The best-practice document for the management of lymphoedema (Lymphoedema Framework, 2006) recommends measurement of the ankle brachial pressure index (ABPI) prior to the use of compression therapy, while recognising the limitations of ABPI measurement. Further, the Wounds UK (2015) best-practice statement for compression hosiery only supports the application of compression of 14–17 mmHg in the absence of ABPI.Yet this is not reflected in standard practice in specialist lymphoedema clinics (British Lymphology Society (BLS), 2018).
A position paper on ABPI was launched at the BLS annual conference in 2018, with the aim of supporting decision-making for practitioners and enabling instigation of appropriate compression in the absence of an ABPI. The document references a questionnaire study conducted by Todd et al (2008), which showed that 46% of lymphoedema specialists felt that the ABPI was inaccurate in the presence of lower-limb oedema.The BLS also recognised that, in the field of lymphoedema, there are a considerable number of allied healthcare professionals (e.g. physiotherapists) who specialise in lymphoedema for whom ABPI measurement and wound care are not integral to their training.
The position paper clearly states that routine ABPI measurement for patients who present with lymphoedema is not required in the absence of significant cardiovascular risk factors and clinical signs or symptoms of peripheral arterial disease, provided that the patient's vascular status has been thoroughly assessed. If there are concerns in terms of reduced arterial flow, a referral for further vascular assessment and possible intervention should be pursued. Further, documentation and effective communication must be provided to all healthcare professionals involved in the ongoing management of the patient with lymphoedema, highlighting the clinical assessment and rationale for not completing an ABPI measurement. A vascular assessment checklist is included (see Table 1) for ease and to identify when onward referral is necessary.
Although the document has been developed primarily for lymphoedema therapists, the information is directly relevant to other specialties and generalists alike (for example, community nurses) and is freely available on the BLS website (www.thebls. com). While some generalists may still require clear guidelines with which to work, they need the ability to interpret these guidelines based on key theoretical principles and clinical knowledge/expertise, and the position paper facilitates such interpretation.
Ankle brachial pressure index
ABPI assesses the arterial circulation to the lower leg by comparing the blood pressure in the arm with the blood pressure in the ankle (Keen, 2008; Gogalniceanu et al, 2018) (Tables 1 and 2).
| Instruction | |
|---|---|
| 1 | Have the patient lie in the supine position for 15–20 minutes |
| 2 | Apply a blood pressure cuff to the arm |
| 3 | Place a hand-held Doppler probe over the brachial artery, enabling the pulse to be heard. Inflate the cuff until the sound of the pulse stops; then, deflate it slowly until the sound returns, at which point note the systolic pressure. Repeat this on the other arm. Use the higher value from the two arms |
| 4 | Repeat the process on each ankle, with measurements taken from at least two of the four pedal pulses (usually, the dorsalis pedis and posterior tibial pulses) |
| 5 | Calculate the ABPI by dividing the highest systolic measurement of each foot by the highest systolic arm measurement |
| ABPI value | Instruction |
|---|---|
| Less than 0.8 | Compression stockings contraindicated, as severe arterial insufficiency is likely; refer for specialist vascular assessment |
| Between 0.8 and 1.3 | Compression is considered safe |
| Greater than 1.3 | Avoid compression, as high ABPI values may be due to calcified and incompressible arteries; refer for specialist vascular assessment |
NB: An ABPI >0.8 does not necessarily mean that high-compression bandaging can be undertaken safely. Other factors, such as diabetes, rheumatoid arthritis, peripheral neuropathy and cardiac failure, need to be considered before applying compression.
Reasons for not assessing ABPI
There may be a number of reasons why patients do not undergo ABPI assessment when compression is indicated. Staines (2018) recognised that this may be due to a lack of clinician competency, time constraints and lack of suitable equipment. Further, if nurses are not carrying out the procedure regularly, it may take longer and be less accurate (Table 3). Additionally, contraindications to ABPI assessment include acute deep vein thrombosis, acute cellulitis and severe ischaemia.
Peripheral arterial disease
Peripheral arterial disease is characterised by the reduced supply of blood to the peripheries, that is, fingers and toes. It is often caused by atherosclerosis, thrombosis or embolism (Gogalniceanu et al, 2018). Peripheral arterial disease can also be associated with trauma, compression and/or changes in the arterial wall, for example, due to inflammation and thrombosis.
Vascular assessment
It is recognised that undertaking a vascular assessment involves much more than just establishing an ABPI (Scottish Intercollegiate Guidelines Network, 2010). It is important to remember that ABPI alone is not an indicator that a patient is suitable for compression therapy; all patients needing compression therapy greater than 17 mmHg require a full holistic assessment (Wounds UK, 2015).
The clinical knowledge summary provided by NICE (2018) for compression stockings states that assessment should include taking a detailed medical and surgical history (previous limb trauma and infection, comorbidities, medication, family history and risk factors of venous disease (previous limb surgery, deep vein thrombosis). Examination should then be performed, observing for signs of venous disease (varicose veins, venous dermatitis, haemosiderin staining, lipodermatosclerosis and atrophie blanche) and oedema and excluding non-venous causes. Arterial insufficiency should be excluded, and only then should the ABPI be measured.
Physical examination
There are several assessment methods other than ABPI that nurses can use to determine whether patients have peripheral arterial disease. These include assessment of capillary refill and palpation of pedal pulses in the foot.
Capillary refill
Capillary refill involves pressing on the toe or nail bed for 3 seconds so that it blanches, and then releasing the pressure and counting the time taken for colour to return. Sansone et al (2017) suggest a capillary refill time of 2 and 3 seconds for men and women under 65 years of age and one of 4 seconds for those of either gender older than 65 years.
Pedal pulses
Absent or diminished pedal pulses can indicate the presence of peripheral arterial disease. Nurses are rarely taught how to palpate pedal pulses, and, thus, one study of a cohort of community nurses found that palpation of pedal pulses alone is a suboptimal predictor of arterial disease (Morison and Moffatt, 1994). The same study also found that patients with neuropathy can have a strong pulse but reduced circulation; therefore, the test is not definitive.
A hand-held Doppler can be used to determine the presence and quality of pedal pulses. The waveform output and pulsatile sounds are important for differentiating triphasic, biphasic and monophasic pulses. These can help to establish the vascular status of the patient and when onward referral is necessary. Sánchez et al (2016), however, described how the inflammatory processes of soft tissues, such as erysipelas and cellulitis, lead to the release of histamine, prostaglandins and leukotrienes, which have a direct effect on the arteriolar walls and cause vasodilation. This in turn leads to greater blood flow to the affected area, which attracts a greater number of inflammatory mediators and stimulates the cycle. The consequent decrease in peripheral vascular resistance (due to vasodilation) alters Ltd the spectrum of the normal triphasic flow, turning it into lymphoedema, the fact that this may actually affect the monophasic flow. Although research is needed on the understanding of the inflammatory manifestations of Doppler waveforms is very interesting and needs to be taken into consideration.
| Patient-related factors |
| Diabetes |
| Arteriosclerosis |
| Renal disease |
| Cardiac arrhythmias, e.g. atrial fibrillation |
| Rheumatoid arthritis, scleroderma and related disease |
| Extrinsic factors |
| Inadequate preparation, e.g. room temperature |
| Inexperience of the operator |
| Patient anxiety |
| Repeated inflation by moving Doppler probe during the procedure |
| Incorrect positioning of the patient |
| Prolonged inflation of the cuff or re-inflation mid-procedure |
| Inappropriate gel |
| Releasing sphygmomanometer cuff too rapidly |
| Incorrect size of sphygmomanometer cuff |
| Excessive pressure on a vessel during the procedure |
| Wrong-sized Doppler probe |
| Miscalculation of reading |
| Incorrect positioning of Doppler probe over vessel |
Fear
An article by Vowden and Vowden (2001) highlighted the strong language used to describe the effects of applying inappropriate high-compression bandaging. It was emphasised as being dangerous and having the potential to place a limb at risk of damage and possibly even amputation.
Field (2004) conducted an audit in one trust, which highlighted a degree of diagnostic caution among district nurses whereby they erred on the side of caution, fearful of applying incorrect compression. This led to some patients not receiving the compression therapy that national guidelines recommend. Ruckley (2001) found that, when practitioners felt unsupported, reduced compression was often used despite the presence of guidelines. This highlights the need for documents like the BLS position paper on ABPI to support best practice and to recognise evidence that increasingly suggests that compression in arterial and mixed ulcers results in increased arterial perfusion (Mosti et al, 2012).
It is understood that reduced, light or modified compression (less than 40 mmHg at the ankle) has become the norm for a number of practitioners (Hopkins, 2018). This may be due to the fear of causing harm to the patient, either from inducing ischaemia or bandage trauma. Yet, the converse may be true: reduced compression also reduces effectiveness and exposes patients to harm from delayed or poor healing. Inability to obtain ABPI measurements due to the size of the limb, not having the correct equipment or lack of practitioner skills or time is often quoted where correct compression is not applied, which leads to increased time without healing, wound deterioration and, more importantly, poor patient experience. Hopkins (2018) asserted that reduced or light compression sounds friendly or kind, but, if the terms were changed to ‘weak’, ‘ineffectual’ or ‘sub-optimal’, there would be a better understanding of how care is being omitted in these cases and harm is being caused to patients’ lives. The use of compression therapy is about both competence and confidence (Hopkins and Worboys, 2005). There is also a very real case to answer in terms of resources being misspent. Guest et al (2018) demonstrated that the cost of managing an unhealed venous leg ulcer (VLU) was 4.5 times more than that of managing a healed venous leg ulcer (£3000 per healed VLU vs £13 500 per unhealed VLU).
Labelling patients ‘non-compliant’ or ‘non-concordant’
Many patients are labelled as ‘non-compliant’ or ‘non-concordant’ with compression. Although Hopkins and Worboys (2005) did not explore the complexities of non-compliance, they reported that few patients are truly unable to tolerate compression, and that the problem was massively outweighed by a general lack of understanding of the key principles of compression bandaging. Consequently, if practitioners understand compression therapy, its role and how it can be achieved successfully through a variety of techniques, the practitioner's skill will be increased and, consequently, so will the patient's tolerance for the therapy. Moore (2002) also recognised that application varied widely among practitioners, and a patient would often state which nurse they would prefer to apply their bandages. Edwards (2003) described the reduction in pain and discomfort when compression was appropriately applied. Thus, the practitioner's technique and the bandage system must be challenged when a bandage is not tolerated.
Vowden and Vowden (2012) described how a patient's initial experience with compression therapy may affect their acceptance in the long term, and that, in order to improve tolerance of the correct levels of compression, patients should be (1) engaged in treatment planning; social factors, for example, isolation; and (4) effectively (2) provided with sufficient information to understand the rationale for treatment; (3) holistically assessed to include treated for symptom control (either with dressings or analgesia).
As understanding of the anatomy and physiology of the vascular and lymphatic systems increases, there is a case for adapting traditional protocols to meet the needs of patients. Inelastic bandaging has been indicated in the management of lymphoedema, but it is difficult to apply this system with high pressure (Hopkins and Worboys, 2005). Additionally, due to increased limb volume in lymphoedema, the amount of compression applied may need to be increased according to the Law of LaPlace, in order to achieve wound healing or to reduce lymphorrhoea.
Conclusion
The BLS position paper on ABPI shows a need to focus on clinical assessment, rather than relying on an ABPI alone, and to recognise that it may be more harmful for the patient to omit, delay or reduce compression than to apply it. Failing to apply appropriate compression solely due to the absence of ABPI is unacceptable. Practitioners are dissuaded from taking risks in the application of compression and are rather encouraged to have the spirit and confidence to feel supported in their decision-making to apply compression after full vascular assessment in the absence of ABPI. The knowledge of when and how to refer a patient onwards is also paramount to ensure patient safety.