Estimated Pao 2: A Continuous and Noninvasive Method to Estimate Pao 2 and Oxygenation Index
Bibliographic record
Abstract
BACKGROUND: Pa o 2 is the gold standard to assess acute hypoxic respiratory failure, but it is only routinely available by intermittent spot checks, precluding any automatic continuous analysis for bedside tools. OBJECTIVE: To validate a continuous and noninvasive method to estimate hypoxemia severity for all Sp o 2 values. DERIVATION COHORT: All patients who had an arterial blood gas and simultaneous continuous noninvasive monitoring from 2011 to 2019 at Boston Children’s Hospital (Boston, MA) PICU. VALIDATION COHORT: External cohort at Sainte-Justine Hospital PICU (Montreal, QC, Canada) from 2017 to 2020. PREDICTION MODEL: We estimated the Pa o 2 using three kinds of neural networks and an empirically optimized mathematical model derived from known physiologic equations. RESULTS: We included 52,879 Pa o 2 (3,252 patients) in the derivation dataset and 12,047 Pa o 2 (926 patients) in the validation dataset. The mean function on the last minute before the arterial blood gas had the lowest bias (bias –0.1% validation cohort). A difference greater than or equal to 3% between pulse rate and electrical heart rate decreased the intraclass correlation coefficients (0.75 vs 0.44; p < 0.001) implying measurement noise. Our estimated Pa o 2 equation had the highest intraclass correlation coefficient (0.38; 95% CI, 0.36–0.39; validation cohort) and outperformed neural networks and existing equations. Using the estimated Pa o 2 to estimate the oxygenation index showed a significantly better hypoxemia classification (kappa) than oxygenation saturation index for both Sp o 2 less than or equal to 97% (0.79 vs 0.60; p < 0.001) and Sp o 2 greater than 97% (0.58 vs 0.52; p < 0.001). CONCLUSION: The estimated Pa o 2 using pulse rate and electrical heart rate Sp o 2 validation allows a continuous and noninvasive estimation of the oxygenation index that is valid for Sp o 2 less than or equal to 97% and for Sp o 2 greater than 97%. Display of continuous analysis of estimated Pa o 2 and estimated oxygenation index may provide decision support to assist with hypoxemia diagnosis and oxygen titration in critically ill patients.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 | 0.013 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".