Asymmetrical Versus Conventional High-flow Nasal Cannula in Acute Respiratory Failure

The goal of this randomized crossover physiological study is to evaluate the physiologic effects of asymmetrical nasal cannula and conventional nasal cannula in patients with acute respiratory failure. The main questions it aims to answer are: * Does the asymmetrical high-flow nasal cannula reduce the diaphragm and parasternal intercostal work activity of breathing measured by ultrasound compared to conventional high-flow nasal cannula? * What is the effect of the asymmetrical high-flow nasal cannula on breathing pattern, gas exchange, and hemodynamic variables compared to conventional high-flow nasal cannula? Participants will received asymmetrical high-flow nasal cannula or conventional high-flow nasal cannula at a flow rate of 40 and 60 L/min in a random order.