O<sub>2</sub>concentration based definition of wait times between multiple breath nitrogen washout trials
Bibliographic record
Abstract
Introduction: The time required to perform Multiple Breath Nitrogen Washout (MBNW) testing is influenced by the time needed between trials to equilibrate intrapulmonary gas concentrations to baseline levels. Current convention is to define this time using either the length of the preceding washout, or to monitor alveolar gas concentrations have returned to baseline values. The purpose of this study was to define wait time using an end-tidal oxygen concentration ([O2]) limit based on the natural variability of end-tidal [O2]. Methods: 12 healthy adults performed MBNW testing using the Exhalyzer D® (Ecomedics AG, Switzerland). Prior to exposure to O2, an extended pre-washout phase (50 breaths (range 30-74)) was collected to define the baseline variability of the end-tidal [O2]. Subjects subsequently performed a modified MBNW testing protocol to capture the wash-in phase of [O2] following each washout. Results: The within-subject standard deviation (SD) of the [O2] in healthy adults was 0.5 %, thus the upper limit was defined as baseline [O2] + 1%. On average, healthy adults returned to baseline [O2] levels for three consecutive breaths within 3 minutes (SD 1min) or 1 times (SD 0.3) the length of the preceding washout. In 6 trials, subjects did not return to baseline [O2] despite waiting a median of 1.8 (IQR 1.5, 2.7) times the washout time. If we apply a standard of 1.5 times the previous washout, the [O2] based definition saves an average of 1.5 minutes (SD 1.1) per trial in healthy subjects. Conclusions: Defining wait time between MBNW trials based on [O2] rather than washout time may reduce total testing time. Evaluation of this approach in CF patients is ongoing.
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 machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.012 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".