Safety Goggles with Elastic Headband to Improve N95 Fit Following Failed Quantitative Fit Test.

Introduction: N95 respirators, together with eye protection, form vital elements of personal protective equipment (PPE) for healthcare workers (HCW) caring for patients with respiratory infections, such as COVID-19. Duckbill N95 respirators are widely used but have a high failure rate when Fit Tested. The commonest site for inward leaks is the region between the nose and maxilla. Safety goggles with an elastic headband may press the upper rim of the respirator against the face, thereby reducing inward leaks. We hypothesized that the use of safety goggles with an elastic headband will improve the overall fit-factor of a duckbill N95 respirator and increase the proportion of users who pass a quantitative Fit Test. Methods: About 60 volunteer HCWs, who had previously failed quantitative Fit Testing with a duckbill N95 respirator, participated in this before-and-after intervention study. A PortaCount® 8048 was used for quantitative Fit Testing. The test was first performed with a duckbill N95 respirator only. It was then repeated after participants donned a pair of safety goggles (3M Fahrenheit, ID 70071531621). Results: Before the intervention, i.e., with the respirator only, 8 (13.3%) participants passed their Fit Test. This increased to 49 (81.7%) after the application of safety goggles (OR 42, 95% CI 7.14-1697.9, p < 0.0001). The adjusted mean overall fit factor, using Tobit regression analysis, increased from 40.3 to 193.0 (t = 12.32, p < 0.001). Conclusion: The use of safety goggles with an elastic headband significantly increases the proportion of users who pass a quantitative Fit Test and improves the fit-factor of a duckbill N95 respirator. How to cite this article: Kamal M, Bhatti M, Stewart WC, Johns M, Collins D, Shehabi Y, et al. Safety Goggles with Elastic Headband to Improve N95 Fit Following Failed Quantitative Fit Test. Indian J Crit Care Med 2023;27(6):386-391.

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.

Fit Factor Change on Quantitative Fit Testing of Duckbill N95 Respirators with the Use of Safety Goggles.

N95 respirators and safety goggles are important components of personal protective equipment to reduce the spread of airborne infections, such as COVID-19, among healthcare workers. Poor N95 respirator seal may reduce its protective effect, thereby increasing transmission. Quantitative fit testing is an established way of assessing the N95 respirator fit, which provides a quantitative measure for seal, called the fit factor. Duckbill N95 respirators frequently fail the fit test. We hypothesized that using safety goggles with a wraparound elastic headband will increase their fit-factor by reinforcing the seal between the face and the upper margin of the respirator. We studied the effect of safety goggles with a wraparound elastic headband (3M™ Chemical Splash Resistant Goggles, ID 70006982741) on the fit factor of two types of Duckbill N95 respirators (Halyard FLUIDSHIELD*3, Model 99SA070M, and ProShield® N95 Model TN01-11) in 63 healthy volunteers in a nonrandomized, before-and-after intervention study design. The mean fit factor increased from 69.4 to 169.1 increased from 17/63 (27%) to 46/63 (73%) after the intervention (p <0.0001, OR 3 [95% CI = 4.9-1223]). This is the first study to explore the impact of safety goggles on N95 respirator fit. We conclude that the use of safety goggles with a wraparound elastic headband increases the fit factor of the tested Duckbill N95 respirators. HOW TO CITE THIS ARTICLE: Johns M, Kyaw S, Lim R, Stewart WC, Thambiraj SR, Shehabi Y, et al. Fit Factor Change on Quantitative Fit Testing of Duckbill N95 Respirators with the Use of Safety Goggles. Indian J Crit Care Med 2021;25(9):981-986.

Autonomic, behavioral, and neural analyses of mild conditioned negative affect in marmosets.

Avoidance and alerting behaviors and accompanying physiological responses, including changes in heart rate (HR), are core components of negative emotion. Investigations into the neural mechanisms underlying the regulation and integration of these responses require animal models that simultaneously measure both the physiological and behavioral components of emotion. A primate model is of particular importance in view of the well developed prefrontal cortex of primates, and this region's critical role in emotion regulation and the etiology of affective disorders. Therefore, we have developed a simple aversive conditioning paradigm to assess, simultaneously, cardiovascular and behavioral responses in the marmoset (Callithrix jacchus). Validation of the paradigm was achieved by (1) comparing conditioned responses to a predictive cue with pseudoconditioned responses to a nonpredictive cue; (2) assessing the acquisition of conditioning following lesions of the amygdala, a region essential for associative learning in humans and rats; and (3) determining the contributions of the sympathetic and parasympathetic nervous system to the conditioned autonomic responses. Marmosets acquired conditioned HR and behavioral responses in the conditioned, but not the pseudoconditioned or amygdala lesioned groups. Conditioned HR accelerations were reduced by both parasympathetic and sympathetic blockade. Thus, a model of associative learning of mild negative emotion in the marmoset has been validated by psychological, neurological, and pharmacological investigation. Future studies will determine the role of the prefrontal cortex in the regulation of these negative emotional responses, to provide insights into the neuropathology of affective disorders.