Due to the COVID-19 pandemic situation and a number of hospitals, there is a shortage of personal protective equipment. The 3D printing community, trying to help get involved in 3D printing of face shields, which – according to those provided by medical staff – enable their role. The matter of 3D printing looks different – more complicated equipment, such as N95 type protective masks, medical equipment components or ventilators. Does it make sense using 3D printing to manufacture this type of equipment like ventilator yourself? And is it safe?

In the face of this situation, the MHRA, i.e. the British Office for Registration of Medicinal Products and Medical Devices has issued a document that must take into account the clinical recommendations that must be met by a ventilator made by 3D printing to be able to use a United Kingdom (UK) used during the COVID-19 pandemic. A comprehensive document is described when a ventilator can bring therapeutic benefit and when it poses a threat to the patient’s life and health.

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MHRA focuses on devices that can be used in short periods of patient stabilization for several hours – in extreme cases, as maintaining the necessary minimum, this can be extended to one day. In the document, each of the aspects considered has the following levels of requirements:

  • MUST – a minimal, clinically acceptable feature of the device.
  • SHOULD – highly desirable features. If omitting them allows faster production of the device, consider this option.
  • MAY – features with a low priority of importance, often found in ventilators. If their implementation causes delays in production, they should be omitted.

The document considers the following aspects:

  • Ventilation – information on ventilation modes and types, as well as precisely defined values ​​describing plateau pressure or peak pressure
  • Gas and power supply – the issue of gas supply to the device and the patient is explained in detail, with reference to specific standards and directives. Power issues are also raised
  • Infection control – the whole attachment (Annex A) is devoted to this important issue, indicating how important it is to be able to clean and disinfect parts of the ventilator,
  • Monitoring and alerts – the document states that “the key is to include the appropriate alerts, but not too many of them, so that the operator is clear, immediately readable and unambiguously interpreted signals.”
  • Biosecurity – particularly relevant information on materials and production methods, based on the standard is ISO 18562-1: 2017 – Assessment of the biocompatibility of breathing gas supply systems in medical applications).
  • Software security – security is a critical issue in the problem under consideration – you should be aware that “in a high-risk device such as a ventilator, it can almost certainly cause serious injury or death if appropriate security or control measures are not applied.”
  • Additional issues – an important point where the issues were highlighted would seem obvious, but important for the proper functioning of the device, such as the need for reliable operation of the device or the possibility of easy operation by medical personnel.
  • Testing – for the device to be considered as functioning correctly and safely it must undergo the validation procedure detailed in the document attachment (Annex B).

Amateur ventilator and 3D printing

In all of the above points, special emphasis is placed on patient safety and minimizing the possible risk of infection of the patient’s respiratory tract. Although the global situation is a crisis, this does not mean that all safety standards cease to apply – the viewer gathered in the standards and directives should be used, and the guidelines set out therein should be followed as much as possible. It takes huge responsibility to make a ventilator using 3D printing technique.

The document also contains detailed procedures for testing ventilator made with use of 3D printing technology, which strictly specify parameters regarding oxygen consumption or the value of the transitional input flow rate. When proposing your own device, you should be aware that the creator is obliged to know the answers to more or less complicated questions (e.g. How much oxygen does the ventilator use , Does it have an emergency battery supply?, Is it equipped with the necessary alarm informing about flow problems gas?).

The fact that MHRA does not expect the device to be CE certified does not mean that the devices do not have to comply with restrictive guidelines. On the contrary – for the safety of patients, fast-build ventilators using 3D printing technology must meet a number of requirements (defined in detail) to help and not to save lives.

It is worth emphasizing that the intensive care system in which ventilators are used is the whole process in which they cannot be safely used on any patient without the participation of trained personnel, additional equipment or medicines. You should be fully aware of this, both by constructing and sharing your own ventilator designs, and by 3D printing it using publicly available files.
Magdalena Przychodniak
Editor-in-Chief of the 3D Printing Center. A biomedical engineer following the latest reports on bioprinting and 3D printing in modern medicine.

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