Are the Reference Values for the Provocative Concentration of Methacholine Appropriate for Children?
Bibliographic record
Abstract
Background: Preliminary data in a randomly selected pediatric cohort study in 8-year-olds suggested a rate of positivity to a methacholine challenge test that was unexpectedly high, roughly 30%. The current recommendation for a negative methacholine test is a 20% decrease in the forced expiratory volume in one second at a dose greater than 400 μg. This was derived from studies in adults using the obsolete English Wright nebulizer. One explanation for the high incidence of positivity in the study in 8-year-olds could be that children deposit more methacholine on a μg/kg basis than adults, due to differences in their breathing patterns. The purpose of this study was to determine if pediatric breathing patterns could result in a higher dose of methacholine depositing in the lungs of children based on μg/kg body weight compared with adults. Methods: An AeroEclipse Breath Actuated nebulizer delivered methacholine aerosol, generated from a 16 mg/mL solution, for one minute, using age-appropriate breathing patterns for a 70 kg adult and a 30 and 50 kg child produced by a breathing simulator. Predicted lung deposition was calculated from the collected dose of methacholine on a filter placed at the nebulizer outport, multiplied by the fraction of the aerosol mass contained in particles ≤5 μm. The dose of methacholine on the inspiratory filter was assayed by high performance liquid chromatography (HPLC). Particle size was measured using laser diffraction technology. Results: The mean (95% confidence intervals) predicted pulmonary dose of methacholine was 46.1 (45.4, 46.8), 48.6 (45.3, 51.9), and 36.1 (34.2, 37.9) μg/kg body weight for the 30 kg child, 50 kg child, and 70 kg adult, respectively. Conclusions: On a μg/kg body weight, the predicted pulmonary dose of methacholine was greater with the pediatric breathing patterns than with the adult pattern.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| 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".