| 摘要: | 本研究所針對之呼吸防護具係以一般工業最常用之濾毒罐式面罩與N95口罩為主，此兩種面罩均屬非動力(non-powered)密閉淨氣式呼吸防護具，N95口罩其面罩罩體本身即為淨氣單元，除了防塵之外，也可以作為醫護人員防護感染時使用。研究指出在被評估為需使用呼吸防護具之場所，僅有約20%至30%有提供呼吸防護具且被使用，造成使用者不願配戴呼吸防護具之原因可分為三大類，包括配戴時因為呼吸阻力、無效腔及防護具本身重量所增加之生理負荷、與使用者本身相關之心理因子（包含主觀不適）及因環境與防護具本身之所造成之熱負荷。
有關配戴密閉淨氣式濾毒罐面罩所造成之生理負荷研究資料較多，但N95口罩相關研究則相當缺乏，雖然其呼吸阻力較濾毒罐式防護具為低，但是在較長時間使用後，罩體本身會變得相當潮濕，呼吸阻力也會增加，值得加以評估。有關配戴呼吸防護具時之主觀不適缺乏系統性之研究，但相關研究均指出配戴呼吸防護具時之主觀不適對使用者之配戴行為具有關鍵性影響。
本研究包括兩個實驗，目的在瞭解配戴N95口罩與一般職業常用之濾毒罐式面罩在實際使用上之生理負荷與主觀不適之情況，進而討論其對使用者配戴行為之影響，第一部份之實驗為全罩式面罩與N95口罩之生理負荷與主觀不適評估，第二部分的實驗則進一步探討有閥與無閥之N95口罩在有無講話作業之生理負荷與主觀不適。
共有18位醫學大學學生完整參與此二部分實驗，男女各9名，平均年齡為24歲，第一部份之實驗獨立變數包括性別、呼吸防護具型式(包括全罩式面罩搭配化學濾毒罐及N95濾毒匣、N95球型有閥及無閥口罩)、工作負荷(輕度作業與中度作業)。第二部分之實驗獨立變數包括性別、N95口罩型式(N95船型有閥及無閥口罩)、工作負荷(輕度作業與中度作業)及作業類型（有講話與無講話），此兩部分實驗之獨立變數除性別外，均為受試者內因子設計，受試者會參與所有實驗條件之實驗。本研究兩個實驗所評估之應變數相同，包括工作時心跳、工作心跳、吸氣壓力、吐氣壓力、呼吸頻率、口罩內溫度、分通氣量、耗氧量與單位體重耗氧量等生理負荷指標及主觀不適問卷。
第一部分實驗結果顯示，配戴呼吸防護具會使工作時心跳與工作心跳明顯高於沒有配戴呼吸防護具時之相同負荷作業，但在不同型式呼吸防護具間無顯著差異，配戴呼吸防護具的吸氣壓力明顯隨防護具之吸氣阻力增加而增加，吸氣壓力為全罩式面罩搭配化學濾毒罐時最高，N95球型無閥口罩最低，吐氣壓力仍以全罩式面罩搭配化學濾毒罐時最高，但最低者為N95球型有閥口罩。在口罩內溫度的部分，則是N95口罩的溫度高於全罩式面罩，且無閥N95口罩高於有閥N95口罩，分通氣量及耗氧量的部分，全部皆是全罩式面罩高於N95口罩，在主觀不適部分，不同作業負荷有顯著差異，中度負荷的不舒服程度高於輕度負荷的不舒服程度，在不同呼吸防護具間僅有口罩內溫度之主觀不適有顯著差異，N95球型無閥口罩不舒適程度顯著高於其他三種呼吸防護具。
實驗二的結果顯示配戴有閥無閥的N95口罩不同型式之呼吸防護具對心跳的影響不大，但配戴N95船型無閥口罩在吸氣壓力、吐氣壓力及口罩內溫度的結果都顯著高於N95有閥口罩，因此在選擇N95船型口罩來作為呼吸防護具時，有閥會較無閥來的好。至於作業時有無講話則對心跳有很大的影響，每分鐘大約會增加3至4下的心跳，有講話作業在心跳、吸氣壓力、吐氣壓力、呼吸頻率顯著高於無講話作業。此外主觀不適問卷結果顯示，中度作業之不舒適程度會高於輕度作業，N95船型無閥口罩之不舒適程度會高於N95船型有閥口罩，溫度是主要造成配戴者不舒適的主因，有講話作業之不舒適程度會高於無講話作業，主觀不適問卷的結果皆與生理負荷指標之結果一致。
This study aim to evaluate the most frequently used non-powered tight-fitting air-purifying respirators with canister and N95 facemasks. The N95 facemask which the facepiece itself is the purifying element is also used by medical personnel. Research results have indicated the respirators are available and in use in only 20-30% of the work phases evaluated as needing them. Failure to use a respirator is influenced by the physiological burden caused by such as additional respiratory resistance and dead space, by psychological factors such as subjective discomforts, and by thermo stress caused by the environment and respirator itself.
There were lots of researches addressing the physiological effects whilst wearing respirators with canister. Only little research focused on N95 facemask which is associated with smaller breathing resistance when compared with respirator with canister. However, the N95 facemask is still need to be assessed because it may become wet and the breathing resistance may increase after prolonged use. The subjective discomfort associated with respirator wearing has not been studied systematically, but it is widely agreed that user’s discomfort represents a crucial issue to interfere with the use of respirators.
Two experiments were conducted in the present study. The study intended to assess the physiological loads and subjective discomforts and their effects on the wearing behaviour for non-powered tight-fitting air-purifying respirator with canister and N95 facemask. The first experiment aimed to evaluate and compare the physiological loads and subjective discomforts between N95 facemask and a full-facepiece respirator. The second experiment explored furthermore about the effects of wearing N95 facemask with or without expiratory valve and the effects of speaking or not while wearing the two types of N95 facemasks.
18 medical university students (9 males and 9 females) with mean age about 24 year olds completely participated in the two experiments. The evaluated independent variables in the first experiment included gender (GR), types of respirator (RT), including ball type N95 facemasks with/without valve (BWV, BNV), full-facepiece respirator with chemical canister or N95 filter(FWC, FWN) and work loads (WL, 45W and 85W). The explored independent variables in the second experiments included gender, types of respirator (ship-type N95 face mask with/without valve, SNV and SWV), work load (45W and 85W) and task (TK, speaking or not). All independent variables in the two experiments except gender were designed as within-subject variables. The evaluated dependent variables for the two experiments were identical which included working and work pulse, peak inspiratory and expiratory resistance (PIP, PEP), respiratory frequency (RF), temperature inside respirator (TIR), minute ventilation (VE), volume of oxygen consumption (VO2) and subjective rating of perceived exertion (RPE) for five categories.
Results of the first experiments showed that wearing respirators significantly increased the working pulse and work pulse. Both of the effects of RT on working and work pulse were not significant. The PIP and PEP measured for the four experiment respirators were consistent with the measured inspiratory and respiratory resistance for each respirator. The PIP value was the highest for FWC and was the lowest for BNV. The PEP value was the highest for FWC and was the lowest for BWV. The TIR for BNV was the highest followed by BWV and were significantly higher than FWC and FWN. The VE and VO2 for FWC and FWN were significantly higher the BWV and BNV. The effects of WL on the five RPEs were all significant. As for the effects of RT on RPE, only significantly higher RPE for the temperature inside the respirator was reported.
The results of the second experiment showed that the effects of RT on working and work pulse were not significant. The PIP, PEP and TIR for SNV were significantly higher than those for SWV. Therefore the SWV was recommended. The effects of TK on working pulse, work pulse, PIP, PEP and RF were significant. The working and work pulse were 3-4 beats/min higher for the task with speaking than task without speaking. The effects of WL on RPE were significant. The RPE score for SNV was significantly higher than that of SWV which could be attributed to the RPE for the temperature inside the respirator. The RPEs for the task with speaking were all significantly higher than task without speaking. The results of RPE were consistent with the measured physiological work load indicators. |
