Post COVID Lung function after mild to moderate disease: Good prognosis, but high prevalence of hyperventilation (HV)

ABSTRACT

Background: There is evidence of persistent symptoms after COVID-19 disease in more than 50 %. of patients (pts.). We hereby report our experience with lung function tests in Post-COVID pts. in an outpatient clinic. Method(s) Since spring 2020, we offered ambulatory control of lung function and imaging after COVID-19 disease. Lung function tests (LFT) including blood gas analysis were performed. Result(s) 66 consecutive pts. (39M, 27F, age 50+/-15.1 Y, BMI 29+/-6 kg/m2) without pulmonary pre-existing condition presented with persistent symptoms 168+/-122 days after COVID. 41 pts. were treated ambulatory and 25 pts. were hospitalized (none with prolonged ventilation). LFT's were normal (TLC 99+/-18 %, VC 91+/-20 %, FEV1/VC 80+/-10 %, pO2 86+/-10 mmHg, pCO2 37+/-4 mmHg), except in 6 pts., where LFT was slightly impaired 2 showed moderate obstruction and 4 a restrictive pattern. Interestingly 22 pts. (34.9%) presented with a low pCO2, indicating different degrees of HV, inclining in F (M 7/39 vs. F 15/27, p=0.004). Also, 12 pts. with known pulmonary precondition diagnoses (6 sarcoidosis, 2 chronic hypersensitivity pneumonitis (HP), 1 non-specific interstitial pneumonia, 1 CTD-ILD, 1 asthma, 1 organizing pneumonia (OP) by primary biliary cirrhosis) presented after COVID-19 disease. In 8 of these pts. the LFT was comparable as before COVID-19 disease. One patient with HP showed prolonged recovery, one asthmatic needed intensified treatment, and one presented with a new episode of OP. Discussion(s) Our pts., who recovered from mild to moderate COVID-19 disease, presented with good prognosis with regard to LFT. HV could be one pathophysiologic mechanism for Post-COVID symptoms, particularly in F.