In normal breathing, the anatomy of the upper airways helps to warm and humidify the inhaled air, retaining the heat and moisture present in the exhaled air. During inhalation, cold or dry air is usually heated to 37°C and when fully saturated, it contains 44 mg of H2O/L. In normal breathing, the anatomy of the upper airways helps to warm and humidify the inhaled gas, retaining the heat and moisture present in the exhaled air. Upon inhalation, the cold or dry gas is heated to body temperature and upon reaching the lungs, it contains the correct amount of moisture. In mechanical ventilation or anesthesia, the patient's upper airways may be bypassed by inserting an endotracheal tube. As a result, the patient's lungs may encounter cold and dry inhaled gas (Intersurgical.com). Prolonged exposure to dry ventilation gases can lead to: - Local inflammation in the trachea - Decrease in ciliary function - Retention and thickening of secretions - Decrease in patient temperature - Reduction in cardiac and pulmonary functions - Increased risk of endotracheal tube blockage - Increased duration and cost of care 104-300 with Luer lock port - Moisture loss 7.8 mg H2O/L - Calculated moisture return 30.8 mg H2O/L - Resistance at 30 L/min 0.5 cm H2O - Resistance at 60 L/min 1.6 cm H2O - Compressible volume 20 ml - Weight 11.8 g - Connectors 15M-22M/15F plus Luer port (104-300 only) - Minimum tidal volume >60 ml