IEC 60601-1-10:2007
(Main)Medical electrical equipment — Part 1-10: General requirements for basic safety and essential performance — Collateral standard: Requirements for the development of physiologic closed-loop controllers
Medical electrical equipment — Part 1-10: General requirements for basic safety and essential performance — Collateral standard: Requirements for the development of physiologic closed-loop controllers
Specifies requirements for the development (analysis, design, verification and validation) of a physiologic closed-loop controller (PCLC) as part of a physiologic closed-loop control system (PCLCS) in medical electrical equipment and medical electrical systems to control a physiologic variable.
Appareils électromédicaux — Partie 1-10: Exigences générales pour la sécurité de base et les performances essentielles — Norme collatérale: Exigences pour le développement des régulateurs physiologiques en boucle fermée
Spécifie les exigences pour le développement (analyse, conception, vérification et validation) d'un régulateur physiologique en boucle fermée (RPBF) en tant que partie d'un système physiologique de commande en boucle fermée (SPCBF) dans les appareils em et les systèmes em pour la commande d'une variable physiologique.
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IEC 60601-1-10
Edition 1.0 2007-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment –
Part 1-10: General requirements for basic safety and essential performance –
Collateral Standard: Requirements for the development of physiologic
closed-loop controllers
Appareils électromédicaux –
Partie 1-10: Exigences générales pour la sécurité de base et les performances
essentielles – Norme collatérale: Exigences pour le développement des
régulateurs physiologiques en boucle fermée
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IEC 60601-1-10
Edition 1.0 2007-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment –
Part 1-10: General requirements for basic safety and essential performance –
Collateral Standard: Requirements for the development of physiologic
closed-loop controllers
Appareils électromédicaux –
Partie 1-10: Exigences générales pour la sécurité de base et les performances
essentielles – Norme collatérale: Exigences pour le développement des
régulateurs physiologiques en boucle fermée
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
W
CODE PRIX
ICS 11.040 ISBN 2-8318-9448-4
– 2 – 60601-1-10 © IEC:2007
CONTENTS
FOREWORD.4
INTRODUCTION.7
1 Scope, object and related standards.8
1.1 * Scope .8
1.2 Object .8
1.3 Related standards .8
1.3.1 IEC 60601-1 .8
1.3.2 Particular standards .9
2 Normative references .9
3 Terms and definitions .9
4 * General requirements .14
5 ME EQUIPMENT identification, marking and documents .14
5.1 * Instructions for use .14
5.2 Technical description.15
6 Accuracy of controls and instruments and protection against hazardous outputs .15
6.1 * USABILITY .15
6.2 ALARM SYSTEMS .15
6.3 * PCLCS VARIABLE logging .15
6.4 * DISTRIBUTED PCLCS .16
7 * PROGRAMMABLE ELECTRICAL MEDICAL SYSTEMS (PEMS) .16
8 Requirements for PHYSIOLOGIC CLOSED-LOOP CONTROLLER (PCLC) development.16
8.1 * General.16
8.2 Attributes/activities of the PCLC development PROCESS .17
8.2.1 RECORDS and PROCESS scaling .17
8.2.2 Equipment specifications .17
8.2.3 * Disturbance management.20
8.2.4 * PCLC VERIFICATION.21
8.2.5 * PCLCS VALIDATION .21
Annex A (informative) General guidance and rationale.22
Annex B (informative) Description of dynamic performance of a PCLCS .32
Annex C (informative) Guide to marking and labelling requirements for ME EQUIPMENT
and ME SYSTEMS.36
Bibliography.37
Index of defined terms used in this collateral standard.38
Figure 1 – Functional diagram indicating typical components of a PHYSIOLOGIC CLOSED-
LOOP CONTROL SYSTEM (PCLCS) utilizing a PCLC .10
Figure B.1 – Example of PCLCS dynamic performance with no STEADY-STATE DEVIATION.33
Figure B.2 – Example of PCLCS dynamic performance with STEADY-STATE DEVIATION.34
Figure B.3 – Example of PCLCS dynamic performance transient COMMAND VARIABLE.35
60601-1-10 © IEC:2007 – 3 –
Table A.1 – Examples of ME EQUIPMENT or ME SYSTEMS that incorporate a PCLCS .22
Table C.2 – ACCOMPANYING DOCUMENTS, instructions for use.36
Table C.3 – ACCOMPANYING DOCUMENTS, technical description .36
– 4 – 60601-1-10 © IEC:2007
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –
Part 1-10: General requirements for basic safety
and essential performance –
Collateral Standard:
Requirements for the development of
physiologic closed-loop controllers
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
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Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International standard IEC 60601-1-10 has been prepared by IEC subcommittee 62A:
Common aspects of electrical equipment used in medical practice, of IEC technical committee
62: Electrical equipment in medical practice, and ISO subcommittees SC1: Breathing
attachments and anaesthetic machines, and SC3: Lung ventilators and related devices of ISO
technical committee 121: Anaesthetic and respiratory equipment.
It is published as double logo standard.
This first edition constitutes a collateral standard to IEC 60601-1: Medical electrical
equipment – Part 1: General requirements for safety and essential performance hereafter
referred to as the general standard.
60601-1-10 © IEC:2007 – 5 –
The text of this collateral standard is based on the following documents:
FDIS Report on voting
62A/576/FDIS 62A/585/RVD
Full information on the voting for the approval of this collateral standard can be found in the
report on voting indicated in the above table. In ISO, the standard has been approved by
18 P-members out of 19 having cast a vote.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
In the 60601 series of publications, collateral standards specify general requirements for
safety applicable to:
– a subgroup of MEDICAL ELECTRICAL EQUIPMENT (e.g. radiological equipment); or
– a specific characteristic of all MEDICAL ELECTRICAL EQUIPMENT, not fully addressed in the
general standard (e.g. ALARM SYSTEMS).
In this collateral standard, the following print types are used:
– requirements and definitions: roman type.
– test specifications: italic type.
– informative material appearing outside of tables, such as notes, examples and references: in smaller type.
Normative text of tables is also in a smaller type.
– TERMS DEFINED IN CLAUSE 3 OF THE GENERAL STANDARD, IN THIS COLLATERAL STANDARD OR AS
NOTED: SMALL CAPITALS.
In referring to the structure of this standard, the term
– “clause” means one of the eight numbered divisions within the table of contents, inclusive
of all subdivisions (e.g. Clause 8 includes Subclauses 8.1, 8.2, etc.);
– “subclause” means a numbered subdivision of a clause (e.g. 8.1, 8.2 and 8.2.1 are all
subclauses of Clause 8).
References to clauses within this standard are preceded by the term “Clause” followed by the
clause number. References to subclauses within this standard are by number only.
In this standard, the conjunctive “or” is used as an “inclusive or” so a statement is true if any
combination of the conditions is true.
The verbal forms used in this standard conform to usage described in Annex H of the ISO/IEC
Directives, Part 2. For the purposes of this standard, the auxiliary verb:
– “shall” means that compliance with a requirement or a test is mandatory for compliance
with this standard;
– “should” means that compliance with a requirement or a test is recommended but is not
mandatory for compliance with this standard;
– “may” is used to describe a permissible way to achieve compliance with a requirement or
test.
Clauses, subclauses and definitions for which a rationale is provided in informative Annex A
are marked with an asterisk (*).
A list of all parts of the IEC 60601 series, published under the general title: Medical electrical
equipment, can be found on the IEC website.
– 6 – 60601-1-10 © IEC:2007
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended
60601-1-10 © IEC:2007 – 7 –
INTRODUCTION
The use of PHYSIOLOGIC CLOSED-LOOP CONTROLLERS in ME EQUIPMENT and ME SYSTEMS are
expected to provide a successful strategy to improve PATIENT safety and reduce healthcare
)
costs [9][10][11][12][13] . New RISKS that are not directly addressed by previous standards
are emerging in the development of this equipment. MANUFACTURERS employ a variety of
methods to validate the safety and integrity of control systems with varying degrees of
success. Classical methods of software VALIDATION for PHYSIOLOGIC CLOSED-LOOP
CONTROLLERS can be insufficient to ensure performance with acceptable RISKS under all
clinical and physiologic conditions.
—————————
)
Figures in square brackets refer to the Bibliography.
– 8 – 60601-1-10 © IEC:2007
MEDICAL ELECTRICAL EQUIPMENT –
Part 1-10: General requirements for basic safety
and essential performance –
Collateral Standard:
Requirements for the development of
physiologic closed-loop controllers
1 Scope, object and related standards
1.1 * Scope
This International Standard applies to the BASIC SAFETY and ESSENTIAL PERFORMANCE of
MEDICAL ELECTRICAL EQUIPMENT and MEDICAL ELECTRICAL SYSTEMS, hereafter referred to as
ME EQUIPMENT and ME SYSTEMS.
This collateral standard specifies requirements for the development (analysis, design,
VERIFICATION and VALIDATION) of a PHYSIOLOGIC CLOSED-LOOP CONTROLLER (PCLC) as part of a
PHYSIOLOGIC CLOSED-LOOP CONTROL SYSTEM (PCLCS) in ME EQUIPMENT and ME SYSTEMS to
control a PHYSIOLOGIC VARIABLE.
NOTE A PHYSIOLOGIC VARIABLE can be a body chemistry (e.g. electrolytes, blood glucose), a physical property
(e.g. PATIENT temperature, electrophysiologic, hemodynamic), or a pharmaceutical concentration.
This collateral standard applies to various types of PCLC, e.g. linear and non-linear, adaptive,
fuzzy, neural networks.
This collateral standard does not specify:
− additional mechanical requirements; or
− additional electrical requirements.
This collateral standard applies to a closed-loop controller (see Figure 1) that sets the
CONTROLLER OUTPUT VARIABLE in order to adjust (i.e., change or maintain) the measured
PHYSIOLOGIC VARIABLE by relating it to the REFERENCE VARIABLE.
A closed-loop controller that maintains a physical or chemical VARIABLE, using feedback that is
not measured from a PATIENT, is outside the scope of this standard.
1.2 Object
The object of this collateral standard is to specify general requirements that are in addition to
those of the general standard and to serve as the basis for particular standards.
1.3 Related standards
1.3.1 IEC 60601-1
For ME EQUIPMENT and ME SYSTEMS, this collateral standard complements IEC 60601-1.
When referring to IEC 60601-1 or to this collateral standard, either individually or in
combination, the following conventions are used:
− "the general standard" designates IEC 60601-1 alone;
− "this collateral standard" designates IEC 60601-1-10 alone;
60601-1-10 © IEC:2007 – 9 –
− "this standard" designates the combination of the general standard and this collateral
standard.
1.3.2 Particular standards
A requirement in a particular standard takes priority over the corresponding requirement in
this collateral standard.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60601-1:2005, Medical electrical equipment – Part 1: General requirements for basic
safety and essential performance
IEC 60601-1-6:2006, Medical electrical equipment – Part 1-6: General requirements for basic
safety and essential performance – Collateral Standard: Usability
IEC 60601-1-8:2006, Medical electrical equipment – Part 1-8: General requirements for basic
safety and essential performance – Collateral Standard: General requirements, tests and
guidance for alarm systems in medical electrical equipment and medical electrical systems
IEC 62304:2006, Medical device software – Software life cycle processes
ISO 14971, Medical devices – Application of risk management to medical devices
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60601-1:2005,
IEC 60601-1-6:2006, IEC 60601-1-8:2006 and the following apply.
NOTE An index of defined term used in this collateral standard is found beginning on page 38.
3.1
ACTUATOR
A
part of a PCLCS that performs a specified output function (see, for example, Figure 1, A)
EXAMPLE 1 A heater delivers thermal energy.
EXAMPLE 2 An infusion pump delivers a fluid or drug.
EXAMPLE 3 An anaesthetic agent vaporizer delivers a vapour concentration.
EXAMPLE 4 A ventilator delivers an inspiratory volume.
3.2
COMMAND OVERSHOOT
y
co
for a step response, the maximum positive deviation of the PHYSIOLOGIC VARIABLE (y), from the
COMMAND VARIABLE (c)
NOTE See also Annex B.
– 10 – 60601-1-10 © IEC:2007
v
p
PCLC
c m
w ex y
+
C D E A P
-
f
F
IEC 2068/07
Elements VARIABLES
PCLC PHYSIOLOGIC CLOSED-LOOP CONTROLLER
A ACTUATOR
m MANIPULATED VARIABLE
C COMMAND TRANSFER ELEMENT w REFERENCE VARIABLE
D COMPARING ELEMENT e ERROR VARIABLE
E CONTROL TRANSFER ELEMENT x CONTROLLER OUTPUT VARIABLE
F MEASURING TRANSFER ELEMENT f FEEDBACK VARIABLE
P PATIENT TRANSFER ELEMENT y PHYSIOLOGIC VARIABLE
v PATIENT DISTURBANCE VARIABLE
p
c COMMAND VARIABLE
NOTE DISTURBANCE VARIABLES (v), not shown, can act on any element or VARIABLE.
Figure 1 – Functional diagram indicating typical components of a PHYSIOLOGIC CLOSED-
LOOP CONTROL SYSTEM (PCLCS) utilizing a PCLC
3.3
* COMMAND TRANSFER ELEMENT
C
part of a PCLCS that provides an output having a deterministic relationship to the COMMAND
VARIABLE (c) (see, for example, Figure 1, C)
3.4
* COMMAND VARIABLE
c
VARIABLE which, after signal conversion or other processing by the COMMAND TRANSFER
ELEMENT (C), gives the REFERENCE VARIABLE (w) (see, for example, Figure 1, c)
3.5
* COMPARING ELEMENT
D
element with two inputs and one output, the output VARIABLE being the difference between the
input VARIABLES (see, for example, Figure 1, D)
[IEC 60050-351, definition 351-28-03, modified]
NOTE The difference can be simple subtraction, classification within a value range, or a complex relationship
such as results from a neural network calculation.
3.6
CONTROL TRANSFER ELEMENT
E
part of a PCLC that provides an output having a deterministic relationship to the FEEDBACK
VARIABLE (f) (see, for example, Figure 1, E)
60601-1-10 © IEC:2007 – 11 –
3.7
CONTROLLER OUTPUT VARIABLE
x
VARIABLE of the CONTROL TRANSFER ELEMENT (E), which is also an input VARIABLE of the
ACTUATOR (A) (see, for example, Figure 1, x)
3.8
* DISTRIBUTED PCLCS
PCLCS that involves more than one item of equipment of a ME SYSTEM
NOTE The parts of a DISTRIBUTED PCLCS can be widely separated in distance.
3.9
* DISTURBANCE VARIABLE
v
VARIABLE acting on a PCLCS that is independent of the other VARIABLES of the PCLCS (see, for
example, Figure 1, v and v )
p
NOTE 1 DISTURBANCE VARIABLES are undesired, independent, and most frequently unpredictable from the
perspective of the PCLC. The MANUFACTURER or OPERATOR can be aware of DISTURBANCE VARIABLES.
NOTE 2 The MANUFACTURER needs to identify the DISTURBANCE VARIABLES that are relevant to the PCLC, but their
values are usually unpredictable.
3.10
ERROR VARIABLE
e
difference between the REFERENCE VARIABLE (w) and the FEEDBACK VARIABLE (f) (see, for
example, Figure 1, e)
[IEC 60050-351, definition 351-27-04]
3.11
* FALLBACK MODE
mode of operation (or state) into which the PCLCS transitions when the PCLC stops operating
due to detection of a fault
3.12
FEEDBACK VARIABLE
f
output of the MEASURING TRANSFER ELEMENT (F) (see, for example, Figure 1, f)
[IEC 60050-351, definition 351-27-03, modified]
3.13
INTERPATIENT VARIABILITY
variability of the PATIENT TRANSFER ELEMENT between PATIENTS
EXAMPLE The reaction of PATIENTS to the same amount of a certain drug can vary widely.
3.14
INTRAPATIENT VARIABILITY
variability of the PATIENT TRANSFER ELEMENT within the same PATIENT over time
EXAMPLE The reaction of a PATIENT to a dose of a drug that varies widely during the day.
– 12 – 60601-1-10 © IEC:2007
3.15
MANIPULATED VARIABLE
m
output of the ACTUATOR (A), which is also an input VARIABLE of the PATIENT TRANSFER ELEMENT
(see, for example, Figure 1, m)
[IEC 60050-351, definition 351-27-07, modified]
3.16
MEASURING TRANSFER ELEMENT
F
part of a PCLCS that provides an output having a determined relationship to the PHYSIOLOGIC
VARIABLE (y) (see, for example, Figure 1, F)
EXAMPLE 1 thermocouple
EXAMPLE 2 current transformer
EXAMPLE 3 strain gauge
EXAMPLE 4 pH electrode
EXAMPLE 5 pulse oximeter
EXAMPLE 6 respiratory gas monitor
EXAMPLE 7 heart rate monitor
EXAMPLE 8 blood pressure monitor
EXAMPLE 9 EEG monitor
EXAMPLE 10 EMG monitor
EXAMPLE 11 cardiac output monitor
3.17
* PATIENT DISTURBANCE VARIABLE
v
p
DISTURBANCE VARIABLE, independent of the MANIPULATED VARIABLE (m), which changes the
PATIENT TRANSFER ELEMENT (P) (see, for example, Figure 1, v )
p
3.18
PATIENT TRANSFER ELEMENT
P
relationship of the change of the PHYSIOLOGIC VARIABLE (y) in response to a change in the
MANIPULATED VARIABLE (m) (see, for example, Figure 1, P)
3.19
PHYSIOLOGIC CLOSED-LOOP CONTROL SYSTEM
PCLCS
part of ME EQUIPMENT or ME SYSTEM used to adjust a PHYSIOLOGIC VARIABLE (y) relative to a
COMMAND VARIABLE (c) using a FEEDBACK VARIABLE (f) (see, for example, Figure 1)
3.20
* PHYSIOLOGIC CLOSED-LOOP CONTROLLER
PCLC
element of a PHYSIOLOGIC CLOSED-LOOP CONTROL SYSTEM in which a FEEDBACK VARIABLE (f) is
compared with a REFERENCE VARIABLE (w), and their difference is transformed to set the
CONTROLLER OUTPUT VARIABLE (x) (see, for example, Figure 1, PCLC)
60601-1-10 © IEC:2007 – 13 –
3.21
PHYSIOLOGIC VARIABLE
y
quantity or condition from a PATIENT whose value is subject to change and can usually be
measured
NOTE A PHYSIOLOGIC VARIABLE can be a body chemistry (e.g. electrolytes, blood glucose), a physical property
(e.g. PATIENT temperature, electrophysiologic, hemodynamic), or a pharmaceutical concentration.
3.22
* REFERENCE VARIABLE
w
input VARIABLE to a COMPARING ELEMENT (D) in a PCLC that sets the desired value of the
PHYSIOLOGIC VARIABLE (y) (see, for example, Figure 1, w)
[IEC 60050-351, definition 351-27-02, modified]
3.23
RELATIVE OVERSHOOT
y
ro
for a step response, the maximum transient deviation from the final steady-state value of the
PHYSIOLOGIC VARIABLE (y), expressed as the difference between the final and the initial steady-
state values
NOTE 1 The initial steady-state value is the value of the PHYSIOLOGIC VARIABLE prior to applying the step.
NOTE 2 See also Annex B.
[IEC 60050-351, definition 351-24-30, modified]
3.24
RESPONSE TIME
T
r
time required for the step response of the PHYSIOLOGIC VARIABLE (y) to move from its initial
value to a specified percentage of the final steady-state value
NOTE 1 The time is measured from the point in time that the step is applied.
NOTE 2 The conventional value for the percentage is 90 %.
NOTE 3 See also Annex B.
3.25
SETTLING TIME
T
st
duration of the time interval between the instant of a step change in one of the input
VARIABLES and the instant when the PHYSIOLOGIC VARIABLE (y) does not deviate by more than a
specified tolerance from the difference between its final and initial steady-state values
NOTE 1 The conventional value for the tolerance is 5 %.
NOTE 2 See also Annex B.
[IEC 60050-351, definition 351-24-29, modified]
3.26
STEADY-STATE DEVIATION
y
sd
deviation between PHYSIOLOGIC VARIABLE (y) and COMMAND VARIABLE (c) when transient effects
have subsided and the COMMAND VARIABLE is maintained constant
NOTE See also Annex B.
– 14 – 60601-1-10 © IEC:2007
3.27
TRACKING ERROR
E
tr
deviation of the PHYSIOLOGIC VARIABLE (y) from the COMMAND VARIABLE (c) as a function of time
NOTE See also Annex B.
3.28
VARIABLE
quantity or condition whose value is subject to change and can usually be measured
[IEC 60050-351, definition 351-21-01]
4 * General requirements
When performing the HAZARD identification step of the RISK MANAGEMENT PROCESS required by
4.2 of the general standard, the analysis shall consider HAZARDS from a PCLC in the PCLCS with
particular emphasis placed on the following:
– * latency times;
– ACTUATOR, including starting and stopping;
– MANIPULATED VARIABLE:
• safe ranges of delivered substances and energy, and
• cumulative effects of delivered substances and energy;
– PATIENT TRANSFER ELEMENT, including any hysteresis;
PHYSIOLOGIC VARIABLE;
–
– INTERPATIENT VARIABILITY;
INTRAPATIENT VARIABILITY;
–
– DISTURBANCE VARIABLE, including the PATIENT DISTURBANCE VARIABLE;
MEASURING TRANSFER ELEMENT;
–
– FEEDBACK VARIABLE;
– the necessary resolution and duration of the log required to analyze the performance of a
PCLCS (see 6.3);
– * for a DISTRIBUTED PCLCS, additional parameters which can influence the PCLC
performance (see 6.4); and
– for a PCLCS with more than one PCLC, interaction between CONTROL TRANSFER ELEMENTS.
NOTE See also 8.1.
Compliance is checked by inspection of the RISK MANAGEMENT FILE.
5 ME EQUIPMENT identification, marking and documents
5.1 * Instructions for use
In addition to the requirements in 7.9.2.5 of the general standard for the ME EQUIPMENT
description, the instructions for use shall contain the following:
– PCLCS basic theory of operation; and
– essential assumptions, conditions, or premises built into the PCLC sufficient for OPERATORS
to develop a mental model of the operation of the PCLCS.
60601-1-10 © IEC:2007 – 15 –
See Table C.2 for a cross-reference to the subclauses of this collateral standard that specify
requirements for information to be included in the instructions for use portion of the
ACCOMPANYING DOCUMENTS.
Compliance is checked by inspection of the instructions for use and the USABILITY
ENGINEERING FILE according to IEC 60601-1-6.
5.2 Technical description
See Table C.3 for a cross-reference to the subclauses of this collateral standard that specify
requirements for information to be included in the technical description portion of the
ACCOMPANYING DOCUMENTS.
6 Accuracy of controls and instruments and protection against hazardous
outputs
6.1 * USABILITY
A PCLCS shall indicate the following information continuously or by OPERATOR action:
– the current value of:
– COMMAND VARIABLE or REFERENCE VARIABLE,
– CONTROLLER OUTPUT VARIABLE or MANIPULATED VARIABLE, and
– PHYSIOLOGIC VARIABLE or FEEDBACK VARIABLE;
– the PCLC mode of operation; and
– an indication over time of the values of the above displayed VARIABLES over time.
However, the indication over time may be omitted if its absence does not lead to an
unacceptable RISK (see also 6.3).
The PHYSIOLOGIC VARIABLE or FEEDBACK VARIABLE shall be indicated in the same units of
measure as the COMMAND VARIABLE or REFERENCE VARIABLE.
To minimize RISKS arising from NORMAL USE, the presentation format and the choice between
indicating the information continuously or by OPERATOR action shall be based on the USABILITY
ENGINEERING PROCESS according to IEC 60601-1-6.
Compliance is checked by functional testing and an inspection of the USABILITY ENGINEERING
FILE and the RISK MANAGEMENT FILE.
6.2 ALARM SYSTEMS
ME EQUIPMENT and ME SYSTEMS that incorporate a PCLC shall include an ALARM SYSTEM that
informs the OPERATOR when the PCLCS assumes a FALLBACK MODE.
NOTE See IEC 60601-1-8.
Compliance is checked by functional testing.
6.3 * PCLCS VARIABLE logging
ME EQUIPMENT or ME SYSTEMS that incorporate a PCLC shall provide a means to log the values
of at least the COMMAND VARIABLE or REFERENCE VARIABLE, CONTROLLER OUTPUT VARIABLE or
MANIPULATED VARIABLE, and PHYSIOLOGIC VARIABLE or FEEDBACK VARIABLE. The log is necessary
to analyze the performance of the PCLCS. The resolution and duration of the log shall be
based on HAZARDS identified in Clause 4. The log should be capable of storing the information
for a reasonable period of time.
NOTE The log is necessary to analyze the performance of the PCLCS.
– 16 – 60601-1-10 © IEC:2007
EXAMPLE 1 The intended duration of use on a single PATIENT.
EXAMPLE 2 The sample rate.
EXAMPLE 3 The minimum resolvable unit of data.
The MANUFACTURER shall disclose the following in the instructions for use:
– the resolution and duration of the log and the VARIABLES stored;
– whether the log is maintained when the ME EQUIPMENT or ME SYSTEM is powered down; and
– what happens to the contents of the log after the ME EQUIPMENT or ME SYSTEM has
experienced a total loss of power (SUPPLY MAINS and/or INTERNAL ELECTRICAL POWER
SOURCE) for a finite duration.
Compliance is checked by inspection of the instructions for use and functional testing.
6.4 * DISTRIBUTED PCLCS
The details necessary for the safe use of a DISTRIBUTED PCLCS shall be disclosed in the
technical description. A DISTRIBUTED PCLCS is a permitted form of a PCLCS.
A PCLCS is permitted to send or receive VARIABLES or other data to or from other parts of a
DISTRIBUTED PCLCS. One or more parts of a DISTRIBUTED PCLCS are permitted to be located
outside of the PATIENT ENVIRONMENT. Data are permitted to be transmitted between different
parts of a DISTRIBUTED PCLCS by wire, by telemetry or by other means.
Compliance is checked by inspection of the technical description.
7 * PROGRAMMABLE ELECTRICAL MEDICAL SYSTEMS (PEMS)
For ME EQUIPMENT and ME SYSTEMS that incorporate a PCLC and incorporate PEMS, when the
requirements of Clause 14 of the general standard apply to PEMS, the requirements of
PROGRAMMABLE ELECTRONIC SUBSYSTEM
IEC 62304:2006 shall apply to the software for each
(PESS) in addition to the other requirements of Clause 14 of the general standard.
Compliance is checked by application of the requirements of IEC 62304:2006.
8 Requirements for PHYSIOLOGIC CLOSED-LOOP CONTROLLER (PCLC) development
8.1 * General
A PCLC development PROCESS shall be conducted to avoid unacceptable RISK to the PATIENT,
OPERATOR and other persons related to operation of the ME EQUIPMENT or ME SYSTEM with a
PCLC in NORMAL CONDITION and any SINGLE FAULT CONDITION.
If the PCLC development PROCESS detailed in this standard has been complied with, then the
RESIDUAL RISKS associated with the use of the PCLCS are presumed to be acceptable, until
such time that there is OBJECTIVE EVIDENCE to the contrary.
In any SINGLE FAULT CONDITION that would create an unacceptable RISK related to the
performance of the PCLC, the PCLCS shall assume a FALLBACK MODE.
NOTE A FALLBACK MODE can be reached, for example, by stopping operation, by setting the CONTROLLER OUTPUT
VARIABLE to a safe value, or by going into open-loop control. See also 8.2.2.3.
ME EQUIPMENT or ME SYSTEMS that incorporate a PCLC may also operate without using the
PCLC. ME EQUIPMENT or ME SYSTEMS that incorporate a PCLC and can also operate in a mode
without using the PCLC shall clearly indicate which mode of operation is in use.
60601-1-10 © IEC:2007 – 17 –
Compliance with this subclause is considered to exist when compliance with 8.2 is
demonstrated.
8.2 Attributes/activities of the PCLC development PROCESS
8.2.1 RECORDS and PROCESS scaling
In addition to the RECORDS and documents required by ISO 14971 and IEC 62304:2006, the
RECORDS and documents produced from application of the PCLC development PROCESS shall
be established and maintained to provide evidence of conformity to requirements of this
collateral standard and shall form part of the RISK MANAGEMENT FILE.
The PCLC development PROCESS may vary in form and extent based on the nature of the PCLC,
its intended OPERATOR and its INTENDED USE. In the case of a modification to a PCLC design,
the PCLC development PROCESS may be scaled up or scaled down, based on the significance
of the modification as determined by the results of the RISK ANALYSIS.
Compliance is checked by inspection of the RISK MANAGEMENT FILE.
8.2.2 Equipment specifications
8.2.2.1 * Application specification
The MANUFACTURER shall specify the application of the ME EQUIPMENT or ME SYSTEM that
incorporates a PCLC.
This specification shall include:
– intended medical indication;
EXAMPLE 1 Condition(s) or disease(s) to be screened, monitored, treated, diagnosed or prevented.
– intended PATIENT population;
EXAMPLE 2 age
EXAMPLE 3 weight
EXAMPLE 4 health
EXAMPLE 5 condition
– intended part of the body or type of tissue applied to or interacted with;
– if applicable, intended OPERATOR PROFILE;
– intended conditions of use; and
EXAMPLE 6 environment
EXAMPLE 7 frequency of use
EXAMPLE 8 location
EXAMPLE 9 mobility
– required devices.
EXAMPLE 10 additional monitoring
NOTE This specification contains elements of the INTENDED USE.
A summary of this specification shall be included in the instructions for use.
Compliance is checked by inspection of the RISK MANAGEMENT FILE and the instructions for
use.
– 18 – 60601-1-10 © IEC:2007
8.2.2.2 * State VARIABLES
The MANUFACTURER shall characterize the following attributes:
– COMMAND VARIABLE or REFERENCE VARIABLE;
– CONTROLLER OUTPUT VARIABLE or MANIPULATED VARIABLE;
– PHYSIOLOGIC VARIABLE or FEEDBACK VARIABLE;
– the limits of the range of the PATIENT TRANSFER ELEMENT; and
– the PCLC modes of operation.
Compliance is checked by inspection of the RISK MANAGEMENT FILE.
8.2.2.3 * FALLBACK MODE
The MANUFACTURER shall specify all FALLBACK MODES of the PCLCS. In the FALLBACK MODE there
shall be no unacceptable RISK.
NOTE A FALLBACK MODE can be reached, for example, by stopping operation, by setting the CONTROLLER OUTPUT
VARIABLE to safe values, or by going into open loop control.
A summary of any FALLBACK MODES shall be included in the instructions for use.
Compliance is checked by inspection of the RISK MANAGEMENT FILE and the instructions for
use.
8.2.2.4 * Specification of operating conditions
The operating conditions under which the performance specifications of the PCLC can be
ensured shall be specified.
Compliance is checked by inspection of the RISK MANAGEMENT FILE.
8.2.2.5 * Limitation of the MANIPULATED VARIABLE
If necessary, measures shall be taken or means shall be provided to eliminate, control, or
decrease RISKS to acceptable levels by controlling:
– the range of the MANIPULATED VARIABLE;
– the integral over a period of time of the MANIPULATED VARIABLE; or
– the rate of change of the MANIPULATED VARIABLE.
EXAMPLE 1 The range of the MANIPULATED VARIABLE of a PCLCS where the intended purpose is controlling a
PATIENT'S body temperature to a maximum and minimum.
EXAMPLE 2 EEG-controlled anaesthesia where the PATIENT'S anaesthesia is manipulated by a sedative-hypnotic
agent. The maximum amount of sedative-hypnotic agent delivered to the PATIENT during a given period of time is
limited.
EXAMPLE 3 The rate of change of the MANIPULATED VARIABLE of a PCLCS, where the intended purpose is to warm
a PATIENT, is limited to a maximum rate to avoid burning the skin of the PATIENT.
A description of these measures or means shall be disclosed in the instructions for use.
Compliance is checked by inspection of the RISK MANAGEMENT FILE, functional testing, and
inspection of the instructions for use.
60601-1-10 © IEC:2007 – 19 –
8.2.2.6 * Responses of the PCLCS
The responses of the PCLCS shall be specified during NORMAL USE, including worst-case
combination of changes of the COMMAND VARIABLE or FEEDBACK VARIABLE and worst-case
PATIENT TRANSFER ELEMENT.
NOTE The worst-case PATIENT TRANSFER ELEMENT is limited by the specified NORMAL USE.
The specifications shall include, if applicable:
SETTLING TIME;
–
– RELATIVE OVERSHOOT;
COMMAND OVERSHOOT;
–
– RESPONSE TIME;
STEADY-STATE DEVIATION;
–
– TRACKING ERROR.
NOTE The effects of physiological hysteresis on the response and frequency response of elements of the PCLCS
should be considered.
If the PHYSIOLOGIC VARIABLE is not measured directly, the FEEDBACK VARIABLE may be used to
PCLCS responses.
determine the
The PCLCS shall have a means of indicating to the OPERATOR its mode of operation. If the PCLC
changes its mode of operation, the PCLCS shall have a means of notifying the OPERATOR of its
change in mode of operation. An INFORMATION SIGNAL or ALARM CONDITION may be used. RISK
ANALYSIS shall determine the choice between an INFORMATION SIGNAL and an ALARM CONDITION
and its priority.
EXAMPLE 1 A learning mode where the PCLC assesses the PATIENT’S sensitivity to the therapy.
EXAMPLE 2 A CONTROL TRANSFER ELEMENT gain change (low, medium, high) as a function of the range of the
error.
EXAMPLE 3 A CONTROL TRANSFER ELEMENT change (gain change low to high or high to low) as a function of the
amount of measured noise.
These specifications and a summary of modes of operation of the PCLCS and a description of
the means for checking these behaviours shall be disclosed in the technical description.
Compliance is checked by inspection of the RISK MANAGEMENT FILE, functional testing, and
inspection of the technical description.
8.2.2.7 * Range limitation of PHYSIOLOGIC VARIABLE
In order to eliminate, control, or reduce RISKS to acceptable levels in NORMAL CONDITION and
SINGLE FAULT CONDITION, the PCLCS shall be provided with means to:
a) monitor the value of the PHYSIOLOGIC VARIABLE within its acceptable range; or
b) limit the value of the:
– MANIPULATED VARIABLE, or
– CONTROLLER OUTPUT VARIABLE.
If the value of the PHYSIOLOGIC VARIABLE exceeds its specified range, the PCLCS shall switch
into a FALLBACK MODE. See also 6.2.
The range of limitation of the CONTROLLER OUTPUT VARIABLE or MANIPULATED VARIABLE or the
PHYSIOLOGIC VARIABLE shall be disclosed in the instructions for use.
means to monitor a
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