An audit of electronic oxygen prescribing and bedside observations at a UK teaching hospital showing a high prevalence of risk factors for hypercapnia and a high incidence of hyperoxaemia

Abstract

Introduction: Hypoxaemia is dangerous and is treated with supplemental O 2 but excessive O 2 therapy causes hypercapnia in many common diseases. O 2 saturation (SpO 2 ) forms an integral part of vital sign monitoring using Early Warning Score (EWS) systems. We have audited O 2 prescribing and SpO 2 measurements at a large teaching hospital. Methods: Electronic prescription and observation records were studied for every patient on our medical and surgical wards in December 2014. Observations taken in theatre and critical care areas were excluded. Results: 6800 patients (81,753 observation sets) were studied. A target O 2 saturation range was prescribed for 99.8% of audited patients. 95.2% of SpO 2 observations on air were satisfactory compared with 60.5% of observations on oxygen therapy (32.1% of 13956 observations on O 2 were above the prescribed target range and 7.4% were below range). 11.8% of patients (17.3% of medical and 9.0% of surgical patients) had a prescribed target range of 88-92% (at risk of hypercapnia). Observations for these patients were more likely to be made whilst using supplementary O 2 (33.4 v 15.2% for low-risk patients). Amongst patients with target range 88-92% who were using oxygen therapy, 70.1% of 877 observations on surgical wards and 47.5% of 2778 observations on medical wards had excessively high SpO 2 (≥93%) . Conclusion: Electronic prescribing can deliver a target saturation range for >99% of hospital patients. Almost 12% of patients at our hospital were deemed to be at risk of hypercapnia but, despite this, hyperoxaemia was four times more common than hypoxaemia.