Active Medical Devices - An example of an Active Medical Device and Definition

Ajit Basrur

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Welocme to the Cove :)

You can find lot of info on AIMD HERE and has lot of examples too.

The classic definition - 'active implantable medical device' means any active medical device which is intended to be totally or partially introduced, surgically or medically, into the human body or by medical intervention into a natural orifice, and which is intended to remain after the procedure is very simple for understanding.
 
O

ODISSEAS

Happy New Year¡

I would like to give a broader answer. Since questions is focused just on "active MD", more than implantable, the reading of directive makes fall into this scope a great variety of devices: from lounge ventillators to exploration pen-lamps.
 
W

wrodnigg

As always, I would recommend reading the relevant MedDev "Guidance document", in this case: MEDDEV 2.4/1 Rev.8 "GUIDELINES FOR THE CLASSIFICATION OF MEDICAL DEVICES" (attached)

There is an explanation to the MMDs definition:

Any medical device the operation of which depends on a source of electrical energy or any source of power other than that directly generated by the human body or gravity and which acts by converting this energy. Medical devices intended to transmit energy, substances or other elements between an active medical device and the patient, without any significant change, are not considered to be active medical devices.


The concept “act by converting energy” includes conversion of energy in the device and/or conversion at the interface between the device and the tissues or in the tissues.
The concept of “significant changes” includes changes in the nature, level and density of energy (see rule 9). This means that for instance an electrode is not an active device under this classification system as long as the energy input is intended to be the same as the energy output. For instance, resistance in a wire that causes minor changes between input and output cannot be considered to constitute "significant change". For example electrodes used in electrosurgery for cutting tissues or cauterisation are active devices because their operation depends on energy provided by a generator and their action is achieved by conversion of energy at the interface between the device and the tissue or in the tissue. Electrodes intended for E.C.G. or E.E.G are normally not active devices because they do not normally act by conversion of energy. However, it should be understood that an electrode, which is an accessory of an active implant, is covered under the relevant directive for active implants. Further information on this issue can be found in "Guidelines relating to the application of the Council Directive 90/385/EEC on active implantable medical devices (Med.Dev. 2.1/2).

The application of energy from the human body does not make a device "active" unless that energy is stored within the device for subsequent release. For instance, energy generated by human muscle and applied to the plunger of a syringe (thus causing a substance to be delivered to a patient) does not make this syringe an "active device". However, if a drug delivery system depends upon manual winding to preload a spring which is subsequently released to deliver a substance, then the device incorporating the spring is an "active device".

Medical devices using prestored gases and/or vacuum as a power source are regarded as active devices, e.g. gas mixers with anesthesia machines and gas powered suction pumps.

Heating/cooling pads intended only to release stored thermal energy are not active devices because they do not act by conversion of energy. However, heating/cooling pads which act by chemical action (e.g. endothermic or exothermic reaction) are active devices as they are converting chemical energy into heat energy and or vice versa.

Radioactive sources that are intended to deliver ionizing radiation are regarded as active medical devices, unless they are radiopharmaceuticals as defined in article 2 of Directive 89/343/EEC or radioactive implants as defined in article 1 of Directive 90/385/EEC.

In part 2 of the MedDev there are plenty examples of devices and their classification.
 

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