Validation of Pulse Oximetry During Progressive Normobaric Hypoxia Utilizing a Portable Chamber
Bibliographic record
Abstract
Validation of pulse oximetry in commercially available normobaric hypoxic chambers (NHC) has not been previously reported. The present study examined the validity of pulse oximetry (SpO2) against direct measurements of arterial oxygen saturation (SaO2) via co-oximetry (AVOXimeter 4000) in 13 young adults age 21.3 +/- 0.6 years. Over a period of 2.5 hrs, the inspired fraction of oxygen inside a NHC (Hypoxico, Inc.) was progressively reduced from 20.9% to 11.5%. Measurements of SaO2 at baseline and at 15, 30, 60, 90, 120, and 150 min during the hypoxic exposures were compared with SpO2 estimates of oxygen saturation (Nellcor 295) using reflectance (RS-10, temporal) and transmission (D-25, finger) sensors. Regression analysis and methods for assessing agreement (bias, b; precision, p) of SaO2 with SpO2 were similar (R2 = 0.92, 0.89; b = 0.016, -0.47; p = 2.47, 3.03; RS-10 and D-25, respectively). When SaO2 < 85%, RS-10 had greater validity than D-25 (R2 = 0.73, 0.56; b = 1.38, 1.13; p = 2.72, 4.34; RS-10 and D-25, respectively). In light of these findings, caution should be exercised when monitoring individuals with pulse oximetry during desaturation episodes below 85%. When employing frequent NHC exposures, a priori validation of SpO2 utilized to assess blood oxygen status appears warranted.
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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 | 0.002 | 0.006 |
| 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 | 0.001 | 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 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".