What is the diagnostic workup and treatment approach for COPD (Chronic Obstructive Pulmonary Disease) and asthma exacerbation, including criteria for inpatient admission and discharge planning?

COPD and Asthma Exacerbation: Diagnostic Workup, Treatment, and Inpatient Management

Initial Diagnostic Workup

For any patient presenting with suspected COPD or asthma exacerbation, immediately obtain arterial blood gas (ABG), chest X-ray, electrocardiogram, and pulse oximetry 1. These four tests form the foundation of your emergency assessment and should be ordered simultaneously upon arrival.

Essential Laboratory and Imaging Studies

• ABG analysis is mandatory to assess PaO2, PaCO2, and pH—this guides oxygen therapy targets and identifies respiratory failure requiring ICU admission 1
• Chest X-ray to exclude pneumonia, pneumothorax, pulmonary edema, and lung cancer—all common mimics or complications of COPD exacerbation 1
• ECG to identify cardiac arrhythmias and congestive heart failure, which are high-risk comorbidities requiring hospitalization 1
• Pulse oximetry for continuous monitoring, targeting SpO2 88-92% in COPD patients (not >92%, as excessive oxygen worsens V/Q mismatch and hypercapnia) 2

Additional Diagnostic Considerations

• Sputum culture if purulent sputum is present, though treatment should not be delayed awaiting results 1
• Spirometry is NOT required during acute exacerbation but should be documented in the patient's history to confirm COPD diagnosis 3
• Blood tests including complete blood count, electrolytes (maintain K+ >4.0 mEq/L and Mg2+ >2.0 mg/dL for respiratory muscle function), and inflammatory markers 2

Criteria for Inpatient Admission

Admit the patient if any of the following criteria are present 1:

Absolute Indications for Hospitalization

• Inadequate response to outpatient management or marked increase in dyspnea 1
• Worsening hypoxemia or hypercapnia on ABG 1
• Changes in mental status (confusion, lethargy, altered consciousness) 1
• Inability to eat or sleep due to respiratory symptoms 1
• High-risk comorbidities: pneumonia, cardiac arrhythmia, congestive heart failure, diabetes mellitus, renal or liver failure 1
• Inadequate home support or inability of patient to care for themselves 1
• Uncertain diagnosis requiring further evaluation 1

ICU Admission Criteria

Transfer to ICU immediately if 1:

• Impending or actual respiratory failure (pH <7.35 with hypercapnia warrants intermediate ICU; pH <7.25 requires full ICU) 1
• Hemodynamic instability or shock 1
• Other end-organ dysfunction (renal, hepatic, or neurological disturbance) 1

Inpatient Treatment Protocol

Oxygen Therapy

Target PaO2 ≥8 kPa (60 mmHg) or SpO2 88-92%—never exceed SpO2 of 92% in COPD patients 1, 2. Higher oxygen levels increase CO2 retention risk and worsen respiratory acidosis 1, 2.

• Monitor ABG at 30-60 minutes after any intervention to detect worsening acidosis 2
• Maintain semi-recumbent position (30-45 degrees) to improve diaphragmatic function 2

Bronchodilator Therapy

Administer short-acting β2-agonist (albuterol/salbutamol) AND ipratropium via MDI with spacer, 2 puffs every 2-4 hours 1. For severe cases, use nebulized albuterol 2.5-5 mg every 4-6 hours 2.

• MDI with spacer is as effective as nebulizer once stabilized 4
• Verify proper inhaler technique before discharge 1, 4
• Consider adding long-acting bronchodilator if not already prescribed 1

Systemic Corticosteroids

Give prednisone 30-40 mg orally daily for 10-14 days 1. If patient cannot tolerate oral medications, use equivalent IV dose (methylprednisolone 40-60 mg IV every 6-8 hours) 2.

• This is evidence-based for COPD exacerbations and should be standard therapy 1
• Do NOT continue long-term beyond 14 days 1

Antibiotic Therapy

Prescribe antibiotics if patient has ≥2 of the following: increased breathlessness, increased sputum volume, or purulent sputum 1.

First-line options based on local resistance patterns 1:

• Amoxicillin/ampicillin, cephalosporins, doxycycline, or macrolides
• If prior antibiotic failure: amoxicillin/clavulanate or respiratory fluoroquinolones 1
• Ensure 5-7 day course completion 4

Ventilatory Support

Initiate noninvasive positive pressure ventilation (NPPV) if pH <7.35 with hypercapnia 1. Use combination of CPAP (4-8 cmH2O) plus pressure support ventilation (10-15 cmH2O) 1.

For intubated patients 2:

• Tidal volume 6-8 mL/kg ideal body weight to prevent barotrauma
• Respiratory rate 16-20 breaths/min to enhance CO2 elimination
• Low PEEP (3-5 cm H2O) initially, titrate cautiously to avoid hyperinflation

Nutritional and Electrolyte Management

• Provide 25-30 kcal/kg/day to prevent malnutrition common in COPD 2
• Maintain K+ >4.0 mEq/L and Mg2+ >2.0 mg/dL for optimal respiratory muscle function 2
• Use diuretics (furosemide 20-80 mg IV) if concurrent heart failure with pulmonary congestion 2

Admission Orders Template

Upon admission, order the following 1, 2:

1. Continuous pulse oximetry targeting SpO2 88-92%
2. Supplemental oxygen via nasal cannula or Venturi mask
3. Albuterol/ipratropium MDI with spacer 2 puffs every 2-4 hours
4. Prednisone 40 mg PO daily for 10-14 days
5. Antibiotic (if indicated by sputum criteria)
6. ABG at baseline and 30-60 minutes after interventions
7. Chest X-ray, ECG, CBC, comprehensive metabolic panel
8. Semi-recumbent positioning at 30-45 degrees
9. Respiratory therapy consultation for inhaler technique education
10. Dietary consultation for nutritional support (25-30 kcal/kg/day)

Discharge Planning and Criteria

Readiness for Discharge

Discharge when ALL of the following are met 1:

• Patient stable on MDI therapy (not requiring nebulizers) for ≥24 hours 4
• SpO2 ≥90% on room air or baseline oxygen requirement 1
• Able to eat, sleep, and ambulate without severe dyspnea 1
• Demonstrates proper MDI technique 1, 4
• Has adequate home support and follow-up arranged 1

Discharge Medications

Prescribe the following at discharge 4:

1. Short-acting β2-agonist (albuterol) MDI with spacer: 2 puffs (90 μg/puff) every 2-4 hours as needed 4
2. Ipratropium bromide MDI: for patients with severe symptoms or poor response to β-agonist alone 4
3. Prednisone 30-40 mg daily: to complete 10-14 day course 4
4. Antibiotics: complete 5-7 day course if started 4
5. Inhaled corticosteroids: consider for patients with frequent exacerbations 4

Critical Discharge Instructions

• Verify MDI technique with teach-back method before discharge 4
• Transition from nebulizer to MDI at least 24 hours before discharge to ensure stability 4
• Schedule follow-up within 30 days (ideally 4-6 weeks) to reduce readmission risk 1, 4

Follow-Up Assessment (4-6 Weeks Post-Discharge)

At follow-up visit, evaluate 1:

• Patient's ability to cope with home environment
• FEV1 measurement to assess recovery
• Inhaler technique and treatment regimen understanding
• Need for long-term oxygen therapy (LTOT) in severe COPD
• Smoking cessation counseling and lifestyle modifications (weight, exercise)
• Reassess for home nebulizer only if MDI therapy inadequate

Common Pitfalls to Avoid

Never target SpO2 >92% in COPD patients—this worsens hypercapnia through V/Q mismatch and can precipitate respiratory acidosis 2. This is one of the most common and dangerous errors in COPD management.

Do not discharge on nebulizer therapy unless MDI with spacer has been tried and failed—nebulizers delay discharge and are no more effective once stabilized 4.

Do not continue oral corticosteroids beyond 14 days unless there is documented prior response or ongoing indication 1. Long-term steroids increase infection risk, including pneumonia.

Always recheck ABG 30-60 minutes after any intervention to recognize worsening acidosis early 2. Delayed recognition of respiratory failure is a major cause of preventable mortality.

Ensure follow-up is scheduled before discharge—patients without scheduled follow-up within 30 days have significantly higher readmission rates 4.