Failure of Noninvasive Ventilation for De Novo Acute Hypoxemic Respiratory Failure
Bibliographic record
Abstract
OBJECTIVES: A low or moderate expired tidal volume can be difficult to achieve during noninvasive ventilation for de novo acute hypoxemic respiratory failure (i.e., not due to exacerbation of chronic lung disease or cardiac failure). We assessed expired tidal volume and its association with noninvasive ventilation outcome. DESIGN: Prospective observational study. SETTING: Twenty-four bed university medical ICU. PATIENTS: Consecutive patients receiving noninvasive ventilation for acute hypoxemic respiratory failure between August 2010 and February 2013. INTERVENTIONS: Noninvasive ventilation was uniformly delivered using a simple algorithm targeting the expired tidal volume between 6 and 8 mL/kg of predicted body weight. MEASUREMENTS: Expired tidal volume was averaged and respiratory and hemodynamic variables were systematically recorded at each noninvasive ventilation session. MAIN RESULTS: Sixty-two patients were enrolled, including 47 meeting criteria for acute respiratory distress syndrome, and 32 failed noninvasive ventilation (51%). Pneumonia (n = 51, 82%) was the main etiology of acute hypoxemic respiratory failure. The median (interquartile range) expired tidal volume averaged over all noninvasive ventilation sessions (mean expired tidal volume) was 9.8 mL/kg predicted body weight (8.1-11.1 mL/kg predicted body weight). The mean expired tidal volume was significantly higher in patients who failed noninvasive ventilation as compared with those who succeeded (10.6 mL/kg predicted body weight [9.6-12.0] vs 8.5 mL/kg predicted body weight [7.6-10.2]; p = 0.001), and expired tidal volume was independently associated with noninvasive ventilation failure in multivariate analysis. This effect was mainly driven by patients with PaO2/FIO2 up to 200 mm Hg. In these patients, the expired tidal volume above 9.5 mL/kg predicted body weight predicted noninvasive ventilation failure with a sensitivity of 82% and a specificity of 87%. CONCLUSIONS: A low expired tidal volume is almost impossible to achieve in the majority of patients receiving noninvasive ventilation for de novo acute hypoxemic respiratory failure, and a high expired tidal volume is independently associated with noninvasive ventilation failure. In patients with moderate-to-severe hypoxemia, the expired tidal volume above 9.5 mL/kg predicted body weight accurately predicts noninvasive ventilation failure.
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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 | 0.003 |
| 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) | 0.001 | 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".