IEC 62366:2007, Medical Devices,Usability Engineering Process (UEP), Usability Engineering File(UEF)

1. Medical Devices
More then one third of Medical Device incidents involve usability issues and 44,000
– 98,000 patients killed each year by preventable medical mistakes. Among major
causes of medical mistakes there are: 15-20% mechanical failure and 60-80% human
error. Even when using the lower estimate, deaths in hospitals due to preventable
adverse events exceed the number attributable to the 8th-leading cause of death.
Deaths due to preventable adverse events exceed the deaths attributable to motor
vehicle accidents: 43,458, breast cancer: 42,297 or AIDS: 16,516.
90 Mar-Apr 2010 Medical Equipment & Automation

2. Medical Devices
and more stress on Usability
aspect today. Here we have
tried to have a glance through
new standards that addresses
application of Usability
Engineering to Medical devices.
To address Usability aspect
there is relatively new standards
ISO/IEC 62366 that provides
guidance to Manufacturers and
Designers of Medical Devices.
This standard was included in
Official Journal of the European
Union on November 2008.
Let us first see some terms
Application of Usability and their definitions from
applicable standards:
• USABILITY: characteristic that
Engineering to establishes effectiveness,
Medical Devices efficiency and operator
learnability and satisfaction.
New International Standard • USABILITY ENGINEERING:
application of knowledge
ISO/IEC 62366:Medical Devices about human behavior,
abilities, limitations, and other
characteristics to the design of
tools, machines, equipment,
devices, systems, tasks, jobs,
and environments to achieve
adequate usability.
• VERIFICATION: confirmation
by examination and provision
of objective evidence that
specified requirements have
been fulfilled.
• NORMAL USE: operation,
including routine inspection
and adjustments by any
operator, and stand-by,
according to the instructions
t is very evident from Today’s hospital environment for use.
I available data that launching
products with poor usability
can involve high risk and
expensive redesigns. If usability
aspect is not taken care in initial
is becoming very demanding
and increase use of software in
devices to make it user friendly has
caused increasingly complex user
interfaces that finally becomes
NOTE: Normal use should not
be confused with intended
use. while both include the
concept of use as intended by
the manufacturer, intended use
stages of Design it can result part of Usability problems. In focuses on the medical purpose
in poor customer experience, Medical Devices, stakes are very while normal use incorporates
tremendous customer service high as poor usability can result in not only the medical purpose,
calls / complaints, lost user Lost or impaired Life. To address but maintenance, service,
productivity and lost revenue. this problem there is more transport, etc. as well.
Medical Equipment & Automation Mar-Apr 2010 91

3. Medical Devices
• ABNORMAL USE: intended The file can be part
act or intended omission of of the risk management
an act by the responsible file, or it may be part
organization or operator of of the product design
medical device as a result of file, or it can be an
conduct that is beyond any independent document
reasonable means of risk or set of documents. The
control by the manufacturer. file itself does not need to
contain all of the records
IEC 62366 states that Medical and other documents
Device Manufacturer shall have produced by the Usability
Engineering Process,
Usability This Usability
but it should contain
Engineering Process Engineering
(UEP) that relates to Process UEP references and pointers
Safety of Medical should be able to to the whereabouts of all
Device with which • Assess required documentation.
they can • Mitigate risk The file enables efficient
• Analyze caused by Usability auditing of the design and Use Error Examples from
• Specify problem related to
development process. IEC 62366
• Design Correct use and
• Verify and Use Errors (defined
• Operator confuses two
• Validate as Normal Use “If the usability of user interfaces buttons and presses the
Usability in IEC) was improved, incidents and wrong button.
accidents could be reduced as • Operator misinterprets the
Information derived from UEP could the required time to learn icon and selects the wrong
can be used to identify risks how to use new equipment”. function.
associated with abnormal use • Operator enters incorrect
but doesn’t assess or mitigate Usability testing requires users sequence and fails to initiate
risks associated with abnormal to perform tasks to measure the infusion.
use. It is important to understand performance of a device in terms • Operator fails to detect a
that- of task time, ease of use or amount dangerous increase in heart
• Use error is repetitive and can of errors. Tests can be performed rate because the alarm limit
be predicted. either in a suitably equipped is mistakenly set too high and
• User error is due to usability lab or in the field and can operator is over-reliant on
fundamental errors by either involve a fully functional or alarm system.
humans that has no possibility non-working prototype. • Operator cracks catheter
of prediction. connector when tightening or
Do’s and Don’ts for loosening the connector.
What is Usability Usability Process • A centrifugal pump is cleaned
Engineering Process
The standard describes a Do’s Don’ts
Usability Engineering Process with • Treat use error as a risk to be • “If the operator does that, it is not our
9 stages. We have tried to put it as understood and controlled. responsibility.”
• Identify and understand • Vague description of the fault / use error
below:
foreseeable use error risk. (e.g. ‘operator error’, ‘programming error’,
• Assess the clinical severity of use ‘sample mishandled’)
Engineering File (UEF) errors. • Not documenting a fault/ hazard because
To comply with the standard, • Control or mitigate use error risk the mode of control is assumed effective.
you need to document all aspects in design. • Not documenting a fault/ hazard because:
of the process in a Usability • Validate risk mitigation “no one will ever do that !”
Engineering File. This file provides effectiveness through testing with • Not documenting a fault / hazard because
traceability to demonstrate that users. ‘we would be liable if it happens (and we
• Document risk management don’t have a mode of control for it)’.
you have followed the Usability efforts.
Engineering Process.
92 Mar-Apr 2010 Medical Equipment & Automation

4. Medical Devices
accompanying documents
as a result of user’s failure to
arrange for maintenance.
• Contrary to the instructions
for use, the equipment
was not sterilized prior to
implantation.
• Use of electrosurgical device
on a pacemaker patient
while deliberately ignoring
the clear warning in the
instructions for use to take
proper precautions, resulting
in the need to re-program
the pacemaker or explant
the device. A pacemaker
Summary of the taxonomy of operator action from IEC 62366
programmer is not available.
• Patient harmed because
with alcohol. It is made from • Failure to stop using an X-ray user had not ensured that
material that is known to be tube after having ignored the the operator was adequately
incompatible with alcohol. It warning light that indicates trained. The equipment is
is reasonably foreseeable that it is overheating. The X-ray working in accordance to
alcohol might be used to clean equipment subsequently specifications.
the pump as alcohol is readily stops operating or fails • During placement of a
available in the hospital. and that delays or prevents pacemaker lead, an untrained
• Unintentional use of pipette completion of a therapeutic physician perforates the
out of its calibration range. procedure. heart.
• Analyser placed in direct • Use of equipment prior • The labelling for a centrifugal
sunlight causing higher to completing installation pump clearly indicates that it
reaction temperature than or the initial performance is intended for use in by-pass
specified. checks as specified by the operations of less than 6 hours
• Technician brings a steel accompanying documents. in duration. Finding no other
oxygen tank into the presence • Deliberate failure to conduct pump available, the clinician
of the magnet in the MRI prescribed device checks decides to use the pump in
system suite and it moves prior to each use as defined a paediatric extra-corporeal
swiftly across the room into by the accompanying membrane oxygenation
the magnet. documents. (ECMO) procedure that can
• Operator is under time • Continued use of equipment last several days. The pump
pressure and uses a shortcut beyond the prescribed fails due to fatigue cracking
on excessively lengthy maintenance interval as and the patient bleeds
instructions, procedures, pre- clearly defined in the to death.
use checklist, etc, thereby
abbreviating them.
Sanjeev Gupta, Head, Regulatory and Certifications, BPL Ltd-Health
Abnormal Use Examples Management Solutions, Bangalore. He has over 15 Years of Experience
from IEC 62366 with Standards and Regulations. He worked on several dozens of
• Deliberate, premeditated Medical Devices in US for last eight years and represented his previous
violation of instructions, organization at IEC and AAMI Human Engineering Committees involved
in development of Standard HE75.
procedures, pre-use checklist,
calibration, or maintenance,
Sanjeev Gupta
etc., as specified in the
accompanying documents.
Medical Equipment & Automation Mar-Apr 2010 93