Persons with poor eustachian tube function (eg, congenital narrowness or acquired mucosal edema) may be unable to equalize the barometric stress exerted on the middle ear by air travel, rapid altitudinal change, or underwater diving The problem is generally most acute during airplane descent, since the negative middle ear pressure tends to collapse and block the eustachian tube, causing pain Several measures are useful to enhance eustachian tube function and avoid otic barotrauma The patient should be advised to swallow, yawn, and autoinflate frequently during descent Oral decongestants (eg, pseudoephedrine, 60–120 mg) should be taken several hours before anticipated arrival time so that they will be maximally effective during descent Topical decongestants such as 1% phenylephrine nasal spray should be administered 1 hour before arrival For acute negative middle ear pressure that persists on the ground, treatment includes decongestants and attempts at autoinflation Myringotomy (creation of a small eardrum perforation) provides immediate relief and is appropriate in the setting of severe otalgia and hearing loss Repeated episodes of barotrauma in persons who must fly frequently may be alleviated by insertion of ventilating tubes Underwater diving may represent an even greater barometric stress to the ear than flying Patients should be warned to avoid diving when they have an upper respiratory infection or episode of nasal allergy During the descent phase of the dive, if inflation of the middle ear via the eustachian tube has not occurred, pain will develop within the first 15 feet; the dive must be aborted In all cases, divers must descend slowly and equilibrate in stages to avoid the development of severely negative pressures in the tympanum that may result in hemorrhage (hemotympanum) or in perilymphatic fistula In the latter, the oval or round window ruptures, resulting in sensory hearing loss and acute vertigo During the ascent phase of a saturation dive, sensory hearing loss or vertigo may develop as the first (or only) symptom of decompression sickness Immediate recompression will return intravascular gas bubbles to solution and restore the inner ear microcirculation Tympanic membrane perforation is an absolute contraindication to diving, as the patient will experience an unbalanced thermal stimulus to the semicircular canals and may experience vertigo, disorientation, and even emesis