太空减压病的发病率与预防

通过对太空减压病同高空减压病进行比较，阐明太空减压病应由高空减压病独立出来的必要性。太空减压病与高空减压病的病因学和发病机理相同，但引起发病率有不同的规律（包括影响因素等）和各自独特的特征。为了得对太空减压病有一个系统明确的认识，利于更有效地制定预防方案和建立学科，太空减压病应成为独立的专业术语。     

高空爆炸减压事件对飞行人员心理功能的影响

飞机座舱高空急速减压严重损害飞行人员的机体功能,致发高空减压病。为了探讨经历高空爆炸减压事件并患有高空减压病飞行人员心理功能改变的性质、范围和特点,我们对在一次训练飞行中因座舱爆炸减压发生高空减压病的     

减压病:用多普勒可测微气泡作个体危险性的Bayes分析

前言有几种个体体质因素是对高空减压病危险性有影响的。本文中作者采用Bayes氏理论来评估低气压情况下减压病的个体危险性因素。方法应用美国国家航空航天局屈肢痛数据库(n=516)的资料,以微气泡Ⅲ级作为阳性,首次检验了用多普勒可测微气泡预测减压病症状的诊断准确性。在参加本试验的一些受试者(n=164)中采用个体体质因素的资料按逻辑斯蒂回归模式估算其先验高空减压病危险性,再利用Bayes氏理论由多普勒检测结果计算个体减压病后     

静脉气体栓子形成在高空减压病危险性的统计学气泡动力学模型中的重要性

前言根据不断增加的减压病经验建立的精确内推或外推的分析工具将更为准确地评估和处理各种复杂高空暴露方案高空减压病的危险性。已研制出各种气体和气泡动力学(GBD)模型作为这种分析工具。减压病的危险性是被作为试管模型中各种给定方案下得出的气泡体积的函数。在当前的工作中是把组织气体消失看作是组织气体进入血管内变成静脉气体栓子来验证模型增加的好处。方法用极大似然对1194名     

循环气泡原发点与减压病症状部位的相关

前言高空飞行员的减压病症状通常直接或间接归因于关节、组织或体液中气泡的存在。本研究的目的是找出明显的静脉气体栓子源与症状部位之间的关系。方法查对了阿斯特朗实验室的减压病低气压研究数据的记录。这些记录包含从1983年到1995年中的1471例暴露在9000 ft～35000 ft(2743 m～10668 m)高空3 h～8 h受试者的数据。把减压病症状出现或是结束暴露作为记录的终点,所有受试者均用     

高空迅速减压飞行人员的临床诊治和医学鉴定

目的 探讨飞行中高空迅速减压飞行人员的临床诊治经验和医学鉴定方法。方法 回顾分析近10年来空军发生的5起19人次高空迅速减压病例资料,暴露高度为8300至10 000 m. 结果 ①5起高空迅速减压中有3起10人（A组）返航后未经休息吸氧和高压氧治疗,其中7人发生了Ⅱ型高空减压病,发病率为70%,另2起9人（B组）返航后及时休息吸氧并送就近医院作高压氧治疗,均未发生高空减压病,两组高空减压病发生率有显著性差异（P〈0.01）.②两组对比分析发现,除了已明确的迅速减压时的高度外,在本组资料中个体敏感性、减压后高空缺氧以及空中和返航后的处置是否得当是影响发病的重要因素.③所有发病者经治疗均重返飞行岗位,但发病后治疗不适当或飞行员出现心理障碍会延长康复时间。 结论 高空迅速减压可对飞行人员造成显著的心理和生理影响,并且发生高空减压病的危险很大,减压后空中及返航后处置是否得当是影响病情发展的重要因素。     

美国高空减压病专题讨论会及近年工作简介

介绍了美国高空减压病专题讨论会的主要内容，并对1990年以来在该领域的工作进行了简要的回顾。会议主要讨论了有关①提高体内气泡的检测技术水平；②卵圆孔未闭合在发病过程中的作用；③新的减压病分型标准；④神经系统检查的重要性；⑤预防方法的改进提高；⑥患病飞行员的放飞标准及航天飞行中减压病的预防等内容，反映了国外目前及日后研究的主要方向，对国内高空减压病的基础研究和临床工作具有一定参考价值。     

空军飞行人员高空减压病7例

高空减压病是比较典型的航空病,一般在高空意外减压而致病,当飞行人员直接暴露于低压缺氧环境时,在组织、体液中溶解的氮气被离析出来,在血管内形成气泡,有可能栓塞血管,严重者危及生命安全。该病在世界航空界及国内时有报道。其诊断主要依据是高空低气压暴露史、典型的临床表现以及相关辅助检查。现就我院收治的二起7例高空减压病进行报道。     

高空舱复习性训练暴露后的减压病

前言 高空减压病(DCS)是已知的低压舱暴露危险。其危险性随暴露高度的增加而增加。另外,在有些研究中发现在舱内的观察员和女性发生减压病的危险     

加拿大空军航空医学训练

加拿大空军传统上采用低压舱进行飞行人员的航空医学训练。尽管这种训练的益处显而易见，但是高空减压病的高发率在加拿大空军还是引起了关注。当前低压舱缺氧训练的最大高度是30000英尺，高空减压病的发病率是千分之七点四八。2003年11月之前的缺氧训练模式有两种：模式1暴露高度为25000英尺，相应的减压病发病率为千分之10．66；     

Decompression schedule optimization with an isoprobabilistic risk of decompression sickness

INTRODUCTION: Divers use decompression schedules to reduce the probability of occurrence of decompression sickness when returning to the surface at the end of a dive. The probability of decompression sickness resulting from these schedules varies across different dives and the models used to generate them. Usually the diver is unaware of this variance in risk. This paper describes an investigation into the feasibility of producing optimized iso-probabilistic decompression schedules that minimize the time it takes for a diver to reach the surface. METHODS: The decompression schedules were optimized using the sequential quadratic programming method (SQP), which minimizes the ascent time for a given probability of decompression sickness. The U.S. linear-exponential multi-gas model was used to calculate an estimate of the probability of decompression sickness for a given dive. In particular 1.3-bar oxygen in helium rebreather bounce dives to between 18 m and 81 m were considered and compared against the UK Navy QinetiQ 90 tables for a similar estimate of probability of decompression sickness. RESULTS: The SQP method reliably produced schedules with fast and stable convergence to an optimized solution. Comparison of the optimized decompression schedules with the QinetiQ 90 schedules showed similar stop times for shallow dives to 18 m. For dives with a maximum depth of 39 m to 81 m, optimizing the decompression resulted in savings in decompression time of up to 30 min. CONCLUSIONS: This paper has shown that it is feasible to produce optimized iso-probabilistic decompression tables given a reliable risk model for decompression sickness and appropriate dive trials.     

Altitude decompression sickness in a pilot wearing a pressure suit above 70,000 feet

U-2 pilots are at an increased risk of decompression sickness compared with other aviators in the U.S. Air Force. This is due to the extreme altitudes at which the missions take place. Presented here is a case of decompression sickness that occurred in a U-2 pilot who was wearing a full-pressure suit while flying at an altitude greater than 70,000 ft, with a pressurized cabin altitude of 29,200 ft. This case demonstrates the continued need for pilot education and awareness of DCS risk factors and symptoms.     

A case of decompression sickness at 2,437 meters (8,000 feet)

Among aviators, decompression sickness is a condition that occurs almost exclusively at altitudes above 6,098 m (20,000 ft). Several reports have been published describing the development of decompression sickness after altitude exposures of 3,049 to 4,878 m (10,000-16,000 ft). In most of these cases, the affected individual had a previous history of pain in the involved area due to prior trauma or surgery, or had other risk factors for decompression sickness, such as obesity. Few of these reports have confirmed the presence of decompression sickness by a test of pressure. A case is reported here of multiple joint pains developing after a rapid decompression at 2,439 m (8,000 ft), which improved during descent and rapidly resolved with recompression therapy. There was no prior history of joint pain, trauma, or diving. A brief discussion of decompression sickness is included.     

Relationship of menstrual history to altitude chamber decompression sickness

Records at the USAF School of Aerospace Medicine, Division of Hyperbaric Medicine, were reviewed to determine the relationship between the incidence of altitude chamber decompression sickness (DCS) in females and menstrual history. The study period spans 11 years, from January 1978 to December 1988. There were 81 records suitable for study. A significant inverse linear correlation was noted between the number of days since the start of last menstrual period and the incidence of DCS. This relationship was noted with both Type I and Type II DCS. Lack of information on the population at risk precluded an analysis of the effects of birth control pills on this phenomenon. The underlying mechanism for the correlation between menstrual cycle and susceptibility to development of DCS is unknown. We conclude that women are at higher risk of developing altitude related decompression sickness during menses, with the risk decreasing linearly as the time since last menstrual period increases.     

The risk of altitude decompression sickness at 12,000 m and the effect of ascent rate

INTRODUCTION: Loss of aircraft cabin pressurization can result in very rapid decompression rates. The literature contains reports of increased or unchanged levels of altitude decompression sickness (DCS) resulting from increasing the rate of decompression. We conducted two prospective exposure profiles to quantify the DCS risk at 12,192 m (40,000 ft), and to determine if there was a greater DCS hazard associated with a much higher rate of decompression than typically used during past DCS studies. METHODS: The 63 human subjects participated in 80 altitude chamber decompression exposures to a simulated altitude of 12,192 m (2.72 psia; 18.75 kPa) for 90 min, following preoxygenation with 100% oxygen for 90 min. Half of the subject-exposures involved an 8-min decompression (1,524 mpm; 5,000 fpm) and the other half experienced a 30-s decompression (mean of 24,384 mpm; 80,000 fpm). Throughout each ascent and exposure, subjects were seated at rest and breathed 100% oxygen. At altitude, they were monitored for precordial venous gas emboli (VGE) and DCS symptoms. RESULTS: The higher decompression rate yielded 55.0% DCS and 72.5% VGE and the lower rate produced 47.5% DCS and 65.0% VGE. Chi square and log rank tests based on the Kaplan-Meier analyses indicated no difference in the incidence or onset rate of DCS or VGE observed during the two profiles. CONCLUSION: Decompression rate to altitude up to 24,384 mpm was found not to have an effect on DCS risk at altitude. However, research is needed to define the DCS risk with decompression rates greater than 24,384 mpm. It was also found that the onset time to DCS symptoms decreases as altitude increases.     

航天减压病易感性检测的研究

目的 为航天减压病易感性的检测提供有关参数。方法 ４３人进行低压舱实验。结果 安静状态下，高空减压病的发生与年龄、预吸氧时间及某些生理指标关系密切；在同样吸氧、减压条件下，年龄较大者（３０￣３６岁）比年轻者（１９￣２０岁）体脂高、血胆固醇高；实验前、后尿去甲肾上腺素增量大的减压病的发生率显著增高。在同样减压条件下，年龄相同、预吸氧时间长的，减压病的发生率明显减少或不发生。结论 初步拟定航天减压病易     

About the problem of high-altitude decompression sickness and its treatment

It gives the idea of the modern conception of intravascular aerogenesis. It reviews the modern methods of diagnostics and treatment of altitude decompression sickness and gives guidelines to the doctor's actions by rendering medical aid in case of altitude decompression sickness.     

Intracardial bubbles during decompression to altitude in relation to decompression sickness in man.

Doppler ultrasound was used in five subjects to detect intracardial gas bubbles during decompressions to altitude. At a simulated altitude of 8,000 m, neither intracardial bubbles nor symptoms of decompression sickness occurred. At 9,000 m, bubbles were registered in two subjects, one of which had questionable bends. At 11,500 m, bubbles were registered in all but one subject and two had bends. The three subjects who had not gotten bends were exposed to an air-breathing period of 30 min or, in one case, even 45 min at 2 ATA, for extra nitrogen loading, followed by decompression to 11,500 m. These subjects had heavy showers of bubbles followed by bends. In all cases with decompression sickness during the decompressions to altitude, intracardial bubbles were registered prior to the appearance of symptoms. The technique may be used in studies of decompression sickness without provoking actual symptoms, thus making the studies safer.     

Hyperbaric oxygen pre-breathe modifies the outcome of decompression sickness.

Deep sea divers, aviators and astronauts are at risk of decompression sickness when the ambient pressure reductions exceed a critical threshold. Venous bubbles associated with decompression sickness have the potential to react with the vascular membrane and adjacent blood products, eliciting an inflammatory cascade. Preventive measures usually involve careful decompression procedures to avoid or reduce bubble formation. De-nitrogenation with 100% oxygen pre-breathing as a preventive measure has been well established at least in altitude decompression exposures. The objective of this study was to determine the physiological and biochemical effects of Hyperbaric Oxygen Pre-breathe (HBOP) upon decompression from a hyperbaric exposure. Male Sprague-Dawley rats were randomly assigned to one of eight groups. Two experimental groups received HBOP at 1 and 18 hours prior to decompression, as compared with ground level oxygen or non-treated groups that still experienced decompression stress, and the associated non-decompressed controls. The results showed decreased extravascular lung water (pulmonary edema), bronchoalveolar lavage and pleural protein and arterial, broncho-alveolar lavage, and urine leukotriene E4 (LKE4) levels in both the 1Hr and 18Hr HBOP decompressed rats compared to non-oxygenated decompressed rats, as well as a decreased overall expression of signs of decompression sickness. This study indicates that HBOP-treated rats exhibit fewer signs and complications of decompression sickness compared with non-treated or ground level oxygen treated rats.     

Intracardial gas bubbles of altitude after negative pressure breathing.

The influence of negative pressure breathing on the appearance of intracardial gas bubbles at a subsequent decompression to altitude was investigated in five subjects using the precordial Doppler ultrasound technique. Every subject was tested for a suitable exposition that, after 30 min oxygen breathing at surface, caused both intracardial bubbles and decompression sickness. An identical exposition followed a week later, except that oxygen breathing at the surface now included negative pressure breathing. In all cases, negative pressure breathing caused a delay of the onset of both intracardial bubbles and bends and, in some cases, neither bubbles nor bends appeared at all. The total amount of bubbles was always less after negative pressure breathing. Thus, negative pressure breathing in connection with decompression may reduce the amount of intracardial bubbles and the risk of decompression sickness. This may be of importance in diving procedures and in the construction of diving devices.