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
• Although smoking is a major risk factor for developing COPD, only 15% of smokers actually develop COPD

Precipitants

• Infection (75%)
  • 50% viral, 50% bacterial
• Cold weather
• B-blockers
• Narcotics
• Sedative-hypnotic agents
• Pneumothorax
• PE

Pseudomonas Risk Factors

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

Clinical Features

• Increase in cough, sputum, or dyspnea
• Hypoxemia
• Tachypnea
• Tachycardia
• HTN
• Cyanosis
• AMS
• Hypercapnia
• Accessory respiratory muscle use
• Pursed-lip exhalation

Differential Diagnosis

Acute dyspnea

Emergent

• Pulmonary
  • Airway obstruction
  • Anaphylaxis
  • Angioedema
  • Aspiration
  • Asthma
  • Cor pulmonale
  • Inhalation exposure
  • Noncardiogenic pulmonary edema
  • Pneumonia
  • Pneumocystis Pneumonia (PCP)
  • Pulmonary embolism
  • Pulmonary hypertension
  • Tension pneumothorax
  • Idiopathic pulmonary fibrosis acute exacerbation
  • Cystic fibrosis exacerbation
• Cardiac
  • Cardiac tamponade
  • Cardiogenic pulmonary edema (CHF)
  • Myocardial Infarction
  • Pericarditis
  • Myocarditis
• Other Associated with Normal/↑ Respiratory Effort
  • Abdominal distension
  • Anemia
  • CO Poisoning
  • Salicylate toxicity
  • Diabetic ketoacidosis (DKA)
  • Diaphragm injury
  • Electrolyte abnormalities
  • Epiglottitis
  • Flail chest
  • Hypotension
  • Metabolic acidosis
  • Pneumonia
  • Pneumothorax/hemothorax
  • Renal Failure
  • Sepsis
  • Toxic ingestion
• Other Associated with ↓ Respiratory Effort
  • Guillain-Barre syndrome
  • Multiple sclerosis
  • Myasthenia Gravis
  • Lambert-Eaton Syndrome
  • Organophosphate toxicity
  • Stroke (Main)
  • Tick paralysis

Non-Emergent

• ALS
• Ascites
• Uncorrected ASD
• Congenital heart disease
• COPD exacerbation
• Fever
• Hyperventilation
• Interstitial lung disease
• Neoplasm
• Obesity
• Panic attack
• Pleural effusion
• Polymyositis
• Porphyria
• Pregnancy
• Rib fracture
• Spontaneous pneumothorax
• Thyroid Disease
• URI

Diagnosis

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

Treatment

Oxygen

• Maintain PaO₂ of 60-70 or SpO₂ 90-94%
• If unable to correct hypoxemia with a low FiO2 consider alternative diagnosis
• Adequate oxygenation is essential, even if it leads to hypercapnia
• If hypercapnia leads to AMS, dysrhythmias, or acidemia consider Intubation

Albuterol/ipratropium

• Improves airflow obstruction and treatment should involve rapid administration upon recognition of COPD exacerbation.

Steroids

Similar efficacy between oral and intravenous. Treatment options include:

• Methylprednisolone 1-2 mg/kg IV daily (usual adult dose 125mg)
• Prednisone 40 mg PO daily

For outpatients a 5 day dose appears equally effective as longer doses and a taper is not required.

Antibiotics

Indicated for patients with purulent sputum, increased sputum production, or requiring Non Invasive Positive Pressure Ventilation

Outpatient Healthy

• Antibiotics should be a 3-5 day course and options include:
  • Azithromycin 500mg PO BID
  • Doxycycline 500 mg PO BID
  • Levofloxacin 500 mg PO BID

Outpatient Unhealthy

• Age >65, cardiac disease, >3 exacerbations/per year
• Levofloxacin/Moxifloxacin OR Amoxicillin/Clavulanate

Inpatient

• If Pseudomonas risk factors the use:
  • Levofloxacin PO or IV OR Cefepime IV OR Ceftazidime IV OR Piperacillin/Tazobactam IV
• No pseudomonas risk factors:
  • Levofloxacin or Moxifloxacin PO or IV OR Ceftriaxone IV OR Cefotaxime IV
  • Consider oseltamivir during influenza season

Evidence

Antibiotics for COPD exacerbations have an NNT of:

• 3:1 to prevent conservative treatment failure
• 8:1 to prevent short-term mortality
• 20:1 to cause diarrhea

Noninvasive ventilation (CPAP or BiPaP)

• CPAP: start at low level and titrate up to max 15
• BiPAP: Start IPAP 8 (max 20), EPAP 4 (max 15)

Contraindications:

• Uncooperative or obtunded pt
• Inability to clear secretions
• Hemodynamic instability

Mechanical ventilation

Indications:

• Severe dyspnea w/ use of accessory muscles and paradoxical breathing
• RR>35 bpm with anticipated clinical course for respiratory failure
• PaO₂ <50 or PaO2/FiO2 <200
• pH <7.25 and PaCO2 >60
• Altered mental status
• Cardiovascular complications (hypotension, shock, CHF)

Disposition

Consider hospitalization for:

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

See Also

EBQ:NIPPV in COPD