Point-of-care 3D printing during the COVID-19 pandemic. What role does the manufacturing university hospital play?

Background Point-of-care (POC) manufacturing and distributed production represent a paradigm shift in the health system that is becoming critical during the COVID-19 pandemic. University hospitals are also taking on the role of manufacturers of custom-made solutions thanks to 3D printing technology. Case Description We present a monocentric observational study regarding the distributed manufacture of three groups of products during the period of the COVID-19 pandemic from 14 March to 10 May 2020: personal protective equipment, ventilatory support, and diagnostic and consumable products. and has enabled the of a of manufactured using The was and ear and The were in 57.3% acted delivery in a The production model is fast response to stock needs, being able to adapt almost in real time.


Background
The exponential demand for technical and human resources caused by the COVID-19 pandemic has challenged public health, healthcare organization and hospital care, bringing health systems in many countries to the brink of collapse, with the added di culty of coping with chronic shortages of personal protective equipment (PPE) and other essential medical supplies [1]. These problems, accentuated both by relocation and by the reduction in business activity due to a lack of supplies from abroad, have shown that it is necessary to have certain manufacturing capacities for the production and equitable supply of essential products, which are crucial for saving lives, as well as for curbing the socio-economic impact [2].3D printing is a technology that can lead this change in the manufacturing paradigm. It allows the design to be made anywhere in the world because the product as such moves in a digital format to any place, just by printing it with a 3D printer [3]. In this context of distributed manufacturing, the fact that products are obtained from the same machine at a xed and predictable cost makes it possible to print at a location close to the end user, ensuring that they arrive in the shortest possible time [4]. The expiration of patents related to different 3D printing technologies such as FDM (Fused Deposition Modeling), the existence of new digital and social platforms, the possibility of collaborative projects ("crowdfunding"), and socio-cultural movements such as the Maker movement [5], have allowed people not only to consume, but also to make and share. Access to this technology during the pandemic has made it easier for professionals and patients, with the aim of seeking to improve people's health, to react to the shortage of equipment by promoting new production models that can quickly respond to a situation of complete uncertainty in health action with regard to such basic issues as transmission, lethality and ethical questions regarding the prioritisation of resources.
In these new production models, manufacturing university hospitals, understood as the hospital acting as a manufacturing centre using in-house 3D printing technology and distributed production, are part of hubs that allow them to reconcile in-house manufacturing and outsourcing services, strengthening collaborative work and ensuring that this type of manufacturing becomes the standard of care [6-9] and being able to e ciently adjust their resources, objectively identifying their limitations and creating external partnerships. New production models such as point-of-care manufacturing are contemplated, and this makes it possible to respond to needs for space or expensive facilities, to bring together the technical competence pro le in industrial aspects, or to keep its portfolio of services up to date without depending on the obsolescence of machines and manufacturing materials, which is very rapid for this type of technology. [6] The aim of the study is to identify the role of 3D printing technology in a manufacturing university hospital during the COVID-19 pandemic.

Case Description
This is an observational, descriptive, monocentric study that includes all the projects developed from the

Results
Networking during this period has enabled the delivery of a total of 17,276 units of products manufactured using 3D printing technology. (Fig. 1) All models manufactured had an end-use. Requirements were communicated to our laboratory on a daily basis and printed in-house or by external equipment according to availability and volume required. The models had a very intuitive use in most cases, or very technical use in some cases, such as adapters for ventilation systems.
End products delivered can be divided into three main groups: 1. Protection and prevention systems (Fig. 2). This group includes the manufacture of face shields, 3D printed photophore accessories, ear savers, hands-free door openers, or prototypes of masks.
2. Products for Ventilatory Support Therapies (Fig. 3). The peak of hospital admissions due to the pandemic has caused a great demand for ventilation machines, with the consequent transitory lack, so we decided to modify non-sanitary material and sanitary material approved for other uses. This has allowed us to perform non-invasive treatment in those patients who needed respiratory support but not without su cient stock of approved devices. In our center we have used the Easybreath® (Decathlon, France) diving mask system modi ed as a CPAP system (EASY-CPAP), having been necessary the acquisition of masks [10-13], the production of connector parts or supports, and the optimization of the design of other parts adding modi cations to adapt it to the existing material in our center. Among the products manufactured, we have included connection parts for the masks and other parts for the ventilation systems such as straight connectors, connectors with side port for oxygen therapy or adapters for positive protection systems.
3. Diagnostic products and consumables (Fig. 4). This group includes the manufacture of swabs of different designs to perform the nasopharyngeal smears necessary for the diagnosis of SARS-CoV-2 infection by PCR test. The geometry of the head, the length of the handle and the position of the stigma are con gurable elements that have been adapted to the different formats of the container tubes available in our Centre.
Considered as a class IIa medical device and manufactured by means of stereolithography technology (SLA) with biocompatible light-curing resin, it is presented in sterile packaging in bags of 10 units and in unitary peel-packs adjusted to local needs.
In addition, donations of other products such as masks or 3D printing material for FDM technology have been received.
The products were mainly manufactured by individuals (57.3%), universities (7.6%) or associations (2.8%).Manufacturing companies have made 28% of the products, and the rest (4.3%) have been achieved through in-house manufacturing, in this last case being mostly prototypes and product validations.
The products have been donations in 78.2% of the cases. However, if a greater quantity and optimisation of the production times of a product has been required due to care needs, the acquisition has been made through public purchase. This is the case of face shields or some of the products for ventilatory support, with the purchase of 49% of the 3d printed face shields, 63% of the Charlotte adapters, 48% of the side port connectors and 8% of the Dave adapters.
The delivery date of the products started on March 25th and has been extended until the last day of the study period. Since the beginning of the period, production has been adapted to the demand made by the services in charge of both the availability, coordination and logistics of the personal protective equipment and the care needs of the clinical services involved in the ventilatory support therapies. Thus, during the rst week 83.7% of the face shields had already been delivered. However, the demand for other products has been later, such as the connectors for ventilatory support delivered from 31st March, or the ear savers whose rst delivery was made on 14th April.
The destination of the products delivered was the Centre itself in 90.9% of the cases, although the production capacity, together with the demand caused by the global shortage, made it possible to deliver products to other Centres (Table 1). Discussion And Evaluation: The integration of 3D printing technology in the healthcare process allows for the monitoring of the end-to-end process, from the design and validation for clinical use of different products to the optimized production of these products adapted to the healthcare need, which is of great importance in health systems during periods of sanitary crisis such as the COVID-19 pandemic, when the shortage of healthcare resources at a global level makes universal availability and coverage impossible.
The manufacturing university hospital is not born as a competition of the factories or the traditional medical industry, but it generates value in personalized medicine by gathering the professional team and the necessary resources to be able to treat by means of a personalized medical product with the maximum guarantees of quality and commitment to the patients, generating knowledge based on each individual experience, and thus allowing a qualitative leap in exponential patient-centered medicine.
Hospital General Universitario Gregorio Marañón is a pioneer in the transversal implementation of 3D printing at a hospital level, incorporating an advanced planning and POC manufacturing unit integrated as an in-house 3D printing laboratory in the care ow of more than 20 medical-surgical specialties. Our 3D printing laboratory was founded in 2015, initially manufacturing biomodels with FDM technology, and later surgical guides in resin using  (Table 2). The disinterested offer of the different actors to participate in this type of production has made it possible both to cover the intrahospital demand and to collaborate with other centres, even at times when the need for speci c products has required an increase in production.
In our study, it is interesting to note that the rst products are delivered 11 days after the start of the alarm period.
This is justi able because in the rst days of the study period, and in the face of a minor casuistry, the demand for products was also lower. In those rst days, the activity as a manufacturing university hospital consisted of designing and validating prototypes as well as identifying collaborators for the constitution of a distributed production network (Fig. 5), so that incidents in terms of need and/or supply could be minimized with the most agile response possible . Thus, after 7 days, the rst face shields units were manufactured and delivered under the coordination of the Services responsible for occupational risk prevention. An internal validation of the design was carried out, and after assessing the bene t-risk in the areas with more limited resources, the distribution was staggered. Something similar has occurred in the manufacture of parts for ventilatory support: when the lack and di culty of supply from the different Clinical Services is identi ed, it is reported to the UPAM3D from where action is coordinated not only to respond to the high demand, but also for rapid prototyping or design improvements.
The production offer of a large number of participating actors has facilitated the maintenance of the rhythm of production and collaborative work with other Centres, also allowing a staggered delivery and adjusted in real time to the demand.
In the period of study of our study we had to apply emergency solutions, where the vocation and personal effort were essential. Given the exorbitant prices of products with very low stock at that time, the general feeling was one of great speed of response and access to a large number of products at a very low cost, although a costeconomic analysis is not available because it was an exceptional situation where any comparative reference price had not been extrapolated.
Although there are multiple bene ts related to POC manufacturing, and even being very signi cant the contribution in terms of internal knowledge generation, customization, local quality control and cost reduction; we undoubtedly want to highlight the response times as the main advantage over traditional manufacturing and distribution. During this rst wave of the pandemic, the pace of manufacturing and the minimum delay with the commissioning, the scalability of production and the capacity of adaptation to the exponential increase experienced, have been key factors in placing this health product manufacturing paradigm in a preferential position within the health system.

Conclusion
In spite of the limitation of being a descriptive study conditioned by the activity of a third-level university hospital with a very high casuistry of patients affected by COVID-19, which has forced a restructuring of the Centre at all levels [16], the results obtained re ect that the role of the manufacturing hospital allows the reconciliation of inhouse and distributed manufacturing with traditional production, providing custom-made adaptation of the speci cations, as well as maximum e ciency in the working and availability of resources, which is of special importance at critical times for health systems such as the current COVID-19 pandemic.  Images from the STL les and pictures of protection products. Images from the STL les and pictures of ventilation products.

Figure 4
Images from the STL les and pictures of 3D printed swabs.

Figure 5
Example of distributed production. Hospital General Universitario Gregorio Marañón.