1/6. Biophysical basis for inner ear decompression sickness.Isolated inner ear decompression sickness (DCS) is recognized in deep diving involving breathing of helium-oxygen mixtures, particularly when breathing gas is switched to a nitrogen-rich mixture during decompression. The biophysical basis for this selective vulnerability of the inner ear to DCS has not been established. A compartmental model of inert gas kinetics in the human inner ear was constructed from anatomical and physiological parameters described in the literature and used to simulate inert gas tensions in the inner ear during deep dives and breathing-gas substitutions that have been reported to cause inner ear DCS. The model predicts considerable supersaturation, and therefore possible bubble formation, during the initial phase of a conventional decompression. Counterdiffusion of helium and nitrogen from the perilymph may produce supersaturation in the membranous labyrinth and endolymph after switching to a nitrogen-rich breathing mixture even without decompression. Conventional decompression algorithms may result in inadequate decompression for the inner ear for deep dives. Breathing-gas switches should be scheduled deep or shallow to avoid the period of maximum supersaturation resulting from decompression.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
2/6. Ultrastructural aspects of bubble formation in human fatal accidents after exposure to compressed air.Electron microscopic investigations were performed on samples of human tissue obtained from subjects following fatal decompression sickness, associated with hyperbaric air-therapy. Intra- and extracellular gas bubbles of varying size were identified throughout the entire body. Each bubble was covered by an osmiophilic non-homogeneous coat of cloudy and flocculent material, native to its specific locality. This envelope measured from 30 to 560 Angstroem-units in thickness. association of this covering with an electrokinetic zonal activity, detected biophysically by Lee and Hairston (1971) is assumed. We consider this surface coat prevents nitrogen from being eliminated via the blood-lung barrier.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
3/6. Otologic and otoneurologic injuries in divers: clinical studies on nine commercial and two sport divers.In the past two decades, we have seen a great increase in the number of injuries from commercial and sport diving. During this time, our knowledge of the physiology and pathophysiology of diving has also increased. As a result, we now can accurately diagnose and successfully treat many of these injuries. Of the commercial and sport divers examined as pateints in the Department of otolaryngology at the University of texas Medical Branch in Galveston, Tex., between September, 1974, and May, 1975, 11 showed positive otologic and otoneurologic findings which are reported herein. One patient was surgically explored for an oval window fistula. In localizing and classifying these injuries, we have utilized extensive and broad-based test batteries, which include complete history, otologic and otoneurologic physical examination, audiometry, a central auditory test battery, and a vestibular test battery. These tests are described. The findings in each of the divers are illustrated and analyzed. This article further describes the use of these test batteries, which were employed to localize otoneurologic pathology in this sample of injured divers. Based on these cases, we have expanded and modified Edmonds' classification of the etiology of vertigo related to diving. We feel that the test batteries which we describe, or similar tests, should be part of the otologic and otoneurologic workup of injuries divers.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
4/6. Fatal pulmonary decompression sickness: a case report.A 51-year-old civilian pilot flying a high performance aircraft for the USAF presented for medical attention approximately 1.5 hours after developing substernal chest pain and dyspnea while flying unpressurized at FL 280 (8,534 meters) for 30 minutes. In spite of recompression about 3 hours later, the pilot expired while ascending from 6 atmospheres, 2.5 hours into the dive. This represents the first reported fatality due to altitude-induced decompression sickness since 1959. Pathologically, this case is similar to cases presented in the past. In addition, this case serves to reemphasize many of the "risk factors" for decompression sickness, especially age and obesity. Furthermore, the evidence presented points to maintaining only the highest standards of physical health in those who fly high performance aircraft.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
5/6. Factitious decompression sickness.The diagnosis of decompression sickness is made largely by history; there are few physical findings and no radiographic or laboratory tests to support the diagnosis. We present three cases of factitious decompression sickness in which patients fabricated an appropriate history and underwent compression therapy. Due to the potential severity of decompression sickness and the relative safety of compression therapy, the initiation of therapy must not be delayed in a case of decompression sickness. Once therapy is begun, investigation into the particulars of a suspicious case can be made.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
6/6. Oxy-helium treatment of severe spinal decompression sickness after air diving.spinal cord injury in DCS after air diving is relatively frequent and often has late sequelae. U.S. Navy oxygen tables are sometimes not satisfactory. The advantage of using helium in these cases is based theoretically on its physical properties and has been demonstrated in animal models. We have introduced the Comex-30 (CX-30) oxy-helium table as an integral part of our treatment protocol for severe spinal DCS. We summarize here our clinical experience with seven cases. A case was considered severe if clinical assessment suggested progressive neurologic injury to the spinal cord or roots. Except for one case, the initial treatment was CX-30 followed by HBO sessions as indicated. Of the seven patients treated, five made a full recovery and the remaining two were left with mild neurologic sequelae.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |