Blood flow assessment

The PU sensor uses a proprietary method and instrument to assess blood flow in the superficial tissue. The technique is based on Photoplethysmography (PPG), which is a procedure where the skin is illuminated, and the reflected light is measured. This is an established technology that is used in heart rate monitors (HRM watches) and other devices.(t04).

The PUsensor has a sensing unit that is built in to a thin, soft disc that is applied to the back. The device’s proprietary, patent-pending method allows medical professionals to evaluate blood flow with and without the application of the patient’s body weight. The medical instrument works independently, and the method does not require staff monitoring while in use. A built-in algorithm then evaluates the comparative measurements and generates an assessment of the patient’s risk profile based on blood flow.



The ability to better predict which patients are at risk of developing pressure ulcers allows professionals to apply preventative measures with a greater degree of accuracy. This allows care providers in hospitals and care homes to take preventative measures where they are needed most. This offers a host of benefits for the patient, the healthcare sector and society.

Reduced suffering

Individuals who are spared the suffering caused by pressure ulcers have a greatly increased quality of life and avoid the risk of complications caused by pressure ulcers. The duration of care is also reduced, and the individual is able to get back to their regular routines more quickly.

Properly focused care

By reducing the occurrence of pressure ulcers, a patient’s treatment can focus on the illness or injury that gave rise to the need for care in the first place, rather than on new injuries arising during the delivery of care. Greater accuracy in risk assessments allows pressure ulcer prevention methods to be focused on the patients who need them most.

Lower costs

By reducing the occurrence of pressure ulcers, we also reduce the cost of care and costs associated with dressing materials used to treat pressure ulcers. Serious pressure ulcers can give rise to the need for surgery and other costly treatment methods. By reducing the number of pressure ulcers, the number of days that care is needed is reduced, and the individual can get back to their regular routines more quickly. Prevention is always less costly than treatment.


Pressure ulcers

Pressure ulcers afflict people of all ages across the globe and are one of the most common injuries suffered by patients in the course of care. A pressure ulcer is an injury to the skin and/or underlying tissue caused by insufficient blood flow as a result of pressure on the skin, for example, due to extended periods of laying or sitting.  The pressure deprives the cells of the oxygen and nutrients they need. Pressure ulcers are the cause of tremendous suffering, high healthcare costs and can occasionally lead to death. Approximately 15% of all patients in Swedish hospitals are afflicted by pressure ulcers. This results in costs amounting to several billion krona in Sweden alone.

Risk assessment

There are preventative measures that can help. Therefore, patients undergo a risk assessment when admitted to hospitals and care homes according to established methods; usually through the application of assessment scales. Those patients who are assessed to have the greatest risk of developing pressure ulcers are the most likely to be treated using preventative measures.  However, about half of all pressure ulcers in Sweden occur in patients who were not assessed to be in the high risk category. This means that current risk assessment methods are not as reliable as they need to be. It also means that the number of patient’s suffering from pressure ulcers would be lower if we were able to better identify those that fall into the risk group.

PU sensor’s method and technique

Assessment scales are widely used, but these are not very precise since they rely on an assessment of the patient’s condition and are rather subjective. The method and technique our PU sensor uses is based on an assessment of the individual’s physiological status, through an examination of the patient’s superficial blood flow in places where pressure ulcers tend to occur, and the skin is bearing the patient’s body weight.


PU sensor at Medicinteknikdagarna

PU sensor is excited to be an exhibitor at the upcoming Medicinteknikdagarna 2019. This year Medicinteknikdagarna will be held in Linköping on 2-3 October. PU sensor will both have a booth at the exhibition give a short presentation [...]

September 24th, 2019|

PU sensor at the EPUAP-exhibition

PU sensor is attending EPUAP’s exhibition in Lyon, France. The exhibition is visited by top names in the field of pressure ulcer care. That’s why PU sensor is there to inform how we can contribute to preventing pressure [...]

September 19th, 2019|

PU sensor at the EPUAP conference

PU sensor is excited to be an exhibitor at the upcoming EPAUP Pressure Ulcer Prevention Conference.  The conference will be held at Cité Centre de Congrés in Lyon on 18-20 September and is expected to attract thousands of [...]

September 13th, 2019|
Load More Posts



The company, PU sensor AB, was founded in 2016 by researchers Anna-Christina Ek and Margareta Lindgren. The pair have been conducting research on pressure ulcers at Linköping University for a number of years and are currently involved in determining the assessment methods used in care homes and hospitals.

Our Team

PU sensor’s team currently consists of a number of individuals with experience in technology, medicine and business development strategy, while the company has access to an extensive network of contacts within the research community, healthcare and nursing care sectors and measurement technology.

Porträttbild av Johannes Walfridsson




Porträttbild av Tova Persson




Porträttbild av Anna-Christina Ek



Professor em.

Medical & scientific officer

Porträttbild av Margareta Lindgren



Associate Professor

Medical & scientific officer

Porträttbild av Johannes Walfridsson



Development engineer

Porträttbild av Johannes Walfridsson



Development engineer


PU sensor has established partnerships with a number of different actors who complement our business in a variety of ways and strengthen our offerings.


PU sensor’s vision is to make blood flow measurement a widespread, integrated part of the pressure ulcer risk assessment process within the healthcare, nursing and research sectors. In this way, we will promote increased knowledge within the healthcare, nursing and research sectors until pressure ulcers become a thing of the past.


We would be happy to hear from you if you have further questions about PU sensor’s method and the product.(

Johannes Walfridsson


+46738 087 070

Tova Persson

Chief technology officer

+46702 800 825



Teknikringen 7
583 30 Linköping

More information

Would you like to learn more about PU sensor? Fill in your contact information here, and we will get in touch with you!

    Go to Top