or the patient being exposed to the unhealthy atmosphere. This is carried out by a coupling on the face of each mask. When they are joined, an airway is formed, allowing ventilation to proceed.
Sometimes during artificial ventilation, air is forced into the stomach instead of into the lungs. The stomach becomes distended (bulges), indicating that the airway is blocked or partially blocked, or that ventilations are too forceful. This problem is more commonly seen in children but can occur with any patient. A slight bulge is of little worry, but a major distention can cause two serious problems. First is a reduced lung volume; the distended stomach forces the diaphragm up. Second, there is a strong possibility of vomiting.
The best way to avoid gastric distention is to properly position the head and neck and/or limit the volume of ventilations delivered.
NOTE: THE AMERICAN HEART ASSOCIATION (AHA) STATES THAT NO ATTEMPT SHOULD BE MADE TO FORCE AIR FROM THE STOMACH UNLESS SUCTION EQUIPMENT IS ON HAND FOR IMMEDIATE USE.
If suction equipment is ready and the patient has a marked distention, you can turn the patient on his or her side facing away from you. With the flat of your hand, apply gentle pressure between the navel and the rib cage. Be prepared to use suction should vomiting occur.
AS a corpsman, you should become familiar with various pieces of supportive equipment that may be available to help you to maintain an open airway and to restore breathing in emergency situation. They include artificial airways, the bagvalve-mask system, the mouth-to-mask system with the oxygen-inlet valve, and suction.
In an emergency first aid situation, the corpsman will probably have a size E, 650-liter cylinder available. This is fitted with a yoke-style pressure reducing rcgtilator, with gauges to show tank pressure and flow rate (adjustable from 0 to 15 liters per minute). A humidifier can be attached to the flowmeter nipple to help prevent tissue drying caused by the water vapor free oxygen. An oxygen line can be connected from the flowmeter nipple or humidifier to a number of oxygen delivery devices that will be discussed later.
When available, oxygen should be administered, as described below, to cardiac arrest patients and to self-ventilating patients who are unable to inhale enough oxygen to prevent hypoxia (oxygen deficiency). Hypoxia is characterized by tachycardia, nervousness, irritability, and finally cyanosis. It develops in a wide range of situations from poisoning to shock, crushing chest injuries, cerebrospinal accidents, and heart attack.
Oxygen must never by used near open flames since it supports burning. The cylinders must be handled carefully since they are potentially lethal missiles if punctured or broken.
The oropharyngeal and nasopharyngeal airways are primarily used to keep the tongue from occluding the airway.
OROPHARYNGEAL AIRWAY. This airway can be used only on unconscious victims because a conscious person will gag on it. They come in various sizes for different age groups (it is important to choose the correct size for the victim), and they are shaped to rest on the contour of the tongue and extend from the lips to the pharynx.
One method of insertion is to depress the tongue with a tongue blade and slide the airway in. Another method is to insert the airway upside down into the victims mouth; then rotate it 180 degrees as it slides into the pharynx (fig. 4-12).
NASOPHARYNGEAL AIRWAY. This airway may be used on conscious victims since it is better tolerated because it generally does not stimulate the gag reflex. Since they are made of flexible material, they are designed to be lubricated and then gently passed up the nostril and down into the pharynx. If the airway meets an obstruction in one nostril, withdraw it and try to pass it up the other nostril.
The bag-valve-mask system (fig. 4-13) is designed to help ventilate an unconscious victim for long periods, while delivering high concentrations of oxygen. This system can be useful in extended CPR attempts because when using external