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First, it is important to consider what level of protection is required. For example, there are many types of masks with different uses and regulatory standards [ 48-51 ]. Some simpler masks, often called surgical masks, are used by infected people to reduce the spread of infection by catching large droplets, such as after coughing and sneezing. Such masks are easy to make at home (e.g. [ 52 ], Table 1A), but they are generally not considered an effective way to prevent infection [ 21 , 22 , 35 ]. Nonetheless, it has been suggested that they can reduce the spread of viral particles from infected individuals [53]. This was elaborated on in a recent influential paper [ 54 ], but this study did not study SARS-CoV-2, nor possible transmission by asymptomatic carriers (see also [ 55 ]). Another study of four COVID-19 patients found that medical masks were ineffective in preventing the spread of SARS-CoV2 [ 56 ]. Whether medical masks should be recommended for public use, and in what specific circumstances, remains a matter of ongoing debate. At the time of writing, the World Health Organization (WHO) recommends:<\/p>\n\n\n\n
If you are healthy, you only need to wear a mask when caring for someone with suspected 2019-nCoV infection. If you cough or sneeze, wear a mask. For an up-to-date summary of the effects and uses of various masks, see their official recommendations [ 57 ]. Of note, the US Centers for Disease Control (CDC) currently recommends wearing masks in public settings where other social distancing measures are difficult to maintain, especially in areas with significant community transmission [ 58 ]. Additionally, other countries are likely to follow suit, especially as the world reopens.<\/p>\n\n\n\n
Unlike medical masks, so-called N95 filtering facepiece respirators (FFR) are designed to provide a high level of protection to the wearer, such as would be used by medical staff when caring for infected patients, for example. Unlike medical masks, these masks are designed to seal to prevent air from escaping through the gap between the skin and the mask, and contain specialized filters within the mask that act as a physical barrier to block particles as small as 0.3 microns. This is still larger than an actual virus (about 0.12 microns) [ 59 ], but much smaller than most droplets expelled when sneezing or coughing. The performance standards for such masks are strictly regulated [ 48 - 51 ] and any DIY approach to replicating these masks must carefully refer to these regulations, which may also vary from location to location. Therefore, controlled testing of existing and upcoming N95-type FFR prototypes is critical. Furthermore, if worn incorrectly, they may end up being of little use as medical masks [ 57 ]. For eye protection, N95s can be used in conjunction with tight-fitting goggles or a face shield.<\/p>\n\n\n\n
Currently, there are many different types of mask DIY designs on the market, ranging from simple video tutorials based on napkins, cloth, or bra cups (Table 1A) [60-62], to 3D printing options [63], to peer-reviewed scientific studies Designs developed and\/or tested [25, 26] (Fig. 1). Some designs are very effective [ 25 ], but to our knowledge, none have fully met regulatory standards to date. However, with designs currently being released on a daily basis, that may soon change. Table 1B summarizes the subset of DIY N95 projects available at the time of this writing.<\/p>\n\n\n\n
Alternatively, medical personnel can use splash-resistant surgical masks (IIR, resistant to 160 mmHg) and face shields [ 42 ]. The latter combination may be easier to meet regulatory standards than N95 masks [ 56 ], in part because they do not need to fit tightly against the skin. An online search quickly turns up several designs of masks (and IIR [44]) with varying levels of associated testing [64,65] (Table 1C, Figure 1E). For example, 3D Crowd is a UK-based citizen network that is mobilizing volunteers to produce DIY face coverings to deliver to hospitals and healthcare facilities [ 66 ]. Through \u201cThe Big Print,\u201d they have collected requests for 370,000 units. More than 5,500 volunteers are currently producing 80,000 of them. Another approach is based on existing full-face snorkel masks [ 67 ], which can be effectively used as a combination mask and goggles. Efforts such as this, including their important experimental validation, can be easily scaled up with minimal investment. They may also be easier to disinfect for reuse than masks [ 68 , 69 ].<\/p>\n\n\n\n
In addition, more specialized personal protective equipment is also actively being developed. This includes DIY testing chambers for diagnostics (requiring virus inactivation in a biosafety level 2 facility BSL2 prior to testing, see below) and DIY aerosol cartridges, for example for intubating patients (Figure 1F, Table 1D) . As with all medical devices, these require regulatory approval [ 48 \u2013 51 ].<\/p>\n\n\n\n
The selection of construction materials for PPE should take careful consideration of the construction materials. For example, it has been suggested that the porosity of 3D printing materials may make them a dangerous choice for making masks, as they may allow viral droplets to persist for extended periods of time [ 68 ]. Gaps that may exist in the material itself (e.g. due to bubbling or imperfect delamination during the printing process) further add to the scope for concern. At the time of writing, we are not aware of the available data on the above points. Likewise, when laser cutting parts, the need to use acrylics should be carefully weighed against the need to sterilize them with alcohol or peroxide, which can react with acrylics. If available, and if a laser cutter on hand can handle it (many cannot), polycarbonate or polyethylene terephthalate glycol (PETG) sheets may be a safer choice. DIY PPE disinfection guidance can be found here [ 70 ]. Throughout the process, it is also important to consider possible changes in quality due to the building process itself.<\/p>\n\n\n\n
FOSH Ventilator A ventilator is a medical device that supports or takes over a patient's breathing by delivering air or other mixed gases. Patients who are able to breathe on their own are usually treated with constant airflow from an intubation or positive pressure mask (PPM). In more severe cases, the patient may need to be intubated (a tube inserted into the patient's airway). In this case, some modern ventilators can synchronize the release of gas with any remaining attempts at natural breathing. In other cases, the ventilator can take over completely (often in conjunction with patient sedation). At the end of treatment, the patient must be carefully weaned from the ventilator. In general, using a ventilator carries risks of infection, including pneumonia, lung damage, and oxygen toxicity. The latter two may sometimes be related to improper use of equipment (e.g. too high air pressure and\/or too high oxygen concentration).<\/p>\n\n\n\n
From a technical perspective, a ventilator can be as simple as a manually operated compression bag (Bag Mask - BVM) or as complex as a fully computerized machine that regulates gas pressure, humidity, relative gas concentration, and circulation rate while performing real-time Measurements are taken to monitor patient condition. Some more modern systems add to this complexity, making them more suitable for long-term use because they better simulate physiological conditions and can be adjusted to the patient's specific needs. The National Institutes of Health (NIH) provides an overview of ventilators and their use [ 71 ], including various interface types, ventilator features, and other details not covered in this article. The UK has also recently published its own specifications for hospital ventilators [ 72 ].<\/p>\n\n\n\n
The use of non-invasive respiratory systems for COVID-19 patients is currently controversial in hospitals because such systems may generate aerosols that increase the risk of infecting others [ 73 ]. Nonetheless, some believe that non-invasive respiratory systems can be useful in certain circumstances [ 74 ], and the use of such systems may increase as conditions worsen. However, only invasive respiratory systems can completely take over breathing when necessary.<\/p>\n\n\n\n
Today, ventilators are already limited for patient care, and this situation may become more severe in the near future [75\u201377]. Current efforts to resolve this impasse include halting elective surgeries to free up existing systems [78], reactivating deprecated models in warehouses, and calling on industry to increase production [1, 79]. At the same time, diverse groups around the world are convening their communities to design FOSH solutions to help increase ventilator availability (Figure 2, Table 2). Some examples include the development of complete and self-contained systems [ 80 , 81 ], automation of manual ventilators [ 31 , 33 , 37 ], and repair of existing but decommissioned equipment, such as using 3D printed replacement parts [ 82 , 83 ]. Many projects are actively looking for collaborators with diverse backgrounds. FOSH ventilators for invasive use require the implementation of sensor-based feedback systems to measure pressure, carbon dioxide and oxygen levels, tidal volume and dead space volume, and air humidity. These are necessary measurements to know if the machine is performing as expected and not causing further harm to the patient.<\/p>\n","protected":false},"excerpt":{"rendered":"
As COVID-19 spreads rapidly, global health systems are […]<\/p>\n","protected":false},"author":5,"featured_media":3112,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[],"tags":[],"class_list":["post-3111","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry"],"yoast_head":"\n