Oxygen therapy in respiratory disorders
Oxygen therapy remains a cornerstone of medical practice and is generally regarded as being safe. However, there is a lack of clinical evidence to support the routine use of oxygen therapy, and in certain conditions, injudicious oxygen may cause harm. In this thesis, I will present two audits and three randomised controlled trials of oxygen therapy. Methods A prospective audit of the prescription and use of oxygen therapy before and after the introduction of an oxygen prescription section on a drug chart A retrospective audit of ambulance oxygen administration, in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) Two randomised controlled trials of high flow versus titrated oxygen in 150 patients with community acquired pneumonia and 106 patients with acute severe asthma A randomised controlled trial of 24 subjects with obesity hypoventilation syndrome (OHS) comparing 100% oxygen with air Results Oxygen prescription is suboptimal in hospital inpatients. Whilst an oxygen prescription section improved prescription, this intervention did not improve clinical practice Over 70% of patients presenting with AECOPD received high flow oxygen prior to presentation to the emergency department. The risk of adverse outcomes increased progressively with increased PaO2 High concentration oxygen leads to a rise in PaCO2 compared to titrated oxygen, when administered to patients presenting with asthma or pneumonia Breathing 100% oxygen leads to a rise in PaCO2 in patients with OHS Conclusion This series of studies has shown that further measures are warranted to ensure the safe practice of oxygen therapy in the pre-hospital and hospital setting. In addition, the findings suggest that the potential for high concentration oxygen therapy to increase PaCO2 is not limited to COPD but may occur in other respiratory conditions in which abnormal gas exchange or respiratory drive are present.
- Theses