injuries and poisoning
Barotrauma
Prevention of Barotrauma
Pressure in the lungs and airways is automatically equalized with outside pressure when a supply of pressurized air is available at depth, as from a diving helmet or air tank. This pressurized air also equalizes pressure in the sinuses, as long as the openings to the sinuses are not narrowed, for example, by inflammation due to allergies or an upper respiratory tract infection. Pressure in a face mask is equalized by blowing out air from the nose into the mask. Divers equalize pressure differences in the middle ear by yawning or swallowing with the nostrils pinched, which opens the tube connecting the middle ear and the back of the throat (eustachian tube). Wearing earplugs or a tight-fitting wet suit hood creates a closed space between the earplug and the eardrum in which pressure cannot be equalized. The pressure inside eye goggles cannot be equalized either. Therefore, neither earplugs nor eye goggles should be worn during diving. Tight-fitting wet suit hoods should be properly vented so that they do not block the external ear. A decongestant (such aspseudoephedrinetaken by mouth or a nasal spray such asoxymetazoline) is taken before diving by people with nasal congestion that could block nasal passages. Relief of congestion can facilitate equalization of pressures between the ears and sinuses, helping prevent sinus and ear barotrauma. To prevent pulmonary barotrauma, people must freely exhale any air inhaled at depth—even the depth of a swimming pool—during ascent. People with lung disease such as asthma should be assessed before engaging in diving for fitness to dive. 