Stress test and gastric-arterial Pco2 measurement improve prediction of successful extubation
Bibliographic record
Abstract
OBJECTIVE: Correct early prediction of successful extubation decreases morbidity and mortality. The use of single time point measurements and surrogate markers of true extubation success limits weaning studies. Our aim was to determine whether a "stress test" improves prediction of extubation outcome and to determine the most predictive variables. DESIGN: Observational study. SETTING: Intensive care unit of a teaching hospital. PATIENTS: A convenience sample of 68 patients judged to be ready for extubation. INTERVENTIONS: We decreased pressure support from 5 to 0 cm H2O for 1 hr before extubation (stress test) while patients were on 5 cm H2O continuous positive airway pressure. MEASUREMENTS AND MAIN RESULTS: We measured respiratory frequency, tidal volume, ratio of respiratory frequency to tidal volume (f/VT), airway occlusion pressure after onset of inspiration (P0.1), and gastric-arterial PCO2 (deltaPg-aCO2 both on 5 cm H2O and 0 cm H2O pressure support. Then all patients were extubated. Failure of extubation was defined as reintubation within 24 hrs. Seventeen patients (25%) failed extubation. With pressure support of 5 cm H2O and continuous positive airway pressure of 5 cm H2O, most predictors were not different between patients who failed and patients who were successfully extubated. After the stress test, deltaPg-aCO2 was 2 (-5; 15) mm Hg (median; quartiles) in successfully extubated patients vs. 28 (-9; 48) in failures (p = .0003), tidal volume was 473 (387; 558) vs. 400 (323; 435) mL (p = .02), and P0.1 was 2.8 (2; 4.1) vs. 4.1 (2.7; 5.3) mm Hg (p = .03), respectively. The stress test increased specificity of deltaPg-aCO2 from 0.45 to 0.94 and positive predictive value from 0.85 to 0.97. The specificity and positive predictive values for f/VT after the stress test were 0.23 and 0.78. CONCLUSIONS: A simple stress test improves prediction of extubation outcome. deltaPg-aCO2 has superior specificity and positive predictive value compared with other variables. The use of true clinical outcome (i.e., extubation) instead of the use of surrogate markers (e.g., tachypnea) distinguishes these results from previous studies.
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 | 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".