N95 respirator reuse, decontamination methods, and microbial burden: A randomized controlled trial.

PURPOSE: To evaluate the effectiveness and ease of N95 respirator decontamination methods in a clinic setting and to identify the extent of microbial colonization on respirators associated with reuse. METHODS: In a prospective fashion, N95 respirators (n = 15) were randomized to a decontamination process (time, dry heat, or ultraviolet C light [UVC]) in outpatient clinics. Each respirator was re-used up to 5 separate clinic sessions. Swabs on each respirator for SARS-CoV-2, bacteria, and fungi were obtained before clinic, after clinic and post-treatment. Mask integrity was checked after each treatment (n = 68). Statistical analyses were performed to determine factors for positive samples. RESULTS: All three decontamination processes reduced bacteria counts similarly. On multivariate mixed model analysis, there were an additional 8.1 colonies of bacteria (95% CI 5.7 to 10.5; p < 0.01) on the inside compared to the outside surface of the respirators. Treatment resulted in a decrease of bacterial load by 8.6 colonies (95% CI -11.6 to -5.5; p < 0.01). Although no decontamination treatment affected the respirator filtration efficiency, heat treatments were associated with the breakdown of thermoplastic elastomer straps. Contamination with fungal and SARS-CoV-2 viral particles were minimal to non-existent. CONCLUSIONS: Time, heat and UVC all reduced bacterial load on reused N95 respirators. Fungal contamination was minimal. Heat could permanently damage some elastic straps making the respirators nonfunctional. Given its effectiveness against microbes, lack of damage to re-treated respirators and logistical ease, UVC represents an optimal decontamination method for individual N95 respirators when reuse is necessary.

Hearing and Mortality Outcomes following Temporal Bone Fractures.

The aim of this article is to determine hearing and mortality outcomes following temporal bone fractures. Retrospective chart review was performed of 152 patients diagnosed with a temporal bone fracture presenting to the emergency room at a tertiary care referral center over a 10-year period. Utilizing Patients' previously obtained temporal bone computed tomographic scans and audiograms, fractures were classified based on several classification schemes. Correlations between fracture patterns, mortality, and hearing outcomes were analyzed using χ2 tests. Ossicular chain disruption was seen in 11.8% of patients, and otic capsule violation was seen in 5.9%; 22.7% of patients presented for audiologic follow-up. Seventeen patients with conductive hearing loss had air-bone gaps of 26 ± 7.5 dB (500 Hz), 27 ± 6.8 dB (1,000 Hz), 18 ± 6.2 dB (2,000 Hz), and 32 ± 7.7 dB (4,000 Hz). Two cases of profound sensorineural hearing loss were associated with otic capsule violation. No fracture classification scheme was predictive of hearing loss, although longitudinal fractures were statistically associated with ossicular chain disruption ( p < 0.01). Temporal bone fractures in patients older than 60 years carried a relative risk of death of 3.15 compared with those younger than 60 years. The average magnitude of conductive hearing loss resulting from temporal bone fracture ranged from 18 to 32 dB in this cohort. Classification of fracture type was not predictive of hearing loss, despite the statistical association between ossicular chain disruption and longitudinal fractures. This finding may be due to the low follow-up rates of this patient population. Physicians should make a concerted effort to ensure that audiological monitoring is executed to prevent and manage long-term hearing impairment.

Anatomic Variations in Temporal Bones Affect the Intensity of Nystagmus During Warm Caloric Irrigation.

HYPOTHESIS: Anatomic variables within the mastoid will correlate with intensity of caloric responses. BACKGROUND: During caloric irrigation, heat is transferred from the external auditory canal to the lateral semicircular canal (LSCC) through aerated mastoid bone. Temporal bone airspace volume and bone volume vary widely but the effect of this variation on caloric irrigation testing is not well characterized. Understanding this effect is necessary to understand how mastoid surgery may alter caloric irrigation results. METHODS: Twenty-two mastoid airspace and bones, as well as LSCC, were reconstructed from computed tomography scans of 11 subjects with normal anatomy who underwent vestibular function evaluation. Respective surface area (SA) and volume (V) of the mastoid airspace, bones, LSCC, and distance from LSCC to tympanic membrane (LSCC-TM) were calculated. In addition, computed values from these anatomic structures were correlated with the maximum velocity of slow phase nystagmus during warm caloric irrigation (MVwarm). RESULTS: Our results showed that the combined effect of airspace SA:V, bone SA:V, LSCC SA:V, and LSCC-TM distance accounted for 69.5% of the variation in MVwarm. Airspace SA:V (R = 0.22) and LSCC SA:V (R2 = 0.02) positively correlated with MVwarm, while bone SA:V (R = 0.17) demonstrated an inverse correlation with MVwarm. CONCLUSION: Preliminary results from this pilot study suggest that a substantial amount of the variability in MVwarm can be explained by temporal bone anatomy. Results also indicate that the denser the bone, the more heat is transferred to the LSSC, whereas increased airspace serves as an insulator. A larger study is necessary to confirm our findings.

Characterizing human nasal airflow physiologic variables by nasal index.

Although variations in nasal index (NI) have been reported to represent adaptation to climatic conditions, assessments of NI with airflow variables have not been rigorously investigated. This study uses computational fluid dynamics modeling to investigate the relationship between NI and airflow variables in 16 subjects with normal nasal anatomy. Airflow simulations were conducted under constant inspiratory pressure. Nasal resistance (NR) against NI showed weak association from nostrils to anterior inferior turbinate (R(2)=0.26) and nostril to choanae (R(2)=0.12). NI accounted for 38% and 41% of the respective variation in wall shear stress (WSS) and heat flux (HF) at the nasal vestibule, and 52% and 49% of variability in WSS and HF across the entire nose. HF and WSS had strong correlation with NI<80, and weakly correlated with NI>80; these differences in HF and WSS for NI<80 and NI>80 were not statistically significant. Results suggest strong relationship between NI and both WSS and HF but not NR, particularly in subjects with NI<80.

A Systematic Review of Diuretics in the Medical Management of Ménière's Disease.

OBJECTIVE: (1) Review evidence for the use of oral diuretic medications in the management of Ménière's disease. (2) Analyze therapy-related hearing and vertigo outcomes. DATA SOURCES: Literature was obtained through directed searches of MEDLINE, EMBASE, Web of Science, EBSCO Host, Cochrane Reviews, and linked citations through seminal papers. We searched independent electronic databases for articles that reported the use of diuretics in patients with Ménière's disease. REVIEW METHODS: All articles of level 4 evidence or higher, per the Oxford Centre for Evidence-Based Medicine, were included with no limit for number of patients, duration of therapy, or follow-up period. Two independent investigators reviewed the articles for inclusion eligibility. Outcomes were tabulated, including subjective or quantitative measures of hearing, tinnitus, vertigo episode frequency, and medication adverse effects. RESULTS: Nineteen articles were included from 1962 to 2012 from 11 countries. Twelve retrospective case series, 4 randomized controlled trials, 2 case-control trials, and 1 prospective case series were identified. Six studies investigated isosorbide; 5, hydrochlorothiazide; 2, acetazolamide; 2, chlorthalidone; and 1 each of betahistine, hydrochlorothiazide, chlorthalidone, acetazolamide, hydrochlorothiazide-triamterene, and nimodipine. Eight (42.1%) studies reported hearing outcomes improvement. Fifteen (79.0%) studies reported vertigo outcomes improvement. Ten (52.6%) studies reported no side effects, and 4 studies (21.1%) reported abdominal discomfort. No significant morbidity or mortality was reported in any study. CONCLUSION: Multiple low evidence-level studies report that oral diuretic therapy may be beneficial in the medical management of Ménière's disease. Improvement in vertigo episode frequency was consistently reported, with less convincing evidence for improvement in hearing outcomes.

A Computational Study of Nasal Spray Deposition Pattern in Four Ethnic Groups.

BACKGROUND: Very little is known about the role of nasal morphology due to ethnic variation on particle deposition pattern in the sinonasal cavity. This preliminary study utilizes computational fluid dynamics (CFD) modeling to investigate sinonasal airway morphology and deposition patterns of intranasal sprayed particles in the nose and sinuses of individuals from four different ethnic groups: African American (Black); Asian; Caucasian; and Latin American. METHODS: Sixteen subjects (four from each ethnic group) with "normal" sinus protocol computed tomography (CT) were selected for CFD analysis. Three-dimensional reconstruction of each subject's sinonasal cavity was created from their personal CT images. CFD simulations were carried out in ANSYS Fluent(™) in two phases: airflow phase was done by numerically solving the Navier-Stokes equations for steady state laminar inhalation; and particle dispersed phase was solved by tracking injected (sprayed) particles through the calculated airflow field. A total of 10,000 particle streams were released from each nostril, 1000 particles per diameter ranging from 5 µm to 50 µm, with size increments of 5 µm. RESULTS: As reported in the literature, Caucasians (5.31 ± 0.42 cm(-1)) and Latin Americans (5.16 ± 0.40cm(-1)) had the highest surface area to volume ratio, while African Americans had highest nasal index (95.91 ± 2.22). Nasal resistance (NR) was highest among Caucasians (0.046 ± 0.008 Pa.s/mL) and Asians (0.042 ± 0.016Pa.s/mL). Asians and African Americans had the most regions with particle deposition for small (5 µm-15 µm) and large (20 µm-50 µm) particle sizes, respectively. Asians and Latin Americans individuals had the most consistent regional particle deposition pattern in the main nasal cavities within their respective ethnic groups. CONCLUSIONS: Preliminary results from these ethnic groups investigated showed that Caucasians and Latin Americans had the least patent nasal cavity. Furthermore, Caucasians and African Americans had the lowest inter-subject consistency in regional particle deposition pattern; this may be due to greater inter-subject variability in their respective nasal vestibule morphology.

A Video-Based Module for Teaching Communication Skills to Otolaryngology Residents.

OBJECTIVE: To determine whether instructional videos modeling examples of "good" and "bad" patient communication skills are useful as an educational tool for improving resident-patient communication. DESIGN: Retrospective study in which resident participants in the module gave survey responses indicating perceived utility of the exercise. SETTING: Tertiary academic medical center. PARTICIPANTS: A total of 11 otolaryngology trainees from postgraduate year 1-5 who attended the course over 2 separate sessions and provided feedback on the benefits of the module. RESULTS: All 11 residents attended both sessions. Of 22 total survey responses, 21 found that the videos were "realistic and engaging" and were a true representation of commonly encountered clinical scenarios. Residents identified multiple themes and behaviors distinguishing "good" vs "bad" communication with patients and felt they could incorporate these into daily practice. A perceived weakness was the lack of opportunity for "role playing" with a video-based module as opposed to standardized patients. CONCLUSIONS: Instructional videos, when realistic, are useful for modeling effective patient communication skills for residents. By watching the videos, residents are able to identify specific techniques they can incorporate into their daily practice.

High polar content of long buried blocks of sequence in protein domains suggests selection against amyloidogenic non-polar sequences.

Native protein structures achieve stability in part by burying hydrophobic side-chains. About 75% of all amino acid residues buried in protein interiors are non-polar. Buried residues are not uniformly distributed in protein sequences, but sometimes cluster as contiguous polypeptide stretches that run through the interior of protein domain structures. Such regions have an intrinsically high local sequence density of non-polar residues, creating a potential problem: local non-polar sequences also promote protein misfolding and aggregation into non-native structures such as the amyloid fibrils in Alzheimer's disease. Here we show that long buried blocks of sequence in protein domains of known structure have, on average, a lower content of non-polar amino acids (about 70%) than do isolated buried residues (about 80%). This trend is observed both in small and in large protein domains and is independent of secondary structure. Long, completely non-polar buried stretches containing many large side-chains are particularly avoided. Aspartate residues that are incorporated in long buried stretches were found to make fewer polar interactions than those in short stretches, hinting that they may be destabilizing to the native state. We suggest that evolutionary pressure is acting on non-native properties, causing buried polar residues to be placed at positions where they would break up aggregation-prone non-polar sequences, perhaps even at some cost to native state stability.