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Biomedical subjects

O I Molvaer

Publications and source records attributed to O I Molvaer.

9 recordsLinked to original sources

[The Norwegian Antarctic expedition 1989-1990--medical contingency, work and research].

Antarctica is the world's coldest, driest, highest and most windy continent. The ice may reach a thickness of nearly five km, and the greater part of the world's fresh water is bound in this ice cap. The lowest temperature ever measured is -90 degrees C. The weather during this summer expedition was pleasant, and the temperature seldom fell below -30 degrees C. The 35 persons in the land party included two physicians and one nurse. No serious injury or disease occurred. The participants seemed experience an increase in lean body weight and loss of fat during five weeks in tents. Extensive data were collected for medical-psychological projects on immunology, adaptation to cold, exhaustion from cold and stress. Some results have been published in separate reports.

Adaptation, Physiological

Vestibular problems in diving and in space.

On firm ground our sense of balance is supplied by super abundant input from several sensoric sources. In other environments insufficient or conflicting input may cause vestibular problems. In diving, vertigo may be caused by a variety of influences, like sensory deprivation, optokinetic illusion, asymmetric vestibular stimulation, inner ear barotrauma, decompression sickness, breathing gas toxicity, high pressure neurological syndrome, sea sickness and intense noise. During space flight some of the mentioned mechanisms may contribute to vestibular problems, although space motion sickness being the main cause of concern in this connection.

Barotrauma

Ear damage due to diving.

Diving injury may affect all parts of the ear during all types of diving. Divers are regularly exposed to noise and 120 dB(A) is measured during ventilation of a hyperbaric chamber. Ear canal squeeze, possibly with drum perforation, may give a transient conductive hearing loss. Middle ear squeeze, possibly with drum perforation, also gives a transient conductive loss. Inner ear barotrauma, possibly with perilymph fistula, most often results in transient vertigo and lasting sensorineural high tone loss, often resembling a noise-induced loss. Decompression sickness and gas embolism can also damage the inner ear. A change of breathing gas during deep diving has damaged the labyrinth, most likely due to counter diffusion. The authors have seen two cases of over window perilymph fistula resulting from diving. One of them also suffered a burst ear drum on the same side. His hearing returned to normal after surgical repair.

Barotrauma

The size of the middle ear and the mastoid air cell.

The total volume for the middle ear and mastoid air cells was measured in 55 temporal bones with normal ear drums from a Norwegian post-mortem material. The measurements were made by an acoustic method and checked by means of fluid filling induced by vacuum pumping. As a measuring fluid X-ray contrast medium was employed so that the degree of filling could be examined by X-ray. The volume varied between approximately 2--22 cm3 with an average round 6,5 cm3.

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