肺复张联合双水平气道正压通气治疗急性呼吸窘迫综合征合并气胸

机械通气是治疗急性呼吸窘迫综合征(ARDS)的主要方法.如果ARDS同时合并气胸,将大大增加治疗难度.本院2006年3月至2008年8月在胸腔闭式引流通畅基础上,采用肺复张联合双水平气道正压(BIPAP)通气与小潮气量(VT)机械通气治疗7例ARDS合并气胸患者,报告如下.     

改良叹气法肺复张对急性呼吸窘迫综合征疗效的影响

目的 在小潮气量通气策略基础上,对急性呼吸窘迫综合征患者实施改良叹气法肺复张治疗,观察改良叹气法肺复张对急性呼吸窘迫综合征的疗效,为改良叹气法肺复张的应用提供依据.方法 选择2006-11～2008-11我院ICU收治的30例ARDS患者.采用压力控制辅助通气模式,限制吸气压≤30 cm H2O,潮气量为6～8 mL/kg.研究分三期:基础期2 h(小潮气量通气+呼气末正压)、叹气期1 h(小潮气量通气+呼气末正压+叹气)、叹气后期1 h(小潮气量通气+呼气末正压).记录并比较各期患者的氧合情况、通气及酸碱情况、呼吸力学指标、血流动力学指标、气压伤的发生情况等.结果 ①氧合指数(PaO2/FiO2)明显改善,差异有统计学意义(P<0.05).但是随着叹气的结束又恢复到叹气前的水平.②二氧化碳分压(PaCO2)有所降低,差异有统计学意义(P<0.05).但是随着叹气的结束又恢复到叹气前水平.③静态顺应性明显改善,差异有统计学意义(P<0.05).但是随着叹气结束又恢复到叹气前的水平.④心率、平均动脉压及中心静脉压变化差异无统计学意义(P均>0.05).⑤未发生气压伤.结论 持续的改良叹气能明显改善患者的氧合状态及胸肺顺应性,且安全易行,对血流动力学干扰较小,但疗效的维持时间不稳定.     

俯卧位通气加肺复张对急性呼吸窘迫综合征的作用

目的 评价俯卧位通气(PPV)联合肺复张(RM)对急性呼吸窘迫综合征(ARDS)犬的肺保护作用及机制.方法 经股静脉快速注入油酸建立犬ARDS模型,容积控制通气,在小潮气量(VT,10 ml/kg)+高呼气末正压(PEEP,16 cm H2O,1 cm H2O=0.098 kPa)通气基础上,按随机数字表法分为仰卧位组、俯卧位组、仰卧+RM组、俯卧+RM组,每组6只.测定通气后0.5、2和4 h血清细胞因子.4 h后经股动脉放血处死动物,开胸取肺;取左肺组织制备匀浆,测定细胞因子;取右肺测定湿/干重(W/D)比值及制备病理切片,行病理评分.结果 ①通气4 h时仰卧+RM组血清白细胞介素-8(IL-8)浓度明显高于其他3组(P均<0.05),且仰卧+RM组血清肿瘤坏死因子-α(TNF-α)浓度明显高于俯卧位组及俯卧+RM组(P均<0.05).②俯卧位组及俯卧+RM组背侧肺组织匀浆中IL-8浓度明显低于仰卧位组(P均<0.05),TNF-α浓度明显低于仰卧+RM组(P均<0.05).③俯卧位组、俯卧+RM组右肺W/D比值明显低于仰卧位组及仰卧+RM组(P均<0.05).④俯卧位组及俯卧+RM组背侧病理评分显著低于仰卧位组及仰卧+RM组(P均<0.05).结论 在犬ARDS模型中,予以小VT+PEEP的肺保护性通气时,在俯卧位实施RM可以减轻肺损伤.     

肺复张对急性呼吸窘迫综合征患者血管外肺水的影响

目的 探讨肺复张(RM)策略对急性呼吸窘迫综合征(ARDS)患者血管外肺水(EVLW)的影响.方法 采用随机对照病例研究方法,将20例ARDS患者随机分为RM组和对照组.按肺保护性通气策略的原则给患者进行机械通气;用双水平气道正压(BIPAP)通气模式进行RM,每8 h重复1次,连续7 d或至脱机前;除RM外,其余治疗两组相同.记录患者的基线资料和每日RM结束后的EVLW、血管外肺水指数(EVLWI)、呼吸力学参数、氧合指数(PaO2/FiO2)、中心静脉压(CVP)、血浆胶体渗透压(COP)以及糖皮质激素、肾上腺素能药物用量和24 h液体出入量平衡等影响EVLW各因素的数值.结果 RM组和对照组EVLW、EVLWI随时间延长呈逐渐降低趋势,但两组间比较差异无统计学意义(P均>0.05).两组间CVP、COP和去甲肾上腺素、氢化可的松用量比较差异均无统计学意义(P均>0.05);RM组多巴胺用量在4 d时明显少于对照组(P<0.05);液体出入量平衡RM组7 d时为负平衡,对照组则为正平衡(P<0.05).RM组平均气道压(Pmean)的均值[(18.8±3.2)cm H2O(1 cm H2O=0.098 kPa)]和肺准静态顺应性(Cstat)的均值[(36.5±14.5)ml/cm H2O]均明显高于对照组[(16.6±3.9)cm H2O和(29.3±12.0)ml/cm H2O,P均<0.05];其中RM组5 d时Cstat大于2 d和3 d时(P均<0.05).两组间PaO2/FiO2比较则未见明显差异(P均>0.05).结论 针对ARDS患者实施的RM治疗并没有明显影响EVLW,而仅起到了改善肺呼吸力学特征的作用.本研究中所涉及的影响肺水的因素并未影响肺水的形成和清除.     

肺复张策略在急性呼吸窘迫综合征治疗中的应用

目的:探讨肺复张策略在急性呼吸窘迫综合征(ARDS)治疗中的应用效果。方法:将40例ARDS患者随机分为A组和B组各20例,A组采用保护性通气策略,B组采用肺复张策略,观察两组的疗效和并发症发生情况。结果:两组治疗3 d后PaO2/FiO2、SaO2及PaO2较治疗前有明显改善(P<0.05);B组与A组治疗3 d后PaO2/FiO2、SaO2及PaO2比较差异有统计学意义(P<0.05);B组机械通气时间I、CU住院时间少于A组(P<0.05)。结论:肺复张策略可改善ARDS患者的血氧饱和度,对血流动力学影响短暂,安全有效。     

控制性肺膨胀联合肺保护性通气策略在急性呼吸窘迫综合征的临床应用研究

目的观察控制性肺膨胀（SI）联合肺保护性通气策略对急性呼吸窘迫综合征（ARDS）患者的临床疗效。方法以25例ARDS病程早期的患者为研究对象，依据肺保护性通气策略确定基础通气模式，分别测定SI前、SI时，SI后10min、1h、2h、3h、4h、5h的肺气体交换、肺力学、血液动力学的变化。结果25例中，有2例因血压明显下降而退出，18例在实施SI后Sao2均有明显上升，有效率78．3％。SI时Sao2均有明显下降，但此后迅速上升，10min-1h时达到最高值，疗效可维持4h；SI能显著改善肺顺应性（Cdyn），SI后1h时平台压（Pplat）即有明显下降，气道峰压（PIP），平均气道压（Pmean）在4h时下降明显；SI时CVP明显增加，但在SI结束后很快恢复到SI前水平。25例中未有气压伤的表现。结论SI联合肺保护性通气策略能有效复张塌陷的肺泡，降低气道压力，改善肺顺应性，增加氧合，对循环系统影响小，安全有效，但具有时效性，对于原发于肺部病变所致的ARDS合并血液动力学不稳定者应用SI要慎重。     

保护性通气策略在急性呼吸窘迫综合征中的应用

研究表明 ,机械通气 (ＭＶ)可引起肺损伤或已损伤肺的再损伤(ｖｅｎｔｉｌａｔｏｒ -ｉｎｄｕｃｅｄｌｕｎｇｉｎｊｕｒｙ ,ＶＩＬＩ) ,ＶＩＬＩ已成为影响急性呼吸窘迫综合征(ＡＲＤＳ)预后的主要因素之一[1 ,2 ] 。因此 ,近年提出了以“小潮气量 ,最佳ＰＥＥＰ”为主要内容的保护性通气策略[2 ,3] 。我们采取保护性肺通气治疗 2 0例ＡＲＤＳ患者 ,现报告如下。一、对象与方法1.对象 :2 0例患者 ,男 13例 ,女7例 ,平均年龄 (5 3± 19)岁。基础原发病有重症胰腺炎 ,坏死性肠梗阻 ,肺癌肺叶切除术 ,胃癌根治术 ,食管癌根治术 ,胸腹部联合伤术…     

肺复张对急性呼吸窘迫综合征患者呼吸力学及血管外肺水指数的影响

目的 探讨肺复张(RM)对急性呼吸窘迫综合征(ARDS)患者呼吸力学及血管外肺水指数(EVLWI)的影响.方法 采用随机对照病例研究方法,选择30例ARDS患者,随机(随机数字法)分为RM组和Non-RM组.RM组:保护性肺通气稳定后0.5 h开始RM治疗,每12 h重复1次RM,连续3d.Non-RM组:保护性肺通气治疗,不使用RM.收集两组患者治疗前、治疗12 h,24 h,48 h,72 h各时间点氧合指数(PaO2/FiO2)、气道峰压(PIP)、气道平台压(Pplat)、静态肺顺应性(Cst)及EVLWI数据;监测RM前后血流动力学变化.数据处理采用单因素方差分析、成组t检验和Fisher确切概率法.结果 ①治疗后两组患者PaO2/FiO2均呈上升趋势,在12 h,24 h,48 h,72 h同时间点比较RM组高于NonRM组(P＜0.05);PIP、Pplat值在治疗后均呈下降趋势,RM组低于Non-RM组(P＜0.05),Cst在治疗后呈升高趋势,RM组高于Non-RM组(P＜0.05).②治疗后两组EVLWI均呈下降趋势,组内各时间点比较差异有统计学意义(F值分别为22.392、8.147,均P＜0.01);在12 h,24 h,48 h,72 h同时间点两组EVLWI比较,RM组低于Non-RM组(P＜0.05或P＜0.01).③RM时有一过性血流动力学变化,与RM前比较差异有统计学意义(P＜0.01),但RM结束后120 s与RM前比较差异无统计学意义(P＞0.05).结论 RM可以减少ARDS患者EVLWI,改善肺氧合及肺顺应性,对血流动力学影响短暂.     

肺复张对肺内/外源性急性呼吸窘迫综合征模型犬呼吸生理和肺形态学影响的比较

目的 探讨以压力-容积(P-V)曲线为导向的肺复张(RM)策略对肺内/外源性急性呼吸窘迫综合征(ARDSexp/ARDSp)模型犬呼吸生理和肺形态学的影响.方法 将24只健康杂种犬按随机数字表法均分为两组,分别以静脉注射油酸0.1 ml/kg复制ARDSexp模型,以气管内注入盐酸2 ml/kg复制ARDSp模型.每种模型再随机均分为肺保护通气策略(LPVS)组和LPVS+RM组.LPVS组采用LPVS进行机械通气(MV);LPVS+RM组先进行以P-V曲线为导向的RM,RM采用压力控制通气(PCV),压力上限为高位转折点(UIP),呼气末正压(PEEP)为低位转折点(LLP)+2 cm H2O(1 cm H2O=0.098 kPa),维持60 s后再按LPVS进行MV.两组MV时间均为4 h.观察动物基础状态(成模前)及RM前后的氧合指数(PaO2/FiO2)、呼吸力学指标变化;采用低流速法记录准静态P-V曲线并计算UIP、LIP ;根据肺CT比较不同肺充气区容积占全肺容积的百分比.结果 成模前和RM前两组PaO2/FiO2及UIP、LIP比较差异均无统计学意义.RM后4 h,两种模型LPVS+RM组PaO2/FiO2和肺顺应性(Crs)均较同模型LPVS组显著升高[ARDSexp模型PaO,/FiO2(mm Hg,1 mm Hg=0.133 kPa):263.9±69.2比182.8±42.8,Crs(ml/cm H2O):11.3±4.2比9.7±3.7;ARDSp模型PaO2/FiO2(mm Hg):193.4±33.5比176.4±40.2,Crs(ml/cm H2O):10.1±3.9比9.0±3.9,P＜0.05或P＜0.01],气道压力明显低于同模型LPVS组[ARDSexp模型吸气峰压(PIP,cm H2O):24.1±7.4比30.2±8.5,气道平台压(Pplat,cm H2O):19.1±7.3比25.6±7.7;ARDSp模型PIP(cm H2O):26.6±8.4比29.6±10.3,Pplat(cm H2O):21.9±7.3比25.1±8.4,P＜0.05或P＜0.01];且ARDSexp模型改善程度较ARDSp模型更为显著(P＜0.05或P＜0.01).两种模型LPVS+RM组肺组织闭合区和充气不足区所占比例均较同模型LPVS组明显减少,正常充气区所占比例明显增加[ARDSexp模型闭合区:(9.9±3.1)%比(16.3±5.2)%,充气不足区:(10.2±4.2)%比(23.4±6.7)%,正常充气区:(76.2±12.3)%比(57.5±10.1)%;ARDSp模型闭合区:(14.3±4.8)%比(1 8.2±5.1)%,充气不足区:(17.4±6.3)%比(24.1±5.9)%,正常充气区:(63.2±10.7)%比(54.6±11.3)%,P＜0.05或P＜0.01];且ARDSexp模型各充气区所占比例改善程度均明显优于ARDSp模型(均P＜0.05).结论 对于不同原因ARDS,以P-V曲线为导向的RM均具有增加肺氧合、改善肺顺应性和肺组织通气的作用,且对ARDSexp的治疗效果明显优于ARDSp.

Abstract：

Objective To determine effects of recruitment maneuver (RM) guided by pressure-volume (P-V) curve on respiratory physiology and lung morphology in canine models of acute respiratory distress syndrome of pulmonary or extrapulmonary origin (ARDSp and ARDSexp). Methods Twenty-four healthy dogs were randomly divided into two groups with 12 dogs each: ARDSexp and ARDSp. Each dog in ARDSexp group was injected with oleic acid 0. 1 ml/kg through femoral vein, and each dog in ARDSp group received hydrochloric acid 2 ml/kg via trachea. Subsequently, dogs with both models were randomly subdivided into lung protective ventilation strategy (LPVS) group and LPVS+RM group, respectively. Dogs in LPVS group were given LPVS only without RM. RM guided by P-V curve was performed in LPVS+RM group followed by LPVS and pressure controlled ventilation (PCV) mode was selected. Phigh was set at upper inflection point (UIP) of the P-V curve, positive end-expiratory pressure (PEEP) was set at lower inflection point (LIP)+2 cm H2O (1 cm H2O=0. 098 kPa), and the duration of RM was 60 seconds. The duration of mechanical ventilation (MV) in both subgroups was 4 hours. The oxygenation index (PaO2/FiO2), relative lung mechanical indexes were measured in two ARDS models before establishment of ARDS model, and before and after RM. The UIP and LIP were calculated with P-V curve. The percentage of different volume in ventilation of lung accounting for total lung volume was compared by CT scan.Results The PaO2/FiO2, UIP and LIP did not showed significant differences among all groups before ARDSand before RM. PaO2/FiO2 and respiratory system compliance (Crs) were significantly elevated in LPVS+RM group of both models 4 hours after RM compared with corresponding LPVS group [PaO2/FiO2(mm Hg,1 mm Hg=0. 133 kPa) of ARDSexp model: 263. 9±69. 2 vs. 182.8±42. 8, Crs (ml/cm H2O) of ARDSexp model: 11.3±4. 2 vs. 9. 7±3. 7; PaO2/FiO2(mm Hg) of ARDSp model: 193. 4±33.5 vs. 176. 4±40. 2, Crs (ml/cm H2O) of ARDSp model: 10.1±3.9 vs. 9.0±3.9, P＜0. 05 or P＜0.01], and the airway pressure was significantly declined compared with corresponding LPVS group [peak inspiratory pressure (PIP),cm H2O) of ARDSexp model: 24. 1±7. 4 vs. 30. 2±8. 5, plateau pressure (Pplat, cm H2O) of ARDSexp model: 19.1±7.3 vs. 25.6±7.7; PIP (cm H2O) of ARDSp model: 26.6±8.4 vs. 29.6±10.3, Pplat (cm H2O) of ARDSp model: 21.9±7. 3 vs. 25.1±8.4, P＜0. 05 or P＜0. 01]. Moreover, PaO2/FiO2, Crs,PIP and Pplat were improved better in ARDSexp model than ARDSp model (P＜ 0. 05 or P＜ 0. 01).Compared with LPVS maneuver, RM plus LPVS maneuver could significantly decrease the proportion of closure and hypoventilation region, and increase the proportion of normal ventilation region in both models [closure region of ARDSexp model : (9.9±3.1) % vs. (16. 3± 5. 2) %, hypoventilation region of ARDSexp model: (10. 2±4.2)% vs. (23. 4±6. 7)%, normal ventilation region of ARDSexp model: (76. 2±12. 3)%vs. (57.5±10. 1)%; closure region of ARDSp model: (14.3±4. 8)% vs. (18. 2±5.1)%, hypoventilation region of ARDSp model : (17.4±6. 3) % vs. ( 24. 1 ± 5. 9) 0%, normal ventilation region of ARDSp model :(63. 2 ± 10. 7 ) % vs. ( 54. 6±11.3 ) %, P ＜ 0. 05 or P ＜ 0. 01]. All of the ventilation regions were better improved with ARDSexp model than ARDSp model (all P＜0. 05). Conclusion RM guided by P-V curve could help obtain better oxygenation, improve pulmonary compliance and lung ventilation in ARDSexp and ARDSp, and better treatment effects are seen in ARDSexp dogs than ARDSp dogs.     

急性呼吸窘迫综合征的治疗进展--保护性肺通气

随着急性呼吸窘迫综合征 (acute respiratory distresssyndrome,ARDS)发病机理的不断研究 ,机械通气治疗ARDS患者已逐渐被人们接受。在 1994年 [1 ] 美国 -欧洲ARDS学会就 ARDS简单定义如下 :1急性突发症状 ;2Pa O2 /Fi O2 <2 0 0 mm Hg;3胸片示 :双肺渗出改变 ;4肺毛细血管嵌楔压≤ 18mm Hg;5无左房压增高的体征。从临床角度观察对临床医生有用的是机械辅助通气领域。1　新的通气策略ARDS患者由于严重低氧 ,故需要机械通气以利于气体交换。由于更好的了解了疾病过程 ,现在主要考虑 ARDS患者如何进行机械通气。目前最主要的概念…     

Effects of vertical positioning on gas exchange and lung volumes in acute respiratory distress syndrome

Objective Supine position may contribute to the loss of aerated lung volume in patients with acute respiratory distress syndrome (ARDS). We hypothesized that verticalization increases lung volume and improves gas exchange by reducing the pressure surrounding lung bases.Design and setting Prospective observational physiological study in a medical ICU.Subjects and intervention In 16 patients with ARDS we measured arterial blood gases, pressure-volume curves of the respiratory system recorded from positive-end expiratory pressure (PEEP), and changes in lung volume in supine and vertical positions (trunk elevated at 45° and legs down at 45°).Measurements and results Vertical positioning increased PaO₂ significantly from 94 ± 33 to 142 ± 49 mmHg, with an increase higher than 40% in 11 responders. The volume at 20 cmH₂O measured on the PV curve from PEEP increased using the vertical position only in responders (233 ± 146 vs. –8 ± 91 ml in nonresponders); this change was correlated to oxygenation change (ρ = 0.55). End-expiratory lung volume variation from supine to vertical and 1 h later back to supine, measured in 12 patients showed a significant increase during the 1-h upright period in responders (n = 7) but not in nonresponders (n = 5; 215 ± 220 vs. 10 ± 22 ml), suggesting a time-dependent recruitment.Conclusions Vertical positioning is a simple technique that may improve oxygenation and lung recruitment in ARDS patients.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

肺保护性通气对急性呼吸窘迫综合征家兔肺外器官炎症反应的影响

目的　研究肺保护性通气对急性呼吸窘迫综合征 (ARDS)肺外器官炎症反应的影响。方法　用生理盐水肺泡灌洗法复制ARDS家兔模型 ,分为 6组 (1)正常对照组 ;(2 )ARDS模型组 (ARDS) ;(3)小潮气量 (VT) +最佳呼气末正压 (PEEP)组 (LVBP) ;(4)常规VT+最佳PEEP组 (NVBP) ;(5 )小VT+高PEEP组 (LVHP) ;(6 )高VT+零PEEP组 (HVZP)。后 4组机械通气 4h后 ,用逆转录PCR法 (RT PCR)检测动物肝肠组织肿瘤坏死因子 (TNF)α和白介素 (IL) 10mRNA表达 ,酶联免疫吸附法 (ELISA)测定肝肠组织TNF α及IL 10浓度。结果　LVBP组肝组织TNF α和IL 10mRNA表达分别为 (42± 9)和 (2 5±10 ) ,与ARDS模型组相比较 ,差异无显著性 ,分别为 [(37± 7)和 (2 5± 4 ) ],但显著低于NVBP [分别(5 6± 7)和 (36± 8) ]、LVHP [(5 3± 10 )和 (35± 5 ) ]和HVZP组 [(70± 10 )和 (46± 5 ) ]。LVHP组TNF α和IL 10mRNA表达明显高于LVBP组 ,但明显低于HVZP组。LVBP组肝组织TNF α和IL 10浓度与ARDS组无明显差异 ,但显著低于NVBP、LVHP和HVZP组。HVZP组肝组织TNF α和IL 10浓度最高 ,不但高于LVBP组 ,也高于LVHP组。LVBP组的肠组织的TNF αmRNA表达为 (38± 11) ,与ARDS组比较无显著差异 ,但显著低于NVBP (5 1± 9)、LVHP (5 0± 11)和HVZP组     

高呼气末正压加肺复张治疗急性呼吸窘迫综合征

目的 评价高呼气末正压(PEEP)加肺复张(RM)治疗急性呼吸窘迫综合征(ARDS)的临床疗效和安全性.方法 选择2008年6月至2010年5月贵阳医学院附属医院内科重症监护病房(MICU)收治的ARDS患者38例,按信封法随机分为RM组和非RM组,每组19例.两组均采用压力支持通气(PSV)模式行机械通气,尽可能在吸入氧浓度(FiO2)＜0.60时达到目标氧合的最小PEEP水平,限制平台压≤30 cm H2O(1 cm H2O=0.098 kPa).RM时FiO2调至1.00,压力支持水平调至0,将PEEP升至40 cm H2O,持续30 s后再降低,8 h 1次,连续5 d.记录基础状态和5 d内的机械通气参数、血气分析结果及生命体征,比较两组氧合改善和肺损伤指标变化,观察RM的不良反应和气压伤发生率.结果 ①两组患者基础状态及机械通气参数均无明显差异.②两组动脉血氧分压(PaO2)和氧合指数(PaO2/FiO2)均明显改善,且RM组明显优于非RM组[PaO2(mm Hg,1 mm Hg=0.133 kPa)2 d:85.8±21.3比73.5±18.7,3 d:88.6±22.8比74.3±19.8,4 d:98.8±30.7比79.3±19.3,5 d:105.5±29.4比84.4±13.8;PaO2/FiO2(mm Hg)4 d:221.8±103.5比160.3±51.4,5 d:239.6±69.0比176.8±45.5,均P＜0.05].③两组呼出气冷凝液(EBC)中过氧化氢(H2O2)和白细胞介素-6(IL-6)水平均呈下降趋势,RM组下降幅度更明显[5 d时H2O2(μmol/L):0.04±0.02比0.10±0.03;IL-6(ng/L):4.12±2.09比9.26±3.47,均P＜0.05].④两组均无气压伤发生,心率无明显变化,无心律失常发生,中心静脉压和平均动脉压无明显变化.结论 高PEEP加RM可增加气体交换,改善氧合,减少呼吸机相关性肺损伤(VALI).应用RM比较安全,耐受性好,临床观察未见低氧血症、气压伤和血流动力学异常.

Abstract：

Objective To investigate the clinical effects and safety degree of high positive endexpiratory pressure (PEEP) combined with lung recruitment maneuver (RM) in patients with acute respiratory distress syndrome (ARDS). Methods Thirty-eight patients in medical intensive care unit (MICU) of Affiliated Hospital of Guiyang Medical College suffering from ARDS admitted from June 2008 to May 2010 were enrolled in the study. With the envelope method they were randomized into RM group and non-RM group, with n= 19 in each group. All patients received protective ventilation: pressure support ventilation (PSV) with plateau pressure limited at 30 cm H2O (1 cm H2O=0. 098 kPa) or lower. PEEP was set at the minimum level with fraction of inspired oxygen (FiO2) ＜0. 60 and partial pressure of arterial oxygen (PaO2) kept between 60 and 80 mm Hg (1 mm Hg=0. 133 kPa). RM was conducted by regulating FiO2 to 1.00, support pressure to 0, PEEP increased to 40 cm H2O and maintained for 30 seconds before lowering, and this maneuver was repeated every 8 hours for a total of 5 days. Base status, ventilation parameters, blood gas analysis and vital signs were obtained at baseline and for the next 5 days. Oxygenation status and lung injury indexes were compared between RM group and non-RM group, the adverse effects of (PaO2/FiO2) were both increased in RM group and non-RM group, but the values were higher in RM group [PaO2 (mm Hg) 2 days: 85.8± 21.3 vs. 73. 5± 18. 7, 3 days : 88. 6± 22. 8 vs. 74. 3 ±19. 8, 4 days : 98. 8 ±30. 7 vs. 79. 3±19. 3, 5 days: 105.5±29.4 vs. 84. 4±13. 8; PaO2/FiO2(mm Hg) 4 days: 221.8±103. 5 vs.interleukin-6 (IL-6) concentration in exhaled breath condensate (EBC) decreased in both groups but lower in RM group with significant difference [5 days H2O(μmol/L): 0. 04 ± 0. 02 vs. 0.10 ± 0.03 ; IL-6 (ng/L):No significant changes in heart rate were found during RM. Central venous pressure and mean arterial pressure remained unchanged after RM. Conclusion High level PEEP combined with RM can improve gas exchange and oxygenation, decrease ventilator associated lung injury (VALI). RM was safe and had good tolerance, no hypoxemia, barotrauma and hemodynamic instability were observed.     

Effects of periodic lung recruitment maneuvers on gas exchange and respiratory mechanics in mechanically ventilated acute respiratory distress syndrome (ARDS) patients

Objective: We wished to investigate whether volume recruitment maneuvers (VRMs) could improve alveolar recruitment and oxygenation in acute respiratory distress syndrome (ARDS) patients, ventilated at relatively low positive end-expiratory pressure (PEEP). Setting: General intensive care unit (ICU) located in a teaching hospital. Patients: 15 PEEP responder ARDS patients undergoing continuous positive pressure ventilation (CPPV) with sedation and muscle paralysis. Interventions: We identified a low (9.4 ± 3 cmH₂O) and a high (16.0 ± 2 cmH₂O) level of PEEP associated with target oxygenation values. Using a custom modified mechanical ventilator, we applied in random order three steps lasting 30 min: (1) CPPV at the low PEEP level (CPPV lo); (2) CPPV at the high PEEP level (CPPV hi); (3) CPPV at low PEEP with the superimposition of periodic VRMs (CPPV vrm). VRMs were performed twice a minute by increasing PEEP to the high level for two breaths. Each brace of two breaths was spaced 30 seconds from the preceding one. Measurements and results: We measured gas exchange, hemodynamics, respiratory mechanics, and the end expiratory lung volume (EELV). Compared to CPPVlo, CPPVvrm resulted in higher PaO₂ (117.9 ± 40.6 vs 79.4 ± 13.6 mmHg, P < 0.01) and EELV (1.50 ± 0.62 vs 1.26 ± 0.50 l, P < 0.05), and in lower venous admixture (Qva/Qt) (0.42 ± 0.07 vs 0.48 ± 0.07, P < 0.01). During CPPVhi, we observed significantly higher PaO₂ (139.3 ± 32.5 mmHg) and lower Qva/Qt (0.37 ± 0.08) compared to CPPVlo (P < 0.01) and to CPPVvrm (P < 0.05). Conclusions: VRMs can improve oxygenation and alveolar recruitment during CPPV at relatively low PEEP, but are relatively less effective than a continuous high PEEP level. Received: 31 May 1999 Final revision received: 19 October 1999 Accepted: 10 December 1999     

小潮气量通气加肺复张法对急性呼吸窘迫综合征疗效的影响

目的在小潮气量（VT）机械通气的基础上．观察应用肺复张法（RM）治疗急性呼吸窘迫综合征（ARDS）的临床疗效，为临床RM的使用提供依据。方法选择2003年1月-2004年3月北京复兴医院重症监护治疗病房（ICU）收治的28例ARDS患者，随机分为小VT＋RM组（RM组）和小VT组（non—RM组）。第一个24h采用容量控制通气（CMV）．24h后根据病情选择机械通气方式。VT 6ml／kg；尽可能在吸入氧浓度（FiO2）〈0．60时达目标氧合的最小呼气末正压（PEEP）水平，限制平台压≤30cm H2O（1cm H2O=0．098kPa）。RM为吸入纯氧，持续气道正压（CPAP）40cm H2O．持续40s，8h 1次，共5d。除RM外．其他治疗相同。记录基础状态和连续5d的机械通气参数、血气分析结果及生命体征，比较两组氧合改善和肺损伤指标变化，观察RM的不良反应和气压伤发生率。结果①两组动脉血氧分压和氧合指数（PaO2／FiO2）均明显改善，差异有显著性（P均〈0．05）。②两组白细胞介素-6（IL-6）水平均呈下降趋势．RM组下降幅度更明显，差异有显著性（P〈0．05）。③两组均无气压伤发生。④RM后心率无明显变化，也无其他心律失常发生；平均动脉压也无明显波动。结论反复多次RM可增加气体交换，改善氧合，进一步减少呼吸机相关性肺损伤（VALI）。应用RM较安全，简便易行，耐受性好，临床观察未见低氧血症和对血流动力学的明显影响。     

Lung recruitment maneuver effects on respiratory mechanics and extravascular lung water index in patients with acute respiratory distress syndrome

BACKGROUND:

Animal experiments showed that recruitment maneuver (RM) and protective ventilation strategy of the lung could improve oxygenation and reduce extravascular lung water. This study was to investigate the effects of RM on respiratory mechanics and extravascular lung water index (EVLWI) in patients with acute respiratory distress syndrome (ARDS).

METHODS:

Thirty patients with ARDS were randomized into a RM group and a non-RM group. In the RM group, after basic mechanical ventilation stabilized for 30 minutes, RM was performed and repeated once every 12 hours for 3 days. In the non-RM group, lung protective strategy was conducted without RM. Oxygenation index (PaO₂/FiO₂), peak inspiratory pressure (PIP), Plateau pressure (Pplat), static pulmonary compliance (Cst) and EVLWI of patients before treatment and at 12, 24, 48, 72 hours after the treatment were measured and compared between the groups. Hemodynamic changes were observed before and after RM. One-way ANOVA, Student''s t test and Fisher''s exact test were used to process the data.

RESULTS:

The levels of PaO₂/FiO₂ and Cst increased after treatment in the two groups, but they were higher in the RM group than in the non-RM group (P<0.05). The PIP and Pplat decreased after treatment in the two groups, but they were lower in the RM group than in the non-RM group (P<0.05). The EVLWI in the two groups showed downward trend after treatment (P<0.05), and the differences were signifcant at all time points (P<0.01); the EVLWI in the RM group was lower than that in the non-RM group at 12, 24, 48 and 72 hours (P<0.05 or P<0.01). Compared with pre-RM, hemodynamics changes during RM were significantly different (P<0.01); compared with pre-RM, the changes were not significantly different at 120 seconds after the end of RM (P>0.05).

CONCLUSIONS:

RM could reduce EVLWI, increase oxygenation and lung compliance. The effect of RM on hemodynamics was transient.KEY WORDS: Lung recruitment maneuver, Acute respiratory distress syndrome, Respiratory mechanics, Extravascular lung water index, Hemodynamics, Lung protective ventilation, Oxygenation index     

Effects of pulmonary stretch reflex on lung injury in rabbits with acute respiratory distress syndrome

BACKGROUND:

Pulmonary stretch reflex plays an important role in regulation of respiratory movement. This study aimed to evaluate the effect of pulmonary stretch reflex on lung injury in rabbits with acute respiratory distress syndrome (ARDS).

METHODS:

ARDS rabbits were given intratracheal infusion of hydrochloric acid and ventilated with neurally adjusted ventilatory assistance (NAVA) with a tidal volume (V_T) of 6 mL/kg and the electrical activity of diaphragm (EAdi)-determined positive end expiratory pressure. After isolation of the bilateral vagus nerve trunk, the rabbits were randomized into two groups: sham operation (SHAM) group (n=5) and bilateral vagotomy (VAG) group (n=5). Gas exchange and respiratory mechanics were detected at baseline, after lung injury and 1, 2, and 3 hours after ventilation respectively. Pulmonary permeability index, pathological changes and inflammatory response were also measured.

RESULTS:

Compared with the SHAM group, PaO₂/FiO₂ in the VAG group decreased significantly 2 and 3 hours after ventilation (P<0.05). There was no significant difference in PaCO₂ between the SHAM and VAG groups (P>0.05), and the VAG group had a high V_T, peak pressure (Ppeak), and mean pressure (Pm) compared with the SHAM group 1, 2, 3 hours after ventilation (P<0.05). Compared to the SHAM group, dead space fraction (V_D/V_T) and respiratory system elastance (Ers) in the VAG group increased (P<0.05) and static pulmonary compliance (Cst) decreased markedly (P<0.05) after ventilation for 3 hours. Lung wet/dry weight ratio (W/D) (8.4±1.2 vs. 6.6±1.0), lung injury score (6.3±1.8 vs. 3.8±1.3), tumor necrosis factor-α (TNF-α) (779±372 pg/mL vs. 355±130 pg/mL) and interleukin-8 (IL-8) (169±21 pg/mL vs. 118±17 pg/mL) increased significantly in the VAG group compared with the SHAM group (P<0.05).

CONCLUSION:

Lung injury is aggravated after bilateral vagotomy, demonstrating that pulmonary stretch reflex may have protective effect on the lung.KEY WORDS: Pulmonary stretch reflex, Vagus nerve, Lung injury, Acute respiratory distress syndrome, Electrical activity of diaphragm, Mechanical ventilation     

猪肺表面活性物质治疗肺灌洗诱发的兔急性呼吸窘迫综合征的实验研究

目的本实验观察了猪肺表面活性物质（PPS）混悬液对肺灌洗致免急性呼吸窘迫综合征（ARDS）的治疗作用。方法将31只兔分为生理盐水对照组和高、中、低三个不同剂量PPS给药组，用生理盐水在体肺灌洗诱发兔ARDS后，经气管分别滴入生理盐水或80mg／kg、120mg／kg、160mg／kg的PPS。于兔灌洗前、灌洗后和给药后不同时间抽取动脉血进行血气分析。实验过程中观察呼吸频率．动物的生存时间。共观测8h。实验结束后，处死动物取肺甲醛固定后行病理学检查。结果肺灌洗后兔的呼吸频率、血气指标和肺病理学的改变均符合ARDS表现，肺灌洗后生理盐水治疗组兔在1h内死亡率为11／12。而PPS气道给药三组除了低剂量组有2只兔的生存时间超过6h．但小于8h外，中高剂量组所有兔的存活时间均超过8h。三个PPS剂量组给药后15-30min兔的呼吸频率均明显减慢，动脉血PaO2显著提高．PaCO2和血pH分别在1h和6h降至正常。肺泡萎陷、肺出血和炎细胞浸润状况也明显改善。中、高剂量组在提高PaO2．延长动物生存率和改善肺病理变化方面比低剂量组效果更好。结论PPS对于兔肺灌洗型ARDS具有明显的治疗作用。     

俯卧位通气对急性肺损伤和急性呼吸窘迫综合征临床疗效影响的Meta分析

目的 系统评价俯卧位通气(PPV)对我国急性肺损伤(ALI)和急性呼吸窘迫综合征(ARDS)患者的短期临床疗效.方法 利用Cochrane系统评价法,全面检索2000年至2009年国内公开发表的所有ALI与ARDS患者PPV的临床研究资料.对纳入研究独立进行质量评价、资料提取、交叉核对后行Meta分析.结果 纳入研究8项共184例患者,PPV时患者动脉血氧分压(PaO2)、氧合指数(PaO2/FiO2)、呼吸系统总顺应性(C)均显著升高;动脉血二氧化碳分压(PaCO2)、中心静脉压(CVP)、呼吸道峰压(PIP)和呼吸系统总阻力(Raw)无显著的变化;心率(HR)与平均动脉压(MAP)显著升高. 结论 ALI与ARDS患者行PPV可增加呼吸系统总顺应性,改善患者低氧血症,相关临床研究结果基本一致.但因Meta分析的自身局限性,我们仍急需开展设计严谨的高质量大样本临床研究,明确PPV临床疗效、作用机制、科学的操作流程及PPV对患者血流动力学的影响等临床实际问题,改善国内ALI与ARDS患者的临床护理水平.