According to ISO in 14971, a residual risk is the “risk that remains after having adopted measures to take the risk”. But what residual risks are acceptable? This makes many producers of medical devices difficult.

Read here how to arrive at surfing criteria for residual risk. These numbers can be useful to you.

1. Restriscis: the bases

a) Kontext

Medical devices and IVD coverage risks that producers must reduce as much as possible through adequate measures.

b) Resistant single risk compared to total residual risk

If the manufacturer decides not to perform further measures in case of risk, the risk according to the measures adopted corresponds to the risk of individual rest.

Similarly, the total restriction of the product corresponds to the risk after all the measures adopted.

2. Rest of rest: regulatory requirements

a) ISO 14971 requirements

ISO 14971 asks manufacturers to evaluate every single residual risk. This evaluation must be based on the criteria specified in the risk management plan.

Manufacturers are also obliged to ensure that the advantages of the product predominate the overall restriction.

Manufacturers must also decide which residual risks reveals, for example, in an education for use.

After all, the standard requires that residual risks and their acceptance continue to evaluate as long as the products are on the market.

b) MDR

The MDR obliges manufacturers to minimize both the rest and the risk of overall risk:

In order of risk of risk, the management of the risk of manufacturers aims that it is the residual risk associated with each danger and the overall risk is classified as acceptable.

MDR, Anhang I, 4.

The MDR requires two places that reveal the remaining risks in the instructions for use:

Manufacturers teach users any residual risks.

MDR, Anhang I, 4.

The instructions for use contains all the following information:

g) any residual risks, contraindications and all unwanted side effects, including information to be informed of the patient in this context;

Mdr, anhang I, 23.4

3. What residual risks are acceptable?

A detailed contribution to the acceptance of the risk discusses that a risk can be acceptable only if the benefit is higher.

Example 1: residual risk of products with potentially fatal consequences

A radiation device is needed to treat patients with cancer. However, radiation cause damage to radiation that can trigger a new cancer again.

The risk of this potentially fatal radiation -induced disease is acceptable only if the benefit is higher. In particular, the number of deaths that occur with the device must be lower than the number of deaths that occur without the device. “Without a device” does not mean that patients are not treated at all, but with the best alternative, for example another radiation device, chemotherapy, an operation, etc.

These alternatives represent the state of the art.

Example 2: residual risk of products without potentially fatal consequences

This topic does not apply to medical devices that cannot be life. An example would be a treadmill for rehabilitation. In the best case, the product can help patients return to their feet faster after a disease or accident – in the most true sense of the word.

However, these products can cause patients:

• The patient falls, for example because the treadmill blocks and hits with his head on the floor.
• The isolation of a cable breaks, so the mains voltage is directly on the housing and the patient undergoes an electric shock.

To consider if a residual risk is acceptable, the comparison of the number of deaths no longer applies as in the first example. What to do?

Possible risk acceptance criteria

In order to decide whether a residual risk is acceptable, the following types are offered for criteria:

1. Direct comparison of the benefit and risks product and the best alternative, for example based on
   1. Number of deaths
   2. Number of accidents
   3. life
2. Avant -garde: In the second example, the residual risk would be accepted by an electric shock if electrical safety corresponds to the state of the art. In concrete terms, when the medical device was developed and produced according to IEC 60601-1.
3. Comparison with the rules of the risks of life: In other sectors such as the aviation industry, the risks with those of normal life are compared. Only if the latter risks are significantly higher (for example at least a size) is it a residual risk assessed as acceptable.

3. Tips to face residual risks

The following figures can be useful if it is necessary to decide the acceptance of a residual risk:

• About 500,000 infections (for example wound infections after operations) occur every year in German hospitals [Quelle: Charité]. Doctors say that a medical device should not cause any death can indicate that between 80,000 and 180,000 infections could be avoided [Quelle].
• 3000 patients die every year in hospital from MRSA infections, a third of this would be avoidable [Quelle]. The probability of dying from such a germ is therefore about a thousand.
• ISO 13849-1 requires that the users of the machine can be exposed to an event with a serious sequence compared to every 10th working hours.
• The probability of being killed by a car accident is about 2x10e-7 for driving lesson or 2.7 deaths for billions of personal kilometers [Quelle].
• The minimum mortality rate recorded has girls of about 15 years: 3.5E-8/h [Quelle S. 130. Lesenswert ist das Kapitel 5.2]

These numbers help you compare the residual risk with the risks of normal life or risks to the hospital.

4. Conclusion and summary

Manufacturers must determine the individual recovery and the overall risk of rest of each product and evaluate them on acceptance based on previously defined criteria. Whether you reach this obligation, regularly controls the authorities and bodies appointed for admission, audit and inspections procedures.

Change the story

• 2025-05-07: Article largely rewritten
• 2015-12-14: the first version of the article published

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