氢氧化锂吸收剂用于清除闭式/半闭式潜水呼吸器二氧化碳的实验研究

Objective To investigate the applicability of lithium hydroxide ( LiOH) absorbent in closed/semi-closed diving apparatus. Methods One LiOH absorbent and 2 classical sodium lime absorbents ( sodium lime 1 and sodium lime 2) were chosen to carry out unmanned experiments by using the manual lung and a closed breathing apparatus. Temperature in the canister and CO2 level at the outlet of the canister were timely monitored and recorded. When CO2 level in the inhaled gas exceeded 1.5%, the experiment was terminated, and the time when CO2 levels reached at 0. 5% and 1. 5% was recorded. The amounts of absorbents filled, temperatures and the time when CO2 levels reached at 0. 5% and 1.5% were recorded. Results The weight of the LiOH absorbent was minimal (1113. 5 g), which was obviously less than the classical absorbent, sodium lime 1 and sodium lime 2( 1845.0 g and 1855.5 g),which was a disadvantage to the positive buoyancy of the diving apparatus. With the LiOH absorbent, the time for CO2 to reach 0.5% (T0.5) and 1.5% (T1.5) was 86.00 ± 1. 63 min and 119. 00 ± 2. 94 min respectively. While for sodium lime 1, the time for T0.5 and T1.5 were 55. 00 ±0. 82min and 62. 00 ± 1. 63min and for sodium lime 2, the time for T0.5 and T1.5 were 57. 00 ± 2.45min and 65. 00 ± 1. 63min respectively. The T1.5 and T1.5 of the LiOH absorber were obviously longer than those of sodium lime 1 and sodium lime 2 (P＜0. 05). The maximum temperature in the LiOH canister was 191. 5℃,which was 2. 56 times greater than that of sodium lime 1 (74. 8℃) ,and 2. 29 times greater than that of sodium lime 2 (83. 6 ℃ ). Conclusions This kind of LiOH absorber might not be suitable to closed/semi-closed diving apparatus.     

一种新型多孔LiOH型二氧化碳吸收剂性能研究

目的研究多孔Li OH型CO2吸收剂的密度和粘结剂H含量对其抗压强度及CO2吸收性能的影响,为新型多孔Li OH型CO2吸收剂的设计提供依据。方法通过改变吸收剂的成型压力及调整配方中粘结剂H含量,压制出不同密度及粘结剂H含量的CO2吸收剂,然后测试吸收剂的抗压强度和对CO2吸收性能。结果密度为0.73 g/cm3的CO2吸收剂的抗压强较密度为0.67 g/cm3和0.70 g/cm3的均有较大幅度的增长;吸收剂中粘结剂H含量增加时,抗压强度先增大后减小,当粘结剂H含量达到4%时,抗压强度达到最大值;CO2吸收剂密度增加,相同吸收时间测得的CO2的分压增大;粘结剂H含量变化时,相同吸收时间测得的CO2分压相当。结论吸收剂的密度增加,其抗压强度明显提高,但对CO2的吸收效率下降;粘结剂H含量变化对CO2的吸收性能影响不大;吸收剂中粘结剂H的最佳含量为4%。     

休闲自给式水下呼吸器潜水后飞行途中发生Ⅱ型减压病一例CSCD

自给式水下呼吸器（self-containedunderwaterbreathingapparatus,SCUBA）潜水又称水肺潜水,指潜水员自行携带水下呼吸系统所进行的潜水活动,休闲SCUBA潜水多数采用开放式呼吸系统,潜水深度限于40m以浅。国内有关休闲SCUBA潜水导致减压病的研究或报告较少,潜水者及医院高压氧科医护人员对休闲SCUBA潜水减压病的认识存在不足。我院于2015年8月30日收治休闲SCUBA潜水Ⅱ型减压病一例,使用0．12MPa（1．2ATA）吸氧方案加压治疗,现报道如下。     

模拟480m氦氧饱和-493m巡回潜水实验研究的设备保障

目的 保障模拟480 m氦氧饱和-493 m巡回潜水实验的顺利进行,检验饱和潜水设备保障方案.方法 4名潜水员利用500 m饱和潜水系统和KMB18(B)潜水装具,在实验室进行模拟大深度饱和-巡回潜水.实验前通过维修、调试设备,使其处于备便状态.实验中按照设备保障方案,控制舱内环境压力、氧(O2)分压、二氧化碳( CO2)分压及温湿度参数,保障潜水员完成水下巡潜作业及日常饮食起居,确保潜水员按时、顺利、安全出舱.结果 经过82 h加压后,达到的饱和深度为480 m,4名潜水员在此深度下停留49.6h,达到巡潜最大深度493m;减压时间约302.4 h,高压暴露总时间为434 h.加压过程和饱和逗留期间维持O2分压35 ～45 kPa,减压时维持O2分压48～52 kPa,减压至12 m后,维持O2浓度21％ ～23％;CO2分压一般限制在0.5 kPa以内.相对湿度60％～80％;居住舱内温度29～32℃.结论 潜水员出舱后身体状况良好,感觉舱内环境控制比较舒适,设备保障结果与预想方案吻合,设备保障方案成功.     

二氧化碳用于多层螺旋CT诊断肺栓塞的初步实验研究

目的探讨二氧化碳(CO2)作为阴性对比剂在多层螺旋CT(MSCT)诊断肺栓塞(PE)中的可行性。材料与方法6只用明胶海绵建立了PE模型后的犬分别用CO2作为阴性对比剂、碘对比剂作为阳性对比剂行MSCT血管造影检查,对所得两组图像进行比较。结果60ml CO2可使肺动脉充分显影,CO2 CT血管成像和碘对比剂CT血管成像都显示了肺动脉内的栓子,栓子在前者图像上比后者更清晰。结论用CO2作为阴性对比剂行MSCT扫描对诊断PE是可行的。     

模拟氦氧饱和潜水实验中监测潜水员尿量及尿电解质的作用

目的 探讨模拟2.6 MPa氦氧饱和潜水暴露时潜水员尿量及尿电解质变化对潜水员健康干预的监护作用.方法 7名健康男性潜水员参加模拟250 m氦氧饱和潜水,在暴露前、中、后每日取晨尿和24h尿检测尿常规、尿量、尿电解质、肌酐及N-乙酰-β-D-氨基葡萄糖苷酶(NAG)排泄量.结果参试潜水员尿常规在高压暴露过程中没有明显变化;尿量在暴露于2.0 MPa以上压力时略有增高,但无统计学意义(P＞0.05):尿Na+、K+、Cl-、Ca2+、Mg2+、NAG酶在高压下排泄减少(P＜0.05),尤以钙减少明显且持续时间长,但在减压后1周基本恢复至正常水平.结论 模拟2.6 MPa氦氧饱和潜水暴露过程中潜水员尿量和尿电解质排泄存在波动,检测尿量和尿电解质排泄量可为舱内潜水员的健康干预提供参考依据.     

中美联合25m氮氧饱和─80m氦氮氧巡回潜水实验的医学保障

中美联合２５ｍ氮氧饱和－８０ｍ氦氮氧巡回潜水实验的医学保障袁洪昌，荆岩林，周述尧，曲青林关键词潜水，氮氧饱和，巡回潜水，氦氮氧，减压，医学保障ＴｈｅｍｅｄｉｃａｌｓｕｐｐｏｒｔｏｆｔｈｅＣｈｉｎａ－ＵＳＡｊｏｉｎｔＣｈｉｓａｔ－Ⅱｓｉｍｕｌａｔｅｄ２...     

模拟潜水实验对豚鼠畸变产物耳声发射的影响(论著)

目的：观察豚鼠模拟潜水60m减压后对畸变产物耳声发射（distortionproductotoacousticemisssions，DPOAE）、皮层诱发电位及中耳形态学的影响。方法；杂色健康豚鼠8只，于加压前及减压后进行DPOAE和皮层诱发电位测试，并作颞骨切片光镜观察。结果；正常豚鼠潜水减压后DPOAE幅值强度及皮层诱发电位阈值均有不同程度的降低，与进舱前比有显著及非常显著性差异；而中耳形态学变化大者，其DPOAE值下降亦较明显。结论：在本实验条件下，豚鼠的鼓膜及中耳的阻抗发生变化，以致DPOAE值下降和皮层诱发电位阈值升高，并与中耳形态学的改变有相关性，说明中耳质量（mass）及劲度声抗（stiffnessimpedance）的改变可以影响DPOAE福值，因而表明DPOAE可对中耳功能进行评估。     

350m模拟氦氧饱和潜水中人体生理功能变化的研究

本研究的目的在于了解人体在大深度高气压条件下长期生活工作时的生理功能变化规律、作业和适应能力。在３５０ｍ模拟氦氧饱和潜水的不同阶段监测了潜水员的中枢神经－心理运动、肺通气、心血管、免疫、消化等功能的一系列医学－生理学指标，获得的资料为今后海上大深度饱和潜水实际应用提供了科学依据。     

豚鼠模拟潜水实验的畸变产物耳声发射及内耳肌动蛋白免疫组化反应观察(论著)

目的：为了解模拟潜水对豚鼠畸变产物耳声发射（ＤＰＯＡＥ）及内耳肌动蛋白的影响。方法：选用健康、耳廓反射正常杂色豚鼠１２只，潜水深度为６０米（０．６ＭＰａ表压），于潜水前、后测试畸变产物耳声发射，并用免疫组化方法观察耳蜗及前庭的肌动蛋白的改变。结果：豚鼠模拟潜水后ＤＰＯＡＥ幅值与潜水前比均有显著下降。耳蜗内及前庭壶腹嵴肌动蛋白免疫组化反应结果与对照组比无变化。结论：豚鼠在潜水过程中，ＤＰＯＡＥ幅值下降是由于加压使中耳受气压损伤所致，而耳蜗及前庭肌动蛋白的免疫组化反应结果潜水前后无改变，说明本模拟潜水加－减压方案对内耳无损伤。     

腹内脏器细针穿刺行CO2静脉造影的实验研究

目的探讨细针穿刺腹部脏器组织行CO2静脉造影的可行性和安全性。方法选择健康雌猪2头和雌犬2条，麻醉后，用25G细穿刺针直视下多点穿刺脾、肝、肾、胰腺、小肠和子宫组织。手推法注射CO2行数字减影静脉造影。结果细针穿刺CO2造影可显示脾-门静脉系统、肝静脉、门静脉、肾一下腔静脉、子宫-卵巢静脉，不能显示胰腺和小肠引流静脉。其中，以脾-门静脉系统显示最佳，其影像质量评定结果为A级、B级和C级分别为87．5％(7／8)、12．5％(1／8)和0％；其他依次为肝静脉[A级、B级和C级分别为81．8％(9／11)、18．2％(2／11)和0％]、门静脉[A级、B级和C级分别为77．8％(7／9)、22．2％(2／9)和0％]、肾-下腔静脉[A级、B级和C级分别为38．5％(5／13)、61．5％(8／13)和0％]、子宫．卵巢静脉[A级、B级和C级分别为0％、33．3％(2／6)和66．7％(4／6)]。术中未发现实验动物的重要生命体征发生改变。结论细针直接穿刺部分腹部脏器组织行CO2数字减影静脉造影是安全可行的。     

二氧化碳激发试验评估脑血管储备功能的临床研究

目的:应用5％ CO2作为血管扩张介质,通过CT灌注成像(CTPI)及CT血管成像(CTA)分析基础状态和激发状态下正常受试者脑血流动力学及脑血管储备功能变化特点和临床意义.方法:对30名排除肺部和心脏疾病的正常受试者行基础态CTPI和CTA检查,吸入5％CO2和95％ O2混合气体2 min后行CTPI检查.结果:C...     

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.     

Feasibility of using automated insufflated carbon dioxide (CO2) for luminal distension in 3.0T MR colonography

Purpose

Primary aim of our study was to prospectively evaluate the feasibility of automated carbon dioxide (CO₂) delivery as luminal distending agent in 3.0 T MR colonography.

Materials and methods

Rectally insufflated CO₂ was evaluated in four groups with different bowel preparation (A–D). Bowel preparation regimes were: gadolinium-based tagging (A), bowel purgation (B), barium-based tagging (C) and iodine-based tagging (D). Supine (3D)T1w-FFE and (2D)T2w-SSFSE series were acquired. Each colon was divided into six segments (cecum S1–rectum S6). Two observers independently assessed the presence of artefacts, diagnostic confidence and segmental colonic distension. Also characteristics of the residual stool (presence, composition and signal-intensity) were assessed per segment. Discomfort was assessed with questionnaires.

Results

Fourteen healthy subjects were included. Colonic distension by means of rectally insufflated CO₂ was not associated with susceptibility artefacts. Overall image quality was affected by the presence of bowel motion-related artefacts: none of the segments in 3DT1w-series and 10/84 (12%) colon segments in 2DT2w-series were rated artefact-free by both observers. Diagnostic confidence ratings were superior for the 2DT2w-SSFSE series. Overall bowel distension was rated adequate to optimal in 312/336 (93%) colon segments.

Conclusion

MR colonography at 3.0 T using carbon dioxide (CO₂) for colonic distension is technically feasible. The presence of intraluminal CO₂ did not result in susceptibility artefacts, although overall image quality was influenced by artefacts.