20 minute intervals for 3 doses.
  • Maximum dose: 5 mg/dose.
  • 5 mg salbutamol in 4 mL sodium chloride 0.9% delivered at a flow of 5 L/minute with oxygen.

PLUS

• Prednisone, oral, 1–2 mg /kg, daily immediately up to a maximum of:
  • 20 mg:    Children < 2 years for 5 days.
  • 30 mg:    Children 2–5 years for 5 days.
  • 40 mg:    Children 6–12 years for 5 days.

Moderate or severe asthma

Step 1:
To maintain arterial oxygen saturation > 95%:

• Oxygen, at least 4–6 L/minute by facemask or 1–2 L/minute by nasal cannula.

PLUS

• Short-acting ß₂ agonist:

Severe disease

• Salbutamol, inhalation, using a metered-dose inhaler with a spacer device, 10 puffs (100 µg/puff) = 1 mg per administration, repeated every 20–30 minutes depending on clinical response.

Moderate severity

• Salbutamol, 400–600 µg (4–6 puffs of 100 µg/puff) repeated every 20–30 minutes depending on clinical response.

OR

• Salbutamol, solution, 0.15–0.3 mg/kg/dose nebulised at 20 minute intervals for 3 doses.
  • Maximum dose: 5 mg/dose.
  • 5 mg salbutamol in 4 mL sodium chloride 0.9% delivered at a flow of 5 L/minute with oxygen.

PLUS

• Ipratropium bromide, solution, 0.25 mg, nebulised immediately.
  • If severe, follow with 0.25 mg every 20–30 minutes for 4 doses over 2 hours.
  • Maintenance dose: 0.25 mg 6 hourly.
  • 0.25 mg (2 mL) ipratropium bromide in 2 mL sodium chloride 0.9%.
  • Ipratropium bromide may be mixed with a ß₂-agonist.

PLUS

• Prednisone, oral, 1–2 mg/kg, immediately up to a maximum of:
  • 20 mg: Children < 2 years for 5 days.
  • 30 mg: Children 2–5 years for 5 days.
  • 40 mg: Children 6–12 years for 5 days.

Step 2:
Assess response to treatment in step 1 by using the following table:

	Responder	Non-responder
PEFR	Improvement > 20% OR > 80% (best/predicted)	Improvement < 20% OR < 80% (best/predicted)
Respiratory rate	< 40/minute	> 40/minute
Retraction	absent	present
Speech	normal	impaired
Feeding	normal	impaired

Responder: patient who maintains an adequate response for at least 1 hour.
Non-responder: patient who fails to respond adequately to treatment in step 1.

Proceed to step 3.
Step 3:

Responder:
Review current treatment, possible precipitating or aggravating factors and commence:

• Prednisone, oral, 2 mg/kg as a single daily dose for 5 days.
  • To a maximum of:
    • 20 mg: Children < 2 years for 5 days.
    • 30 mg: Children 2–5 years for 5 days.
    • 40 mg: Children 6–12 years for 5 days.

PLUS

• Short-acting ß₂-agonist:
  • Salbutamol, inhalation, 200 µg (2 puffs of 100 µg/puff) as required using a metered-dose inhaler with a spacer device.

Review maintenance asthma therapy at follow-up.

Non-responder:

Intensify treatment as follows:

Continue

• Short-acting ß₂-agonist:
  • Salbutamol, solution, 0.15–0.3 mg/kg/dose nebulised at 20 minute intervals for 3 doses.
    • Maximum dose: 5 mg/dose.
    • 5 mg salbutamol in 4 mL sodium chloride 0.9% delivered at a flow of 5 L/minute with oxygen.

AND

• Ipratropium bromide, solution, 0.25 mg, nebulised immediately.
  • If severe, follow with 0.25 mg every 20–30 minutes for 4 doses over 2 hours.
  • Maintenance dose: 0.25 mg 6 hourly.
  • 0.25mg (2 mL) ipratropium bromide in 2 mL sodium chloride 0.9%.
  • Ipratropium bromide may be mixed with a ß₂-agonist. 

PLUS
Continue corticosteroid:

• Prednisone, oral, 2 mg/kg as a single daily dose.
  • To a maximum of:
    • 20 mg: Children < 2 years for 5 days.
    • 30 mg: Children 2–5 years for 5 days.
    • 40 mg: Children 6–12 years for 5 days.

OR

• Hydrocortisone, IV, 2 mg/kg/dose 6 hourly.

Consult paediatrician for use of:

• Magnesium sulphate, IV bolus, 25–75 mg/kg administered over 20 minutes.

OR

• Salbutamol, IV, 15 µg/kg as a single dose administered over 10 minutes.

AND

• Need for intensive care.

Step 4: (Assess response to treatment in Step 3.):
If non-responsive, admit to intensive care unit for consideration of:

• Magnesium sulphate, IV bolus, 25–75 mg/kg administered over 20 minutes (if not already given).

AND

• Salbutamol, IV.
  • Loading dose: 15 µg/kg (do not give if stat dose already given).
  • Follow with: 1 µg/kg/minute.
  • If necessary, increase dose by 1 µg/kg every 15 minutes.
  • Maximum dose: 5 µg/kg/minute.
  • Monitor electrolytes and side effects.

No further response
In cases of life threatening asthma in the intensive care unit:

• Aminophylline, IV, 5 mg/kg, loading dose administered over 20–30 minutes. Omit loading dose in children receiving maintenance oral theophylline.
  • Follow with: 1 mg/kg/hour continuous infusion.
  • ECG monitoring is mandatory.

REFERRAL

• Acute exacerbation not responding to treatment.

Click here for the pdf.

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Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Paediatrics, 2023 Edition_Updated November 2025

Chapter 15: Respiratory System,  15.4 Conditions With Predominant Wheeze, 15.4.1 Asthma Attack, Acute