Journal of Clinical Toxicology

Journal of Clinical Toxicology
Open Access

ISSN: 2161-0495

+1 504 6082390

Derivation of cardiac output and alveolar ventilation rate based on energy expenditure measurements in healthy males and females

International Toxicology Summit & Expo

November 26-28, 2012 Hilton San Antonio Airport, USA

Pierre Brochu

AcceptedAbstracts: J Clinic Toxicol

Abstract :

P hysiologically 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 to 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 ( 2 H) and heavy-oxygen ( 18 O) in urine monitored by gas-isotope-ratio mass spectrometry. Arterioveinous oxygen content differences (0.051 to 0.082 ml of O 2 consumed/ml of blood) and ratios of the physiological dead space to the tidal volume (0.232 to 0.419) were determined for oxygen consumption rates (0.157 to 0.806 L/min) required by minute energy expenditures ranging from 0.76 to 3.91 kcal/min. Generally higher values for the 2.5 th up to 99 th percentile for VE (0.132 to 0.774 L/kg-min, 4.42 to 21.69 L/m 2 -min), VA (0.093 to 0.553 L/kg-min, 3.09 to 15.53 L/m 2 -min), Q (0.065 to 0.330 L/kg-min, 2.17 to 9.46 L/m 2 -min) and ventilation-perfusion ratios (1.12 to 2.16) were found in children and teenagers aged 5 to less than 16.5 years compared to 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