Meeting Your Electrical Safety and Quality Requirements

Compliance with 60601-1 is not just about electrical safety; it is also about addressing mechanical, structural and environmental factors, and following a process to address usability, risk management and software development.

I recently returned from Boston BIOMEDevice, where I gave a Learning Lab presentation on electro-medical device basic safety and achieving compliance with IEC 60601. For those who couldn’t attend, here are highlights from Day 1 of the Learning Lab event. 

Human factors and usability:

This session was packed with useful information on usability engineering, ideal for those from an engineering background new to medical device development. Remember, FDA no longer considers “user error” as an acceptable root cause. Every effort must be made to identify workflow, frequently used function, foreseeable misuse and routine violations (where the operator knows what they are doing is wrong, but does it anyway), and address or mitigate to prevent unacceptable risk of harm to the patient or operator. 

In particular, the goals of the session were to understand:

  • The practical application and documentation of two essential Human Factors Engineering activities: task analysis and use error analysis; 
  • The inputs to a task analysis and a use error analysis; 
  • The influence of the task analysis and use error analysis on subsequent Human Factors Engineering activities; 
  • The relationship between Human Factors Engineering and other engineering activities; and 
  • The value of Human Factors Engineering to the design process and the regulatory compliance process.  

3-D printing

It seems 3-D printing is everywhere now – from hobbyist and maker conventions to paper and staples office suppliers, so why not medical devices? We noted recently that surgeons are already using CT and MRI scan data to build 3-D printed hearts to understand and practice on congenital abnormalities in children. Four presentations extended this scope of 3-D printing to building non-functional and functional prototypes for evaluation.

In addition, substantial progress is being made in the area of high temperature polymer printing, and the grand prize: printed electronics with printed substrates and polymer structural housing. 

Medical device sensors

A discussion of the innovation being made in implantable sensors. The diabetes pandemic has prompted lots of innovative work in the area of artificial pancreas, which require an accurate, precise and reliable/long lived glucose sensor. Additionally, the area of MEMs sensors is developing tiny sensors for hitherto unimagined areas. 

Battery and power management

Greatbatch, well known in the medical space for developing long life, primary cells for implantable devices, discussed their advances in long-life (10 years without appreciable self-discharge), novel electrode primary cells which are, among other things, MRI compatible, and their efforts in developing primary cells that can be sterilized at 134C. Their new development in rechargeable lithium cells are designed for a 3,000 lifetime. The trade-off being an overall reduced capacity, unlike consumer/laptop cells which are designed for maximum capacity but have a useful life of only 500 cycles. 

Greatbatch are also developing lithium cells which can be depleted to zero volts, without damage. Regular rechargeable lithium cells suffer corrosion of the internal terminals (anode/cathode), and cannot be depleted to zero volts and maintain capacity – hence the requirement for Power Control Modules (PCM) in lithium cell packs. Another presentation in this lab discussed the innovation being developed in the area of body power generation – either body movement or temperature differences being used to power implantable or body worn products. 

Meeting your electrical safety and quality requirements

The essence of my presentation was that 60601-1 compliance is not just about electrical safety, even though many people in the trade often still think of it that way. To achieve 60601-1 compliance, the developer must address mechanical, structural and environmental factors. The standard also requires following a process to address usability, risk management and software development – the observant of you will have noticed this is pretty much the entire Design History File (DHF).

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