Investigation of the barrier performance of disposable isolation gowns

BACKGROUND

Recent epidemics and pandemics highlighted the need for effective personal protective equipment, including isolation gowns. The most critical property of an isolation gown is its ability to keep liquids and viruses from passing through the gown. Liquid and viral barrier penetration can be measured using laboratory test methods. Association for the Advancement of Medical Instrumentation (AAMI) PB70 standard defines isolation gown barrier performance levels and requirements. In this study, 22 disposable isolation gown models from 6 manufacturers were tested for liquid and viral penetration resistance.

METHODS

Standard test methods were used to evaluate water and viral penetration. Test results were evaluated using AAMI PB70 barrier performance criteria for 4 protection levels.

RESULTS

Seven of the 22 tested gown models did not pass liquid and viral penetration testing based on AAMI PB70 at the level claimed by the manufacturer. The majority of these failures occurred at the seam and/or tie attachment areas.

CONCLUSIONS

The study findings underscore the need for improved processes surrounding activities such as premarket testing and postmarket evaluation of gowns according to standardized test methods by third-party laboratories. This study also supports the recent Food and Drug Administration guidance document that clarified the characteristics of isolation gowns considered to be class II and subject to Food and Drug Administration premarket review. Infection preventionists, hospital purchasers, and safety professionals should seek isolation gowns demonstrating conformance to industry standards from manufacturers.

Impact of surface tension on the barrier performance of gowns and coveralls

BACKGROUND

Health care workers and laboratory workers who are routinely exposed to potentially life-threatening infectious diseases should wear protective clothing when anticipating contact with infectious materials. The most critical property of protective clothing is its ability to prevent liquids and viruses from passing through the garment. There are a number of potentially infectious liquids that workers may be exposed to during routine tasks. Each liquid has different physical and chemical properties that affect penetration. However, the current test methods use a limited number of liquids for classifying the barrier performance. The impact of the surface tension of the challenge liquid on the penetration resistance of gowns and coveralls was investigated in this study.

METHODS

Eight isolation gowns and 2 coveralls were tested in accordance with American Association of Textile Chemists and Colorists 42 and American Association of Textile Chemists and Colorists 127 test methods, which were modified to incorporate the substitute challenge liquids.

RESULTS

Although current standard test methods only use water to categorize the liquid penetration resistance of minimal to moderate barrier performance gowns, a significant difference in the penetration was found when simulated body fluids were used.

CONCLUSIONS

The results suggest that safety professionals and wearers should consider the varying barrier performance of personal protective equipment with different liquids and the use limitations when selecting them for the required tasks. Furthermore, standard development organizations should consider multiple challenge liquids when classifying protective clothing for health care settings.

Evaluation of fluid leakage at the coverall and glove interface in single and double glove conditions

BACKGROUND

Fluid leakage through the glove-protective clothing interface is an area of concern for many health care personnel, including emergency medical service providers, who may wear coveralls to protect themselves from multiple types of hazards. There is currently no established standard test method to specifically evaluate the barrier performance of the glove-protective clothing interface region for any personal protective equipment ensemble.

OBJECTIVE

This study quantifies the fluid leakage at the coverall and glove interface using single and double gloving.

METHODS

A robotic arm, which can simulate upper extremity movements of health care personnel, was used to test 5 coverall models and an extended examination glove model in single and double glove conditions.

RESULTS

The results show that there was a significant difference in fluid leakage amounts between some of the coverall models and the number of glove layers studied. Findings also highlight that there is a high correlation between basis weight and stiffness of the coverall fabrics and the fluid leakage amounts.

CONCLUSIONS

These results underline that coverall constructed from thin and less stiff fabrics can result in lower fluid leakage levels. Also, there was no significant difference in fluid leakage amounts between single and double gloves when tested with each of the coverall models, with the exception of the coveralls with the highest basis weight and stiffness.

Evaluation of the Physical Performance of Disposable Isolation Gowns

BACKGROUND

The threat of emerging infectious diseases has highlighted the need for effective gowns to protect healthcare workers and patients. Although studies identified end user issues with the physical performance of gowns, the literature that evaluates the performance is scarce. This paper represents one of the first efforts to investigate the physical performance of a substantial set of isolation gown models in the marketplace.

OBJECTIVE

Physical performance of 20 commercial and two experimental disposable isolation gowns was evaluated.

METHODS

Standard test methods were used to investigate a range of properties including; thickness, weight, tensile strength, tearing strength, and seam strength.

RESULTS

In general, due to the differences in the fibers and methods used for the construction, large variations in the tensile, tear, and seam strength results were found. When the gowns were compared to their respective AAMI PB70 protection levels, no clear trend was found between protection levels and tear strength or between protection levels and seam strength, while there was a linear relationship between gowns' AAMI PB70 levels and their tensile strength. It was found that fabric construction significantly affects the physical performance of gowns.

CONCLUSIONS

Based on this work, a new standard, ASTM F3352, was published and has been recognized by the FDA. ASTM F3352 is expected to help end users in selecting the appropriate protective clothing.

A simulation study to assess fluid leakage through the glove-gown interface in isolation settings

BACKGROUND

Isolation gowns are recommended to protect healthcare personnel, patients, and visitors from transfer of microorganisms and body fluids in patient isolation situations. Standards provide limited information about barrier performance of isolation gowns for possible exposure scenarios. One of the most vulnerable areas of the personal protective equipment ensemble is considered the glove-gown interface. However, current isolation gown classification standards do not consider the interface regions of the personal protective equipment system while assessing the level of protection. The purpose of this study was to quantitatively evaluate the fluid leakage through the glove-gown interface by simulating exposures and healthcare personnel arm movements in patient care for isolation settings.

METHODS

We tested fluid leakage of two examination gloves with different cuff lengths and seven isolation gown models designed with varying levels of barrier resistance and multiple cuff types.

RESULTS

Our results demonstrated that leakage through the glove-gown interface depends on multiple factors, including glove cuff length and gown cuff design. Gowns with the thumb loop design provided better protection than the elastic cuff design, and the elastic cuff design provided better protection compared to the knit cuff design for a given AAMI PB70 level. More importantly, a substantial penetration through gown fabrics was observed.

CONCLUSIONS

This research identifies a need to develop a standardized method to evaluate leakage at the glove-gown interface to improve worker protection.

Barrier resistance of double layer isolation gowns

Background

Isolation gowns are one of the crucial pieces of personal protective equipment (PPE) to prevent the migration of microorganisms and body fluids from patients to health care personnel and vice versa. Underperforming isolation gowns in terms of fluid resistance, could potentially put lives in danger. Wearing multiple layers of isolation gowns could theoretically increase the fluid penetration resistance. This study investigates if 2-layer lower barrier level isolation gowns meet the barrier effectiveness requirements of a single higher barrier level isolation gown.

Methods

Three commonly used ANSI/AAMI Level 2 isolation gown models were selected and tested in single layer and double layer configurations in accordance with ANSI/AAMI PB70 requirements.

Results

Total of 240 experiments were conducted to analyze the effects of gown model, fabric region, and the number of gown layers on AATCC 127 and AATCC 42 test results. In regard to AATCC 42, there was a significant difference among the different gown models, and the number of gown layers. Similar to AATCC 42 results, there was a significant difference among the different gown models, and the number of gown layers for AATCC 127; additionally, the gown regions was also significantly different.

Conclusion

Test results demonstrated that the double layer isolation gown configurations do not always provide equal fluid penetration resistance as required for a single Level 3 isolation gown using the standard test methods specified in ANSI/AAMI PB70.

Household Materials Selection for Homemade Cloth Face Coverings and Their Filtration Efficiency Enhancement with Triboelectric Charging

The COVID-19 pandemic is currently causing a severe disruption and shortage in the global supply chain of necessary personal protective equipment (e.g., N95 respirators). The U.S. CDC has recommended use of household cloth by the general public to make cloth face coverings as a method of source control. We evaluated the filtration properties of natural and synthetic materials using a modified procedure for N95 respirator approval. Common fabrics of cotton, polyester, nylon, and silk had filtration efficiency of 5-25%, polypropylene spunbond had filtration efficiency 6-10%, and paper-based products had filtration efficiency of 10-20%. An advantage of polypropylene spunbond is that it can be simply triboelectrically charged to enhance the filtration efficiency (from 6 to >10%) without any increase in pressure (stable overnight and in humid environments). Using the filtration quality factor, fabric microstructure, and charging ability, we are able to provide an assessment of suggested fabric materials for homemade facial coverings.

Planning for Epidemics and Pandemics: Assessing the Potential Impact of Extended Use and Reuse Strategies on Respirator Usage Rates to Support Supply-and-Demand Planning Efforts

During epidemics and pandemics healthcare personnel (HCP) are on the front line of disease containment and mitigation. Personal protective equipment (PPE), such as NIOSH-approved N95 filtering facepiece respirators (FFRs), serve an important role in minimizing HCP risks and are in high demand during public health emergencies. Because PPE demand can exceed supply, various public health strategies have been developed to reduce the rate of PPE consumption as supply dwindles. Extended use and limited reuse of N95 FFRs are strategies advocated by many governmental agencies used to increase the number of times a device can be used. Increased use of respirators designed for reuse-such as powered air-purifying respirators (PAPRs) and elastomeric half-mask and full facepiece air-purifying respirators- is another option designed to reduce the continuous need for new devices as the daily need for respirator use increases. Together, these strategies are designed to reduce the number of PPE units that must be discarded daily and, therefore, extend the longevity of available supply. The purpose of this paper is to theoretically estimate the impact of extended use and limited reuse strategies for N95 FFRs and the increased use of reusable respirator options on PPE consumed. The results suggest that a considerable reduction in PPE consumption would result from extended use and limited reuse of N95 FFRs and the increased use of respirators designed for reuse; however, the practical benefits must be balanced with the risks and economic costs. In addition, extended use and reuse strategies must be accompanied by proper procedures to reduce risk. The study is designed to support epidemic and pandemic PPE supply and demand planning efforts.

Critical investigation of glove-gown interface barrier performance in simulated surgical settings

The barrier properties of personal protective equipment are vital to healthcare personnel to protect themselves from possible infectious body fluids. Intraoperative exposure of healthcare personnel to body fluids can be substantial in both inpatient and outpatient settings. The glove-gown interface is known as one of the weakest points of the whole personal protective equipment system. However, there is a lack of scientific research designed to investigate the problem. This paper reports the results of experiments using a new testing methodology developed to quantify fluid leakage through the glove-gown interface while simulating surgical settings in terms of operating room personnel activities, exposure types, exposure durations, and physical stresses applied on the interface. This study represents one of the first efforts investigating the amount of fluid leakage through the glove-gown interface for a number of surgical gown and glove models while considering glove material differences and single vs. double gloving. The test results showed that there is a significant difference in fluid leakage amounts between three gown models and four glove models studied. The results also demonstrated that double gloving significantly reduced the fluid leakage compared to single glove use. The mean fluid leakage was lower in the double synthetic glove configurations (M = 2.76g) compared with all other configurations (3GLV, M = 8.3g; 4GLV, M = 9.49g; 5GLV, M = 3.08g; 6GLV, M = 20.03g; double latex, M = 5.22g). Findings highlighted a significant interaction between glove and gown designs, which suggests that gown and gloves should be designed together as a system to minimize or eliminate the fluid leakage.

Novel Test Method for the Evaluation of Fluid Leakage at the Glove-Gown Interface and Investigation of Test Parameters

BACKGROUND

Exposure to patients' blood/body fluids could be life-affecting, when providing care to patients with infectious diseases. Although the glove-gown interface is considered one of the weakest points of the protective ensemble system, there is a lack of research, and existing standards do not provide much guidance on strategies to minimize gaps between the gowns and gloves. Currently, there is no known standard test method to evaluate fluid leakage or assess performance improvements with new gowns/gloves.

STUDY DESIGN

A novel test method with a robotic arm, which has the capability to simulate health care personnel's arm movements during fluid exposure, was developed to determine the leakage at the glove-gown interface. This article explains the test method and investigates the effect of movement, exposure type, exposure duration, procedure duration, and existence of pressure on the amount of leaked fluid at the glove-gown interface.

RESULTS

Test results suggest that, with the exception of procedure duration, all parameters significantly affected the amount of fluid leaked at the glove-gown interface. Leakage was higher for soaking when compared to spraying, increased as the exposure duration increased, and was greater with the application of pressure.

CONCLUSIONS

The novel method developed in this study could be used by manufacturers of personal protective equipment to evaluate their products. Standard development organizations could adapt this test method in their specifications, testing standards, and guidelines.