What are pressure ulcers?

Pressure ulcers are damages to the skin and/or the underlying tissue as a result of pressure, or pressure in combination with other factors. Most of the time it is the pressure from the person´s own bodyweight against the mattress that causes pressure ulcers. The risk of developing pressure ulcers depends on both how large the pressure is, how long the tissue is subject to pressure and how sensitive an individual is to pressure. Bony prominences are extra sensitive to pressure ulcers since the pressure over them becomes extra large. 

What types of pressure ulcers are there?

Pressure ulcers can have different severity and are categorized as follows:

  • Category 1: Non-blanchable erythema – intact skin with redness. 
  • Category 2: Partial thickness skin loss – superficial open wound or blister.
  • Category 3: Full thickness skin loss – damage through the entire skin layer, down to the subcutaneous fat.
  • Category 4: Full thickness tissue loss – deep injury with exposed bone, tendon or muscle.
  • Unclassified pressure ulcer: depth unknown – full thickness skin loss, but the depth of the skin is covered by dead tissue or eschar.
  • Suspected deep tissue injury: depth unknown – discoloration maroon or purple area with intact skin.

What are bedsores?

Bedsores are an older term for pressure ulcers. Nowadays the term pressure ulcers are used since these ulcers do not only occur when lying down. 

What causes pressure ulcers? 

When the skin is exposed to pressure the tissue is deformed and the blood flow is affected. At a reduced blood flow the cells do not get enough oxygen and nutrients, and waste products are not removed. A person with normal sensory perception and mobility feel discomfort if the blood flow is reduced in parts of the skin and changes their position. If this does not happen, the persistent reduced blood flow will lead to the cells dying and pressure ulcer developing. 

How do you normally assess the risk of pressure ulcer?

Pressure ulcer risk assessment should be done as soon as possible in the beginning of a care period, e.g. on arrival at a hospital or nursing home. An n updated risk assessment should be made in the event of a change in medical condition or medication.

Today´s risk assessment is based on a form (oftem called a scale) with a number of questions that a nurse answers. Common for the forms is that the individual is given points for a number of factors that affect the risk of pressure ulcers, such as activity, mobility, sensory perception and nutrition. The points are then added up and the result determine whether the individual is considered to have an increased risk of pressure ulcers or not. In addition to the scales a clinical assessment is made, which includes examining the skin. It can be difficult to estimate and evaluate the various factors in the forms. Therefore, the results may vary as different people make the assessment, and the precision of the risk assessment is relatively low.

Why is there a need for better methods of pressure ulcer risk assessment?

Today’s methods for pressure ulcer risk assessment are entirely subjective and are only based on external factors in the individual being assessed. Today´s methods do not evaluate what happens physiologically to an individual when the skin is exposed to pressure.

How are pressure ulcers prevented?

In practice, pressure ulcers are mainly prevented by reducing the pressure on the skin. Preventive skin care, meeting and following up on nutrition and fluid intake are other important measures. 

The pressure is often reduced with special mattresses, everything from pressure-distributing foam mattresses to active mattresses with a continuous air flow system. The choice of mattress often depends on the risk of pressure ulcer or if pressure ulcers have already developed. Positioning and frequent changing of position are other ways of reducing the load on the skin. Positioning pads can me used to vary how the individual is lying to relieve specific body parts.  

Preventive skincare aims at keeping the skin dry, soft, and clean. An individual plan is needed for people with incontinence. In some cases, pressure-preventing dressings are used as a complement.

To effectively prevent pressure ulcers, systematic work is required throughout the care chain. Therefore, it is very important with a structured risk assessment to provide the right conditions for the preventive work.

Can pressure ulcers be treated?

The most important measure for treating pressure ulcers is pressure relief where the wound is. Pressure ulcers are treated differently depending on their severity or category, but cleaning and dressing with a suitable dressing is the basic treatment in addition to the pressure relief. In severe cases, antibiotics or surgical treatment may be required.  

When should you use PU sensor?

PU sensor should be used as a complement to the traditional risk assessment. The examination with PU sensor is preferably done in connection to the traditional risk assessment, as soon as possible after arrival at a care facility.

How does an examination with PU sensor work?

An examination is done in four steps:

  1. The patient is positioned lying on their side and the sensor plate is attached to the lower back (sacrum) with a double-sided tape. An inflatable pillow is placed around the sensor plate and the patient is turned on their back.
  2. The examination is started by the user pressing the start button. The process is thereafter automatically controlled by the device.
  3. First the inflatable pillow is inflated to unload the area of the sensor plate, and the sensor plate gathers information on the blood flow in the unloaded skin. Then the inflatable is emptied, and the sensor plate gathers information on the blood flow in the loaded skin. The blood flow in the two phases is compared and PU sensor presents a result of how the blood flow changes with the pressure, and if the response indicates an enhanced risk or not. 
  4. The patient is turned to their side and the sensor plate and inflatable is removed.

Why should you use PU sensor?

An examination with PU sensor adds something thet the traditional risk assessment lacks, namely an evaluation of the superficial blood flow when the skin is exposed to pressure. Since an insufficient blood flow is one of the main causes of pressure ulcers, the skin blood flow is of great importance to the risk of developing pressure ulcers.

How much time does a PU sensor examination take?

An examination with PU sensor normally takes about five minutes.

For whom can PU sensor be used?

PU sensor can be used on everybody that normally would go through a pressure ulcer risk assessment, with the following exceptions:

  • The person cannot lay still on their back.
  • The person has a wound or damage to the skin at the lower back (sacrum) where the sensor plate should be placed.
  • The person has a fever.
  • The person weighs more than 200 kg.
  • The person has a known allergy or sensitivity to any of the silicone or plastic materials that are part of the product.

How does PU sensor work?

PU sensor examines how the superficial blood flow changes when the skin is exposed to the pressure from the person´s own body weight. A healthy response is an increase in blood flow at the pressure from the body weight, but for some people the blood flow decreases instead. It is these individuals with a decreased blood flow that PU sensor can identify as at risk of developing pressure ulcers.

The method is based on sending light into the tissue and detecting the light that comes back. Since the blood absorbs light a pulsating signal corresponding to the blood flow can be captured. The same technique is used in for example pulse watches and pulse oximeters.

Why is the superficial blood flow important?

The superficial blood flow ensures that the skin receives enough oxygen and nutrients, and that waste products are removed. An impaired blood flow at pressure can result in a lack of oxygen and nutrients, and lead to a build-up of waste products in the tissue, which can cause cell death and thereby pressure ulcers. How well the superficial blood flow works is directly connected to the risk of developing pressure ulcers. 

What do I need to know to start using PU sensor?

To use PU sensor, you should have read the user manual that is provided for the product. No additional information is required, but to facilitate the information intake there is a number of instructional videos on the user pages of PU sensor´s web page. 

Can we save money using PU sensor? 

Pressure ulcers cause both great suffering for the people affected and large costs for the care facilities, both in the form of extra work and costs for dressings and other equipment. According to international studies, pressure ulcers account for about 4% of all heath care costs in many countries.

Even though it is hard to estimate the costs for prevention and treatment of pressure ulcers, there is a consensus that it is cheaper to prevent pressure ulcers than to treat them. If the risk assessment would correctly identify a larger amount of the risk patients and make sure they all get adequate prevention, many pressure ulcers could be avoided, and money saved. This is exactly what PU sensor aims to do.