Asthma

• Clinical Investigations

  • ABG
  • Chest X-ray changes
  • Altered breath sounds on auscultation
  • Wheeze during expiration / inspiratory
  • Reduced breath sounds
  • Alteration lung function tests
  • FEV1 : FVC ratio
  • Flow volume loops
• Lung Function Tests:

  • shows if someone has an obstructive disease
  • uses FEV1 / FVC ratio
  • <75 % predicted mild impairment
  • < 60 % moderate impairment
  • less than 40% severe impairment
• Peak flow metre:

  • the wider the airways, the more air that can be blown into it

  
• Status Asthmaticus:

  • Unresponsive to therapy
  • peak expiration flow rate is less than 50% predicted normal or best
  • respiratory rate is more than 25 breaths / min
  • heart rate is more than 110 beats / min
  • PaO2 is less than 8 kPa
  • No breath sounds on auscultation
  • Interrupted speech
• Indications for ventilation:

  • Exhaustion of the patient
  • PaO2 is less than 6.5 kPa & falling
  • PaCO2 more than 6.7 kPa & rising
  • Hypotension (systolic blood pressure is less than 90 mm Hg)
  • Respiratory & or cardiac arrest
• Brittle Asthma:

  • Relatively rare
  • Characterised by chaotic variation in peak expiration flow rate
  • Little stability daily
  • Management difficult
  • rapidity of onsets of attacks though they can be quick to resolve
  • patients may carry injections of adrenaline