In England over people die from hospital-acquired. Venous thromboembolism: use of graduated compression stockings. Abstract

Transcription

1 Venous thromboembolism: use of graduated compression stockings Gloria Patricia Muñoz-Figueroa and Omorogieva Ojo Abstract This article aims to review the use of graduated compression stockings in the prevention of venous thromboembolism (VTE). This is particularly important owing to the increasing number of people who die from hospital-acquired VTE and deep vein thrombosis. In addition, there is the need to raise awareness among nurses and other health professionals on the overall impact of VTE, and the number of patients with a range of conditions including cancer who may be at risk of developing VTE. Graduated compression stockings, when used alone, have been found to be effective in preventing VTE in a number of patients in hospital and community settings. However, there is evidence that when used together with other preventative measures such as pharmacological prophylaxis are more effective than graduated compression stockings alone. It is also important that the correct size of graduated compression stocking is used and how they are applied as these may have a significant impact on VTE. The role of the nurse in thromboprophylaxis and implications for practice are discussed. Key words: Venous thromboembolism Compression stockings Pulmonary embolism Risk factors In England over people die from hospital-acquired venous thromboembolism (VTE) and deaths are attributed to deep vein thrombosis (DVT) every year. More alarming is the fact that VTE and the deaths caused by it are still number one preventable cause of hospital death (Department of Health and Chief Medical Officer, 2007; Agency for Healthcare Research and Quality (AHRQ), 2010; National Institute for Health and Care Excellence (NICE), 2010). However, evidence shows that there is a lack of awareness among nurses and other health professionals about the extent of VTE incidence (House of Commons Health Committee, 2005). By assessing patients to identify those who are at a greater risk of developing VTE and implementing both mechanical and pharmacological thromboprophylaxis measures, many unnecessary deaths could be prevented (Royal College of Nursing (RCN), 2015). The most common risk factors for developing blood clots are: family history, inactivity Gloria Patricia Muñoz-Figueroa, Staff Nurse, Main Haemodialysis Unit, Renal Department, King s College Hospital NHS Foundation Trust; Omorogieva Ojo Senior Lecturer in Primary Care, Faculty of Education and Health, University of Greenwich, London Accepted for publication: June 2015 or stasis, hypercoagulability (dehydration, infection, cancer), surgery, inflammation or the use of the contraceptive pill (Anderson and Spencer, 2003; House of Commons Health Committee, 2005). During a hospital stay, there is a high risk of developing VTE (Clots in Legs Or stockings after Stroke (CLOTS, 2010). Therefore, it is essential that all patients undergo a mandatory VTE risk assessment to determine the individual risk of forming thrombus in order to select the appropriate method of thrombophrophylaxis for the individual. Without the use of thromboprophylaxis methods, the incidence of VTE would be higher (Nicolaides et al, 2006). This means that patient compliance is also important. This article will review the use of graduated compression stockings as a valid and effective mechanical prophylaxis measure to prevent VTE. This is important to promote better usage, especially for those who can only rely on mechanical thromboprophylaxis methods because of the high risk of bleeding. The clinical implications for nurses in hospital and community settings in terms of understanding the signs and symptoms of VTE and actions to take in its management are also discussed. The use of graduated compression stockings Graduated compression stockings when used alone are an effective prophylaxis measure to prevent VTE in a variety of high-risk patients (May et al, 2006; The Joanna Briggs Institute, 2008). Graduated compression stockings increase the velocity of venous outflow, prevent venous stasis and distension, and promote emptying of valvular cusps, therefore they reduce the risk of DVT (Agu et al, 1999; MacLellan and Fletcher, 2007). There are a number of companies that manufacture graduated compression stockings including Medi UK, Activa and Mimosa. Rimaud et al (2008) found that 21 mmhg knee-length graduated compression stockings are effective in preventing venous distension in people with spinal cord injury. Nine men with spinal cord injury were recruited for the study and all participants performed two plethysmography tests, with graduated compression stockings in situ and without. This study demonstrated a clear and simple objective of assessing the effectiveness of graduated compression stockings on venous capacitance and venous outflow in spinal cord injury patients. However, Rimaud et al (2008) used a very small sample size, which means the results cannot be used as a basis from which to draw wider conclusions (Bowling, 2005). As this study was specific to high-level and low-level spinal cord injury, the results cannot be generalised to other patient groups. Finally, it would appear that pressure of 21 mmhg 680 British Journal of Nursing, 2015, Vol 24, No 13

2 at the ankle and 15 mmhg at the calf is adequate to have a beneficial effect on venous capacitance but insufficient to affect venous outflow (Rimaud et al, 2008). In a study by Jamieson et al (2007) involving 17 women following day 1 or 2 of vaginal delivery, patients measurements were assessed by a single observer before and while graduated compression stockings were in situ to deliver a pressure of 18 mmhg at the ankle. A significant reduction in the diameter of the common femoral vein (CFV) after graduated compression stockings were applied was found. Similarly, Sajid et al (2008) reviewed nine trials evaluating the use of graduated compression stockings. A total of 46 out of 1261 participants in the control group developed DVT compared with 2 out of 1237 participants in the graduated compression stockings group. In contrast Blaivas (2009) found no reduction in the risk of proximal DVT, symptomatic proximal DVT, any DVT and pulmonary embolism (PE). However, an increase in skin complications was noted. Skin breaks, ulcers, blisters and necrosis developed in 5.1% of patients allocated to wear graduated compression stockings, compared with 1.3% of patients not wearing the stockings. A study by Winslow and Brosz (2008) also found that graduated compression stockings can be harmful to the skin. According to Winslow and Brosz (2008), graduated compression stockings were used incorrectly in 29% of patients and sized incorrectly in 26% of patients. This may account for the reason that Winslow and Brosz (2008) recommended that nurses and patients be educated in regards to VTE and its mechanical prophylaxis because of the complications that may arise when not used correctly. Graduated compression stockings used with pharmacological thromboprophylaxis Graduated compression stockings when used in conjunction with other methods of prophylaxis are 60% more effective than graduated compression stockings alone (Byrne, 2001). Moreover, in the UK, patients assessed to be at risk of developing VTE are offered VTE prophylaxis in accordance with NICE recommendations and local protocols. According to NICE, aside from encouraging patients to mobilise as soon as possible, they should be offered graduated compression stockings during hospital admission and pharmacological thromboprophylaxis should be added (NICE, 2010). Considering the risk of bleeding, anticoagulants should not be given unless the risk of developing VTE outweighs the risk of bleeding (NICE, 2010). In a randomised controlled trial conducted by Camporese et al (2008), low-molecular-weight heparin (LMWH) was compared with compression stockings for thromboprophylaxis after knee arthroscopy. Camporese et al (2008) found that the 3-month cumulative incidence of asymptomatic DVT, symptomatic DVT and all-cause mortality was 3.2% (21/660 patients) in the graduated compression stockings group, 0.9% (6/657 patients) in the 7-day LMWH group and 0.9% (4/444 patients) in the 14-day LMWH group. The cumulative incidence of clinically significant bleeding events was 0.3% (2/660 patients) in the stocking group, 0.9% (6/657 patients) in the 7-day LMWH group and 0.5% (2/444 patients) in the 14-day LMWH group. In this study, graduated compression stockings were worn on the operated leg only, and all DVTs were detected on these legs, therefore high levels of compression were applied to the operated leg but none to the leg that had not been operated on. In the UK, NICE guidance on VTE prophylaxis recommends lower levels of compression of mmhg (NICE, 2010) which in practice are mainly applied to both legs. Despite using larger sample groups and recognised methods of statistical analysis, various weaknesses and limitations were demonstrated in this study. For example, the research was carried out in an outpatient setting and the patients were taught how to do their own injection and how to apply the graduated compression stockings by a nurse. However, because they were not in a hospital setting, it is possible that some patients did not comply strictly with the requirements of the study. In addition, the differences in the recommended method of usage of graduated compression stockings make it difficult to conclude that they are not as effective as LMWH in patients undergoing knee arthroscopy. Cohen et al (2007), in a study on the use of graduated compression stockings in association with fondaparinux in surgery of the hip found that the prevalence of DVT was 5.5% (22/400 patients) in the fondaparinux group and 4.8% (19/395 patients) in the fondaparinux plus graduated compression stockings group. Fondaparinux sodium is a synthetic pentasaccharide and a selective activator factor X (factor Xa) inhibitor (Garwood et al, 2012; Delavenne et al, 2012). It is used for the prevention of VTE after major orthopaedic surgery and there is evidence that it is effective and safe at the once-daily subcutaneous dose of 2.5 mg (Delavenne et al, 2012). However, graduated compression stockings may be costly, time-consuming to measure and fit, and the use of parenteral anticoagulation may enhance patients overall quality of life (Cohen et al, 2007). In addition, Cohen et al (2007) recommended that graduated compression stockings usage be replaced with an extended period of anticoagulants. It is now clear that, despite national recommendations in favour of combined mechanical and pharmaceutical thromboprophylaxis (The Association of Coloproctology of Great Britain and Ireland, 2007; NICE, 2010), there is a small percentage of local protocols opting for pharmacological prophylaxis only. Srinivasaiah et al (2012) found that 100% of participants in response to a questionnaire (n=490) reported the routine use of thromboprophylaxis, combined prophylaxis was used by 247 (95%) and 12 (5%) used medical prophylaxis only, preferring LMWH. Length of graduated compression stockings Sizing and applying graduated compression stockings the right way is essential to preventing VTE in patients at risk (Winslow and Brosz, 2008). However, there is no standardised policy as to whether the GCS should be below or above the knee (Hayes et al, 2002), although there is strong evidence to support the use of knee-length instead of thigh-length graduated compression stockings. This is because the kneelength graduated compression stockings have the same effect as thigh-length graduated compression stockings (Hameed et al, 2002) and removes the tourniquet effect, which is characteristic of thigh-length graduated compression stockings (Byrne 2001; Walker and Lamont, 2007). According to Winslow and Brosz (2008), nurses tend to 682 British Journal of Nursing, 2015, Vol 24, No 13

3 PREVENTION size and apply the stockings incorrectly. These issues are more common with thigh-length graduated compression stockings (Barker and Hollingsworth, 2004), which can roll down, acting as a tourniquet and increasing the risk of developing DVT. In contrast, the CLOTS trial collaboration (2010) found that patients with stroke are more likely to develop proximal DVT when below-knee graduated compression stockings are applied as a mechanical thromboprophylaxis than thighlength stockings. In the study, 3114 immobile hospitalised patients with acute stroke were recruited. A total of 1552 patients were allocated to wear thigh-length graduated compression stockings and 1562 patients were allocated to below-knee graduated compression stockings. Symptomatic or asymptomatic DVT occurred in 98 patients (6.3%) from the thigh-length graduated compression stockings group and 138 (8.8%) from the below-knee graduated compression stockings group. A total of 75% of patients in both groups wore the stockings for 30 days until they were discharged, died or regained mobility. Skin breaks occurred in 61 patients (3.9%) from the thigh-length graduated compression stockings group and in 45 patients (2.9%) who received below-knee graduated compression stockings. The small advantage does not appear to be clinically significant, and it is useful to take into account the adverse effects. Skin complications such as skin breaks, ulcers, blisters and necrosis were more common in patients wearing thigh-length graduated compression stockings. Therefore, CLOTS (2010) concluded that high-length graduated compression stockings are not clinically effective in reducing the risk of proximal DVT after stroke, and that it increases skin complications. The role of the nurse in thromboprophylaxis and implications for practice Nurses play a pivotal role in patient education regarding VTE. If patients are well informed about VTE, its complications and fatal consequences, they could appreciate more the thromboprophylaxis measures available and in turn this may increase compliance. Pharmacological thromboprophylaxis is offered when patients have a low risk of bleeding to reduce the risk of forming thrombus. This might be a LMWH or another anticoagulant medicine (RCN, 2015). Mechanical methods of thromboprophylaxis refer to graduated compression stockings, intermittent pneumatic compression and/or foot pumps (Rawat et al, 2008; RCN, 2015). With respect to graduated compression stockings, its use has been more emphasised in surgical settings, especially in orthopaedic and cardiothoracic surgery. However, a higher number of hospitalised patients in medical wards develop VTE because they present with certain conditions that increase their risk, such as severe heart failure, chronic respiratory disease, sepsis and cancer (House of Commons Health Committee, 2005; Goldhaber, 2010). In practice, any one of the pharmacological VTE prophylaxis may be offered to patients for 5 7 days until discharge despite recommendations by the American College of Chest Physicians for a minimum of days and up to 5 6 weeks following hip surgery (Cohen et al, 2007). In patients at risk of developing VTE and in whom pharmacological VTE prophylaxis is contraindicated, it may be helpful to use graduated compression stockings in managing these patients (Agency for Healthcare Research and Quality, 2014). Many of these patients will be referred to the primary care services, where community nurses will continue their care. This may explain why community nurses and specialist nurses encounter a number of post-surgical patients using graduated compression stockings, as well as patients with chronic diseases being treated in the community who are at high risk of VTE. Roberts et al (2013) noted that the prevention of VTE was the top national priority in In acute settings nurses are involved in multidisciplinary teams which may include the VTE specialist nurses whose expertise interlink to assess and minimise patient risk of VTE. In the community, nurses have a responsibility to recognise the signs and symptoms of VTE and PE, as well as taking appropriate action in a timely manner. In addition, a combination of clinical signs, symptoms and risk factors may be used to categorise patients into low, moderate or high risk, based on the probability of patients developing PE or DVT (Wells and Anderson, 2013) (Box 1). In the community, nurses review a patient s medical history, together with presenting symptoms to identify the patient s risk of VTE. Other roles of the nurse in the management of VTE have been outlined in Box 1. When caring for a patient with graduated compression stockings, community nurses should Box 1. Factors taken into account when assessing risk of venous thromboembolism Predisposing characteristics Age History of venous thromboembolism (deep vein thrombosis/pulmonary embolism) Active cancer Immobilised or bedridden (following recent surgery or fracture) Signs Pain in limb Swelling Raised heart rate Haemoptysis (coughing up blood) Adapted from Wells and Anderson, 2013 Box 2. Potential role of the nurse in the management of venous thromboembolism Assessing a patient s risk of venous thromboembolism (VTE) Assessing a patient s risk of haemorrhage Preparing and delivering a dose of a low-molecular-weight heparin (LMWH) Counselling/educating patients on key issues of anticoagulation Starting patients on a vitamin K antagonist (VKA) Adjusting the dose of a patient s VKA Determining a patient s international normalised ratio (INR) from a near-patient testing device Determining a patient s renal function via urea and electrolytes tests, and dose adjusting if necessary Referring to A&E in the case of actual or potential haemorrhage Delivering oral vitamin K when there is a high INR Determining possible heparin-induced thrombocytopenia via a full blood count and, if present, consider an alternative anticoagulant Source: Blann, 2014 British Journal of Nursing, 2015, Vol 24, No

4 be able to assess the use of graduated compression stockings because inadequate usage or sizing could potentially increase the risk of VTE through the tourniquet effect. Another key role of the community nurses is educating and reinforcing patient knowledge and understanding of the importance of the correct use of graduated compression stockings and their benefits. Nurses should be alert to query a patient s mobility and refer back to the relevant multidisciplinary team (physiotherapists, specialist nurses and consultants) in the secondary care by communicating effectively any concerns. When community nurses suspect VTE is present, they should refer the patient to A&E as soon as possible. According to Sweetland et al (2009), the risk of VTE and PE after surgery is higher in the first 12 weeks after surgery. Symptoms of PE vary from sudden death to silent emboli (Kumar et al, 2010). Therefore, as nurses, the assessments, role, the time spent with the patients and the quality of patient information collected, indicate the need for nurses to develop an awareness to recognise the signs and symptoms of VTE promptly and to take appropriate action. A VTE risk assessment is well established in hospital settings, as well as a checklist for the correct usage of graduated compression stockings. Therefore, if patients are discharged from hospital with graduated compression stockings, there should be a standardised framework in the community with a checklist for the assessment and monitoring of the risk of VTE and the thromboprophylaxis already in use. In addition, there should be access to the previously assessed levels of risk for a direct comparison. This should help nurses to identify trends in cases where VTE occurs after hospital discharge. Graduated compression stockings are the most common method of mechanical thromboprophylaxis used, because of their relative cost, accessibility and patient preference (Gee, 2011). When used correctly, graduated compression stockings help to prevent venous distension and venous stasis by applying different pressure in various areas of the leg to promote venous return (Gee, 2011; Thrombosis UK, 2014). However, in practice, it has been observed that some inpatients are offered graduated compression stockings in a perfunctory manner. In most cases, there is poor or limited patient education with respect to VTE owing to the busy work environment. Very often, patients are provided with the wrong stocking size; too long, too short, too loose, too tight and some clearly cutting into the leg and preventing KEY POINTS Graduated compression stockings have been found to be effective in preventing venous thromboembolism (VTE) in a number of patients in hospital and community settings Graduated compression stockings, when used in conjunction with other methods of VTE prophylaxis, are more effective than stockings alone Sizing and applying graduated compression stockings the right way is essential to preventing VTE in patients at risk Nurses play a significant role, including providing education, when managing patients with VTE who require the use of graduated compression stockings good circulation rather than improving it (Byrne, 2001). This could be owing to the implementation of a wrong sizing technique. Explaining how to wear the stockings correctly is essential; pulling them up smoothly, making sure there are no wrinkles and that there is no pulling back over the toes which can cause skin sores from the elastic. In addition, stockings must be removed everyday for inspection of the skin for all patients, especially those with diabetes as they are at greater risk of developing neuropathy and foot problems (Agency for Healthcare Research and Quality, 2014). This aspect of practice is of great importance because of its extended relevance to various clinical settings and disciplines; surgical, medical, pregnant women and most adults. In order to improve practice, various hosiery companies across the UK provide education to nurses through training and study day programmes, often delivered by clinical nurse advisors. Conclusions and recommendations Graduated compression stockings can prevent venous distension and venous stasis which may help in preventing DVT. Graduated compression stockings can cause skin complications, but this can be monitored and action can be taken to address the risks. Graduated compression stockings have demonstrated a reduced incidence of haemorrhage, therefore would benefit patients for whom anticoagulants cannot be administered. In addition, graduated compression stockings are an appropriate, alternative mechanical thromboprophylaxis suitable for various groups of adult patients. Sizing and applying graduated compression stockings the right way is essential to preventing VTE. Knee-length graduated compression stockings are easier to size as fewer measurements need to be made, while thigh-length graduated compression stockings require more measurements to be taken in order to apply the correct size. If wrongly sized and applied, this may exacerbate the tourniquet effect which increases the risk of developing DVT. The limited advantage of applying thigh-length graduated compression stockings to patients with stroke does not appear to be significant as it is necessary to take into account the adverse effects such as skin breaks, ulcers, blisters and necrosis, especially in patients with compromised movement and mobility. Although kneelength graduated compression stockings have been proposed to be used as the standard length of graduated compression stockings to prevent VTE, there appears to be no clear policy to establish the correct length to be used, and this should be determined according to the individual and his or her specific medical or surgical need. Therefore, more training should be provided to nurses in order to improve their knowledge of VTE and how to size and apply graduated compression stockings to patients to reduce the risk of developing VTE. Patients should be educated more specifically on the benefits and correct use of graduated compression stockings to increase treatment compliance. Finally, more research should be conducted in the UK on the use of graduated compression stockings as prophylaxis in order to prevent VTE because of the limited number of studies in this area of practice. BJN Conflict of interest: none 684 British Journal of Nursing, 2015, Vol 24, No 13

5 PREVENTION Agency for Healthcare Research and Quality (2010) Venous Thromboembolism (VTE) Prevention in the Hospital. com/nzx454b (accessed 1 July 2015) Agency for Healthcare Research and Quality (2014) Venous thromboembolism: reducing the risk. Reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients admitted to hospital. (accessed 1 July 2015) Agu O, Hamilton G, Baker D (1999) Graduated compression stockings in the prevention of venous thromboembolism. Br J Surg 86(8): doi: /j x Anderson FA, Spencer FA (2003) Risk factors for venous thromboembolism. Circulation 107(23 Suppl 1): I9 16. doi: /01. CIR E6 The Association of Coloproctology of Great Britain and Ireland (2007) Guidelines for the Management of Colorectal Cancer (3rd edn). tinyurl.com/olsherr (accessed 26 June 2015) Barker SGE, Hollingsworth SJ (2004) Wearing Graduated Compression Stockings: The reality of everyday deep vein thrombosis prophylaxys Phlebology Journals 19(1): Blaivas AJ (2009) ACP Journal Club. Graduated compression stockings did not prevent deep venous thrombosis after stroke and increased skin complications. Ann Intern Med 151(8): JC4 9. doi: / Blann A (2014) Prevention and treatment of venous thromboembolism: the nurse s role in management. British Journal of Cardiac Nursing 9(11) Bowling A (2005) Quantitative social science: the survey. In: Bowling A, Ebrahim S (eds). Handbook of health research methods: investigation, measurements and analysis. Open University press, Berkshire Byrne B (2001) Deep vein thrombosis prophylaxis: the effectiveness and implications of using below-knee or thigh-length graduated compression stockings. Heart Lung 30(4): doi: /mhl Camporese G, Bernardi E, Prandoni P et al (2008) Low-molecular-weight heparin versus compression stockings for thromboprophylaxis after knee arthroscopy: a randomized trial. Ann Intern Med 149(2): CLOTS (Clots in Legs Or stockings after Stroke) Trial Collaboration (2010) Thigh-length versus below-knee stockings for deep venous thrombosis prophylaxis after stroke: a randomized trial. Ann Intern Med 153(9): doi: / Cohen AT, Skinner JA, Warwick D, Brenkel I (2007) The use of graduated compression stockings in association with fondaparinux in surgery of the hip. A multicentre, multinational, randomised, open-label, parallel-group comparative study. J Bone Joint Surg Br 89(7): doi: / X.89B Delavenne X, Zufferey P, Nguyen P et al (2012) Pharmacokinetics of fondaparinux 1.5 mg once daily in a real-world cohort of patients with renal impairment undergoing major orthopaedic surgery. Eur J Clin Pharmacol 68(10): doi: /s Department of Health, Chief Medical Officer (2007) Report of the independent expert working group on the prevention of venous thromboembolism (VTE) in hospitalised patients. q27rv3u (accessed 26 June 2015) Garwood CL, Gortney JS, Corbett TL (2011) Is there a role for fondaparinux in perioperative bridging? Am J Health Syst Pharm 68(1): doi: /ajhp Gee E (2011) Anti-embolism stockings. Nurs Times 107(14): 18 9 Goldhaber SZ (2010) Risk factors for venous thromboembolism. Journal of the American College of Cardiology 56(1):1-7 Hameed MF, Browse DJ, Immelman EJ, Goldberg PA (2002) Should kneelength replace thigh-length graduated compression stockings in the prevention of deep-vein thrombosis? S Afr J Surg 40(1): 15 6 Hayes JM, Lehman CA, Castonguay P (2002) Graduated compression stockings: updating practice, improving compliance. Medsurg Nurs 11(4): House of Commons Health Committee (2005) The prevention of venous thromboembolism in hospitalised patients. (accessed 26 June 2015) Ingram JE (2003) A review of thigh-length vs knee-length antiembolism stockings. Br J Nurs 12(14): doi: /bjon Nicolaides AN, Fareed J, Kakkar AK et al (2006) Prevention and treatment of venous thromboembolism. International Consensus Statement (Guidelines according to scientific evidence). Int Angiol 25: com/oaycya4 (accessed 26 June 2015) Jamieson R, Calderwood CJ, Greer IA (2007) The effect of graduated compression stockings on blood velocity in the deep venous system of the lower limb in the postnatal period. BJOG 114(10): doi: /j x The Joanna Briggs Institute (2008) Graduated Compression Stockings for the prevention of post-operative venous thromboembolism. Australian Nursing Journal 16(2): 31-3 Kumar DR, Hanlin E, Glurich I, Mazza JJ, Yale SH (2010) Virchow s contribution to the understanding of thrombosis and cellular biology. Clin Med Res 8(3-4): doi: /cmr MacLellan DG, Fletcher JP (2007) Mechanical compression in the prophylaxis of venous thromboembolism. ANZ J Surg 77(6): doi: /j x May V, Clarke T, Coulling S et al (2006) What information patients require on graduated compression stockings. Br J Nurs 15(5): doi: /bjon National Institute for Health and Care Excellence (2010) Venous thromboembolism in adults admitted to hospital: reducing the risk. tinyurl.com/pflowmj (accessed 26 June 2015) Noble SIR, Nelson A, Turner C, Finlay IG (2006) Acceptability of low molecular weight heparin thromboprophylaxis for inpatients receiving palliative care: qualitative study. BMJ 332(7541): doi: / bmj Rawat A, Huynh TT, Peden EK, Kougias P, Lin PH (2008) Primary prophylaxis of venous thromboembolism in surgical patients. Vasc Endovascular Surg 42(3): doi: / Rimaud D, Boissier C, Calmels P (2008) Evaluation of the effects of compression stockings using venous plethysmography in persons with spinal cord injury. J Spinal Cord Med 31(2): Roberts LN, Porter G, Barker RD et al (2013) Comprehensive VTE prevention program incorporating mandatory risk assessment reduces the incidence of hospital-associated thrombosis. Chest 144(4): doi: /chest Royal College of Nursing (2015) Preventing VTE RCN. com/o7prvdv (accessed 26 June 2015) Sajid MS, Desai M, Morris R, Hamilton G (2008) Knee-length graduated compression stockings for thromboprophylaxis in air travellers: A metaanalysis. Int J Angiol 17(3): Srinivasaiah N, Arsalani-Zadeh R, Monson JR (2012) Thrombo-prophylaxis in colorectal surgery: a National Questionnaire Survey of the members of the Association of Coloproctology of Great Britain and Ireland. Colorectal Dis 14(7): e doi: /j x Sweetland S, Green J, Liu B et al (2009) Duration and magnitude of the postoperative risk of venous thromboembolism in middle aged women: prospective cohort study. BMJ 339: b4583 Thrombosis UK (2014) Prevention. (accessed 1 July 2015) Walker L, Lamont S (2007) The use of antiembolic stockings. Part 1: a literature review. Br J Nurs 16(22): doi: / bjon Wells P, Anderson D (2013) The diagnosis and treatment of venous thromboembolism. Hematology Am Soc Hematol Educ Program 2013: doi: /asheducation Winslow EH, Brosz DL (2008) Graduated compression stockings in hospitalized postoperative patients: correctness of usage and size. Am J Nurs 108(9): doi: /01.NAJ Fundamental Aspects of Finding and Using Information Barbara Freeman and David Thompson The text will enable any student to tackle all manner of assignments with confi dence and success. Includes simple strategies to gain the information-seeking skills necessary to get you started Fundamental Aspects of Finding and Using Information A guide for students of nursing and health Barbara Freeman and David Thompson Simple and jargon-free text explaining how to access and utilise the information needed for the successful completion of undergraduate-level assignments. ISBN-13: ; 234 x 156 mm; paperback; 150 pages; publication December 2008; Order your copies by visiting or call +44(0) British Journal of Nursing, 2015, Vol 24, No

6 Copyright of British Journal of Nursing is the property of Mark Allen Publishing Ltd and its content may not be copied or ed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or articles for individual use.