Classifications of Medical Devices In Health Care Facility

1. Biomedical Instrumentation II
(BMEg-4223)
Institute of Technology
Biomedical Engineering Department
Prepared by: Yared D (Msc.)
4/3/2024

2. Chapter One
Introduction፡
Classifications of Medical
Devices In Health Care Facility

3. Contents of chapter
 Introduction
 Overview of electrical safety testing
 Overview of Earthing System and RCD
 Classification of medical devices into appliance classes
 Classification of medical device in to types
 Overview of Electrical safety test procedures

4. 1.Introduction to Medical Device
A medical device can be any instrument, apparatus, machine, appliance,
implant, reagent for in vitro use, software, material or other similar or
related article, intended by the manufacturer to be used, alone or in
combination for a medical purpose.
What is a medical device ?

5. Cont.….
Medical equipment can be classified in deferent categories. They can be
classified base on
 The method of protection against electric shock
 Medical Purpose they provide
 Their Function and Usage
Classification Of Medical Devices

6. 2.Overview of electrical safety testing
 Manufacturers of medical equipment ensure that all safety regulations
during the design.
 Now it is a task of biomedical engineer to ensure that the medical
equipment remains safe during usage.
 Electrical safety tests are compulsory after installation , preventive
maintenance(PPM) and corrective maintenance (CM) are also done for
medical equipment.

7. Cont.…
 National and international organizations like ANSI, BSI, EEC, IEC,
ISO, NETA, NFPA have defined safety standards and test procedures.
 In Ethiopia Food, Medicine and Health Care Administration and
Control Authority (FMHCACA).

8. Cont.…
 Electrical installation in the hospital is faulty.
 Fuses and RCDs are missing
 Wall sockets are broken and power plugs are
missing
Why safety tests on medical equipment ? while
Do those make the hospital safer?
Situation like this!!!
 Testing methods:
• Visual inspection
• Using testing devices by following testing procedures

9. 3. Overview of Earthing System and RCD
 For safety reasons the electrical installation in hospital building has to
meet certain standards.
 One standard specifies the Earthing system.
Touching only one wire of a
power cable is not enough.
That is why Birds can safely
sit on a high-voltage power
line without getting an electric
shock.
Generator
Or
transformer
The man gets in contact between two voltage potentials. That is why, he got shocked

10. Cont.…
 A (very small) current flows from line, through a neon lamp and a high
Ohmic resistor inside the screwdriver, through the body of the
technician to ground.
How does neon tester or test light work ?

11. Cont.…
 The main characteristic of TN-C-S is the combined PEN connection
to the building and the strict separation of PE (Protective Earth) and
N (Neutral) inside the building.
TN-C-S Earthing system
Generator
Or
transformer

12. Cont.…
 RCD is a safety device which protects humans
against electric shock.
 The RCD detects fault currents and disconnects
all consumers instantly from the supply voltage.
 RCD does not protect connected equipment
from overload, fire and other damage.
 Fuses or circuit breakers (MCB) are still
needed.
Residual-Current Device (RCD)
The man is protected from electric
shock.
What will happen if the line is in contact with the housing ?

13. 4. Classification of medical devices
into classes and types
 All electrical equipment are divided in different appliance classes
depending on the method of protection against electric shock.
 The protection can consist of the usage of:
 For medical equipment this classification is not sufficient enough because a
medical equipment of the same class can be made for the usage of
 Protective earth,
 Double insulation
 Separate power supply.
 Without a connection to a patient,
 With a connection to the patient's skin
 For a connection to the opened body of a patient.

14. Classification of medical devices into classes
 Has a protective earth connection (PE). This earth connection is connected to all
exposed metal parts, especially to the metal housing.
 The connected power cable is thus a three core mains cable and the power plug has
three pins.
 Medical equipment should be additionally protected by two internal fuses, one for
the line path and one for neutral.
Class I

15. Cont.….
 A Class II equipment is double insulated and not earthed.
 Safety is achieved by two (or more) layers of insulating material between
live parts and the user.
 Earthing is not necessary. In case of a damage of one insulation the second
prevents any external parts from becoming alive.
 Usually connected with a 2-pin plug to mains.
 Class II equipment usually have only one internal fuse.
Class II

16. Cont.….
 A Class III equipment is a low-voltage equipment.
 The voltage is so low (Safety Extra Low Voltage) that a person
who gets in contact with it does not get an electric shock.
 The equipment runs either on battery or on an external power
supply which creates a supply voltage of less than 50 VAC.
Class III

17. Classification of medical devices into types
 The equipment classes define the method of protection against shock.
 For household appliances it is good enough but not for medical
equipment.
 A medical equipment of one class can be used:
 Without a connection to a human body (e.g. suction pump),
 With a patient connection (e.g. pulse oximeter, ECG)
 Inside the body of a patient (e.g. electrosurgical unit).

18. Cont.….
 Therefore, the medical equipment in different appliance classes are again
divided in different types. The types define the degree of protection.
 For this reason we find two symbols on the rating plates of medical
equipment, one for the method of protection (class) and one for the
degree of protection (type)
 Medical device type classifications: i. Type B
ii.Type BF
iii.Type CF

19. Cont.….
 In combination with medical equipment of Class I, II, III.
 Standard degree of protection against electric shock. No electrical
contact with a patient. Equipment may be connected to earth.
 Patient connections are not conductive and can be immediately
released from the patient.
 Standard values for permitted leakage currents are demanded which
are stated under the respective test procedure.
Type B
Symbolized by

20. Cont.….
 In combination with medical equipment of Class I, II, III.
 Equipment is safe for electrical connection to the patient but not
directly to the heart.
 The patient part of the equipment is isolated (floating circuit) and has
to be separated from earth.
 Standard values for permitted leakage currents are demanded which
are stated under the respective test procedure
Type BF
When the equipment is used in combination
with a defibrillator: means that defibrillator
proof

21. Cont.….
 In combination with medical equipment of Class I, II, III.
 Equipment provides highest degree of protection against electric
shock.
 It is safe for electrical connection to the heart of the patient.
 The patient part of the equipment is also isolated (floating circuit) and
is separated from earth like BF.
 The permitted leakage current is much lower than for type B and BF.
The values are stated under the respective test procedure.
Type CF
When the equipment is used in combination
with a defibrillator: means that defibrillator
proof

22. 5.Electrical safety test procedures
for medical equipment
 Electrical safety of medical equipment must be tested by using special
testing equipment with experienced technician or engineer.
 These electrical safety tests are:
• Protective earth continuity test
• Insulation resistance test
• Earth leakage current test
• Touch current / Enclosure leakage current test
• Patient leakage current test

23. Cont.…
 Equipment is disconnected from main.
 Continuity tester is connected to the
metal housing of the equipment and to
PE of the mains plug.
 Equipment is switched on.
 The resistance should be ≤ 0.2 Ω
Protective earth continuity test (Class I)

24. Cont.…
 Equipment is disconnected from mains.
 Equipment is switched on.
 Insulation tester is connected between L+N & PE.
 The resistance should be ≥ 2 MΩ (medical
equipment), ≥ 1 MΩ (on electric motor), ≥ 0.3 MΩ
(on equipment with heating element).
Insulation resistance test (Class I)

25. Cont.…
 Equipment is disconnected from mains.
 Equipment is switched off.
 Insulation tester is connected between all
patient cables and exposed metal pieces.
 The resistance should be ≥ 2 MΩ
Insulation resistance test (Class II)

26. Cont.…
Normal condition
 Equipment is switched on.
 Should be done for both Normal polarity and
Reverse polarity
 Leakage current should be ≤ 0.5 mA (B, BF, CF)
Single fault condition - Open neutral, N
 Equipment is switched on.
 Normal polarity.
 Reverse polarity.
 Leakage current should be ≤ 1 mA (B, BF, CF)
Earth leakage current test (Class I))

27. Cont.…
Normal condition
 Equipment is switched on.
 Normal polarity and Reverse polarity.
 Leakage current should be ≤ 0.1 mA (B, BF) ≤ 0.01 mA (CF)
Single fault condition-Open PE (Class I only)
 Equipment is switched on.
 Normal polarity and Reverse polarity.
 Leakage current should be ≤ 0.5 mA (B, BF) ≤ 0.05 mA (CF)
Single fault condition - Open neutral
 Equipment is switched on.
 Normal polarity and Reverse polarity.
 Leakage current should be ≤ 0.5 mA (B, BF) ≤ 0.05 mA (CF)
Touch current / Enclosure leakage current (Class I and Class II)

28. Cont.…
 The hospital personnel should be encouraged to report any
(safety) problem, damage or unusual effect to the technical
department.
 This also applies to damaged plugs and wall sockets as well as
equipment with mains plugs of the wrong type.
What else can be done?

29. 6.Classifying medical equipment
based on its purpose
Medical equipment can be classified based its purpose as
 Monitoring
 Diagnosis
 Treatment
 Rehabilitation

30. cont.…
Monitoring: To measure a number of signals from the body on an ongoing basis,
in order to check for abnormalities.
Diagnosis: To analyze in detail the cause of the patient complaints from
measurements and ‘patient history’. It starts by a suspicion on what is the disease.
Treatment: To take measures to (attempt to) improve the situation and condition
of the patient with respect to his/her complaints.
Rehabilitation: To restore the good health of the patient after the cause of the
complaints have been removed, e.g. POC,after surgery >> physiotherapy
The Purpose of Medical Equipment

31. Cont.….
Classify these medical equipment?
Weight scale
Stethoscope
Infusion pump
Pulse Oximetry
NIBP
Oto/Ophthalmoscope
Nebulizer

32. cont.….
Classify these medical equipment?
Suction Machine Anesthesia Machine Operating Microscope Mechanical Ventilator

33. cont.….
Monitoring
Pulse Oxymeter
CTG
ECG
Weight scale Patient Monitor
Can you list other
monitoring devices?

34. cont.….
Diagnosis
Stethoscope
Ultrasound
CT scan
Mammogram
MRI
ECG NIBP
Oto/Ophthalmoscope
Can you list other
Diagnosis devices?

35. cont.….
Treatment
Suction Machine Defibrillator
Infusion Pump
Infant Incubator
Pacemaker
Can you list other
Diagnosis devices?
Nebulizer

36. cont.….
Rehabilitation
Electro Muscular stimulator Short wave diathermy
Can you list other Rehabilitation devices?
Traction

37. cont.….
Integration between Hospital and Home healthcare
Monitoring blood pressure
for prevention
Body weight
for prevention
Thermometer
for diagnosis

38. 7.Classifying devices based on function
and usage area
 General Bedside Nursing equipment
 Utility Equipment and Medical Gas
System
 Dental and Dental Laboratory
equipment
 Theatre and Surgery equipment
 Ventilation and Anesthesia equipment
 Cardiovascular and Monitoring
equipment
 Gynecology and obstetrics
equipment
 Pediatric equipment
 Physiotherapy equipment
 Dialysis equipment
 Medical Imaging equipment
 Laboratory equipment

39. cont.….
General Bedside Nursing equipment

40. cont.….
Utility Equipment and Medical Gas System
Laundry
Water Distiller
Generator unit Autoclave
Medical Gas
Can you list other Utility Equipment
and Medical Gas devices?

41. cont.….
Dental and Dental Laboratory equipment
Dental Chair unit
Amalgamator
Dental X-ray
Dental furnace
Amalgam separator

42. cont.….
Theatre and Surgery equipment
Electrosurgical Unit
Endoscope
OR light
Operating microscope
Suction Machine
Can you list other Theatre
and Surgery devices?

43. cont.….
Ventilation and Anesthesia equipment
Scavenging System
Mechanical ventilator
Vaporizer
Anesthesia machine

44. cont.….
Cardiovascular and Monitoring equipment
Defibrillator
Physiological/patient monitor
Pacemaker
ECG

45. cont.….
Gynecology and obstetrics equipment
Portable Doppler
Infant Incubator
Vacuum extractor
Cryotherapy
CTG

46. cont.….
Pediatric equipment
Infant weight scale
Radiant warmer
Phototherapy
Infant NIBP
Laryngoscope

47. cont.….
Physiotherapy equipment
Infrared treatment light Electro-muscular stimulator
Therapeutic Ultrasound Short wave diathermy

48. cont.….
Dialysis equipment
Hemodialysis machine
Water supply for haemodialysis

49. cont.….
Medical Imaging equipment
X-ray machine
X-ray- cassette
X-ray film processor

50. cont.….
Medical Imaging equipment
Ultrasound MRI
CT- Scan

51. cont.….
Laboratory equipment
CBC/Hematology analyzer
Centrifuge
VGA
Chemistry machine
Microscope
Tissue processor
Glucometer
Can you list Laboratory
devices?

52. END!!!