Background: HFNC system is a novel device used with aerosol therapy and seems to be rapidly accepted. Although there are some studies conducted on HFNC and vibrating mesh nebulizer, the effect of HFNC on aerosol delivery using jet nebulizer or pressurized metered-dose inhaler (pMDI) has not been reported. In an effort to examine the effect of HFNC on aerosol deposition, this study was conducted to quantify aerosol drug delivery with or without a HFNC using either pMDI or jet nebulizer. Methodology: The SAINT model, attached to an absolute filter (Respirgard II, Vital Signs Colorado Inc., Englewood, CO, USA) for aerosol collection, was connected to a pediatric breathing simulator (Harvard Apparatus, Model 613, South Natick, MA, USA). To keep the filter and the SAINT model in upright position to collect aerosolized drug, an elbow adapter was connected between the absolute filter and the breathing simulator. An infant HFNC (Optiflow, Fisher & Paykel Healthcare LTD., Auckland, New Zealand) ran at 3 l/min O2 was attached to the nares of the SAINT model. Breathing parameters used in this study were Vt of 100 mL, RR of 30 breaths/min, and I:E ratio of 1: 1.4. Aerosol drug was administered using: 1) Misty-neb jet nebulizer (Allegiance Healthcare, McGaw Park, Illinois, USA) powered by air at 8 l/min using pediatric aerosol facemask (B&F Medical, Allied Healthcare Products, Saint Louis, MO, USA) to deliver albuterol sulfate (2.5 mg/3 mL NS), and 2) Four actuations of Ventolin HFA pMDI (90 μg/puff) (GlaxoSmithKline, Research Triangle Park, NC, USA) combined with VHC (AeroChamber plus with Flow-Vu, Monaghan Medical, Plattsburgh, NY, USA). Aerosol was administered to the model with and without the HFNC and another without (n=3). Drug was collected on an absolute filter, eluted and measured using spectrophotometry. Independent t tests were performed for data analysis. Statistical significance was determined with a p value of <0.05. Results: The mean inhaled mass percent was greatest for pMDI with (p = 0.0001) or without HFNC (p = 0.003). Removing HFNC from the nares before aerosol treatment trended to increase drug delivery with the jet nebulizer (p = 0.024), and increased drug delivery by 6 fold with pMDI (p = 0.003). Conclusions: Aerosol drug may be administered in pediatrics receiving HFNC therapy using either jet nebulizer or pMDI. However, using pMDI, either with or without HFNC, is the best option. When delivering medical aerosol by mask, whether by jet nebulizer or pMDI, removing HFNC led to an increase in inhaled mass percent. However, the benefit of increased aerosol delivery must be weighed against the risk of lung derecruitment when nasal prongs are removed.

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<p>Evidence exists for the airborne transmission of contagious pathogens such as SARS-CoV-2, influenza A virus and <i>Mycobacterium</i> <i>tuberculosis</i> in indoor environments. These pathogens are carried in the respiratory droplets and transmitted through airborne route to infect individuals. An important element in risk assessment for pathogenic bioaerosol exposure is a determination of the inhaled deposited dose rate – the number of deposited pathogenic particles per minute – received by each respiratory region and the fractional reduction of dose rate by different material facemasks. This paper presents an aerosol physics-based modeling framework to estimate the fractional reduction of regional dose rate in diverse indoor healthcare environments. The fractional reduction of dose rate is a useful metric to evaluate the facemask effectiveness in reducing the inhaled dose rate. Data extraction of pathogenic bioaerosol size distributions and size-dependent facemask filtration efficiency curve combined with deposition fraction model become the baseline to calculate the fractional reduction of dose rate by 10 different facemasks. Facemask leakage is also considered for the realistic representation of its impact on reduction fraction as current studies focus on mask material filtration efficiency. This analysis considers how the fractional reduction of dose rate is influenced by the pathogenic bioaerosol size distribution, age-dependent respiratory parameters, age-specific deposition fraction, facemask filtration efficiency and mask leakage. Different factors drove variations in the reduction fraction of various sized-pathogenic bioaerosols received by each respiratory region for each age group. This framework can be a useful tool for decision-makers in evaluating the mask’s effectiveness in reducing deposition of pathogenic bioaerosols.</p>

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Introduction: Treatment with Rapid Maxillary Expansion (RME) and Facemask Therapy (FM) has been reported as one of the most effective forms of treatment for patients with Class III malocclusion, with maxillary involvement. Objective: To evaluate the cephalometric changes in the facial tegumentary in patients with malocclusion of skeletal Class III with maxillary retrusion, with greater or less extent, immediately after orthopaedic therapy, with RME/FM. Methods: The treatments with RME/FM were performed by a single operator in a suitably selected sample (10 girls and 6 boys), whose the initial and final data were collected on two times (T0 and T1), evaluating cephalometric parameters and soft tissue. The experimental phase lasted about 12 months. The data were analyzed and compared statistically (Wilcoxon Test - SPSS 13.0), through descriptive analysis, on changes in facial tissue and bone, and dental conditions. Results: A significant increase in maxillary forward growth, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed. The maxillary incisors were significantly proclined and the mandibular incisors significantly retroclined. Conclusion: Changes produced in the midface were clinically and cephalometric observed, demonstrating anterior displacement of maxilla and point "A", improvement in facial convexity, correction of the anterior crossbite, increase in the overbite and overjet. However, more studies are needed, since the information in the literature are still inconclusive, given the divergent findings and consensus between authors. / Introdução: O tratamento Ortodôntico com Expansão Rápida da Maxila (ERM) e Tração Reversa (TR) tem sido descrito na literatura como uma das mais eficazes formas de tratamento, para pacientes portadores de má oclusão de Classe III, com envolvimento maxilar. Objetivo: Avaliar as alterações cefalométricas e no tegumento da facial, em pacientes portadores de má oclusão de Classe III esquelética, com retrusão maxilar em maior ou menor grau, imediatamente após o tratamento com ERM/TR. Metodologia: Os tratamentos com ERM/TR foram realizados pelo pesquisador, em uma amostra convenientemente selecionada, sem distinção de gênero (10 meninas e 6 meninos), jovens, com necessidade de tratamento, onde os dados iniciais e finais foram coletados em dois momentos (T0 e T1), avaliando parâmetros cefalométricos ósseos e de tecidos moles. O período experimental foi de aproximadamente 12 meses. Os resultados foram analisados e comparados estatisticamente (Teste de Wilcoxon - SPSS 13.0), por meio de análises descritivas, quanto às alterações ósseas e no tegumento facial, e quanto às modificações dentárias. Resultados: Significante aumento no crescimento anterior da maxila, limitação do crescimento anterior da mandíbula, rotação mandibular no sentido horário. Incisivos maxilares foram significativamente proclinados e incisivos mandibulares retroinclinados. Conclusão: As alterações produzidas na face média foram clinica e cefalometricamente observadas, demonstrando anteriorização da maxila e do ponto A , melhora na convexidade facial, correção do cruzamento anterior, viabilização de sobremordida e sobressaliência positivas. Entretanto, mais estudos são necessários, visto que as informações existentes na literatura ainda são pouco conclusivas, dadas as divergências de achados e de consenso entre autores.