High-flow Nasal Oxygen Versus Standard Flow Facemask Preoxygenation in Pregnant Patients: A Randomized Physiological Study
Bibliographic record
Abstract
(Anaesthesia. 2019;75:450–456) While preoxygenation is an important component of safe general anesthesia, it is often suboptimal for obstetric patients. This is due to several factors including air entrainment even with a tight-fitting mask, the need for rapid delivery of the fetus in many situations, and human factor issues. For obstetric patients, an end-tidal oxygen concentration (EtO2) ≥90% is recommended before initiating rapid sequence induction and tracheal intubation. The standard practice for preoxygenation in this population is usually either 3 minutes of tidal volume breathing or 8 vital capacity breaths with facemask administration of 100% oxygen at 15 L/min. Growing in popularity for nonobstetric patients, including children, is high-flow nasal oxygen (HFNO) to increase the time to desaturation during induction of general anesthesia; however, literature on HFNO for obstetric patients is sparse. This study aimed to determine whether preoxygenation with HFNO (30 to 70 L/min oxygen flow) via nasal prongs is as effective as the recommended preoxygenation using standard 15 L/min oxygen administered via a tight-fitting facemask in obstetric patients.
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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 | 0.004 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.003 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
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".