复杂压力暴露条件下从失事潜艇快速上浮脱险后余氮张力的初步探讨

目的 探讨失事潜艇艇员在高压下暴露并从失事潜艇快速上浮脱险后体内余氮张力的计算方法.方法 对失事潜艇脱险过程进行分解,采用微积分等方法,建立脱险艇员出水时体内氮张力值的理论计算公式,并将此氮张力值换算成相对饱和深度.结果 建立的理论计算公式可以计算在7、12 m饱和后,在不同深度脱险时体内余氮张力值对应的相对饱和深度.结论 本研究建立的理论计算公式可为减压病的预测提供参考,为分析复杂压力暴露后快速上浮脱险方法的安全性提供理论依据.     

快速上浮脱险潜艇艇员脑血管血流动力学改变研究

目的：观察快速上浮脱险潜艇艇员脑血管血流动力学的变化。方法：应用彩色多普勒超声,对参加模拟3～30m快速上浮脱险试验艇员8例进行颈动脉及椎动脉血流动力学监测。结果：双侧颈总动脉、颈内动脉及椎动脉的阻力指数和搏动指数随着试验深度的变化均差异不显著（P〉0．05）。结论：浅深度快速上浮脱险对脑血管血流动力学无显著影响,进行类似上浮脱险训练较为安全。     

模拟大深度潜艇艇员快速上浮脱险致减压病大鼠模型的建立

目的 建立稳定的模拟大深度潜艇艇员快速上浮脱险致减压病大鼠模型.方法 雄性SD大鼠80只,采用数字表法随机分为4组:正常对照组,高压暴露2、4、8 min组,每组20只.高压暴露各组置于空气加压舱内以2t/8指数速率加压至150 m,分别停留2、4、8 min后,以3m/s匀速减压至常压出舱.观察各组大鼠行为学和肺、脑、脊髓组织病理结果.结果 高压暴露2、4、8 min组大鼠出舱后均出现竖毛、搔抓、行动迟缓、反应性差等行为状态.病理结果显示,大鼠肺泡和肺间质及脊髓组织出血明显,细胞水肿,脑组织未见明显改变.暴露2、4、8 min组大鼠发病率分别为20.0％、55.0％、10.0％,死亡率分别为0、20.0％、85.0％,3个高压暴露组大鼠发病率及死亡率差异均有统计学意义(P＜0.01).由于8 min方案暴露时间过长,制备的大鼠模型出舱后死亡率较高,而2 min方案高压下停留时间不够,制备的大鼠模型发病率较低,高压暴露4 min方案大鼠死亡率低且减压病发病率高.结论 本实验以高压暴露4 min方案成功地建立了大深度潜艇艇员快速上浮脱险致减压病动物模型.     

模拟快速上浮脱险对大鼠肝脏糖皮质激素受体mRNA表达的影响

目的观察模拟200m快速上浮脱险对大鼠肝脏糖皮质激素受体（GR）转录水平表达的影响，探讨这一应激方式对机体的损伤机制。方法sD大鼠30只，随机分为5组：正常对照组6只，模拟快速上浮脱险后1、2、4、24h各6只。用RT—PCR方法检测大鼠肝脏GRmRNA表达水平。结果GRmRNA在大鼠肝脏中多量表达；模拟快速上浮脱险后其表达水平迅速降低（P〈0．01），以后随时间延长逐渐恢复，24h基本恢复至正常。结论模拟快速上浮脱险可一过性下调肝脏GRmRNA表达。     

模拟快速上浮脱险对潜艇艇员咽鼓管通气功能的影响

目的 测试模拟快速上浮脱险中潜艇艇员咽鼓管开放功能的变化,为潜艇艇员快速上浮脱险提供合理的医学保障和依据.方法 应用ET-100咽鼓管开放功能测试仪测试5名潜艇艇员在3、10 m水加压前后,10、30 m(分别以t/30、t/20速率)气加压前后,50、60 m以t/20速率气加压前后,分别检测艇员吞咽时咽鼓管(eustachian tube,ET)开放功能,并作统计学处理.结果 3、10 m水加压后ET平均开放度下降8.09%、9.79%(P>0.05);以t/30、t/20速率,10 m气加压后ET平均开放度下降11.51%,6.89%(P>0.05),30 m气加压后ET平均开放度下降58.3%、92.8%(P<0.01);以t/20加压速率进行的50、60 m气加压后ET平均开放度下降14.51%、7.56%(P>0.05).结论 各深度快速加减压对潜艇艇员咽鼓管开放功能影响差别不大,不会由于加压方式、加压速率不同而导致咽鼓管开放等级产生显著变化;快速加减压的耐受性越强,ET主动开放通气度越大.     

N-乙酰半胱氨酸对快速上浮脱险致减压病大鼠心肺组织的影响

目的：研究N－乙酰半胱氨酸（ NAC）对快速上浮脱险致减压病大鼠心肺组织的影响。方法雄性SD大鼠80只,随机分为4组,每组20只。实验组于进舱前1 h通过腹腔注射NAC溶液（注射剂量分别为250、500和1000 mg／kg）,对照组于进舱前1 h腹腔注射相同体积生理盐水。压缩空气以指数速率2t／7加压至1．5 MPa,停留4 min后匀速减压至常压出舱。出舱后即观察大鼠行为学表现并统计存活率,出舱后0．5 h活杀大鼠,取心、肺组织,观察其病理变化。结果 NAC 500 mg／kg组大鼠存活率（90％）显著高于对照组（65％）（P＜0．05）;对照组大鼠肺泡结构大面积破坏融合,肺泡腔内可见红细胞渗出;心肌纤维水肿、变性,断裂明显。而NAC组大鼠肺泡壁增厚程度和心肌纤维水肿程度均较对照组轻微。结论 NAC可通过减轻大鼠心肺组织的损伤和炎症预防快速上浮脱险所致减压病的发生。     

高压下快速上浮脱险不同退筒方法的比较与建议

目的通过比较快速上浮脱险退筒时不同的脱险筒卸压方法, 为提高紧急情况下的退筒安全性提供依据。方法模拟在30、60、120、150 m深度进行快速上浮脱险时发生紧急情况, 人员需要退筒, 脱险筒采用排水或排气等方法卸压, 分别记录脱险筒内压力值的变化情况。结果 2种方法的减压速率都出现先快后慢的情况, 且最大速率超过10 m/s。结论在脱险筒压力超过60 m时不宜采用上述二种方法直接卸压, 可在脱险筒直通大气出口处增加手动阀门, 以保证人员安全;在脱险筒压力低于60 m时, 建议采用排水的方法卸压。     

快速上浮脱险训练对艇员正负性情绪的影响

快速上浮脱险训练是艇员的必训科目之一，也是一种对艇员应激强度较大的训练。考察不同深度条件下以及不同神经特质的艇员在正、负性情绪方面的变化趋势，有助于掌握参训艇员的心理状态变化规律，提高应激管理水平，为圆满完成训练任务提供有力保障。     

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.     

潜艇艇员10m深度模拟快速上浮脱险训练的医学保障体会

快速上浮脱险法是在自由上浮脱险法的基础上发展起来的。使用这一方法的前提是 :失事潜艇固壳完好 ,舱室未形成高压。实施时 ,脱险人员须穿戴特殊脱险抗浸服 ,经特设的调压舱快速调压后 ,快速上升出水 ,不需在水中停留减压。快速上浮脱险技术自 196 2年英国首次采用以来 ,目前已在许多国家推广。我国从 80年代开始了这方面的研究工作。随着潜艇艇员快速上浮脱险技术的研究日趋深入 ,这一技术必将在单人脱险方面发挥更大的作用。2 0 0 1年 ,我们完成了一次对模拟快速上浮的潜艇艇员和救护潜水员实施医学保障的任务 ,现报告如下。一、训练条件…     

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150 m不安全快速上浮脱险致减压病大鼠肺组织白细胞介素-10和白细胞介素-13表达的变化

目的 研究模拟150 m不安全快速上浮脱险致减压病(decompression sickness,DCS)大鼠肺组织抗炎因子白细胞介素(interleukin,IL)-10、IL-13表达的变化规律.方法 模拟150 m不安全快速上浮脱险处理后0.5、3、6、12、24 h对大鼠肺组织IL-10、IL-13 mRNA表达水平及蛋白分子含量变化进行检测,并与常压空气对照组对比.结果 与对照组比较,模拟150m不安全快速上浮脱致DCS大鼠肺组织IL-10 mRNA水平在0.5h显著升高(2.104 4±0.361 5,P=0.026);IL-13 mRNA表达在0.5h(15.030 2±2.371 5,P=0.014)和3 h(2.459 8±0.419 1,P=0.018)显著增高.肺组织IL-10含量虽然在0.5h与常压空气对照组相比差异无统计学意义(P＞0.05),但其他各时间点均出现了不同程度的升高,且差异均有统计学意义(P=0.000);IL-13含量在0.5h和3h先降低,在6h和12 h再恢复接近正常水平,24h又降低,3h(P=0.028)、24 h(P =0.008)与常压空气对照组比较差异有统计学意义,6 h(P=0.041)、12 h(P =0.025)与24 h比较差异也具有统计学意义.结论 模拟150 m不安全快速上浮脱险致DCS大鼠肺损伤后,24 h内可导致肺组织IL-10 mRNA水平和IL-10、IL-13含量发生显著改变,具体机制有待进一步研究.     

19F-MRI of perflubron for measurement of oxygen partial pressure in porcine lungs during partial liquid ventilation.

A method for in vivo measurement of oxygen partial pressure (pO2) in porcine lungs during partial liquid ventilation (PLV) with perflubron (PFOB) was developed. A pulse sequence for high-resolution MRI of the distribution of PFOB in the lung after intratracheal administration was developed as well. Moreover, quantitative measurements of longitudinal relaxation time T(1) of (19)F resonances for assessment of regional pO2 are described. Due to the need to acquire data during a single expiratory breathhold, only low SNRs were achieved in vivo. Therefore, simulations were performed to investigate the influence of background noise on T(1) values calculated from data with low SNR. Based on these simulations, a postprocessing strategy was developed to correct for systematic errors by background noise prior to quantitative analysis. Results of a pilot study in pigs under conditions of PLV are presented.     

The effects of increased forward trunk lean during stair ascent on hip adduction and internal rotation in asymptomatic females

BackgroundIncreased hip adduction and internal rotation can lead to excessive patellofemoral joint stress and contribute to patellofemoral pain development. The gluteus maximus acts as a hip extensor, abductor, and external rotator. Improving hip extensor use by increasing one’s forward trunk lean in the sagittal plane may improve frontal and transverse plane hip kinematics during stair ascent.Research questionDoes increasing forward trunk lean during stair ascent affect peak hip adduction and internal rotation?MethodsTwenty asymptomatic females performed five stair ascent trials (96 steps/min) on an instrumented stair using their self-selected and forward trunk lean postures. Three-dimensional kinematics (200 Hz) and kinetics (2000 Hz) were recorded during the stance phase of stair ascent. Biomechanical dependent variables were calculated during the stance phase of stair ascent and included peak forward trunk lean, hip flexion, hip adduction, hip internal rotation angles, and the average hip extensor moment.ResultsDuring the forward trunk lean condition, decreases were observed for peak hip adduction (MD = 2.8˚; 95% CI = 1.9, 3.8; p < 0.001) and peak hip internal rotation (MD = 1.1˚; 95% CI = 0.1, 2.2; p = 0.04). In contrast, increases were observed during the forward trunk lean condition for the peak forward trunk lean angle (MD = −34.7˚; 95% CI = −39.1, −30.3; p < 0.001), average hip extensor moment (MD = −0.5 N·m/kg; 95% CI = −0.5, −0.4; p < 0.001), and stance time duration (MD = −0.02 s; 95% CI = −0.04, 0.00; p = 0.017).SignificanceIncreasing forward trunk lean and hip extensor use during stair ascent decreased peak hip adduction and internal rotation in asymptomatic females. Future studies should examine the effects of increasing forward trunk lean on hip kinematics, self-reported pain, and function in individuals with patellofemoral pain.     

The influence of sagittal trunk posture on the magnitude and rate of patellofemoral joint stress during stair ascent in asymptomatic females

Background: Excessive patellofemoral joint stress (PFJS) is thought to be a contributory factor to patellofemoral pain (PFP). Thus, treatment strategies that minimize PFJS rate and magnitude during painful activities like stair ascent may be useful for optimizing outcomes for PFP patients. Sagittal plane trunk posture has been shown to influence PFJS during running although it is unknown if a similar relationship exists during stair ascent. Research Question: Does altering sagittal plane trunk posture affect PFJS rate and/or magnitude during stair ascent? Methods: Twenty asymptomatic females (23.4±2.5 yr; height: 164.4±7.9 cm; mass: 63.0±12.2 kg) performed 5 stair ascent trials (96 steps/min) during 3 conditions: self-selected trunk (SS), flexed trunk (FLX), and extended trunk (EXT). Three-dimensional kinematics (200 Hz) and ground reaction forces (2000 Hz) were collected during each trial. A previously described mathematical model was used to calculate PFJS that included subject-specific and non-subject-specific model inputs. Dependent variables included sagittal plane trunk angle, and the rates and magnitudes of PFJS, patellofemoral joint reaction force (PFJRF), and PFJ contact area during the stance phase of stair ascent. Results: Compared to SS, peak PFJS decreased during FLX (mean difference (MD)=2.6 MPa; p<0.001; 95%CI=2.2 to 2.9; effect size (ES)=5.2) and increased during EXT (MD=-3.3 MPa; p<0.001; 95%CI=-3.9 to -2.6; ES=-3.4). Similarly, PFJS rate decreased during FLX (MD=17.8 MPa/sec; p<0.001; 95%CI=13.6 to 21.9; ES=3.6) and increased during EXT (MD=-14 MPa/sec; 95%CI=-19.4 to -8.7; p<0.001; ES=-2.2). Significance: Sagittal plane trunk posture influences PFJS rate and magnitude during stair ascent in asymptomatic females. Increasing and decreasing forward trunk flexion resulted in decreased and increased PFJS respectively. Future studies should examine the effects of these movement strategy modifications on pain and function in patients with PFP.     

The biomechanical functional demand placed on knee and hip muscles of older adults during stair ascent and descent

Age-related decline in physical capabilities may lead to older adults experiencing difficulty in performing everyday activities due to high demands placed on the muscles of their lower extremity. This study aimed to determine the biomechanical functional demand in terms of joint moments and maximal muscle capabilities at the knee and hip joints while older adults performed stair ascent (SA) and stair descent (SD). Eighty-four healthy older adults aged 60-88 years were tested. A torque dynamometer attached to a purpose-built plinth was utilized to measure muscle moments at the knee and hip joints. Participants also underwent full body 3-D biomechanical assessment of stair ascent and descent using an 8-camera VICON system (120 Hz) with 3 Kistler force plates. Stair negotiation required knee extensor moments in excess of the maximum isometric muscle strength available (SA 103%, SD 120%). For the hip, the levels of demand were high, but were slightly lower than those of the knee joint. Stair negotiation placed a high level of demand on the knee extensors with demand in SA reaching maximal isometric capacity and demand in SD exceeding maximal isometric capacity. The levels of demand leave little reserve capacity for the older adult to draw on in unexpected situations or circumstances.