A medical device is a product which is used for medical purposes in patients, in diagnosis, therapy or surgery. If applied to the body, the effect of the medical device is primarily physical, in contrast to pharmaceutical drugs, which exert a biochemical effect. Specific regional definitions of medical device vary slightly as detailed below. The medical devices are included in the category: Medical technology.
Medical devices include a wide range of products varying in complexity and application. Examples include tongue depressors, medical thermometers, blood sugar meters, total artificial hearts, fibrin scaffolds, stents and X-ray machines.
 European Union legal framework and definition
Based on the "New Approach", rules relating to the safety and performance of medical devices were harmonised in the EU in the 1990s. The "New Approach", defined in a European Council Resolution of May 1985, represents an innovative way of technical harmonisation. It aims to remove technical barriers to trade and dispel the consequent uncertainty for economic operators allowing for the free movement of goods inside the EU.
The core legal framework consists of 3 directives:
- Directive 90/385/EEC regarding active implantable medical devices;
- Directive 93/42/EEC regarding medical devices;
- Directive 98/79/EC regarding in vitro diagnostic medical devices.
They aim at ensuring a high level of protection of human health and safety and the good functioning of the Single Market. These 3 main directives have been supplemented over time by several modifying and implementing directives, including the last technical revision brought about by Directive 2007/47 EC.
Directive 2007/47/ec defines a medical device as: "any instrument, apparatus, appliance, software, material or other article, whether used alone or in combination, including the software intended by its manufacturer to be used specifically for diagnostic and/or therapeutic purposes and necessary for its proper application, intended by the manufacturer to be used for human beings. Devices are to be used for the purpose of:
- Diagnosis, prevention, monitoring, treatment or alleviation of disease.
- Diagnosis, monitoring, treatment, alleviation of or compensation for an injury or handicap.
- Investigation, replacement or modification of the anatomy or of a physiological process
- Control of conception
This includes devices that do not achieve its principal intended action in or on the human body by pharmacological, immunological or metabolic means, but which may be assisted in its function by such means."
The government of each Member State is required to appoint a Competent Authority responsible for medical devices. The Competent Authority (CA) is a body with authority to act on behalf of the government of the Member State to ensure that the requirements of the Medical Device Directives are transposed into National Law and are applied. The Competent Authority reports to the Minister of Health in the Member State. â€¢ The Competent Authority in one Member State does not have jurisdiction in any other Member State, but they do exchange information and try to reach common positions.
In UK the Medicines and Healthcare products Regulatory Agency (MHRA) acts as a CA, in Italy it is the Ministero Salute (Ministry of Health)
Medical devices must not be mistaken with medicinal products. In the EU, all medical devices must be identified with the CE mark.
 Definition in USA by the Food and Drug Administration
A medical device, according to the U.S. Food and Drug Administration (FDA), is an instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including a component part, or accessory which is:
- recognized in the official National Formulary, or the United States Pharmacopoeia, or any supplement to them,
- intended for use in the diagnosis of disease or other conditions, or in the cure, mitigation, treatment, or prevention of disease, in human or other animals, or
- intended to affect the structure or any function of the body of man or other animals, and which does not achieve any of its primary intended purposes through chemical action within or on the body of man or other animals and which is not dependent upon being metabolized for the achievement of any of its primary intended purposes.
as defined by the Federal Food, Drug, and Cosmetic Act, 21 United States Code  (h). Medical devices are regulated by the FDA Center for Devices and Radiological Health (CDRH).
 Definition in Canada by the Food and Drugs Act
The term medical devices, as defined in the Food and Drugs Act, covers a wide range of health or medical instruments used in the treatment, mitigation, diagnosis or prevention of a disease or abnormal physical condition. Health Canada reviews medical devices to assess their safety, effectiveness and quality before being authorized for sale in Canada.
The regulatory authorities recognize different classes of medical devices, based on their design complexity, their use characteristics, and their potential for harm if misused. Each country or region defines these categories in different ways. The authorities also recognize that some devices are provided in combination with drugs, and regulation of these combination products takes this factor into consideration.
The Medical Devices Bureau of Health Canada has recognized four classes of medical devices based on the level of control necessary to assure the safety and effectiveness of the device. Class I devices present the lowest potential risk and do not require a licence. Class II devices require the manufacturerâ€™s declaration of device safety and effectiveness, whereas Class III and IV devices present a greater potential risk and are subject to in-depth scrutiny. . A guidance document for device classification is published by Heath Canada .
Canadian classes of medical devices generally correspond to the European Council Directive 93/42/EEC (MDD) devices as follows: Class IV (Canada) generally corresponds to Class III (ECD), Class III (Canada) generally corresponds to Class IIb (ECD), Class II (Canada) generally corresponds to Class IIa (ECD), and Class I (Canada) generally corresponds to Class I (ECD) . Examples are surgical instruments (Class I); contact lenses, ultrasound scanners (Class II); orthopedic implants, hemodialysis machines (Class III); and cardiac pacemakers (Class IV) .
 United States
The Food and Drug Administration has recognized three classes of medical devices based on the level of control necessary to assure the safety and effectiveness of the device. The classification procedures are described in the Code of Federal Regulations, Title 21, part 860 (usually known as 21 CFR 860).
 Class I: General controls
Class I devices present minimal potential for harm to the user and are often simpler in design than Class II or Class III devices. These devices are subject only to general controls. General controls cover such issues as manufacturer registration with the FDA, good manufacturing techniques, proper branding and labeling, notification of the FDA before marketing the device, and general reporting procedures. (Most Class I devices are exempt from the good manufacturing practices and/or the FDA notification regulations.) These controls are deemed sufficient to provide reasonable assurance of the safety and effectiveness of the device; or the device is not life-supporting or life-sustaining and does not present a reasonable source of injury through normal usage. Devices in this category include tongue depressors, bedpans, elastic bandages, most hand-held dental instruments, examination gloves, and hand-held surgical instruments and other similar types of common equipment. Depending on the "stated/purported use" of a device, it may be necessary to obtain a Premarket Approval or 510K for the device, which is otherwise classifiable as a Class 1 device. Such devices are referred to as "reserved devices". The electrically-powered arthroscope (which is really an endoscope powered electrically) is a case in point. While endoscopes are Class 1 devices, the electrically-powered arthroscopes need a pre-market notification (510K) although the manual arthroscopes do not. Pre-market notified devices are marketed as "at least as safe and effective, that is, substantially equivalent, to a legally marketed device."
 Class II: General controls with special controls
Class II devices are those for which general controls alone are insufficient to assure safety and effectiveness, and additional existing methods are available to provide such assurances. Therefore, Class II devices are also subject to special controls in addition to the general controls of Class I devices. Special controls may include special labeling requirements, mandatory performance standards, and postmarket surveillance. Devices in Class II are held to a higher level of assurance than Class I devices, and are designed to perform as indicated without causing injury or harm to patient or user. Devices in this class are typically non-invasive and include: x-ray machines, PACS, powered wheelchairs, infusion pumps, surgical drapes, surgical needles and suture material, acupuncture needles.
 Class III: general controls and premarket approval
A Class III device is one for which insufficient information exists to assure safety and effectiveness solely through the general or special controls sufficient for Class I or Class II devices. Such a device needs premarket approval, a scientific review to ensure the device's safety and effectiveness, in addition to the general controls of Class I. Class III devices are described as those for which "insufficient information exists to determine that general controls are sufficient to provide reasonable assurance of its safety and effectiveness or that application of special controls ... would provide such assurance and if, in addition, the device is life-supporting or life-sustaining, or for a use which is of substantial importance in preventing impairment of human health, or if the device presents a potential unreasonable risk of illness or injury."
Examples of Class III devices which require a premarket approval include replacement heart valves, silicone gel-filled breast implants, implanted cerebral stimulators, implantable pacemaker pulse generators and endosseous (intra-bone) implants (with the exception of root-form endosseous dental implants which were recently reclassified as Class II).
 European Union (EU) and European Free Trade Association (EFTA)
The classification of medical devices in the European Union is outlined in Annex IX of the Council Directive 93/42/EEC. There are basically four classes, ranging from low risk to high risk.
- Class I (including Is & Im)
- Class IIa
- Class IIb
- Class III
The authorization of medical devices is guaranteed by a Declaration of Conformity. This declaration is issued by the manufacturer itself, but for products in Class Is, Im, IIa, IIb or III, it must be verified by a Certificate of Conformity issued by a Notified Body. A Notified Body is a public or private organisation that has been accredited to validate the compliance of the device to the European Directive. Medical devices that pertain to class I (on condition they do not need to be sterilised or are not used to measure a function) can be put on the market purely by self-certification.
The European classification depends on rules that involve the medical device's duration of body contact, its invasive character, its use of an energy source, its effect on the central circulation or nervous system, its diagnostic impact or its incorporation of a medicinal product.
Certified medical devices should have the CE mark on the packaging, insert leaflets, etc.. These packagings should also show harmonised pictograms and EN standardised logos to indicate essential features such as instructions for use, expiry date, manufacturer, sterile, don't reuse, etc.
 Radio-frequency identification
 Medical devices incorporating RFID
In 2004, the FDA authorized marketing of two different types of medical devices that incorporate radio-frequency identification, or RFID. The first type is the SurgiChip tag, an external surgical marker that is intended to minimize the likelihood of wrong-site, wrong-procedure and wrong-patient surgeries. The tag consists of a label with passive transponder, along with a printer, an encoder and a RFID reader. The tag is labeled and encoded with the patient's name and the details of the planned surgery, and then placed in the patient's chart. On the day of surgery, the adhesive-backed tag is placed on the patient's body near the surgical site. In the operating room the tag is scanned and the information is verified with the patient's chart. Just before surgery, the tag is removed and placed back in the chart.
The second type of RFID medical device is the implantable radiofrequency transponder system for patient identification and health information. One example of this type of medical device is the VeriChip, which includes a passive implanted transponder, inserter and scanner. The chip stores a unique electronic identification code that can be used to access patient identification and corresponding health information in a database. The chip itself does not store health information or a patient's name.
 Practical and information security considerations
Companies developing RFID-containing medical devices must consider product development issues common to other medical devices that come into contact with the body, are implanted in the body, or use computer software. For example, as part of product development, a company must implement controls and conduct testing on issues such as product performance, sterility, adverse tissue reactions, migration of the implanted transponder, electromagnetic interference, and software validation.
Medical devices that use RFID technology to store, access, and/or transfer patient information also raise significant issues regarding information security. The FDA defines "information security" as the process of preventing the modification, misuse or denial of use, or the unauthorized use of that information. At its core, this means ensuring the privacy of patient information.
 Four components of information security
The FDA has recommended that a company's specifications for implantable RFID-containing medical devices address the following four components of information security: confidentiality, integrity, availability and accountability (CIAA).
- Confidentiality means data and information are disclosed only to authorized persons, entities and processes at authorized times and in the authorized manner. This ensures that no unauthorized users have access to the information.
- Integrity means data and information are accurate and complete, and the accuracy and completeness are preserved. This ensures that the information is correct and has not been improperly modified.
- Availability means data, information and information systems are accessible and usable on a timely basis in the required manner. This ensures that the information will be available when needed.
- Accountability is the application of identification and authentication to ensure that the prescribed access process is followed by an authorized user.
Although the FDA made these recommendations in the context of implantable RFID-containing medical devices, these principles are relevant to all uses of RFID in connection with pharmaceuticals and medical devices.
 List of medical devices
 High-risk devices
High-risk devices are life supports, critical monitoring, energy emitting and other devices whose failure or misuse is reasonably likely to seriously injure patient or staff. Examples include:
- Anesthesia units
- Anesthesia ventilators
- Apnea monitors
- Argon enhanced coagulation units
- Auto transfusion units
- Cardiac defibrillator, external or internal
- Electrosurgical units
- External pacemaker
- Fetal monitors
- Heart-lung machine
- Infusion pump
- Invasive blood pressure units
- Pulse oximeters
- Radiation-therapy machines
An example of the stent used in an EVAR procedure
 Medium-risk devices
These are devices including many diagnostic instruments whose misuse, failure or absence (e.g. out of service) with no replacement available would have a significant impact on patient care, but would not be likely to cause direct serious injury. Examples include:
- Ultrasound sensors
- Phototherapy units
- Human-implantable RFID chips
- Surgical drill and saws
- Laparoscopic insufflators
- radiant warmers (adult)
- Zoophagous agents (e.g., medicinal leeches; medicinal maggots)
- Lytic bacteriophages
 Low-risk devices
Devices in this category are those whose failure or misuse is unlikely to result in serious consequences. Examples include:
 Standardization and regulatory concerns
The ISO standards for medical devices are covered by ICS 11.100.20 and 11.040.01 , . The quality and risk management regarding the topic for regulatory purposes is convened by ISO 13485 and ISO 14971. Further standards are IEC 60601-1, for electrical devices (mains-powered as well as battery powered) and IEC 62304 for medical software. The US FDA also published a series of guidances for industry regarding this topic against 21 CFR Subchapter Hâ€”Medical Devices.
 Packaging standards
Medical device packaging is highly regulated. Often medical devices and products are sterilized in the package. The sterility must be maintained throughout distribution to allow immediate use by physicians. A series of special packaging tests is used to measure the ability of the package to maintain sterility. Relevant standards include: ASTM D1585- Guide for Integrity Testing of Porous Medical Packages, ASTM F2097- Standard Guide for Design and Evaluation of Primary Flexible Packaging for Medical Products , EN 868 Packaging materials and systems for medical devices which are to be sterilized. General requirements and test methods, ISO 11607 Packaging for terminally sterilized medical devices, and others.
 Academic resources
 Industrial resources
 Notes and references
- ^ FDA website: Classify your Medical Device
- ^ FDA Device Classification
- ^ Title 21 Food and Drugs Subchapter-H Medical Devices
 See also
 External links