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 costsf | 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.