Ventilation dynamics using a portable device coupled to the six-minute walk test in people with long-COVID syndrome: a preliminary study.

OBJECTIVE: To investigated the dynamic ventilatory responses and their influence on functional exercise capacity in patients with long-COVID-19 syndrome (LCS). RESULTS: Sixteen LCS patients were subjected to resting lung function (spirometry and respiratory oscillometry-RO) and cardiopulmonary performance to exercise (Spiropalm®-equipped six-minute walk test-6MWT and cardiopulmonary exercise test-CPX). At rest, spirometry showed a normal, restrictive and obstructive pattern in 87.5%, 6.25% and 6.25% of participants, respectively. At rest, RO showed increased resonance frequency, increased integrated low-frequency reactance and increased difference between resistance at 4-20 Hz (R4-R20) in 43.7%, 50%, and 31.2% of participants, respectively. The median of six-minute walking distance (DTC6) was 434 (386-478) m, which corresponds to a value of 83% (78-97%) of predicted. Dynamic hyperinflation (DH) and reduced breathing reserve (BR) were detected in 62.5% and 12.5% of participants, respectively. At CPX, the median peak oxygen uptake (VO2peak) was 19 (14-37) ml/kg/min. There was a significant correlation of 6MWD with both R4-R20 (rs=-0.499, P = 0.039) and VO2peak (rs=0.628, P = 0.009). Our results indicate that DH and low BR are contributors to poor exercise performance, which is associated with peripheral airway disease. These are promising results considering that they were achieved with simple, portable ventilatory and metabolic systems.

Relationship between exercise capacity and impulse oscillometry parameters after COVID-19 infections.

BACKGROUND: After COVID-19 infection, persistent exercise intolerance, changes in lung function have been shown. Our aim is to investigate the correlation between impulse oscillometry (IOS) parameters and exercise capacity by using incremental and endurance shuttle walk tests (ISWT, ESWT) and investigate the factors and parameters which might have an effect on both IOS parameters and exercise capacity tests. METHOD: The patients who had a history of COVID-19 were enrolled into cross-sectional study according to inclusion criteria. The IOS parameters, ISWT, ESWT, smoking status, time since COVID-19 diagnosis, length of hospital stay, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), body mass index (BMI), fat-free mass index (FFMI), dyspnea, hospital anxiety-depression and fatigue severity scores were recorded. RESULTS: The study comprised 72 patients, 71% of whom were male, with a mean age of 54 ± 10 years. After COVID-19 diagnosis, the median duration was 3 (min: 1, max: 5) months and 51 (71%) of the patients were hospitalized. The FEV1 and FVC values were in normal range. The area of reactance (AX), resonance frequency (Fres), reactance at 20 Hz (X20) and the difference between resonance at 20 and 5 Hz (R5-20) correlated with both ISWT and ESWT. The FEV1 correlated with all IOS parameters (p < 0.05). Reactance correlated with FFMI (p = 024, r = 0.267), different according to hospitalization (p = 0.02). CONCLUSION: In COVID-19 survivors, there could be correlations between IOS parameters and exercise capacity; and between these parameters and FEV and FVC. Furthermore, small airway disease with normal spirometric functions could be related to decreased exercise capacity in COVID-19 survivors regardless of concomitant diseases, BMI, smoking status and time since COVID-19 diagnosis.

Abnormal FeNO post COVID-19

Background: Airway inflammation post COVID-19 is a possible cause for persistent breathlessness. Aim(s): We sought to evaluate the role of fractional exhaled nitric oxide (FeNO) measurements in this cohort. Methodology: We report FeNO results in patients undergoing lung function testing as part of the PHENOTYPE study (NCT 04459351). Result(s): 83 patients had FeNO performed between January and Nov 2021. Of the patients admitted to hospital (n=78), the median time to testing from discharge was 96 days (IQR 90-115). Median FeNO results for the whole cohort was 20 ppb (16-29). 24/83 (29%) had a FeNO in the intermediate range [median 33 (IQR 28-45)], and 5/83 (6%), FeNO >50 ppb. Chi squared testing revealed no relationship between patient-reported breathlessness (p=0.12) or cough (p=0.45) and FeNO >=25ppb. 52 patients underwent repeat lung function and FeNO testing at a median of 363 (355-370) days post discharge. 26/52 (50%) of individuals had a FeNO>=25 ppb, with a median 35 (28-42): 10/52 (19%) deteriorated from normal to intermediate range and 2/52 from intermediate to high range as compared to initial values. 7/52 (13%) of FeNO results that were abnormal at the first visit, normalized with no additional treatment. Again, no association was found between breathlessness (p=0.48) or cough (p=0.73) at the second visit and a FeNO result >=25ppb. None of the patients with a FeNO >= 25 had a prior diagnosis of asthma. Conclusion(s): The clinical relevance of an intermediate or high FeNO in this cohort is unclear. However, this preliminary work highlights that in a significant proportion of patients, the FeNO is not normal even at 1 year post discharge. The trajectory of these changes and in particular, development of small airways disease are important to study.

Small airways disease post COVID-19: 1 year follow up

Background: Small airway disease (SAD) can occur following viral infection, but the prevalence of this in individuals recovering post SARS-COV2 infection is not known. Aim(s): We sought to assess the prevalence of SAD in patients 1 year post hospital discharge for COVID-19. Method(s): A subset of patients recruited to the PHENOTYPE study (NCT 04459351) underwent forced oscillometry assessment (THORASYS). We assessed the fall in resistance from 5 to 20 Hz (R5-R20) as a marker of peripheral airway dysfunction. A value of >0.07kPa/L/s was used as a cut off definition for small airways dysfunction. All patients had lung function testing and a clinical assessment of symptoms within a median of 7.5 (IQR 4-15) days and median of 7 (IQR 4-11) days, respectively, of small airways testing. Result(s): 40 patients were enrolled between November 2021 and January 2022, at a median of 371 days (IQR 359- 380) post hospital discharge. 31/40 (78%) were male with a median age of 63 (IQR 51-72). The median length of hospital stay was 6.5 days (IQR 4-12). 11/40 patients had required non-invasive ventilation and 29/40 oxygen therapy alone. 11/40 (28%) of patients had evidence of SAD. Self-reported breathlessness (p=0.75) and cough (p=0.50) at 1 year were not increased in SAD. Similarly, there was no association between SAD and ventilatory status (p=0.98), FENO>=25 (p=0.63) or FENO> 50 (p=0.86) at 3 months or FENO >=25 (p=0.87) or FENO>50 (p=0.29) at 1 year. Conclusion(s): Small airways disease is present in patients recovering post COVID-19 but the risk factors for developing this is unclear. Longitudinal studies are required to assess the trajectory and long term impact of small airways pathology.

Non-Detection of Post Covid Pulmonary Fibrosis (PCPF)through HRCT and PFT but possible throughTransbronchial Lung Biopsy

Background: 49 patients underwent Lung Biopsy due to different indications and Post-COVID Pulmonary Fibrosis(PCPF) was suspected in 25 patients. Objective(s): To document the evidence of PCPF in patients with history of suspected COVID 19 infection (in past oneyear) through Transbronchial Lung Biopsy(TBLB)with flexible bronchoscopy. PFT and HRCT gave variedpresentation. Method(s): we have evaluated patients who underwent Lung Biopsy on flexible Bronchoscopy between 08/07/2021 till31/01/2022 at Metro Hospitals and Heath Institute, Meerut, UP, India. The history of exposure to COVID 19 infectionwas taken. Most of these patients underwent Echocardiography (ECHO) for Left Ventricular Ejection Fraction (LVEF)and Pulmonary Artery Pressure (PAH), Pulmonary Function Test (PFT) and High Resolution CT Scan Chest (HRCTChest). Result(s): 49 patients underwent Lung Biopsy. 25 patients gave the history of exposure to COVID 19 infection with complaint of breathlessness and chest discomfort in the last 1 year. HRCT chest was suggestive of Atelectasis in 3 patients, Interstitial Lung Disease (ILD) in 6, Fibrosis in 8, Pulmonary Nodules in 4 and HRCT was not done in 4 patients. PFT showed Mixed Ventilator Defect in 8, Obstructive in 3, Restrictive in 7, small airway disease in 1 and 6 patients couldn't perform PFT. PAH was normal for 6,mild for 16, moderate for 2 and 1 severe. 4 patients had Coronary Artery Disease. 2 patients had major complications like pneumothorax who underwent TBLB. Conclusion(s): PCPF was detected with the help of TBLB in the patients with history of exposure to COVID 19 infection. However, TBLB may cause major complication like pneumothorax seen in 8% cases.

Identification and Follow-up of COVID-19 Related Matching Ventilation and Perfusion Defects on Functional Imaging Using VQ SPECT/CT.

Purpose: Available clinical data have revealed that coronavirus disease 2019 (COVID-19) is associated with a risk of pulmonary microthrombosis and small airway disease. These patients present with varying degrees of perfusion abnormalities. The purpose of this study was to evaluate the use of a ventilation/perfusion single-photon emission computed tomography/computed tomography (VQ SPECT/CT) in the detection and follow-up of persistent lung perfusion abnormalities that were suspected to be due to pulmonary microthrombosis, small airway disease, or both. Methods: A retrospective study was conducted at the department of nuclear medicine of Universitas Academic Hospital in Bloemfontein, South Africa. We reviewed the studies of 78 non-hospitalized patients with COVID-19 infection referred to our department from July 2020 to June 2021 for a perfusion only SPECT/CT study or a VQ SPECT/CT study. Pulmonary embolism was suspected in all 78 cases. Results: Seventy-eight patients were studied. The median (interquartile range) age was 45 (41-58) years, and the majority (n = 69; 88.5%) were females. Twenty-two (28.2%) of these patients had matching VQ defects with mosaic attenuation on CT. All nine of the patients who had follow-up studies had these abnormalities persistently, even after 1 year. Conclusion: We confirm that the VQ scan is a safe and effective tool to identify and follow-up recovered COVID-19 patients with persistent ventilation and perfusion abnormalities suspicious of small airway disease and pulmonary microthrombosis.

Can home rehabilitation impact impulse oscillometry and lung ultrasound findings in patients with scleroderma-associated interstitial lung disease? A pilot study.

OBJECTIVE: Exercise has been demonstrated to be beneficial for improving physical capacity and quality of life in people with scleroderma, although knowledge of its impact on the respiratory system is limited. This study evaluated the impact of therapist-oriented home rehabilitation (TOHR) on impulse oscillometry (IOS) and lung ultrasound (LUS) findings in patients with scleroderma-associated interstitial lung disease (ILD). RESULTS: Twelve women with scleroderma underwent spirometry, IOS, and LUS before and after performing TOHR. Regarding spirometry, a normal pattern and restrictive damage were observed in five (41.7%) and seven (58.3%) participants pre-TOHR and post-TOHR, respectively. For IOS, an abnormal result was detected in nine (75%) pre-TOHR participants and six (50%) post-TOHR participants. Heterogeneity of resistance between 4-20 Hz (R4-R20) > 20% of the predicted value was observed in eight (66.7%) pre-TOHR participants and three (25%) post-TOHR participants (P = 0.031). An abnormal LUS result was observed in nine (75%) participants both pre-TOHR and post-TOHR. The main change observed was B-lines > 2, which was noted in nine (75%) participants both pre-TOHR and post-TOHR. Our findings suggest that TOHR for women with scleroderma-associated ILD improves the resistance and reactance measured by IOS, including small airway disease. Trial Registration ClinicalTrials.gov ID: NCT05041868 Registered on: 13th September 2021.