Breathability and Safety Testing of Personal Protective Equipment: "Human-comfort" Factor Remains Undefined

Prussian Blue Sensor for Bacteria Detection in Personal Protection Clothing

Biological hazards can be defined as substances that endanger the life of any living organism, most notably humans, and are often referred to as biohazards. Along with the use of personal protective equipment (PPE), early detection of contact is essential for the correct management and resolution of a biological threat, as well as lower mortality rates of those exposed. Herein, Prussian blue (PB) was evaluated as a functional compound applied on polyester knits to act as an on-site sensor for bacteria detection. In order to study the best compound concentration for the intended application, polymeric solutions of 0.5, 1 and 2 g/L were developed. The three conditions tested displayed high abrasion resistance (>2000 cycles). The bacterial sensing capacity of the coated knits was assessed in liquid and solid medium, with the functionalised substrates exhibiting the capability of detecting both Gram-positive and Gram-negative bacteria and changing colours from blue to white. Evaluation of water repellence and chemical penetration resistance and repellence was also performed in polyester functionalised with PB 0.5 and 1 g/L. Both knits showed a hydrophobic behaviour and a capacity to resist to penetration of chemicals and level 3 repellence effect for both acid and base chemicals.

Prediction of N95 Respirator Fit from Fogging of Eyeglasses: A Pilot Study

Aim and objective

Fogging of eyeglasses while wearing N95 respirators is common. It is commonly held that the N95 respirator has a poor fit if there is fogging of eyeglasses. We conducted this prospective, pilot study to determine if fogging of eyeglasses predicts poor fit of N95 respirator.

Materials and methods

Seventy volunteer healthcare workers from a tertiary intensive care unit in Sydney, Australia participated. The participants donned one of the following N95 respirators: three-panel flat-fold respirator (3M 1870), cup-shaped respirator (3M 1860), or a duckbill respirator. After a satisfactory "user seal check" as recommended by the manufacturer, the participants donned eyeglasses and checked for fogging. A quantitative fit test (QnFT) of the respirator was then performed (using PortaCount Respirator Fit Tester 8048, TSI Inc., Minnesota, USA). A fit factor of <100 on quantitative fit testing indicates poor fit. The sensitivity and specificity for fogging of eyeglasses (index test) to predict the poor fit of N95 respirator was determined, compared to QnFT (gold standard test).

Results

Fogging of eyeglasses as a predictor of poor respirator fit (i.e., fit factor <100 on QnFT) had sensitivity of 71% (95% CI, 54-85%) and specificity 46% (95% CI, 29-63%). The odds ratio of fogging as a predictor for poor fit was 2.10 (95% CI, 0.78-5.67), with a two-tailed p-value of 0.22 (not significant). The receiver operating characteristic curve for fogging of eyeglasses as a diagnostic test had the area under the curve of 0.59.

Conclusion

Fogging of eyeglasses is neither a sensitive nor a specific predictor for poor fit of N95 respirators.

How to cite this article

Kyaw S, Johns M, Lim R, Stewart WC, Rojas N, Thambiraj SR, et al. Prediction of N95 Respirator Fit from Fogging of Eyeglasses: A Pilot Study. Indian J Crit Care Med 2021;25(9):976-980.

Key ingredients and recycling strategy of personal protective equipment (PPE): Towards sustainable solution for the COVID-19 like pandemics

The COVID-19 pandemic has intensified the complications of plastic trash management and disposal. The current situation of living in fear of transmission of the COVID-19 virus has further transformed our behavioural models, such as regularly using personal protective equipment (PPE) kits and single-use applications for day to day needs etc. It has been estimated that with the passage of the coronavirus epidemic every month, there is expected use of 200 billion pieces of single-use facemasks and gloves. PPE are well established now as life-saving items for medicinal specialists to stay safe through the COVID-19 pandemic. Different processes such as glycolysis, hydrogenation, aminolysis, hydrolysis, pyrolysis, and gasification are now working on finding advanced technologies to transfer waste PPE into value-added products. Here, in this article, we have discussed the recycling strategies of PPE, important components (such as medical gloves, gowns, masks & respirators and other face and eye protection) and the raw materials used in PPE kits. Further, the value addition methods to recycling the PPE kits, chemical & apparatus used in recycling and recycling components into value-added products. Finally, the biorenewable materials in PPE for textiles components have been discussed along with concluded remarks.