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.

Changes in the negative logarithm of end-tidal hydrogen partial pressure indicate the variation of electrode potential in healthy Japanese subjects

“…H 2 is not directly involved in cellular metabolism, and its transport has not been thoroughly investigated 43 . Some of the H 2 produced by the microbiome is absorbed into the blood, and dissolved H 2 diffuses into the alveolar air according to the Bunsen absorption coefficient (1.8 mL of H 2 /100 mL of water at 1 bar) and the ventilation-perfusion ratio (1.35 ± 0.22), which is the ratio of alveolar air (ℓ) per blood (ℓ) in normal-weight individuals aged 25–34 years 44 . As a result, the dissolved H 2 will be diluted approximately 75 times in the gas phase.…”

Physiological Daily Inhalation Rates for Health Risk Assessment in Overweight/Obese Children, Adults, and Elderly

“…The RQ value may be determined by a complete diet record over the duration of the study or respiratory gas‐exchange measurements (RQ = CO 2 produced /O 2 consumed ). The basic principles of indirect calorimetry and the DLW method are summarized in Brochu et al . Body weight (kg), height (cm), and BMI (kg/m 2 ) values complete the set of data (with BEE and TDEE) that are systematically measured in the same subjects during the DLW method.…”

Cardiopulmonary values and organ blood flows before and during heat stress: data in nine subjects at rest in the upright position

“…to 28.9 cal/kg-min that have been measured during the aggregate daytime activities of freeliving individuals of 16.5 to less than 35 years old (Brochu et al 2012) 0, 7.8, 8.2, 15.8, 18.5. 21.9 and 44.3%), whereas the other had a decrease in RR (by 12.4%).…”

“…In previous publications (Brochu et al 2011(Brochu et al , 2012(Brochu et al , 2014Brochu and Facetti Socol 2016), values for the minute energy expenditure rate (E) and cardiopulmonary parameters have been determined during the aggregate daytime activities of free-living individuals by using two types of published individual data. These values were measured in the same subjects by indirect calorimetry measurements and disappearance rates of oral doses of deuterium…”