ABSTRACT
Objective To investigate the security of mechanical filter in mechanical ventilation for ICU patients.Methods 60 patients treated with mechanical ventilation and conventional airway humidification were selected and randomly divided into treatment group(mechanical filter treatment) and control group(non filter treatment) ,30 cases in each group.The changes of respiratory function(airway plateau pressure,endogenous PEEP and arterial carbon dioxide partial pressure of 2h,12h,24h at the first day of mechanical ventilation) ,and the incidence and mortality of ventilator-associated pneumonia were observed.Results The study showed airway resistance and the work of breathing in treatment group did not increase,and no hypercapnia due to congestion occurred.The incidence of ventilator-associated pneumonia in treatment group was significantly lower than that of the control group (26.7% vs 56.7% ,x2 = 5.554,P = 0.018).Conclusion Mechanical filer applied in patients with mechanical ventilation was safe and could decrease the incidence of ventilator-associated pneumonia.
ABSTRACT
O uso de filtros e respiradores contra particulados é extremamente comum na indústria em geral. As normas utilizadas para a avaliação desses equipamentos definem critérios de testes e aprovação que visam garantir que os filtros continuem eficientes ao longo do tempo. Fatores como tipo, tamanho, velocidade, carga da partícula e temperatura são, em geral, considerados nos testes de aprovação. O objetivo deste artigo foi verificar o comportamento de filtros para particulados tipo eletreto usados em respiradores, expostos às condições térmicas semelhantes às encontradas em ambiente de trabalho. Simularam se, em laboratório, a temperatura e o tempo de exposição a que os mesmos podem estar sujeitos, medindo e comparando os resultados obtidos no sentidode atenderem as recomendações normativas, tanto nacionais como internacionais.Filtros e peças faciais de diferentes fabricantes foram expostos adiferentes temperaturas, sendo mantidos nestas por, no mínimo, 24 horas.Testes de penetração utilizando vazão de 85 l/min e partículas de NaCl,da ordem de 0,3 a 0,6 ?m, que são consideradas as Partículas de Tamanhos Mais Penetrantes (MPPS), foram realizados antes e depois de cada período de exposição. A menor e a maior variações encontradas foram de 2,53% até 18%, respectivamente.
Particle filters are very commonly used in industries in general. The standards adopted for the approval of these filters define tests and approval criteria aiming at guaranteeing the efficiency of the filters in the long run. Facts such as: type, size, speed, particle charge and temperature are considered on the approval tests. This article aims at checking the way eletrect particulated filters for respirators act when exposed to similar thermal conditions as the ones found in work environment. This was obtained by simulating in lab the temperature andtime of exposure the respirators could be subjected to and by measuring and comparing the results in order to comply with both national and international standards recommendations. Filters and face pieces from different manufactures were tested in different temperatures and maintained under these conditions for at least 24-hours. Penetration tests were held before and after each period of exposure using 85 l/min flow rate and 0.3 to 0.6 ?m NaCl particles, which are considered the Most Penetranting Particle Size (MPPS). The smallest and largest variations found were 2.53% to 18%, respectively.