permits a tight seal over both the mouth and nose. They should not have a pop-off valve as sometimes high pressures are needed. The main goal of ventilation is to maintain oxygenation. This is evidenced as having a pulse oximeter saturation of O2 of 90 percent or greater. If it isn’t working, check the seal, use of jaw thrust, insertion of oral airway or nasal airway, and mask size. Suction the airway if needed. Squeeze the 1-liter bag about two-thirds of the way for a minimum of 600 cc (up to 800 cc) per squeeze. From a physiological perspective, the BVM ventilation is positive pressure ventilation versus the negative pressure ventilation used by people normally. It forces air into the lungs instead of having air drawn into them. The main side effect is decreased cardiac output from reduced venous return to the right side of the heart—made worse in hypovolemia. This is why ventilation should be minimized in CPR. Another downside to BVM ventilation is barotrauma—most commonly the pneumothorax. This comes from delivering higher than normal tidal volumes during BVM ventilation. Gastric distention and gastric perforation can also occur.
TRACHEAL INTUBATION In some cases, tracheal intubation cannot be done. Some patients respond to a double lumen device instead, which can be blindly inserted with less skill than required for a tracheal intubation. It involves the placement of a flexible tube into the trachea in order to have a protected airway. It mainly allows for ventilation but also is a conduit for the administration of certain drugs. In the conscious or semi-conscious patient, it requires general anesthesia and a neuromuscular blocking drug or a strong local anesthetic. It requires a laryngoscope, flexible fiberoptic bronchoscope, or a video laryngoscope in order to place the device safely. These allow for visualization of the vocal cords, through which the ET tube passes.
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