A 65 year old woman with chronic airways disease presents with acute respiratory failure.

Outline how you would determine the severity of her underlying airways disease.

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College Answer

History: consider – exercise tolerance; ADLs; home O2 use; home CPAP/NIV use; respiratory medication use and compliance; steroid use; need for heart failure medication; frequency of hospitalisations or previous mechanical ventilation.

Examination: consider – steroid skin; cachexia / nutritional assessment; plethora secondary to polycythaemia.

Investigations:  consider – previous ABGs (degree of hypoxaemia/hypercapnoea/metabolic compensation); Electrolytes: especially tCO2 indicative of bicarbonate compensation of chronic hypercapnoea; previous spirometry (FEV1/FVC - degree of emphysema/hyperexpansion/evidence of left or right heart failure); formal Pulmonary Function Tests (DLCO/flow-vol loops); ECG (?chronic right heart strain pattern); Hb (polycythaemia secondary to chronic hypoxaemia).

Discussion

This question asks about the assessment of the severity of COPD.

Historical features

  • exercise tolerance
  • breathlessness with everyday activities
  • presence of chronic cough
  • high volume of sputum, suggestive of bronchiectasis
  • haemoptysis, suggestive of malignancy
  • home O2 requirement
  • home CPAP requirement
  • pattern of bronchodilator use
  • pattern of steroid use
  • frequency of hospitalisations
  • previous mechanical ventilation
  • anorexia and weight loss

Examination

  • features of malnutrition
  • features of obesity (sedentary lifestyle)
  • features of chronic steroid use
  • central cyanosis
  • breathlessness at rest
  • hyperexpanded chest
  • degree of air entry
  • signs of right heart failure

Investigations

  • Bicarbonate levels
  • Hb (polycythaemia)
  • Spirometry, pre and post bronchodilator
  • Formal lung function tests
  • ABGs to determine degree of hypoxia and hypercapnea
  • TTE (pulmonary pressures)
  • High-resolution CT to assess the severity of emphysematous changes

References

Siafakas, N. M., et al. "Optimal assessment and management of chronic obstructive pulmonary disease (COPD)." European Respiratory Journal 8.8 (1995): 1398-1420.