Understanding how compression works: part 1

Transcription

1 Understanding how compression works: part 1 Georgina Ritchie, Gillian Warwick Chronic leg ulceration is an increasing burden in the UK, both financially to the health service and on a human level. This first article in a four-part series, which looks at leg ulcer management and understanding compression therapy, explores the cardiovascular system, the underlying causes of lower limb problems, and the risk factors for leg ulceration. An overview of how compression therapy works and an introduction to the options available for patients and clinicians in this field of practice is also given. Subsequent articles in the series will look at holistic assessment and clinical decision-making in leg ulcer management, understanding compression hosiery and adjustable wraps, as well as compression bandaging and skin care. KEYWORDS: Leg ulceration Lower limb Compression therapy Cardiovascular system Leg ulcers, defined as loss of skin below the knee on the leg or foot, which takes more than two weeks to heal, are the most commonly encountered chronic wound within UK healthcare practice. With an estimated 730,000 people currently living with a leg ulcer, this equates to approximately 1.5% of the adult population (Guest et al, 2015). In financial terms, the burden to the NHS is around 400 million per year; a cost which has significant consequences for an already overstretched NHS budget (Ritchie, 2017). Therefore, promoting an optimum healing environment for those who have a leg ulcer, in addition to prevention of initial occurrence or re-occurrence, is a significant issue for clinicians (Wounds UK, 2016). Georgina Ritchie, senior lecturer, University of Central Lancashire, district nurse, Queen s nurse, member of the Association of District Nurse Educators; Gillian Warwick, senior lecturer, University of Central Lancashire In terms of human cost, leg ulcers can have a profound impact on quality of life (Adderley, 2015) and exacerbate social isolation, loneliness and depression all of which are frequently experienced by older people; those who are most at risk of leg ulceration. This economic and human burden is increasing as the UK population ages, coupled with an increase in long-term conditions and the ongoing issue of unhealthy lifestyles contributing to overall poorer health. As leg ulcers are a symptom of underlying disease, healing the ulcer does not remove its cause. Thus, once healed, patients who have had a leg ulcer should be reviewed on a 6 12 monthly basis for life (National Institute for Health and Care Excellence [NICE], 2016). Once patients have experienced the presence of skin loss on the lower limb below the knee on the leg or foot for two weeks, best practice recommends holistic assessment, including ankle brachial pressure index (ABPI) measurement, to determine the cause of the ulceration and to prepare a treatment plan appropriate for that patient (NICE, 2016). While many nurses working in the field report confidence in their clinical decisionmaking in terms of leg ulcer management, evidence exists to say that nurses could improve upon their clinical assessment within this complex field of practice (Adderley and Thompson, 2015). Although the benefits of compression therapy are widely recognised, it is frequently under- or inconsistently used (Harding et al, 2016). Further challenges exist in terms of national and local guidelines and policy within this field of practice, many of which are due for review. In light of new evidence and a drive by leaders in the leg ulcer field to be more proactive (Wounds UK, 2016; see pages 12 and 14 of this issue), this four-part series aims to visit the topic of leg ulcer management and compression therapy. NORMAL ANATOMY AND PHYSIOLOGY OF THE HEART Clinicians should be knowledgeable about the anatomy of a normal healthy cardiovascular system and have an understanding of the pathophysiological occurrences of disease and the subsequent clinical manifestations. Practice point In a healthy leg, the valves and calf muscle pump work together to push the blood back up the leg, but in patients who have damaged or aged valves, or limited calf muscle pump action due to immobility, a risk of pressure building up is common. 24 JCN 2018, Vol 32, No 2

2 le op Pe ar e 18 ing ABPI read inute! within 1 m 20 Helps you with your assessment and allows you to compress with confidence. 2 3 cm 13:12 Welcome to begin Step 1 Place cuffs on arm and legs medi. I feel better. 09:15 Results Please START/STOP ENTER START/STOP ENTER LEFT RIGHT ABI Brachial pressure SYS: DIA: Step 2 Press START button to run measurement ABI 125 mmhg 75 mmhg Heart rate 80 bpm Step 3 See the results Discover the medi Wound Care Therapy Chain within the medi World of Compression Manufactured by MESI, development of medical devices, ltd. Distributed by medi UK Ltd C nd ou W MESI ABPI MD

3 The cardiovascular system consists of the heart and blood vessels and is responsible for blood circulation to deliver oxygen and nutrients to the body. It is also involved in the removal of waste products of cellular metabolism. A normal, healthy heart beats approximately times per minute, although this can vary according to the body s requirements to maintain homeostasis. The heart is a hollow organ divided into four chambers, right and left atrium and the right and left ventricle. The upper chambers (atria) are mainly blood receiving chambers, and the lower chambers (ventricles) pump blood away from the heart to the lungs and the rest of the body (Figure 1). The chambers are separated by partitions called septum. Four one-way valves direct bloodflow through the heart and are located at the entrance and exit of each ventricle. The heart wall consists of three different layers, the pericardium, the myocardium and the endocardium. The pericardium forms a fibrous covering around the heart, holding it in place and acts as a protective layer. The myocardium is the muscular section containing muscle cells that contracts involuntarily and is the thickest layer of the heart. The endocardium is a thin, three-layer membrane that lines the heart and covers the valves. The heart s pumping action is regulated by an electrical conduction system that coordinates the contraction of the various chambers of the heart. The heart is unique compared with other muscles in that it can generate its own electrical impulses (Mattson Porth, 2015). Practice point Patients at risk of developing venous leg ulcers are: patients with a history of deep vein thrombosis (DVT), patients who are obese, have limited mobility or smoke, older people and those with a history of trauma to the lower limbs, such as breaks or joint replacements. NORMAL ANATOMY AND PHYSIOLOGY OF BLOOD VESSELS Blood vessels transport blood throughout the body. There are three major types: Arteries, which carry the blood away from the heart Veins, which carry blood back toward the heart Capillaries, where exchange of water and chemicals between the blood and tissues occurs. All blood vessels, except capillaries, have walls composed of three layers called tunicae: Tunica intima: innermost layer, consists of a single layer of flattened endothelial cells Tunica media: middle layer, consists of smooth muscle that enables vessels to constrict to control and regulate the diameter of the vessel Tunica externa: outermost layer, consists mainly of loosely woven collagen fibres that protect and anchor it to the surrounding structures. The arterial system comprises large and medium-sized arteries and arterioles. Arteries consist of large amounts of elastic fibres and are thick-walled. The elastin allows for the arteries to stretch during cardiac To body (systemic circulation) Oxygenated blood (red) becomes deoxygenated (blue) Practice point The principle aim of compression therapy is to aid venous return by encouraging venous blood to flow back up the leg towards the heart by applying external pressure to the leg. systole and recoil during diastole. The arterioles are mainly smooth muscle, which serve as resistance vessels for the circulatory system and act as control valves through which blood is released as it moves into capillaries. They are capable of constriction or relaxation, as needed, to maintain blood pressure. The arterial system is responsible for ensuring an oxygenated blood supply reaches the lower limbs to maintain homeostasis of the lower legs and feet. The venous system is a lowpressure system that returns blood back to the heart and consists of venules and veins. These are thinwalled, distensible and collapsible vessels and are capable of enlarging and storing large quantities of blood. As the venous system operates under such low pressures, blood flow must oppose the effects of gravity. This is maintained by the use of valves within the veins which act as oneway doors to prevent backflow and Figure 1. Two halves of the heart and their corresponding cardiovascular circuits. To lungs (pulmonary circulation) Unoxygenated blood (blue) becomes oxygenated (red) 26 JCN 2018, Vol 32, No 2

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5 Remember... Prolonged build up of pressure in the veins can cause damage to tissue and ultimately lead to a venous leg ulcer. Figure 2. Valves in the veins of the leg open to allow blood to return to the heart, and close to prevent venous backflow. the actions of the skeletal muscles in the foot and calf, which contribute to the pumping of bloodflow back to the heart (Figure 2). In terms of lower limb management, both the foot and calf muscle pumps play a major role in returning blood back up the lower limb towards the heart for reoxygenation. The microcirculation system consists of arterioles, capillaries and venules and are microscopic vessels (Figure 3). These thin walled vessels allow for water, lipid-soluble and water-soluble materials and waste materials to diffuse in and out of the circulatory system, ensuring that homeostasis is maintained by delivering and removing water, nutrients and waste as needed (Mattson Porth, 2015). DISORDERS OF THE CIRCULATORY SYSTEM Many diseases can be directly or indirectly associated with disorders of the blood vessels. Disorders of the heart include acute coronary syndrome, ischaemic heart disease and valvular disease. Disorders of the blood vessels include peripheral arterial disease (PAD), vasculitis, venous hypertension, varicose veins and venous thrombosis, although neither list is exhaustive. For lower limb management, it is prudent to subdivide disorders of the circulatory system into arterial and venous, as the underlying pathophysiological problem will inform how signs and symptoms are managed by the clinician and patient in partnership. Arterial disorders The most significant issue in terms of lower limbs is PAD. This is when arteries become narrowed by a gradual build-up of fatty material (atheroma) within their walls. The development of atherosclerotic lesions is a progressive process involving endothelial cell injury, migration of inflammatory cells, smooth muscle cell proliferation and lipid deposition, and gradual development of atheromatous plaque formations (Mattson Porth, 2015). As the arteries become increasingly blocked, blood supply to the lower limbs and feet becomes increasingly hindered. This results in decreased oxygenation to the legs and feet, which can result in the development of arterial ulcers, poor wound healing, skin changes and thickening of the toe nails, and even loss of toes or limbs. Risk factors associated with atherosclerosis include nonmodifiable factors, such as; Increasing age Male gender Genetic disorders of lipid metabolism Family history. Potentially modifiable factors include: Cigarette smoking Obesity Hypertension Hyperlipidaemia Diabetes mellitus (McCance and Huether, 2014). Health promotion is a fundamental aspect of all clinical practice and therefore any opportunities to promote health and influence lifestyle choices should be seized (Public Health England [PHE], 2014). This is particularly pertinent to clinicians who are planning care with patients who have PAD. Venous disorders The most significant is chronic venous insufficiency (CVI), which results in venous hypertension and can lead to several clinical manifestations, including, to name but a few: Ankle flare Hyperpigmentation Varicose eczema Development of venous leg ulcers. Chronic venous insufficiency occurs when the valves attached to the vein walls in both the superficial and perforator veins of Arteriole Artery Capillaries Venule Tissue cells Figure 3. Blood vessels involved in the microcirculation. Vein 28 JCN 2018, Vol 32, No 2

6 the leg do not function effectively. As previously discussed, within the vein walls are valves that act as oneway doors to prevent backflow of blood. When the valves fail, reflux or backflow occurs and all the blood is not pushed back towards the heart. This results in a build up of blood in the veins causing high pressures, also known as venous hypertension. Over time, this hypertension causes damage to the veins, and prolonged venous hypertension leads to permeable capillaries and consequently proteins and fluids leak from the valves into the surrounding tissues, which causes hardening, changes in appearance, and vulnerability to tissue breaking down (Wounds International, 2013). Red Flags Patients who have peripheral arterial disease or arterial lower limb ulcers should be referred to a specialist for assessment and should not be prescribed compression therapy without specialist advice. Patients who have diabetes should not routinely be prescribed compression therapy without assessment and advice from a healthcare professional who has confidence and competence in diabetic foot ulcer management. In both of these patient groups, a balance should be achieved, i.e. sufficient compression to aid venous return and therefore relieve venous hypertension, but without compressing the arteries (Butterfield, 2013). This is because oxygenation to the limb is often affected by peripheral arterial disease in both of these patient groups and compressing already semi-occluded arteries will further hinder oxygenation to the limb. Further reduction in oxygenation can cause damage to the limb or even amputation (Vowden and Vowden, 2001). In these patients, reduced compression under specialist direction is necessary to achieve a balance between compression of the veins, while allowing flow in the arteries. Mixed venous/arterial disorders Some patients presenting with a leg ulcer will have a combination Compression therapy works by applying external pressure to the lower limb, which assists both the lymphatic system to reduce oedema and the venous system to encourage venous blood to return from the lower limb back towards the heart. of underlying venous and arterial disease these ulcers are normally classified as being of mixed aetiology. As the term implies, these patients have venous disease and a significant level of arterial involvement, although the arterial disease is not extensive enough to cause critical ischaemia (Butterfield, 2013). Arterial disease is usually progressive in nature, subsequently it will worsen over time and so regular reassessment is particularly important for this group. It is likely that in time the arterial aetiology will become more significant than the venous aetiology, which in turn will affect treatment options available to the patient. HOW COMPRESSION THERAPY WORKS Compression therapy is a suitable option for patients who have arterial, venous and mixed risk of ulceration, or actual ulceration, subject to holistic assessment and ABPI examination by an appropriately trained professional. However, caution should be exercised, particularly in applying compression to patients who have arterial disease or a diagnosis of diabetes (see Red flags box). Therefore, only clinicians who are competent and confident and suitably experienced and educated to manage the risk involved in applying compression to these groups should undertake this type of treatment. Practice point Prevention is always better than cure. Clinicians who recognise those at risk should give health promotion advice and instigate prevention measures to stop skin breakdown from occurring. The scope of this article is to explain how compression therapy works in patients who have had the presence of significant arterial disease ruled out and suitability for compression within the framework of venous leg ulcer care established. This is normally done through holistic assessment by a trained individual and should involve ABPI assessment (Mahoney, 2017), which will be visited later in this fourpart series. Pressure in the venous system overall and lower limb in particular alters during lying down, standing, rising and movement. When a person moves from a lying or sitting position to stand up, pressure in the venous system increases. If the person then begins to move or walk around, pressure reduces, and when the person ceases movement, pressure raises again. This rise and fall is due to the effects of gravity pulling the blood downwards, balanced against the counter attempts of the limb and body which are trying to overcome gravity by pushing the blood back upwards. This leads to the normal rise and fall of venous pressure within the body on movement and rest (Wounds International, 2013). Compression therapy works by applying external pressure to the lower limb, which assists both the lymphatic system to reduce oedema and the venous system to encourage venous blood to return from the lower limb back towards the heart; removing waste products of cellular metabolism from the limb and achieving re-oxygenation of the blood (Brown, 2017). In patients who have venous leg ulcers, often several pathophysiological problems occur, JCN 2018, Vol 32, No 2 29

7 such as valvular damage to the veins and immobility issues, which affect the ability of the foot and calf muscle pumps to overcome gravity and return blood back up the leg. Compression therapy provides external support to the lower limb to help overcome these problems, subsequently reducing the pressure build up which can cause venous hypertension (European Wound Management Association [EWMA], 2016). In short, the external pressure applied to the limb during compression therapy works by supporting the damaged valves to function within the vein and to overcome other exacerbatory factors, such as immobility (Wounds International, 2013). COMPRESSION THERAPY OPTIONS Leg ulcer care planning, prescribing, and applying compression therapy are influenced by several factors in practice. These can be broadly grouped into: The clinician managing the care The patient as an active participant in care Having read this article, Your knowledge of the cardiovascular system Revalidation Alert When patients should be referred for specialist assessment before prescribing compression therapy The importance of involving patients in their own care and explaining the different compression treatment options available. Then, upload the article to the free JCN revalidation e-portfolio as evidence of your continued learning: External influences (Lawrenson, 2014). In terms of the clinician, confidence and competence to advocate the right level of compression is an important factor. Within clinical practice, suboptimal care is sometimes offered as clinicians provide so-called reduced compression (Harding, 2016). Often, this is due to the belief that To make competent decisions in holistic care of patients with leg ulcers or lower limb conditions, clinicians need underpinning knowledge of the anatomy of a normal cardiovascular system and the pathophysiology that can occur. some compression is better than none (Butterfield, 2017). While this is indeed true (Wounds UK, 2016), clinicians deciding to offer reduced compression based purely on assumptions about what the patient can tolerate and manage without first trialing the optimal level of compression put the patient at risk of harm. Shared decision-making between healthcare professionals and patients is of paramount importance in leg ulcer care (Newton, 2015), and is often influenced by the patient s previous experiences with compression therapy. Failure to include the patient in the decision-making process may mean that they simply will not follow the treatment option recommended (Wicks, 2016). Finally, in the authors clinical experience, external influences, such as pharmaceutical companies, prescribing formularies within NHS trusts, and relationships with the wider leg ulcer management team can affect the treatment options available. It is advocated that local trust policy and guidance is consulted when making the decision about which therapy to choose in leg ulcer management (Lawrenson, 2014). Consequently, choosing the right option for compression therapy can be confusing for clinicians, who will find a plethora of choices exist when selecting compression systems that can be used to manage venous leg ulceration. Furthermore, in the authors clinical experience, conflicting evidence within the literature, frequently outdated clinical guidance and custom and practice among practitioners can influence the clinician s decision on which options are suitable and effective in managing venous leg ulceration. In addition, beyond the standard therapies seen in most clinical arenas, emerging evidence on the value of advanced techniques, such as multiple hosiery layering, use of strapping, and employment of extra high compression exist (Hopkins et al, 2011; 2017). Once the cornerstone of good practice has been undertaken, i.e. comprehensive holistic assessment (Atkin and Tickle 2016), for those with an active venous leg ulcer, broadly speaking, three options are available: Compression bandages (this includes inelastic two-layer and elastic four-layer bandage systems) Compression hosiery kits (also known as leg ulcer hosiery kits or two-layer hosiery) Adjustable compression wraps. Although compression hosiery kits are presented as first-line treatment in specific patients assessed as suitable for this therapy option (Wounds UK, 2016), the three options can be viewed as a continuum, being used as appropriate for the patient as indicated by ongoing holistic assessment. Each will be explored in detail later in this four-part series on compression therapy. CONCLUSION To make competent decisions in holistic care of patients with leg ulcers or lower limb conditions, 30 JCN 2018, Vol 32, No 2

8 le op Pe Outstanding Practice in Wound Care Award 2018 C ar e Nominate yourself, colleagues or team to celebrate achievements in wound prevention and management in the community W ou nd Do you know anyone who is making a real difference to patients wound care in your area? Maybe you are proud of something you have achieved and feel others could benefit from sharing this experience? To enter, simply visit How to enter You will be asked to submit a written statement of words, considering the questions below, to support why you feel this nurse/team has made an outstanding contribution to wound care practice. What exceptional impact has their practice/care had on their colleagues and/or patients? What specific initiative have they instigated that has made a real difference to patient lives? Is there any one patient episode that stands out as exceptional practice in challenging circumstances? How has this contribution affected patient care? How has this contributed to tissue viability nursing overall? Is there any evidence to support the entry (national guidelines, literature, etc). This award is in partnership with

9 clinicians need underpinning knowledge of the anatomy of a normal cardiovascular system and the pathophysiology that can occur. Being able to make sound judgements about the underlying causes of problems and the clinical manifestations observed in the clinical arena is vital. An understanding of how compression therapy works and the ability to select the right type of treatment for and with the patient, balanced against frequently conflicting guidance, custom and practice, and the emergence of new literature in the field, is an important skill for clinicians to offer both competent and confident lower limb care. JCN REFERENCES Adderley U (2015) Prescribing for the management of venous leg ulcers. Nurse Prescriber. Available online: www. magonlinelibrary.com/doi/abs/ / npre (accessed 21 February, 2018) Adderley U, Thompson C (2015) Community nurses judgement for the management of venous leg ulceration: A judgement analysis. Int J Nurs Studies. Available online: www. journalofnursingstudies.com/article/ S (14) /abstract (accessed 21 February, 2018) Atkin L, Tickle J (2016) A new pathway for lower limb ulceration. Wounds UK 12(2): 32 6 Brown A (2017) Dealing with common lower limb problems in primary care: part two. J Community Nurs 31(4): Butterfield H (2013) The use of compression hosiery in mixed aetiology ulceration and palliative care. J Community Nurs 27(5): 60 5 Butterfield H (2017) Role of self-care to prevent venous leg ulcer recurrence. J General Practice Nurs 3(3): European Wound Management Association (2016) Management of patients with venous leg ulcers. Challenges and current best practice. J Wound Care 25(6): S1 S167 Guest JF, Ayoub N, McIlwraith T, Uchegbu I, Gerrish A, Weidlich D, Vowden K, Vowden P (2015) Health economic burden that wounds place upon the National Health Service in the UK. Br Med J Open 5. Available online: com/content/5/12/e (accessed 5 February, 2018) Harding K (2016) Challenging passivity in venous leg ulcer care the ABC model of management. Int wound J 13(6): Hopkins A, Worboys F, Bull R, Farrelly I (2011) Compression strapping: the development of a novel technique to enhance compression therapy and healing for hard to heal leg ulcers. Int Wound J. Available online: nih.gov/pubmed/ (accessed 5 February, 2018) Hopkins A, Bull R, Worboys F (2017) Needing more: the case for extra high compression for tall men in UK leg ulcer management. Veins and Lymphatics. Available online: org/index.php/vl/article/view/6630 (accessed 5 February, 2018) Lawrenson V in Nuttall D, Rutt-Howard J (2014) The textbook of non-medical prescribing. 2nd edn. Wiley Blackwell, Chichester Mahoney K (2017) Unravelling compression therapy for venous leg ulcers in general practice. J General Practice Nurs 3(3): Mattson Porth C (2015) Essentials of Pathophysiology. 4th edn. Wolters Kluwer, Philadelphia McCance KL, Huether SE (2014) Pathophysiology: The biology basics for disease in adults and children. 7th edn. Elsevier Mosby, St. Louis, Missouri National Institute for Health and Care Excellence (2016) Clinical knowledge Summaries. Leg ulcer venous. NICE, London. Available online: org.uk/leg-ulcer-venous#!topicsummary (accessed 3 February, 2018) Newton H (2015) Impact of compression therapy on chronic venous disease. Wound Essentials 10(2): Available online: Public Health England (2014) From evidence into action: opportunities to protect and improve the nation s health. Available online: system/uploads/attachment_data/ file/366852/phe_priorities.pdf (accessed 5 February, 2018) Ritchie G (2017) Chronic leg ulcers. Nurse Prescriber. Available online: www. magonlinelibrary.com/doi/abs/ / KEY POINTS Leg ulcers are the most commonly encountered chronic wound within UK healthcare practice. As leg ulcers are a symptom of underlying disease, healing the ulcer does not remove its cause. Clinicians should be knowledgeable about the anatomy of a normal, healthy cardiovascular system and have an understanding of the pathophysiological occurrences of disease and the subsequent clinical manifestations. Best practice recommends holistic assessment, including ankle brachial pressure index (ABPI) measurement, to determine the cause of ulceration and prepare an appropriate treatment plan. Shared decision-making between healthcare professionals and patients is of paramount importance in leg ulcer management. npre (accessed 21 February, 2018) Vowden P, Vowden K (2001) Doppler assessment and ABPI: interpretation in the management of leg ulceration. World Wide Wounds. Available online: www. worldwidewounds.com/2001/march/ Vowden/Doppler-assessment-and-ABPI. html Wicks G (2016) Innovative compression therapy systems can improve practice. J General Practice Nurs 2(3): 26 7 Wounds International (2013) Principles of compression in venous disease: A practitioners guide to treatment and prevention of venous leg ulcers. Available online: media/issues/672/files/content_10802.pdf (accessed 5 February, 2018) Wounds UK (2016) Best Practice Statement: Holistic management of venous leg ulceration. Wounds UK, London. Available online: 32 JCN 2015, 2018, Vol 29, 32, No 52

10 For the 730,000 leg ulcer patients in the U.K. Every Moment Matters Atkin and Critchley (2017) reported service improvements through implementing the Best Practice Statement leg ulcer treatment pathway. 43% Optimisation of resources, including utilisation of healthcare assistant s skills Signifi cantly improved outcomes, including improved healing A 43% reduction in appointments for leg ulcer To fi nd out how L&R can support your organisation to achieve these results customercare@uk.lrmed.com quoting every moment matters ADV292 V1.1