Which alternative well-fit masks can be used in medical procedures?

BACKGROUND: During the COVID-19 pandemic, the WHO and CDC recommended that healthcare personnel (HCPs) performing non-aerosol-generating procedures (AGPs) don a properly fitted mask. We aimed to evaluate the fit factors (FFs) of eight alternative well-fit masks (AWMs) used by Thai HCPs. METHODS: This comparative descriptive study was conducted on 33 HCPs between October and November 2022, categorized into three facial sizes: small, medium, and large. Each participant wore eight types of AWMs in random order: medical mask under adjustable ear-loop (AEL)-KF94 (MK), medical mask under AEL-KN95 with a hook (MN), medical mask under fabric mask (MF), AEL- KF94 (KF94), AEL-KF94 under fabric masks (KF), AEL-KF94 with a hook (KF94H), AEL-KN95 with a hook (KN95), and AEL-KN95 with a hook under fabric mask (NF). FFs were measured using a quantitative fit test. RESULTS: The respective number of HCPs wearing small, medium, and large was 12, 12, and 9, and the mean±SD of face width and length was 132.98 ± 10.49 and 114.92 ± 10.10 mm. The highest respective median of FF was KN95 = 200, NF= 200, MN= 185, and KF94H = 171, and the respective passing fit-test rate was 97%, 84.8%, 63.6%, and 60.6%. There was no difference in FFs between the N95 and KN95 (p=0.72), the N95 and NF (p=0.202), and the three face sizes. Moreover, KF94H pass rates were significantly higher for females compared to males (OR = 13.3; p = 0.001) and for small facial sizes compared to either medium or large sizes (OR = 14.7; p = 0.009). CONCLUSION: The AEL-KN95 with hook and sponge at the nosepiece is an effective respirator for use by HCPs in non-AGPs, as the FF and fit test pass rates were comparable to those of N95, and there were no differences in FFs between facial sizes. However, the female who had a small face size may use a KF94H as an alternative PPE.

Development and Validation of a Discriminative Dissolution Medium for a Poorly Soluble Nutraceutical Tetrahydrocurcumin

Objectives: The present study aimed to develop and validate a discriminative dissolution method for tetrahydrocurcumin (THC), a Biopharmaceutical Classification System class II drug, by a simple ultraviolet (UV) spectrophotometric analysis. The final dissolution medium composition was selected based on the solubility and stability criteria of the drug. Materials and Methods: As a prerequisite for this, the solubility of the drug was assessed in media of different pH (1.2-7.4), and surfactant concentrations of 0.5-1.5% (w/v) sodium lauryl sulfate (SLS) in water, and pH 7.4 phosphate buffer. The dissolved drug concentration in each medium was quantified by UV analysis at 280 nm wavelength. Results: The drug solubility was found to be high at a pH of 1.2 and 7.4. The media with surfactant enhanced solubility of the drug by approximately 17-fold and exhibited better sink conditions. The discriminative power of the developed dissolution medium (i.e., 1% w/v SLS in pH 7.4) was determined by performing in vitro dissolution studies of the prepared THC tablets and comparing their release profiles using fit factors (f1 and f2). The results of the fit factor comparisons made between the dissolution profiles of THC tablets proved the discriminative ability of the medium. The validation of the developed dissolution method was performed by international guidelines and the method showed specificity, linearity, accuracy, and precision within the acceptable range. Conclusion: The proposed dissolution method was found to be adequate for the routine quality control analysis of THC, as there is no specified dissolution method for the drug in the pharmacopoeia.

Evaluation of CBRN Respirator Protection in Simulated Fire Overhaul Settings.

Overhaul is the phase of firefighting after flames have been extinguished but when products of combustion are still being released. While positive pressure self-contained breathing apparatus (SCBA) provide the highest level of respiratory protection during overhaul, use of air-purifying respirators (APRs) with suitable filters could potentially provide a lower weight, longer duration option for first responders. The objective of this study was to assess whether an APR with a chemical, biological, radiological, and nuclear (CBRN) canister could be recommended as substitution for SCBA during overhaul. A total of 15 simulated standard overhaul environments were created by burning household materials. Sampling was conducted using mannequin heads fitted with full facepiece respirators with either a CBRN canister or SCBA. In-mask and personal samples were collected for aldehydes, polynuclear aromatic hydrocarbons, inorganic acids, aromatic hydrocarbons, nitrogen dioxide, and particulate matter. An additional six simulated high-exposure overhaul environments were created in a flashover chamber by continuously adding household materials to a smoldering fire. The sampling train was the same for both the standard and high-exposure environments; however, the facepiece was sealed to the mannequin head in the high-exposure environments. In the standard overhaul environment, the CBRN canister effectively reduced the level of exposure for most contaminants, while in the high-exposure overhaul exposure setting in-mask acetaldehyde and formaldehyde were detected. In both exposure settings, the SCBA prevented almost all exposure, and therefore remains the recommended respiratory protection during overhaul.

A New Miniature Respirable Sampler for In-mask Sampling: Part 2-Tests Performed Inside the Mask.

This paper is the second in a series of two describing the performance of a miniature and low-weight respirable sampler designed to fit inside filtering facepiece (FFP) and half-mask type respirators. The first paper described the design of the miniature sampler and evaluated the particle and collection performance of the miniature sampler. This paper assesses its comparability with the traditional inward leakage measurement technique, and its safe use. Simultaneous mass measurements of a respirable sodium chloride aerosol were taken inside a total inward leakage chamber by a miniature sampler and by sodium flame photometry. Direct side-by-side comparison of the two methods yielded excellent correlation (R 2 = 0.99), as did comparison when sampling from inside four different masks when worn by a breathing Sheffield dummy head. In addition, comparison tests were carried out using three models of FFP worn by human volunteers both with and without the miniature sampler, in order to test whether or not the presence of the miniature sampler negatively affected the protection offered. The difference between the tests carried out with the miniature sampler and without the miniature sampler was not statistically significant (P = 0.3). In all cases, the masks performed within their protection class, whether the miniature sampler was fitted or not. We therefore conclude that the miniature sampler does not significantly affect the protection offered by the masks. The miniature sampler may prove a viable option for in-mask measurements of respirable dust where low air concentrations of hazardous material are expected.

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. Respirator quantitative fit testing was done before and after exercise. RESULTS: There was no significant difference in pass rates for both FFRs on initial fit testing, but subjects who passed were more likely to fail the postexercise test with N95 FFRs (P = .01). Wearing FFRs increased the temperature of facial skin covered by the FFR (P = .009) and breathing discomfort (P = .002). No significant differences were noted in other measured variables (heart rate, respiratory rate, oxygen saturation, transcutaneous carbon dioxide level, rectal temperature, global skin temperature, core temperature, and subjective perceptions) between controls and FFRs and between FFR models. CONCLUSION: After 1 hour of exercise in hot, humid ambient conditions, P100 FFRs retained better fit than N95 FFRs, without additional physiologic or subjective impact. Wearing FFRs under these conditions does not add to the body's thermophysiologic or perceptual burdens.

Effect of upper strap downward displacement on n95 filtering facepiece respirator fit factors: a pilot study.

Fifteen subjects underwent three replicates of quantitative respirator fit-testing with N95 filtering facepiece respirators that were donned with the upper strap high on the occiput, as per the manufacturers' donning instructions. Each fit-test was immediately followed by repeat fit-testing with the upper strap downwardly displaced to the level of the ear sulcus to determine any change in fit factors that might occur with upper strap downward slippage. A total of 35/45 (78%) initial fit-tests had a passing score (fit factor ≥ 100) with the top strap high on the occiput and 33/35 (94%) of these passed subsequent fit-testing after the top strap was displaced downward to the ear sulcus. Geometric mean fit factors for the initial passed fit-tests, and following downward strap displacement, were 217 ± 1.6 and 207 ± 1.9, respectively (p = 0.64). Downward displacement of the top strap did not significantly impact fit factors of N95 FFRs that had previously passed fit-testing.