Conditions with predominant wheeze

• Asthma attack, acute
• Asthma, chronic
• Infrequent asthma
• Persistent asthma

ASTHMA ATTACK, ACUTE

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 PaCO₂ ,
• silent chest with auscultation,
• palpable pulsus paradoxus,
• chest pain (air leaks).

*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.

Note:

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

MEDICINE TREATMENT

Mild and moderate asthma

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

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

OR

• Salbutamol, solution, 0.15–0.3 mg/kg/dose nebulise 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, 100%, at least 4–6 L/minute by facemask or 1–2 L/minute by nasal cannula.

PLUS

• Short-acting ß₂ agonist:
  • Salbutamol, inhalation, using a metered-dose inhaler with a spacer device. Up to 10 puffs (1mg) per administration for severe asthma.
    • 400–600 mcg (4–6 puffs) up to 10 puffs repeated every 20–30 minutes depending on clinical response.

OR

• Salbutamol, solution, 0.15–0.3 mg/kg/dose nebulise 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 (if severe)

• Ipratropium bromide, solution, 0.25 mg, nebulise 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

• 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: 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 7 days.

If oral corticosteroids are not available:

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

PLUS

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

Review maintenance asthma therapy at follow up.

Non-responder:
Intensify treatment as follows:

• Short-acting ß₂ agonist:
  • Salbutamol, solution, 0.15–0.3 mg/kg/dose nebulise 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, nebulise 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.

OR

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

Failure to respond - consult paediatrician

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

OR

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

Consider 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 mcg/kg administered over 20 minutes (if not already given).

AND

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

REFERRAL

• Acute exacerbation not responding to treatment.

ASTHMA, CHRONIC

J45

DESCRIPTION

Asthma is a chronic inflammatory airways disease in which many cells and cellular elements play a role. Susceptible individuals present with recurrent episodes of wheezing, breathlessness, chest tightness and cough particularly in the early morning. There is widespread variable airflow obstruction that is reversible either spontaneously or with treatment. A variety of stimuli, e.g. allergens, viral infections, weather changes, emotional upsets or other irritants precipitate inflammation that is associated with increased bronchial hyper-responsiveness.

DIAGNOSTIC CRITERIA

• Chronic, persistent/recurrent cough and/or wheezing that responds to a bronchodilator.
• Objective evidence of reversible airway obstruction, as measured by > 15% improvement of the peak flow or > 12% improvement in the FEV₁ 20 minutes after administration of an inhaled bronchodilator confirms the diagnosis. (FEV₁ = forced expiratory volume in 1 second).
• A family history of atopy, night or exercise-induced coughing and/or wheezing.

Control of asthma

• The severity of asthma can vary with time and regular reassessments (at least every 3 months) are necessary.
  
  On treatment chronic asthma is classified as:
• controlled,
• partially controlled, or
• uncontrolled.

The following criteria are used to classify control:

Partially controlled or uncontrolled cases requires escalation in therapy while cases controlled for >4 months requires gradual reduction in therapy.

Assessment of severity and classification of chronic asthma

Before initiating treatment, classify the grade of severity of patient illness according to the presence of the most severe feature. This assists in choosing the most appropriate initial maintenance therapy.

Infrequent asthma: less than one acute exacerbation in 4–6 months.
Persistent asthma: mild, moderate or severe.

*Peak expiratory flow rate (PEFR) – patient’s best as percentage of predicted value.

GENERAL AND SUPPORTIVE MEASURES

• Environmental control, avoid triggers, e.g.:
  • exposure to cigarette smoke,
  • preservatives such as sulphites and benzoates,
  • house pets such as cats and dogs,
  • house dust mites sensitisation: use plastic mattress covers, and remove bedroom carpets.
• Wash bedding covers in hot water (>70°C).
• Educate children, parents, caregivers and teachers.

MEDICINE TREATMENT

Medicine delivery systems

Use spacer devices with a metered dose inhaler. Prime all spacers with 2 doses of inhaled medication prior to first use. The size of the spacer is dependent on tidal volume of the child:

The technique of using the spacer varies with age:

• Infants and young children: use tidal breathing of 10 long, deep, slow breaths.
• Older children and adolescents: breathe out fully, actuate the inhaler, then inhale the entire contents in one long slow breath. Hold breath for 10 seconds.

Inhaled corticosteroid use

Inhaled corticosteroids are indicated for all cases of persistent asthma. Spacer devices increase the efficacy of inhaled corticosteroids.
Rinse the mouth after inhalation of inhaled corticosteroids to reduce systemic absorption and adverse effects.
Wash face if a face mask is used.
Use the lowest possible effective dose of steroids.

INFREQUENT ASTHMA

To relieve symptoms:

• ß₂ agonist (short-acting), e.g.:
  • Salbutamol, inhalation, 100–200 mcg, as required 3–4 times daily using a metered-dose inhaler with a spacer device until symptoms are relieved.

Note: Failure to respond to 2 doses of an inhaled bronchodilator given 20 minutes apart is an indication of an acute exacerbation of asthma. See Asthma attack, acute.

PERSISTENT ASTHMA

Mild persistent asthma

When needed for acute exacerbations:

• ß₂ agonist (short-acting), e.g.:
  • Salbutamol, inhalation, 100–200 mcg, as required 3–4 times daily using a metered-dose inhaler with a spacer device until symptoms are relieved.

PLUS

Low dose inhaled corticosteroids, e.g.:

• Beclomethasone or budesonide, inhalation, 50–100 mcg, 12 hourly using a metered-dose inhaler with a spacer device.

Moderate persistent asthma

To relieve symptoms:

• ß₂ agonist (short-acting), e.g.:
  • Salbutamol, inhalation, 100–200 mcg, as required 3–4 times daily using a metered-dose inhaler with a spacer device until symptoms are relieved.

PLUS

Low dose inhaled corticosteroids, e.g.:

• Beclomethasone or budesonide, inhalation, 50–100 mcg, 12 hourly using a metered-dose inhaler with a spacer device.

Moderate persistent asthma

To relieve symptoms:

• ß₂ agonist (short-acting), e.g.:
  • Salbutamol, inhalation, 100–200 mcg, as required 3–4 times daily using a metered-dose inhaler with a spacer device until symptoms are relieved.

PLUS

Regular anti-inflammatory treatment with medium-dose inhaled corticosteroids:

• Beclomethasone or budesonide, inhalation, 100–200 mcg, 12 hourly using a metered-dose inhaler with a spacer device.

OR

In children > 6 years with multiple allergies on other steroid formulations, low-dose inhaled corticosteroids plus long-acting beta agonist (LABA) e.g.:

• Fluticasone plus salmeterol by inhalation, 12 hourly.
  Specialist initiated.
• Metered dose inhaler:
  • Fluticasone/salmeterol, 25/50 MDI, 2 puffs 12 hourly.
  • OR
  • Fluticasone/salmeterol 25/125 MDI, 2 puffs, 12 hourly.
  • OR
  • Accuhaler:
  • Fluticasone/salmeterol 50/100, 1 inhalation, 12 hourly.
  • OR
  • Fluticasone/salmeterol 50/250, 1 inhalation, 12 hourly.

Severe persistent asthma

To relieve symptoms:

• ß₂ agonist (short-acting), e.g.:
  • Salbutamol, inhalation, 100–200 mcg, as required 3–4 times daily using a metered-dose inhaler with a spacer device until symptoms are relieved.

PLUS

Low-dose inhaled corticosteroids plus LABA, e.g.:

• Fluticasone plus salmeterol, inhaled, 12 hourly. Specialist Initiated.
• Metered dose inhaler:
  • Fluticasone/salmeterol, 25/50 MDI, 2 puffs 12 hourly.
  • OR
  • Fluticasone/salmeterol 25/125 MDI, 2 puffs, 12 hourly.
  • OR
  • Accuhaler:
  • Fluticasone/salmeterol 50/100, 1 inhalation, 12 hourly.
  • OR
  • Fluticasone/salmeterol 50/250, 1 inhalation, 12 hourly.

REFERRAL

• Diagnostic uncertainty.
• After a life-threatening episode.
• Unstable or difficult to control asthma.
• Asthma interfering with normal life, despite treatment.
• Severe persistent asthma not responding to therapy.

Suggested reference peak expiratory flow (PEF) values for children:

For optimal control 80% of the predicted peak flow is required.