SCREENING PATIENTS IN GENERAL-PRACTICE WITH COPD FOR LONG-TERM DOMICILIARY OXYGEN REQUIREMENT USING PULSE OXIMETRY

Epidemiological data suggest long term oxygen therapy (LTOT) delivered by oxygen concentrators in patients with severe hypoxic chronic obstr uctive pulmonary disease (COPD) is under-prescribed by General Practit ioners (GPs) in England and Wales. One reason for this may be the unav ailability to GPs of a measure of arterial oxygenation needed to fulfi l the defined prescription criteria. Provision of a non-invasive measu re of oxygenation may improve detection of hypoxic subjects and increa se appropriate prescribing. This study aimed to evaluate pulse oximetr y in a general practice setting and to screen for severe undetected hy poxaemia fulfilling the LTOT prescription criteria in patients with CO PD. All COPD patients attending surgery in two practices were screened with oximeters for hypoxaemia. Those with an oxygen saturation of les s than or equal to 92% were referred to hospital for formal arterial b lood gas analysis and an oxygen concentrator assessment. GPs were aske d to evaluate their experience in the ease of use and application of o ximetry. The number of patients receiving oxygen by concentrator befor e the study was compared with the national rate and the number after t he study with the estimated need suggested by epidemiological studies. Over a 12-month period a total of 114 patients were screened in the t wo practices with a combined list size of 15 742. Thirteen patients ha d saturations of less than or equal to 92%. Two refused and 11 underwe nt formal arterial gas analysis. Three had PaO2 <7.3 kPa and new presc riptions for oxygen concentrators were made in these previously unsusp ected severely hypoxaemic subjects as a result. One other hypoxaemic s ubject was referred and found to have another treatable medical condit ion. The initial prevalence of concentrator prescription (0.013% CI 0. 003, 0.047) was similar to the national rate (0.024%) and the prevalen ce observed after screening (0.031%, CI 0.013, 0.073) fell within the lower suggested prescription need of previous epidemiological data (0. 02-0.10%). All practitioners found the oximeters simple to use and hel pful in assisting with assessment of the severity of their patients' c ondition. Oximetry provides a readily usable non-invasive method of sc reening and when applied to all COPD patients seen in general practice can reveal those fulfilling the criteria for long term oxygen who wou ld otherwise not be identified as needing this treatment.