High frequency oscillatory ventilation (HFOV) is an alternative method of ventilation that theoretically achieves the goals of lung protective ventilation. During HFOV, gas exchange occurs through the application of a constant mean airway pressure (mPaw) that is usually higher than that applied during conventional ventilation (CV). Theoretically, HFOV may lead to improved alveolar recruitment while avoiding both the cyclic closing and opening of alveolar units and the high peak airway pressures that occur with CV. The potential adverse effects of HFOV include cardiovascular compromise or barotrauma from the higher airway pressures. Read more »
News - Part 4
In this context, it has also to be discussed whether dust and fiber concentrations in our study are surrogate markers for nondetected exposures at the workplaces. It is well known that in the soft tissue paper-producing industry, a complex exposure situation exists. Moreover lung function impairment has been reported from other work sites with organic dust exposure outside the soft tissue paper-producing industry, eg, among cotton textile workers and poultry workers. Lung function impairment could be unspecifically related to the very high dust concentrations no matter what kind of dust exposure takes place (overload phenomenon). Read more »
The results of our study do not support the hypothesis that cellulose fiber exposure has a separate or specific effect on lung function. However, a clear separation of specific fiber and dust effects is not possible due to methodologic problems (different units). The interpretation has to take into account the fact that fibers are part of the total dust amount. The parameter estimates with relation to cumulative dust-years and fiber-years reveal similar results (Table 4). Read more »
It has been a matter of concern whether fiber shape of cellulose containing dusts might be responsible for health complaints and respiratory diseases with lung function impairment. Therefore, inhalable dust and fiber dust concentrations were determined in our study simultaneously. The results of the ambient monitoring revealed very high dust exposures for the inhalable dust fraction, whereas the respirable fraction was considerably low (Table 2). This might lead to the suggestion that in our study the potential for the detection of adverse effects on the lower respiratory tract could be small. Read more »
For FVC, a dose-dependent decrease from 105.4 to 96.9% predicted in the subgroup with highest cumulative dust exposure was observed (Table 3), This effect was also found with relation to cumulative fiber exposure (105.4% predicted and 97.1% predicted). The parameter estimates with relation to dust-years and fiber-years (Table 4) show clear dose-response relationships that are more pronounced compared to FEV1.
FEV1%FVC did not change significantly in the subgroups with different exposure intensity. The relation of both parameters slightly increased with increasing exposure intensity without reaching statistical significance (Tables 3, 4). Read more »
In a third step, odds ratios and p values for the clinically relevant threshold FVC < 80% predicted were calculated for the different exposure subgroups in a logistic regression model incorporating factory, age, sex, body mass index, and smoking habits. All reported p values are two sided, those < 0.05 were considered as significant. The statistical analyses were performed using the SPSS version 10 (SPSS; Chicago, IL) and SAS version 8.1 (SAS Institute; Cary, NC). there Read more »
From all subjects, information on occupational history, duration of exposure, workshop within the company, former occupational exposures, and smoking habits were available. Informed written consent was obtained from each participant.
Spirometry was performed with a Jaeger-Masterlab (two companies, n = 606) and a Jaeger Flowscreen (n = 441) [Jaeger-Toennies; Wurzburg, Germany] according to American Thoracic Society criteria. It included the measurement of the FVC and FEV1. Relative values were calculated for the measured lung function parameters by using the reference values proposed by the European Community for Coal and Steel. Read more »
The study group comprised all persons working in the production unit of nine randomly chosen companies. There was no selection based on exposure intensity, size of the factories, health complaints among employees, or other factors. Data were collected from 1,047 persons. According to the employers’ information, we examined all persons from the different workshops employed at the time period 1996/1998. However, we had no possibility to check the list of all persons employed and to compare them with the list of persons we examined. Characteristics of the study group are presented in Table 1. Read more »
In the pulp and paper-producing industry, workers are exposed to a wide variety of hazardous substances. Due to the possible adverse effects on human lungs, fiber-containing dusts are of special interest in occupational medicine. Animal experiments with cellulose fibers and cellulose fiber products (Isofloc; Okologische Bautechnik; Hess, Lichtenan, Germany) showed a relatively high biopersistence. Moreover, granulomatous pneumonia and minimal interstitial fibrosis as well as alveolar cell-type hyperplasia were found in rats.
In the literature, there is limited evidence for an increased prevalence of respiratory symptoms in paper workers. Some authors described adverse effects on lung function; however, the intensity and type of the reported effects have been inconsistent, While some authors found a more obstructive pattern, others described a decreased lung elastic recoil pressure and decreased residual volume. Due to multiple exposure to substances including chemicals, ozone, and fiber-containing dusts, the mechanisms that are responsible for these effects and the causal relationships with certain exposures could not yet be described. Read more »
As demonstrated in our study, virtual bronchoscopy may be used for the evaluation of both central and segmental airway stenosis. This enables the evaluation of the segmental airways distal to a stenosis, which is impassable for flexible bronchoscopy. Other potential clinical uses of virtual bronchoscopy include the planning of flexible bronchoscopy, the identification of abnormal airways and pathologic lymph nodes, and the follow-up of airway stenosis over time, in response to treatment, or in patients too ill to tolerate flexible bronchoscopy. Flexible bronchoscopy and virtual bronchoscopy should not be pitted against each other but, rather, should be used as complementary techniques. Read more »