Taux quotidiens d’inhalation et paramètres cardio-pulmonaires chez l’humain selon les données publiées en rapport au double marquage des molécules d’eau pour l’analyse du risque
The aim of the present study is to determine some respiratory and cardiovascular parameters in subjects of all ages for use, as physiological inputs, in toxicokinetic simulations and toxic risk assessment. The database used is taken from the literature. Data of interest include basal energy expenditures and total daily energy expenditures obtained by indirect calorimetry and doubly labeled water measurements respectively. Depending upon the unit value chosen, the highest 99th percentiles for daily inhalation rates were found in overweight/obese females 11 to 55 years old during their 36th weeks of pregnancy (47.31 m³/day), as well as in normal-weight boys aged 2.6 to less than 6 months(1.138 m³/kg-day) and 10 to less than 16.5 years (22.29 m³/m²-day). Generally higher values for the 2.5th up to 99th percentile were found in normal-weight children and teenagers aged 5 to less than 16.5 years compared to those for older individuals: minute ventilation rate, 0.132 to 0.774 L/kg-min or 4.42 to 21.69 L/m²-min versus 0.076 to 0.461 L/kg-min or 2.80 to 16.99 L/m²-min; alveolar ventilation rate, 0.093 to 0.553 L/kg-min or 3.09 to 15.53 L/m²-min versus 0.047 to 0.312 L/kg-min or 1.73 to 11.63 L/m²-min; cardiac output, 0.065 to 0.330 L/kg-min or 2.17 to 9.46 L/m²-min versus 0.045 to 0.201 L/kg-min or 1.63 to 7.24 L/m²-min; ventilation-perfusion ratio, 1.12 to 2.16 versus 0.78 to 2.40. Higher intakes of air pollutants by the respiratory tract expressed in ug/kg-min or ug/m²-min are expected in children compared to older individuals for identical exposure concentrations.The same conclusion is reached in pregnant and lactating females compared to male subjects of same ages, for intakes expressed per unit of bodyweight. The aggregate results obtained notably suggests that NOAELH values from Health Canada could be decreased by a factor of 2.6 by the use of the highest 99th percentiles for daily inhalation rates found in children; the minute ventilation rate of 20.83 L/min approximated based on an 8-hour workday may be considered as being conservative; however, the use of the daily inhalation rate of 0.286 m³/kg-day (i.e. 20 m³/day for a 70-kg adult) is inappropriate in risk assessment and management when applied to the whole population.
Inhalation Ventilation-perfusion Energy expenditure Oxygen consumption Inhalation Minute ventilation Alveolar ventilation Cardiac output Ventilation-perfusion Doubly labeled water Risk assessment