PubMed · 6738445
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F Belosi. [Sampling technics: granulometric separators].. https://pubmed.ncbi.nlm.nih.gov/6738445/
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In recent years there has been a growing awareness of possible hazards caused by anaesthetic gases in operating theatres. Our study monitored ambient nitrous oxide (N2O) levels in the operating theatres and recovery rooms at the University Hospital in Tromsø. The results show that exposure to waste anaesthetic gases occurs because of leaks in the anaesthetic equipment. The three major sources of leaks are masks, high pressure fittings and exhalation valves. Prevention of leakage from equipment is very important, and a leakage testing programme should be an essential part of the daily control strategy. Good working practices and tracheal intubation results in low exposure to nitrous oxide in the breathing zone of the anesthetic personnel. During mask anaesthesia we have observed nitrous oxide concentrations above 1500 ppm, owing to mask leakage. A closely fitting scavenging mask and good working practices lead to in lower nitrous oxide concentrations. Nitrous oxide exhalation from the patient in the recovery room is only a minor problem.
Evidence from laboratory animals suggests that certain rates of deposition of dust can slow the normal clearance of the lungs by macrophages. If this occurs in humans, then estimates of exposure or dose for epidemiologic models may be improved by explicity incorporating this "overload" phenomenon into lung dose estimates. Using a model of dust overload, the authors estimated the lung dust dose for a group of workers exposed to silicon carbide dust. From a knowledge of underlying biologic mechanisms and using goodness of fit tests, the authors identified parameters for the dosimetric model that yielded dose estimates which fit the epidemiologic data well. The dosimetric estimates also compare favorably with cumulative exposure as risk predictors of radiographic evidence of pulmonary fibrosis. The evidence for overload is not strong, however, since the data are also consistent with other clearance patterns including very slow linear one-compartment clearance. Nevertheless, in some data sets, use of a dosimetric model instead of cumulative exposure to dust may reduce misclassification in exposure and improve fit to epidemiologic data. Furthermore, evidence of a better fit would provide valuable information about biologic mechanisms or aspects of dose such as the effect of short-term, high-intensity exposures. These in turn might provide information about prevention strategies such as standard setting.
Many risk assessments for leukemia associated with benzene exposure have been based on the mortality experience of the rubber hydrochloride worker cohort. Although there have been several different historical exposure assessments proposed for this cohort, Paustenbach et al. [1992, J Tox Environ Health], recently published a new historical characterization of benzene exposures based on data previously developed by Rinsky et al. [1981, Am J Ind Med] and further modified by Crump and Allen [1984: OSHA]. Adjustments by Paustenbach et al. in the Rinsky et al. data result in retrospective benzene exposure estimates far greater than those previously reported, by an order of magnitude in many cases. Judgments made on the significance of dermal contact and interpretation of historical measurement data led Paustenbach et al. to arrive at exposure estimates for this cohort that are in conflict with what is known about the adverse effects of benzene exposure. More reasonable estimates for dermal absorption are included in this report that do not substantially affect total estimates of benzene exposure for the cohort. The exposure estimates originally presented in the Rinsky et al. article appear in concordance with data not previously reported in any analyses.