Response of Ventilator-Dependent Patients to Delayed Opening of Exhalation Valve
Bibliographic record
Abstract
In conventional mechanical ventilation, the inflation cycle often extends into neural expiration (TEN), potentially exacerbating dynamic hyperinflation (DH). We wished to determine the extent to which patients defend against DH when this happens. Such defense may include prolongation of TEN (timing response) and/or expiratory muscle recruitment (neuromuscular response). Fifty patients were ventilated in the Proportional Assist mode, allowing us to infer these responses noninvasively. At random intervals, exhalation of single breaths was delayed by briefly delaying the opening of exhalation valve (occlusion) (T(occ) = 0.78 +/- 0.34 seconds). Timing response was assessed from the change in TEN. Neuromuscular response was assessed from the difference between volume exhaled after release of occlusion and volume exhaled in unoccluded breaths over a similar expiratory flow duration (DeltaV(iso-time)). There was no evidence of an acute neuromuscular response; DeltaV(iso-time) averaged 0.005 +/- 0.023 L (NS). Forty-five of 50 patients significantly lengthened TEN. However, the timing response offset only 36 +/- 20% of the delay in expiration. Because of absent neuromuscular responses and weak timing responses, DH increased in most patients in postocclusion breaths (DeltaDH = 0.10 +/- 0.08 L, p = 2E-10). We conclude that acute compensatory responses to delays in opening of exhalation value are weak in ventilator-dependent patients. As a result, such nonsynchrony tends to exacerbate DH.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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".