**6. High flow nasal cannula**

Keeping in mind the human factors of comfort, humidification and warming of inspired air are essential in creating an effective oxygenation system (**Figure 5**). Basic components of high flow nasal cannula (HFNC) include a flow generator providing gas flow rates up to 60 liters per minute, an air-oxygen blender that achieves escalation of FIO2 from 21–100% irrespective of flow rates, and a humidifier that saturates the gas mixture at a temperature of 31 to 37 C [15]. To minimize condensation, the heated humidified gas is delivered via heated tubings through a wide-bore nasal prong. In this system all settings are controlled independently, so maximum delivery of oxygen thence better outcome.

Mechanism responsible for high efficacy includes Physiological dead space (which accounts for approximately one-third of the tidal volume of breathing) washout of waste gasses including carbon dioxide (CO2), Decreased respiratory rate, Positive end-expiratory pressure, Increased tidal volume and Increased endexpiratory volume.

**Figure 5.** *Showing high flow nasal cannula used for hypoxic respiratory failure.*
