Using the numbers from my recent PFT test, I asked a question of Google's Artificial Intelligence platform, Gemini. I got the below analysis. What do you think?
Question: What does RV 181% in PFT test mean? FEV1/FEC is 61%. DLCO is 65%. An expiratory CT scan showed no air trapping. Oxygen saturation is very good with a range of 95 to 98 in pulmonary rehab exercises. I do feel winded when climbing stairs or walking up a path that has an incline. Would a bronchodilator help reduce the air trapping (high RV)?
Gemini Response:
Based on the results you provided, here is an interpretation of your pulmonary function tests (PFTs):
Understanding Your PFT Results
- RV (Residual Volume) at 181% Your Residual Volume (the amount of air remaining in your lungs after a maximum, forced exhalation) is 181% of the predicted value. A normal RV is typically 75% to 120% of predicted. An RV over 120-140% indicates significant "air trapping," where you cannot fully empty your lungs, leaving too much stale air behind after exhaling. A value of 181% indicates hyperinflation (air trapping). Essentially, your lungs are "overfull," and you aren't able to empty them effectively.
- FEV1/FVC at 61% The FEV1/FVC ratio is the primary tool used to diagnose obstructive lung disease (like COPD or asthma). A normal ratio is typically above 70%. Your result of 61% confirms that there is an obstruction - your airways are narrowed, making it harder for air to flow out quickly. A ratio below 70-75% is considered a hallmark of obstructive lung disease (e.g., COPD or asthma), indicating that it takes you longer to exhale. According to some metrics, a ratio of 60-69% may be categorized as a mild to moderate obstruction. While 61% is low, a doctor must interpret this alongside your total (forced vital capacity) and (forced expiratory volume in 1 second) predicted values to determine if the issue is solely obstructive or if there is a combined restriction (e.g., lungs not filling properly).
- DLCO at 65% This measures how well oxygen travels from your lungs into your bloodstream. A score of 65% is considered a mild-to-moderate reduction. This suggests that the surface area available for gas exchange (diffusion capacity) has been affected, which is common when there is damage to the air sacs (alveoli).
Interpretation of Your Results
Your results show obstructive lung disease with significant air trapping (high RV) and mild impairment in gas exchange (lower DLCO).
- Why No Air Trapping on CT? Expiratory CT scans look for regional air trapping, while the PFT (body plethysmography) measures total lung volume, which is a more sensitive test for overall air trapping. It is actually quite common for a Pulmonary Function Test (PFT) to be more sensitive than a CT scan. A CT is a snapshot in time, while a PFT measures the actual physics of your airflow. Your RV of 181% is a "gold standard" measurement for air trapping, regardless of what the visual scan showed.
- Why Good Oxygen? You can have normal oxygen saturation (SpO2) at rest or during moderate exercise, even if your lungs are inefficient at emptying (high RV), as long as your lungs can still oxygenate the blood effectively (good gas exchange).
- Why Winded? The feeling of being winded (dyspnea) on stairs/inclines is common with air trapping because your lungs remain "overinflated," making it harder to take a new, deep breath. Feeling winded on stairs despite having excellent oxygen levels (95–98%) is a classic symptom of hyperinflation. Because your lungs are already "inflated" with trapped air (that 181% RV), there isn't much room to take in a deep, fresh breath when you exert yourself. It’s like trying to inflate a balloon that is already half-full; it takes much more muscular effort, which your brain perceives as breathlessness.
Would a Bronchodilator Help?
Yes, a bronchodilator is often very effective at reducing a high RV (air trapping). Bronchodilators work by relaxing the muscles around your airways. By "opening the pipes," they:
- Reduce Airflow Resistance: Making it easier to push air out.
- Decrease RV: By helping you exhale more completely, the Residual Volume (trapped air) drops.
- Improve Exercise Tolerance: With less trapped air, your diaphragm can work more efficiently, which usually makes climbing stairs feel significantly less taxing.
Note: Even if your oxygen saturation is perfect, you can still feel very short of breath due to the mechanical "work" of breathing against trapped air.
Conclusion
The combination of a high RV, low FEV1/FVC ratio, and symptoms of breathlessness on exertion is highly suggestive of an obstructive airway disorder (like asthma or COPD). A bronchodilator, such as a long-acting beta-agonist (LABA) or muscarinic antagonist (LAMA), could help reduce the air trapping, and should be discussed with your pulmonologist or doctor.
Disclaimer: These results should be interpreted by a healthcare professional in the context of your personal health history.