Comparison of tissue oxygenation achieved breathing oxygen using different delivery devices and flow rates
Bibliographic record
Abstract
Introduction: Divers with suspected decompression illness require high concentration oxygen (O2). There are many different O2 delivery devices, with few data comparing their performance. This study evaluated O2 delivery, using tissue O2 partial pressure (PtcO2), in healthy divers breathing O2 via three different delivery devices. Methods: Twelve divers had PtcO2 measured at six limb sites. Participants breathed O2 from: a demand valve using an intraoral mask with a nose clip (NC); a medical O2 rebreathing system (MORS) with an oronasal mask and with an intraoral mask; and a non-rebreather mask (NRB) at 15 or 10 L·min-1 O2 flow. In-line inspired O2 (FIO2) and nasopharyngeal FIO2 were measured. Participants provided subjective ratings of device comfort, ease of breathing, and overall ease of use. Results: PtcO2 values and nasopharyngeal FIO2 were similar with the demand valve with intraoral mask, MORS with both masks and the NRB at 15 L·min-1. PtcO2 and nasopharyngeal FIO2 values were significantly lower with the NRB at 10 L·min-1. The NRB was rated as the most comfortable to wear, easiest to breathe with, and overall the easiest to use. Conclusion: Of the commonly available devices promoted for O2 delivery to injured divers, similar PtcO2 and nasopharyngeal FIO2 values were obtained with the three devices tested: MORS with an oronasal or intraoral mask, demand valve with an intraoral mask and NRB at a flow rate of 15 L·min-1. PtcO2 and nasopharyngeal FIO2 values were significantly lower when the flow rate using the NRB was decreased to 10 L·min-1.
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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 | 0.000 | 0.000 |
| 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".