Makindo Medical Notes

Related Subjects: Asthma |Acute Severe Asthma |Exacerbation COPD |Pulmonary Embolism |Cardiogenic Pulmonary Oedema |Pneumothorax |Tension Pneumothorax |Respiratory (Chest) infections Pneumonia |Fat embolism |Hyperventilation Syndrome |ARDS |Respiratory Failure |Diabetic Ketoacidosis

Prevention is key and all patients at risk of severe exacerbations should have an individualised plan to manage any exacerbation early with Short-acting beta-agonists and oral steroids and seeking medical help.

Note: The fixed combination of an inhaled glucocorticoid and a LABA improves lung function, reduces the frequency and severity of exacerbations, and enhances the quality of life in patients with asthma.

About

• Asthma is a chronic disease characterized by intermittent reversible airway obstruction.
• The incidence appears to be increasing, but this is balanced by better management and access to inhaled steroids.
• Patients with acute severe asthma can suddenly deteriorate, so they should not be left unobserved by healthcare staff, even during procedures like imaging.
• Typical asthma symptoms include wheeze, shortness of breath, chest tightness, and cough.

Basics

• Ensure the patient is sitting up, supported, and as comfortable as possible. Reassurance and hydration are key, as well as encouraging slower and deeper respirations.
• A positive, confident, and competent attitude from staff can help greatly. The patient may be terrified and working hard to breathe, especially in severe cases.
• Monitor the patient closely in a well-staffed area with continuous ECG and O₂ saturation monitoring.
• Patients must be observed at all times, including during transfers (e.g., for chest X-ray) as rapid and sudden deterioration or cardiac arrest is possible.

Assessing Severity

• Acute Severe:
  • SpO₂ > 92%
  • PEF 33-50% of predicted or PEF < 200 L/min
  • Respiratory rate > 25/min
  • Heart rate > 110/min
  • Unable to complete sentences in one breath
• Life-threatening:
  • PEF < 33% of predicted or SpO₂ < 92%
  • ABG: PaO₂ < 8 kPa (60 mmHg) or normal/raised PaCO₂
  • Signs: Silent chest, cyanosis, feeble respiratory effort, exhaustion
  • Hypotension, bradycardia/arrhythmias
  • Confusion or coma
• Near-fatal Asthma:
  • Raised PaCO₂
  • Need for intubation and mechanical ventilation
• Discharge Criteria:
  • Symptoms, particularly nocturnal symptoms, have improved
  • PEFR is ≥ 75% of best with diurnal variation < 25%
  • Good expected compliance
  • Home on inhaled steroids + oral corticosteroids
  • Management plan for deterioration established

Chest X-ray Indications

• Not routinely recommended unless:
• Suspected pneumomediastinum
• Suspected pneumothorax
• Suspected consolidation
• Life-threatening asthma
• Failure to respond to treatment
• Requirement for ventilation

Management if PEFR < 50% and Signs of Acute Severe Asthma

• Admit the patient. Follow ABC protocol, start high-flow oxygen, and take senior advice. Consider ICU review if not responding within 15-20 minutes.
• Provide high-flow oxygen at 15 L/min to maintain target saturations of 92-94%. Use high-flow oxygen to drive nebulizers.
• Administer IV fluids to prevent dehydration, adding potassium if needed as salbutamol can lower serum potassium levels.
• Give IV antibiotics only if there is clear evidence of bacterial infection.
• Nebulized Salbutamol 5 mg every 15-20 minutes initially, then 1-2 hourly. Alternatively, use Terbutaline 5-10 mg via nebulizers.
• Nebulized Ipratropium Bromide 500 mcg (0.5 mg) every 4-6 hours, given with Salbutamol.
• Start Prednisolone 40-60 mg orally or Hydrocortisone 200 mg IV stat, followed by 100 mg IV every 6 hours or oral Prednisolone for at least 5 days.
• Avoid routine chest X-rays, blood gases, or antibiotics unless clearly indicated.

Management: PEFR > 50% and No Signs of Acute Severe Asthma

• No features of acute severe asthma.
• Give up to 10 puffs of Salbutamol via a volumatic spacer device.
• Give Prednisolone 40 mg orally.
• Good Response: PEFR > 75% in 1 hour. Continue Prednisolone 40-50 mg for 5 days. Ensure correct inhaler technique, prescribe inhaled corticosteroids (at least 400 mcg). Discharge home if stable.
• Partial Response: PEFR < 75% in 1 hour. Consider nebulized Salbutamol and IV magnesium. Continue Prednisolone 40 mg daily for 5 days. Admit if not improving. Seek senior advice if needed.

Further Management for Non-Responding Patients

• Administer Magnesium Sulphate 1.2-2.0 g (8 mmol) IV over 20 minutes for bronchodilation.
• Consider Aminophylline:
  • Loading dose of 5 mg/kg IV over 20 minutes unless the patient is on oral theophylline.
  • Maintenance dose of 0.5 mg/kg/hr with ECG monitoring.
  • Aim for plasma concentrations of 10-20 mcg/mL (55-110 umol/L). Monitor for toxicity at levels >25 mcg/mL.
• Use Adrenaline 0.5 mg IM for bronchospasm as part of anaphylaxis (e.g., from allergens).
• Consider IV Salbutamol infusion at 5-20 mcg/min. Monitor for lactic acidosis, which can develop in 70% of patients within 2-4 hours.
• Intubation Criteria:
  • Progressive exhaustion, drowsiness, or altered mental state.
  • Respiratory arrest.
  • PaO₂ < 8 kPa (60 mmHg) despite 60% oxygen.
  • PaCO₂ > 6 kPa (45 mmHg) with worsening acidosis.
  • Early involvement of ICU for potential intubation and mechanical ventilation is critical.

Discharge Planning

• Ensure inhaler technique is correct and the patient has a preventer medication.
• Continue oral Prednisolone for 5-10 days.
• Review asthma maintenance treatment and provide smoking cessation advice.
• Stop nebulizers 24 hours before discharge.
• Provide a written, agreed action plan and ensure the patient has a PEF meter and diary.
• Arrange follow-up with GP, asthma nurse, or respiratory clinic within 4 weeks.

References

• Global Initiative for Asthma (GINA) Guidelines 2019
• Holguin F, Cardet JC, Chung KF, et al. Management of Severe Asthma: a European Respiratory Society/American Thoracic Society Guideline. Eur Respir J 2019