Evaluation of Surgical N95 Respirators Covered With Combinations of Masks and Face Shield.

Objective: The aim of the study is to evaluate the metabolic demands and internal breathing environments when covering an N95 with a surgical mask, cloth mask, and/or FS.

Methods: Three N95 models approved by the National Institute for Occupational Safety and Health were evaluated under six covering conditions using the National Institute for Occupational Safety and Health Automated Breathing and Metabolic Simulator. All conditions used one trial with each N95 for six incremental 5-minute work rates.

Effects of 5-Day Heat Acclimation on Workers Wearing Personal Protective Clothing.

Introduction: Elevated ambient temperature and personal protective clothing (PPC) induce physiological strain which may be counteracted by heat acclimation. The purpose of this study was to determine if 5-day heat acclimation training (HAT) improves thermal and perceptual responses while wearing chemical, biological, radiological, and nuclear (CBRN) PPC.

Methods: Nine healthy men completed a heat stress test (walking for one hour with CBRN PPC) in 35°C and 50% relative humidity (RH) before and after 5-day HAT.

Powered air-purifying respirator use in healthcare: Effects on thermal sensations and comfort.

Twelve subjects wore an N95 filtering facepiece respirator (N95 FFR), one tight-fitting full facepiece powered air-purifying respirator (PAPR), two loose-fitting PAPRs, and one elastomeric/PAPR hybrid for 1 hr each during treadmill walking at 5.6 km/hr while undergoing physiological and subjective response monitoring. No significant interaction (p ≥ .

Project BREATHE - Prototype Respirator Evaluation Utilizing Newly Proposed Respirator Test Criteria.

Machine and human subject testing of four prototype filtering facepiece respirators (FFR) and two commercial FFR was carried out utilizing recently proposed respirator test criteria that address healthcare worker-identified comfort and tolerance issues. Overall, two FFR (one prototype, one commercial model) were able to pass all eight criteria and three FFR (two prototypes, one commercial model) were able to pass seven of eight criteria. One prototype FFR was not tested against the criteria due to an inability to obtain satisfactory results on human subject quantitative respirator fit testing.

Umbilical temperature correlation with core and skin temperatures at rest, in the heat and during physical activity.

Purpose: to determine the correlation of umbilical temperatures (T) with simultaneously recorded chest wall temperature (T) and rectal temperature (T) in adults during rest, heat exposure and exercise.

Methods: A total of 28 healthy men, wearing different types of clothing (athletic garb, a spandex full body heating garment, firefighter bunker gear) had average and peak umbilical, chest wall and rectal temperature measurements taken during sedentary temperature stabilisation stages, heat exposure periods and active exercise phases.

Results: Curvilinear relationships were noted between T and T compared with T and their association became noticeably positive and linear at approximately 35.

Comparison of estimated core body temperature measured with the BioHarness and rectal temperature under several heat stress conditions.

Monitoring and measuring core body temperature is important to prevent or minimize physiological strain and cognitive dysfunction for workers such as first responders (e.g., firefighters) and military personnel.

Physiologic Effects from Using Tight- and Loose-Fitting Powered Air-Purifying Respirators on Inhaled Gases, Peak Pressures, and Inhalation Temperatures During Rest and Exercise.

The goal of this investigation was to evaluate the physiologic stresses of powered air-purifying respirators (PAPRs) used by workers in many industries (e.g., health care, automobile repair, public safety, building trades, etc.

Physiologic and fit factor profiles of N95 and P100 filtering facepiece respirators for use in hot, humid environments.

Background: To determine if hot, humid ambient conditions impact filtering facepiece respirators' (FFRs') fit, and to evaluate differences in physiologic and subjective responses between N95 FFRs and P100 FFRs.

Methods: Twelve subjects had physiologic monitoring and subjective perceptions monitored over 1 hour of treadmill exercise (5.6 km/h) in an environmental chamber (35°C, relative humidity 50%) wearing an N95 FFR, P100 FFR, or no respirator.

Pressure drop of filtering facepiece respirators: How low should we go?

Introduction: This study was undertaken to determine the mean peak filter resistance to airflow (Rfilter) encountered by subjects while wearing prototype filtering facepiece respirators (PRs) with low Rfilter during nasal and oral breathing at sedentary and low-moderate work rates.

Material And Methods: In-line pressure transducer measurements of mean Rfilteracross PRs with nominal Rfilter of 29.4 Pa, 58.

Effect of Pregnancy Upon Facial Anthropometrics and Respirator Fit Testing.

Workers required to wear respirators must undergo additional respirator fit testing if a significant change in body weight occurs. Approximately 10% of working women of reproductive age will be pregnant and experience a significant change in weight, yet the effect of pregnancy-associated weight gain on respirator fit is unknown. Cephalo-facial anthropometric measurements and quantitative fit testing of N95 filtering facepiece respirators (N95 FFR) of 15 pregnant women and 15 matched, non-pregnant women were undertaken for comparisons between the groups.

Effect of external airflow resistive load on postural and exercise-associated cardiovascular and pulmonary responses in pregnancy: a case control study.

Background: Facial coverings (e.g., balaclavas, niqabs, medical/surgical masks, respirators, etc.

Effect of wearing an N95 respirator on infrared tympanic membrane temperature measurements.

To determine the impact of wearing an N95 filtering facepiece respirator (N95 FFR) on tympanic temperature measurements. TMT measurements, with and without wearing an N95 filtering facepiece respirator (N95 FFR) were obtained at the onset and termination of 1 h of treadmill exercise in 21 subjects, and at staggered time intervals (0, 20, 40, 60 min) during combined sedentary activity and exercise of another 46 subjects, to determine any effect on TMT. A total of 877 TMT measurements were obtained that demonstrated a mean TMT increase of 0.

Effect of short-term heat acclimation training on kinetics of lactate removal following maximal exercise.

Background: Heat acclimation (HA) evokes numerous physiological adaptations, improves heat tolerance and has also been shown to enhance lactate (LA) responses during exercise, similar to that seen with endurance training. The purpose of this study was to examine whether HA improves the body's ability to remove LA during recovery following maximal exercise.

Methods: Ten healthy men completed two trials of maximal treadmill exercise (pre- and post-HA) separated by 5 days of HA.

N95 respirator use during advanced pregnancy.

Background: To determine the physiological and subjective effects of wearing an N95 filtering facepiece respirator (N95 FFR) in advanced stages of pregnancy.

Methods: Healthy pregnant women (n = 22) and nonpregnant women (n = 22) had physiological and subjective measurements taken with and without wearing an N95 FFR during exercise and postural sedentary activities over a 1-hour period.

Results: There were no differences between the pregnant and nonpregnant women with respect to heart rate, respiratory rate, oxygen saturation, transcutaneous carbon dioxide level, chest wall temperature, aural temperature, and subjective perceptions of exertion and thermal comfort.

Impact of low filter resistances on subjective and physiological responses to filtering facepiece respirators.

Ten subjects underwent treadmill exercise at 5.6 km/h over one hour while wearing each of three identical appearing, cup-shaped, prototype filtering facepiece respirators that differed only in their filter resistances (3 mm, 6 mm, and 9 mm H2O pressure drop). There were no statistically significant differences between filtering facepiece respirators with respect to impact on physiological parameters (i.

A Review of Mine Rescue Ensembles for Underground Coal Mining in the United States.

The mining industry is among the top ten industries nationwide with high occupational injury and fatality rates, and mine rescue response may be considered one of the most hazardous activities in mining operations. In the aftermath of an underground mine fire, explosion or water inundation, specially equipped and trained teams have been sent underground to fight fires, rescue entrapped miners, test atmospheric conditions, investigate the causes of the disaster, or recover the dead. Special personal protective ensembles are used by the team members to improve the protection of rescuers against the hazards of mine rescue and recovery.

Physiological evaluation of air-fed ensembles.

The goal of this study was to evaluate the respiratory and metabolic stresses of air-fed ensembles used by workers in the nuclear, chemical, and pharmaceutical industries during rest, low-, and moderate-intensity treadmill exercise. Fourteen men and six women wore two different air-fed ensembles (AFE-1 and AFE-2) and one two-piece supplied-air respirator (SA) at rest (REST) and while walking for 6min at oxygen consumption (V.O2) rates of 1.

Evaluation of N95 respirator use with a surgical mask cover: effects on breathing resistance and inhaled carbon dioxide.

Objective: For pandemic influenza outbreaks, the Institute of Medicine has recommended using a surgical mask cover (SM) over N95 filtering facepiece respirators (FFRs) among healthcare workers as one strategy to avoid surface contamination of the FFR which would extend its efficacy and reduce the threat of exhausting FFR supplies. The objective of this investigation was to measure breathing air quality and breathing resistance when using FFRs with US Food and Drug Administration-cleared SM and without SM.

Methods: Thirty National Institute for Occupational Safety and Health (NIOSH)-approved FFR models with and without SM were evaluated using the NIOSH Automated Breathing and Metabolic Simulator (ABMS) through six incremental work rates.

Impact of multiple consecutive donnings on filtering facepiece respirator fit.

Background: A concern with reuse of National Institute for Occupational Safety and Health-certified N95 filtering facepiece respirators (FFRs) is that multiple donnings could stress FFR components, impairing fit. This study investigated the impact of multiple donnings on the facepiece fit of 6 N95 FFR models using a group of 10 experienced test subjects per model.

Methods: The TSI PORTACOUNT Plus and N95 Companion accessory were used for all tests.

Effect of exhaled moisture on breathing resistance of N95 filtering facepiece respirators.

This study evaluated the effect of exhaled moisture on the breathing resistance of three classes of filtering facepiece respirators (FFR) following 4 h of continuous wear at a breathing volume of 40 l min(-1), utilizing an automated breathing and metabolic simulator as a human surrogate. After 4 h, inhalation and exhalation resistance increased by 0.43 and 0.

Physiological impact of the N95 filtering facepiece respirator on healthcare workers.

Objective: To assess the physiological impact of the N95 filtering facepiece respirator (FFR) on healthcare workers.

Methods: Ten healthcare workers each conducted multiple 1-hour treadmill walking sessions, at 1.7 miles/h, and at 2.

Surgical mask placement over N95 filtering facepiece respirators: physiological effects on healthcare workers.

Background And Objective: Filtering facepiece respirators ('N95 Masks') may be in short supply during large-scale infectious outbreaks. Suggestions have been made to extend their useful life by using a surgical mask as an outer barrier, but the physiological impact of this added barrier upon the wearer has not been studied.

Methods: A surgical mask was worn over an N95 filtering facepiece respirator by 10 healthcare workers for 1 h at each of two work rates.

Reusable elastomeric air-purifying respirators: physiologic impact on health care workers.

Background: Elastomeric air-purifying respirators offer the benefit of reusability, but their physiological impact on health care workers is unknown.

Methods: Ten health care workers exercised at 2 health care-associated work rates wearing an elastomeric air-purifying respirator. Mixed inhalation/exhalation respirator dead space gases (oxygen, carbon dioxide) were sampled, and physiological parameters were monitored (heart rate, breathing rate, tidal volume, minute volume, oxygen saturation, transcutaneous carbon dioxide).

Effects of fire fighter protective ensembles on mobility and performance.

Many studies have shown that fire fighter turnout gear and equipment may restrict mobility. The restriction of movement is usually due to a decrease in range of motion (ROM). It is important to know how much the decrease in ROM affects performance.

Physiological monitoring in firefighter ensembles: wearable plethysmographic sensor vest versus standard equipment.

We evaluated the accuracy of a wearable sensor vest for real-time monitoring of physiological responses to treadmill exercise. Ten subjects in standard firefighter ensembles, treadmill exercising at 50% VO(2) max, had heart rate (HR), respiratory rate (RR), skin temperature (T(sk)), oxygen saturation (SaO(2)), tidal volume (V(T)), and minute ventilation (V(E)) recorded concurrently by a wearable plethysmographic sensor vest and standard laboratory physiological monitoring equipment for comparison. A high degree of correlation was noted for most of the measured variables [HR (r = 0.