COPD exacerbation

Background

• Airflow limitation (FEV1:FVC < 0.70) that is not fully reversible
  • Encompasses chronic bronchitis (85%) and emphysema (15%)
• Acute exacerbations due to incr V/Q mismatch, not expiratory airflow limitation

Precipitants

1. Infection (75%)
   1. 50% viral, 50% bacterial
2. Cold weather
3. B-blockers
4. Narcotics
5. Sedative-hypnotic agents
6. PTX
7. PE

Diagnosis

• Increase in cough, sputum, or dyspnea
• Hypoxemia
• Tachypnea
• Tachycardia
• HTN
• Cyanosis
• AMS
• Hypercapnia

DDX

1. Asthma
   1. More likely in younger pt (<50yo)
2. PNA
   1. Frequently coexists w/ COPD exacerbation
3. CHF
   1. Can coexist w/ COPD
   2. Orthopnea, interstitial edema more c/w CHF
   3. BNP >500 very likely to be CHF
4. PE
   1. 20% of pts w/ severe COPD exacerbation of unclear trigger have a PE
5. ACS
6. PTX
   1. COPD is major risk factor for PTX

Work-up

1. VBG/ABG
   1. Perform if SpO2 <90% or concerned about symptomatic hypercapnia
2. Peak flow
   1. <100 indicates severe exacerbation
3. CXR
   1. Consider if concerned for PNA or CHF
4. Sputum culture
   1. Usually not indicated except for pt w/ recent antibiotic failure

Pseudomonas Risk Factors

1. Recent hospitalization (>2 days within previous 3 months)
2. Frequent abx tx (>4 courses w/in past year)
3. Severe underlying COPD (FEV1 < 50% predicted)
4. Previous isolation of pseudomonas

Treatment

1. O2
   1. Maintain PaO2 of 60-70 or SpO2 90-94%
   2. If unable to correct hypoxemia with a low FiO2 consider alternative diagnosis
   3. Adequate oxygenation is essential, even if it leads to hypercapnia
   4. If hypercapnia leads to AMS, dysrhythmias, or acidemia consider mechanical ventilation
2. Albuterol/ipratropium
3. Steroids ("low-dose," oral preferred)
   1. Duration = 7-10d (no tapering required)
   2. Oral: Prednisone 40-60mg daily
   3. IV: Methylprednisolone 60-125mg BID-QID
4. Antibiotics
   1. Indicated for:
      1. Increased sputum volume or change in color
      2. Fever
      3. Suspicion of infectious etiology of exacerbation
   2. Options:
      1. Outpatient Healthy
         1. Azithromycin OR doxycline OR TMP/SMX
      2. Outpatient Unhealthy
         1. Age >65, cardiac disease, >3 exacerbations/pyr
            1. 1. Levofloxacin/moxifloxacin OR amox/clavulanate
   3. Inpatient
      1. Pseudomonas risk factors:
         1. Levofloxacin PO or IV OR cefepime IV OR Ceftazadine IV OR pip-tazo IV
      2. No pseudomonas risk factors:
         1. Levo/moxifloxacin PO or IV OR ceftriaxone IV OR cefotaxime IV
      3. Consider oseltamivir during influenza season
5. Noninvasive ventilation (CPAP or BiPaP)
   1. CPAP: start at low level and titrate up to max 15
   2. BiPAP: Start IPAP 8 (max 20), EPAP 4 (max 15)
   3. Contraindications:
      1. Uncooperative or obtunded pt
      2. Inability to clear secretions
      3. Hemodynamic instability
6. Mechanical ventilation
   1. Indications
      1. Severe dyspnea w/ use of accessory muscles and paradoxical breathing
      2. RR>35 bpm
      3. PaO2 <50 or PaO2/FiO2 <200
      4. pH <7.25 and PaCO2 >60
      5. Altered mental status
      6. Cardiovascular complications (hypotension, shock, CHF)

Disposition

Consider hospitalization for:

1. Marked increase in intensity of symptoms (e.g. sudden development of resting dyspnea)
2. Background of severe COPD
3. Onset of new physical signs (e.g., cyanosis, peripheral edema)
4. Failure of exacerbation to respond to initial medical management
5. Significant comorbidities
6. Newly occurring arrhythmias
7. Diagnostic uncertainty
8. Older age
9. Insufficient home support

Source

• NEJM 4/10
• UpToDate
• Tintinalli