The Effect of Humidity on the Size of Particles Delivered from Metered-Dose Inhalers
Bibliographic record
Abstract
The presence of humidity in air supplied to intubated patients has long been identified as a limiting factor in the delivery of therapeutic aerosols during mechanical ventilation. In this work, the well-known reduction in drug delivery to the lung observed when metered-dose inhalers (MDIs) are actuated into warm, humid airflow was investigated through examination of the evolution of particle size distributions delivered from two commercial hydrofluoroalkane (HFA) MDIs actuated through a standard mechanical ventilation holding chamber. Aerosol deposition in the holding chamber and mass median aerodynamic diameter (MMAD) increased significantly with humidity for both MDIs, regardless of the presence of cosolvent and surfactant in one MDI formulation but not the other. However, in humid air MMAD decreased with distance downstream from the holding chamber, again for both MDIs studied. A modification to the popular assumption of MDI particle growth by condensation is proposed, in which condensed water evaporates back into the supplied airflow subsequent to an initial transient, nucleated condensation. It is anticipated that the present improved understanding of MDI aerosol behavior in humid air may lead to the development of enhanced techniques of drug delivery to mechanically ventilated patients.
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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 | 0.000 | 0.001 |
| 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 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".