AECOPD

Some interesting articles about morning report:

The Matrix article

The Pimping article

Points about COPD

Definition: (WHO)"Chronic obstructive pulmonary disease (COPD) is a preventable and treatable disease with some significant extrapulmonary effects that may contribute to the severity in individual patients. Its pulmonary component is characterized by airflow limitation that is not fully reversible. The airflow limitation is usually progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases."

NOTE THAT COPD IS NOT AN ISOLATED LUNG DISEASE BUT HAS SYSTEMIC EFFECTS

Diagnosis: symptoms compatible with COPD, airflow obstruction (FEV1/FVC ratio less than 0.70 with no alternative cause.

Severity based on FEV1

Mild: FEV1 over 80% of predicted, with or without symptoms

Moderate COPD -FEV1 50-80% predicted

Severe COPD- FEV1 30-50%

Etiologies of exacerbations:

Majority are infection-related (80%) - H. Flu; S. Pneumo; M. Catarrhalis; P. Aeruginosa (5-10%); Rhinoviruses (20-25%).

15-20% are from other causes (inhaled irritants, air pollution)

Treatment consists of

1) Bronchodilators

2) Systemic steroids

3) ABx

4) Ventilatory support if needed (including BiPAP)

Abx - NOT needed for all exacerbations. Some advocate using only if increased sputum purulence. Classically used in all exacerbations requiring assisted ventilation (possible mortality benefit) or when there are 2 or more of increased dyspnea, sputum production or sputum purulence. One of the earlier papers to address that is referenced here.

Steroids: Trials have demonstrated benefit of systemic steroids for vs. placebo. No mortality benefit, but shorter length of stay, PFT improvement, and symptomatic improvement.

Original trial used Solumedrol 125mg IV q8h; no advantage to this high dose over Prednisone 40-60mg PO x 5-7d. No need for taper of this duration.

A NEJM paper from 2002 reviewing AECOPD is here

Obstructive lung disease

At physical exam rounds, we discussed the diagnosis of obstructive lung disease.

There are many potential findings, outlined below, and 3 major papers on the evidence-based diagnosis of obstructive lung disease.


Possible findings:

General inspection:
Signs of respiratory distress (accessory muscle use, indrawing, paradoxical abdominal movement), pursed lip breathing, barrel chest, signs of malnutrition, look for clubbing (not expected in COPD), asterixis from CO2 retention, cyanosis, elevated JVP from cor pulmonale, many other possibilities...

Vitals:
Pulsus paradoxus

Palpation:
Subxiphoid cardiac impulse, palpable P2 from pulmonary HTN

Percussion:
Hyperresonance
Decreased diaphragmatic excursion
Decreased cardiac dullness

Auscultation:
Wheezes

Special manouevers:
Forced expiratory time (Patient takes a deep breath and exhales forcefully with open mouth, and examiner listens over lower trachea)
Laryngeal height- measure the maximum distance between the sternal notch and the thyroid cartilage. Less than 4cm is significant.

Evidence:

From JAMA Rational Clinical exam (1995):

Most sensitive tests (i.e. rule out if not present)- no single test sensitive enough
Most specific tests (i.e. rule in if present)
Wheezing (LR 36)
Barrel chest (LR 10)
Decreased cardiac dullness (LR 10)
Match test (patient unable to blow out match held 10cm in front with open mouth) (LR 7.1)
Hyperresonance
Forced exp time over 9 seconds
Other less useful tests to rule in, but positive LR's: Forced exp time 6-9s, subxiphoid impulse, pulsus paradoxus over 15, decreased breath sounds.


From JGIM- Straus et al, 2002
Took 161 pts with varying disease severity (known, suspected, or no COPD), did spirometry on all, looked at components of history and physical that predicted FEV1 5th percentile.

Key point here is combining findings is powerful in ruling in or ruling out.

Forced exp time over 9 seconds - LR 6.7
Wheezing - LR 4.0
Self-reported COPD LR 5.6

If all 3, LR 59 (rules in). If none, LR 0.3 (i.e. good for ruling out)

Other significant features: Over 40 pack-year smoker: LR 3.3


From JAMA- Straus et al (2000)- primary study, not Rational Clinical Exam

History of smoking over 40 pack-years: LR 8.3
Self-reported COPD: LR 7.3
Maximum laryngeal height less than 4cm LR: 2.8
Age over 45 LR 1.3

If all 4, LR is over 200
If none, LR- is 0.13

Links

For JAMA Rational Clinical Exam abstract click here

For Straus et al JAMA paper click here

For Straus et al JGIM paper click here