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Acute Asthma Exacerbation vs Poor Control

How to assess asthma severity at the pharmacy counter, when to call 999, when to refer to a GP, and when emergency supply or supply via Patient Group Direction (PGD) is appropriate.

Why this matters

Asthma affects around 5.4 million people in the UK, and community pharmacists regularly encounter patients during both acute exacerbations and periods of worsening day-to-day control. These situations require different responses. A patient with acute severe or life-threatening asthma needs 999 immediately. A patient whose symptoms are deteriorating over days or weeks needs same-day GP review rather than repeated purchases of reliever inhalers.

Key severity markers are peak expiratory flow (PEF), oxygen saturation, visible work of breathing, and the ability to complete a sentence. A silent chest, where there is almost no air entry despite obvious respiratory effort, is a very high-risk sign. In contrast, patients with a mild exacerbation who respond well to salbutamol via a spacer may be managed via emergency supply or supply under a Patient Group Direction (PGD), with clear safety netting, provided follow-up is arranged.

Red flags vs more likely benign

FeatureMore likely benignRed flag ⚠
WheezeAudible, bilateral wheeze without distressSilent chest with minimal air entry despite respiratory effort
PEFAbove 75 percent of best or predictedBelow 50 percent: acute severe. Below 33 percent: life-threatening
SpeechAble to speak in full sentencesUnable to complete sentences in one breath
Oxygen saturation (SpO2)95 percent or above on airBelow 92 percent on air: life-threatening, requires emergency oxygen and 999
Reliever useOccasional use with stable controlUsing reliever more than three times per week: poor control, GP review needed
Night symptomsSleep undisturbedWaking at night more than once a week with wheeze or cough
Response to salbutamolClear improvement within 15 to 20 minutesNo improvement or worsening after 5 to 10 puffs via spacer: call 999
ConsciousnessAlert and orientedConfusion, reduced consciousness or collapse: pre-arrest signs

What to do in pharmacy

Call 999 immediately for any of the following: silent chest with minimal air entry; oxygen saturation below 92 percent on air; PEF below 33 percent of best or predicted; inability to speak in full sentences combined with no response to salbutamol; cyanosis, collapse, reduced consciousness or bradycardia. These are signs of life-threatening or acute severe asthma. If available, give salbutamol 5 mg via nebuliser while awaiting the ambulance. If a nebuliser is not available, give 10 puffs of salbutamol via a spacer. Do not allow the patient to travel to hospital alone.
Arrange same-day GP review or send to Accident and Emergency (A&E) for: PEF between 33 and 50 percent of best or predicted, even if the patient appears settled; PEF between 50 and 75 percent combined with no improvement on the usual reliever; increasing reliever use over the past few days suggesting an escalating exacerbation; a patient who has completed an oral corticosteroid course in the past four weeks. Anyone using their reliever inhaler more than three times per week or waking at night more than once a week has poorly controlled asthma and needs a review of maintenance therapy and an updated asthma action plan.
Emergency supply or supply via a Patient Group Direction (PGD) is appropriate only for a mild exacerbation in a patient with a confirmed asthma diagnosis, where PEF is above 75 percent of best or predicted, the patient can speak in full sentences, and there is a clear response to salbutamol within 15 to 20 minutes. Advise 2 to 4 puffs of salbutamol via a spacer, repeating every 20 minutes in the first hour if needed. A spacer improves lung deposition significantly, so recommend one at every opportunity and check technique. Ensure the patient continues their inhaled corticosteroid as prescribed. Provide safety netting: if symptoms return within 3 to 4 hours, fail to settle, or worsen at any point, the patient should call 999 or attend A&E. Do not supply additional salbutamol inhalers without confirming that GP follow-up has been arranged.

Key takeaways

  • A silent chest in an asthmatic patient is a pre-arrest sign. Call 999 immediately.
  • PEF below 33 percent is life-threatening. PEF between 33 and 50 percent is acute severe. Neither is suitable for emergency supply or pharmacist-managed supply without urgent clinical assessment.
  • Patients using a reliever inhaler more than three times per week have poorly controlled asthma and need GP review and an updated asthma action plan. Do not simply supply additional relievers.

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Professional disclaimer: This article is for educational purposes to support healthcare professionals' clinical decision-making. It does not replace independent professional judgement, local pathways, NICE guidance, or standard medical literature. Members of the public must not use this resource for self-diagnosis and should seek prompt advice from a qualified healthcare professional if experiencing chest pain, palpitations, fainting, or breathlessness.