最小死腔之客製化呼吸防護具研發

Development of Customized Respirators with Minimal Dead Space

劉俊廷(Chun-Ting Liu)

指導教授 ： 陳志傑

國立臺灣大學/公共衛生學院/環境與職業健康科學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202104232

摘要

客製化呼吸防護具可以提供比制式化面罩更好的密合度。客製化面罩的設計流程可分為3D掃描頭模、建立3D面罩模型、3D列印出面罩此三個部分。此外，客製化面罩還可以控制面罩的死腔體積。本研究之目的為建立一個設計客製化面罩的標準流程，同時在設計過程中將面罩死腔最小化，並且瞭解佩戴最小死腔面罩的可接受程度，以及探討面罩死腔最小化對於呼吸生理反應造成的影響。
本研究招募十一名受試者，使用EinScan 3D掃描儀(Shining 3D, Hangzhou, China)取得受試者頭部3D資料，使用鼻樑長度、鼻尖到嘴唇長度、下臉長度、鼻寬度與嘴唇寬度，共五個臉部特徵長度來設計客製化面罩。同時使用1.1、1.2、1.3三個嘴唇寬度的倍數來決定三種不同的左右吸氣閥距離，並結合三種不同呼氣閥底部連接方式(與呼氣閥同高、低5 mm、低10 mm)，來調整面罩死腔體積大小，設計出九款不同大小的最小死腔客製化面罩，接著以3D列印機(Apollo 2.0, Prolink)製作出面罩。將面罩給受試者佩戴後，以問卷調查佩戴體驗。呼吸生理反應的部分，由一名受試者佩戴死腔分別為38, 132, 330 mL的三款面罩，進行運動心肺功能測試(CPX testing)，在運動負荷0到100 W的狀況下，測量佩戴不同面罩運動時，潮氣容積、呼吸頻率、每分鐘通氣量、心率、吸入二氧化碳濃度與潮氣末二氧化碳分壓的變化。
研究結果顯示可以最小化面罩死腔，又不會使呼吸阻抗超過NIOSH標準的最佳閥直徑為25 mm。本研究設計最小死腔客製化面罩，體積約為30 – 50 mL，與市售面罩相比，可降低70 %以上的面罩死腔。根據問卷調查結果，受試者大多都認為最小死腔客製化面罩的佩戴體驗可以接受，且得分最高的面罩之佩戴體驗已經接近市售面罩。運動心肺功能測試方面，結果顯示與市售半面罩相比，佩戴最小死腔面罩，可以降低吸入二氧化碳的濃度(FICO2)達1 %以上，且在相同的運動負荷下，潮氣容積可以降低至少20 %。在運動負荷為100 W時，38與132 mL面罩的每分鐘通氣量比330 mL面罩低約20 %。
總結來說，使用鼻樑長度、鼻尖到嘴唇長度、下臉長度、鼻寬度與嘴唇寬度足以建立一個標準化的最小死腔客製化面罩設計流程。本研究設計之面罩可降低70 %以上的死腔，且大多數的使用者都認為佩戴體驗可以接受。在將面罩死腔最小化之後，能降低面罩內二氧化碳濃度、潮氣容積以及每分鐘通氣量，減輕呼吸的負擔。

關鍵字

客製化 ； 呼吸防護 ； 3D掃描 ； 3D列印 ； 死腔 ； 面罩 ； 口罩

並列摘要

Customized respirators have shown to provide the better protection than the standard-sized commercial respirators. The production processes of customized respirators can be divided into three parts: scanning 3D headform, modeling the respirator body, and 3D printing the respirator. Also, customized respirators can control the respirator dead space. The main objectives are, first, to standardize the design process of customized respirators and to minimize the mask's dead space in the process, second, to understand the acceptance of customized respirators with minimal dead space, third, to evaluate the physiological effects of minimized respirator dead space.
Eleven volunteers are recruited in the present study for the headform measurements using 3D scanning techniques. The five face dimensions, including nasal bridge height, nasal tip to lip length, lower face length, nasal width and lip width, were used to design the customized respirators. Three multiples of lip width (1.1, 1.2, and 1.3) defined the three different distances between right and left inhalation valve. Three different types of connections between the exhalation valve and the mask (same height as the exhalation valve, 5 mm lower, and 10 mm lower) gradually increase volume and comfort. Therefore, nine facepieces with different sizes were made for the volunteers to wear by combining the distances from right to left inhalation valve and the types of connections. The volunteers completed a questionnaire after wearing each mask. The physiological effects of minimal dead space were evaluated by a cardiopulmonary exercise (CPX) testing to measure tidal volume, breathing frequency, minute ventilation, heart rate, concentration of inhaled carbon dioxide (FICO2) and pressure of end-tidal carbon dioxide (PETCO2). One volunteer wore three customized masks with different dead space (38, 132, and 330 mL) then rode a bicycle working from 0 to 100 Watt.
The results show that the air resistance would exceed the NIOSH standard when the valve diameter was less than 25 mm. However, the larger valve would increase dead space. The best inhalation and exhalation valves diameter were 25 mm. The typical minimal dead space was around 30 – 50 mL, 70% smaller than the dead space of most commercial respirators. Among the minimal dead space facepieces from 1st to 9th, from the smallest to the largest, the wearing experience of the 9th facepiece was almost equal to the commercial facepiece. Compared with the commercial half-mask, wearing a minimal dead space mask could reduce FICO2 by more than 1%. Moreover, the tidal volume would decrease 20% at the same workload. The small and medium (38 and 132 mL) masks had 20% less minute ventilation than the large (330 mL) mask at 100 W workload.
In conclusions, using nasal bridge height, nasal tip to lip length, lower face length, nasal width, and lip width are sufficient to establish a standard design rule for the customized respirator with minimal dead space. The dead space of the masks design in the present study are 70% smaller than most of the commercial respirators. Most of the volunteers feel acceptable when wearing the customized respirator with minimal dead space. Minimization of the respirator dead space decrease FICO2, tidal volume and minute ventilation, therefore, reducing the breathing loading.

並列關鍵字

customized respirators ； 3D scanning ； 3D printing ； dead space ； mask

參考文獻

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