We want to thank Martin Kauke, MD, for his invaluable contribution to this project. There was no financial compensation for this contribution.
ObjectiveThe COVID-19 pandemic has precipitated widespread shortages of filtering facepiece respirators (FFRs) and the creation and sharing of proposed substitutes (novel designs, repurposed materials) with limited testing against regulatory standards. We aimed to categorically test the efficacy and fit of potential N95 respirator substitutes using protocols that can be replicated in university laboratories.SettingAcademic medical centre with occupational health-supervised fit testing along with laboratory studies.ParticipantsSeven adult volunteers who passed quantitative fit testing for small-sized (n=2) and regular-sized (n=5) commercial N95 respirators.MethodsFive open-source potential N95 respirator substitutes were evaluated and compared with commercial National Institute for Occupational Safety and Health (NIOSH)-approved N95 respirators as controls. Fit testing using the 7-minute standardised Occupational Safety and Health Administration fit test was performed. In addition, protocols that can be performed in university laboratories for materials testing (filtration efficiency, air resistance and fluid resistance) were developed to evaluate alternate filtration materials.ResultsAmong five open-source, improvised substitutes evaluated in this study, only one (which included a commercial elastomeric mask and commercial HEPA filter) passed a standard quantitative fit test. The four alternative materials evaluated for filtration efficiency (67%–89%) failed to meet the 95% threshold at a face velocity (7.6 cm/s) equivalent to that of a NIOSH particle filtration test for the control N95 FFR. In addition, for all but one material, the small surface area of two 3D-printed substitutes resulted in air resistance that was above the maximum in the NIOSH standard.ConclusionsTesting protocols such as those described here are essential to evaluate proposed improvised respiratory protection substitutes, and our testing platform could be replicated by teams with similar cross-disciplinary research capacity. Healthcare professionals should be cautious of claims associated with improvised respirators when suggested as FFR substitutes.
Objectives/Hypothesis Injection laryngoplasty has become valuable in treating laryngologic disorders including vocal cord atrophy, paralysis, and paresis. Although materials such as carboxymethylcellulose and calcium hydroxylapatite are Food and Drug Administration (FDA) approved, they are not without limitations. Juvederm (hyaluronic acid) is an alternative treatment that is not FDA approved. Although studies have examined Juvederm's longevity in cutaneous injections, there are limited data examining durability of Juvederm used in laryngoplasty. We aimed to determine the longevity and effectiveness of Juvederm used in injection laryngoplasty. Study Design Retrospective cohort study. Methods Subjects who underwent injection laryngoplasty using Juvederm were reviewed. Longevity was defined as the time between injection and the date that a patient first noted subjective deterioration of their voice. All subjects were subsequently followed using videostroboscopy to evaluate for Juvederm resorption. Longevity was analyzed using a Kaplan‐Meier survival model, and effectiveness of laryngoplasty was determined using the Voice‐Related Quality of Life index scores and analyzed using a Wilcoxon signed ranks test. Results Fifty‐nine subjects met inclusion criteria and underwent Juvederm injection laryngoplasty. Kaplan‐Meier survival analysis revealed a mean longevity of 10.6 months (95% confidence interval: 9.1‐12.0 months). Wilcoxon signed ranks analysis of the pre‐ and postinjection Voice Related Quality of Life (VRQOL) scores revealed improvement, with a mean preinjection VRQOL of 49.2 (standard deviation [SD] = 25.8) and mean postinjection VRQOL of 68.2 (SD = 27.5) (P < .001). Conclusions Injection laryngoplasty using Juvederm is an effective treatment for vocal cord atrophy, paralysis, and paresis. Knowledge of the patient‐defined duration of benefit following laryngoplasty using Juvederm plays an important role in counseling patients as well as in the planning of future interventions. Level of Evidence 4 Laryngoscope, 129:2744–2747, 2019
Novel designs and materials for filtering face-piece respirators (FFRs) have been disseminated in response to shortages during the COVID-19 pandemic. Since filtration efficiency depends on particle diameter and air face velocity, the relevance of material filtration or prototype fit data depends on test conditions. We investigate whether characterizing a material in a filter holder at a range of face velocities enabled precise prediction of the filtration performance of a novel sewn mask design. While larger particles (> 500 nm) are more relevant for inhalation exposure to respiratory emissions, we compare this mask and a N95 FFR (as a control) with smaller particles more similar to those in the N95 test method. Sewn from sterilization wrap, our mask (sealed to a mannequin head with silicone) filters 85 ± 1% of 136 nm particles (NaCl, 85 L min -1 ) and passes quantitative fit tests for 4 of 6 volunteers, representing intermediate protection between a surgical mask and N95 FFR. Filter holder material measurements overpredict the sewn mask's filtration efficiency by 8.2% (95% CI 7.4-9.1%) (136 or 200 nm). While testing flat material in a filter holder enables comparison between materials, filtration performance does not precisely scale-up from filter holder to mannequin tests. Testing full prototypes at relevant conditions is crucial if an improvised design is intended as a substitute for a commercial surgical mask or FFR.
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