CONTROLLER FOR THE MANAGEMENT OF TIDAL LIQUID VENTILATORS WITH AN INDEPENDENT PUMP SYSTEM
Bibliographic record
Abstract
In order to insert and withdraw the tidal volume of perfluorochemical liquid (PFC), the total liquid ventilation (TLV) can be efficiently performed with a pump system. The main originality of the developed prototype is that the expiratory pump is independent of the inspiratory one. Consequently, they are controlled independently. The main advantages are to allow the adjustment of the functional residual capacity (FRC) during ventilations and the optimization of the ventilation cycle. However, two main points must be considered in volume-controlled TLV: avoiding airway closure (chocked flow) during expiration and controlling the FRC volume in the lungs. For this purpose, a controller is implemented to manage the pumping system. The main function of the controller is to control with high precision the volume of liquid to insert and withdraw in the lungs. Due to uncertainties, the pump system generates small volume errors at each inspiratory and expiratory cycle. Over time, the addition of small volume errors may cause an FRC drift. To avoid this problem, the controller monitors the movement of the pumps in order to compute small corrections of the desired inspiratory and expiratory volumes. Consequently, cycle after cycle, the controller learns the command which ensures a constant FRC. In order to withdraw the tidal volume, the controller generates an exponential expiratory profile defined by a time constant. The implementation of this profile is motivated by the need to prevent the risk of airway closure. Moreover, the exponential expiratory profile reproduces the effect of gravity by which the tidal volume of PFC is withdrawn from the lungs. However, even if an exponential is used, airway closures can still appear (if the FRC is too low or the flow velocity is too high). The risk of airway closure during expiration is detected when a negative pressure limit is reached. In this case, the controller stops the expiratory pump, but adjusts the next inspiratory volume in order to ensure a constant FRC in the lungs. Experimental results in vivo and in vitro with newborn lambs confirmed the benefit of using the controller with the exponential expiratory profile. The team is supported in part by the Foundation for Research into Children's Diseases and by the Fonds Québécois pour la Recherche sur la Nature et les Technologies.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.004 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.025 | 0.010 |
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".