何谓液体通气?有无临床应用前景?

液体通气 (ＬＶ)是近年来出现的一种新的通气方式 ,大量基础及临床研究表明 ,完全液体通气 (ＴＬＶ)及部分液体通气(ＰＬＶ)能有效改善急性肺损伤及急性呼吸窘迫综合征(ＡＲＤＳ)的气体交换、提高肺顺应性、减轻肺内病理损伤 ,ＰＬＶ有望成为治疗ＡＲＤＳ的有效手段。一、基本概念和工作方式ＬＶ包括ＴＬＶ和ＰＬＶ ,ＴＬＶ指用液态呼吸介质 (ＬＲＭ)完全替代气态介质 ,应用液体通气机进行人工通气的技术。 196 6年Ｃｌａｒｋ等[1] 将全氟碳化合物 (ＰＦＣ)应用于ＴＬＶ标志着现代ＬＶ研究的开始。ＴＬＶ工作方式是向肺内注入相当于肺总量的…     

ARDS时的潮气量测定及引起的高碳酸血症

ＡＲＤＳ时的潮气量测定及引起的高碳酸血症［英］／ＲｏｕｐｌｅＥ…ＡｍＪＲｅｓｐｉｒＣｒｉｔｃａｒｅＭｅｄ．－１９９５，１５２（１）．－１２１～１２８急性呼吸窘迫综合征（ＡＲＤＳ）时机械通气可促发肺过度充气而引起肺损伤，其呼吸系统静态压力－容量（Ｐ－Ｖ...     

高血压病患者动脉血管平滑肌细胞NO含量及作用

目的: 探讨在基础状态下高血压病患者（ＥＨ）动脉血管平滑肌细胞（ＶＳＭＣ）的一氧化氮合酶（ＮＯＳ）和一氧化氮（ＮＯ）的变化特点及其对ＶＳＭＣ增殖的影响。方法: 采用血压正常者（ＮＴ）及ＥＨ 患者的肠系膜动脉进行分离培养,对比观察ＮＴ组和ＥＨ 组的动脉ＶＳＭＣ的ＮＯＳ活性、ＮＯ含量、细胞计数和细胞周期的变化,研究ＥＨ 患者动脉ＶＳＭＣ的ＮＯＳ－ＮＯ系统的变化与细胞增殖的关系。结果:①在基础状态下,ＥＨ组动脉ＶＳＭＣ的ＮＯＳ活性和ＮＯ含量较ＮＴ组明显降低（Ｐ＜ ０．０５）。②ＥＨ组动脉ＶＳＭＣ的细胞数量明显高于ＮＴ组（Ｐ＜ ０．０５）。③ＥＨ组Ｓ期百分率和细胞增殖指数（ＰＩ）明显高于ＮＴ组（Ｐ＜ ０．０５）,ＥＨ组Ｇ０／Ｇ１ 期百分率较ＮＴ组明显降低（Ｐ＜ ０．０５）。④ＮＴ组和ＥＨ组的ＮＯＳ活性和ＮＯ含量与ＰＩ均呈负相关。结论:ＥＨ患者动脉ＶＳＭＣ存在着ＮＯＳ－ＮＯ系统功能低下;ＮＯ具有抑制ＶＳＭＣ增殖的作用     

急性心肌梗塞患者体内维生素E与脂质过氧化的关系

检测１２例急性心肌梗塞（ＡＭＩ）、２１例冠心病（ＣＡＤ）和２０例正常对照（ＮＳ）的血清维生素Ｅ（ＶｉｔＥ）、人超氧化物岐化酶（ｈＳＯＤ－１）及血浆过氧化脂质（ＬＰＯ）的代谢产物之一丙二醛（ＭＤＡ）水平。结果显示ＡＭＩ组的ＭＤＡ水平明显高于ＣＡＤ及ＮＳ组，而ＶｉｔＥ水平则显著低于ＣＡＤ及ＮＳ组，二者呈显著负相关（γ＝－０．６７，Ｐ＜０．００１）；ＡＭＩ和ＣＡＤ组的ｈＳＯＤ－１水平均明显低于ＮＳ组，但其两组间无差异，提示ＡＭＩ时ＶｉｔＥ作为主要的抗氧化剂被大量消耗，可能是ＡＭＩ发展的原因之一。     

国产替尼泊苷（VM26）治疗肺癌临床验证研究

评估国产ＶＭ２６治疗３７例肺癌,其中ＳＣＬＣ３３例,ＮＳＣＬＣ４例。男性３１例,女性６例。年龄范围３６－７３岁,中位年龄５４．５岁。初治３０例。复治７例ＫＰＳ≥６０分３４例,〈６０分３例。方法分４组,国产ＶＭ２６单药组１０例,国产ＶＭ２６＋ＩＣＢＰ组１２例,进口ＶＭ２６＋ＣＢＰ组（对照组）１１例,国产ＶＭ２６＋ＢＣＮＵ＋ＤＤＰ组４例,均经２－３周期治疗。结果 疗效ＳＣＬＣ国产ＶＭ２６单药有效率达４     

通气机导致急性肺损伤的机制及呼气末正压的保护作用研究

呼气末正压（ＰＥＥＰ）这一简单实用的机械通气手段在通气机导致的急性肺损伤（ｖｅｎｔｉｌａｔｏｒｉｎｄｕｃｅｄａｃｕｔｅｌｕｎｇｉｎｊｕｒｙ，ＶＩＡＬＩ）的预防中具有重要意义［１］。我们拟从细胞免疫、氧化损伤及组织细胞学角度探讨ＶＩＡＬＩ的发生机理及ＰＥＥＰ对ＶＩＡＬＩ的保护作用。材料和方法　健康雄性ＳＤ大鼠３０只，体重２５０ｇ～４００ｇ，平均３６０ｇ，随机分为３组，Ａ组为对照组，给常规机械通气；Ｂ组为大潮气量组，给大潮气量机械通气；Ｃ组为ＰＥＥＰ保护组，给大潮气量加ＰＥＥＰ通气。将大鼠麻醉后，行…     

硒锰锌维生素E与心肌损伤关系的实验研究

用低Ｓｅ高Ｍｎ人工半合成饲料喂饲大白鼠，复制动物心肌损伤模型。补加Ｓｅ（０．３ｍｇ／ｋｇ）、Ｚｎ（２００ｍｇ／ｋｇ）、ＶＥ（２００ＩＵ／ｋｇ）．以观察单纯补加Ｓｅ、Ｚｎ、ＶＥ或三者不同组合对心肌损伤的影响。实验结果表明，单纯补加因素中，补加ＶＥ组大鼠的心肌坏死检出率与低Ｓｅ高Ｍｎ组比下降（Ｐ＜０．０５），坏死面积也缩小，心肌ＳＤＨ和ＣＣＯ活性提高。补加二因素组中．补加Ｓｅ＋Ｚｎ和Ｓｅ＋ＶＥ组大鼠心肌坏死检出率下降（Ｐ＜０．０５），而补加Ｓｅ十ＶＥ组下降更明显，心肌ＳＤＨ和ＣＣＯ活性提高更明显。补加Ｓｅ＋Ｚｎ＋ＶＥ组大鼠心肌坏死检出率进一步降低（Ｐ＜０．０５），坏死面积也最小，心肌ＣＣＯ活性明显提高．ＳＤＨ活性改变不明显。     

老年矽肺与一氧化氮及氧化和抗氧化的关系

目的探讨老年矽肺与一氧化氮（ＮＯ）及氧化和抗氧化的关系。方法检测８５例矽肺患者和８０例对照者的血浆一氧化氮（ＰＮＯ）、维生素Ｃ（ＰＶＣ）、维生素Ｅ（ＰＶＥ）、β胡萝卜素（ＰβＣＡＲ）及红细胞超氧化物歧化酶（ＥＳＯＤ）、过氧化氢酶（ＥＣＡＴ）、谷胱甘肽过氧化物酶（ＥＧＳＨＰＸ）值。结果与对照组比较,患者组ＰＶＣ、ＰＶＥ、ＰβＣＡＲ、ＥＳＯＤ、ＥＣＡＴ、ＥＧＳＨＰＸ均值显著降低、ＰＮＯ均值显著升高（Ｐ＜００１）;直线回归和相关分析表明上述各检测值与患者病程均有相关,逐步回归表明患者病情、肺功能状态与ＰＮＯ、ＰＶＥ、ＥＳＯＤ值相关最密切。结论老年矽肺患者ＮＯ代谢异常,氧化抗氧化平衡严重失调。     

高血压病患者动脉平滑肌细胞NO的变化及其与发病的关系

为探讨高血压病（ＥＨ）患者一氧化氮（ＮＯ）浓度变化特点与高血压病发病的特点，本研究以复合胶元酶法分离培养ＥＨ患者和血压正常者（ＮＴ）离体动脉平滑肌细胞（ＶＳＭＣ）检测细胞培养液的ＮＯ含量和ＶＳＭＣ的一氧化氮含量（ＮＯＳ）的活性，观察ＥＨ患者动脉ＶＳＭＣ分泌ＮＯ的特点，结果显示：（１）ＥＨ组ＶＳＭＣ的ＮＯ含量和ＮＯＳ活性均显著于低于ＮＴ组（Ｐ〈０．０１）；（２）ＥＨ患者和ＮＴＶＳＭＣ的ＮＯ含量和ＮＳ     

系统性红斑狼疮并发无菌性骨坏死的危险因素分析

目的　探讨系统性红斑狼疮（ Ｓ Ｌ Ｅ） 无菌性骨坏死（ Ａ Ｖ Ｎ） 与临床和实验室检查的关系。方法　统计本院发生无菌性骨坏死住院的２９ 例 Ｓ Ｌ Ｅ 病人,同时随机抽样不伴有无菌性骨坏死的４０ 例 Ｓ Ｌ Ｅ 和２０ 例皮肌炎／ 多发性肌炎（ Ｄ Ｍ／ Ｐ Ｍ） 病人作为对照组。分析性别、年龄、贫血、高血压、雷诺现象、血管炎、肾脏受累、抗磷脂抗体、柯兴征以及糖皮质激素用量和免疫抑制剂的应用与 Ａ Ｖ Ｎ 发生的关系。结果　 Ｓ Ｌ Ｅ＋ Ａ Ｖ Ｎ 组的糖皮质激素治疗起始量１ 、３ 、４ ～６ 、７ ～１２ 个月的剂量较 Ｓ Ｌ Ｅ 对照组大（ Ｐ＜ ００５ ～００１） ,而１３ ～２４ 个月期间两组糖皮质激素的用量无统计学差异;与不伴 Ａ Ｖ Ｎ 的 Ｄ Ｍ／ Ｐ Ｍ 组比较,上述各时期糖皮质激素用量均无差异。还发现, Ａ Ｖ Ｎ 的发生与年龄小、血管炎和较少应用免疫抑制剂相关。结论　糖皮质激素是 Ｓ Ｌ Ｅ 病人发生无菌性骨坏死的重要因素,但不是唯一因素。     

肺泡复张后不同呼气末正压和潮气量调节策略对防止肺泡再萎陷效果的实验研究

目的探讨肺泡复张(RM)后再萎陷的机制以及呼气末正压(PEEP)和潮气量(VT)的调节策略。方法健康杂种犬18只,建立油酸所致急性呼吸窘迫综合征(ARDS),行容量控制通气(VCV)、PEEP 16 cm H2O、VT10 m l/kg、通气频率(RR)30次/m in,稳定后作为基础状态(0 m in)。以压力控制通气[气道峰压(PIP)50 cm H2O,PEEP 35 cm H2O,持续60 s]行RM,然后随机分为小VT中等PEEP组(LVMP组,VT10 m l/kg、PEEP 16 cm H2O、RR 30次/m in),小VT低PEEP组(LVLP组,VT10 m l/kg、PEEP 10 cm H2O、RR 30次/m in)和中等VT低PEEP组(MVLP组,VT15 m l/kg、PEEP 10cm H2O、RR 20次/m in)。观察4 h后处死动物,行支气管肺泡灌冼。监测氧合、呼吸力学、血流动力学及肺损伤指标。结果(1)LVMP、LVLP、MVLP组低位拐点(LIP)分别为(16.0±1.3)、(15.8±3.0)、(16.3±1.9)cm H2O。(2)在RM后30、60 m in,LVMP组动脉血氧分压(PaO2)[(371±64)、(365±51)mm Hg]显著高于LVLP组[(243±112)、(240±108)mm Hg]及MVLP组[(242±97)、(232±87)mm Hg,P均<0.05],但直至RM后4 h 3组比较差异无统计学意义;LVLP与MVLP组在RM后各个时间点的PaO2与基础状态比较差异均无统计学意义;MVLP组的通气功能较其他两组显著改善。(3)与基础状态比较,RM后LVMP组平均动脉压(mABP)显著降低,平均肺动脉压(mPAP)显著增加,而其他两组mABP保持稳定,mPAP降低。(4)与基础状态比较,3组PIP和气道平台压(Pp lat)在RM后均显著降低,呼吸系统静态顺应性(Cst)显著改善。在RM后同一时间点比较,MVLP组PIP、Pp lat和Cst均显著好于LVMP组。MVLP组与LVLP组相比,Cst有增加趋势。(5)在相同部位的支气管肺泡灌冼液中,肺损伤指标在各组之间无显著差异。结论与LIP相近的高PEEP有助于防止复张肺泡的再萎陷,但对血流动力学和呼吸力学产生不利影响;早期应用RM能有效“节约”PEEP,并为上调VT提供了较肺泡复张之前更大的空间。     

容许性高碳酸血症对急性肺损伤动物心肺影响的观察

观察不同水平的容许性高碳酸血症对油酸型急性肺损伤模型的心肺功能影响。复制猪ＡＬＩ模型，四腔热稀释漂浮导管监测血液动力学不同潮气量致不同程度的ＰＨＣ。     

侧卧位和分侧肺通气对单侧急性肺损伤犬的影响

目的观察体位和分侧肺通气对单侧急性肺损伤(ALI)犬的影响,探讨单侧ALI时合理的机械通气方式。方法健康杂种犬28只,建立盐酸所致单侧ALI,行容量控制通气(VCV),分为常规通气组(A组)、常规通气+健侧卧位组(B组)、不同步分侧肺通气组(C组)、同步分侧肺通气组(D组)。通气240min后,每组随机选取4只犬行核素显像。监测氧合、血流动力学、呼吸力学和肺损伤指标。结果(1)通气30min后B、C、D组氧合指数(PaO2/FiO2)[(277±23)、(296±31)、(299±22)mmHg,1mmHg=0.133kPa]显著高于A组[(180±25)mmHg,P均<0.01],通气60min后C、D组PaO2/FiO2[(348±34)、(343±29)mmHg]显著高于B组[(314±33)mmHg,P均<0.05]。(2)通气120min后B组静态肺顺应性(Cst)[(23±4)ml/cmH2O]较A组[(19±2)ml/cmH2O]显著改善,通气60min后C、D组左侧Cst[(11±1)、(11±1)ml/cmH2O]均较ALI状态时显著改善[(7±2)、(6±1)ml/cmH2O,P均<0.01]。(3)B、C、D组损伤侧血流/总血流(Q损伤/Q总)[(31.3±4.6)%和(27.5±1.3)%、(27.3±2.8)%]与A组比较差异均有统计学意义[(38.3±2.2)%,P均<0.01]。结论健侧卧位和分侧肺通气均能明显改善单侧ALI犬的氧合和肺的顺应性,分侧肺通气改善氧合较健侧卧位更有效,改善氧合的机制可能与影响双侧血流分布有关。     

Effect of tidal volume and positive end-expiratory pressure on compliance during mechanical ventilation.

In 12 patients requiring therapy with mechanical ventilation for acute respiratory failure, total static compliance (Cst) increased from 29 +/- 4 ml/cm H2O at a tidal volume (TV) of 5 ml/kg to 42 +/- 7 ml/cm H2O at a TV of 15 ml/kg. Similarly, Cst increased from 42 +/- 7 ml/cm H2O to 52 +/- 8 ml/cm H2O between 0 and 6 cm H2O of positive end-expiratory pressure (PEEP). At high levels of pulmonary inflation (ie, high PEEP and large TV) compliance decreased. The changes of total respiratory compliance with TV were mainly due to changes in pulmonary compliance. With PEEP, the functional residual capacity increased, and specific compliance did not change. Two mechanisms may be responsible for the changes in compliance. First, varying TV or PEEP will alter the position of tidal ventilation on the pressure-volume curve, resulting in an increase in compliance with increasing TV and PEEP up to a point, where overdistention occurs and compliance decreases. Secondly, the function of the surface-lowering substance may be altered in acute pulmonary parenchymal disease, thus disturbing the regulation of surface tension over the range of pulmonary inflation studied.     

Persistent improvement of gas exchange and lung mechanics by aerosolized perfluorocarbon.

The effect of aerosolized perfluorocarbon (PFC) (FC77) on pulmonary gas exchange and lung mechanics was studied in a surfactant depleted piglet model. Sixty minutes after induction of lung injury by bronchoalveolar lavage, 20 piglets were randomized to receive aerosolized PFC (Aerosol-PFC, 10 ml/kg/h, n = 5), partial liquid ventilation (PLV) at FRC capacity volume (FRC-PLV, 30 ml/kg, n = 5) or low volume (LV-PLV, 10 ml/kg/h, n = 5), or intermittent mandatory ventilation (IMV) (Control, n = 5). After 2 h, perfluorocarbon application was stopped and IMV was continued for 6 h. Sixty minutes after the onset of therapy, PaO2 was significantly higher and PaCO2 was significantly lower in the Aerosol-PFC and the FRC-PLV groups than in the LV-PLV and the Control groups; p < 0.001. Six hours after treatment, maximum PaO2 was found in the Aerosol-PFC group: 406.4 +/- 26.9 mm Hg, FRC-PLV: 217.3 +/- 50.5 mm Hg, LV-PLV: 96.3 +/- 18.9 mm Hg, Control: 67.6 +/- 8.4 mm Hg; p < 0.001. PaCO2 was lowest in the Aerosol-PFC group: 24.2 +/- 1.7 mm Hg, FRC-PLV: 35.9 +/- 2.8 mm Hg, LV-PLV: 56.7 +/- 12.4 mm Hg, Control: 60.6 +/- 5.1 mm Hg; p < 0.01. Dynamic compliance (C20/c) was highest in the Aerosol-PFC group; p < 0.01. Aerosolized perfluorocarbon improved pulmonary gas exchange and lung mechanics as effectively as PLV did in surfactant-depleted piglets, and the improvement was sustained longer.     

Effect of Ventilation Mode on Gas Exchange during Partial Liquid Ventilation at Different Perfluorocarbon Doses in Surfactant-Depleted Lung

Although gas ventilation is an integral part of partial liquid ventilation (PLV), the role of ventilation mode during PLV is not established, especially at a varying perfluorocarbon dose. In 10 surfactant-depleted rabbits, PLV was performed at a low dose (10 ml/kg) and at a functional residual capacity (FRC) dose (30 ml/kg) of perfluorodecalin in pressure-control (PC) and volume-control (VC) modes in balanced sequence. In these four PLV trials, PC mode was adjusted to be identical to VC mode with regard to tidal volume and inspiratory-to-expiratory ratio. PaO2 during PLV in PC mode was higher than in VC mode at the Low dose (159 plus minus 93 mm Hg, 115 plus minus 75 mm Hg, respectively: p = 0.005) and at the FRC dose (228 +/- 114 mm Hg, 164 +/- 104 mm Hg, respectively: p = 0.002). PaCO2 during PLV in PC mode was lower than in VC mode at the Low dose (59 +/- 18 mm Hg, 72 +/- 20 mm Hg, respectively: p = 0.005), whereas PaCO2 at the FRC dose was not different between modes. Curves of inspiratory flow appeared least deformed with PLV in PC mode at the Low dose, whereas they were saw-tooth deformed with PLV in VC mode at both doses. Actual time for inspiratory gas flow during PLV was shorter in PC mode compared with VC mode at both doses. In conclusion, in surfactant-depleted rabbit, gas exchange during PLV was better with PC mode compared with VC mode, especially at a low perfluorocarbon dose. Given the same tidal volume, PC appeared to insufflate the perfluorocarbon-filled lung better than VC at both low and FRC doses of perfluorocarbon.     

体位改变对急性肺损伤兔肺功能与CT及病理的影响

目的　通过观察不同体位下急性肺损伤 (ALI)肺的氧合功能、呼吸力学、肺CT以及病理等的变化 ,来探讨不同体位的效应和可能机制。方法　采用油酸型ALI兔模型 ,分为正常对照组(Ⅰ组 )、仰卧位油酸组 (Ⅱ组 )、俯卧位油酸组 (Ⅲ组 )、旋转体位油酸组 (Ⅳ组 ) ,观察各组兔实验过程中动脉血氧分压 (PaO2 )、呼吸力学的变化。并进行肺CT扫描加以分析 ,最后作病理切片检查。结果Ⅲ、Ⅳ组的PaO2 [(15 8± 5 1)、(16 6± 37)mmHg]、肺的顺应性 [(2 8± 0 9)、(2 6± 0 7)ml/cmH2 O]显著高于Ⅱ组 [PaO2 (87± 2 4 )mmHg、肺的顺应性 (1 6± 0 5 )ml/cmH2 O ,P均 <0 0 5 ];Ⅲ、Ⅳ组肺内分流 [(2 1± 5 ) %、(18± 5 ) % ]显著低于Ⅱ组 [(2 9± 8) % ,P <0 0 5 ];Ⅳ组的气道峰压 [(2 0± 2 )cmH2 O]显著高于Ⅲ组 [(16± 2 )cmH2 O ,P <0 0 5 ];3个实验组的PaO2 与肺的顺应性呈显著正相关 ,与肺内分流呈显著负相关。ALI兔肺CT呈明显的重力依赖效应 ,体位的变化对肺CT的影响非常迅速。肺水肿在重力依赖区重 ,旋转后 ,重力依赖现象减轻。结论　俯卧位和旋转体位都能改善兔油酸型ALI肺的氧合 ;ALI肺出现重力压迫性肺不张 ,旋转体位能减轻肺不张的程度和使肺水肿趋于均匀。     

The effect of varying inspiratory to expiratory ratio on gas exchange in partial liquid ventilation.

BACKGROUND: In partial liquid ventilation (PLV), the nondependent lung was observed to be inflated first and the dependent lung later. The inflational time difference between the lung regions can lead to maldistribution of tidal gas and inefficient gas bubbling in the slow-inflating region during PLV. In this situation, increasing the inspiratory to expiratory (I:E) ratio of the mechanical ventilator would lessen the heterogeneity of regional ventilation and improve gas exchange possibly to a greater degree than in gas ventilation (GV). DESIGN AND SETTING: Animal study at the Asan Institute for Life Sciences, Seoul, Korea Subjects: Eighteen rabbits (2.6 +/- 0.5 kg) with acute lung injury by saline solution lavage. Interventions: Three I:E ratios were tried in GV and then in PLV. I:E ratios were changed by adjusting pause (1:2, 1:1, and 2:1; group 1) or by adjusting inspiratory flow rate (1:3, 1:1, and 2:1; group 2). MEASUREMENTS AND RESULTS: With increasing I:E ratio in all animals, PaO(2)/FIO(2) increased (80 +/- 24, 143 +/- 74, and 147 +/- 88 mm Hg; p = 0.001), and PaCO(2) decreased (74 +/- 15, 66 +/- 16, and 66 +/- 15 mm Hg; p = 0.006). The increases of PaO(2)/FIO(2) from 1:2/1:3 to 1:1 (p = 0.006) and from 1:1 to 2:1 (p = 0.036) were both greater in group 1 than in group 2. PaCO(2) decreased with increasing I:E ratio in group 1, but not in group 2. The change of PaO(2)/FIO(2) by varying the I:E ratio was 49 +/- 65% in PLV and 14 +/- 14% in GV (p = 0.003). CONCLUSIONS: Extending the I:E ratio, especially by adding pause, improved gas exchange in PLV. Oxygenation in PLV was affected by the I:E ratio to a greater degree than in GV.     

分侧肺通气时不同呼气末正压和潮气量对单侧肺损伤犬循环的影响

目的 观察不同步分侧肺通气和同步分侧肺通气对单侧急性肺损伤(ALI)犬循环的影响.方法 取健康杂种犬12只,建立盐酸所致单侧肺损伤动物模型,行容积控制通气,将犬按随机数字表法分为不同步分侧肺通气组(NS组)和同步分侧肺通气组(S组).参数:患侧潮气量3.5 ml/kg保持不变,呼气末正压(PEEP)选择15、20、25 cm H2O(1 cm H2O=0.098 kPa);患侧PEEP 10 cm H2O不变,潮气量用随机数字表法选择5、7.5、10 ml/kg.健侧通气参数始终不变,检测不同通气条件下两组犬血流动力学和氧动力学指标.结果 (1)患侧潮气量3.5 ml/kg不变,PEEP为15、20 cm H2O时,两组血流动力学和氧动力学参数差异无统计学意义.当患侧PEEP为25 cm H2O时,NS组心率、体循环平均压(mABP)、心输出量、氧合指数和混合静脉血氧饱和度(SvO2)分别为(98±8)次/min、(84±6)mm Hg(1 mm Hg=0.133 kPa)、(1.10±0.13)L/min、(199±14)mm Hg和(55±6)%,明显低于S组[分别为(124±9)次/min、(103±7)mm Hg、(1.52±0.28)L/min、(221±15)mm Hg和(62±4)%,t值分别为-7.852、-16.561、-15.043、-13.314和-5.653,均P＜0.01].(2)患侧PEEP 10 cm H2O不变,潮气量分别为5、7.5 ml/kg时,两组的血流动力学和氧动力学参数比较差异无统计学意义.当患侧潮气量为10 ml/kg时,NS组HR、mABP、心输出量、氧合指数和SvO2均低于S组(均P＜0.01).结论 在本实验动物模型中,患侧与健侧所用PEEP水平相差≤20 cm H2O或患侧潮气量≤7.5 ml/kg时,同步和非同步分侧肺通气均能保持循环稳定.若需要更高水平PEEP时,建议选用同步分侧肺通气.     

Tidal volume reduction in ARDS. Effect on cardiac output and arterial oxygenation

During continuous positive pressure ventilation (CPPV), mean airway pressure and lung volume will be influenced both by the tidal volume (VT) employed and the amount of positive end-expiratory pressure (PEEP). The effect of varying levels of CPPV on PaO2 and cardiac output (Q) has been previously assessed by adjusting the level of PEEP at constant VT. This study examined the influence of a 200-ml reduction in VT, at a constant PEEP of 15 cm H2O, on the PaO2 and Q of 21 patients with adult respiratory distress syndrome (ARDS). The relationship between change in Q and change in total respiratory system compliance (Cst) after VT reduction was also examined. VT reduction from 14.1 +/- 0.8 ml/kg to 11.2 +/- 0.9 ml/kg yielded an increase in Q (+ 15 +/- 12 percent, p less than 0.01) without a significant change in PaO2 (-6.3 +/- 15.0 mm Hg, p = 0.08). Cst increased with VT reduction (+ 3.1 +/- 1.8 ml/cm H2O). There was only a modest correlation (r = +0.42, p = 0.06) between delta Q percent and delta Cst following VT reduction. VT reduction at high level PEEP may yield a significant improvement in Q and net O2 delivery, but the degree of hemodynamic improvement is variable and is not reliably predicted noninvasively by measurement of Cst.