Pulse oximetry in devloping Countries

Abstract

SIR—Hypoxaemia is the most severe manifestation of pneumonia. Lack of oxygen does not just stop the machine, it wrecks it. The efforts of the World Health Organisation and other agencies have therefore concentrated on supplying oxygen reliably to small hospitals in developing countries. Unfortunately, hypoxaemia is difficult to detect on clinical signs alone because these lack sensitivity. The pulse oximeter, which is selfcalibrating, was therefore a step forward. The cost is considerable ($1500) but oxygen cylinders cost $40 each in The Gambia so the purchase of a pulse oximeter would be soon repaid if oxygen could be targeted at really hypoxaemic children and the flow rate adjusted to the lowest rate which prevents hypoxaemia. We have used pulse oximeters (Nellcor N 200, donated by the manufacturer) routinely in three hospitals in The Gambia for studies and for routine clinical use between 1990 and 1997. The oximeters were used by trained fieldworkers during part of the working day. Since the fieldworker’s main task was assessing children with the use of the oximeter, they handled the machines quite well. Outside routine working hours and at weekends, the machines were used by nurses, who generally handled the machines more roughly, though such handling probably more accurately reflects actual use in a developing country. Between 5000 and 10 000 individual measurements were done per year with each machine. In 1993 and 1994, two machines were used for permanent measurements on children with hypoxaemia enrolled in a study on oxygen delivery. The figure shows the lifetime history of the five oximeters. On average, a repair was needed every 2–3 years. There are no licensed repair shops in west Africa so every repair, which was indicated by malfunction of the oximeter, required shipment to the Netherlands, at an average cost of $500 for repair and shipment. Cable breaks became more frequent as the oximeters aged, and cable replacement costs $250. Finger clip-on sensors, which were used even on small babies covering the whole hand or foot, lasted about 6 months on average and replacements cost $250. Pulse oximeters improve the care of children with pneumonia or who are critically ill, and have the potential for cost saving on oxygen, especially if oxygen has to be provided in cylinders. The initial investment is considerable and is followed by half this investment on an annual basis for maintenance. To improve their affordability in developing countries, efforts should be made by manufacturers to improve the longevity of parts and to expand the service network in developing countries.