Chronic Obstructive Pulmonary Disease

Write about Chronic Obstructive Pulmonary Disease here.


• Smoking causes lots

• Prevalence = about 1.5 million

• Mortality = 25000/yr in England and Wales, 3 million world wide

COPD = disease state characterised by presence of airway obstruction, with little or no reversibility; due to chronic bronchitis or emphysema

• Tobacco smoking is the main cause - pack year = 20/day/year

• Nearly all patients with COPD smoked, but only 20% of smokings acquire COPD

• Two main clinical patterns:

• blue bloaters

poorly preserved ventilatory function, low PaO2 and high PaCO2

• Cyanosed but not breathless

• May develop Cor Pulmonale

• easily drift into Type II Respiratory Failure (PaO2 <8, PaCO2 >6)

• Relatively insensitive to CO2 and so have a hypoxic respiratory drive -> care with O2

• pink puffers

• well preserved ventilatory function, with near normal PaO2 and normal or low PaCO2 

• Breathless but not cyanosed

• May progress to Type I Respiratory Failure (PaO2 < 8, PaCO2 normal or low)


Tests:

• CXR => hyperinflation (>6 anterior ribs)

Lung Function Tests

• ABG

• CT

• Sputum

• Assessment:

Mild: FEV1 = 60-80% predicted

• Moderate: FEV1 = 40-59% predicted

• Severe: FEV1 = <40% predicted


• Treatment:

• STOPPING SMOKING

• Bronchodilators

• Steroids - 20-30% of patients improve with steroids

• Abx

• LTOT - long term oxygen therapy, consider if PaO2 <7.3 despite maximal treatment, 7.3-8+PulHTN+Cor pulmonale.  If maintained >8, 3 yr survival improved by 50% -> to improve prognosis rather than improve symptoms


Prognosis

COPD + chronic hypoxaemia - mortality rate of 50% @ 3 yrs