This document provides guidelines for the management of acute severe asthma. Initial assessment involves measuring peak expiratory flow, vital signs, and arterial blood gases. Treatment includes high doses of inhaled bronchodilators, systemic corticosteroids, oxygen, intravenous fluids and magnesium. Mechanical ventilation may be required if the patient deteriorates or is unable to be adequately ventilated. Close monitoring of peak expiratory flow, oxygen saturation, and serum aminophylline levels is important.

1. MANAGEMENT OF ACUTE
SEVERE ASTHMA

2. Introduction
• A life-threatening exacerbation of asthma
symptoms
• Findings:
PEF (peak expiratory flow) 33-50% predicted (< 200 l/min)
Respiratory rate ≥ 25/min
Heart rate ≥ 110/min
Arterial blood gas analysis PaO2 (N: 75-105 mm Hg)and
PaCO2 (N: 35-45 mm Hg)
Inability to complete sentences in 1 breath

3. Management
• Initial assessment
• Treatment
• Mechanical ventilation
• Monitoring

4. Initial assessment
Immediate assessment of
ability to speak
Vital signs
Measurement of PEF is mandatory unless the
patient is too ill to cooperate
Arterial blood gas analysis

5. Treatment
• Oxygen
• High doses of inhaled bronchodilators
• Systemic corticosteroids
• Intravenous fluids
• Subsequent management

6. Treatment contd…
• Oxygen
– High concentrations of oxygen (humidified if
possible)
– Goal: SaO2 > 92%
– Failure to achieve appropriate oxygenation
 assisted ventilation.

7. Treatment contd…
• High doses of inhaled bronchodilators
– Short-acting β2-agonists (Salbutamol 5mg/hr)
• via nebuliser driven by oxygen or via a metered
dose inhaler through a spacer device
– An inhaled anticholinergics (Ipratropium bromide
µg) may be added

8. Treatment contd…
• Systemic corticosteroids
– intravenous hydrocortisone 200 mg : in patients
who are unable to swallow or vomiting.
– Oral prednisolone 0 mg

9. Treatment contd…
• Intravenous fluids
– To correct dehydration and acidosis
– Normal saline + sodium bicarbonate/lactate
infusion
– Potassium supplements to treat hypokalemia
induced by Salbutamol

10. Treatment contd…
• Subsequent management
– If patients fail to improve
• Intravenous magnesium sulphate(1.2–2 g over 20
min)
• Intravenous β2 agonists(e.g. Salbutamol)
• Intravenous aminophylline (5mg/kg loading dose
over 20 minutes followed by continuous infusion at
mg/kg/hr )
• Intravenous leukotriene receptor antagonists
• Anaesthetics (e.g. halothane)

11. Mechanical Ventilation
• Initial goals
– To correct hypoxaemia
– To achieve adequate alveolar ventillation
– To minimize circulatory collapse
– To buy time for medical management to work
• Indications
– Coma
– Respiratory arrest
– Deterioration of arterial blood gas tensions despite
optimal therapy
– Exhaustion, confusion, drowsiness

12. Monitoring of treatment
• PEF should be recorded every 15-30 minutes
• Pulse oximetry should ensure that SaO2 remains >
92%
• If aminophylline is given, then monitor the serum
concentration (therapeutic range 10–20 µg ml
• Repeat arterial blood gases if
– initial PaCO2 measurement was raised
– PaO2 was < 8 kPa (60 mmHg) or
– the patient deteriorates.