Recognition of acute asthma

Definitions of increasing levels of severity of acute asthma attacks are provided in the table below. Predicted PEF values should be used only if the recent best PEF (within two years) is unknown.

Self treatment by patients developing acute or uncontrolled asthma

Patients with asthma, and all patients with severe asthma, should have an agreed written PAAP and their own peak-flow meter, with regular checks of inhaler technique and adherence. They should know when and how to increase their medication and when to seek medical assistance. Written PAAPs can decrease hospitalisation for,¹⁶⁶ and deaths from asthma (see the section on self-management).⁵⁷³

Initial assessment 

All possible initial contact personnel, for example practice receptionists, ambulance call takers, NHS 111 (England and Wales), NHS 24 (Scotland), and out-of-hours providers, should be aware that asthma patients complaining of respiratory symptoms are at risk of becoming seriously unwell very quickly. Such patients
should have immediate access to a healthcare professional trained in the emergency treatment of asthma. The assessments required to determine whether the patient is suffering from an acute attack of asthma, the severity of the attack and the nature of treatment required are detailed in the tables below. It may be helpful to use a systematic recording process. Proformas have proved useful in the ED setting.⁵⁷⁴

Levels of severity of acute asthma attacks in adults

Prevention of acute deterioration

A register of patients at risk may help healthcare professionals in primary care to identify patients who are more likely to die from their asthma. A system should be in place to ensure that these patients are contacted if they fail to attend for follow up.

Other factors, such as failure to respond to treatment, social circumstances or concomitant disease, may warrant hospital referral.

Initial assessment of symptoms, signs and measurements

Adult patients with any feature of a life-threatening or near-fatal asthma attack or a severe asthma attack that does not resolve after initial treatment should be admitted to hospital. Admission may also be appropriate when peak flow has improved to greater than 75% best or predicted one hour after initial treatment but concerns remain about symptoms, previous history or psychosocial issues (see Lessons from asthma deaths and near-fatal asthma).⁵⁵⁶, ⁵⁵⁸, ^566-571

Many deaths from asthma are preventable. Delay can be fatal. Factors leading to poor outcome include:

• Clinical staff failing to assess severity by objective measurement
• Patients or relatives failing to appreciate severity
• Under use of corticosteroids

Regard each emergency asthma consultation as for acute severe asthma until shown otherwise

Assess and record:

• Peak expiratory flow (PEF)
• Symptoms and response to self treatment
• Heart and respiratory rates
• Oxygen saturation (by pulse oximetry)

Caution: Patients with severe or life-threatening attacks may not be distressed and may not have all the abnormalities listed below. The presence of any should alert the doctor.

Initial assessment

• PEF>50–75% best or predicted - moderate asthma
• PEF 33–50% best or predicted - acute severe asthma
• PEF<33% best or predicted - life-threatening asthma

Further assessment

Moderate asthma:

• SpO₂ ≥92%
• Speech normal
• Respiration <25 breaths/min
• Pulse <110 beats/min.

Acute severe asthma:

• SpO₂ ≥92%
• Can’t complete sentences
• Respiration ≥25 breaths/min
• Pulse ≥110 beats/min.

Life-threatening asthma:

• SpO₂ <92%
• Silent chest, cyanosis or poor respiratory effort
• Arrhythmia or hypotension
• Exhaustion, altered consciousness.

Management and Treatment

Moderate asthma:

Treat at home or in surgery and assess response to treatment.

• β₂ bronchodilator:
  • via spacer*
• If no improvement:
  • via nebuliser (preferably oxygen-driven), salbutamol 5 mg
• Give prednisolone 40–50 mg
• Continue or increase usual treatment
• If good response to first treatment (symptoms improved, respiration and pulse settling and PEF >50%) continue or increase usual treatment and continue prednisolone.

Admit to hospital if any:

• Life-threatening features
• Features of acute severe asthma present after initial treatment
• Previous near-fatal asthma

Lower threshold for admission if afternoon or evening attack, recent nocturnal symptoms or hospital
admission, previous severe attacks, patient unable to assess own condition, or concern over social circumstances.

Acute Severe asthma:

Consider admission.

• Oxygen to maintain SpO₂ 94–98% if available
• β₂ bronchodilator:
  • via nebuliser (preferably oxygen-driven), salbutamol 5 mg
  • or if nebuliser not available, via spacer*
• Prednisolone 40–50 mg or IV hydrocortisone 100 mg
• If no response in acute severe asthma: ADMIT.

If admitting the patient to hospital:

• Stay with patient until ambulance arrives
• Send written assessment and referral details to hospital
• β₂ bronchodilator via oxygen-driven nebuliser in ambulance.

Life-threatening asthma:

Arrange immediate admission.

• Oxygen to maintain SpO₂ 94–98%
• β₂ bronchodilator with ipratropium:
  • via nebuliser (preferably oxygen-driven), salbutamol 5 mg and
    ipratropium 0.5mg
  • or if nebuliser and ipratropium not available, β₂ bronchodilator via spacer*
• Prednisolone 40–50 mg or IV hydrocortisone 100 mg immediately.

Follow up after treatment or discharge from hospital:

• Continue prednisolone until recovery (minimum 5 days)
• GP review within 2 working days
• Monitor symptoms and PEF
• Check inhaler technique
• Written asthma action plan
• Modify treatment according to guidelines for chronic persistent asthma
• Address potentially preventable contributors to admission.

* β₂ bronchodilator via spacer given one puff at a time, inhaled separately using tidal breathing; according to response, give another puff every 60 seconds up to a maximum of 10 puffs

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