MART Vol. II MO/MP - NESA - Civil Air Patrol

particularly on extended flights. Combating the loss of water during flightsrequires frequent water intake; experts recommend drinking 13-20 ounces (3-5mouthfuls) of fluid thirty minutes before you leave, and 4-6 ounces (a couple ofmouthfuls) every 15 minutes thereafter.Typical dehydration conditions are: dryness of the tissues and resultingirritation of the eyes, nose, and throat, and fatigue relating to the state of acidosis(reduced alkalinity of the blood and body tissues). A person reporting for a flightin a dehydrated state will more readily notice these symptoms until fluids areadequately replaced.Consumption of coffee, tea, cola, and cocoa should be minimized since thesedrinks contain caffeine. In addition, tea contains a related drug (theophyline),while cocoa (and chocolate) contain theobromine, of the same drug group. Thesedrugs, besides having a diuretic effect, have a marked stimulating effect and cancause an increase in pulse rate, elevation of blood pressure, stimulation ofdigestive fluid formation, and irritability of the gastrointestinal tract.Increasing the flow of outside air through the aircraft interior by the use ofvents, or opening windows or hatches can usually remedy heat-related problems.If sufficient airflow cannot be gained, cooler air can usually be located by climbingthe aircraft to a higher altitude. This may be inconsistent with search altitudesassigned by the incident commander or may be beyond the performancecapability of the aircraft.Altitude has several affects on human performance including ear block, sinusblock and hypoxia. Observers should be aware of these factors in their ownperformance and also watch for them to occur in other crewmembers.4.3.1 Ear blockAs the aircraft cabin pressure decreases during ascent, the expanding air inthe middle ear pushes the Eustachian tube open and, by escaping down it to thenasal passages, equalizes in pressure with the cabin pressure. But duringdescent, the pilot must periodically open the Eustachian tube to equalizepressure. This can be accomplished by swallowing, yawning, tensing muscles inthe throat or, if these do not work, by the combination of closing the mouth,pinching the nose closed and attempting to blow through the nostrils (valsalvamaneuver).Either an upper respiratory infection, such as a cold or sore throat, or a nasalallergic condition can produce enough congestion around the Eustachian tube tomake equalization difficult. Consequently, the difference in pressure between themiddle ear and aircraft cabin can build up to a level that will hold the Eustachiantube closed, making equalization difficult if not impossible. This problem iscommonly referred to as an "ear block."An ear block produces severe ear pain and loss of hearing that can last fromseveral hours to several days. Rupture of the eardrum can occur in flight or afterlanding. Fluid can accumulate in the middle ear and become infected. An earblock is prevented by not flying with an upper respiratory infection or nasal allergiccondition. Adequate protection is usually not provided by decongestant sprays ordrops to reduce congestion around the Eustachian tube. Oral decongestantshave side effects that can significantly impair pilot performance. If an ear blockdoes not clear shortly after landing, a physician should be consulted.64