An In Vitro Study to Investigate the Use of a Breath-Actuated, Small-Volume, Pneumatic Nebulizer for the Delivery of Methacholine Chloride Bronchoprovocation Agent
Bibliographic record
Abstract
BACKGROUND: Current American Thoracic Society and American Association for Respiratory Care guidelines for the delivery of aerosol agents such as methacholine chloride (MC) for bronchoprovocation testing require the use of pneumatic jet nebulizers that have well-defined droplet size and mass output. A recently developed disposable, breath-actuated nebulizer (AeroEclipse) may offer bronchoprovocation testers an alternative to existing devices. METHODS: We studied the performance of 5 AeroEclipse nebulizers with regard to mass of MC delivered with various MC solution concentrations and numbers of inhalations, using a model of adult tidal breathing. Each nebulizer was operated with compressed air (8 L/min at 50 psig) and an initial fill of 2 mL. MC solutions with mass concentrations of 0.25, 0.98, 3.85, and 15.70 mg/mL were tested. The total mass of MC delivered was determined after 5, 10, and 15 complete breathing cycles, by assaying the MC collected on a filter placed at the nebulizer mouthpiece. The aerosol droplet size distribution, fine droplet fraction (FDF) (percentage of droplets < 4.8 microm diameter), and fine droplet mass (FDM) (mass of droplets < 4.8 microm diameter) were determined by laser diffractometry, using physiologically normal saline as a surrogate for MC solution. RESULTS: The mean +/- SD FDM collected in 5 breathing cycles was 654 +/- 29 microg with the 15.70 mg/mL solution, 158 +/- 9 microg with the 3.85 mg/mL solution, 37 +/- 3 microg with the 0.98 mg/mL solution, and 7 +/- 2 microg with the 0.25 mg/mL solution. FDM showed a linear correlation (r(2) = 0.9999) with MC concentration, within the range studied. FDM also showed a linear correlation (r(2) = 0.999) with the number of breathing cycles. For instance, with the 15.70 mg/mL solution, FDM was 654 +/- 29 microg with 5 breathing cycles, 1,228 +/- 92 microg with 10 breathing cycles, and 1,876 +/- 132 microg with 15 breathing cycles. CONCLUSIONS: Although the bronchoprovocation test procedure had to be slightly modified from the guidelines to accommodate the operation of the AeroEclipse's breath-actuation feature, our measurements indicate that a predictable dose of MC, within the useful range for bronchoprovocation testing, can be delivered to an adult patient breathing tidally. The green indicator on the AeroEclipse could be used to coach the patient to inhale for a specific period, thereby controlling MC delivery per breathing cycle.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".