VentilationVentilation is the mechanical process by which air enters and leaves the lungs. Situations in which a patient may need ventilatory support range from apnea to patients with depressed respiratory function. If the patient's respiratory rate decreases significantly, this can lead to hypercapnia, hypoxia, decreased pH, and decreased minute respiratory volume. This can lead to cardiac or respiratory arrest if not corrected. Exhaled air ventilation has been accepted as the technique of choice since the late 1950s. This practice has been shown to be effective for both professionals and lay people, including young children over 5 years of age. Ventilation using the rescuer's exhaled air can be applied to the adult victim's mouth or nose as well as the infant's mouth and nose. Mouth-to-mouth ventilation and mouth-to-nose ventilation can provide effective ventilatory support to a patient. A major advantage of these ventilation methods is that no equipment is required to effectively provide ventilatory support to the patient. However, the disadvantage of these methods of ventilatory support is that both methods offer only a limited supply of oxygen due to the fact that the oxygen exhaled by the rescuer contains only 17 percent oxygen. Mouth-to-mask ventilation or pocket mask ventilation A clear plastic, molded face mask similar to that used in anesthesia can be used to provide mouth-to-mask ventilation. A one-way valve diverts the patient's exhaled air away from the rescuer and traps any macroscopic particles emerging from the patient. This valve improves aesthetics and reduces the risk of cross infection. The mouth-to-mask method consists of two hours of paper...applied intermittently, amounting to controlled mechanical ventilation in patients who are not breathing. Some contain a “pop-off” valve that prevents pressure-related injuries. A "pop-off" valve can be harmful in situations where the patient suffers from pulmonary contusion, bronchospasm, cardiogenic pulmonary edema, adult respiratory distress syndrome or disorders in which high levels of pressure in the airways must be overcome. In conclusion, there are several effective methods for providing respiratory support to patients. Although the mechanical ventilator has many advantages, as mentioned previously, the bag valve method is found to have the greatest number of advantages. However, it should be noted that the bag valve technique has also proven problematic when attempting to offer respiratory support to non-intubated patients...