反比通气与常规通气治疗犬呼吸窘迫综合征时的呼吸动力学比较.pdf

反比通气与常规通气治疗犬呼吸窘迫综合征时的呼吸动力学比较蹇华胜毕敏摘要目的:探索反比通气的临床应用价值,观察反比通气对呼吸窘迫综合征时呼吸动力学的影响。方法:应用犬油酸型急性呼吸窘迫综合征(ARDS)模型,Siemens 900C呼吸机和HP 1165A监护系统,观察反比通气时的气道峰压、气道阻力、平均气道压和动态胸肺顺应性变化。结果:反比通气组的气道峰压和气道阻力显著低于常规通气组(P均 0101),平均气道压和动态胸肺顺应性显著高于常规通气组(P均 01010105)。结论:反比通气在改善ARDS呼吸动力学方面明显优于常规通气,对ARDS的治疗有一定的临床应用价值。关键词反比通气呼吸动力学呼吸窘迫综合征,急性作者单位:630038重庆市第三军医大学西南医院急诊科(蹇华胜),ICU(毕敏)机械通气为治疗急性呼吸窘迫综合征(ARDS)的重要措施之一。有报告认为,气道峰压与肺的气压伤有关,而平均气道压与动脉血氧合和心排血功能有关;气道阻力和胸肺顺应性则与肺间质水肿、气道口径、功能性气道数量有关13。为此,我们通过动物实验,改变吸呼比和气流速度,观察呼吸动力学变化,探讨反比通气的临床应用价值。1材料与方法111实验动物:重庆地区杂种犬14只,由第三军医大学动物室提供,体重912kg,雌雄不拘,随机分为2组:容量控制常规通气组(VC)和反比通气组(IRV)。112方法:实验前动物禁食12小时,肌注氯胺酮10mg?kg,仰卧于动物手术台上,固定四肢,气管插管,美国产HP 1165A监护系统 导心电连续监测,右股静脉缓慢注入油酸011m l?kg,动物呼吸频率立即增快,呼吸困难,氧分压下降,为了确保测定值不受自主呼吸影响,给予静脉复合麻醉(2%普鲁卡因+0112%哌替啶+0104%琥珀胆碱),0105m lm in1?kg输液泵匀速输入。VC组给予Siemens 900C呼吸机常规通气,潮气量1618m l?kg,呼吸频率15次?分,呼气末正压通气(PEEP)为015kPa(1kPa=715mmHg),吸气时间33%,吸呼比(IE)为12。IRV组也用Siemens 900C呼吸机通气,潮气量、呼吸频率和PEEP与VC组相同,吸气时间为66%,IE为21。分别于静注油酸后1、2、4、6小时测定并计算气道峰压(PA P)、平均气道压(MA P)、气道阻力(Raw)和动态胸肺顺应性(Cd),每项指标测定3次,取平均值。113统计学处理,数据用xs表示,组间比较用方差分析,方差不齐者用秩和检验,P 0105为差异有显著性。2结果211犬ARDS模型:经静脉注入油酸后实验犬呼吸频率显著增快,胸廓呼吸动度变浅,呼吸困难,双肺出现湿口 罗音,动脉血氧分压显著下降,肺组织光镜和电镜检查符合ARDS改变。212IRV组与VC组PA P的比较:IRV组各时相点PA P显著低于VC组(P均 0101),平均下降13%16%(见表1)。213IRV组与VC组平均气道压(MA P)的比较:静注油酸后,IRV组各时相点MA P显著高于VC组(P均 01010105),平均上升19%28%(见表2)。214IRV组与VC组Raw的变化:静注油酸后VC组Raw显著高于IRV组(P 0101),平均升高69%80%(如表3)。215IRV组与VC组Cd比较:IRV组各时相点Cd显著高于VC组(P均 01010.05),平均上升30%39%(见表4)。6中国危重病急救医学1997年1月第9卷第1期 1995-2005 Tsinghua Tongfang Optical Disc Co.,Ltd.All rights reserved.表1IRV组与VC组PAP的比较(xs,kPa)动物数(只)静注油酸后时间(h)1246VC组71162901064116570108211729011031172901155IRV组711414010753 311414010693 311450010963 311471010493 3注:与VC组比较:3 3P 0101表2IRV组与VC组MAP的比较(xs,kPa)动物数(只)静注油酸后时间(h)1246VC组70.68401033017000110101724010520172401071IRV组701814010513 3018930118230190401162301906011843注:与VC组比较:3P 0.05,3 3P 0.01表3IRV组与VC组Raw的比较(xs,kPas?L)动物数(只)静注油酸后时间(h)1246VC组70.90401029019520106401994010751105701223IRV组701544010613 301568011833 301588011473 301586011213 3注:与VC组比较:3 3P 0101表4IRV组与VC组Cd的比较(xs,ml?kPa)动物数(只)静注油酸后时间(h)1246VC组71761366143170144121041581811516116117722185IRV组723116491083 3214120491983220101561813209181391983注:与VC组比较:3P 0105,3 3P 01013讨论有报告认为,肺纤维化和肺间质水肿引起的肺僵硬是ARDS机械通气时产生高气道峰压的主要原因,尤其是在大潮气量和高水平PEEP应用时4。而高气道峰压除了可引起肺泡损伤、气体泄漏外,还可引起渗透性肺水肿。有文献报告,中等度气道峰压(35kPa)可引起正常动物与ARDS相类似的渗透性肺水肿5。D reytuss等1报告,将大鼠用峰压为4141kPa呼吸机通气20分钟,有明显的肺水肿和微血管损伤。另有报道,ICU患者气道峰压超过6186kPa,气压伤发生率超过40%6。本研究结果显示:IRV组各时相点峰压均显著低于VC组(P均 0101),平均下降13%16%,推测IRV可减轻气压伤发生率。机械通气时,平均气道压是整个呼吸周期的平均压力,它的大小取决于吸气和呼气压力波形所占的面积大小和各自占用的时间,任何延长吸气时间的方法都将增加平均气道压,增加PEEP也就增加了呼气压力波形所占的面积,平均气道压也随之增大。文献7报告,动脉血氧合直接与平均气道压有关,平均气道压是影响动脉血氧合的共同因素。但是,平均气道压又是影响血流动力学的重要因素2。本研究结果显示,IRV组与VC组相比,平均气道压显著增高,对血流动力学没有影响,与A braham等8的结果相似。另外,对血流动力学的影响还与吸呼比有关,因此在临床上治疗ARDS时,如何选择最佳IRV,以达到最佳氧合。最小峰压,最小气压伤发生率,最小血流动力学影响已成为ARDS呼吸支持的重要课题之一。W right等2观察了10例ARDS患者,发现ARDS患者的动态胸肺顺应性下降,气道阻力增加;动态胸肺顺应性与动脉血氧分压、肺泡7中国危重病急救医学1997年1月第9卷第1期 1995-2005 Tsinghua Tongfang Optical Disc Co.,Ltd.All rights reserved.氧分压的比值(PaO2?PAO2)有关,并认为正是由于气道阻力的增加引起了其它呼吸动力学参数变化。气道阻力增加与以下因素有关3,9:肺组织充血水肿,组织僵硬,弹性差,阻碍了肺的膨胀。气道炎症所致气道高反应性,气道口径变小。严重的急性肺损伤,部分传导性气道的闭合。功能性气道数量减少。本研究结果显示,IRV组气道阻力显著低于VC组(P01010105),动态顺应性显著高于VC组(P 01010105),组内比较差异不显著,与W right等2的结果相似。综上所述,选择适当的IRV具有降低气道峰压、改善动脉血氧合、对血流动力学影响小的优点,故有一定的临床应用价值。4参考文献1Dreytuss D,Basset G,Soler P.Interm ittent positive pres2sure hyperventilation w ith high inflation pressure producesm icrovascular injure in rats.Am Rev Respri Dis,1985,1328802W right P,Bernard G.The role of airflow resistance in pa2tients w ith the adult respiratory distress syndrome.AmRev Respir Dis,1989,13911693Bernard G,Lucht W,N iedermeyer M,et al.Effect of N2acetylcysteine on the pulmonary response to endotoxin inthe awake sheep and upon in vitro granulocyte function.JClin Invest,1984,7317724M atam is D,Lemaire F,Harf A,et al.Total respiratorypressurevolume curves in the adult respiratory distresssyndrome.Chest,1984,86585Parker J,Hernandez L,Longenecker G,et al.Lung edemacaused by high peak inspiratory pressure in dogs:role ofincreased m icrovascular filtration pressure and permeabili2ty.Am Rev Respir Dis,1990,1423216Tsuno K,Pdrato P,kololoow T.Acute respiratory insuffi2ciency induced by mechanical ventilation at peak airwaypressure of 39cm H2O:an experi mental study.Am RevRespir Dis,1985,131?A 1547Pesenti A,M areolin R,Prato P,et al.M ean airway pres2sure vs positive endexpiratory pressure during mechani2cal ventilation.Crit CareM ed,1985,13?348Abraham E,Yoshihara G.Cardiorespiratory effects ofpressure controlled invers ratio ventilation in severe respi2ratory failure.Chest,1989,96?13569Snapper J,Hutchison A,Ogletree M,et al.Effects of cy2clooxygenase inhibitors on the alterations in lung mechan2ics caused by endotoxem ia in the unanesthetized sheep.JClin Invest,1983,72?63(收稿:1995 12 18)非同步容量呼吸机抢救重度河豚毒素中毒1例王海燕1病历简介患者男,30岁。因1天内先后两次进食河豚鱼后,出现四肢麻木、无力,逐渐不能行走,1小时前出现呼吸无力被送入院。入院时查体:体温3615,脉搏86次?分,呼吸15次?分,血压1210?810kPa(1kPa=715mmHg),嗜睡状,急性病容,口唇轻度紫绀,呼吸运动明显减弱,双肺呼吸音明显减弱,四肢肌力 级,膝及踝反射减弱。入院诊断:重度河豚毒素中毒。治疗经过:皮下注射士的宁2mg。供氧:即气管插管接非同步容量电动呼吸机(上海医疗器械四厂生产,SC2型),呼吸频率为18次?分,吸?呼=1?115,最大吸气压力1147kPa(1kPa=10120cmH2O),潮气量0165L。静注速尿20mg。支持疗法。静滴青霉素等防治感染。心电监护,加强护理等。经上述治疗后,患者自觉症状逐渐好转,24小时后撤除呼吸机,患者自主呼吸律整有力,20次?分,再观察30分钟无异常,拔除气管插管,继续治疗两天后痊愈出院。2讨论河豚鱼生长在我省海域里,很容易捕获到,其肉鲜嫩,味美可口,时有误吃中毒者。本例患者第一次尝吃后仅有轻微四肢麻木、无力等症状而不介意,第二次进食后症状加重。河豚毒素存在于河豚鱼的睾丸、卵巢、肝、肠等组织和血液中,它是一种神经毒,进入人体后作用于周围神经与脑干中枢,使之发生麻痹,引起周围的感觉神经麻痹,继而引起运动神经麻痹,最后累及脑干中枢,如呼吸中枢麻痹引起呼吸运动逐渐减弱甚至呼吸停止。本例患者出现呼吸逐渐减弱是使用同步呼吸机的适应证,但当时无同步呼吸机,我们及时地使用非同步呼吸机,并获得成功。我们认为,在呼吸逐渐减弱时应用非同步呼吸机,能供给充足的氧,大大改善由于呼吸减弱造成的低氧状态。在无同步呼吸机的情况下,应急使用非同步呼吸机是可行有效的。(收稿:1995 07 20)作者单位:571400海南省琼海市医院8中国危重病急救医学1997年1月第9卷第1期 1995-2005 Tsinghua Tongfang Optical Disc Co.,Ltd.All rights reserved.ENGL ISHABSTRACTSOFORIGINALARTICLESPreventive and therapeutic effects of an isodam ine inprevention and treatment on acute lung injury inducedby oleic acid?Jing Youling,Yang Qiu,Zheng Junguo,et alChinese Critical Care M edicine,1997,9(1)?2Objective:To investigate the therapeutic and pre2ventive effects of anisodam ine(6542)on acute pul2monary injury induced by oleic acid in rabbits and theirmechanism.M ethods:654 2 was applied in the prophy2laxis and treatment of rabbitsw ith acute lung injury in2duced by oleic acid.The changes of the content of mal2ondialdehyde(MDA)in plasma and lung homogenate,pulmonary surfactant(PS),fibronectin(Fn),lactate de2hydrogenase(LDH)and acid phosphatase(ACP)inplasma were observed.Results:the adm inistration of654 2 could decrease the contents of MDA,LDH andACP,prevent the reduction of PS and Fn,and alleviatethe pulmonary tissue injury.Conclusions:It is suggest2ed that the decrease of PSmay be due to the increase ofMDA,and that 654 2 possesses protective effects onthe acute lung injury induced by oleic acid through amechanism of cellmembrance stabilization.Key words:anisodam ine;malondialdehyde;pulmonarysurfactant;fibronectinComparison of respiratory mechan ics between inverseratio and conventional ventilation in treatment of ca-n ine respiratory distress syndrome.?Jian Huasheng,BiM inChinese Critical CareM edicine,1997,9(1)?6Objective:In ordertoseekanewventilaticmethodforacuterespiratorydistresssyndrome(ARDS)and observe changes of respiratory distresssyndrome.M ethods:The RDS models were made in 14dogs w ith oleic acid.Effects of respiratory mechanicswere observed by using Siemens 900C ventilator andHP1165A monitor during inverse ratio(inspiration:ex2piration=2?1)and conventional(inspiration?expira2tion=1?2)ventilation.Results:The airway peak pres2sure and resistance were lower during inverse ratioventilation than conventional ventilation(P 0101),and the dynam ic compliance and mean airway pressurewere higher in inverse ratio ventilation group than con2ventional ventilation group(P 01010105).Conclu2sions:These findings suggest that the inverse ratio ven2tilation is superior to conventional ventilation in i m2proving respiratory mechanics of the respiratory dis2tress syndrome,and thus could be useful for treatmentof RDS.Key words:inverse ratio ventilation;respiratory me2chanics;acute respiratory distress syndromeEffect of antithrombin 3 on pulmonary and renal ul-trastructural changes in the shock stage of scaldedrats?ZhuW ei,Cai Baoren,Zhao Huijuan,et alChinese Critical CareM edicine,1997,9(1)?9Objective:To study the effect of antithrombin3in the shock stage in burns through the pathologicalchanges of pulmonary and renal ultrastructures in rats.M ethods:20%body surface area,third degree burnswere created in rats and observed w ith electron m icro2scope.The pulmonary and renal sampleswere taken at24 hr afterinjury.Results:In treatment group,alveolarcollapse alleviated;pulmonary alveoloseptal capillarycavities became unobstructed;renal footcell swellingalleviated;m icrothromosiswas not found in the m icro-circulation.Conclusions:It is suggested that antithrom2bin3 can i mprove and deoppilate m icrocirculation sothat the period of tissue ischem ia and anoxia can beshortened and organ damage alleviated.Key words:antithrombin3;burn;pathologic ultra2structural change;ratAcute cerebral ischem ia with lung injury:An experi-mental study?Chen Mane,Zhou Huadong,WangJingzhou,et alChinese Critical Care M edicine,1997,9(1)?11Objective:To investigate the pulmonary injury inearly cerebral ischem ia.M ethods:Bilateral commoncarotid arteries of 12 rats were ligated for 2 hr to cre2ate acute cerebral ischem ia.Results:pH and PaCO2were markedly increased and PaO2was markedly de2creased 2hr after cerebral ischem ia occurred in rats.A lveolar septa were congested and w idened.Type Ialveolar epithelia were swollen,the structure of m ito2chondrial creasts was not clear,and the circular struc2ture ofmultilamellar body in typealvecolar epitheliawas destroyed.Conclusions:Experi mental result sug2gests that the lung was injured in the early stage ofcerebral ischem ia.Key words:cerebral ischem ia;neuronal injury;pul2monary injury;ratChanges of tumor necrosis factorlevels after smokeinhalation injury?Xie Erfan,Yang Zongcheng,L iAoChinese Critical CareM edicine,1997,9(1)?14Objective:To investigate the possible roles of tu2mor necrosis factor(TN F)in the onset and develop2ment of acute lung injury caused by smoke inhalation.M ethods:Follow ing the use of a rat smoke inhalationinjury model,the present study was designed to deter2m ine the dynam ic changes of TN Flevels in plasmaand bronchoalveolar lavage fluid(BAL F)after injury.The concom itant changes of arterial blood gas levels,lung water volume,differential count of white bloodcells in BAL F,and pathomorphology of lung tissueswere also observed.Results:A ni mals showed acute res2piratory failure and serious pulmonary edema aftersmoke inhalation.A lot of inflammatory cells aggregat2ed and infiltrated in the lungs.Both TN Fcontents inplasma and BAL F increased markedly and TN Flevelwas found to have a significantly positive correlationw ith lung water volume and the number of neutrophils06Chinese Critical CareM edicine Vol19 No11 1997 1995-2005 Tsinghua Tongfang Optical Disc Co.,Ltd.All rights reserved.