• Acute asthma can be life-threatening and requires appropriate assessment + management

• Involve ITU if rising pCO2 or tiring patient

• Regular inhalers and medications should be continued where possible

• Asthma in pregnancy should be treated in the same way as if the patient were not pregnant for the best outcome for mother and foetus

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Abbreviations

Acute reversible airways obstruction. Healthcare professionals must be aware that patients with severe asthma and one or more adverse psychosocial factor(s) are at risk of death.

Life threatening features:

• PEF <33% of predicted normal or best

• Silent chest

• Cyanosis

• Poor respiratory effort

• Arrythmia

• Hypotension

• Exhaustion, confusion, or reduced conscious level

• Blood gas features of a life-threatening attack:

CO2 4.6-6 kPA (normal) or high arterial retention PaO2 <8 kPA- Severe hypoxaemia irrespective of treatment with oxygen SpO2 <92% Low pH value (irrespective of PaO2)

Investigations:

• ABG

• No other investigations are needed for immediate management.

• Patients with severe or life-threatening attacks may not be distressed and may not have all these abnormalities. The presence of any should alert the doctor and prompt ITU review.

Urgent ITU discussion if any of the following:

• Inability to complete sentences in one breath
• RR > 25 breaths/min
• HR > 110bpm
• PEF 33-50% of predicted normal or best

Investigations:

• Blood tests: FBC (Hb, WCC), U&Es, CRP, theophylline level (if already on).
• ABG if O₂ saturation <95% or any features of severe asthma.
• Chest X-ray: if pneumothorax or consolidation is suspected, if the patient requires mechanical ventilation or the patient fails to respond to treatment satisfactorily.
• Peak expiratory flow rate (PEFR).

• Oxygen - High concentration. Give to all patients with acute severe asthma to maintain SpO2 94-98%. Lack of pulse oximetry should not prevent the use of oxygen.

• Salbutamol 5mg for initial dose, then 2.5mg thereafter via an oxygen-driven nebuliser. Administer as early as possible and give back to back nebulisers if required. Reserve intravenous beta2 agonists for those patients in whom inhaled therapy cannot be used reliably.

• Prednisolone 40-50 mg OM orally for at least 5 days, continued until recovery. If unable to swallow then prescribe hydrocortisone 100mg IV QDS.

• Give steroids in all cases of acute asthma attack.

• Ipratropium bromide 500mcg 4-6 hourly via an oxygen-driven nebuliser. Can be used in conjunction with salbutamol and should be used in patients with acute-severe or life-threatening asthma or those with a poor initial response to B2¬ agonist therapy. Hold LAMA-containing inhalers whilst on these.

• Do not prescribe sedatives of any kind.

• Antibiotics if patient is pyrexial or CXR consolidation (refer to Antimicrobials guidance).

• VTE prophylaxis as per Trust guidelines.

• Consider IV hydration as tachypnoea can lead to dehydration.

• Correct electrolyte abnormalities. Regular Salbutamol use will lower K+.

• Discuss with senior clinician and ITU team.

• Treat as above.

• Increase frequency of nebulised B2 agonist, e.g. salbutamol 5mg up to every 15-30 minutes.

• After discussion with senior medical staff, consider IV magnesium sulphate 1.2-2g infusion over 20 minutes. May be of use in patients with acute severe asthma (PEF <50% best or predicted) who have not had a good initial response to inhaled bronchodilator therapy. Nebulised magnesium is not recommended for treatment in adults with acute asthma. Further doses are not recommended as no evidence for this and repeated doses could cause hypermagnesaemia with muscle weakness and respiratory fatigue.

• Requiring ventilator support.
• With acute severe or life-threatening asthma, who is failing to respond to therapy, as evidenced by:
  • Deteriorating PEF
  • Persisting or worsening hypoxia
  • Hypercapnia
  • ABG analysis showing ↓ pH or ↑ H⁺.
  • Exhaustion, feeble respiration
  • Drowsiness, confusion, altered conscious state
  • Respiratory arrest

If patient is improving:

• Oxygen to maintain SpO₂ 94-98%
• Prednisolone 40-50 mg OM or IV hydrocortisone 100mg 6 hourly.
• Nebulised B2 agonist and ipratropium 4-6 hourly.
• Continue regular ICS inhalers given via spacer if required.

• Continue oxygen and steroids.
• Salbutamol 2.5-5mg every 15-30 minutes via nebuliser.
• Ipratropium 0.5mg 4-6 hourly until patient shows improvement.

• Discuss with senior clinician and ITU team.

• Consider IV magnesium sulphate 1.2-2g infusion over 20 minutes (unless already given).

• Under senior clinician decision; Consider IV aminophylline: Load with 250-500mg (5mg/kg) over 20 minutes (check patient not taking oral theophylline / aminophylline.

Do not load aminophylline dose if a patient is on oral theophylline or aminophylline.

Then give 500 micrograms/kg/hour by continuous IV infusion over 24 hours based on ideal body weight. Check levels if infusion continues (4-6 hours after start, repeat 12-18 hours then daily– mark urgent). Therapeutic range = 6-20 mg/L.

• Senior clinician may consider progression to mechanical ventilation.

• Patient will require Level 2 care on ITU or MADU, AMU Green on a cardiac monitor with low threshold for ITU support,

• Deteriorating PEF, worsening or persisting hypoxia, or hypercapnia
• Exhaustion, altered consciousness
• Poor respiratory effort or respiratory arrest

• Start PEFR chart: measurements before and after giving B2 agonist and at least 4 times daily throughout hospital stay.

• Oxygen: continued on ward if O2 saturations low, maintain SpO2 >94-98%.

• Oxygen saturations SaO2: measured at hourly intervals by nurse for 12 hours and nursing staff must notify medical staff if O2 saturation falls below 95%.

• Ensure patient receives inhaled steroids or combination steroids and LABA (step up from their previous maintenance).

• Review / correct inhaler technique.

• Smoking cessation / allergen avoidance advice. Consider allergen testing, total IgE if not previously done.

Refer to respiratory nurse, who will be able to ensure inhaler technique correct, review their asthma care plan and review criteria for discharge and follow up with the patient. However, do not delay discharge if referral is not possible.

• Off nebulised drugs and on discharged medication for 12-24 hours.

• Counselled on inhaler technique.

• PEF >75% predicted or best with a variability of <25% unless discharge is agreed with respiratory clinician.

• Treatment with oral and inhaled steroids and LABA combination inhalers, patient on ICS/LABA should be on them as a maintenance and reliever therapy (MART).

• See MART plans for the different ICS/LABA combinations available in the trust on the Frimley ICB respiratory page https://www.frimley.icb.nhs.uk

• Discuss asthma self-management plan.

• Own PEF meter.

• Arrange GP review 2 days post discharge.

• Referral to respiratory clinic for follow-up within 4 weeks.

• It is essential that the patient’s primary care practice is informed within 24 hours of discharge from the emergency department or hospital following an asthma attack.

• Keep patients who have had a near-fatal asthma attack under specialist supervision indefinitely.

• A respiratory specialist should follow up patients admitted with a severe asthma attach for at least one year after the admission.

The natural history of asthma during pregnancy is extremely variable. The conclusions of a meta-analysis of 14 studies is in agreement with the commonly quoted generalisation that during pregnancy about one third of asthma patients experience an improvement in their asthma, one third experience a worsening of symptoms, and one third remain the same, There is also some evidence that the course of asthma is similar in successive pregnancies. A systematic review showed no effect of pregnancy or stage of pregnancy on FEV1.

Patients should be treated in exactly the same way as non-pregnant asthmatics and should be reassured that all usual chronic and acute medications are safe in pregnancy. Maintaining good asthma control is the safest pathway for both mother and baby.

This guideline has been registered with the Trust. However, clinical guidelines are guidelines only. The interpretation and application of clinical guidelines will remain the responsibility of the individual clinician. If in doubt, contact a senior colleague or expert. Caution is advised when using guidelines after the review date. This guideline is for use in Frimley Health NHS Foundation Trust hospitals only. Any use outside this location will not be supported by the Trust and will be at the risk of the individual using it.

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