预先心理应激对干舱模拟快速上浮脱险大鼠应激反应的作用

目的 观察预先心理应激对大鼠在模拟快速上浮脱险过程中应激反应的影响.方法 40只健康雄性SD大按数字随机表法鼠随机等分为4组:对照组、心理应激组、快速加减压组、预先心理应激+快速加减压组.通过建立快速上浮脱险动物模型,观察预先心理应激对该过程中大鼠应激反应的作用.结果 预先进行心理应激的动物在快速上浮脱险过程中,心率明显加快,血清肿瘤坏死因子(TNF-α)表达明显降低.结论 心理应激在模拟快速上浮脱险大鼠应激反应中起重要作用.

Abstract：

Objective To observe the effects of psychological pretreatment on the stress reaction of simulated fast buoyancy ascent escape in rats. Methods Forty healthy rats were randomly divided into 4 groups:the control group, the psychological stress group, the fast compression and decompression group, and the psychological stress pretreatment plus fast compression and decompression group. By developing the fast buoyancy ascent escape rat model with fast compression and decompression in a closed cabin, the effects of psychological pretreatment on the stress reaction were observed in the course of ascent. Results Hear t rate of the animals in the psychological pretreatment stress group was significantly higher than that in the control group (P＜0. 05), and the expression of serum TNF-α was significantly lower than that in the control group (P ＜ 0.05 ). Conclusions Psychological factor seemed to have positive effects on the stress reaction of the simulated fast buoyancy ascent escape in rats.     

MK10型脱险服上浮速度与时间变化规律的研究

在快速上浮脱险过程中,自由上浮是减压的唯一手段,当艇员处于大深度海水压力下时,上浮速度的变化曲线、平衡时间等成为艇员能否安全脱险的重要因素.笔者利用数值计算的方法,参考由试验结果得出的与水流条件有关的经验参数,对潜水员着MK10型脱险服时的上浮规律进行了建模分析,计算不同体质量艇员的上浮速度、加速度、平衡时间等,为MKIO型脱险服上浮规律的研究提供参考.     

预先心理应激对干舱模拟快速上浮脱险大鼠应激反应的作用

Objective To observe the effects of psychological pretreatment on the stress reaction of simulated fast buoyancy ascent escape in rats. Methods Forty healthy rats were randomly divided into 4 groups:the control group, the psychological stress group, the fast compression and decompression group, and the psychological stress pretreatment plus fast compression and decompression group. By developing the fast buoyancy ascent escape rat model with fast compression and decompression in a closed cabin, the effects of psychological pretreatment on the stress reaction were observed in the course of ascent. Results Hear t rate of the animals in the psychological pretreatment stress group was significantly higher than that in the control group (P＜0. 05), and the expression of serum TNF-α was significantly lower than that in the control group (P ＜ 0.05 ). Conclusions Psychological factor seemed to have positive effects on the stress reaction of the simulated fast buoyancy ascent escape in rats.     

模拟3～50 m快速上浮脱险训练潜艇艇员血压、脉率和呼吸频率的变化

目的 观察模拟快速上浮脱险训练时潜艇艇员生命指征的变化.方法 分别进行了3、10、30、50 m 4个深度69人次的快速上浮脱险训练,于训练前、训练后即刻及出舱后10 min分别测定艇员的血压、脉率和呼吸频率.结果 训练后即刻艇员的收缩压、舒张压、脉率及呼吸频率与进舱前比较,绝大部分指标有所增加,差异有统计学意义(P<0.01).在出舱后10 min各指标基本恢复正常.结论 模拟快速上浮脱险训练可增加艇员血压、脉率和呼吸频率,但均为一过性.本次脱险训练方案是安全可靠的.     

模拟3～50 m快速上浮脱险训练对潜艇艇员听力的影响

目的 探讨快速上浮脱险对潜艇艇员听力的影响.方法 10名潜艇艇员分别进行了3、10、30、50 m深度60人次模拟快速上浮脱险训练(3 m和10 m各2次).训练前后检查潜艇艇员双侧鼓膜,并进行电测听检查.结果 鼓膜末见异常,左耳在125、250 Hz,双耳在500、2000 Hz的听阈差异有统计学意义(P<0.05).结论 快速上浮脱险时的气压快速改变对潜艇艇员的听力有一定的影响,以低频听阈降低为主要表现.     

Oral administration of asparagine and 3-indolepropionic acid prolongs survival time of rats with traumatic colon injury

Background: Traumatic colon injury(TCI) is a common disease during wartime. Prolongation of posttraumatic survival time is an effective approach to patient outcome improvement. However, there is a lack of basic research in this field.This study aimed to elucidate the mechanisms underlying TCI progression and to develop novel regimens to buy time for TCI patients on the battlefield.Methods: A total of 669 Sprague–Dawley rats were used in this study. Surgical colon incision was performed to genera...     

胸部开放伤后海水浸泡对犬肺损伤程度的影响及肺表面活性蛋白A、B的变化

Objective To compare the extent of acute lung injury (ALl) and changes in surfactant proteins A (SP-A) and B (SP-B) induced by seawater and freshwater immersion following open chest injury in dogs. Methods The animal model was established by seawater and freshwater injection into the thoracic cavity after open chest injury. All the experimental animals were observed for 6 hours, during which blood gas analysis, levels of TNF-α and IL-8, contents of SP-A and SP-B in the lung and blood serum were measured at different time points. Pulmonary histopathology and SP-B immuno-histochemistry were measured after the animals were sacrificed at the end of the experiment. Results Both seawater immersion and freshwater immersion could induce hypoxemia, with the extent of hypoxemia for the seawater immersion group (SG) being obviously much severer than that of the freshwater immersion group (FG) (P < 0.05). The levels of IL-8 and TNF-α in blood serum and BALF of both experimental groups were significantly higher than those of the control group (CG) (P<0.05). Pulmonary pathological lesion was noted in both SG and FG, with that of SG being severer than that of FG. The levels of SP-A and SP-B in BALF in SG and FG all decreased significantly(P <0.05) ,while the levels of SP-A and SP-B in blood serum increased gradually (P < 0.05). Type Ⅱ alveolarepithelial cells with SP-B positive in the lung decreased in both experimental groups, with grey scale values being significantly lower than that of CG. And significant deviation was observed between SG and FG (P <0.05). Conclusions Pulmonary lesion induced by seawater immersion after open chest injury was severer than that induced by freshwater immersion.     

胸部开放伤后海水浸泡对犬肺损伤程度的影响及肺表面活性蛋白A、B的变化

Objective To compare the extent of acute lung injury (ALl) and changes in surfactant proteins A (SP-A) and B (SP-B) induced by seawater and freshwater immersion following open chest injury in dogs. Methods The animal model was established by seawater and freshwater injection into the thoracic cavity after open chest injury. All the experimental animals were observed for 6 hours, during which blood gas analysis, levels of TNF-α and IL-8, contents of SP-A and SP-B in the lung and blood serum were measured at different time points. Pulmonary histopathology and SP-B immuno-histochemistry were measured after the animals were sacrificed at the end of the experiment. Results Both seawater immersion and freshwater immersion could induce hypoxemia, with the extent of hypoxemia for the seawater immersion group (SG) being obviously much severer than that of the freshwater immersion group (FG) (P < 0.05). The levels of IL-8 and TNF-α in blood serum and BALF of both experimental groups were significantly higher than those of the control group (CG) (P<0.05). Pulmonary pathological lesion was noted in both SG and FG, with that of SG being severer than that of FG. The levels of SP-A and SP-B in BALF in SG and FG all decreased significantly(P <0.05) ,while the levels of SP-A and SP-B in blood serum increased gradually (P < 0.05). Type Ⅱ alveolarepithelial cells with SP-B positive in the lung decreased in both experimental groups, with grey scale values being significantly lower than that of CG. And significant deviation was observed between SG and FG (P <0.05). Conclusions Pulmonary lesion induced by seawater immersion after open chest injury was severer than that induced by freshwater immersion.     

兔肢体爆炸伤合并海水浸泡后在不同复温速率及维持浅低体温下机体炎症反应的特征

Objective To investigate effects of different rewarming rates and maintenance of light hypothermia on inflammatory response in rabbits after limb blast injury, coupled with seawater immersion. Methods First, the model of limb blast injury coupled with seawater immersion was reproduced [the animals were immersed to low body temperature of (31.0±0.5℃)]. Then, 24 adult rabbits were randomly divided into group Ⅰ [the rapid rewarming group, n=6, rewarmed to (38±0.5)℃ at a rate of (8.94±0.93)℃/h], group Ⅱ [the slow rewarming group, n=6, rewarmed to (38±0.5)℃ at a rate of (3.88±0.22)℃/h], group Ⅲ [another slow rewarming group, n=6, rewarmed to (38±0.5)℃ at a rate of (2.18±0.12)℃/h], and the H group [the hypothermia group, n =6, rewarmed to (34 - 35)℃ at a rate of (4.49±0.66)℃/h and kept at that temperature till termination of the experiment]. Regulation of ambient temperature and warm transfusion were used to restore body temperature to target levels and maintained there for 6 hours. Blood samples were taken at 5 different times, I.e. Pre-injury time(T0), post-immersion time (T1), the time when rewarming started (T2), 3 h after rewarming (T3), and 6 h after rewarming (T4). Tissue samples from heart, liver, intestinum, lung and kidney were also collected. Levels of TNF-α (tumor necrosis factor-α), IL-1β (interleukin-1β) and IL-6 (interleukin-6) in plasma and MPO (myeloperoxidase) in homogenate were detected. Results Following rewarming, TNF-α, IL-1β, IL-6 concentrations in the plasma of the animals in group Ⅰ and group H were significantly higher when compared with those of the animals in group Ⅱ and group Ⅲ (P<0.05, P<0.01), and MPO activity in homogenate was significantly higher when compared with that of the animals in group Ⅱ and group Ⅲ(P<0.01, P<0.05), and no statistical difference could be seen between group Ⅱ and Ⅲ (P>0.05). Conclusions Rapid rewarming and maintenance of light hypothermia could obviously elevate TNF-α, IL-1β, IL-6 concentrations in plasma and MPO activity in homogenate, following limb blast injury coupled with hypothermia induced by seawater immersion, while slow rewarming (with a rewarming rate of 2-4℃/h) could significantly inhibit TNF-α, IL-1β, IL-6 levels and PMN activity.     

兔肢体爆炸伤合并海水浸泡后在不同复温速率及维持浅低体温下机体炎症反应的特征

Objective To investigate effects of different rewarming rates and maintenance of light hypothermia on inflammatory response in rabbits after limb blast injury, coupled with seawater immersion. Methods First, the model of limb blast injury coupled with seawater immersion was reproduced [the animals were immersed to low body temperature of (31.0±0.5℃)]. Then, 24 adult rabbits were randomly divided into group Ⅰ [the rapid rewarming group, n=6, rewarmed to (38±0.5)℃ at a rate of (8.94±0.93)℃/h], group Ⅱ [the slow rewarming group, n=6, rewarmed to (38±0.5)℃ at a rate of (3.88±0.22)℃/h], group Ⅲ [another slow rewarming group, n=6, rewarmed to (38±0.5)℃ at a rate of (2.18±0.12)℃/h], and the H group [the hypothermia group, n =6, rewarmed to (34 - 35)℃ at a rate of (4.49±0.66)℃/h and kept at that temperature till termination of the experiment]. Regulation of ambient temperature and warm transfusion were used to restore body temperature to target levels and maintained there for 6 hours. Blood samples were taken at 5 different times, I.e. Pre-injury time(T0), post-immersion time (T1), the time when rewarming started (T2), 3 h after rewarming (T3), and 6 h after rewarming (T4). Tissue samples from heart, liver, intestinum, lung and kidney were also collected. Levels of TNF-α (tumor necrosis factor-α), IL-1β (interleukin-1β) and IL-6 (interleukin-6) in plasma and MPO (myeloperoxidase) in homogenate were detected. Results Following rewarming, TNF-α, IL-1β, IL-6 concentrations in the plasma of the animals in group Ⅰ and group H were significantly higher when compared with those of the animals in group Ⅱ and group Ⅲ (P<0.05, P<0.01), and MPO activity in homogenate was significantly higher when compared with that of the animals in group Ⅱ and group Ⅲ(P<0.01, P<0.05), and no statistical difference could be seen between group Ⅱ and Ⅲ (P>0.05). Conclusions Rapid rewarming and maintenance of light hypothermia could obviously elevate TNF-α, IL-1β, IL-6 concentrations in plasma and MPO activity in homogenate, following limb blast injury coupled with hypothermia induced by seawater immersion, while slow rewarming (with a rewarming rate of 2-4℃/h) could significantly inhibit TNF-α, IL-1β, IL-6 levels and PMN activity.     

Immersion suit insulation: the effect of dampening on survival estimates

Immersion suit leakage values were obtained from realistic testing of helicopter passenger immersion suits using eight subjects. Simulated helicopter underwater escape resulted in mean leakages of 198 +/- 103, 283 +/- 127, 203 +/- 179, and 45.7 +/- 31.6 g (mean +/- S.D.) when wearing four different immersion suits. Suit leakages obtained from a 20-min swim test to simulate vital in-water survival actions produced leakages of 213 +/- 224, 1398 +/- 691, 145 +/- 96.5, and 177 +/- 139 g (mean +/- S.D.). Dampening of undergarments during simulated helicopter travel at an elevated cabin temperature of 30 degrees C was 115 +/- 47.3 (mean +/- S.D.; n = 4) when wearing an impermeable suit and 19 +/- 16.7 g (mean +/- S.D.; n = 4) when wearing a vapour-permeable suit. The commensurate loss of insulation with the impermeable suit at the upper level of temperature could reduce clothing insulation by 17%. A reduction of less than 5% may result under similar conditions when wearing the permeable suit. The combined dampening effect of sweating, helicopter underwater escape, and performance of vital survival actions could result in a total dampening of 247-1712 g, depending on the type of suit worn. The respective loss of insulation would be 15% and 50% respectively. This could reduce, for the 10th percentile thin man, his survival time in water at 5 degrees C from 3.5 h to between 2.4 h and 1.1 h, respectively.     

Submarine escape trials 1999-2001--provision of medical support

Since the early 1960s all Royal Navy submarines have been fitted with an escape system comprising a single escape tower (SET) and submarine escape immersion suit (SEIS). This system enables escape from a submarine at a depth of 180 metres (1.9 MPa) provided that the submarine compartment is at a pressure of no greater than 1 bar (0.1 MPa). Due to a variety of causes which may include flooding and leakage of high pressure air systems it is the highly probable that the submarine compartment will be at a pressure in excess of 1 bar (0.1 MPa) at the time of the escape. To investigate and determine what constitutes a 'safe' maximum escape depth from any given compartment pressure (the safe to escape curve), a purpose built chamber complex, the Submarine Escape Simulator (SES) has been constructed at the QinetiQ, formerly the Defence Evaluation and Research Agency (DERA), Alverstoke site. Unlike escapes from a submarine where once released from the submarine the escapee's ascent can not be halted, within the SES it is possible to halt the ascent phase. This article describes the systems and procedures developed to enable medical support to be provided rapidly to a subject at any stage of the compression decompression profile. The article also provides details of the results to date that have been obtained from this work.     

模拟153m深度快速上浮脱险潜艇艇员血压、脉率和呼吸频率的改变

目的　观察大深度快速上浮脱险对潜艇艇员生命指征的影响。方法　分别进行了 3,10 ,6 0 ,80 ,10 0 ,12 0和 15 3m 4 0人次的快速上浮脱险实验 ,于脱险前和脱险后观察艇员血压、脉率及呼吸频率的改变。结果　脱险后 ,艇员收缩压、舒张压、脉率和呼吸频率均有所增加 ,在出舱后即刻为甚 ,大部分指标在出舱后即刻与进舱前相比较 ,差异有显著性 (P<0 .0 5 )或有非常显著性 (P<0 .0 1)。在出舱后 10min各指标基本恢复正常。在 10 0 ,12 0和 15 3m快速上浮脱险时第 1名艇员脉率改变持续较久 ,但最终也恢复正常。结论　快速上浮脱险可增加艇员血压、脉率和呼吸频率 ,但均为一过性。本次实验脱险方案是安全可靠的     

Acute lower limb ischemia associated with use of an immersion suit

External compression is a rare cause of acute lower limb ischemia. Workers required to wear immersion suits during helicopter simulation training are exposed to external compressive forces which can alter the hemodynamics in arterial bypass conduits. Herein a case of arterial thromboembolization to the lower limb following the wearing of an immersion suit, in a patient who had undergone arterial bypass surgery 13 yr previously is presented. The potential for this episode of acute leg ischemia being a direct result of the compressive forces exerted by the immersion suit and the possible implications for wearers of immersion suits following arterial graft surgery is discussed.     

G protection: interaction of straining maneuvers and positive pressure breathing

INTRODUCTION: G protection in the 39 Gripen aircraft is provided by a full coverage anti-G suit, a pressure-breathing system, and anti-G straining maneuvers (AGSM). The purpose was to study (1) the interaction of pressure breathing and AGSM while wearing an anti-G suit; and (2) the G-protective properties of the anti-G suit alone and in combination with the pressure-breathing system. METHODS: During rapid onset rate G-time profiles (< or =9 G), 10 subjects were investigated in 5 conditions: (I) sitting relaxed, without any G-protective garment; (II) sitting relaxed and wearing an anti-G suit; (III) sitting relaxed, wearing an anti-G suit, and pressure breathing; IV) wearing an anti-G suit and performing AGSM; and V) wearing an anti-G suit, pressure breathing, and performing AGSM. In supplementary experiments (n=9), the share of the anti-G suit protection afforded by the abdominal bladder was investigated. RESULTS: G tolerance was 3.4 Gz (range: 2.8-4.3) in condition I, > or = 6.5 Gz (4.5-9.0) in II, > or = 8.0 Gz (6.5-9.0) in III, > or = 8.9 Gz (8.5-9.0) in IV and > or = 9.0 Gz (8.5-9.0) in V. In the supplementary experiments, the anti-G suit afforded a 2.8-G protection, a third of which was contributed by the abdominal bladder. In the relaxed state, pressure applied to the airways was transmitted undistorted to the intrathoracic space. During AGSM, intrathoracic pressure rose to 10-14 kPa, regardless of whether AGSM was performed with or without pressure breathing. DISCUSSION: AND CONCLUSIONS: The anti-G suit and the pressure breathing system provide G protection of > or = 4.6 G, of which the anti-G suit contributes about 3.0 G. The C-protective properties of the anti-G suit and those of pressure breathing appears to be additive, whereas the G protection afforded by pressure breathing does not add to that provided by AGSM.     

Effects of submarine escape training on the pulmonary function and carbon dioxide retention in the escape

Objective Fast buoyancy ascent escape used in submarine escape is the most probable choice of survival in case of a submarine accident.Rate of success for escape depends very much on the extent of training,in spite of the fact that rapid compression and decompression pose great challenges to the human body in terms of enormous stresses.To minimize stresses experienced during sub escape training has always been a research subject for us.Lungs are susceptible to rapid change in pressure during escape.Dynamic pulmonary function and the end-tidal PCO2 ( PETCO2 ) might be the best indicator for its effect on the pulmonary function of the submarine escapee.Methods Five male navy divers received submarine escape trainings,at different depths from 3-60 m.They were compressed at different rates (with pressure doubled every 20 s or 30 s),in the simulated submarine escape tower located in the Naval Medical Research Institute.The gas of end-expiration was collected immediately after escape,respiratory rate (RR) and dynamic pulmonary function were closely monitored,and PETCO2 was determined with the mass spectrometer.Results Experimental results showed that forced expiratory volume in 1 second (FEV1.0) tended to increase with increasing depth,and that it increased significantly at 50 m and 60 m,when compared with the basic data (P ＜ 0.05 ),and it was coupled with a decrease in forced expiratory flow at 25 ％ ( FEF25％ ),indicating that it had certain effect on the function of small airways.PETCO2 and RR all elevated markedly following escapes.No significant differences could be seen in RR following escapes at various depths.PETCO2 and depth ( r =0.387,P ＜ 0.01 ) were positively correlated with compression rate ( r =0.459,P ＜ 0.01 ) and RR ( r =0.467,P ＜ 0.01 ).CO2 retention might be attributed to pulmonary ventilation disorder induced by rapid changes in pressure.PETCO2 was within normal range,following escapes at various depths,suggesting that increased RR might be induced by stresses rather than CO2 retention.No significant differences could be noted in PETCO2 and RR,following escapes with different compression rates,indicating that lower compression rate might not necessarily mitigate stresses of the body.Conclusions Based on the pulmonary reaction experienced by the trainees,it was recommended that submarine escape training be conducted at a depth no deeper than 50 m,so that possible airway lesion might be minimized.The benefit of lower compressing rate at shallower escape depths remained to be identified.     

50m实艇快速上浮脱险时艇员应激功能的变化

目的 探讨50 m实艇快速上浮脱险时艇员应激功能的变化.方法 结合部队训练进行了4人次50 m实艇快速上浮脱险试验,分别于脱险前后观察艇员血压、心率及唾液中皮质醇、分泌型免疫球蛋白A浓度的变化.参训艇员在脱险后30 min内填写美国国家航空航天局任务负荷指数(NASA-TLX)量表.结果快速上浮脱险后艇员收缩压(138.75±8.77) mm Hg,与脱险前[(125.25±8.92)mm Hg]比较显著升高(P＜0.01);唾液皮质醇浓度[(5.35±2.16)μg/L]比脱险前[(3.30±1.78)μg/L]显著增加(P＜0.05);舒张压、心率和唾液分泌型免疫球蛋白A浓度变化无统计学意义.NASATLX量表结果表明,主观心理负荷分值总分和焦虑指数变化趋势基本一致.结论 实艇快速上浮脱险引起机体应激水平增强,可能主要由艇员认知评价导致的焦虑感增高引起.