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PubMed1988

Experiments supporting the use of ambient aerosols for quantitative respirator fit testing.

Most methods for testing facial seal leakage on subjects undergoing respirator fit tests involve comparing the generated aerosol particulate concentration inside the subject's respirator to the concentration in a test chamber. These aerosols are produced by fogging substances such as corn oil, dioctyl sebacate, or dioctyl phthalate (DOP) into the test chamber. The health effects of these substances and of their aerosols on respiratory systems are uncertain. The proposed alternate method uses as a test medium ambient particles which exist in most room atmospheres. The proposed method eliminates the need for a test chamber and for an intentionally produced aerosol. The subject is tested for respirator inleakage by comparing the particulate count concentration inside the subject's respirator to that of the room atmosphere outside the respirator. This method is less expensive and simpler to administer than the use of oil or other deliberately produced aerosols because it uses an existing ambient test medium. Statistical analysis of the test data indicates favorable comparison with the conventional chamber-aerosol method.

Aerosols↗
PubMed1990

Utilization of masks by Hutterite farmers.

Respiratory symptomatology and pulmonary function tests were evaluated among 199 male Hutterites who utilized masks during farming and 159 Hutterites who did not use masks. Anthropometric and pulmonary function tests were comparable between the two groups. Symptomatology, including cough, phlegm, and wheezing were more prevalent among mask wearers compared to non-mask wearers. The prevalence of hayfever (p less than 0.02) and asthma (p less than 0.001) was greater among mask wearers vs non-mask wearers. Although the types and percent of individuals from each group raising crops and livestock were comparable, breathlessness, wheeze and fever were more common among the mask wearers. Thus farmers who suffered a higher incidence of symptoms as a consequence of farming are more likely to use masks.

Adult↗
PubMed1990

Physiological effects of inspiratory resistance on progressive aerobic work.

The purpose of this study was to determine the potential effects on progressive aerobic work while breathing through a new military type chemical and biological (CB) respirator loaded with three different types of purifying canisters. Twelve healthy well-motivated male subjects (mean age 23 +/- 3 years) participated in the study. Results indicated that mean maximal oxygen uptake (VO2max), time to exhaustion, respiratory exchange ratio, rate of perceived exertion, respiratory rate and tidal volume at exhaustion, maximal lactate and the 2-min post-exercise lactate were not significantly influenced when breathing with the respirator and the canisters in comparison to a laboratory valve. Mean pulmonary ventilation, however, was reduced by 21% while oxygen and carbon dioxide ventilatory equivalents were significantly lower by 9% and 8% respectively. Review of the stage-by-stage responses to the treadmill test between the laboratory valve and respirator/canister conditions indicated no significant differences (NS) in oxygen uptake but slightly lower heart rates (NS). Ventilation was not influenced by the canisters until 80% of VO2max at which time the mean oxygen ventilatory equivalent became significantly lower. Blood lactate was significantly depressed between 60% and 90% VO2max under the respirator/canister conditions. It was concluded that, although physiological adaptation occurred, breathing with the new CB respirator and each of the three purifying canisters had no detrimental effect on progressive aerobic work to exhaustion. However, prolonged work at intensities greater than 80-85% of VO2max would in all probability be impaired when breathing with the CB mask and the canisters.

Adult↗
PubMed2006

Effect of respirators equipped with particle or particle-and-gas filters during exposure in a pig confinement building.

OBJECTIVES: This study compared the protective effect of two respiratory protection devices during exposure in a pig confinement building. METHODS: Thirty-six healthy persons were exposed for 3 hours in the building, 12 without any protection, 12 with a particle-filter mask, and 12 with a mask filtering both particles and gases. Symptoms, body temperature, nasal lavage fluid, exhaled nitric oxide, and bronchial responsiveness to methacholine were assessed before and after the exposure. Pre- and postexposure urine and blood samples were collected. RESULTS: After the exposure, the participants with respirators reported fewer symptoms than those without. Wearing a mask also reduced the inflammatory response assessed with nasal lavage (cell concentration, interleukins 6 and 8) and peripheral blood (cell number). Lung function was significantly impaired only in the unprotected group; postexposure vital capacity and forced expiratory volume in 1 second showed a decrease of 3-4% from the preexposure levels (P=0.006 and P=0.002, respectively). Bronchial responsiveness (P<0.01) and body temperature (P<0.001) increased similarly in the three groups. Bronchial responsiveness to methacholine increased 2.7, 2.4, and 2.1 doubling concentration steps for those unprotected, those using a particle-filter mask, and those using a mask with particle and gas filters, respectively. The prostaglandin D2 metabolite, 9a, 11b-PGF2 increased significantly (P=0.003) only in those unprotected. CONCLUSIONS: Wearing a respirator in a pig confinement building reduces the inflammatory reaction but does not influence the increase in bronchial responsiveness, with no difference between the use of a particle-filter mask or a mask with a particle-gas filter combination.

Adult↗
PubMed2002

[Personal protection against biological warfare agents].

Exposure to biological warfare agents may occur in several ways, the most prominent being aerosol infection, droplet infection, common component infection and via physical contact. These agents may enter the body through the respiratory tract, mucous membranes and through the skin. The mechanism of exposure and the route of entry of the specific agent will dictate the appropriate protection required. Available protective equipment include respiratory protective devices, full face protective masks and surgical masks for respiratory protection, battle dress overgarments, protective gloves and overboots for skin protection. Full protection is needed when the agent has not been identified. When the biological agent is known, the protective measures should be determined by its characteristics. Protection may include several levels of precautions: standard risk, aerosol infection, droplet infection and contact infection. This paper describes the routes of exposure to biological warfare agents, the available protective equipment and the precautions needed when treating biowarfare casualties.

Biological Warfare↗
PubMed1999

Evaluation of a novel protective gas mask during medical unit activity.

Evaluation of a battalion medical unit drill in a chemical warfare environment was carried out by comparing two respiratory protective devices: a new protective device (the Chemical Team Respirator) and the mask currently used in the Israel Defense Forces (the M-15). After a medical deployment drill conducted with 24 participants and 14 inspectors, comfort, communication, and various aspects of activity were evaluated by structured questionnaires. The new device, consisting of a hood, nose cup, and air blower system, was found to be preferable to the M-15 mask for physical and respiratory comfort, quality of visual field, and performance. The communication capabilities of the unit members, on the other hand, were severely limited by the hearing reduction caused by the hood of the new protective device. We conclude that the new device proved superior to the current mask by facilitating better performance of the team at the drill. Interference with hearing must be dealt with technically or bypassed by modifications in the unit's mode of communication.

Adolescent↗
PubMed1975

Mask design considerations.

Mask design should be based more strongly on physiological data obtained from working individuals. This paper is a compendium of pertinent information as well as a guide to better design. An indication of the trends of current research is also given.

Adaptation, Physiological↗
PubMed1980

[Contact allergy to N-isopropyl N'-phenylparaphenylenediamine (IPPD) in different individual protective devices (author's transl)].

N-isopropyl N'-phenylparaphenylenediamine, a known sensitizer, is searched for in different elastomeric formulations. Systematic chemical analysis as well as clinical investigations have been performed, especially on gloves, boots and respiratory protective devices. Some cases remain unaccounted for: some IPPD-sensitized people do not react to the contact of objects containing IPPD, other react to objects in which even thorough analysis failed to detect this compound. A better knowledge of the allergologic profile of sensitized people and better analytical detection limits might be desirable.

Dermatitis, Atopic↗
PubMed2004

Guidelines for preventing health-care--associated pneumonia, 2003: recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee.

This report updates, expands, and replaces the previously published CDC "Guideline for Prevention of Nosocomial Pneumonia". The new guidelines are designed to reduce the incidence of pneumonia and other severe, acute lower respiratory tract infections in acute-care hospitals and in other health-care settings (e.g., ambulatory and long-term care institutions) and other facilities where health care is provided. Among the changes in the recommendations to prevent bacterial pneumonia, especially ventilator-associated pneumonia, are the preferential use of oro-tracheal rather than naso-tracheal tubes in patients who receive mechanically assisted ventilation, the use of noninvasive ventilation to reduce the need for and duration of endotracheal intubation, changing the breathing circuits of ventilators when they malfunction or are visibly contaminated, and (when feasible) the use of an endotracheal tube with a dorsal lumen to allow drainage of respiratory secretions; no recommendations were made about the use of sucralfate, histamine-2 receptor antagonists, or antacids for stress-bleeding prophylaxis. For prevention of health-care--associated Legionnaires disease, the changes include maintaining potable hot water at temperatures not suitable for amplification of Legionella spp., considering routine culturing of water samples from the potable water system of a facility's organ-transplant unit when it is done as part of the facility's comprehensive program to prevent and control health-care--associated Legionnaires disease, and initiating an investigation for the source of Legionella spp. when one definite or one possible case of laboratory-confirmed health-care--associated Legionnaires disease is identified in an inpatient hemopoietic stem-cell transplant (HSCT) recipient or in two or more HSCT recipients who had visited an outpatient HSCT unit during all or part of the 2-10 day period before illness onset. In the section on aspergillosis, the revised recommendations include the use of a room with high-efficiency particulate air filters rather than laminar airflow as the protective environment for allogeneic HSCT recipients and the use of high-efficiency respiratory-protection devices (e.g., N95 respirators) by severely immunocompromised patients when they leave their rooms when dust-generating activities are ongoing in the facility. In the respiratory syncytial virus (RSV) section, the new recommendation is to determine, on a case-by-case basis, whether to administer monoclonal antibody (palivizumab) to certain infants and children aged <24 months who were born prematurely and are at high risk for RSV infection. In the section on influenza, the new recommendations include the addition of oseltamivir (to amantadine and rimantadine) for prophylaxis of all patients without influenza illness and oseltamivir and zanamivir (to amantadine and rimantadine) as treatment for patients who are acutely ill with influenza in a unit where an influenza outbreak is recognized. In addition to the revised recommendations, the guideline contains new sections on pertussis and lower respiratory tract infections caused by adenovirus and human parainfluenza viruses and refers readers to the source of updated information about prevention and control of severe acute respiratory syndrome.

Adenovirus Infections, Human↗
PubMed1982

Protecting workers who clean up hazardous waste sites.

On April 21, 1980, an explosion and fire among the 40 000 drums of unlabeled chemical wastes at the former site of Chemical Control Corporation in Elizabeth, New Jersey, attracted national attention and raised serious concern about the health and safety of workers who would be called upon to clean up the disaster site. Evaluation of workers' exposure during clean up operation and an assessment of the level of respiratory protection needed were necessary. NIOSH conducted 8 days of air monitoring. The chemicals of concern were organic vapors, metals, pesticides, polychlorinated biphenyls, cyanide compounds, and dioxins (TCDD). No excessive exposure to chemical substances by inhalation was found. However, continuous use of respiratory protective equipment and other personal protective devices was necessary because of frequent drum ruptures.

Air Pollutants↗
PubMed1978

Quantitative fit testing of personnel utilizing a mouthpiece respirator.

A respirator test facility using Refrigerant 12 as a challenge gas has been developed. More than 6000 people have received training in the effective use of mouthpiece respirators. Leakage is determined by the use of a halide detection meter analyzing the exhaled breath. The facilities have been used to provide training and quantitative fit testing for practically all types of respiratory protective equipment. An actual use investigation was made to determine the suitability of the mouthpiece respirator for use in a chlorine producing plant work situation. The mouthpiece respirator was compared with a group of half-face respirators. A clear distinction was made: the half-face respirator offered less protection than the mouthpiece respirator.

Chemical Industry↗
PubMed2006

Lung function in Pakistani wood workers.

The lung function impairment is the most common respiratory problem in industrial plants and their vicinity. Therefore, the purpose was to study the affects of wood dust and its duration of exposure on lung function. This was a matched cross-sectional study of Spirometry in 46 non-smoking wood workers with age range 20 - 60 years, who worked without the benefit of wood dust control ventilation or respiratory protective devices. Pulmonary function test was performed by using an electronic Spirometer. Significant reduction was observed in the mean values of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), and Maximum Voluntary Ventilation (MVV) in wood workers relative to their matched controls. This impairment was increased with the duration of exposure to wood industries. It is concluded that lung function in wood workers is impaired and stratification of results shows a dose-response effect of years of wood dust exposure on lung function.

Air Pollutants, Occupational↗
PubMed2004

Dose responses of years of exposure on lung functions in flour mill workers.

Flour dust is a heterogeneous substance with respiratory sensitizing properties; its long-term exposure may cause acute or chronic respiratory diseases. Therefore, the aim was to investigate the dose response effects of flour dust on lung function. An additional objective was to minimize the potential health risks in flour mill workers by providing them with information about the hazards of flour dust. Pulmonary function was studied in forty-six male flour mill workers who worked without the benefit of flour dust control ventilation or respiratory protective devices and a similar number of male control subjects. All participants were non-smokers and were matched for age, height, weight and socio-economic status. Pulmonary function tests were performed by using an electronic Spirometer and results were compared by a paired t-test. The present study results showed a significant decrease in the mean values of FVC, FEV(1), PEF and MVV and this impairment was increased with duration of exposure in the flour mills. This group of flour mill workers had occupationally related pulmonary function impairment and stratification of results showed a dose response of years of exposure in flour mills on lung function.

Adolescent↗
PubMed2003

Lung function in Pakistani welding workers.

Our objective was to study the effects of welding fumes and their duration of exposure on lung function. This was a matched case-control cross-sectional study of spirometry in 50 nonsmoking manual metal arc welders who work without the benefit of welding fume control ventilation or respiratory protective devices. Welding workers, with exposures longer than 9 years, showed a significant reduction in spirometry (forced expiratory volume in one second [FEV1], FEV1/forced vital capacity [FVC%], and peak expiratory flow [PEF]) relative to controls. Lung function in nonsmoking welding workers is impaired and stratification of results shows a dose-effect of years of welding on lung function. This effect primarily shows an obstructive pattern of airways disease. Preventive measures in developing countries have to be adopted to avert long-term lung damage in welders.

Adult↗
PubMed1994

Personnel protection during aerosol ventilation studies using radioactive technetium (Tc99m)

Two commercially available nebulizing devices used for ventilation studies were evaluated. The nebulizers use radioactive Technetium-99m (Tc99m), a potential source of room air contamination. Ambient air concentrations of Tc99m were monitored, as were the exposures of department personnel not performing ventilation studies. Room surfaces and air vents were examined to determine the extent of contamination in the examination room. Personnel were evaluated for contamination on clothing, hair, and airways when hospital lab coats and latex gloves were the only protective apparel used. Though the maximum permissible concentration of 4 x 10(-5) microCi/c3 was not exceeded, preliminary results indicated levels as high as 11,000 disintegrations/min in the nasal passages of personnel. These findings clearly demonstrate the need for more effective personal protective devices. Personnel contamination resulted primarily from the patient, due to an inability to maintain a proper oral seal on the nebulizer mouthpiece. Conventional hospital surgical masks were ineffective in reducing internal deposition to tolerable levels. By comparison, levels were reduced by 19% (p > 0.10) through use of methods such as simple body substance isolation techniques and high-efficiency disposable respirators. Levels approaching 50 disintegrations/min or less were obtainable (p < 0.001), and overall levels of Tc99m were reduced by 78%.

Aerosols↗
PubMed1996

Prevalence of self-reported respiratory disease symptoms among veterinarians in the Southern Netherlands.

In June 1991, 831 veterinarians registered in the Southern Netherlands were mailed a questionnaire to obtain details of work practice and health problems. One hundred fifty-two veterinarians were not eligible (retired or not working regularly), 497 practitioners returned a complete questionnaire (73% response rate). The purpose was to assess the prevalence of respiratory disease symptoms (RDS) and to compare the prevalence of RDS between occupational specialties and with a group of swine farmers. The professional specialty of each veterinarian was grouped as: small-animal practice (17%), large-animal practice (51%), mixed-animal practice (14%), and other practice (i.e., government, industry) (18%). Adjusted for age, gender, smoking, history of atopy, and use of respiratory protective devices, large-animal practitioners had a two times higher odds of chronic cough (OR = 1.8, 95% CI 1.1-2.8) or chronic phlegm production (OR = 2.1, 95% CI 1.1-3.7) and a three times higher odds of chest wheezing (OR = 2.8, 95% CI 1.3-6.3) than veterinarians with another specialty. Modelling the occurrence of RDS in veterinarians with exposure variables indicated that working more than 20 hr per week in swine confinement buildings increased the odds of occurrence of chronic cough and chronic phlegm production approximately three times, in addition to a significant effect of smoking. Besides a significant effect of smoking and history of atopy, no exposure variables other than occupation were associated with occurrence of asthmatic attacks in swine farmers and large-animal practitioners. Large-animal practitioners had a two times higher odds of asthmatic attacks (OR = 1.8, 95% CI 1.1-2.9) than swine farmers. Large-animal practitioners have a considerably higher proportion of symptoms like cough, phlegm production, a stuffed up nose, sneezing, and tearing eyes than small-animal practitioners during, and 4-8 hr after, working with animals.

Adult↗