HFNC vs Two Nare HFNC in Extubated Patients

High flow nasal cannula (HFNC) are introduced to clinical practice to improve oxygenation. Our group were the first to report the use of HFNC in extubated patients that showed comparable delivery of oxygen and improved comfort. These HFNC are subsequently shown to be useful in several clinical conditions in critically ill patients including respiratory failure due to hypoxia, hypercapnia (exacerbation of chronic obstructive lung disease), or post-extubation, pre-intubation oxygenation, and others. Recently a new mode of high flow oxygen therapy has been presented on the market where the prongs of high flow have two different diameters. These two-nare size high flow nasal cannula are capable of delivering gases at a flow rate of 15-50 L/min, similar to the conventional HFNP but the difference in the diameters provide different levels of positive pressure as compared to conventional HFNP. This positive pressure could help in gas exchange of patients who need more oxygen. These devices are approved by the Therapeutic Goods Administration (TGA); the medicine and therapeutic regulatory agency of the Australian Government. Our aim is to compare the two size nare high flow nasal cannula with conventional high flow nasal cannula in extubated patients in intensive care unit in a randomised crossover trial. The comparison will include arterial blood gasses, physiological data including heart rate, respiratory rate, saturations as well as comfort and tolerance of the patients to two size nare high flow nasal cannuale.