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Chronic Obstructive Pulmonary Disease

From Mediwikis
Chest X Ray of a patient with COPD

This disease is important to differentiate from Asthma, being a progressive, non reversible bronchoconstriction affecting the small airways and parenchyma. Destruction of the aveoli occurs (emphysema). While the damage is irreversible, symptoms can be treated. COPD has an older onset than asthma, and is strongly (90%) associated with smoking.

Signs & Symptoms

  • Chronic, progressive shortness of breath, often worse on exercise (while patient may have good and bad days, overall disease trajectory is downwards)
    • Exacerbating factors:
      • Extremes of temperature
      • Infection.
  • Chronic productive cough- greater than 3 months without obvious cause = chronic bronchitis
  • Cor Pulmonale in later stages- Swollen ankles and added dyspnoea.
  • Hyperinflated lungs "Barrel Chest"

Investigations

  • Chest X-Ray
    • Hyperinflation
    • Flattened Hemidiaphragms
    • Dilated pulmonary arteries
  • O2 Sats may be "normal low" 88-92%
  • Full Blood Count- May show Polycythaemia (Raised Haematocrit)
  • ABG shows reduced oxygen, and possibly Respiratory Acidosis
  • Spirometry in the long term environment, to delineate from restrictive lung disease, and measure disease progress.
    • FEV1/FVC < 70% means obstructive picture
    • Severity of COPD is judged by %FEV1 of a normal healthy person of that age
    • Oral Steroid trial- 30 mg Prednisalone for 2 weeks. If FEV1 rises by>15%, COPD is steroid responsive.

Treatment

  • Refer to Pulmonary Rehabilitation Team
  • Offer smoking cessation advice

Inhalers

Breathlessness and exercise limitation

  • Short Acting β-2 Agonist (SABA) PRN or Short Acting Muscarinic Antagonist (SAMA) PRN

Exacerbations/ Persistent breathlessness

  • Long Acting β-2 Agonist ± Inhaled Steroid OR
  • Long Acting Muscarinic Antagonist

Persistent Exacerbations or breathlessness[1]

  • Long Acting β-2 Agonist ± Inhaled Steroid AND
  • Add in Long Acting Muscarinic Antagonist

Drugs and Common Brand Names:

  • SABA=Salbutamol or Terbutaline
  • LABA=Salmeterol
  • SAMA=Ipratropium Bromide
  • LAMA=Tiotropium
  • LABA+Inhaled Steroid= Seretide (salmeterol+fluticasone)

Oxygen Therapy

Normally, respiratory drive is determined mainly by the level of CO2 in the blood- more=increased need to breathe. Certain patients with chronically compensated CO2 levels (CO2 retainers) instead use hypoxia to drive their respiration. Placing these patients on high flow oxygen may therefore lead to reduced breathing, so perform ABGs regularly after starting O2 therapy. Long term, Oxygen therapy improves a patients life expectancy, but has no significant effect on their quality of life The criteria for home oxygen include: PEFR <30% predicted, O2 sats less than 92% on AIR, cyanosis, peripheral oedema, raised JVP, polycythaemia.

References

  1. Rojas-Reyes MX, García Morales OM, Dennis RJ, Karner C. Combination inhaled steroid and long-acting beta2-agonist in addition to tiotropium versus tiotropium or combination alone for chronic obstructive pulmonary disease. Cochrane Database of Systematic Reviews 2016, Issue 6. Art. No.: CD008532. DOI: 10.1002/14651858.CD008532.pub3.