Derivation of cardiac output and alveolar ventilation rate based on energy expenditure measurements in healthy males and females
Bibliographic record
Abstract
Physiologically based pharmacokinetic modeling and occupational exposure assessment studies often use minute ventilation rates (VE), alveolar ventilation rates (VA) and cardiac outputs (Q) that are not reflective of the physiological variations encountered during the aggregate daytime activities of individuals from childhood to adulthood. These variations of VE, VA and Q values were determined for healthy normal-weight individuals aged 5-96 years by using two types of published individual data that were measured in the same subjects (n = 902), namely indirect calorimetry measurements and the disappearance rates of oral doses of deuterium (²H) and heavy-oxygen (¹⁸O) in urine monitored by gas-isotope-ratio mass spectrometry. Arteriovenous oxygen content differences (0.051-0.082 ml of O₂ consumed ml⁻¹ of blood) and ratios of the physiological dead space to the tidal volume (0.232-0.419) were determined for oxygen consumption rates (0.157-0.806 l min⁻¹) required by minute energy expenditures ranging from 0.76 to 3.91 kcal min⁻¹. Generally higher values for the 2.5th up to the 99th percentile for VE (0.132-0.774 l kg⁻¹ min⁻¹, 4.42-21.69 l m⁻² min⁻¹), VA (0.093-0.553 l kg⁻¹ min⁻¹, 3.09-15.53 l m⁻² min⁻¹), Q (0.065-0.330 l kg⁻¹ min⁻¹, 2.17 to 9.46 l m⁻² min⁻¹) and ventilation-perfusion ratios (1.12-2.16) were found in children and teenagers aged 5-<16.5 years compared with older individuals. The distributions of cardiopulmonary parameters developed in this study should be useful in facilitating a scientifically sound characterization of the inter-individual differences in the uptake and health risks of lipophilic air pollutants, particularly as they relate to younger children.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".