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Results for “Respiratory Protective Devices”

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At least 37 records · Page 2Linked to original sources
PubMed1991

Psychological effects on prolonged use of respiratory protective devices in children.

In the study of psychological effects of prolonged use of a respiratory protective device (RPD), forty 7-10-year-olds, fifty 12-15-year-olds and twenty-eight 17-20-year-olds participated as subjects. Subjects in the experimental groups wore a full-face mask provided for civil defence in Sweden, and subjects in the control groups wore a filtering facepiece consisting of a tissue material covering the nose and mouth. Subjects in both groups tended to terminate at the same time, implying that breathing resistance may not be an important obstacle to prolonged wear of the full-face mask. In the experimental groups 97% wore the mask for at least 1.5 h, 77% for at least 2.5 h and 54% for the full 6-h session. About 50% of subjects in the younger age groups terminated in the interval between 1.5 to 3.5 h, whereas the corresponding figure in the older age group was about 30%. Boredom may have played an important role for decisions to terminate, perhaps in part because the mask interfered with speech communication. Discomfort due to pressure on the nose, the chin and the forehead was also reported, more frequently by the older than by the younger subjects.

Adolescent↗
PubMed1993

Respiratory health status in swine producers using respiratory protective devices.

A cross-sectional survey on respiratory health in swine producers showed that 30% of 301 examined men usually used a dust mask when working inside a barn. They did not differ significantly from dust mask nonusers in respect to respiratory symptoms and lung function. This analysis was undertaken to determine whether the respiratory health of dust mask users was associated with reasons why they had started individual respiratory protection. The subjects were recontacted in order to identify those who started using a mask to deliberately prevent symptoms (42 men) and those who started protection because of pre-existing respiratory symptoms (44 men). Not unexpectedly, between-group comparisons of respiratory symptoms and lung function suggest that swine producers who wear dust masks for preventive purposes have better respiratory health than those who wear dust masks because of symptoms or those who do not use individual respiratory protection. The individual reasons for starting dust mask usage should be examined among potential determinants of the outcomes of prospective studies which can then provide more valid assessment of the effect of individual respiratory protection.

Adult↗
PubMed2004

Evaluation of CO2 accumulation in respiratory protective devices.

A simple mathematical model was developed to grade the results of the fraction of inspiratory CO2 levels in respiratory protective devices (RPDs). Using this model, the level of FiCO2 of two chemical warfare RPDs was monitored during the examination of 54 young male volunteers at rest and exercise. No set of results distributed in a normal Gaussian mode; therefore, parametric statistics could not be used to analyze the group's results. Yet the model allowed simple and insightful evaluation of the results, stressing differences between the similar RPDs. We suggest continued use of the analysis model as a tool for quantitative evaluation of results and further understanding of the respiratory patterns of RPDs.

Adult↗
PubMed1993

The effect of evaporative cooling of respiratory protective devices on skin temperature, thermal sensation, and comfort.

High skin temperature of the face is a major source of discomfort while wearing respiratory protective devices. In this paper theoretical considerations of thermal exchange between the face and the environment with and without a mask are discussed to elucidate factors that may improve the design of masks to increase their acceptability. Comfort thresholds have been related to skin temperature for both resting and exercising subjects. Skin temperature below 34.5 degrees C at rest, and 31 degrees C during exercise, is rated as comfortable. In a previous study it was determined that evaporative cooling could reduce skin temperature and decrease discomfort in a dummy mask. In the present study evaporative cooling of a more sophisticated dummy mask and a modified Scott model 66 twin-cartridge respirator was tested in resting and exercising subjects. Skin temperature was significantly reduced when wet felt covered the surface of both masks and at rest the masks were rated as significantly more comfortable than with dry felt on the outer surface. It is concluded that evaporative cooling of an existing face mask can reduce skin temperature to the comfort threshold in resting subjects. Data suggest that similar results are attainable for exercising subjects.

Adult↗
PubMed1992

The effects of powered air supply to the respiratory protective device on respiration parameters during rest and exercise.

The common chemical warfare protective masks impose an excessive respiratory load on the wearer due to elevated breathing resistance and increased dead space. For patients with severe respiratory disease, the excessive respiratory effort may be intolerable. Besides, the substantial negative pressure created within the mask during inspiration may result in an inward leakage in individuals having difficulties with proper facial fitting of the mask. The purpose of the current investigation was to evaluate the effects of a blower, actively driving air, through the mask's filter, at a flow (mean +/- SD) of 42 +/- 2 L/min, on respiratory parameters during rest and moderate exercise. Ten healthy subjects of either sex participated in two experimental sessions, wearing the mask with and without the blower. Each session included 6 min of sitting at rest and 6 min of walking on a treadmill (3.2 mph, and 10 percent grade). In nine of the subjects, the active air supply produced a positive inspiratory pressure at rest (5 +/- 4 vs -24 +/- 9 mm H2O peak inspiratory pressure with and without the blower, respectively, p < 0.0001). Inspiratory carbon dioxide concentration (FICO2) at rest was diminished (0.4 +/- 0.4 vs 1.3 +/- 0.7 percent with and without the blower, respectively; p < 0.01) while FIO2 increased from 19.5 +/- 0.7 percent to 20.6 +/- 0.4 percent with the device (p < 0.01). These changes were associated with a significant decrease in respiratory rate (15 +/- 2 vs 18 +/- 3 per minute, p < 0.01). During exercise the blower barely decreased the negative inspiratory pressures, had no effect on other respiratory parameters measured, but significantly shortened the inspiratory/cycle-length time ratio (0.46 +/- 0.03 vs 0.53 +/- 0.03, p < 0.005). The effects of active air supply were not different between male and female subjects. We conclude that the blower is expected to be a useful accessory to respiratory protective devices for patients with pulmonary disease.

Adult↗
PubMed1985

Individual factors in the choice of respiratory protective devices.

Federal regulations recognize the need to determine whether individuals are physically able to perform their job while wearing respirators. A variety of safety and workplace factors should also be considered at the time that a respiratory protective device is evaluated for use by a particular worker. In most negative pressure respirators, inspiratory resistance constitutes the major load on the respiratory system. In normals, the major load to the cardiovascular system occurs with heavy, self-contained respirators. In the absence of objective guidelines for the use of respirators by impaired workers, careful examination and conservative clinical judgement, and the willingness to re-assess choices must form the basis of respirator selection.

Humans↗
PubMed2005

Deposition and resuspension of selected aerosols particles on electrically charged filter materials for respiratory protective devices.

The primary aim of the study was to analyse the non-steady state of filtration for selected electrostatic filter materials designed for use in respiratory protective devices. The obtained results showed that the filtration process in electrostatic filters was dependent in the main on the following factors: type of the filter material, electrostatic field strength of the material, and the charge of the aerosol. To a lesser degree the filtration process depended on the sign of the charge and the relative humidity of the air. A significant correlation was found between the increase in the penetration and the decrease in breathing resistance while the filter was being loaded. The effect of resuspension (tearing off and re-deposition of dust agglomerates inside the filter) on the filtration process very significant. It was also observed that under certain conditions electrostatic filter materials lost their protection properties.

Aerosols↗
PubMedDate not supplied

The role of respiratory protective devices in the control of tuberculosis.

In this comprehensive review, the authors describe various types of respirators and the major issues in their application to TB control, including the degree of protection they offer and cost. Recent recommendations regarding the use of respiratory protective devices also are discussed.

Equipment and Supplies↗
PubMed1999

Respiratory protective devices: rates of medical clearance and causes for work restrictions.

BACKGROUND: There are no published data on the outcomes and benefits of medical evaluations for the use of respiratory protective devices. We, therefore, conducted a retrospective database and chart review to assess the rates of medical clearance and causes for work restrictions at a Department of Energy complex. METHODS: All workers with work restrictions or denied clearance over a one-year period were identified and their medical records abstracted. RESULTS: Of the 5,569 workers who received medical evaluation, only 71 (1.3%) received limitations on respirator use documented in their medical record. Of the 65 workers with sufficient medical records for additional analysis, 9 of the 5,569 workers (0.2%) were denied medical clearance, while 56 workers (1.1%) received work restrictions. Pregnancy was the most common cause for denying medical clearance for respirator use. Lung disease, cardiovascular disease, and claustrophobia were the most common causes for work restrictions. Physical examination and spirometry added little to the detection of relevant medical conditions. CONCLUSIONS: We conclude that few workers fail medical clearance for respirator use or receive work restrictions. Data on adverse events from respirator use are needed to help design appropriate medical evaluations and uniform criteria for work restrictions or denial of medical clearance.

Adult↗
PubMed2000

Personal respiratory protective devices: efficacy of intranasal stent with filters.

Intranasal, hollow, cylindrical, medical grade and silicone stent with two outer layers face mask filters at both ends was proposed for atmospheric suspended particulate matter prevention. The personal respiratory protective device efficacy was done at the Otolaryngology Department, Ramathibodi Hospital from April 1996 to October 1997. Single pulse mode of carbon dioxide laser smoke particle was the suitable source of atmospheric suspended particulate matter. A laser plume evacuator removed laser smoke particles with 5 Millipore filters of 0.22 um pore size or 5 intranasal stent with filters attached at the inlet end. A Millipore filter got the same laser smoke particle amount that passed through each intranasal stent filter with an air flow rate of 15 l/min controlled by a rotameter. Laser smoke particle deposition in filter materials was counted under a high power optical microscope. Laser smoke particle amount in each layer of a four-layer filter of intranasal stent with 7.5, 15.0 and 30.0 l/min air flow rates is shown. The filtration efficacy of four, three and two layers of intranasal stent with a filter for laser smoke particle retention were compared. An intranasal stent with filter could be applied in a human nasal vestibule with acceptable air flow resistant during public transportation in a traffic congested area.

Environmental Pollution↗
PubMed1996

Veterinary practice and occupational health. An epidemiological study of several professional groups of Dutch veterinarians. II. Peak expiratory flow variability, dust and endotoxin measurements, use of respiratory protection devices, and time distribution of professional activities.

Dust and endotoxin exposure was measured in the Spring and Autumn in 96 veterinary practitioners, subdivided in four professional groups ((predominantly working with either swine, cattle, poultry, or companion animals). Furthermore, peak expiratory flow (PEF) variability was measured four times a day over a week in Spring and Autumn in order to detect occupation-related respiratory disorders. The participants kept a log book in which they recorded their activities during these periods. Practitioners working with swine, cattle, or poultry had a significantly higher exposure to dust (+/- 5 times) and endotoxin (+/- 10 times) than companion animal practitioners. PEF variability measurements gave no indications for an increased prevalence of bronchial hyperreactivity related to occupational activities. Respiratory protective devices (RPD) were used selectively. Only a small proportion of the practitioners used them at any time when entering a animal confinement building. Swine and cattle practitioners worked for approximately 3.6 hours per day in animal buildings, whereas poultry practitioners worked in the environment of poultry buildings for approximately 2.8 hours per day.

Animals↗
PubMed2000

Personal respiratory protective devices: efficacy of Millipore and Whatman filters.

A Millipore filter with 0.22 micron pore size and a Whatman grade 1 filter with > 11 microns particle retention were used to capture laser smoke particle mimic atmospheric suspended particulate matter. The experiment was conducted at the Department of Otolaryngology in Ramathibodi Hospital from April 1996 to October 1997. The laser smoke particle evacuator with rotameter created an air flow rate of 15 l/min through the filters. The mean and standard deviation of the laser smoke particle count under high power optical microscope in a 10 Millipore filter and a 10 Whatman filter were 411,327.6 +/- 13,325.0 and 290,453.0 +/- 28,409.8 respectively, 29.4 per cent different. Laser smoke particle size distribution in both filters under eyepiece micrometer was: 1 to 10 microns in Millipore (99.0%) and in Whatman (96.2%), 1 to 5 microns in Millipore (77.1%) and in Whatman (77.6%), no laser smoke particle larger than 17 microns was detected. The Millipore filter ruptured when the air flow rate was greater than 15 l/min. The Whatman filter was suitable for evaluating filtration efficacy of various personal respiratory protective devices in a high air flow rate condition.

Environmental Pollution↗
PubMed2002

Effect of respiratory protective devices on development of antibody and occupational asthma to an acid anhydride.

STUDY OBJECTIVES: To determine whether the use of respiratory protective equipment would reduce the incidence of occupational asthma due to exposure to hexahydrophthalic anhydride (HHPA). DESIGN: Prospective cohort study. SETTING: A facility that makes an epoxy resin product requiring HHPA for its manufacture. PARTICIPANTS: Sixty-six individuals newly hired at a facility that makes an epoxy resin product requiring HHPA for its manufacture. INTERVENTION: Employees who wished to use respiratory protective equipment could choose from three types of masks: dust mask, half-face organic vapor respirator, or full-face organic vapor respirator. MEASUREMENTS: Workers were evaluated annually for development of positive antibody to HHPA and occupational, immunologic respiratory disease, including occupational asthma. RESULTS: With use of respiratory protective equipment, the rate of developing an occupational immunologic respiratory disease was reduced from approximately 10 to 2% per year. Occupational asthma developed in only three individuals, and they were all in the higher exposure category. Statistically, one respirator was not superior to the others. CONCLUSION: Respiratory protective equipment can reduce the incidence of occupational immunologic respiratory disease, including occupational asthma, in employees exposed to HHPA.

Adult↗