Pressure ulcer: Assessment and prevention (part 2)

Dr.Almoutaz Alkhier Ahmed
Saudi Arabia / Gurayat north
Diabetic center
E.mail: khier2@ yahoo.com

In this part I will continue discussing the issue of prevention of pressure ulcers and risk assessment tools. This part will also cover the possible interventions, which can be applied to prevent pressure ulcers.

RISK ASSESSMENT TOOLS IN A PROGRAM OF PREVENTION OF PRESSURE ULCERS:

The risk assessment tools measure broad categories of factors that most commonly put patients at risk and that can be committed to interval ratings.

There is evidence that a prevention program guided by risk assessment can simultaneously reduce the institutional incidence of pressure ulcers by as much as 60% while reducing the cost effect.⁽¹⁾

The key of success is through a multidiscipline team approach. The two major team participants are nurses and occupational therapists.

Nurses are responsible for primary risk assessment while occupational therapists offer special skills help in identification of special risks related to setting surfaces, instruction in pressure relief and prescription of positioning devices and wheelchair settings.

In applying preventive programs for pressure ulcer, it is important to choose a risk assessment tool. These tools vary from simple to complex. The US Preventive Services Task Force recommends certain criteria in qualitatively evaluating the appropriateness of screening tests.⁽²⁾ The first criterion is related to the effectiveness of the treatment for the condition predicted and the second relates to the burdens of suffering in terms of mortality, morbidity, discomfort, dissatisfaction or destitution.

The paper and pencil rating scales possess the best balance of characteristics.
The more complex tools such as Laser Doppler flowmetry have higher costs, lack simplicity and practicality of use, and are less accurate predictors than the paper and pencil rating scales.

Two ratings scales have been recommended by the Agency for Health Research and Quality (AHRQ) panel in its pressure ulcer prevention guidelines.⁽³⁾

The first one is the Norton Scale⁽⁴⁾:
It is reported to have good sensitivity but low to moderate specificity at a score of 14 (Norton scale has a range between 5- 20).⁽⁵⁾

The second one is the Braden Scale⁽⁶⁾:
It has demonstrated good sensitivity and specificity in a variety of settings at cutoff scores that range from 16-18.

The Braden scale has also been demonstrated to have excellent inter rater reliability when used by registered nurses but a lower level of reliability when used by licensed practitioner nurses or nursing assistants.⁽⁷⁾

Clinicians should keep in mind that the risk assessment tools will support their clinical judgment, not replace it. Additional factors should be considered when assessing for risk of pressure ulcer development.

Such factors as the age of the patients could affect the development of ulcer even if the patient's score was high.

Some of the risk factors that have been able to predict who develops pressure ulcers and who does not are advanced age, low diastolic pressure, elevated body temperature and inadequate current intake of protein.⁽⁸⁾

PREVENTIVE INTERVENTIONS

Preventive interventions should become more frequent for those who are at greatest risk of developing pressure ulcer. A good understanding of pressure points will help the health provider to choose the most appropriate intervention suitable for their patients (Figure 1).

Figure 1: Pressure points for bid ridden patient

Supine position
1. occiput
2. scalpula
3.sacrum
4. heels

Lateral position
1.ear
2. acromion process
3. elbow
4. trochanter
5. medial & lateral condyle
6. medial and lateral malleolus
7. heels

Prone position
1. elbow
2. ear, cheekm nose
3. breasts (female)
4. genitalia (male)
5. iliac crest
6. patella
7. toes

Figure 2: Chair fast pressure point

Braden and Bergstorm,⁽⁹⁾ have made specific recommendations based on level of risk. They classified the risk level into 4 levels (mild, moderate, high and very high) and they specify recommendations for each level.

There is evidence that this approach leads to more effective and less expensive care.⁽¹⁰⁾
Following certain programs will allow clinicians to direct their attention to the highest risk group and concentrate their efforts to prevent the occurrence of pressure ulcers on them and neutralizing the risk factors.

The following preventive interventions are aimed at reducing the intensity and duration of pressure in both bedfast and chairfast patients:

1) Turning schedule:
Bedfast: Close attention should be paid to an individualized turning schedules. These schedules can be altered to meet the patient's needs. Repositioning should be done with assistance and with attention to good mechanics such as using pillows to protect bony prominences. When using pillows to protect heels, the heels must be checked frequently to ensure that as the pillows compress, they remain free of pressure. If pillows are not effective in protecting the heels, consult with a physical therapist or occupational therapist to construct devices that adequately protect the heels from excessive pressure. The pressure-releasing ankle foot orthoses are often used to prevent pressure on the heel. At higher levels of risk or for emaciated patients, turning schedules should include either increased frequency of turns or assisted frequent, small shifts in body weight. Lateral turns should not exceed 30 degrees.⁽¹¹⁾ Foam wedges are helpful in lateral positioning and can be used to increase the frequency of repositioning by putting it out slightly every 30 minutes to 1 hour. If sedation or narcotics are being used extra attention should b e paid to turning those during heavy sedation. Patients can be positioned in the prone position for complete pressure relief over the heels, trochanter and sacral regions. This position is contraindicated in patients who have a gastrointestinal tube or nasogastric tube, due to high probability of regurgitation. In patients with partial or complete paralysis of the diaphragm or trunk, the prone position may impair respiration.

Chairfast: Great attention must also be paid to effective chair positioning as very high interface pressure and shearing forces can develop with poor posture or seating surfaces.
Interestingly, Defloor and Grypdonck had described chair positioning aimed to decrease pressure ulcers.⁽¹⁶⁾

2) Remobilization of the immobile:
During the illness, some patients may become less mobile or even immobile. The nurse should be alert to this. During an episode of illness, it is expected for elderly persons to be less active than is optimal and to enter into a spiral of deconditioning and decline. Physical therapy consultation may be helpful in determining the degree to which remobilization is possible and beginning the process of remobilization. Collaboration between the team and the patient is mandatory to achieve good results. In cases for which the return to full mobility is not possible, the patient can be taught to make small shifts in body position such as moving the legs and shifting weight from one buttock to another.

If the patient is wheelchair bound, he or she needs to be taught to perform a variation of push- ups. This should be done while the wheelchair is locked; the armrests are locked to the wheelchair, the patient grasps the armrest with respective right and left hands and pushes down on the armrest. This should be performed every 15 minutes throughout the time spent in the wheelchair.⁽¹²⁾ Patients could also do lateral weight shifts but this requires good balance and strength. Also, forward weight shifts or rises may be performed but also need good balancing and strength. To increase patient's adherence to pressure relief maneuvers a reminder for the scheduled times to do this, such as an auditory cue e.g. an alarm wrist watch, may be an effective reminder to perform pressure relief.

3) Use of special support surfaces:
Support surfaces include overlays (mattress or wheelchair seating), mattress replacements or specialty beds. Mattress overlays and mattress replacements may be classified as either static (e.g. foam, gels) or dynamic (e.g., alternating pressure surfaces). Specialty beds are classified as either low-air-loss or air fluidized.

Whittemore⁽¹³⁾ and Reddy et al (14) did two excellent integrated reviews of existing research related to the efficacy of various pressure reduction surfaces.

In my opinion, the systematic review done by Reddy et al is so comprehensive and informative, although they reached a conclusion that there is a need for well-designed RCTs that follow standard criteria for reporting non-pharmacological interventions and that provide data on cost-effectiveness for these interventions, but it contained a lot of information that can be beneficial for readers.

Patient situation is the real guide for suitable options to his/her condition. If the patient is bed-bound, an overlay or replacement support surface, to decrease interface pressure over bony prominences is recommended.⁽¹⁵⁾ If the Braden scale is below 7 or the patient has intractable or severe pain exacerbated by turning, use of low air loss beds may be indicated. Terminal patients need not have a rigorous schedule of turning. Comfort is the goal for them.

A patient who is chair bound also needs special subset surfaces. Defloor and Grypdenk (16) compared 4 surfaces (2 static air, 1 foam and a water cushion). They found that the static air cushions provided the best pressure reduction.

The type of wheelchair back and cushion will depend on the need of sensation and ability to perform pressure relief. Cushions are selected based on their ability to provide pressure relief and prevent pressure ulcers. Other considerations include weight, height, contour, shape, size, and stability versus emersion, composition of materials, cover materials, maintenance and cost.⁽¹⁷⁾ The most common prescribed cushions are gel, air, flotation or a combination of different shapes and materials.

Assessment used to determine pressure ulcer risk assessment with seat cushions may also be used for seat backs.

4) Managing moisture:
Exposure of the skin to extensive moisture from any source can weaken the outer layers and increase the opportunity for skin injury.

Incontinence: it is a common cause of skin maceration and breakdown. Multiple options are available to clinicians such as bladder training, promoted voiding or behavioral methods.^(18,19) If the nurse decides to use a moisture barrier after each incontinent episode, the nurse should use a very mild soap to cleanse the skin, rinse thoroughly and pat the skin dry.

Absorbent underpads or briefs should be used and checked frequently and changed as needed. The use of thin, plastic-backed underpads should be avoided, as these keep the mattress dry while the patient sits in a pool of urine or liquid stool.

Diarrhoea: it is very caustic to skin and can lead quickly to skin breakdown. If intervention to stop diarrhoea does not bring quick results, a fecal incontinence pouch should be used while further attempts at control are made.

Perspiration: it can be problematic when it is constant, trapped between skin folds or held close to the skin through contact with non-breathable support surfaces. Use of absorbent powders is generally not advisable as the powder may collect in skin folds and become a source of injury.

5) Friction and shear:
Both are very harmful to the skin and make it susceptible to the effect of pressure.
The findings reported by Dinsdale⁽²⁰⁾ were very amazing for me and answered one of the questions on my mind regarding the pathophysiology of pressure ulcer. The question was: what is the amount of the force needed to develop ulcer in healthy and weak skin.

Dinsdale found that, in the absence of friction, a pressure of 290 mmHg was required to produce ulceration while a pressure of only 45 mmHg would produce ulceration in skin pretreated with friction. Although this experiment was done on swine we can learn the effect of friction.

Interventions that can be used to prevent or ameliorate exposure of the skin to friction and shear are:

• The use of a trapeze or turning sheet.
  
• Ankle and heal protectors
  
• Hydrocolloid dressings may be used over specific prominences being exposed to friction.
  

The sacral area could be a victim of shearing forces while the head of the bed elevated or the patient slumps in a chair.
Interventions decrease the effect of shearing:

• Maintaining the elevation of the head of the bed at or below 30 degrees
  
• Duration of high elevation should be minimized in a person with high risk levels.
  
• Recliner or special chair that allows for backward recline with elevated legs should be considered.⁽⁴⁾

6) Nutritional repletion:
Both long term and short-term problems with nutrition make patients more prone to pressure ulcer development. It appears that an even slightly lower than optimal dietary intake of protein is an especially strong risk factor.⁽²¹⁾

Protein and energy are essential requirements for healing but there is no direct evidence that other elements such as Vit A, Vit C and Zinc are important in building new tissue and healing injured tissue. When there is nutritional problems such as those on parental feeding, nutritional consultation should be done.

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