N95口罩效能影響因子測試研究

本研究主要目的為利用微生物鑑定質譜儀（matrix-assisted laser desorption ionization-time of flight, MALDI Biotyper ），檢測口罩上殘存微生物狀態，依據CNS14755「拋棄式防塵口罩」規範，以自動濾材測試機（automated fiter tester, TSI, model 8130），檢測不同效期的N95口罩對氣膠（aerosol）在最易穿透粒徑（most penetrating particle size, MPS）之過濾效率（filtration efficiency）及呼吸阻抗（breathing resistance），並計算其過濾品質（quality factor, qf），依據對可能改變口罩纖維帶電特性的原因進行效能評估，例如：高溫高壓滅菌（Autoclave）、γ（Gamma）射線照射滅菌方式對貫穿率、阻抗及過濾品質之影響；另外依據CNS14776醫用面罩對合成血液穿透阻力的實驗法，實驗目前醫療單位使用之N95口罩是否通過合成血液噴濺測試。根據實驗結果，不管是效期內或過期之口罩均檢測出細菌殘存，所檢出之菌落以仙人掌桿菌（Bacillus cereus）佔45%最多，糞腸球菌（Enterococcus faecalis）佔5%。在不同儲存年限之N95口罩經統計分析顯示：一、貫穿率在儲存年限上有統計顯著差異（P=0.0453），效期內（new）的口罩貫穿率比屆期（expired）的低，收集效率較佳；在阻抗方面，儲存年限也有統計顯著差異（P=0.0082），效期內的阻抗較強。二、效期內口罩以經過高溫高壓滅菌後與沒有經過滅菌相比，貫穿率變高、過率品質降低；而以Gamma進行口罩滅菌，不論是10 kGY 、25 kGY或30 kGY之Gamma劑量，與沒有經過滅菌相比較，貫穿率上升，阻抗變高、過率品質皆降低。三、在相同滅菌處理的情況下，不同儲存年限口罩在貫穿率、阻抗與過濾品質上沒有太大的差異，僅有經過高溫高壓滅菌處理之效期內口罩，較屆期口罩阻抗降低，達統計上顯著差異（p=0.0282）。四、合成血液噴濺測試結果，屆期N95口罩通過率97.9 %，是否滅菌並不影響其防血液噴濺滲透之效果。屆期N95口罩性能仍大致符合口罩之過濾及呼吸阻抗標準，因此儲存時間雖達統計顯著，但仍並非主要影響濾材帶電特性及過濾品質之因子。而以Gamma滅菌方式影響濾材之帶電特性及過濾品質較為強烈，未來仍須進一步研究確認。

This study was to test the survival of microorganisms using matrix-assisted laser desorption ionization-time of flight (MALDI Biotyper) and test the filtration efficiency and breathing resistance of N95 respirators of different storage periods using the most penetrating particle size (MPS) aerosol by automated fiter tester （TSI, model 8130）according to the regulation of CNS14755 for “Disposable dust respirators”. Quality factor (qf）was calculated to access possible effects of storage conditions and disinfection methods such as Autoclaving and γ（Gamma irradiation）on the electric quality of fibers of the respirators. The purpose was to evaluate the effects methods of sterilization on the penetration, breathing resistance and filtration quality of the respirators. In addition, the study also tests the N95 respirators according to the regulation of CNS14776 “Method of test for resistance of medical face masks to penetration by synthetic blood”.According to study results, all respirators within or outside their valid storage dates are not totally aseptic. Among the bacteria cultured, the most often founded are Bacillus cereus (45%), and Enterococcus faecalis (5%). The analysis of N95 respirators with different storage conditions revealed that: 1. A significant statistical difference （P=0.0453） was noted in aerosol filtration efficiency among N95respirators of various storage periods, and the penetration rate was lower in respirators within the valid date (new) compared with those respirators already out of their valid dates (expired). There was also a statistical significance（P=0.0082）in breathing resistance among various storage periods. 2. Autoclaving method of disinfection increased penetration, decreased quality factor in respirators within valid dates when compared with those without disinfection. The doseage of 10 kGY, 25 kGY or 30 kGY Gamma radiation also increased penetration, resistance and decreased quality factor. 3.There was no significant difference on penetration, resistance and quality factor between respirators within or outside the valid dates when they were treated with the same disinfection methods except that after autoclave, respirators within valid date have significant lower breathing resistance compared with the expired respirators（p=0.0282）. 4. N95 respirators outside the valid dates pass the synthetic blood penetration test, and the pass rate is 97.9 %. The methods of disinfection did not affect the effect of preventing blood penetration.The performance of expired N95 respirators still satify the requirements of filtration efficiency and breathing resistance. Althrough the various storage periods of N95 respirators reveal statistical significance, however, this is not the major affecting factor of filters fiber charge and filter quality. The method of Gamma irradiation appears stronger than storage period and autoclave method in affecting filters fiber charge and filter quality. The study still needs further confirmation.