Monitoring of Heated Wire Humidifier Hygrometric Performances With Heater Plate Temperature
Bibliographic record
Abstract
BACKGROUND: Under-humidification and associated complications may occur with heated humidifiers. Hygrometric performances of heated wire humidifiers are reduced by high ambient and high outlet ventilator temperatures. Currently, there is no reliable monitoring tool to evaluate humidification performances of heated wire humidifiers in the daily practice. We sought to demonstrate the relation between humidity delivered by heated wire humidifiers and different parameters that could be used to monitor humidity of gas delivered to subjects. METHODS: On a bench test, we measured heater plate temperature, inlet chamber temperature, and delivered humidity with MR850 system. Temperature displayed on the humidifier was also recorded. The measurements were performed at different ambient temperatures and five minute ventilation levels (5, 7.5, 10, 12.5, 15 L/min). Inlet chamber temperatures varied from 20–40°C. In each condition, hygrometric measurements with the psychrometric method were performed at steady state. RESULTS: We performed 279 measurements at steady state including all conditions. We found a good correlation between heater plate temperature and absolute humidity delivered (R 2 = 0.82). This relationship was hardly affected by ambient temperature, but minute ventilation had more effect. For different minute ventilations, the correlation between heater plate temperature and absolute humidity delivered was very good with coefficient of determination R 2 from 0.87–0.98. Heater plate temperature > 62°C was a good predictor of absolute humidity delivered > 30 mg H 2 O/L (area under the curve = 0.96, sensibility 79%, specificity 94%). No correlation existed between humidity delivered and the outlet chamber temperature (displayed on the humidifier). CONCLUSIONS: In this bench study, we have shown a good correlation between heater plate temperature and humidity delivered with a heated wire humidifier. This means that a “hidden” hygrometer is built into the heated wire humidifier. Heater plate temperature should be used as a surrogate of humidity to improve the humidification monitoring.
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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 | 0.001 | 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) | 0.002 | 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".