title: Derivation of cardiac output and alveolar ventilation rate based on energy expenditure measurements in healthy males and females.
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.
authors.affiliation: Ministère du Développement Durable, de l'Environnement et des Parcs, Direction du Suivi et de l'État de l'Environnement, Service des Avis et Expertises Scientifiques, Gouvernement du Québec, Édifice Marie-Guyart, 7e Étage, 675 Boulevard René-Lévesque Est, Québec, QC G1R 5V7, Canada. pierre.brochu@mddep.gouv.qc.ca
authors.forename: Pierre
authors.initials: P
authors.lastname: Brochu
authors.forename: Jules
authors.initials: J
authors.lastname: Brodeur
authors.forename: Kannan
authors.initials: K
authors.lastname: Krishnan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002153:Calorimetry, Indirect; D002302:Cardiac Output; D002648:Child; D002675:Child, Preschool; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000652:urine; D010101:Oxygen Consumption; D012016:Reference Values; D012119:Respiration; D014692:Ventilation-Perfusion Ratio / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen