# Challenging COVID-19 with Creativity: Supporting Design Space Exploration for Emergency Vertilators
## 1 Introduction  
### The COVID-19 Pandemic and the Role of Low-Cost Vertilators  
The Coronavirus disease, officially acknowledged as COVID-19 by the World Health Organization (WHO) [1], suddenly led the world to face a critical emergency, with a lot of patients with severe respiratory problems. After the cases in China, Italy was the first accidental country to report a very high number of infections, with a very high concentration in the Lombardy region. The rapid and vast spreading of the infection is sadly acknowledged by everyone, therefore for the scope of this paper it is sufficient to report that currently, more than ten million cases and nearly 500 thousand deaths have been registered throughout the world (data from the WHO website [2]). It has emerged that for supporting the respiration of patients affected by the most severe symptoms, the use of automatic ventilators has been one of the crucial parameters for reducing death cases [3, 4]. Unfortunately, and especially in Italy, it rapidly became evident that the available ventilators were outnumbered by the number of patients. Many solutions have been conceived to better exploit the available devices. For example, some studies have focused on the possibility of using the same ventilator for multiple patients (e.g., [5, 6, 7]), while others have concentrated on the optimization of ventilator triage procedures (e.g., [8, 9]) or the possibility to share ventilators among hospitals [10]. A comprehensive review ofthe different studies concerning ventilators falls out of the scope of this work, where the attention is focused on a particular phenomenon. More specifically, many designers, research groups, or simply enthusiasts have started to provide many open-source contributions of ideas about how to design and manufacture low-cost ventilators or parts of them (e.g., [11; 12; 13]), with the aim of supporting the supply of these devices. However, notwithstanding the different attempts to solve the problem, the need for ventilators is still crucial [14]. Therefore, this design-related way to fight the pandemic can also be very helpful because it strives to produce low-cost ventilators that can be easily afforded by hospitals (especially in developing countries, e.g., in Africa or South America). The ventilator design task is quite complex, and, even if focusing on low-cost devices, it is possible to find many problems that need to be faced. Indeed, ventilators can be both invasive and non-invasive [15], and many functionalities need to be carefully considered, from the filtration of the exhaled air to the different controls and requirements that should be satisfied [16]. However, among the different open-source contributions that can be currently found (a list has been recently made [17]), many of them exploit the advantages provided by the adoption of the standard auxiliary manual breathing unit, or simply \"AMBU bag\" (see Figure 1), which is also known as a bag valve mask (BVM) unit or \"manual resuscitator\". Notably, the considered type of non-invasive ventilator works by automatically compressing the bag with a mechanical system, hence it overcomes the need to employ a human resource. In cases of emergency, AMBU-based devices can be used to take care of patients when other ventilation systems are not available. With the aim of providing emergency and non-invasive ventilation systems, AMBU bags offer the opportunity to use parts already available, which are certified according to the standards in force, thus allowing the design efforts to be limited to the mechanism that automatically compresses the bag (and related controls). Moreover, this type of ventilator can be used for both endotracheal tube and non-invasive mechanical ventilation through a mask (similarly to what happens for continuous positive airway pressure (CPAP) ventilation) [18]. It is important to state from the outset that the selection of the most suitable ventilation system is the total responsibility of the medical staff.