What do an Forced Expiratory Volume in 1 second (FEV1) of 58% and Residual Volume (RV) of 228% indicate?

Interpretation of FEV1 58% and RV 228%

An FEV1 of 58% predicted combined with an RV of 228% predicted strongly indicates moderate to severe COPD with significant air trapping and hyperinflation.

Spirometric Pattern Analysis

This pulmonary function test pattern shows:

• FEV1 of 58% predicted: According to GOLD 2025 guidelines, this falls in the moderate COPD range (50-69% predicted) 1
• RV of 228% predicted: This represents severe air trapping, with residual volume more than double the normal value
• Combined interpretation: The moderately reduced FEV1 with markedly elevated RV indicates an obstructive ventilatory defect with significant hyperinflation

Physiological Significance

This pattern reflects several key pathophysiological processes:

• Airflow limitation: The reduced FEV1 indicates moderate airflow obstruction during forced expiration
• Air trapping: The markedly elevated RV (228%) demonstrates severe air trapping, where air cannot be fully expelled during expiration 2
• Hyperinflation: The elevated RV indicates lung hyperinflation, a hallmark of COPD, particularly in emphysematous phenotypes
• Small airway involvement: This pattern suggests significant small airway disease, as RV correlates better with small airway function (FEF25-75%) than with FEV1 3

Clinical Implications

1. Disease severity:

   • Moderate COPD based on FEV1 (58% predicted) 1
   • More severe disease than FEV1 alone would suggest, given the marked hyperinflation

2. Therapeutic considerations:

   • Likely to benefit from bronchodilator therapy targeting air trapping
   • Studies show that regardless of baseline FEV1, the most consistent improvement following bronchodilation is RV reduction 2

3. Functional impact:

   • Air trapping and hyperinflation contribute significantly to dyspnea and exercise limitation
   • Elevated RV/TLC ratio (not provided but likely elevated) correlates with dyspnea and reduced exercise capacity

Differential Diagnosis

While this pattern is most consistent with COPD, other conditions to consider include:

• Asthma with fixed obstruction: Though typically asthma shows greater bronchodilator reversibility
• Asthma-COPD overlap syndrome: Consider if there is significant bronchodilator response
• Bronchiectasis: May present with similar pattern but would have additional clinical features

Recommended Follow-up

1. Bronchodilator reversibility testing if not already performed

   • Significant response (≥12% and ≥200mL improvement in FEV1) would suggest asthmatic component 4

2. Complete lung volume measurements including:

   • Total Lung Capacity (TLC)
   • RV/TLC ratio (likely elevated >40%)
   • Diffusing capacity (DLCO) to assess for emphysematous changes

3. Flow-volume loop assessment to evaluate pattern of obstruction

Common Pitfalls to Avoid

• Underestimating disease severity: Don't rely solely on FEV1; the markedly elevated RV indicates more severe disease
• Missing bronchodilator response: Even with moderate obstruction, significant improvements in air trapping (RV) may occur with bronchodilator therapy 2
• Overlooking small airway disease: The elevated RV may reflect small airway involvement even when FEV1 is only moderately reduced

In summary, this pulmonary function pattern represents moderate COPD with significant air trapping and hyperinflation, warranting appropriate therapeutic interventions targeting both airflow limitation and hyperinflation.