全身麻醉中应用小潮气量联合低水平呼气末正压通气对老年患者呼吸功能的影响

目的 观察全身麻醉中应用小潮气量(VT)联合低水平呼气末正压通气(PEEP)对老年患者呼吸功能的影响.方法 20例ASAⅠ或Ⅱ级上腹部手术老年患者,随机均分为A组和B组.A组,机械通气模式为间歇正压通气(IPPV)加5cm H2O PEEP,VT=6ml/kg,f=15次/分;B组,机械通气模式为IPPV,VT=9ml/kg,f=12次/分.观察术前(T1)、麻醉插管后30min(T2)、拔管后15min(T3)的动脉氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、肺泡-动脉氧分压差(A-aDO2)、MAP、CVP及术中的气道峰(Ppeak).结果 T3时,A PaO2较B组明显升高(P<0.05),A组A-aDO2较B组明显降低(P<0.05).其他各时点A、B两组PaO2、PaCO2、A-aDO2、MAP、CVP、Ppeak组间比较差异无统计学意义.结论 小潮气量联合低水平PEEP通气能够有效改善老年患者术后低氧血症,减少肺部并发症,更有利于老年患者呼吸功能的恢复,对老年患者血流动力学无明显影响.     

不同通气模式对腹腔肿瘤根治术老年患者围术期炎性反应的影响

目的 评价不同通气模式对腹腔肿瘤根治术老年患者围术期炎性反应的影响.方法 择期拟行腹腔肿瘤根治术的患者60例,年龄65 ～ 80岁,性别不限,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将其随机分为3组(n=20):低VT联合低PEEP通气组(A组)、高VT通气组(B组)和低VT联合高PEEP通气组(C组).静脉注射咪达唑仑、舒芬太尼、依托咪酯和罗库溴铵麻醉诱导,气管插管后行机械通气,A组VT为6 ml/kg,PEEP为5 cm H2O;B组VT为10 ml/kg,PEEP为0;C组VT为6 ml/kg,PEEP为8 cm H2O,维持PETCO2 35～ 45 mm Hg.静脉输注舒芬太尼、维库溴铵和依托咪酯维持麻醉.于麻醉诱导前(T0)、切皮后10 min(T1)、机械通气1 h(T2)、机械通气2 h(T3)和拔除气管导管后15 min(T4)时采集静脉血样,采用ELISA法测定血清IL-10、IL-8和TNF-α的浓度.术毕时采集动脉血样,进行动脉血气分析.术后1d记录肺部并发症的发生情况.结果 与A组比较,B组T4时血清IL-10浓度升高,T1、T2和T4时血清IL-8浓度升高,T1T4时血清TNF-α浓度升高,PaO2和PaO2/FiO2降低,A-aDO2升高,C组T2～T4时血清IL-10浓度升高,T4时血清IL-8和TNF-α的浓度升高,PaO2/FiO2降低(P＜0.05);与B组比较,C组T1 ～T3时血清TNF-α浓度升高(P＜0.05),血气分析指标差异无统计学意义(P＞0.05).术后仅B组发生肺不张1例.结论 低VT联合低PEEP通气可改善腹腔肿瘤根治术老年患者的氧合,减轻全身炎性反应.     

低潮气量联合低呼气末正压通气用于老年患者单肺通气的临床研究

目的探讨低潮气量(VT)联合低呼气末正压通气(PEEP)对老年患者实施胸科手术单肺通气的临床有效性。方法选择实施胸科手术的老年患者60例。随机均分为研究组和对照组。研究组患者术中采用低VT联合低PEEP;对照组术中采用常规通气方案。记录两组术中PaO2、PaCO2、PETCO2、MAP、CVP及气道峰压(Ppeak)。结果与对照组比较,单肺通气60min时研究组PaO2显著升高,Ppeak明显下降(P<0.05);两组不同时点PaCO2、PETCO2及MAP差异无统计学意义;研究组患者术后3d内有3例术后并发症,明显低于对照组的6例(P<0.05)。结论对于老年患者实施胸科手术采用低VT联合低PEEP通气可有效改善患者术后低氧血症,减少术后肺部并发症,有利于患者术后呼吸功能的恢复,可以安全有效地应用于老年开胸手术。     

不同通气模式对老年患者腹腔镜结直肠手术呼吸参数的影响

目的观察小潮气量容量控制通气(VCV)联合呼气末正压通气(PEEP)和压力控制通气(PCV)联合PEEP对老年患者呼吸参数的影响。方法选择行腹腔镜直肠、乙状结肠手术患者51例,男25例,女26例,年龄65~80岁,BMI 18~30kg/m2,ASAⅠ或Ⅱ级,随机分为两组:VP组(VCV+PEEP)和PP组(PCV+PEEP),每组25例。气腹期间VP组以VT6 ml/kg+5cmH2O PEEP模式通气,PP组将VT设为6 ml/kg通气3 min后切换为PCV并加用5cmH2O PEEP进行通气。记录气管插管VCV通气5min(T1)、建立人工气腹5 min(T2)、建立人工气腹35min(T3)、建立人工气腹65min(T4)、手术结束(T5)、拔管前(T6)时VT、动态肺顺应性(Cdyn)、RR、气道峰压(Ppeak)、气道平台压(Pplat)和PETCO2。记录T1、T3、T4和离开PACU(T7)时PaO2、PaCO2,并计算肺泡-动脉血氧分压差(PA-aDO2)、氧合指数(OI)、呼吸指数(RI);记录术后5d内肺部并发症(PPCs)情况。结果与VP组比较,T2-T4时PP组VT明显升高、Cdyn明显增大(P0.05),T3-T5时PP组RR明显减慢(P0.05),T2-T5时PP组Ppeak和Pplat明显降低(P0.05),T4时PP组PETCO2和PA-aDO2明显降低、PaO2明显升高、RI明显减小、OI明显增大(P0.05)。术后随访两组患者PPCs差异无统计学意义。结论PCV联合PEEP通气模式明显降低Ppeak和Pplat、增高VT和增大Cdyn,同时明显改善气腹65min时肺氧合功能,所以老年患者腹腔镜结直肠手术术中应优先考虑使用。     

小潮气量肺保护性通气策略与压力通气模式对妇科腹腔镜手术患者氧合功能的影响

目的:评价小潮气量肺保护性通气策略(protective lung ventilation mode,PLV)与压力通气模式(pressure con-trolled ventilation,PCV)在妇科腹腔镜手术中应用的有效性及安全性。方法:拟于我院择期行妇科腹腔镜手术的患者共计144例,按随机序列号分为PLV组和PCV组,每组72例。PLV组潮气量6 ml/kg,吸呼比1∶2,呼吸频率16次/min,呼气末正压5 cmH 2O(1 cmH 2O=0.098 kPa);PCV组设定通气压力维持潮气量8 ml/kg,吸呼比1∶2,呼吸频率12~16次/min。分别于气管插管后5 min(T1)、气腹后10 min(T2)、气腹后20 min(T3)、撤除气腹后10 min(T4)记录患者气道峰压(airway peak pressure,Ppeak)、平均气道压(mean airway pressure,Pmean),并计算动态肺顺应性(dynamic lung compliance,Cdyn)。于T3、T4时点行血气分析记录PaO 2、PaCO 2、肺泡-动脉氧分压差(alveoli-arterial oxygen partial pressure,A-aDO 2),并计算氧合指数(oxygenation index,OI)。结果:PLV组T3时点Ppeak、Pmean显著高于PCV组,但Cdyn低于PCV组,差异有统计学意义(P<0.05)。PLV组T4时点Ppeak显著高于PCV组,差异有统计学意义(P<0.05)。两组T2、T3时点Ppeak、Pmean较T1时点显著升高,而Cdyn显著低于T1时点,差异有统计学意义(P<0.05)。PLV组T3时点Ppeak、Pmean显著高于T2时点,Cdyn显著低于T2时点,差异有统计学意义(P<0.05)。PLV组T3时点PaO 2、OI显著高于PCV组,而PaCO 2、A-aDO 2显著低于PCV组,差异有统计学意义(P<0.05)。两组T4时点PaO 2、OI较T3时点显著升高,而PaCO 2、A-aDO 2较T3时点显著降低,差异有统计学意义(P<0.05)。两组T4时点PaO 2、PaCO 2、A-aDO 2、OI差异无统计学意义(P>0.05)。两组间各呼吸系统并发症发生情况及住院天数差异均无统计学意义(P>0.05)。结论:对妇科腹腔镜手术患者而言,PCV有助于维持患者呼吸动力学稳定,而小潮气量PLV有助于维持患者术中氧合功能,二者安全性差异无统计学意义。     

经胸腔镜肺大泡切除术中应用单肺通气对血气及血液动力学的影响

目的　观察胸腔镜手术中单肺通气时应用不同水平的呼气末正压通气 (PEEP)对血气及血液动力学的影响。方法　随机选择胸腔镜肺大泡切除术病人 36例 ,均分为三组 :A组为单肺间歇正压通气 (IPPV)通气 ;B组为单肺IPPV加PEEP 5cmH2 O通气 ;C组为单肺IPPV加PEEP10cmH2 O通气。分别记录平卧位双肺通气、侧卧位双肺通气、单肺通气 10min和 30min四个时点的血气和血液动力学参数。结果　各组病人SpO2 始终维持在 99%～ 10 0 %。动脉血氧分压 (PaO2 )也在正常范围 ,但B、C组明显高于A组 (P <0 .0 5 )。其余血气指标无明显变化。三组病人HR、MAP、左心室射血时间 (LVET)及体循环血管阻力 (SVR)均无明显变化。B、C组在单肺通气 10min及 30min后 ,每搏量 (SV)及心输出量 (CO)下降明显 ,但均在正常范围 ,且无组间差异。体位改变时血液动力学稳定。结论　经胸腔镜肺大泡切除术中单肺IPPV、PEEP 5cmH2 O均能维持满意的PaO2 和动脉血二氧化碳分压 (PaCO2 ) ,血液动力学变化不显著 ;但PEEP 5cmH2 O较IPPV能进一步提高PaO2 ,PEEP 10cmH2 O不能较PEEP 5cmH2 O进一步提高PaO2 。     

麻醉诱导期开始采用肺保护性通气策略对妇科腔镜手术患者氧合及预后的影响

目的探讨从麻醉诱导期开始采用肺保护性通气策略对妇科腔镜手术患者氧合及预后的影响。方法选择在本院接受妇科腹腔镜手术的患者60例,随机分为三组,每组20例。采用间歇正压通气(IPPV)模式,氧浓度为100%,氧气流量2 L/min,吸呼比为1∶2。A组:从诱导期(即自主呼吸消失后,予面罩机械通气5 min)开始全程通气模式:VT6 ml/kg,RR 16次/分,PEEP为5cm H2O,每30分钟给予一次手法肺复张(手控通气,气道压力维持40 cm H2O,持续30 s);B组:诱导期通气模式:VT10 ml/kg,RR 10次/分,插管后通气模式:VT6 ml/kg,RR 16次/分,PEEP 5cm H2O,每30分钟给予一次手法肺复张;C组:全程通气模式均为VT10 ml/kg,RR 10次/分。记录插管前(T0)、气腹后(T1)、手术开始30 min(T2)、60 min(T3)、放气腹(T4)时的气道峰压(Ppeak)、平均气道压(Pmean)、计算肺顺应性(CL),并在T0、T1、T3、清醒拔管后吸空气5 min(T5)时抽取动脉血进行血气分析,计算氧合指数(OI)及肺内分流率(Qs/Qt)。记录患者术后并发症发生情况与住院天数。结果与T0时比较,T1~T4时三组Ppeak和Pmean均明显升高,C组Ppeak明显高于A组和B组(P0.05),T2时C组Pmean明显高于A组和B组(P0.05);三组CL在气腹后明显降低(P0.05),T3和T4时C组明显低于A组和B组(P0.05);三组PETCO2在气腹后明显升高,T2~T4时C组明显低于A组与B组(P0.05),A组与B组差异无统计学意义;三组OI随着时间延长变化差异无统计学意义,拔管后三组均明显降低(P0.05);三组Qs/Qt随着手术进行呈上升趋势,与T0时比较,三组在T3时明显上升(P0.05),C组明显大于A组和B组(P0.05);T5时均明显下降(P0.05)。术后仅C组有1例发生肺部感染。结论与常规通气相比,对接受妇科腔镜手术患者采用保护性肺通气策略能够明显改善患者的肺顺应性和氧合功能,有利于肺保护。     

肥胖患者腹腔镜结直肠癌根治术中实时食管压监测下呼气末正压通气对肺通气的影响

目的探讨实时食管压监测指导下设定呼气末正压(positive end expiratory pressure,PEEP)通气参数对肥胖腹腔镜结直肠癌根治术患者的临床价值。方法选择2016年1—12月收治的拟行腹腔镜结直肠癌根治术的肥胖患者90例,男50例,女40例,年龄40~65岁,BMI30kg/m2,ASAⅡ或Ⅲ级,采用随机数字表法将患者随机分为三组:P组、PEEP5组和PEEP10组,设置VT8ml/kg,分别在肺复张后给予个体化PEEP(采用实时食管压监测通过计算呼气末跨肺压=0cmH_2O和吸气末跨肺压=25cmH_2O确定最佳PEEP)、PEEP 5cmH_2O和10cmH_2O。观察气腹建立前(T0)、气腹建立后10min(T1)、气腹后头低40.5°足高位20 min(T2)和气腹结束(T3)时的呼吸力学指标。结果T1—T3时P组Ppeak、SBP明显低于,PaO_2/FiO_2明显高于PEEP5组和PEEP10组(P0.05);T2时P组Pplat、Raw明显低于PEEP5组(P0.05);T2、T3时P组Cst明显高于PEEP5组(P0.05);T1、T2时P组DBP明显低于PEEP5组和PEEP10组(P0.05)。结论实时食管压监测应用于PEEP通气的肥胖腹腔镜结肠癌手术患者,能够有效改善患者呼吸和循环功能。     

小潮气量加低水平呼气末正压通气对腹腔镜手术患者呼吸力学及肺氧合功能的影响

目的探讨小潮气量加低水平呼气末正压（positive end-expiratory pressure,PEEP）机械通气对肺功能正常患者人工气腹期间呼吸力学及肺氧合功能的影响。方法 2009年8月~2010年4月,45例ASAⅠ~Ⅱ级,择期全麻下行腹腔镜手术患者,随机均分为3组,每组15例。麻醉诱导维持用药相同,气管插管后行机械通气,气腹前3组通气参数均设定为潮气量（VT）8 ml/kg,呼吸频率（RR）12次/min,吸呼比（I∶E）=1∶2。气腹后通气参数设定分别为：Ⅰ组VT=6 ml/kg,RR=18次/min,PEEP=5 cm H2O;Ⅱ组VT=10 ml/kg,RR=10次/min,PEEP=0;Ⅲ组（对照组）同气腹前。分别在气管插管后（T0）,手术开始（T1）,气腹5 min（T2）,气腹30 min（T3）,气腹60 min（T4）,拔气管导管前15 min（T5）,拔气管导管后20 min（T6）监测脉搏血氧饱和度（SpO2）、呼气末CO2分压（PETCO2）、气道峰压（Ppeak）、平均气道压（Pmean）,并计算肺动态顺应性（Cdyn）。分别在T0,T3,T4,T6时点抽取动脉血监测血气,并根据动脉血氧分压（PaO2）、动脉血CO2分压（PaCO2）、吸入氧浓度（FiO2）等计算氧合指数、呼吸指数、肺泡动脉血氧分压差（A-aDO2）。结果 3组各时点平均动脉压及心率、PaO2组间比较差异无显著性（P〉0.05）。与T0时相比,Ppeak气腹后升高（P〈0.05）,Ⅱ、Ⅲ组更明显;Pmean气腹后也升高（P〈0.05）,Ⅰ组最明显;Cdyn气腹后明显降低（P〈0.05）,Ⅱ组最明显;PETCO2明显升高（P〈0.05）,Ⅰ组更明显;气腹后pH值明显降低（P〈0.05）,Ⅰ组最明显;Ⅰ、Ⅲ组PaCO2气腹后明显升高（P〈0.05）,Ⅱ组无明显变化（P〉0.05）。与机械通气时（T0、T3、T4）相比,3组A-aDO2拔管后（T6）明显降低（P〈0.05）,Ⅰ组更明显;氧合指数拔管后（T6）明显降低（P〈0.05）,3组组间差异无显著性（P〉0.05）;呼吸指数拔管后明显降低,Ⅰ组最明显（P〈0.05）。结论小潮气量机械通气加低水平呼气末正压可以有效降低术中气道压,改善肺顺应性,增加肺通气效率,可以安全地应用于腹腔镜手术呼吸管理中。     

压力-容积曲线指导开胸手术患者个体化保护性单肺通气的效果

目的 评价应用动态压力-容积曲线(P-V曲线)设定开胸手术患者个体化的潮气量(VT)和呼气末正压(PEEP)行单肺通气(OLV)的效果.方法 择期行肺叶切除术患者25例,性别不限,年龄44～64岁,体重57～75 kg,ASA分级Ⅰ或Ⅱ级.常规双肺通气30 min后(T0)行OLV,按照动态P-V曲线低位拐点对应的压力(PLIP) +0.196 kPa设定PEEP,根据动态P-V曲线高位拐点对应的容量(VUTP)设定VT,通气30 min后(T1)将VT降至80％ VUIP,通气30 min后(T2)再将VT降至60％ VUIP,然后再通气30 min (T3).OLV期间吸呼比1∶1 ～2,通气频率14～20次/min,维持PETC02 4.67～6.00kPa.分别于T0-3时记录MAP、HR、CVP和气道峰压(Ppeak)、气道阻力(Rsw)、胸肺顺应性(CL),同时采集动脉和中心静脉血样,进行血气分析,记录pH值、PaO2和PaCO2,计算肺内分流率(Qs/Qt).结果 与T0时比较,T1-3时HR、Ppeak、Rsw和Qs/Qt升高,CL和PaO2降低,T1.2时CVP升高,T3时MAP和PaCO2升高(p＜0.05);与T1时比较,T2.3时Ppeak和Rsw降低,T1.2时Pa02升高,Qs/Qt降低,T3时CVP降低,MAP和PaC02升高(P＜0.05).结论 根据80％ VUU确定VT,PuP +0.196 kPa确定PEEP,有助于改善开胸手术患者的氧合,对血液动力学无明显影响,是实现个体化保护性OLV的有效手段.     

Positive pressure versus pressure support ventilation at different levels of PEEP using the ProSeal laryngeal mask airway

We compared positive pressure ventilation with pressure support ventilation at different levels of positive end expiratory pressure (PEEP) using the ProSeal laryngeal mask airway (PLMA). Forty-two anaesthetized adults (ASA 1-2, aged 19 to 63 years) underwent positive pressure ventilation and then pressure support ventilation each with PEEP set at 0, 5 and 10 cmH2O in random order. Pressure support ventilation was with the inspired tidal volume (VTInsp) set at 7 ml/kg and the respiratory rate adjusted to maintain the end-tidal CO2 (ETCO2) at 40 mmHg. Pressure support ventilation was with pressure support set at 5 cmH2O above PEEP and initiated when inspiration produced a 2 cmH2O reduction in airway pressure. Tidal volumes were similar during positive pressure and pressure support ventilation with PEEP, but were higher for the former without PEEP Respiratory rate and peak inspiratory flow rate were higher during pressure support than positive pressure ventilation (all P < 0.001). Peak airway pressure (Ppaw), mean airway pressure (Mpaw), peak expiratory flow rate, and expired airway resistance were lower during pressure support than positive pressure ventilation (all P < 0.001). With PEEP set at 10 cmH2O, ETCO2 was lower for pressure support than positive pressure ventilation. During positive pressure ventilation, there was an increase in Ppaw, Mpaw and dynamic compliance (Cdyn) with increasing levels of PEEP (all P < 0.01). During pressure support ventilation, there was an increase in inspired and expired tidal volume, Ppaw, peak inspiratory and expiratory flow rates and Cdyn, and a reduction in ETCO2, work of breathing, and expired airway resistance with increasing levels of PEEP (all P < 0.01). There were no differences in SpO2, non-invasive mean arterial pressure, heart rate or leak fraction. We conclude that pressure support ventilation provides equally effective gas exchange as positive pressure ventilation during PLMA anaesthesia with or without PEEP at the tested settings. During pressure support, PEEP increases ventilation and reduces work on breathing without increasing leak fraction.     

肥胖患者围手术期通气策略Meta分析

目的 系统评价围手术期不同通气策略对肥胖患者通气和肺功能的影响,选择最佳通气策略. 方法 网上检索EBSCO、PubMed、Spring、Ovid、Wiley、中国知网、维普网、万方数据等数据库,选择全身麻醉诱导期和拔管后的给氧模式以及术中不同潮气量对肥胖患者通气和肺功能影响的随机对照试验(randomized controlled trial,RCT),应用RevMan 5.3软件对纳入文献进行Meta分析. 结果 共纳入24篇RCT,946例患者.①麻醉诱导期头高位吸氧较平卧位吸氧无通气安全时限更长(P＜0.001),而自主呼吸时加用持续正压通气(continues positive airway pressure,CPAP)PaO2水平更高(P=0.005),转为机械通气后间歇正压通气(intermittent positive pressure ventilation,IPPV)+呼气末正压通气(positive end expiratory pressure,PEEP)较单用IPPV无通气安全时限更长(P＜0.001),PaO2更高(P＜0.001).②术中大潮气量比小潮气量通气联合PEEP获得更高的氧合指数(oxygenation index,OI)(P=0.02),但同时大潮气量通气可引起更高的气道压(P＜0.001).③拔管后采用无创正压通气(non-invasive positive pressure ventilation,NIPPV)较鼻导管吸氧PaO2更高(P=0.004). 结论 肥胖患者诱导期宜采用头高位CPAP以及IPPV+PEEP通气,术中采用大潮气量+高PEEP,术后拔管后采用NIPPV.     

Continuous positive airway pressure versus positive end-expiratory pressure in respiratory distress syndrome.

The hemodynamic and respiratory effects of spontaneous ventilation with continuous positive airway pressure (CPAP) and mechanical ventilation with positive end-expiratory pressure (PEEP) were compared in nine patients who had adult respiratory distress syndrome. These patients were capable of maintaining spontaneous ventilation (tidal volume above 300 ml. and PaCO2 below 45 torr). Arterial and mixed venous blood gases, cardiac output, oxygen delivery and consumption, pulmonary artery pressure, and pulmonary wedge pressure were measured in 11 instances, with each patient on 5 or 10 cm. H2O CPAP or PEEP, and in nine instances, with each patient on the ventilator but without PEEP (O PEEP). During CPAP, when compared to PEEP at the same level of end-expiratory pressure, mean PaO2 increased significantly (p less than 0.05) and mean physiological shunt decreased (p less than 0.05). In nine of 11 instances, cardiac output was higher on CPAP than on a corresponding level of PEEP. Thus CPAP was more effective than the same amount of PEEP in improving arterial oxygenation by the lung without adversely affecting cardiac output.     

Effect of mechanical ventilation on cytokine response to intratracheal lipopolysaccharide

BACKGROUND: Mechanical ventilation may cause lung injury through the excitation of an inflammatory response and the release of mediators, such as cytokines. The authors tested the hypothesis that intratracheal lipopolysaccharide amplifies the cytokine response to mechanical ventilation. METHODS: Rat lungs were intratracheally instilled with lipopolysaccharide followed by ex vivo mechanical ventilation for 2 h with low tidal volume of 7 ml/kg with 3 cm H2O positive end-expiratory pressure (PEEP), high tidal volume of 40 ml/kg with zero PEEP, medium tidal volume of 15 ml/kg with 3 cm H2O PEEP, or medium tidal volume and zero PEEP. RESULTS: In the absence of lipopolysaccharide, lung lavage concentrations of tumor necrosis factor and interleukin 1 beta but not macrophage inflammatory protein 2 were significantly higher in lungs ventilated at high tidal volume/zero PEEP than at low tidal volume. There was a marked increase in lavage tumor necrosis factor and macrophage inflammatory protein 2 concentrations in lungs ventilated at low tidal volume after exposure to intratracheal lipopolysaccharide at doses of 100 ng/ml or greater. However, in lungs ventilated at high tidal volume, this response to lipopolysaccharide was markedly reduced. In addition, the number of alveolar macrophages recovered in the lavage was significantly lower in lungs ventilated at high tidal volume. CONCLUSION: Ventilation strategy can modify lung cytokine responses to lipopolysaccharide, likely through an effect on the alveolar macrophage population.     

肺泡复张术和呼气末正压通气对后腹腔镜术后早期呼吸功能的影响

目的探讨肺泡复张术（RM）复合呼气末正压通气（PEEP）是否能有效改善后腹腔镜手术后早期呼吸功能。方法 30例择期后腹腔镜手术患者,随机分为3组行不同的术中通气方式：对照组（n=10）行常规正压通气;PEEP组（n=10）正压通气加呼气末正压（PEEP）4 cmH2O;PEEP＋RM组（n=10）通气方式与PEEP组相同,在气腹结束后立即以30 cmH2O压力维持30s气道正压行肺泡复张术。在气腹前（Baseline）、气腹后10 min（PI 10 min）、气腹后30 min（PI 30 min）、气腹后60 min（PI 60 min）、放气腹后1 min（PD1 min）、拔管后5 min（EX 5 min）、拔管后0.5h（EX 30 min）等7个时点检测记录呼气末CO （2ETCO2）、动脉血气分析并计算动脉与呼气末CO2差值[D（a-e）CO2]、氧合指数（OI）等。结果与对照组相比,PEEP、PEEP＋RM两组在PI 60 min和PD1 min两个时点的Pa CO2显著降低（P〈0.005）。PEEP组与PEEP＋RM组在PI 30 min、PI 60 min和EX 30 min等时点,其D（a-e）CO2均显著低于对照组（P〈0.05）。在EX 5 min和EX 30 min两时点,PEEP＋RM组的OI则显著高于对照组（P〈0.05）;而两时点间Pa-CO2的差值ΔPaCO2在PEEP＋RM组显著高于对照组（P〈0.05）。结论术中使用PEEP可有效减少动脉血和肺泡的CO2分压差,减少肺泡塌陷;肺泡复张术可在拔管后有效加快动脉血CO2分压的下降并改善氧合指数。复合以上两种处理,可有效减轻后腹腔镜术后早期CO2蓄积,促进呼吸功能恢复。     

Effect of Mechanical Ventilation on Cytokine Response to Intratracheal Lipopolysaccharide

Background: Mechanical ventilation may cause lung injury through the excitation of an inflammatory response and the release of mediators, such as cytokines. The authors tested the hypothesis that intratracheal lipopolysaccharide amplifies the cytokine response to mechanical ventilation.

Methods: Rat lungs were intratracheally instilled with lipopolysaccharide followed by ex vivo mechanical ventilation for 2 h with low tidal volume of 7 ml/kg with 3 cm H2O positive end-expiratory pressure (PEEP), high tidal volume of 40 ml/kg with zero PEEP, medium tidal volume of 15 ml/kg with 3 cm H2O PEEP, or medium tidal volume and zero PEEP.

Results: In the absence of lipopolysaccharide, lung lavage concentrations of tumor necrosis factor and interleukin 1[beta] but not macrophage inflammatory protein 2 were significantly higher in lungs ventilated at high tidal volume/zero PEEP than at low tidal volume. There was a marked increase in lavage tumor necrosis factor and macrophage inflammatory protein 2 concentrations in lungs ventilated at low tidal volume after exposure to intratracheal lipopolysaccharide at doses of 100 ng/ml or greater. However, in lungs ventilated at high tidal volume, this response to lipopolysaccharide was markedly reduced. In addition, the number of alveolar macrophages recovered in the lavage was significantly lower in lungs ventilated at high tidal volume.     

The effect of positive end expiratory pressure on the respiratory profile during one-lung ventilation for thoracotomy

Summary In this randomised controlled trial we examined the effects of four different levels of positive end expiratory pressure (PEEP at 0, 5, 8 or 10 cmH(2)O), added to the dependent lung, on respiratory profile and oxygenation during one lung ventilation. Forty-six patients were recruited to receive one of the randomised PEEP levels during one lung ventilation. We did not find significant differences in lung compliance, intra-operative or postoperative oxygenation amongst the four different groups. However, the physiological deadspace to tidal volume ventilation ratio was significantly lower in the 8 cmH(2)O PEEP group compared with the other levels of PEEP (p < 0.0001). We concluded that the use of PEEP (< or =10 cmH(2)O) during one lung ventilation does not clinically improve lung compliance, intra-operative or postoperative oxygenation despite a statistically significant reduction in the physiological deadspace to tidal volume ratio.     

胸科手术中单肺通气期间不同通气方式的比较

目的 观察胸科手术病人麻醉中单肺通气（ＯＬＶ）期间不同通气方式的效果。方法 １０例择期胸科手术成年病人,ＡＳＡⅠ～Ⅱ级,在ＯＬＶ期间首先采用全潮气量（１０ｍｌ／ｋｇ）不加ＰＥＥＰ,随后采用半潮气量（５ｍｌ／ｋｇ）同时施加７ｃｍＨ２Ｏ ＰＥＥＰ两种通气方式,保持每分通气量不变。在开胸后ＯＬＶ前,ＯＬＶ时采用敏种通气方式后３０ｍｉｎ,以及恢复双肺通气（ＴＬＶ）后３０ｍｉｎ分别进行血气分析,同时监测气道     

"Best" PEEP during one-lung ventilation

Eight patients were studied under general anaesthesia for elective pulmonary lobectomy to see if intrinsic positive end-expired pressure (PEEPi) would appear or increase in the dependent lung during one-lung ventilation (OLV) or if application of external PEEP equal to individually measured PEEPi would produce better arterial oxygenation, haemodynamic state and oxygen delivery than either zero PEEP (ZEEP) or an external PEEP 5 cm H2O greater than PEEPi. Patients were non-obese, without obstructive airways disease, aged 53-76 yr and ASA < III. They received standardized anaesthesia with fentanyl, 50% nitrous oxide in oxygen and isoflurane; monitoring included radial and fibreoptic pulmonary arterial catheters and intermittent positive pressure ventilation with a tidal volume of 8 ml kg-1, 16 bpm, and an I:E ratio of 1:2. PEEPi was measured during two-lung ventilation (TLV) and OLV, using rapid airway occlusion at end-expiration. There was no PEEPi during TLV, but 2-6 mm Hg of PEEPi appeared during OLV. Applying external PEEP equal to individually measured PEEPi reduced venous admixture and increased PaO2 without a decrease in cardiac index (thus increasing oxygen delivery) compared with ZEEP, but the improvement in pulmonary gas exchange was lost and an additional penalty of reduced cardiac output was imposed when external PEEP was increased to 5 mm Hg above PEEPi.      

Differential Lung Ventilation with Unilateral PEEP Following Unilateral Hydrochloric Acid Aspiration in the Dog

Differential lung ventilation with positive end expiratory pressure (PEEP) improves pulmonary gas exchange when used in the supportive care of patients with severe unilateral or asymmetrical lung disease. Once the provision of selective PEEP to the two lungs is accomplished, the best method of partitioning the tidal volume between the two lungs is unknown. Twelve mongrel dogs were given a unilateral hydrochloric acid (HCl) aspiration injury. A computer controlled differential lung ventilation system was used to ventilate four dogs with equal volumes to each lung, four dogs with equal driving pressure (end inspiratory pressure-PEEP) to each lung, and four dogs with equal end-tidal CO₂ fraction from each lung. The respiratory rate was feedback controlled to maintain Paco₂ at 4.67 kPa. The dogs were kept supine and ventilated with 30% O₂. Following injury, the PEEP was set at 0 kPa for 1 h. The dogs were then given 1.36 kPa and 2.72 kPa PEEP to the injured lung for 2 h in a cross-over fashion. The assignment of the tidal volume controller, the side of injury, and the PEEP sequence was random. Oxygen tension fell and pulmonary venous admixture increased after giving the HCl injury. In all three groups considered simultaneously, unilateral PEEP improved Pao₂ and venous admixture. The equal tidal volume distribution was the only group to show a significant improvement in Pao₂ at both PEEP increments (0 to 1.36 kPa and 2.72 kPa). There was a significant difference in tidal volume allocation between the three groups with the equal end-tidal and equal pause pressure groups only minimally ventilating the injured lung. With differential lung ventilation and unilateral PEEP, equal partitioning of tidal volume provides the highest Pao₂, compared to the other two methods of partitioning tidal volume.