Studies













Reference [2]
SPIROMETRY FINDINGS IN COPD
Severity FEV₁/FVC
(postbronchodilator)
FEV₁
(% predicted
postbronchodilator)
Mild COPD ≤ 0.7 ≥ 80%
Moderate COPD ≤ 0.7 50 - 80%
Severe COPD ≤ 0.7 30 - 50%
Very Severe COPD ≤ 0.7 < 30%



Reference [4]
NORMAL ABG VALUES
Measure Normal range
pH 7.3 - 7.5
PaO₂ ≥ 80 mmHg
PaCO₂ 30 - 50 mmHg
HCO₃ 21 - 27 mEq/L
SaO₂ ≥ 95%
Reference [4]
RELATION BETWEEN PaO₂ and SaO₂
Degree of hypoxemia PaO₂ SaO₂
Normal ≥ 80 mmHg 95 - 100%
Mild 60 - 79 mmHg 90 - 94
Moderate 40 - 59 mmHg 75 - 89%
Severe < 40 mmHg < 75%









Study Criteria Intervention Primary outcome Results
Azithromycin
vs
placebo
to prevent exacerbation


NEJM
2011

PubMed abstract
Inclusion criteria:
  • Diagnosis of COPD
  • ≥ 10 pack-years smoking history
  • PFTs consistent with COPD
  • Using oxygen or had received steroids within one year
  • Been to ER or hospitalized for COPD

Exclusion criteria:
  • Asthma
  • Resting heart rate > 100 bpm
  • A prolonged QT interval or using medications that prolong the QT interval
Group 1 (558 patients) - Azithromycin (Zithromax®) 250mg once a day for 1 year

Group 2 (559 patients) - Placebo once a day for 1 year

  • About 50% of the patients in both groups were on triple therapy with a long-acting beta agonist, long-acting anticholinergic agent, and an inhaled corticosteroid
The primary outcome was the time to the first acute exacerbation of COPD, defined as “a complex of respiratory symptoms (increased or new onset) of more than one of the following: cough, sputum, wheezing, dyspnea, or chest tightness with a duration of at least 3 days requiring treatment with antibiotics or systemic steroids" Primary outcome
Group 1 - The median time to the first exacerbation was 266 days
Group 2 - The median time to the first exacerbation was 174 days (difference between groups - p-value <0.001)

Other
  • The frequency of exacerbations was 1.48 exacerbations per patient-year in the azithromycin group, as compared with 1.83 per patient-year in the placebo group (p-value=0.01)
  • Hearing loss was more common in the azithromycin group than in the placebo group (25% vs. 20%, p-value=0.04)



References: