Meeting oxygen needs in Africa: an options analysis from the Gambia

763Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Meeting oxygen needs in Africa: an options analysis from the Gambia Stephen RC Howie,a Sarah Hill,b Augustine Ebonyi,a Gautam Krishnan,c Ousman Njie,d Momodou Sanneh,a Mariatou Jallow,e Warren Stevens,f Kevin Taylor,c Martin W Weber,g Pamela Collier Njai,h Mary Tapgun,h Tumani Corrah,h Kim Mulholland,f David Peel,i Malick Njie,e Philip C Hill j & Richard A Adegbola a Objective To compare oxygen supply options for health facilities in the Gambia and develop a decision-making algorithm for choosing oxygen delivery systems in Africa and the rest of the developing world. Methods Oxygen cylinders and concentrators were compared in terms of functionality and cost. Interviews with key informants using locally developed and adapted WHO instruments, operational assessments, cost-modelling and cost measurements were undertaken to determine whether oxygen cylinders or concentrators were the better choice. An algorithm and a software tool to guide the choice of oxygen delivery system were constructed. Findings In the Gambia, oxygen concentrators have significant advantages compared to cylinders where power is reliable; in other settings, cylinders are preferable as long as transporting them is feasible. Cylinder costs are greatly influenced by leakage, which is common, whereas concentrator costs are affected by the cost of power far more than by capital costs. Only two of 12 facilities in the Gambia were found suitable for concentrators; at the remaining 10 facilities, cylinders were the better option. Conclusion Neither concentrators nor cylinders are well suited to every situation, but a simple options assessment can determine which is better in each setting. Nationally this would result in improved supply and lower costs by comparison with conventional cylinders alone, although ensuring a reliable supply would remain a challenge. The decision algorithm and software tool designed for the Gambia could be applied in other developing countries. Une traduction en français de ce résumé figure à la fin de l’article. Al final del artículo se facilita una traducción al español. .ةلاقلما هذهل لماكلا صنلا ةياهن في ةصلاخلا هذهل ةيبرعلا ةمجترلا a Bacterial Diseases Programme, Medical Research Council Laboratories, PO Box 273, Banjul, Gambia. b Department of Public Health, University of Otago, Wellington, New Zealand. c Biomedical Engineering Department, Medical Research Council Laboratories, Banjul, Gambia. d Integrated Management of Childhood Illness Programme, Department of State for Health and Social Welfare, Banjul, Gambia. e Department of State for Health and Social Welfare, Banjul, Gambia. f London School of Hygiene and Tropical Medicine, London, England. g Department of Child and Adolescent Health, World Health Organization, Geneva, Switzerland. h Clinical Services Department, Medical Research Council Laboratories, Banjul, Gambia. i Ashdown Consultants, Uckfield, East Sussex, England. j Centre for International Health, University of Otago, Dunedin, New Zealand. Correspondence to Stephen RC Howie (e-mail: showie@mrc.gm). (Submitted: 30 August 2008 – Revised version received: 24 February 2009 – Accepted: 6 April 2009 – Published online: 24 August 2009 ) Introduction Acute respiratory infection, principally pneumonia, remains the leading cause of death in young children worldwide.1–3 Case management of pneumonia is a key component of the WHO Integrated Management of Childhood Illness strategy and is integral to the achievement of the fourth UN Millen- nium Development Goal: reducing under-5 mortality by two-thirds by 2015.4 WHO guidelines for the management of pneumonia include antibiotic therapy, appropriate use of oxygen and general supportive care. Oxygen is needed to treat hypoxaemia, a life-threatening feature of very severe pneu- monia resulting from impaired lung function. Medical oxygen, which is potentially life-saving, is in lim- ited supply in the developing world, although the extent and nature of the problem are not well documented.5 A situational analysis has shown that in the Gambia most health facilities have inadequate oxygen availability and that the factors that are important for ensuring oxygen supplies differ between facilities.6 Oxygen concentrators have been proposed as an answer to the high cost and logistical problems associated with oxy- gen cylinders, the traditional method of supply.7 However, there is a risk that the technology might be misapplied, compromising care.8 The suitability of concentrators for the developing world is still in question, and a realistic appraisal of the role of concentrators in different contexts is needed, along with user-friendly guidance to assist decision-making. In this report, we analyse the options available, suggest a decision-making algorithm and present a software tool we have produced to analyse options and costs in a range of dif- ferent contexts. Methods A health needs assessment framework was used to define is- sues that surround oxygen treatment in the Gambia and the options for improving it.9–11 In this study we evaluated the two supply options, cylinders and concentrators, in terms of 764 Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Research Meeting oxygen needs in Africa Stephen RC Howie et al. their cost, how well they work and their sustainability. Functionality assessment We first analysed the functionality of cylinders and concentrators. Data were collected in 2004–2007 and analysed in 2005–2008. We used semi-structured interviews with two instruments: the first was developed by one of the authors (SEH) specifi- cally for a case study of failed oxygen concentrators in the Gambia,6 and the other was adapted and validated by one of the authors (SEH) for a local study of oxygen use8 from a WHO health fa- cility assessment tool. Interviews were undertaken throughout the Gambia with health-care staff, administra- tors, policy-makers and others with relevant knowledge. Details of the instruments, interviewees and other aspects of methods used are described elsewhere.6,8 In addition, we collated the international operational experi- ence of our multi-disciplinary team of investigators, assessed the operational experience gained in the Gambia so far and reviewed others’ published experi- ence. The findings of the functional as- sessment were incorporated, along with the cost analyses described below, into a decision algorithm. Table 1. Detail of capital cost and running cost data used for cost modelling assessment of Gambian health facilities, 2004 Category and description Cost in US$, or power consumption Notes Oxygen concentrator Airsep NewLife Intensity 1100.00 2008 cost direct from manufacturer supplied to Medical Research Council, the Gambia (including shipping) 4-way flow-splitter 175.00 2008 cost direct from manufacturer Cylinder 6 000 litres 37.51 March 2007 cost, Banjul Oxygen Delivery 11.00 per cylinder 2004 cost to transport to Bansang. Transport to Royal Victoria Teaching Hospital, Banjul, free Regulator-flowmeter set 188.00 January 2008 cost Oxylitre, United Kingdom Hospital piping system 11 000.00 20-bed 6-cylinder bank system based on 2001 costs at Medical Research Council hospital Power National grid 0.40 per kWh November 2007 cost, NAWEC, the Gambia 4-kVA generator 3000.00 January 2008 cost, Just Generators, United Kingdom Diesel fuela 1.06 per litre November 2007 duty-free import price (applicable to government services) kVa, kilovolt-ampere; kWh, kilowatt-hour; NAWEC, National Water and Electricity Company; US$, United States dollars. a Fuel consumption of generator: 0.5 litres per 4 kVA output. Power rating of concentrator: 0.4 kW. Cost modelling To provide comparative costs in differ- ent contexts, we broke down and costed each option by using the ingredients approach and applied a decision- analytic model to frame the alternative components,12,13 taking into account capital and running costs, the scale of consumption and the context. We constructed a decision algorithm to identify the most cost-effective option for a range of circumstances. These re- sults were incorporated into an options analysis tool developed on Microsoft Access software (Microsoft Corpora- tion, Redmond, WA, United States of America), and the tool was applied to data from a previous situational analy- sis of Gambian health facilities.6 We used costs in 2007 and exchange rates of 22.66 dalasi per United States dollar (US$) and US$ 1.977 per United King- dom pound on 24 December 2007.14,15 Capital and running costs used in the model are detailed in Table 1. The WHO recommendation of one concentrator to every 10–15 beds (supplying up to four children simultaneously by use of a flow-splitter) was followed, with one backup concentrator added. Costs for five regulator-flowmeter sets per 10–15 beds (for cylinders to supply up to four children at a time plus a backup cylinder) were included. Expected lifespans of 5 years were assumed for concentrators, generators and regulator-flowmeter sets. Where a concentrator would be pow- ered by spare capacity from a facility’s already-operating generator (typically 40 kilovolt-amperes [kVA]) no power cost was included. Where reliable power supplies were of mixed grid and generator origin, the costs were taken as grid-power costs. We rated cylinder leakage at 10% for new well-maintained equipment con- nected directly to the patient, 50% for old poorly-maintained equipment connected directly to the patient, and 80% for old poorly-maintained equipment connected to a piped delivery system. Oxygen re- quirements were estimated based on local rates of severe hypoxaemia (oxygen satu- ration < 90%) among children admitted to hospital (6%)16 and average local durations (3 days) and flow rates (1.5 L/ min) of oxygen treatment (unpublished data). We performed sensitivity analyses based on worse-than-expected equipment lifespans, variations in power availability and different levels of cylinder leakage.17,18 To provide directly-measured cost- ing data that could be compared with national modelled data, we undertook a prospective study at the 42-bed Medical Research Council Hospital between 23 January and 4 April 2006. The hospital was supplied mainly with cylinder oxygen through a piped system 765Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Research Meeting oxygen needs in AfricaStephen RC Howie et al. Table 2. Comparison of the characteristics of oxygen cylinders and oxygen concentratorsa Characteristics Cylinders Concentrators Capital cost High when regulator and flowmeter costs included High Running cost High, particularly if leakage is significant Low if power is inexpensive High if power is expensive Ease of use Some training required Considerable training required Reliability Good Good on selected models Physical robustness Good Fair Regular maintenance Needed Needed Technical repairs Needed (e.g. for regulators, to minimize leakage) Needed (maintenance staff require specialized training) Electricity Not needed Needed Continuity of oxygen delivery Liable to run out Good as long as power is available Portability Poor for large cylinders Good Supply system Transport needed Ordering needed Transport not needed Ordering not needed a Table adapted from the WHO Acute Respiratory Infections Programme oxygen handbook.19 installed in 2001, with back-up from four concentrators (model DeVilbiss 515, DeVilbiss Healthcare, Somerset, PA, USA). Hospital policy was to give oxygen when oxygen saturation was below 93%, which would be expected to result in higher consumption than if the standard cut-off of < 90% were used. Costs were measured over two consecutive periods: 41 days of supply predominantly by cylinders (period 1) and 45 days of supply predominantly by concentrators (period 2). Costs were taken from payment records. The capital cost of the concentrators was calculated as the proportion of the purchase cost equivalent to the number of hours used divided by the projected 40 000-hour running lifespan (ap- proximately 5 years of continuous use) of an individual unit. The concentrator unit cost was US$ 1763, including shipping; power costs per kilowatt- hour (kWh) were US$ 0.19 from the generator and US$ 0.28 from the grid; oxygen cylinders cost US$ 30.18 per 6000-L cylinder, including delivery; the cylinder piping cost including in- stallation was US$ 16 663. The amount of oxygen consumed was measured by regular recording at the bedside and by the number of cylinders used. The metred running time of the concen- trators was also recorded. Costs were represented in US$ based on exchange rates applicable at the time costs were incurred.14,15 Ethical approval for the study was given by the Gambia Government Medical Research Council Joint Ethics Committee (SCC/EC974). Results Functionality assessment The advantages and disadvantages of cylinders and concentrators are shown in Table 2. The interview findings have been previously reported.6,8 Cylinders were regarded by most users as relatively simple to operate but hard to move, likely to run out without warning and difficult to resupply. Respondents were generally less familiar with operating oxygen concentrators, although they regarded them as easier to move around. They felt, however, that the need for a continuous power supply and the tendency of concentrators to break down were problematic. Both cylinders and concentrators were regarded as ex- pensive, but cylinders were regarded as especially costly by administrators. The investigators’ operational ex- perience supported local user observa- tions. Some additional observations were relevant. Effective maintenance and monitoring mechanisms are crucial to success. The Gambia is unlike some countries in that all major health facili- ties are on or near main roads, so cyl- inder transport is potentially workable if reliable arrangements can be made. For the sake of usability there should be one main method of supply in each facility, with an alternative means of supply as a backup. While solar power has several advantages, including inde- pendence from fossil fuels, the careful daily maintenance required for systems powerful enough to run concentrators make the latter currently impractical for most health facilities in the Gambia and other developing countries.20 An engineering assessment of the piped oxygen system at the Medical Research Council Hospital by two of us (DP and KT) showed leakage of around 70% based on the cylinders used and the oxygen delivered over a 4-day period. Most leakage was from the cylinder heads. The cylinder system at the Royal Victoria Teaching Hospital in Banjul also had significant leakage. Cylinder leakage has been repeatedly observed in the Gambia from both free-standing bedside cylinders and piped systems; there are anecdotal reports that problems are greater with older equipment and piped systems. The extent of cylinder leakage was estimated to be 10–80% depending on the kind of system used (piped or direct from the cylinder), the quality of the equipment and the stan- dard of maintenance. Global experience in comparing the functionality of concentrators and cyl- inders is summarized in WHO’s oxygen therapy handbook.19 Table 2 represents a refinement of this experience based on the findings of the present study. Notable differences in the table we used compared to the WHO handbook are that cylinder capital costs approach the high costs of concentrators when regulator-flowmeter costs are included; concentrator running costs are high if power costs are high, and training and maintenance are important for cylinders as well as concentrators. Cost modelling and decision algorithm Fig. 1 shows an algorithm for deter- mining the most suitable cost-effective option for the main oxygen supply. Where the power supply is reliable, oxygen concentrators are preferable both in terms of cost and convenience; 766 Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Research Meeting oxygen needs in Africa Stephen RC Howie et al. Fig. 1. Algorithm for deciding the most suitable main oxygen supply method for health facilities in the Gambia, 2004 Yes No Cylinder transport workable? Power reliable? Yes No Feasible to make centre’s existing power reliable? No Yes Cylinders?Concentrators Dedicated power supply where creating a reliable power supply is not feasible or cost-effective, the practicality of cylinder transport should be considered. If cylinder transport is workable, then cylinders are preferable. If cylinder delivery is problematic, then a concentrator with a dedicated power supply, such as a small generator, is preferred. If neither option is possible, a reliable oxygen supply cannot be en- sured and hypoxaemic patients should be transferred to another facility, if possible. Table 3 shows the results of model- ling based on 2004 data from health fa- cilities in the Gambia, with costs given for cylinders and for concentrators powered from different sources. With power defined as reliable if available for an average of at least 20 hours daily, two of the 12 facilities were suitable for concentrators, whereas the remaining 10 were better suited to cylinders as the pri- mary source of supply because they had unreliable power supplies and reasonable road access for the delivery of cylinders. The estimated average annual cost of an adequate oxygen supply for all facilities was US$ 152 747 using cylinders, US$ 76 485 using the supply source suggested by the decision algorithm, and US$ 18 742 using concentrators if all facilities had a continuous grid power supply. The costs of running concentrators powered by a small generator compared favour- ably with the cost of a cylinder supply for all facilities. Fig. 2 shows the results of a sensi- tivity analysis that models the effect of varying lifespans of oxygen concentra- tors, different levels of cylinder leakage and varying constancy of grid power supply on the cost of oxygen in an average-sized health centre with aver- age oxygen requirements. The amount of cylinder leakage had a large effect on cost, whereas concentrator lifespan had little effect. Furthermore, con- centrators were better than cylinders with average leakage in facilities with grid power for more than 18 hours per day (where power gaps are bridged by the facility’s existing generator), and in large facilities with power for more than 12 hours daily (data not shown). The results of the sensitivity analysis for small facilities resembled those obtained for average-sized facilities, the only exception being that early concentra- tor failure significantly undermined the cost-effectiveness of concentra- tors because low usage makes capital costs proportionately higher (data not shown). Analysis of the combined use of a concentrator and a small generator showed that for an average-sized facility, the cost advantage compared to cylin- ders disappeared when concentrator lifespan decreased from 5 years to 1 year (data not shown). Costing study The costs incurred during cylinder and concentrator use are summarized in Table 4. Costs per 1000 litres of oxygen were US$ 4.80 for the cylinder- supplied period and US$ 0.84 for the concentrator-supplied period, compared to US$ 6.56 and US$ 0.86, respectively, for modelled costs in a 42-bed hospital with no cylinder leak- age (leakage was fixed before study, see below) and an estimated twice-normal consumption as a result of the Medical Research Council Hospital’s higher treat- ment cut-offs.16 These costs were broadly similar, and the differences mainly reflected historical differences in item costs, exchange rates and concentrator use in the cylinder-supplied period (Table 4). During the cylinder-supplied period, concentrator backup was re- quired for 2 days (a weekend) because of a delay in cylinder delivery, despite the proximity of the hospital to the sup- plier (less than 10 km on good roads). Other times, concentrators were used for convenience where piped cylinder supply outlets were not close to the bed. Dur- ing the concentrator-supplied period, cylinders were used on 1 day because of an oversight. There were no failures of concentrator supply that necessitated the use of cylinders, because the hospital had a reliable power supply sourced 52% of the time from an 850-kVA generator and 48% of the time from the national grid, and there were no concentrator breakdowns. Oxygen usage was twice as high in the concentrator-supplied period because the patients in this pe- riod required more oxygen, on average, than in the cylinder-supplied period. The recorded amount of cylinder oxygen delivered to patients at the bedside was similar to the amount measured by cyl- inder consumption (187 749 L versus 168 000 L, respectively), which indi- cates successful repair of the cylinder system after the previously mentioned leak was detected. 767Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Research Meeting oxygen needs in AfricaStephen RC Howie et al. Discussion In this article we analyse options for oxygen provision in Gambian health facilities and propose a decision algo- rithm to guide the choice between con- centrators and cylinders as the main supply source at the facility level. We have developed an options assessment tool that allows detailed comparisons of the costs of currently available op- tions, and have used this to model costs in health facilities throughout the Gambia. We have shown that these costs are consistent with full direct cost measurements in one facility. Concentrators have cost advantages where the power supply is reliable, whereas cylinders currently appear to be the most workable cost-effective choice where power is not reliable and where cylinder transport is workable. Cylinder leakage, a potentially fixable drawback, significantly affects overall costs, whereas premature concentra- tor failure or other causes of inflated capital costs modestly affect costs in average-sized and large facilities. Data from all 12 government hospitals and major health centres in the Gambia Table 3. Decision analysis, estimated oxygen requirements and comparative costs in Gambian health facilities, 2004 Health facility Estimated annual oxygen requirement (million L) Decision analysis best main supply option Cost analysis, in US$ Cost per 1000 L Cost per year Concen- trators and grid power Cylinders Concen- trators and large generator (running when existing power not on) Concen- trators and small generator (running when existing power not on) Best option Cylinders 24-hour grid power and con- centrators Royal Victoria Teaching Hospital 2.451 Concentrators 1.83 31.85 ND ND 4 485 78 064 4 485 Basse 0.216 Concentrators 5.32 17.74 ND ND 1 149 3 832 1 149 Brikama 1.029 Cylinders 1.83 16.35 15.20 2.55 16 824 16 824 1 883 Bansang 0.746 Cylinders 3.15 16.83 21.00 4.13 12 555 12 555 2 350 Serekunda 0.650 Cylinders 2.56 12.79 44.89 6.12 8 314 8 314 1 664 Soma 0.566 Cylinders 3.13 16.77 45.47 6.82 9 492 9 492 1 772 Essau 0.472 Cylinders 2.86 16.57 45.17 6.76 7 821 7 821 1 350 AFPRC Hospital 0.428 Cylinders 3.56 19.96 45.89 7.60 7 259 7 259 1 524 Fajikunda 0.379 Cylinders 3.12 16.35 45.49 7.34 4 927 4 927 1 182 SJ Bwiam 0.116 Cylinders 6.18 17.79 48.63 13.99 2 064 2 064 717 Kuntaur 0.087 Cylinders 7.65 18.33 50.24 17.20 1 595 1 595 666 Total 76 485 152 747 18 742 AFPRC, Armed Forces Provisional Ruling Council; ND, not determined (not relevant according to findings from the situational analysis); US$, United States dollars. indicated that concentrators were probably the better main supply source for just two of them, the largest hos- pital being one such centre, whereas cylinders were likely to be better for the rest. We estimated the cost of an improved oxygen supply at all facilities to be one-half the cost of conventional cylinders alone. Published reports on the benefits of oxygen concentrators are posi- tive.7,20–29 Nevertheless, the limitations of this body of literature should be considered. The most comprehensive work in this area has been led by MB Dobson.7,23,25,26 His careful 1991 re- port, which modelled costs in three sizes of hospital in Papua New Guinea, predicted a saving of 25%–75% with concentrators compared to cylinders, but did not include transport costs and did not address operational feasibility issues in much detail.25 A seminal 1996 paper on a field trial in Egypt showed that concentrators could succeed on a large scale when introduced with an appropriate programme of techni- cal support and staff training.23 The limitations of this study were its short duration (1 year) and the questionable generalizability of its findings, given Egypt’s atypically good infrastructure. No report of the long-term outcome of this project has been published. The largest-scale introduction of con- centrators reported to date, for use in anaesthesia, occurred in Malawi in 1987.29 The report notes that all units “worked according to specifica- tion” over 26 months, though it is not clear how much need there was for the comprehensive technical back-up that had been put in place. Dobson reported that in a 10-year audit in Ma- lawi, 90% of concentrators were “still in use”.7 Four publications reported experiences, all essentially positive, of portable concentrator use for periods ranging from 3 to 6 years, although on a small scale.21,22,27,30 All but one of these studies were confined to a single facility, the exception being a recent report from Malawi in which one concentrator was supplied to each of five district hospitals.30 We found only one report of a single large oxygen con- centrator and piping system supplying an entire hospital. The system, in a Ghanaian teaching hospital, incorpo- rated an oxygen reservoir and backup 768 Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Research Meeting oxygen needs in Africa Stephen RC Howie et al. Fig. 2. Average annual cost of providing oxygen for paediatric patients in an average-sizeda hospital or major health centre, per daily hours of grid power available,b concentrator lifespan and level of leakage of oxygen cylinders, the Gambia, 2004 0 Co st , i n US $ 0 Average hours per day grid power available Concentrator lifespan 1 year Concentrator lifespan 5 years Cylinders 80% leak Cylinders 50% leak 35 000 30 000 25 000 20 000 15 000 10 000 5 000 4 8 12 16 20 24 Cylinders 10% leak kVa, kilovolt-ampere. a “Average-sized” is defined here as having 15 paediatric beds and an estimated annual oxygen requirement of 0.5 million litres, 1286 patient-years and 5556 concentrator-hours. b The balance in power requirement was met with a 40-kVA generator (usually present in Gambian facilities). cylinders, and broke down only twice in 4 years.31 We know of only one report of concentrator failure on a significant scale (a donation of over 20 second-hand units electrically incom- patible with the local power supply), but it is likely that publication bias has prevented other negative findings from coming to light.8 On the basis of this literature it would be unwise to assume that concentrators will do well in every situation. Although few studies have identified or quantified the problem of cylinder leakage in the developing world,32 the experience in this study, borne out by what we have observed in other settings, suggests that this problem should not be ignored. The extent of this problem in different settings and with different equipment combinations should be the focus of future studies. This study has not dealt with the important issue of the efficient use of oxygen, which will affect service costs regardless of the supply method used. Training and monitoring are needed to ensure that all who need oxygen receive it, and that it is not wasted on those who do not. Pulse oximetry is the best avail- able means of detecting hypoxaemia, and the more widespread use of this diagnos- tic technique is important to assist effi- cient oxygen usage.33 The costs associated with initiation, training and monitoring, which are important components of any oxygen delivery programme, have not been included in this analysis. Recent work in Papua New Guinea showed that these costs amounted to an additional sum representing approximately 50% of start-up costs.34 The costs for high-level engineering maintenance of either sup- ply source have not been included, as is pragmatically consistent with a context where repairs tend to be done inexpen- sively with locally-available expertise, or not at all.8 No matter what oxygen delivery system is implemented, in a resource- limited setting like the Gambia it will be vulnerable to breakdown and inter- ruption of supply. Making an appropri- ate choice between cylinders and con- centrators is important but does not, on its own, ensure a sustainable supply. To succeed, a programme must have the support of key decision-makers, fit well with local health policy and have a secure funding mechanism. Important factors such as the reliability of the power supply and cylinder transport can fluctuate markedly over time, so reliable operational arrangements must be made for backup supplies, effective monitoring and coping with situational changes. The vulnerability of available methods of supply underlines the po- tential, as well as the need, for robust new technology to transform the field. In the Gambian context as in many oth- ers, the financial sustainability of both sources of oxygen is subject to fluctua- tions in the cost of energy, chiefly of fos- sil fuels, which are necessary for power production both for the national grid and for generators. The development of reliable power sources that are not dependent on fossil fuel would be a sig- nificant advance. Although refrigerators have been successfully solar-powered in developing countries, the output required for concentrators is of a much higher order and the technology is not sufficiently robust for this at present. A recent study in Papua New Guinea showed a 35% reduction in inpatient mortality from pneumo- nia after the introduction of reliable oxygen supplies used appropriately.34 This is the only such measurement of impact available. Although we do not know if these findings would apply in the Gambian setting, it is informative to consider the benefit and cost that would result if it did. According to local health centre data, in 2004 only 79 pneumonia deaths were recorded, a likely underestimate resulting from misclassification and incomplete re- cording. Some of the patients prob- ably received oxygen, although even in centres where oxygen supplies were reliable, pulse oximetry was rarely avail- able to confirm the need for treatment. If we assume that the number of deaths not recorded offsets the number of deaths among patients who died despite having received oxygen, a 35% reduc- tion in mortality would save 28 lives 769Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Research Meeting oxygen needs in AfricaStephen RC Howie et al. Table 4. Oxygen delivered and consumed and comparison of costs incurred by delivering oxygen primarily with cylinders (period 1) or concentrators (period 2) at the Medical Research Council Hospital, Fajara, the Gambia, 2004 Period 1a Period 2b No. of patients 20 18 Oxygen consumed, in L Oxygen delivered from cylinders 181 896 2 880 Oxygen delivered from concentrators 37 575 443 746 Total 219 471 446 626 Concentrator hours 325 1 885 Costs, in US$ Concentrator capital costsc 14.32 83.08 Concentrator running costsd 30.31 175.84 Cylinder piping capital costse 93.35 102.46 Cylinder running costs f 914.94 14.49 Total 1052.92 375.87 Cost per 1000 L 4.80 0.84 Adjusted cost per average patient during each period (41 days in Period 1, 45 days in Period 2)g 74.54 13.04 US$, United States dollars. a In period 1 (41 days) cylinders were the principal source of oxygen, although concentrators were occasionally used. b In period 2 (45 days) concentrators were the principal source of oxygen, although cylinders were occasionally used. c Formula: Running cost = unit cost × (hours used/40 000). Projected lifespan of 40 000 hours running time (approximately 5 years). Unit cost: US$ 1763. d Formula: [Power cost per kilowatt-hour (kWh) from generator × power rating of concentrator × hours spent running concentrator from generator] + [power cost per kWh from grid × power rating of concentrator × hours spent running concentrator from grid]. Power cost from generator: US$ 0.19/ kWh; power cost from grid: US$ 0.28/kWh; power rating of concentrators: 0.4 kW; hours of generator versus grid power: Period 1, generator 169 hours, grid 156 hours; Period 2, generator 980 hours, grid 905 hours. e Formula: Piping cost = Piping original cost × (duration study/lifespan of piping). Projected lifespan of piping 20 years. Original cost of piping including installation: US$ 16 633. f Formula: Cylinder running cost = cylinder unit supply cost × (litres used/6000). Cost of one 6000-L cylinder: US$ 30.18. g The average oxygen consumption per patient in each period among the 38 patients in the study was 15 529 L. This average consumption was multiplied by the cost per litre to obtain the adjusted cost per average patient. at a cost of US$ 1800 per life saved, or US$ 54 per disability-adjusted life-year (DALY) averted. This is less than the cost of other interventions intended to prevent deaths from pneumonia, such as administering the conjugate pneumococcal vaccine (US$ 100 per DALY averted).35,36 The annual cost of saving these lives was estimated to be approximately US$ 76 000 for all health facilities combined, only 50% more than the amount spent on oxygen at the Royal Victoria Teaching Hospital alone in 2004.6 Having a reliable oxygen supply is an important goal for health facilities where cases of severe pneumonia are managed. Neither concentrators nor cylinders are well suited to every situ- ation, and a simple options assessment can determine which is the preferable primary supply source in each setting. Options assessment is likely to lead to improvements in oxygen supply and reductions in costs compared with the costs associated with conventional cyl- inders. To facilitate this exercise we have produced a computer-based tool based on the present study (available from corresponding author). The challenge of then sustaining the supply should not be underestimated, and much work remains to be done to fully meet this challenge. Nevertheless, it is precisely this type of health service development that will be needed to achieve sustained reductions in child mortality worldwide. ■ Competing interests: None declared. Résumé Répondre aux besoins en oxygène en Afrique : analyse des options pour la Gambie Objectif Comparer les options d’approvisionnement en oxygène qui s’offrent aux établissements de soins de Gambie et développer un algorithme de prise de décisions pour guider le choix des systèmes d’approvisionnement en oxygène en Afrique et dans le reste du monde en développement. Méthodes Les auteurs ont comparé en termes de fonctionnalité et de coût les bouteilles et les concentrateurs d’oxygène. Ils ont interrogé des informateurs clés en utilisant des instruments d’évaluation OMS mis au point et adaptés localement et réalisé des évaluations opérationnelles, ainsi qu’une modélisation et des mesures des coûts pour déterminer le meilleur choix entre les bouteilles et les concentrateurs d’oxygène. Ils ont élaboré un algorithme et un outil logiciel pour guider la sélection du système d’approvisionnement en oxygène. Résultats En Gambie, les concentrateurs d’oxygène présentent des avantages notables par rapport aux bouteilles lorsque l’alimentation électrique est fiable ; dans d’autres contextes, il est préférable de faire appel aux bouteilles dans la mesure où leur transport est praticable. La présence de fuites, phénomène courant, influe fortement sur le coût des bouteilles, tandis que pour les concentrateurs, les coûts énergétiques sont de loin plus importants que les coûts en capital. Sur les 12 établissements gambiens, 2 seulement avaient intérêt d’après l’étude à utiliser des concentrateurs ; pour les 10 autres, les bouteilles constituaient une meilleure option. Conclusion Ni les concentrateurs, ni les bouteilles ne conviennent à toutes les situations, mais une évaluation simple des options permet de déterminer pour chaque contexte la meilleure solution. A l’échelle nationale, cette évaluation devrait conduire à une amélioration de l’approvisionnement et à une baisse des coûts par rapport à la situation où l’on utilise uniquement des bouteilles d’oxygène classiques, mais assurer un approvisionnement fiable devrait rester un défi. L’algorithme décisionnel et l’outil logiciel conçus pour la Gambie devraient être applicables dans d’autres pays en développement. 770 Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Research Meeting oxygen needs in Africa Stephen RC Howie et al. Resumen Atender las necesidades de oxígeno en África: análisis de opciones en Gambia Objetivo Comparar las opciones de suministro de oxígeno para centros de salud en Gambia y desarrollar un algoritmo decisional para elegir los sistemas de suministro de oxígeno en África y en el resto del mundo en desarrollo. Métodos Se compararon la funcionalidad y el costo de las bombonas y los concentradores de oxígeno. Se llevaron a cabo entrevistas con informantes clave mediante instrumentos desarrollados localmente o adaptados a partir de otros de la OMS, evaluaciones operacionales, modelizaciones de costos y mediciones de costos a fin de determinar la mejor opción entre las bombonas y los concentradores de oxígeno. Se desarrolló así un algoritmo y un instrumento de software para fundamentar la elección del sistema de suministro de oxígeno. Resultados En Gambia, los concentradores de oxígeno presentan ventajas importantes en comparación con las bombonas allí donde el suministro eléctrico es fiable; en caso contrario, la opción preferible son las bombonas, siempre y cuando sea factible transportarlas. El costo de las bombonas depende considerablemente de las fugas, un problema frecuente, mientras que el de los concentradores depende mucho más del costo de la electricidad que de los gastos de infraestructura. Sólo dos de los 12 centros de Gambia analizados reunían las condiciones idóneas para usar concentradores; en los otros diez centros, la mejor opción eran las bombonas. Conclusión Ni los concentradores ni las bombonas son soluciones ideales para cualquier situación, pero una simple evaluación de esas dos opciones permite determinar cuál es preferible en cada entorno. A nivel nacional, esa diferenciación se traduciría en mejoras del suministro y menores costos en comparación con el uso exclusivo de las bombonas convencionales, pero seguiría habiendo problemas para garantizar un suministro fiable. El algoritmo decisional y el instrumento de software concebidos para Gambia podrían aplicarse en otros países en desarrollo. References 1. Revised global burden of disease (GBD) 2002 estimates. Geneva: World Health Organization; 2005. Available from: http://www.who.int/healthinfo/ global_burden_disease/estimates_regional_2002_revised/en/ [accessed on 21 July 2009]. 2. Black RE, Morris SS, Bryce J. Child survival series: where and why are 10 million children dying every year? Lancet 2003;361:2226-34. PMID:12842379 doi:10.1016/S0140-6736(03)13779-8 3. Jaffar S, Leach A, Greenwood A. Changes in the pattern of infant and childhood mortality in Upper River Division, The Gambia, from 1989 to 1993. Trop Med Int Health 1997;2:28-37. PMID:9018300 doi:10.1046/j.1365-3156.1997. d01-131.x 4. Management of the child with serious infection or severe malnutrition. Geneva: World Health Organization; 2000 (WHO/FCH/CAH/00.1). 5. Report of WHO informal consultation on clinical use of oxygen. Geneva: World Health Organization; 2003. Available from: http://www.who.int/surgery/ collaborations/Oxygen_Meeting_Report_Geneva_2003.pdf [accessed on 21 July 2009]. 6. Hill SE, Njie O, Sanneh M, Jallow M, Peel D, Njie M, et al. Oxygen for treatment of severe pneumonia in The Gambia, West Africa: a situational analysis. Int J Tuberc Lung Dis 2009;13:587-93. PMID:19383191 7. Dobson MB. Oxygen concentrators and cylinders. Int J Tuberc Lung Dis 2001;5:520-3. PMID:11409577 8. Howie SR, Hill SE, Peel D, Sanneh M, Njie M, Hill PC, et al. Beyond good intentions: lessons on equipment donation from an African hospital. Bull World Health Organ 2008;86:52-6. PMID:18235890 doi:10.2471/ BLT.07.042994 9. Wright J. Health needs assessment in practice. London: BMJ Books; 1998. 10. Stevens A, Raftery J. Health care needs assessment. London: Radcliffe Medical Press; 1997. 11. Coster G. Health needs assessment for New Zealand [background paper and literature review]. Wellington: Ministry of Health; 2000. 12. McPake B, Kumaranayake L, Normand C. Health economics: an international perspective. London: Routledge; 2002. 13. Consensus Conference on Guidelines on Economic Modelling in Health Technology Assessment. Decision analytic modelling in the economic evaluation of health technologies. A consensus statement. Pharmacoeconomics 2000;17:443-4. PMID:10977386 14. Central Bank of The Gambia. Official exchange rates for valuation purposes. Available from: http://www.cbg.gm/archives/previous-rates.html [accessed on 4 February 2008]. صخلم ايبماغ نم تارايتخلال ليلحت :ايقيرفأ في ينجسكلأا تاجايتحا ةيبلت دادعإو ايبماغ في ينجسكلأاب ةيحصلا قفارلما دادمإ تارايتخا ةنراقم :فدهلا ةيقبو ايقيرفأ في ينجسكلأا ليصوت مُظُن رايتخا لوح رارقلا ذاختلا ةيمزراوخ .ةيمانلا نادلبلا ثيح نم ينجسكلأا تافثكمو )تاناوطسا( يرساوم نوثحابلا نراق :ةقيرطلا مادختساب ينيسيئرلا نيبرخلما عم تلاباقم اورجأف ،اهفيلاكتو اهفئاظول اهئادأ عم ،ليحلما عقولما مئلاتل اهفييكت عم ةيلماعلا ةحصلا ةمظنم اهتدعأ ةرماتسا فرعتلل فيلاكتلل تاسايقو فيلاكتلل جذانم دادعإو ةيناديم تماييقت ءارجإ رايتخا يه ينجسكلأا تافثكم تناك وأ )تاناوطسا( يرساوم تناك اذإ ام لىع ليصوت ماظن رايتخا هيجوتل تايجمربو ةيمزراوخ نوثحابلا ىنبو .لضفأ .ينجسكلأا يرساولماب ةنراقم ةماه عفانبم ينجسكلأا تافثكم عتمتت ايبماغ في :تادوجولما امأ ،ةقاطلا رفاوت لىع اهيف دماتعلاا نكيم يتلا عقاولما في كلذو ،)تاناوطسلاا( .ًانكمم اهلقن نوكي مانيح )تاناوطسلاا( يرساولما لضفتف ،ىرخلأا عقاولما في عئاش رمأ وهو ،بسرتلاب يربك ٍدح لىإ )تاناوطسلاا( يرساولما ةفلكت رثأتتو فيلاكتب رثأتت مام ثركأ ةقاطلا فيلاكتب تافثكلما ةفلكت رثأتت مايف ،ثودحلا ايبماغ في ًاقفرم 12 لصأ نم يننثا قفرم نأ نوثحابلا دجو دقو .لالما سأر )تايناوطسلاا( يرساولما نإف ةيقبتلما ةشرعلا قفارلما امأ .تافثكملل نائملام . لضفأ رايتخا يه ،عاضولأا عيمج )تايناوطسلاا( يرساولما لاو تافثكلما بسانت لا :جاتنتسلاا .عقوم لك في لضفأ ماهيأ ددحي نأ نكيم تارايتخلال ًاطيسب ًماييقت نكلو فيلاكتلا ضيفختو دادملإا ينسحت لىإ كلذ يدؤيس ،ينطولا ديعصلا لىعو مغر كلذو ،اهدحول )تاناوطسلاا( يرساوملل داتعلما مادختسلاا عم ةنراقلماب ةادلأاو رارقلا ذاختا ةيمزراوخ نإ .ًايدحت ىقبيس قوثولما دادملإا نماض نأ .ىرخأ ةيمان نادلب في اهقيبطت نكيم ايبماغل ةممصلما ةيجمبرلا 771Bull World Health Organ 2009;87:763–771 | doi:10.2471/BLT.08.058370 Research Meeting oxygen needs in AfricaStephen RC Howie et al. 15. xe.com. Current and historical rate tables. Available from: http://www.xe.com/ ict/ [accessed on 15 February 2008]. 16. Junge S, Palmer A, Greenwood BM, Kim Mulholland E, Weber MW. The spectrum of hypoxaemia in children admitted to hospital in The Gambia, West Africa. Trop Med Int Health 2006;11:367-72. PMID:16553917 doi:10.1111/ j.1365-3156.2006.01570.x 17. American Hospital Association. Estimated useful lives of depreciable hospital assets. Chicago, IL: American Hospital Publishing; 1998. 18. Emergency Care Research Institute. Oxygen concentrators. Plymouth Meeting, PA: ECRI, 2004. 19. Oxygen therapy for acute respiratory infections in young children in developing countries. Geneva: World Health Organization; 1993 (ARI/93.28). Available from: http://www.who.int/child-adolescent-health/New_ Publications/CH.../WHO_ARI_93.28.html [accessed on 29 July 2009]. 20. Schneider G. Oxygen supply in rural Africa: a personal experience. Int J Tuberc Lung Dis 2001;5:524-6. PMID:11409578 21. Shrestha BM, Singh BB, Gautam MP, Chand MB. The oxygen concentrator is a suitable alternative to oxygen cylinders in Nepal. Can J Anaesth 2002;49:8-12. PMID:11782322 doi:10.1007/BF03020412 22. Mokuolu OA, Ajayi OA. Use of an oxygen concentrator in a Nigerian neonatal unit: economic implications and reliability. Ann Trop Paediatr 2002;22:209-12. PMID:12369483 doi:10.1179/027249302125001499 23. Dobson M, Peel D, Khallaf N. Field trial of oxygen concentrators in upper Egypt. Lancet 1996;347:1597-9. PMID:8667871 doi:10.1016/S0140- 6736(96)91080-6 24. Perrelet A, Zellweger JP, Talla I, Ndiaye Y, Gautier E, Gehri M. The oxygen concentrator: an appropriate technology for treating hypoxaemic children in developing countries. Int J Tuberc Lung Dis 2004;8:1138-41. PMID:15455602 25. Dobson MB. Oxygen concentrators offer cost savings for developing countries. Anaesthesia 1991;46:217-9. PMID:2014901 doi:10.1111/j.1365-2044.1991.tb09413.x 26. Dobson MB. Oxygen concentrators for the smaller hospital — a review. Trop Doct 1992;22:56-8. PMID:1604716 27. Litch JA, Bishop RA. Oxygen concentrators for the delivery of supplemental oxygen in remote high-altitude areas. Wilderness Environ Med 2000; 11:189-91. PMID:11055565 28. Wood PB. Oxygen concentrator in a remote hospital in Zaire. Trop Doct 1985;15:26-7. PMID:3976002 29. Pedersen J, Nyrop M. Anaesthetic equipment for a developing country. Br J Anaesth 1991;66:264-70. PMID:1817634 doi:10.1093/bja/66.2.264 30. Enarson P, La Vincente S, Gie R, Maganga E, Chokani C. Implementation of an oxygen concentrator system in district hospital paediatric wards throughout Malawi. Bull World Health Organ 2008;86:344-8. PMID:18545736 doi:10.2471/BLT.07.048017 31. Oduro KA. Trends in the supply of oxygen in hospital — oxygen concentrators — Korle Bu experience. West Afr J Med 1992;11:244-6. PMID:1304786 32. Singh V, Kothari K, Khandelwal R. Adequacy assessment of oxygen therapy. J Assoc Physicians India 2000;48:701-3. PMID:11273504 33. Weber MW, Mulholland EK. Pulse oximetry in developing countries. Lancet 1998;351:1589. PMID:10326572 doi:10.1016/S0140-6736(05)61160-9 34. Duke T, Wandi F, Jonathon M, Matai S, Kaupa M, Saavu M, et al. Impact of improved oxygen systems on child deaths from pneumonia: a multi-hospital effectiveness study in Papua New Guinea. Lancet 2008;372:1328-33. PMID:18708248 doi:10.1016/S0140-6736(08)61164-2 35. Disability adjusted life years (DALY). Geneva: World Health Organization. Available from: http://www.who.int/healthinfo/boddaly/en/ [accessed on 17 May 2008]. 36. Sinha A, Levine O, Knoll M, Muhib F, Lieu T. Cost-effectiveness of pneumococcal conjugate vaccination in the prevention of child mortality: an international economic analysis. Lancet 2007;369:389-96. PMID:17276779 doi:10.1016/S0140-6736(07)60195-0