Intra-breath Oscillometry is Associated With Patient-reported Symptoms and 6-minute Walk Distance at 6 Months After Mild COVID-19 Infection
Bibliographic record
Abstract
Abstract Background: The mechanisms responsible for the persistent respiratory symptoms with mild acute COVID-19, defined by management as outpatients, have not been fully characterized as most patients have normal spirometry. Oscillometry is a different pulmonary function test that measures respiratory impedance to superimposed small pressure signals during normal breathing. It is highly sensitive to changes in lung mechanics. The current standard oscillometry output provides measurement of the mean impedance of a tidal breath. Intra-breath oscillometry is a novel technique that tracks respiratory impedance during tidal breathing to provide more detailed information about changes in lung mechanics. No studies have assessed respiratory function after acute COVID-19 infection using intra-breath oscillometry. Methods: Mild acute COVID-19 patients were enrolled in the CANCOV study at the University Health Network, and evaluated with oscillometry, spirometry, patient-reported symptom checklist, 6-minute walk distance (6MWD) test and Borg dyspnea scale between August 2020 and March 2022. Date of infection was defined by symptom onset and/or positive rapid antigen test. The intra-breath oscillometry metrics of interest were resistance at end-expiration (ReE) and end-inspiration (ReI) and reactance at end-expiration (XeE) and end-inspiration (XeI). Regression analyses were used to identify association between intra-breath oscillometry, symptoms, 6MWD and Borg dyspnea score with adjustment for age, sex and height. Results: The cohort consisted of 177 outpatients with 57.3% females and median age of 45.2 years. Spirometry was normal at 6 months post-infection. Median (IQR) z-scores of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)/FVC were 0.09 (-0.57, 0.66) and -0.22 (-0.76, 0.14); the FEV1/FVC ratio was 0.80 (0.77, 0.84), respectively. Most patients (51.7%) reported persistent symptoms including chest heaviness/tightness/pain, shortness of breath, breathing harder/faster at rest, breathing faster than normal, and fatigue. Moreover, 21.1% had functional impairment as reflected by 6MWD < lower limit of normal. Logistic regression identified ReE, ReI, XeE and XeI to be highly associated with patient-reported symptoms (P < 0.05). Linear regression revealed these metrics to be significantly associated with 6MWD and Borg dyspnea scores (P < 0.05). In contrast, spirometry did not show significant associations with patient-reported symptoms, 6MWD or Borg dyspnea score. Conclusions: At 6-months after mild acute COVID-19 infection, intra-breath oscillometry identified abnormal lung mechanics that were indiscernible by standard oscillometry and spirometry. Furthermore, the intra-breath measures were significantly associated with subjective respiratory symptoms and objective metrics that include the Borg dyspnea score and functional outcome as captured by the 6MWD.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".