1
Acute Severe Asthma
Communication is key – ensure Consultant Paediatrician, Anaesthetist and
PICU all involved.
Assessment
Acute Severe
Can’t complete sentences in one
breath or too breathless to feed
CVS
Pulse
>120 in age >5 yrs
>130 in age 2-5 yrs
Respiratory
Rate
>30/min age >5yrs
>50/min age 2-5 yrs
PEFR*
<50% best
Saturations
<92% in room air
CNS
Life Threatening
Silent chest
Cyanosis
Exhaustion
Hypotension
Poor respiratory effort
<33% best
<92% in high flow oxygen
Confusion
Coma
Exclude: pneumothorax, collapsed lobe, foreign body, upper airway obstruction or
pneumonia. Perform chest x-ray.
Initial Management
1. Oxygen. Aim for SpO2 ≥92% with either tight fitting face mask or nasal canulae.
2. Nebulisers. ‘Back to back’ salbutamol (2.5-5mg) and ipratropium 250mcg (125
mcg if < 2yrs).
3. Steroids. Give early as benefits usually take 3-4 hours. Hydrocortisone
4mg/kg.
4. IV Salbutamol. 15mcg/kg over 15 mins (max 250 mcg), subsequent infusion of
1-2mcg/kg/min. Beware of side effects: lactic acidosis, tachycardia,
hypokalaemia, hyperglycaemia & arrhythmias. Need continuous ECG monitoring.
5. IV aminophylline. 5mg/kg loading (NOT if on oral theophylline) followed by
infusion of 1mg/kg/hour (>12 yrs 0.5-0.7 mg/kg/hr).
6. Magnesium sulphate. 40-50mg/kg over 30 minutes. Hypotension most
common side effect.
Ver.1. Nov 2014
2
Intubation
Indications
 Tired
 Reduced level of consciousness
 Worsening hypoxaemia
N.B. Laboratory investigations are less important than clinical picture
Practicalities
 Most experienced person available should perform
 Pre-oxygenate
 Have 10-20mls/kg of fluid attached and ready to go. Consider
administering a fluid bolus pre-emptively.
 Use a cuffed ETT as high airway pressures are likely to be required.
 Ketamine is a useful induction agent (1-2mg/kg) due to its
bronchodilator activity.
 Sevoflurane also has bronchodilator activity therefore useful for
maintenance.
 Avoid morphine & atracurium (histamine release).
Ventilation
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Sedate & paralyse. Sevoflurane can be used or infusion of midazolam
and fentanyl. Vecuronium can be used for paralysis.
Avoid peak inspiratory pressure > 35 cmH2O.
Permissive hypercapnea to keep pH ≥7.2.
Ensure long enough expiratory time to avoid gas trapping – i.e. low rate
(10—15 breaths/min), I:E ratio of at least 1:2.
PEEP. A PEEP of 5-7cmH2O often necessary to overcome intrinsic PEEP
and prevent gas-trapping.
Regular suction to prevent mucus plugging.
Check CXR for ETT position (between clavicles).
Beware of auto-PEEP. Disconnect from ventilator if suspected and
consider manual decompression.
Beware of pneumothorax.
Acute bronchospasm can be relieved by adrenaline (O.1mg/kg = 0.1ml/kg
of 1:10,000 solution).
Cardiovascular
Commonest complication is hypotension caused by high intrathoracic pressure
limiting venous return. Use 10-20ml/kg alloquats of iv fluid as required.
Ver.1. Nov 2014