Basic respiratory physiology: one of the functions of the nose is to increase the humidity of the inhaled air to close to 100%. Breathing through the mouth defe

Basic respiratory physiology: one of the functions of the nose is to increase the humidity of the inhaled air to close to 100%. Breathing through the mouth defeats this apparatus. Whenever a patient has their upper airway bypassed due to a medical procedure (such as intubation), we use a heat and moisture exchanger (HME) or a humidifier. I run with a surgical mask during cold weather because it acts as a poor man’s HME.