Using titrated oxygen instead of high flow oxygen during an acute exacerbation of chronic obstructive pulmonary...

In patients with a suspected acute exacerbation of COPD, does titrated oxygen in the pre-hospital setting change mortality, length of hospital stay and blood gas measurements?

Cluster randomised controlled trial in which paramedics were allocated to deliver titrated or high flow oxygen. Randomisation sequence was concealed prior to allocation.

Ambulance service and emergency department in Hobart, Australia.

People who were: transported by ambulance to the emergency department, aged ≥35 years, breathless, and were thought to have COPD based on their acute symptoms, a patient-stated history of COPD, or a smoking history of > 10 pack-years. Randomisation of 64 paramedics allocated 32 to the titrated oxygen group and 30 to the high flow oxygen group. Over the study duration, 179 and 226 patients were allocated to the titrated and high flow oxygen groups, respectively.

Patients in both groups received basic support, nebulised bronchodilators, intravenous dexamethasone and, if necessary, intravenous or intramuscular salbutamol. In addition, the intervention group received titrated oxygen via nasal prongs, with the aim of maintaining arterial oxygen saturation, measured via a pulse oximeter (SpO(2)) between 88% and 92%. Nebulised therapy was delivered by compressed air. The control group received high flow oxygen (8 to 10 L/min) via a non-rebreather face mask. Nebulised therapy was delivered by compressed oxygen at 6 to 8 L/min.

The primary outcome was pre-and in-hospital mortality. Secondary outcomes were length of hospital stay and blood gas measurements.

The primary outcome was captured for all enrolled patients. According to the intention to treat (ITT) analysis, mortality in the intervention and control groups was 4% (n = 7) and 9% (n = 21), respectively. The relative risk was 0.42 (95% CI 0.20 to 0.89). Similar results were demonstrated when only those patients who had a physician-confirmed diagnosis of COPD were included in the analyses (mortality of 2%, n = 2, vs 9%, n = 11, and relative risk of 0.22, 95% CI 0.05 to 0.9]). The ITT analysis did not demonstrate between-group differences in the secondary outcomes.

In patients with a suspected acute exacerbation of COPD, using titrated oxygen to maintain SpO(2) between 88% and 92% reduced the risk of mortality by 58%. Physiotherapists working in acute care should strive to ensure that these patients are not treated with high-flow oxygen.