Respiratory Protective Devices

BACKGROUND: This study purposed to survey the fit rate of respirators by person and by product through conducting a qualitative fit test of high-efficiency respirators; moreover, this study also tests for differences in the fit rates determined by the qualitative fit tests with an increase in the number of the types of respirators tested. METHODS: The subjects of this study were 30 healthcare personnel who had passed a sensitivity test. The fit test of high-efficiency respirators was conducted using FT10 (3M Co., USA), an experimental tool used for performing the qualitative fit test of high-efficiency respirators, and three types of high-efficiency respirators - 1860, PFR95, and N7000 - were tested. RESULTS: The qualitative fit test was performed for the three types of high-efficiency respirators and the fit rate of the respirators that the subjects had been using previously was 43.3%; however, the probability that one or more of the three types of high-efficiency respirators would fit the subjects increased to 83.3%, and this increase was statistically significant (P<0.05). The difference in the fit rates of the three types of high-efficiency respirator types was not statistically significant; however, the differences in the satisfaction of and preference for the different respirator products were all statistically significant (P<0.05). CONCLUSION: Healthcare personnel are using ill-fitting respirators and a qualitative fit test should be performed to improve the fit of their respirator. In the qualitative fit test performed for the high-efficiency respirators, the fit rate increased with the increase in the variety of respirator types. Thus, a large variety of respirators should be made available to increase the fit rate of high-efficiency respirators for healthcare personnel.
Delivery of Health Care ; Humans ; Respiratory Protective Devices ; Ventilators, Mechanical

Coronavirus Infections ; prevention & control ; Humans ; Masks ; Respiratory Protective Devices

Coronavirus Infections ; prevention & control ; Humans ; Masks ; Respiratory Protective Devices

OBJECTIVEThe objective of this study was to investigate the aspiratory resistance, filtration penetration and their influence factors of N95 filtering-facepiece respirators used widely in China.

METHODSThe total of 6 brands and 21 models of N95 filtering-facepiece respirators which are certified and big sales on the market. The aspiratory resistance and filtration efficiency filter penetration were measured while air pump ran from 10 L/min to 100 L/min using differential pressure gauge and the PortaCount, respectively.

RESULTSThe filtration penetrations for 2 of the 21 models were lower than 95%, and the qualified rate for all models was 90.47%. The filtration penetrations gradually decreased when ventilation flow of air pump increased. The negative correlation was observed between filtration penetration and ventilation flow (r(2) = 0.711, P < 0.05). The resistances of all 21 models of N95 respirators met the requirements of the national standard. The aspiratory resistance started to elevate with the increasing of ventilation flow, and a positive correlation between both (r(2) = 0.878, P < 0.05). Significant differences of filtration penetration and aspiratory resistance were observed among between different brands (P < 0.05) although no differences of filtration penetration existed among different models of one brand (P > 0.05). But the differences of the aspiratory resistance among different models of one brand were statistically significant (P < 0.05).

CONCLUSIONThe aspiratory resistances of all N95 filtering-facepiece respirators used in this study met the requirements of the national standard. And the qualified ratio of filtration penetration of all models was higher than 90%. The influencing factors of aspiratory resistance included materials, size and ventilation flow. And influencing factors for filtration penetration were materials and ventilation flow.

Air Pollutants, Occupational ; China ; Equipment Design ; Filtration ; instrumentation ; Masks ; standards ; Materials Testing ; Respiratory Protective Devices ; standards

Humans ; Occupational Exposure ; prevention & control ; Respiratory Protective Devices ; classification ; standards ; utilization ; United States

OBJECTIVETo develop two new respirator fit test panels using data from anthropometric survey of Chinese adult workers: bivariate panel and principal component analysis (PCA) panel for meeting the requirements of respirator fit design and testing and evaluate the applicability of the two different fit test panels for current Chinese workers.

METHODSAn anthropometric database based upon anthropometric data of current Chinese workers was used for panel design. The bivariate panel was based upon the bivariate distribution of the face length and face width measurements, and the PCA panel was developed using principal components analysis of 10 stable facial dimensions (minimum frontal breadth, face width, bigonial breadth, face length, interpupillary distance, head breadth, nose protrusion, nose breadth, nasal root breadth, subnasale-sellion length). The distribution of Chinese workers across the panels was used to analyze the panels' applicability for Chinese workers.

RESULTSThe bivariate panel and PCA panel developed in this study consisted of 10 cells and 8 cells respectively, covered 96.9% (male 95.4%, female 98.4%) and 96.5% (male 95.1%, female 98.1%) of the current Chinese workers, respectively. The distribution of workers across both panels was uniform. Each cell contained 4.6% - 21.7% of the population in the bivariate panel and 10.4% - 14.6% of the population in the PCA panel. The LANL full-face piece respirator fit test panel covered only 70.9% of the Chinese workers, It was thought to be no longer adequate for the Chinese adult workers.

CONCLUSIONNew respirator fit test panels based on updated anthropometric database and distributions specific to Chinese workers may be more beneficial for applications in China.

Adult ; China ; Equipment Design ; Female ; Humans ; Male ; Principal Component Analysis ; Reference Values ; Respiratory Protective Devices

The positive pressure powered air-filter protective hood can prevent physicians and nurses from being infected by serious respiratory infections. The contaminated air is filtered by the high efficiency specific air-filter (HESA) and then transported into the hood by a blower to form about 140 +/- 10 Pa positive pressure environment, which makes the air in hood overflow out from the lower part of the hood, by which carbon dioxide and vapor can be removed, and excreted. The HESA's filters of simulative virus up to 99.9999% with the structure of double layers filtering. With going at 4 km/h pace on a walking vehicle wearing the hood, the testees' heart rate is 90-105/min oxygen saturation of the blood(SPO2) is 97%-98%. When the air flow is from 75 L/min to 125 L/min, this can meet the testees' physiological demand under heavy workload. Clinical trial results show that the hood can effectively protect the physicians and nurses from infection.
Adult ; Equipment Design ; Female ; Filtration ; instrumentation ; Humans ; Male ; Middle Aged ; Respiratory Protective Devices

INTRODUCTION: During the coronavirus disease 2019 (COVID-19) pandemic, multiple guidelines have recommended videolaryngoscope (VL) for tracheal intubation. However, there is no evidence that VL reduces time to tracheal intubation, and this is important for COVID-19 patients with respiratory failure. METHODS: To simulate intubation of COVID-19 patients, we randomly assigned 28 elective surgical patients to be intubated with either McGrath™ MAC VL or direct laryngoscope (DL) by specialist anaesthetists who donned 3M™ Jupiter™ powered air-purifying respirators (PAPR) and N95 masks. The primary outcome was time to intubation. RESULTS: The median time to intubation was 61 s (interquartile range [IQR] 37-63 s) and 41.5 s (IQR 37-56 s) in the VL and DL groups, respectively ( P = 0.35). The closest mean distance between the anaesthetist and patient during intubation was 21.6 ± 4.8 cm and 17.6 ± 5.3 cm in the VL and DL groups, respectively ( P = 0.045). There were no significant differences in the median intubation difficulty scale scores, proportion of successful intubations at the first laryngoscopic attempt and proportion of intubations requiring adjuncts. All the patients underwent successful intubation with no adverse event. CONCLUSION There was no significant difference in the time to intubation of elective surgical patients with either McGrath™ VL or DL by specialist anaesthetists who donned PAPR and N95 masks. The distance between the anaesthetist and patient was significantly greater with VL. When resources are limited or disrupted during a pandemic, DL could be a viable alternative to VL for specialist anaesthetists.
Humans ; COVID-19 ; Intubation, Intratracheal ; Laryngoscopes ; Laryngoscopy ; Respiratory Protective Devices ; Video Recording

OBJECTIVETo study the filtration efficiency of a positive pressure powered air purifying medical protective equipment and the effect of the flow rate on the microenvironment of the equipment.

METHODSThe filtration efficiency of high efficiency particulate air (HEPA) filter was measured with the biologic aerosol of simulating virus (Escherichia coli bacteriophage f(2)). The simulation work was done at the walk rate of 4 km/h in summer. The effect of the flow rate on the oxygen content, the carbon dioxide content, the temperature and the humidity of the microenvironment of the equipment was investigated. The clinical experiments were conducted in three appointed hospital for fighting against SARS.

RESULTSThe HEPA filter could filtrate 99.99% simulating viruses in the air. When the flow rate ranged from 75 to 125 L/min, the microenvironment parameters of the equipment were: the oxygen content was between 19.6% and 20.1% (the physiological safety limit is more than 14.6%); the carbon dioxide content ranged from 0.43% to 0.57% (the physiological safety limit is less than 1.0%); the temperature was between 32.0 degrees C to 32.2 degrees C; the humidity ranged from 49.7% to 59.4% (the physiological safety limit is the temperature 31 degrees C and the humidity 85% or temperature 38 degrees C and humidity 50%). Each microenvironment parameter met the demand of a healthy person under the normal workload. In the clinical experiments, the doctors wearing the equipment who performed the tracheotomy for a SARS patient in a deep coma were not infected.

CONCLUSIONThe medical protective equipment can protect the doctor and nurse in SARS contaminated areas effectively and improve their work conditions.

Air ; analysis ; Air Microbiology ; Carbon Dioxide ; analysis ; Colony Count, Microbial ; Humans ; Humidity ; Occupational Medicine ; instrumentation ; Oxygen ; analysis ; Protective Devices ; Respiratory Protective Devices ; Temperature ; Ventilation