Lung volume estimation

Body density (D0) is the ratio of body weight (BWg j.) to body volume. Body volume can be measured by water displacement or helium dilution, but the method of choice is underwater weighing (BWu2q) with corrections for the density of water (DHh2q) nd residual lung volume (RV) (40). Density is then estimated as follows ... 

Total lung deposition estimates were determined by Heyder et al. (1975) for nose and mouth breathers at various tidal volumes of air (Table 27.5). Their deposition estimates for nose breathers at tidal volumes of 250 and 500 cm demonstrate reasonable agreement with probabilistic deposition estimates for adult nose breathers the results are within a factor of 2. At increased tidal volumes of 1000 and 1500cm, however, their results do not compare well with this assessment s probabilistic estimates. This occurs due to the significantly reduced volumetric flow rates of air that they used, as compared to those employed by our theoretical estimates. As volumetric flow rate is increased, a reduction in particle deposition occurs in the lung region, due to the decreased residence time in the respiratory tract. 

In the Montreal case-control study carried out by Siemiatycki (1991) (see monograph on dichloromethane in this volume), the investigators estimated the associations between 293 workplace substances and several types of cancer. Isocyanates were one of the substances, and it was stated that the most common form in this study was toluene diisocyanates. The main occupations to which isocyanate exposure was attributed in this study were motor vehicle refinishers, motor vehicle mechanics and foundry workers. Only 0.8% of the study subjects had ever been exposed to isocyanates. For most types of cancer examined (oesophagus, stomach, colon, rectum, pancreas, prostate, bladder, kidney, skin melanoma, lymphoma), there was no indication of an excess risk due to isocyanates. For lung cancer, in the population subgroup of French Canadians (the majority ethnic group in this region), based on 10 cases exposed at any level, the odds ratio was 2.2 (90% CI, 0.9-5.3). [The interpretation of the null results has to take into account the small numbers and presumably low exposure levels. Workers had multiple exposures.]... 

A relatively accurate estimate can be made of inhalation contact exposure using the information on lung capacity and breathing rates (14). If it is assumed that an applicator occupies a space 2 metres square by 3 metres high, the immediate volume surrounding him would be 6000 litres. The concentration of pesticide that would be contained in this 6000 litres would be that which would impinge on the 2 square metres. For an application rate of 454 g.4047 m 2 the concentration in the 6000 litres would be ... 

From the activity in samples of venous blood, and the subject s estimated blood volume, the transfer of 203Pb from lung to blood could... 

The deposition estimates that Heyder et al. (1975) determined were at various tidal volumes for mouth breathers. Their deposition estimates for tidal volumes between 500 and 1500 cm are within a factor of 2 of this study s mean for probabilistic deposition in the total lung of mouth breathers. Our deposition fraction estimates are within a factor of 3 of the results determined by Heyder et al. (1975) for a Vj of 250 cm. ... 

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