Assessment of Bohr and Enghoff Dead Space Equations in Mechanically Ventilated Children
Bibliographic record
Abstract
BACKGROUND: Recent findings suggest that using alveolar P CO 2 (P ACO 2 ) estimated by volumetric capnography in the Bohr equation instead of P aCO 2 (Enghoff modification) could be appropriate for the calculation of physiological dead space to tidal volume ratio (V D /V T Bohr and V D /V T Enghoff , respectively). We aimed to describe the relationship between these 2 measurements in mechanically ventilated children and their significance in cases of ARDS. METHODS: From June 2013 to December 2013, mechanically ventilated children with various respiratory conditions were included in this study. Demographic data, medical history, and ventilatory parameters were recorded. Volumetric capnography indices (NM3 monitor) were obtained over a period of 5 min preceding a blood sample. Bohr's and Enghoff's dead space, S2 and S3 slopes, and the S2/S3 ratio were calculated breath-by-breath using dedicated software (FlowTool). This study was approved by Ste-Justine research ethics review board. RESULTS: Thirty-four subjects were analyzed. Mean V D /V T Bohr was 0.39 ± 0.12, and V D /V T Enghoff was 0.47 ± 0.13 ( P = .02). The difference between V D /V T Bohr and V D /V T Enghoff was correlated with P aO 2 /F IO 2 and with S2/S3. In subjects without lung disease (P aO 2 /F IO 2 ≥ 300), mean V D /V T Bohr was 0.36 ± 0.11, and V D /V T Enghoff was 0.39 ± 0.11 ( P = .056). Two children with status asthmaticus had a major difference between V D /V T Bohr and V D /V T Enghoff in the absence of a low P aO 2 /F IO 2 . CONCLUSIONS: This study suggests that V D /V T Bohr and V D /V T Enghoff are not different when there is no hypoxemia (P aO 2 /F IO 2 > 300) except in the case of status asthmaticus. In subjects with a low P aO 2 /F IO 2 , the method to measure V D /V T must be reported, and results cannot be easily compared if the measurement methods are not the same.
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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) | 0.000 | 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 | 0.000 | 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".