ABC of healthy travel. During travel and acclimatisation.
Authors: E Walker, G Williams
Journal: BMJ (1983)

Motion sicknessSome problems, such as motion sickness, may occur during use of most forms of transport but others are specific to the pressurised cabins of Hyoscine passenger aircraft or to the speed of these aircraft in crossing time zones. CyclizineMany factors contribute to the onset of the nausea, dry mouth, and apathy that precede the vomiting of motion sickness.The effect of Promethazine unpredicted motion on the labyrinth is the main one aided by other sensory stimuli such as smells, reading, seeing others vomit, and alcohol intake.In those prone to motion sickness the anticholinergic drug hyoscine ~1 / /f t-~(Kwells) is a more effective prophylactic than the anti-cholinergic action of tj / / | antihistamines, although hyoscine is associated with more side effects, k A/\,j/\ \/ /particularly dry mouth, drowsiness, and blurred vision.Because of this it is best reserved for short trips, when a single prophylactic dose will suffice.It is contraindicated in those suffering from glaucoma.There is little difference in effect among the many preparations of antihistamines, although their side effects and duration of action vary.Cyclizine (Marzine) is a short-acting variety with less sedating effect and can readily be repeated.Promethazine (Avomine, Phenergan) is longer acting, has a low incidence of side effects, and is given as a single daily dose.Alcohol potentiates the sedating effect of all these drugs, and all impair driving ability.These preparations are no use once symptoms are established.Comfort during travelling is increased for all by choosing the most stable part of the vehicle-between the wings of an aeroplane, in the middle of a boat, or in the front seat of a car; by limiting food and alcohol intake; by adequate fresh air; and by lying down when practicable.Susceptibility to motion sickness tends to decrease with continued or repeated travel. Pressurised aircraft ContraindicationsModem passenger aircraft are not pressurised to the equivalent of Severe anaemia atmospheric pressure at sea level because fuselages would have to be much Severe otitis media and sinusitis stronger (and hence heavier and more costly) to withstand the pressure Acute contagious or communicable disease difference when flying at a normal cruising altitude of 30 000 feet.A Recent myocardial infarction compromise is reached when the cabin pressure approximates to Uncontrolled cardiac failure atmospheric pressure at an altitude of 5000-7000 feet.This has two effects:Recent cerebrl infarction (a) reduction of partial pressure of atmospheric oxygen; (b) expansion of Peptic ulceration with hoemorrhage within 3weeks gases within enclosed cavities.Simple abdominal operation within 10 days Reduced partial pressure-Pressure within the fuselage is maintained at Major chest surgery within 21 days about 80 kPa (600 mm Hg), resulting in an alveolar Po2 of 10 kPa Contagious or repulsive skin diseases (75 mm Hg).This reduces the haemoglobin oxygen saturation by only Wired fractures of mandible about 4%, so has little effect on the average person.Those with severe Mental illness without escort and sedation respiratory or cardiovascular disease, severe anaemia or sickle-cell disease, Pregnancies after 35th week (long journeys) or recent episodes of myocardial ischaemia and cerebral infarction are, or 36th week (short journeys) however, at risk and should travel only if it is essential.Smoking (active or Introduction of air into body cavities within 7days passive) during the flight will reduce haemoglobin oxygen saturation even further.Pregnant women over 35 weeks' gestation are not usually allowed12 MARCH 1983