From the Guidelines
Yes, increased Total Lung Capacity (TLC) and Raw (airway resistance) on pulmonary function tests (PFTs) can be associated with post-COVID long haul syndrome. While COVID-19 typically causes restrictive lung patterns with decreased TLC, some long COVID patients develop hyperinflation with increased TLC due to air trapping from small airway dysfunction, as suggested by the European Society of Clinical Microbiology and Infectious Diseases guidelines for long COVID management 1. Increased Raw indicates airway obstruction, which can result from persistent inflammation or remodeling of airways following COVID infection. These findings may be part of a post-viral reactive airway syndrome similar to what's seen after other respiratory infections.
Key Considerations
- The European Society of Clinical Microbiology and Infectious Diseases recommends considering routine blood tests, chest imaging, and pulmonary function tests for patients with persistent respiratory symptoms at 3 months 1.
- Physical and respiratory rehabilitation should be considered for patients with persistent symptoms of COVID-19, as suggested by the guidelines 1.
- Treatment might include inhaled bronchodilators like albuterol or formoterol, possibly combined with inhaled corticosteroids like budesonide to address inflammation.
Management
- It's essential to have these findings evaluated by a pulmonologist who can monitor progress over time, as some post-COVID lung changes may improve gradually over 6-12 months.
- Pulmonary rehabilitation can also help improve lung function, and its consideration is supported by the guidelines for long COVID management 1.
From the Research
Increased TLC and Raw on PFT
- Increased Total Lung Capacity (TLC) and airway resistance (Raw) on Pulmonary Function Tests (PFT) can be indicative of various respiratory conditions, including those related to post-COVID-19 complications 2, 3.
- Post-COVID-19 patients may experience persistent respiratory symptoms, including dyspnea, cough, and chest tightness, which can be associated with abnormal PFT results 4, 5.
- Studies have shown that some patients with post-COVID-19 syndrome may have increased TLC and Raw on PFT, suggesting possible airway obstruction or restriction 2.
- The use of bronchodilators, such as salbutamol, may improve lung function in post-COVID-19 patients, including those with increased TLC and Raw on PFT 2.
- Inhaled corticosteroids have also been investigated as a potential treatment for post-COVID-19 respiratory symptoms, including those with increased TLC and Raw on PFT, although the evidence is still limited 3.
Potential Causes and Treatments
- Increased TLC and Raw on PFT in post-COVID-19 patients may be related to various factors, including airway inflammation, bronchospasm, or pulmonary fibrosis 4, 5.
- Treatment options for post-COVID-19 patients with increased TLC and Raw on PFT may include bronchodilators, inhaled corticosteroids, and other respiratory therapies, such as oxygen therapy or pulmonary rehabilitation 2, 3.
- Further research is needed to fully understand the causes and consequences of increased TLC and Raw on PFT in post-COVID-19 patients and to develop effective treatment strategies 6.