ABSTRACT
Introduction : Functional follow-up of patients after Covid-19 pneumonia is essential, not only to adapt patient care but also to better understand the medium and long-term consequences of the virus on respiratory function. Among the respiratory function tests, DLCO allows to evaluate the sequelae on the quality of gas exchanges. Methods : The DLCO was measured as part of a respiratory function assessment, 3 months after recovery from Covid-19 pneumonia in a group of 469 patients. Result(s): Study population was composed of 262 males and 207 females. Mean age and body mass index (BMI) were respectively 59.45+/-12.85 years-old and 31.24+/-5.83 kg/m2. Smoking was reported in 32.9% of cases. Hospitalization was needed on 92.3%, oxygen supply in 91.8% and respiratory aid in 11.1% of cases. Mean DLCO was 74.24%+/-17.7 and was abnormal in 43% of cases whereas restriction and obstruction were found respectively in 14.8% and 4.9% of spirometry. DLCO was correlated with age (r=0.236;p<10-3), BMI (r=-0.097;p=0.036), dyspnea severity according to the mMRC score (r=-0.318;p<10-3), duration of hospitalization (r=-0.13;p=0.008), respiratory aid (r=-0.159;p=0.01), duration of oxygen need (-0.364;p<10-3), extension of pneumonia on the CT scan (r=-0.245;p<10-3), FVC (r=0.521;p<10-3), FEV1 (r=0.479;p<10-3) and TLC (r=0.290;p<10-3). Conclusions : DLCO seems to be one of the first functional parameters to be altered after Covid-19 pneumonia, which justifies its regular measurement in patient follow-up.
ABSTRACT
Introduction: After Covid-19 pneumonia, regular respiratory function assessment is necessary for the subsequent management of patients, including resting respiratory function tests and assessment of submaximal exercise tolerance by six-minute walk (6MW) test. Method(s): Six-minute walk test was undergone for 326 patients about 3 months after Covid-19 pneumonia. Physiological cost of walking (PCW) defined as the difference between maximum heart rate reached at the 6MWT and resting heart rate divided by walking speed was calculated. Result(s): Median age and BMI were respectively 61 [18-95] years-old and 30,4 [18,5-65,2] kg/m2 with a sex-ratio at 1.26. Smoking was reported in 52.8% of cases (12,45 PY). Median 6MW distance was 528 meters [48-832], corresponding of 80% [7-113] of theoric. Median PCW was 0,379 beats/meter [-1.38-5.38]. Low 6MW distance and low saturation during the test were found respectively in 33.1% and 15.2% of cases and were both correlated with DLCO (r=-0.258;p<10-3 and r=-0.423;p<10-3). Chronotropic insufficiency and chronotropic intolerance were found in 13.8% and 7% of cases. PCW was correlated with BMI (r=0.463;p<10-3), FEV1 (r=-0.175;p=0.001), FVC (r=-0.167;p=0.002) and DLCO (r=-0.161;p=0.004). Conclusion(s): Six-minute walk test is an inexpensive, easy and reliable tool that tells us about the global response to submaximal exercise, especially after Covid-19 pneumonia. It is an interesting alternative for patients follow-up, especially when rehabilitation is considered.