Guidance for Part I Trainees taking Physiological Measurement

Institute of Physics & Engineering in Medicine
Guidance for Part 1 Trainees taking
Physiological Measurement
1. The Part 1 Physiological Measurement competencies were written to accommodate the wide range
of measurements and techniques that may be studied. As a consequence, the advice given as to
the standard expected may be variable. The following guidance has been prepared by the IPEM
Examiners for Physiological Measurement, and is offered to help improve the first-time pass rate in
this subject.
2. The portfolio must provide evidence that all the required competencies have been met. Otherwise,
an examiner has to satisfy him/herself during the viva that you have the competencies which are not
fully met in the portfolio.
3. Make sure you include a table or other means of listing the required competencies that crossreferences
where in the portfolio the evidence for each competency is located.
4. Competencies PM 1.1 and PM 1.2 are different. PM 1.1 requires that you demonstrate a broad
understanding of the (1) principles, (2) relevant physiology, and (3) measurement significance of
common physiological measurement procedures.
5. PM 1.2 requires that you demonstrate a detailed understanding of the (1) principles, (2) relevant
physiology and (3) measurement significance of three selected parameters.
6. A broad understanding of common physiological procedures implies a less-detailed understanding
is expected than for the three selected for PM 1.2. Common physiological measurements would be
expected to include non-invasive blood pressure measurement and ECG. Short term
acquaintanceships, in addition to your three main areas, are ideally suited to PM 1.1.
7. In PM 1.1, it is mandatory that among the physiological measurements covered, at least one must
be a pressure measurement, one a flow measurement and one must be electrophysiological.
8. The principles of a physiological measurement procedure would include knowledge of how the
relevant transducers (or electrodes) convert a physical measurement or event into a signal that can
be amplified, processed and displayed and, where appropriate, how that signal would be affected by
transducer position, patient orientation, environmental or other relevant factors.
9. The relevant physiology should put the measurement into a clinical context – why it is done, what is
the physiological state or change that is to be detected, how does that relate to the physical event
detected or measurement actually made (including limitations or assumptions that have to be
made).
10. The measurement significance is expected to include both statistical and clinical significance of the
measurement and the extent to which it affects further patient management.
11. Additional detail required for PM 1.2 is given by PM 1.2.1 – 1.2.6. All six aspects must be covered
for each measurement, unless clearly non-applicable in some specific case. It is accepted that the
amount of detail given to each of PM 1.2.1 – 1.2.6 will vary between the three selected
measurements. The following suggestions are given as to how these competencies might be
achieved.
12. To identify and justify the choice of equipment, you could ask questions such as: Are there
alternatives What are the pros and cons of the various options Is the method used the best
possible Why was this particular technology/manufacturer/model chosen Why is a particular
transducer/ electrode/sensor used Why is the particular electrode/transducer/etc placed where it
is What is its sensitivity pattern within the body How accurately does it have to be positioned
Could the information be obtained from a different position Are there advantages/disadvantages of
different positions
Clinical Scientists' Education and Training Panel
June 2009
1 of 2
Guidance for Part 1 Trainees
Physiological Measurement

13. Hands-on experience is essential. The trainee should actively contribute to the patient
measurement wherever possible and ethical. In most cases, training can progress to “push buttons”
under supervision, or to use the equipment on a normal volunteer, or a test phantom. Where this is
not possible, hands-on experience of using the equipment can be obtained by allowing the trainee
to perform a calibration check or similar.
14. Trainees should understand how the signal can be modified at each step from the actual
physiological change to the final recording or measurement. This might include concepts such as
transducer sensitivity patterns, transfer functions, resonance frequencies, phase changes, analogue
and digital filters and any other signal processing technique appropriate to the measurement. A
trainee should also know about possible interfering signals, where these might come from and how
they can be minimised.
15. Trainees are expected to understand the limitations of the measurements made in terms of
measurement uncertainty, assumptions made, discrepancies between what is actually measured
and what, ideally, is wanted. Sources of artefact and how these might be recognised should be
understood. Measurements should be accompanied by an estimate of the uncertainty and, where
appropriate, the rationale for that estimate. A scientist at this level should never report
measurements with an unjustifiable number of significant figures!
16. The statistical methods used will depend on the context of the three parameters studied in detail, so
no list will be given of what methods a trainee must know. However, an understanding is expected
of the concepts of normal ranges and thresholds and how these are obtained. The significance or
otherwise of measurements close to these threshold(s) should be understood, as should type I and
type II errors.
17. Where routine calibration checks are automatic processes, these are not acceptable for
demonstrating competency PM 1.2.5. Calibrations must be performed with external standards of
pressure, flow, voltage, current or whatever. An understanding would be expected of calibration
standards, offset, linearity, hysteresis, drift and repeatability, and how these affect accuracy and
precision.
18. Where appropriate, the trainee should be involved in reporting. Portfolios might include trial patient
reports written by the trainee at the time, possibly with a discussion of any discrepancy with the
report actually issued. Otherwise, anonymous case studies could illustrate a clinical problem,
discuss how the physiological measurement contributes to patient management and, where
possible, discuss the outcome in the particular case.
19. Electrical safety tests of medical equipment are often automated but the trainee should have a
broad understanding of what these measure, and why. They should have some knowledge of:
20. the general concept of safety in a single fault condition and the need for regular maintenance or
other means to identify a single fault state,
21. what a leakage current is,
22. what the symbols mean, that most commonly appear on the outside of a medical device,
23. what an applied part is and what the designations B, BF and CF signify,
24. the basic principles of electrical safety as applied to medical electrical systems, and as applied to
multiple devices connected to the same patient.
25. about the system for reporting adverse incidents to the MHRA.
26. The trainee should know about the Medical Devices Directive, what is its purpose, what the CE
mark signifies and the role of the MHRA as the Competent Authority in the UK.
27. The trainee would be expected to know about standards and guidelines relevant to the parameters
studied in PM 1.2.
Dr Steve Pye
Chief Examiner
3 rd June 2009
Clinical Scientists' Education and Training Panel
June 2009
2 of 2
Guidance for Part 1 Trainees
Physiological Measurement