Nasal high flow therapy in acute respiratory failure in Chronic Obstructive Pulmonary Disease – A feasibility study.

A standard of care protocol for Acute Exacerbation of COPD patients with Acute Hypercapnic Respiratory failure (AHRF) with acidosis will be agreed upon with Emergency Department staff. Patients presenting with an Acute Exacerbation of COPD will have an Arterial blood gas (ABG) as per current guidelines and venous blood gas (VBG) as per standard hospital practice. Patients with a PaCO2 greater than 45mmHg and pH of greater than or equal to 7.25 and less than 7.35 will be enrolled into the observational study using a deferred consent model. A deferred consent model is required as people with COPD and acute hypercapnic respiratory failure have impaired capacity. All participants will receive standard medical therapy, including oxygen therapy titrated to oxygen saturations of 88-92%, bronchodilators and steroids as appropriate. After the 60 minute optimisation period participants will have a paired ABG and VBG and need for non-invasive ventilation will be assessed. Subsequent care will be determined by the treating physician. During the 60 minute observational period the treatments received will be recorded to allow comparison of treatment received with the agreed standard care protocol. All participants will have their oxygen saturations and heart rate recorded by a pulse oximeter. This data will be downloaded after the 60 minute period completes. As an observational study there is no intervention and all participants will receive standard medical care throughout. Participants will undergo one additional venous blood test that they would not normally require. Deferred consent for the use of data will be obtained from patients once they are well enough to give informed consent. This will usually be within 48 hours of admission. If participants do not give consent their data will not be used in the study analysis.