The European Lung White Book

Transcription

1 [Clinical Oxygen delivery devices: exploring the options Phyllis Murphie reviews the technological innovations in longterm oxygen therapy, offering an outline of the delivery systems that are currently available in practice Phyilis Murpliie is respiratory nurse consultant, NHS Dumfries and Galioway Submined 24 November 2013; accepted for pubiication foiiowing peer review 28 November 20 i 3 Key words: Chronic obstructive puimonary disease, home oxygen services, iong-term oxygen therapy The European Lung White Book reports respiratory diseases as one of the leading causes of death worldwide, with chronic obstructive pulmonary disease (COPD) reported as the fourth most common cause of mortality (Gibson et al, 2013). COPD is defined as a chronic lung disease which is characterized by airflow obstruction that is usually progressive, not fully reversible and does not change markedly over several months (National Institute for Health and Care Excellence (NICE), 2010). Smoking has been identified as the primary cause of COPD (NICE, 2010). According to the World Health Organization (WHO) (2013), COPD is projected to become the third most common cause of mortality in Epidemiological evidence suggests that there are an estimated 3.7 million people in the UK with COPD, which is the nation's fifth largest killer disease (British Lung Eoundation (BLE), 2007). COPD is currently the second most common reason for hospitalization and one of the most costly conditions to manage in the acute care setting (BLE, 2007). At present, there are 3 million people aged 80 years and above with COPD in the UK. This figure is projected to double by 2030 and reach 8 million by 2050 (NHS, 2012). Home oxygen services in the UK The combination of an ageing population and the increase in chronic respiratory disease will undoubtedly add to the burden that the already over-stretched NHS home oxygen services face in terms of increasing numbers of people being referred for home oxygen assessment (NHS Choices, 2013). The cost of the home oxygen service in England is currently estimated at 110 million a year (NHS Improvement, 2011). As the supply of home oxygen cylinders by community pharmacies has now ceased in England, Scotland and Wales (with Northern Ireland in the transition phase), oxygen assessment and delivery services vary throughout NHS health authorities in the UK. It is therefore vital for prescribers to ensure that home oxygen services are patientcentred and cost efficient. Oxygen equipment options for home delivery have evolved in the last few decades. This has been driven by a number of factors, such as: ^ Technological innovations ^ Einancial pressures within NHS prescribing budgets ^ Increasing patient demands for lighter weight systems that facilitate longer periods away from the home environment. Oxygen prescribers need to be patientfocused when deciding which oxygen delivery modality best suits the individual's lifestyle in order to ensure that the patient is adequately oxygenated at all activity levels. This may change over time as the individual's medical condition dictates. New technologies such as self-filling delivery systems demonstrate greater independence and user satisfaction, with significant financial savings to the NHS. Long-term oxygen therapy Long-term oxygen therapy (LTOT) is currently the only known medical intervention proven to prolong survival, improve exercise tolerance and reduce hospitalization in individuals with COPD (Nocturnal Oxygen Therapy Trial Group, 1980; Medical Research Council Party, 1981; Petty and Bliss, 2000). These benefits have been shown in patients with COPD who have an arterial oxygénation level that is less than 7.3 kpa when clinically stable or between kpa with other existing comorbidities (NICE, 2010). Clinical stability is defined as the absence of exacerbation of chronic lung disease for the previous 5 weeks. Patients may also present with any one of the following symptoms (NICE, 2010): > Secondary polycythaemia > Nocturnal hypoxaemia, with oxygen saturation of arterial blood (SaO^) of less than 90% for more than 30% of the time V Peripheral oedema Pulmonary hypertension. Table 1 provides a list of patient groups that should be assessed for oxygen therapy. 124 Practice Nursing 2014,Vol 25, No 3

2 [Clinical Table I. Patient groups that should be assessed for oxygen therapy Patients with severe airflow obstruction, with FEV, <30% of predicted Patients with cyanosis Patients with polycythaemia Patients with peripheral oedema Patients with an elevated jugular venous pressure Patients with SaO, <92% FEV : forced expiratory volume SaOîi arterial blood From: National Institute for Health and Clinical Excellence, 2010 Figure I. Static oxygen concentrator Figure 2. Homefill oxygen delivery system Oxygen delivery systems The most common oxygen delivery systems that are currently available are discussed below. Static oxygen concentrators LTOT is usually provided by a stationary oxygen concentrator (Figure i).this delivery system should be used for at least 15 hours a day to achieve survival benefits. Such a therapeutic regimen can affect the ability of the user to remain active and can have a significant impact on travel away from the home environment. However, an oxygen concentrator is the most economical home oxygen delivery system. The device should be serviced by an engineer on a 3-6 monthly basis and electricity costs will be reimbursed by the individual's oxygen contractor. Devices can provide a range of oxygen flow rates of up to 9 litres/minute for other respiratory conditions, such as interstitial lung disease, where prescribed. Homefill oxygen delivery systems Homefill oxygen delivery technology is relatively new to the UK and combines an oxygen concentrator with an added reservoir system on top [Figure 2). This allows for the safe refilling of ambulatory cylinders with an integral oxygen-conserving headset. Research to date has demonstrated clinical efficacy and the potential to benefit many oxygen-dependent patients (McCoy and Bliss, 2001; Cuvelier et al, 2002; Lewarski et al, 2003; Murphie et al, 2013). This system can reduce costs for healthcare providers by eliminating the use of cylinder deliveries, allowing patients to enjoy freedom and independence with an unlimited supply of ambulatory oxygen. A cylinder with an oxygen capacity of 4.3 lb provides more than 5 hours of ambulatory time and can be refilled overnight. This system permits oxygen delivery only during the inspiratory phase, thus increasing the oxygen supply time by up to threefold and reducing oxygen wastage. For individuals who are oxygen dependent and wish to leave the house for more than 30 minutes every day, this system is more economical than continuous flow oxygen via ambulatory oxygen cylinders or liquid oxygen. A large survey of patients' views on the homefill system was conducted by Murphie et al (2013) in NHS Scotland. Out of 750 homefill users, there was a 62% response rate to the survey. Respondents reported that the system was easy to use and there was a 50% increase in time spent away from the home in those who went out 4 times or more per week. Approximately 92% of respondents selfreported improved quality of life with the homefill system, and 100% of respondents rated the quality of the service provided by the home care oxygen provider as good or better. Ambulatory oxygen cylinders Ambulatory oxygen therapy is defined as the use of oxygen during exercise and activities of daily living. It is indicated for a number of conditions, with COPD being the most common, followed by other chronic lung diseases such as (NICE, 2010): ^ Chronic severe asthma V Interstitial lung disease > Cystic fibrosis ^ Bronchiectasis V Pulmonary vascular disease > Primary pulmonary hypertension > Pulmonary malignancy. Ambulatory oxygen therapy has been shown to improve exercise tolerance and quality of life in people with moderate to severe COPD (Eaton et al, 2002; Ram and Wedzicha, 2002). However, the evidence base for its use requires further study to establish the long-term benefits of ambulatory oxygen in subgroups of patients with varying degrees of hypoxaemia, both at rest and exerciseinduced. Moore et al (2011) concluded that in patients with COPD and dyspnoea who do not have resting hypoxaemia, ambulatory oxygen had no beneficial effect in terms of dyspnoea, quality of life or function. Ambulatory oxygen therapy can currently be prescribed in three groups of patients. The indications for this are (NICE, 2010): > Patients on LTOT who are mobile and who need or are able to leave the home on a regular basis ^ Patients on LTOT who are housebound and unable to leave the home unaided, but who may use ambulatory oxygen for short, intermittent periods V Patients without chronic hypoxaemia, but who show evidence of arterial oxygen desaturation on exercise. 5 s Lightweight cylinders {Figure 3) last for I approximately 3 hours at a fiow rate of < 2 litres/minute. Thus, if an individual wishes 5 to go out for in excess of 3 hours or if they 126 Practice Nursing 2014, Vol 25, No 3

3 require a flow rate that is greater than 2 litres/minute, they will have to take more than one cylinder with them, which would be a difficult task for many patients. Ambulatory oxygen therapy can allow more freedom for individuals with chronic lung disease, although it requires a certain amount of planning and coordination to facilitate a day away from home. Patients will require the lightest cylinder that can operate for the longest period of time to allow activities of daily living away from the home environment. Oxygen conserving devices Oxygen conserving devices emerged in the early 1980s to improve the efficiency of ambulatory oxygen delivery. They were developed in an effort to improve the portability of ambulatory oxygen delivery by reducing the litre flow, thereby enabling patients to use either a smaller and lighter system or a standard system for longer time periods. The efficacy of oxygen conserving devices have been reported in the literature over the last 20 years as advantageous in extending the life of oxygen cylinders (Garrod et al, 1999; Langenhof and Fichter, 2005). Oxygen conserving devices (Figure 4) work by sensing the start of the user's inspiratory effort and instantly deliver a dose of oxygen at the beginning of the inhalation. Any oxygen flowing during exhalation, which constitutes 60-70% of the respiratory cycle as well as the last 30% of inhalation, fills anatomic dead space and is wasted (Garrod et al, 1999; Murphie et al, 2008). Thus, if only 15-20% of the respiratory cycle effectively delivers fresh oxygen to the alveoli for participation in gas exchange, it would appear logical to try to restrict oxygen delivery to early inhalation. In selected and appropriately assessed patients, oxygen conserving devices can extend the life of oxygen cylinders, thus reducing the overall consumption and/or costs related to prescribing. These devices can also increase the time spent away from the home environment (Murphie et al, 2008). device. Transportable oxygen concentrators can be used for travel away from the home and many transportable devices are approved by the civil aviation authority although airlines regulations vary. Portable oxygen concentrators Portable oxygen concentrator technology is evolving and many patients purchase their own devices as these offer more freedom and the ability to leave the home for extended period (Figure 6). However, these systems are not available on NHS prescription. Portable oxygen concentrators can deliver continuous flow and pulsed dose oxygen delivery. These systems are lighter in weight than transportable concentrators but their size and delivery characteristics vary depending on the model and/or manufacturer. Liquid oxygen Liquid oxygen is prescribed where there is a requirement for the use of large amounts of portable and/or ambulatory oxygen or if a higher flow of oxygen is prescribed. Liquid oxygen from a tank is decanted into a vacuum Figure 3 (above, left). Ambulatory oxygen cylinder Figure 4 (above, right). Oxygen conserving device Figure 5 (below, left). Transportable oxygen concentrator Figure 6 (below, right). Portable oxygen concentrator Transportable oxygen concentrators Transportable oxygen concentrators (Figure 5) are portable delivery systems that provide continuous oxygen flow and pulsed dose oxygen delivery. These devices have internal batteries that can last between 2-4 hours depending on the oxygen setting of the Practice Nursing 2014,Vol 25, No 3 127

4 \_CUnical KEY POINTS > Oxygen equipment options for home delivery have evolved over the last fev/ decades > Practice nurses need to have a clear understanding of the delivery systems currently available to ensure that oxygen services are clinically-led and patient-centred > Patients must have access to oxygen delivery systems that are adaptable to their needs inside and outside the home > New oxygen delivery technologies allow more freedom for users to leave the home for longer periods flask in the patient's home (Figure 7). The tank is replaced with a refill by the home oxygen supplier when empty. This system is dependent on home delivery of refill containers, usually on a fortnightly basis. Liquid oxygen provision is financially more costly than other oxygen delivery modalities. Liquid oxygen tanks must be stored in a well-ventilated room, garage or shed. It is important to ensure that the tanks are not placed near items that are likely to catch fire. Portable liquid oxygen flasks come in various sizes and can be operated on a continuous flow and pulsed dose setting with internal or external conserving devices. Conclusions New oxygen delivery technologies such as the homefiu combination of integrated LTOT supply and self-fiuing ambulatory oxygen cylinders offer a significant benefit to the NHS in terms of delivering services that are cost effective and should be made more widely available across the UK. The Scottish experience of homefill in a large number of service users has been well evaluated, with positive patient reported outcomes such as extended time away from the home environment and significant financial savings (Murphie et al, 2013). To achieve the vision of the home oxygen service (NHS Improvement, 2011), clinicians who prescribe home oxygen therapy need to have a clear understanding of the various oxygen delivery modalities in order to provide a clinically-led and patient-focused home oxygen service. Those requiring LTOT must have access to clinically effective and cost efficient oxygen delivery equipment that is adaptable to their needs inside and outside the home. Lighter weight cylinders that can operate for longer periods of time which allow users to leave the home for extended periods would benefit future service users. This could be the next challenge for manufacturers of home oxygen ambulatory systems. Conflict of interest: The author was a member of the Scottish Government Health Department Domicihary Oxygen Review in NHS Dumfries and Galloway were part of a national trial on the Homefill system in NHS Scotland. The author has received sponsorship from GlaxoSmithKline, Resmed, Chiesi and Dolby Vivisol to attend international conferences. References Figure 7. Portable liquid oxygen flask 128 British Lung Foundation (2007) Invisible lives: chronic obstructive pulmonary disease (COPD) finding the missing milhons. (accessed 6 December 2013) Guvelier A, Nuir JF, Ghakroun N et al (2002) Refillable oxygen cylinders may be an alternative for ambulatory oxygen therapy in COPD. Chest 122(2): Eaton T, Garrett JE, Young P et al (2002) Ambulatory oxygen improves quality of life of COPD patients: a randomised controlled study. Eur RespirJ 20(2): Garrod R, Bestall J, Paul E, Wedzicha J (1999) Evaluation of pulsed dose oxygen delivery during exercise in patients with severe chronic obstructive pulmonary disease. Thorax 54(3): Gibson JG, Loddenkemper R, Sibille Yves, Lundback B, eds (2013) European Lung White Book. European Respiratory Society, Lausanne Langenhof S, Fichter J (2005) Comparison of two demand oxygen delivery devices for administration of oxygen in COPD. Chest 128(4): Lewarski J, Mikus J, Andrews G, Chatburn R (2003) A clinical comparison of portable oxygen system: continuous flow compressed gas vs. oxygen concentrator gas delivered with an oxygen conservering device. Respir Care 48(11): 1115 McCoy R, Bliss P (2001) Evaluation of the Venture Homefill II oxygen system during activities of daily living. (accessed 6 December 2013) Medical Research Council Party (1981) Long-term domiciliary oxygen therapy in chronic hypoxic cor pulmonale complicating chronic bronchitis and emphysema. Report of the Medical Research Council Working Party. Lancet 1(8222): Moore RP, Berlowitz DJ, Denehy L et al (2011) A randomised trial of domiciliary, ambulatory oxygen in patients with COPD and dyspnoea but without resting hypoxaemia. Thorax 66(1): doi: /thx Murphie P, Little S, Gysin J, Rafferty P (2008) Oxygen conserving devices potential for financial savings with improved quality of life? Poster presentation at the European Respiratory Society Annual Congress, Berlin, 7 October 2008 Murphie P, Wilson M, Small I, McGhee W, Laird S, Little S (2013) A national homefill survey. Poster presentation at the Scottish Respiratory MCN Learning Forum, Stirling, 6 September 2013 National Institute for Health and Care Excellence (2010) Chronic obstructive pulmonary disease: management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update). NICE clinical guidelines (accessed 6 December 2013) NHS (2012) NHS atlas of variation in healthcare for people with respiratory disease: reducing unwarranted variation to increase value and improve quality. (accessed 6 December 2013) NHS Choices (2013) Home oxygen treatment, Introduction.aspx (accessed 6 December 2013) NHS Improvement (2011) Home oxygen service assessment and review good practice guide, tinyurl.com/12p7syx (accessed 6 December 2013) Nocturnal Oxygen Therapy Trial Group (1980) Continuous or nocturnal oxygen therapy in hypoxemic chronic obstructive lung disease: a clinical trial. Nocturnal Oxygen Therapy Trial Group. Ann Intern Med 93(3): Petty TL, Bliss PL (2000) Ambulatory oxygen therapy, exercise, and survival with advanced chronic obstructive pulmonary disease (the Nocturnal Oxygen Therapy Trial revisited). Respir Care 45(2): Ram FS, Wedzicha JA (2002) Ambulatory oxygen for chronic obstructive pulmonary disease. Cochrane Database Syst Reu 2: CD World Health Organization (2013) Burden of COPD. index.html (accessed 6 December 2013) Practice Nursing 2014, Vol 25, No 3

5 Copyright of Practice 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.