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Improving Patient Outcomes Using a Diabetic Foot Assessment Tool

August 5, 2005

Summary

Diabetes is the most common cause of end-stage renal disease, and the number of renal patients with diabetes-related problems is increasing. Anecdotal evidence from a 27-bed nephrology ward highlighted an increase in diabetic foot complications often leading to amputation. Preventive measures using an assessment tool have been initiated to improve outcomes for renal patients with diabetes. The aim of the tool is to highlight problems or those at risk of developing problems.

Keywords

Diabetes; Foot care and disorders; Patients: outcome

These keywords are based on the subject headings from the British Nursing Index. This article has been subject to double-blind review. For related articles and author guidelines visit our online archive at www.nursing-standard.co.uk and search using the keywords.

THE INCIDENCE of diabetes has increased worldwide (Haire-Joshu 1996). It is estimated that 15 per cent of all patients with diabetes will eventually develop a foot ulcer, and up to 10 per cent of all non-traumatic amputations are performed on patients with diabetes. The loss of a limb remains one of the most feared complications of the condition (Pickup and Williams 1997), as diabetes is the main cause of amputations in people of working age (Department of Health (DH) 2002). Palumbo and Melton (1985) argue that a foot ulcer should be regarded as a serious complication that can result in amputation if left untreated. Ten per cent of non- healing foot ulcers are due to peripheral vascular disease and diabetic peripheral neuropathy (Springett 2002).

Foster (2002) states that many healthcare professionals have not responded to the problems caused by the diabetic foot despite these complications being well documented. Effective foot care can reduce amputations by two thirds (Audit Commission 2000).

Diabetes

Diabetes mellitus is a metabolic disorder in which the body has a deficiency of and/or a resistance to insulin (Jerreat 2003). It is the most common endocrine disorder and is an insidious disease, with the risk of developing it increasing with age. Type 2 diabetes is growing and is most commonly associated with adults over the age of 40 (Shilling 2003). This type of diabetes is six times more common in people of South Asian descent and up to three times more common among those of African and African-Caribbean origin (DH 2002). Developing diabetes at an early age increases the risk of complications. People with type 2 diabetes are as prone as those with type 1 to developing retinopathy, nephropathy and neuropathy (Foster and Edmonds 2001) and cardiovascular disease. The achievement and maintenance of good blood glucose control are believed to reduce the risk of developing long-term complications (MacKinnnon 2001 ).

The National Service Framework for Diabetes (NSF) (DH 2002) aims to reduce the complications associated with diabetes. Targeting foot care at people who are high risk aims to prevent hundreds of amputations each year. The National Institute for Health and Clinical Excellence (NICE 2004) also emphasises the need for preventive measures, such as regular foot screening and health education, that should extend to patients and family members. These documents provide guidelines on the frequency of the assessments required depending on the degree of foot problems and a suggested pathway for referrals for further assessment and treatment.

The cost to the NHS of treating diabetes is significant. MacKinnon (2001 ) reports that there are more hospital bed days for foot problems than for all other diabetic complications. About 5 per cent of NHS resources and up to 10 per cent of hospital inpatient resources are liable to be used for the care of patients with diabetes (DH 2002). The breakdown of treating diabetic foot disease relates to the individual treatment required. Significant costs relate to high bed occupancy, the cost of vascular surgery and artificial limbs (King’s Fund 1996). This emphasises the need for early detection and treatment of complications to reduce costs and mortality. A large vascular unit serving a population of 500,000 people will expect to see 1OO vascular diabetic patients per year, who will undergo amputation of a limb (Vascular Surgical Society of Great Britain and Ireland 2003 ). The rate of lower-limb amputation in diabetic patients with end-stage renal disease is ten times greater than in the general population of patients with diabetes (Markeia/2003).

Pathophysiology

Patients with diabetes are more likely to develop arteriosclerosis and its progression is more rapid than in patients without diabetes. Arteriosclerosis occurs most frequently in the vessels located between the knee and the foot, with occlusive microvascular lesions occurring in thefeet(Caputoeia/1994).

Foot ulceration can also develop due to the complication of diabetic peripheral neuropathy (Figure 1 ), as well as a compromised arterial blood supply. Diabetic peripheral neuropathy can involve the loss of protective sensation and, therefore, decreased ability to feel pain from injuries affecting the foot (Bryant 1995). Patients can also experience a variety of painful symptoms which are difficult to control, such as burning, sharp shooting pains and paraesthesia in their feet. Foster and Edmonds (2001) add that patients with diabetic peripheral neuropathy develop dry skin with callus and fissures that can lead to ulceration. The compromised arterial supply and effect of diabetes on the immune system mean that patients also have a reduced inflammatory response to heal wounds and overcome infection (Shilling2003).

High blood glucose increases the osmotic pressure of blood, which causes excessive fluid loss from the tissues and an increase in renal function (Chalmers2002). The blood volume decreases because of the excessive loss of fluid, which causes the blood to become thicker (higher concentration of red blood cells), and leads to poor blood circulation, therefore impeding wound healing (Dunning 2003).

Foot complications have been found to be more prevalent in patients with long-term diabetes and end-stage renal disease than in patients with diabetes alone (Hill et al 1996, Mark et al 2003). Neil et al (2003) state that this is often due to:

* Severe hypertension.

FIGURE 1

Gangrenous foot ulceration caused by diabetic neuropathy

* Previous exposure to steroids.

* Altered calcium metabolism.

* Protein restriction.

One of the most common causes of end-stage renal disease is diabetic nephropathy, resulting from microangiopathy, which damages the capillaries that supply the glomeruli (Carr 2003). Extensive atherosclerotic vascular disease is also commonly seen in this group of patients (Hill et al 1996). This may also account for complications such as retinopathy progressing more rapidly with the onset of renal failure (Haire-Joshul996).

Anecdotal evidence from a 27-bed nephrology ward in a district general hospital showed a substantial increase in the number of patients with diabetes and end-stage renal disease, who were admitted over a period of two years. Some of these patients had diabetic foot complications that led to amputation, or developed complications while they were inpatients. This evidence raised the question of the effectiveness of the foot care this group of patients received during their stay in hospital. Nurses are constantly aware of the need to provide a high standard of care and to evaluate the care being given. Parahoo (1997) suggests that the primary goal of nursing is to improve the quality of care for patients. It was recognised that a formal assessment tool and referral strategy needed to be devised to address this problem.

Assessment tools

An extensive literature search emphasised the importance of foot assessment in patients with diabetes. It identified which categories a form should contain for a full assessment and that none of the current tools available could be easily applied to this patient group in the ward environment. Farndon et al (2001 ) suggest that many assessment tools are unsuitable for use in different areas as the content and design make them specific to a particular area. Many of the tools available were too complicated which emphasised the need for the form to be simple to maintain consistent documentation and communication between the different healthcare professionals who care for this patient group (Richbourg 1998). MacDonald (1995) states that tools need to be reliable no matter who the assessor is and be true to purpose: to aid recognition of a problem and initiate or trigger appropriate referral with an indication of the nature of urgency.

The authors’ aim was to design a simple and effective tool, to record details of the foot assessment as part of the hospital admission process, and provide enough information to establish an individual degree of risk. This would then enable referral to an appropriate medical practitioner for more detailed assessment or treatment. Kelechi and Lukacs (1996) emphasise that documentation of findings and interventions is paramount in determining patient outcomes.

FIGURE 2

Dorsal and plantar foot templates

A multidisciplinary team, comprising the nephrology ward sister, vascular nurse specialist, podiatrist and diabetes nurse specialist, undertook the design. Holland etal (2000) advocate a multidisciplinary approach as it improves ou\tcomes for patients.

The tool design contains the benchmarks advocated by Foster and Edmonds (2001):

* Neuropathy.

* Ischaemia.

* Ulceration.

* Infection and necrosis.

Morison (1991) states that use of a wound assessment chart can enable accurate observation of a wound. Taking this into account, to be able to effectively show the extent and position of any ulceration, neuropathy and general skin condition, foot templates showing both dorsal and plantar aspects were included in the assessment tool (Figure 2). By including these, the feet can be reassessed at regular intervals and any further changes recorded on the same tool for evaluation purposes. It was felt that the inclusion of this section would make evaluation more accurate (Knowles and Jackson 1997). Any member of the team would be able to pick up the tool and easily identify vulnerable areas, individual degree of risk and what treatment pathway the patient should be following. The tool can also be photocopied and forwarded to podiatrists and district nurses for further assessment or treatment. The original record should be kept in the patient’s hospital notes so that it can be used as a point of reference if the patient is readmitted.

FIGURE 3

Diabetic heel ulcer

FIGURE 4

Infected diabetic foot ulcer caused by peripheral vascular disease

The assessment of neuropathy is undertaken by using a monofilament pen, which is a reliable means of identifying the degree of risk with loss of sensation and those more at risk of developing a problem (Booth 2000). In addition to testing the prime sites where neuropathic ulceration develops, which are indicated on the plantar foot template, in the absence of evidence of best practice and continuing controversy about neuropathy testing, we chose to test the heel as well. This was included as many of the renal patients have swollen legs and reduced mobility and are therefore at increased risk of developing pressure ulcers on the heels (Figure 3) (Foster and Edmonds 2001 ). The results are recorded directly on the tool and the presence of neuropathy is shaded to show the extent of the loss of sensation. Neuropathy may conceal any foot or leg pain so it is important that other signs and symptoms are assessed (Shilling 2003), such as assessing the foot for signs of dry skin, clawing of the toes, distended veins on the dorsum and plantar callus formation (Santos and Carline 2000).

Documentation

Circulation assessment findings are documented directly onto the form by noting the presence of pedal pulses and the temperature of the feet. Pulse palpation is fallible; pedal pulses are often absent in the presence of arterial disease and nurses may mistake their own pulse for that of patients (Cantwell-Gab 1996). Assessment of arterial flow is by a handheld Doppler ultrasound (Foster and Edmonds 2001 ). This provides the ability to examine and compare arterial blood flow only in both legs. The incidence of peripheral vascular disease (Figure 4) is increased in patients with diabetes (Williams and Pickup 1999). Diabetes increases calcification of arteries, which can change the sound of the arterial flow from a normal triphasic, three-sound signal to a monophasic, one-sound signal indicating vessel abnormality. Peripheral flow may be normal or abnormal with extensive calcification (Edmonds and Foster 1992).

The waveform in Figure 5 demonstrates the triphasic shape where there are three phases of blood flow: strong forward flow in systole, transient reverse flow in early diastole, and weak forward flow in late diastole. This pattern is evident in an artery free of occlusive disease.

The pattern in Figure 6 shows a monophasic waveform, which occurs with progressive arterial disease. The systolic rise is slower, there is reduced peak velocity, loss of early diastolic reversal and a more rounded dampened waveform (Vowden 1997). This is a continuous sound with no evidence of pulsation. It is often not a clear sound, which corresponds with the disease within the artery and the reduced velocity of blood flow.

FIGURE 5

Triphasic waveform

FIGURE 6

Monophasic waveform

The recording of the ankle brachial pressure index (ABPI) is complicated by calcification but can provide a good indication of the presence of ischaemia in the lower limbs (Santos and Carline 2000). The ABPI in an artery free of disease is usually higher or equal to the brachial systolic pressure. The results can be falsely elevated in patients with diabetes and renal disease due to calcification of the arteries, resulting in inability to compress the artery and should be interpreted with caution.

Baker and Raynan (1999) suggest that it is essential for practitioners to have a clear understanding of the anatomy and physiology involved in interpretation of Doppler assessment results, along with interpretation of the sound of the arterial flow for the information to be clinically relevant. They conclude that Doppler waveforms can provide good data, support diagnosis and indicate any degree of arterial insufficiency. This was considered especially important in the classification of the individual degree of risk. A noticeable difference in the warmth of the limb could be consistent with an inflammatory response or coldness could represent ischaemia. Colour and temperature of the skin indicate reduced blood flow through the foot (Silhi 1998).

The individual level of risk is the collective results of the foot assessment and risk assessment with classification of the overall risk rating. Classification of the foot problem is essential (Foster 2002). The authors’ classification or grading for end-stage renal disease is based on a combination of the simple staging system and the Wagner (1979) system, and the focus on feet categorisation (Harman 1998). This combination covered all the knowledge levels of nurses caring for patients to allow for identification of a problem and prompt referral for further assessment or treatment. The aim was to highlight a problem or those at risk of developing problems, not to diagnose the problem.

Sensitivity and specificity indicate the validity of a tool (MacDonald 1995). This tool has sensitivity as it is able to identify those ‘at risk’. The measure here is patients who went on to develop foot complications. Specificity is represented by the ability of the tool to identify patients who are not at risk and who do not develop any foot complications.

Introduction of the tool

Before the tool could be implemented, the ward staff required training by the vascular nurse and nephrology ward sister. Nurses are expanding their practice and undertaking roles previously done by other medical practitioners. For example, detailed foot assessments using a monofilament pen are not routine practice by general nurses but are usually undertaken in a specialised foot clinic by either podiatrists or chiropodists. Changes in practice are usually undertaken to meet the demands of everchanging healthcare needs (Kelechi and Lukacs 1996). Neilei al (2003) state that nephrology nurses who are experts in the assessment and application of haemodynamic principles related to renal failure may know little about foot ulcer prevention. This highlighted an educational issue for the ward staff to understand why people with diabetes develop ulceration and the importance of a detailed foot assessment.

The implementation of the change involved careful planning. Those involved needed to be educated, and its success was dependent on how clearly the idea was explained (Massie 1998). Three months were set aside to train all staff in use of the tool, the monofilament pen and Doppler ultrasound equipment. Nurses are required to meet certain standards to undertake specific skills, which should be practised and maintained to ensure patient safety ( Anderson 2003 ).

Standards were set relating to the use of the Doppler ultrasound equipment and monofilament pen, as this equipment was new to the ward staff. The aim was to demonstrate competence in use of the equipment while undertaking the assessment, interpretation of the results and knowing how these results may be affected by diabetes, renal disease and foot problems such as calluses and which treatment the patient should then receive (Anderson 2003). The authors felt a six-monthly review of skills was adequate to maintain standards and competency. Along with the design of the tool this will help to meet clinical governance objectives by providing clear written evidence for the documentation of care (Swage 2000).

The implementation of the tool and suggested referral pathway highlighted a deficit in the podiatry service for inpatients requiring attention. Patients are routinely seen as outpatients, at intervals depending on the condition of their feet. All patients with no evidence of ulceration or neuropathy are reviewed yearly. Those with foot complications are seen more frequently. The NSF (DH 2002) suggests that patients classified as at increased risk of ulceration should be seen three to six monthly, and those people at high risk between one and three monthly.

In a study in Scotland, Mark et al (2003) highlighted similar problems for renal patients with diabetes. They advocated a multidisciplinary approach to care and suggested that there may be a place for podiatry services within renal clinics. This might be a possible solution to the authors’ situation, as the service problem we highlighted is currently under review as a result of the increase in requests for inpatient review.

Audit

An audit was undertaken after the tool had been used for six months. A questionnaire was given to all staff to determine how user friendly the documentation was and if it had made any difference to the care of this patient group. The results were some minor changes in the layout and the need for additional patient information. A crib sheet was designed to assist staff when carrying out the assessment.

During the six-mont\h period 50 patients were assessed (Table 1). Table 1 shows the total number of patient foot assessments that were undertaken over this six-month period. It identifies the individual degree of risk categories that the patients assessed fell into.

TABLE 1

Foot assessment results

TABLE 2

Retrospective data

Seven of the very high risk group had already had an amputation. Two other patients in the very high risk group were admitted with existing problems, which resulted in amputation. Only 19 forms (n=43,44percent) indicated that patients were currently receiving any form of podiatry care and follow up by diabetes nurses in the community. Twenty two forms (n=43,51 per cent) did not have this information completed, which highlighted the importance of obtaining this information to arrange follow-up care and continued health education.

Table 2 indicates retrospective data from the renal ward over the previous two years, based on all those who had undergone a limb amputation during that time. This shows that there were a total of 18 amputations in that time, with six patients developing a problem that resulted in amputation during their stay.

Conclusion

The implementation of this assessment tool has increased knowledge and understanding of the importance of carrying out an early assessment to prevent foot complications in this growing patient population. Neil et al (2003) state that if nephrology nurses are to prevent foot complications occurring they need to carry out early assessments to enable them to commence preventive strategies. The authors’ current practice supports this. Potential foot problems are being recognised earlier, and there is now a recognised referral strategy in place, which can be used by any member of the multidisciplinary team. This supports work undertaken by Massie (1998), who states that screening tests are useful ‘where there is an important health problem that can be improved by early detection using a simple, convenient and reliable low-cost effective tool’. Its benefit and success can be measured by its use in other ward settings.

The use of this tool has introduced evidence-based practice into the ward environment and enhanced the care of patients with end- stage renal disease, diabetes and related foot problems. The documentation has been adopted for use in the haemodialysis units, continuous ambulatory peritoneal dialysis units and will soon be introduced into the low clearance clinic. The assessment tool is being considered for use across the trust for all inpatients with diabetes who are at risk of developing problems.

Without the driving force of the nurses this project would not have been successful. Their interest and recognition of the need to improve their knowledge and skills for the benefit of patients has resulted in the delivery of more effective and efficient care. The project has been underway for 20 months and during that time there have only been two amputations – these were performed on patients admitted with complications that were not developed during their stay. This initiative has improved the quality of life for renal patients who experience diabetic complications, and locally is helping to meet the standards set by the NSF (DH 2002) to reduce the number of amputations. This tool has enabled nurses to improve the care and quality of life for renal patients with diabetes

Evans J, Chance T (2005) Improving patient outcomes using a diabetic foot assessment tool. Nursing Standard. 19, 45, 65-77. Date of acceptance: December 2 2004.

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Authors

Julie Evans is ward sister; Tina Chance is vascular nurse specialist, Kent and Canterbury Hospital, Canterbury, Kent. Email: julie.evans@ekht.nhs.uk

Copyright RCN Publishing Company Ltd. Jul 20-Jul 26, 2005




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