减压病

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自高压环境骤然转至低压环境时,由於体内有气泡形成而引起的机体生理变化。非增压座舱式飞机驾驶员、潜水夫和沈箱工人最易罹患。在常压下人体组织内容有少量与空气成分相同的气体,当驾驶员升向高空时,外界压力降低,这些气体便脱离溶解状态。如果上升很慢,则气体有足够时间自组织弥散至血流内,然後进入呼吸道自体内呼出。而下沈得愈快,气体(主要是氮气〔nitrogen〕)会在组织内形成气泡。若气泡在脑、脊髓或周围神经形成,便可引起麻痹和惊厥(潜水夫麻痹)、肌肉协调障碍和感觉异常(潜水夫蹒跚)、麻木、恶心、言语缺陷及人格改变。当气泡在关节积聚时,通常有关节剧痛。若见剧咳和呼吸困难(称为气窒),便说明呼吸系统内有氮气泡。严重的话会休克(shock)。将患者放在高压室(hyperbaric chamber)内先行加压,然後逐渐减压常可达到解救目的,但对已形成的组织损害无效。

decompression sickness

orcaisson diseaseHarmful effects of rapid change from a higher- to a lower-pressure environment. Small amounts of the gases in air are dissolved in body tissues. When pilots of unpressurized aircraft go to high altitudes, or when divers breathing compressed air return to the surface, external pressure on the body decreases and the gases come out of solution. Rising slowly allows the gases to enter the bloodstream and be taken to the lungs and exhaled; with a quicker ascent, the gases (mostly nitrogen) form bubbles in the tissues. In the nervous system, they can cause paralysis, convulsions, motor and sensory problems, and psychological changes; in the joints, severe pain and restricted mobility (the bends); in the respiratory system, coughing and difficulty breathing. Severe cases include shock. Recompression in a hyperbaric chamber followed by gradual decompression cannot always reverse tissue damage.

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