防疫型氧氣面罩研發

Abstract

氧氣面罩做為提高病人吸入氧氣分率的裝置，常用來治療有低血氧症狀的病人。然而，在氧氣面罩使用期間病人無法配戴呼吸防護具，若病人患有呼吸道傳染性疾病，會使醫護人員暴露於染病的風險之中。在提高吸入氧氣分率方面，氧氣面罩上排氣孔設計位置和面罩不密合處都有可能使氧氣面罩的使用無法達到預期的吸入氧氣分率。因此，本研究旨在設計具有防疫效果並且和市售氧氣面罩相比能提供有較高的吸入氧氣分率的防疫型氧氣面罩。 本研究利用繪圖軟體設計防疫型氧氣面罩，面罩分為內層與外層，再使用3D列印技術生成並測試，總共分成四個實驗，分別為面罩密合度測試、面罩捕集效率測試、氧氣分率測試以及面罩內負壓值測試。面罩密合度測試可以探討洩漏處、洩漏面積與密合度的關係，並且可以將密合程度定量；面罩捕集效率測試可以了解不同面罩設計對於病人吐出微粒的捕集效果；氧氣分率測試可以了解使用防疫型氧氣面罩期間不同抽氣流率對於氧氣分率的影響，也可以知道何種面罩設計能有較好的氧氣分率；為了不讓抽氣期間產生過大的負壓造成病人呼吸負擔，同時也會量測面罩內的負壓值。最後將面罩捕集效率測試、氧氣分率測試以及面罩內負壓值測試3項數據進行綜合評估，找出捕集效率最好、氧氣分率最高和負壓值最低的設計。 研究結果顯示洩漏面積和密合度呈反比關係，面罩內外層間距越小(1 mm)、內外層高度差越大(10 mm)會有較好的面罩的捕集效率，透過調整面罩的抽氣範圍與在內層增加分隔呼出氣體與輸入氧氣氣流的隔板可以使氧氣分率提升，此設計也比市售氧氣面罩的氧氣分率還高；提高面罩密合度雖然也會有較好的捕集效率，但同時也會增加面罩內的負壓值，因此密合度值為10是較理想的設計；面罩的洩漏位置和面積也會影響捕集效率和氧氣分率，其中鼻樑處洩漏會降低氧氣分率，下巴處洩漏會降低捕集效率。 本研究透過實驗證實防疫型氧氣面罩可以兼具防疫和提高氧氣分率的功能，透過調整密合度、面罩內外層間距與高度差、面罩抽氣範圍、內層隔板找出較理想的面罩設計，在洩漏處部分，可以在鼻樑處和下巴處增加密合度提高捕集效率和氧氣分率。然而在抽取有效抽氣流率的情況下，目前設計還須提高氧氣流率才能到達市售氧氣面罩(未抽氣)的氧氣分率。

An oxygen mask is a device that increases the rate of oxygen inhaled by a patient and is often used to treat patients with hypoxemia. However, using oxygen masks on patients with infectious respiratory diseases can expose healthcare workers to illness. In terms of improving the inhaled oxygen fraction, the design position of the vent holes on the oxygen mask and the poor fit of the mask may make the use of the oxygen mask unable to achieve the expected inhaled oxygen fraction. Therefore, this study aimed to design a preventing infection oxygen mask that could prevent infection and could provide a higher fraction of inhaled oxygen compared to commercially available oxygen masks. This research uses software to design a preventing infection oxygen mask. The mask is divided into an inner layer and an outer layer and then uses 3D printing technology to generate. It is divided into four experiments. The mask fitting test can explore the relationship between the leak, the leakage area, and the fit factor. It also can quantify the fit factor. The mask capture efficiency test can realize the mask’s capture effect on the particles spits out by the patient. The oxygen fraction test can understand the impact of airflow rate on the oxygen fraction. It can also be known which mask design can have a better oxygen fraction. We also measure the negative pressure value in the mask. Finally, the results of the mask collection efficiency test, the oxygen fraction test, and the negative pressure value test are comprehensively evaluated to find out the design with the best capture efficiency, the highest oxygen fraction, and the lowest negative pressure value. The research results show that the leakage area and the fit factor are inversely proportional. The smaller the distance between the inner and outer layers of the mask (1 mm) and the larger the height difference between the inner and outer layers (10 mm), the better the capture efficiency of the mask. The scope and inner layer can increase the oxygen fraction by adding a partition that separates the exhaled gas and the input oxygen flow. This design is also higher than the oxygen fraction of commercially available oxygen masks. However, improving the mask fit factor also has a better capture effect. At the same time, it will increase the negative pressure value in the mask, so a fit factor of about 10 is an ideal design. The leakage position and area of the mask also affect the capture efficiency and oxygen fraction. The leakage at the nose would be reduced oxygen fraction, and chin leaks would reduce capture efficiency. In this study, it was confirmed through experiments that the preventing infection oxygen mask can have both anti-epidemic and oxygen-enhancing functions. By adjusting the fit factor, the distance and height difference between the inner and outer layers of the mask, the air extraction range of the mask, and the inner layer partition, an ideal mask design was found. The fit factor can be increased at the nose and the chin to improve the capture efficiency and oxygen fraction. However, the current design still has to increase the oxygen flow rate to reach the oxygen fraction of a commercially available oxygen mask while sucking an effective extraction flow rate.