Assessing the use of initial oxygen therapy in chronic obstructive pulmonary disease patients: a retrospective audit of pre-hospital and hospital emergency management.

Background: Carbon dioxide retention in chronic obstructive pulmonary disease (COPD) exacerbations can be a complication of oxygen therapy. Current recommendations suggest an inspired oxygen level (FiO2 ) < 0.28, aiming for saturation (SpO2 ) of 88-92% until arterial blood gas analysis is available.

Aims: This study aims to assess the use of O2 therapy and FiO2 in the emergency management of patients with a known diagnosis of COPD.

Methods: Retrospective audit of 150 COPD patients admitted over 18 months, data being extracted from the hospital records.

Results: Of the records reviewed, 57% were male, mean age 75 years. COPD was recognised in 53%. SpO2 recorded in 124 patients, with SpO2 < 88% seen in 40 patients. Oxygen was administered in 123 patients in ambulances; high flow in 111 patients, and only 12 patients received O2 therapy in line with the recommended FiO2 < 0.28. In the emergency department (ED), 112 patients received O2 supplementation; high flow given in 68 patients. Hypercapnia was seen in 71 patients; FiO2 > 0.28 given in 54 patients in ambulances and in 35 patients in ED. Non-invasive ventilation was required in 53 patients; FiO2 > 0.28 given in 29 patients in the ED. Seven patients were admitted to intensive care unit, and 10 patients died.

Conclusion: High-flow oxygen is used for the initial treatment of COPD exacerbations, but only 53% are recognised as having COPD. A FiO2 > 0.28 is often initiated before admission and continued in the ED. A larger study would be required to assess any possible harm of this approach, but education of those involved in the care of COPD patients may reduce the risk of complications of hypercapnia.