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。     

呼气末正压通气对腹腔镜宫颈癌根治术患者眼压和视神经鞘直径的影响

目的观察腹腔镜下宫颈癌根治术中,5 cmH_2O的呼气末正压通气(PEEP)对患者眼内压(IOP)和颅内压的影响。方法选择我院择期行腹腔镜下宫颈癌根治术的患者60例,年龄45～65岁,BMI 20～25 kg/m~2,ASAⅠ或Ⅱ级。采用随机数字表法分为两组,PEEP为5 cmH_2O组(PEEP组)和无PEEP组(ZEEP组),每组30例。两组均采用静脉麻醉诱导气管插管,诱导完成机械通气后,PEEP组设置呼气末正压为5 cmH_2O,ZEEP组呼气末正压设置为0。记录麻醉诱导前(T_0)、麻醉后气腹前10 min平卧位(T_1)、气腹Trendelenburg体位后5 min(T_2)、30 min(T_3)、恢复平卧位气腹消失后(T_4)和术后30 min(T_5)时的IOP、视神经鞘直径(ONSD)、PaO_2、PaCO_2,同时记录T_1—T_4时肺动态顺应性(Cdyn)、气道峰压(Ppeek)和T_0—T_5时HR和MAP。结果与T_0时比较,T_1时两组IOP明显降低(P0.01),T_2—T_3时IOP明显延长(P0.01),T_2—T_3时ZEEP组ONSD明显延长(P0.01),T_3时PEEP组ONSD明显延长(P0.05)。T_1—T_4时PEEP组PaO_2、Cdyn明显高于ZEEP组(P0.05)。T_1时PEEP组Ppeek明显高于ZEEP组(P0.05)。结论在腹腔镜宫颈癌根治术手术中,气腹和Trendelenburg体位下应用5 cmH_2O的PEEP改善患者氧合的同时不引起IOP和颅内压的增高。     

不同通气模式在腹腔镜妇科手术肥胖患者中的应用效果评价

目的探讨压力控制通气(Pressure-controlled ventilation,PCV)与容量控制通气(Volume-controlled ventilation,VCV)对腹腔镜妇科手术肥胖患者呼吸功能及血气分析相关指标的影响。方法选取本院2014年1月至2017年6月择期于腹腔镜下行妇科手术的肥胖患者共计80例。ASA分级Ⅰ~Ⅱ级,体重指数(Body Mass Index,BMI)30kg/m2。患者采用计算机随机软件分为PCV与VCV每组各40例。于气管插管后10分钟(T_0)、气腹后10分钟(T_1)、气腹后30分钟(T_2)、撤除气腹后10分钟(T_3)记录患者气道平台压(Pplat)、气道峰压(Ppeak)、平均气道压(Pmean)、动态肺顺应性(Cdyn)。于上述各时点抽取动脉血行血气分析并记录PaO_2、PaCO_2、PH值。观察术后24小时内气胸、皮下气肿、肺水肿发生情况。结果在T_1、T_2时点,PCV组患者Pplat、Ppeak、Pmean显著低于VCV组患者,PCV组患者Cdyn显著高于VCV组,差异有统计学意义(P0.05);PCV组患者PaO_2显著高于VCV组患者,PCV组患者PaCO_2显著低于VCV组,差异有统计学意义(P0.05)。两组患者PH值在各时点差异均无统计学意义(P0.05)。所有患者均未发生气胸、皮下气肿、肺水肿等并发症。结论对行妇科腹腔镜手术的肥胖患者而言,PCV能够在气腹期间维持较低的气道压力及较高的肺顺应性,同时还能维持较高的PaO_2及较低的PaCO_2,与VCV相比具有良好的安全性和有效性。     

肥胖患者行腹腔镜手术3种通气模式的比较

目的观察肥胖患者行全麻腹腔镜手术时,不同的机械通气模式对病人氧合情况的影响。方法选择60例行腹部腹腔镜手术的肥胖患者,按手术日期分为3组:容量控制通气(volume control ventilation,VCV)组,压力控制通气(pressure control ventilation,PCV)组,压力控制通气联合呼气末正压通气(pressure control ventilation and positive end expiratorypressure,PCV+PEEP)组,每组20例。分别于手术开始气腹后30min(T1)、气腹后60min(T2)、手术结束后拔气管插管后30min(T3)、拔气管插管后60min(T4),采血测定pH、PCO2、氧合指数、肺内分流率。结果PCV+PEEP组T1时点氧合指数429.35±51.88显著高于VCV组346.15±54.48(q=6.771,P<0.05)和PCV组393.50±58.34(q=2.918,P<0.05),T4时点氧合指数231.87±20.47显著高于VCV组211.50±12.52(q=5.172,P<0.05)和PCV组220.12±18.84(q=2.983,P<0.05)。PCV+PEEP组T1、T2、T3、T4的肺内分流率分别为(10.94±1.40)%、(11.17±1.42)%、(10.24±1.22)%、(9.92±1.09)%显著低于VCV组(12.09±1.41)%、(12.67±1.76)%、(11.64±1.44)%、(11.34±1.38)%(q=3.771,P<0·05;q=4.772,P<0.05;q=4.872,P<0.05;q=4.772,P<0.05)。HR、MAP3组不同时点比较无明显差异(P>0·05)。结论行腹腔镜手术时,压力控制通气联合呼气末正压通气可以显著提高肥胖患者的氧合情况。     

不同通气模式对腹腔镜下Trendelenburg体位患者肺通气的影响

目的 采用电阻抗断层成像(EIT)技术观察容量控制通气(VCV)和压力控制容量保证通气(PCV-VG)模式对腹腔镜下Trendelenburg体位患者全麻术中肺通气的影响。方法 择期全麻下行腹腔镜下Trendelenburg体位妇科手术患者60例,年龄40～65岁,BMI 18～30 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表法将患者分为两组：VCV模式组（V组）和PCV-VG模式组（P组）,每组30例。V组术中采用VCV模式,P组采用PCV-VG模式。记录入室后(T0)、插管后5 min(T1)、更改体位（由平卧位更改为Trendelenburg体位）后即刻(T2)、更改体位后30 min(T3)、更改体位后60 min(T4)、更改体位后120 min(T5)、改平卧位(T6)时的MAP、HR、通气中心(CoV)、依赖静止区(DSS)、非依赖静止区(NSS)的面积百分比。记录T1、T3—T5时气道峰压（Ppeak）、pH、PaO₂、PaCO₂、氧合指数（OI）。记录术后7 d内肺部感染、呼吸衰竭等肺部并发症发生情况。结果 T0—T6时两组MAP、HR差异无统计学意义。与V组比较,T3—T6时CoV面积百分比明显升高,DSS面积百分比明显降低（P<0.05）,T3—T5时Ppeak明显降低（P<0.05）,T4、T5时PaO₂、OI明显升高（P<0.05）。两组术后7 d内均无肺部并发症。结论 PCV-VG通气模式可明显改善腹腔镜下Trendelenburg体位患者术中肺通气及肺氧合功能。     

压力和容量通气模式对肥胖患者腹腔镜手术中呼吸功能的影响

目的 观察肥胖患者行妇科腹腔镜手术时,两种不同的机械通气模式对患者血流动力学、呼吸力学、动脉氧合的影响. 方法 选择40例行妇科腹腔镜手术的肥胖患者,按数字表法随机分为压力控制通气组(pressure-controlled ventilation,PCV)和容量控制通气组(volume-controlled yentilation,VCV),每组20例.两组患者均实施全凭静脉麻醉方案,分别采用不同的通气模式,维持呼气末二氧化碳分压(end-tial carbon dioxide partial pressure,PETCO2)在35 mm Hg～45 mm Hg(1 mm Hg=0.133kPa)之间.分别于麻醉前5 min(T0)、气腹开始前5 min(T1)、气腹后30min(T2)、气腹解除后5 min(T3)、拔除气管导管时(T4),采集动脉血行血气分析,监测和计算血流动力学指标、血气分析指标、呼吸力学指标. 结果 ①在T1、T2、T3 PCV组的PaO2、氧合指数(oxygenation index,OI)(分别为460±78、453±83、463±95)均高于VCV组(P<0.05);PCV组的肺泡动脉血氧分压差(A-aDO2)(分别为74±25、80±30、82±26)、呼吸指数(respiratory index,RI)(分别为0.32±0.08、0.33±0.10、0.34±0.13)明显低于VCV组(P<0.05).②与T0比较,两组在T2、T3、T4 PaCO2明显升高、pH值明显下降(P<0.05);与VCV组比较,PCV组在各时点差异无统计学意义.③与VCV组比较,PCV组在T2气道峰压Ppeak(27.8±1.6)较低(P<0.05). 结论 PCV在肥胖患者的妇科腹腔镜手术麻醉中改善通气与血流比例,促进气体交换.     

压力控制容量保证通气模式对肺切除术患者术后肺部并发症的影响

目的观察压力控制容量保证(PCV-VG)通气模式对肺切除术患者术后肺部并发症(PPCs)的影响。方法选择择期全麻下行胸腔镜肺切除术患者42例,男19例,女23例,年龄18～65岁,ASAⅠ或Ⅱ级。将患者随机分为两组:自双肺通气开始至手术结束始终使用PCV-VG模式通气组(P组)和始终使用容量控制通气(VCV)模式通气组(V组),每组21例。P组双肺通气期间V_T 8 ml/kg,单肺通气(OLV)期间V_T 6 ml/kg,压力上升时间设置为0.5 s; V组双肺通气期间设置V_T 8 ml/kg, OLV期间设置V_T 6 ml/kg,吸气暂停时间为0 s。记录术后1、2、3 d和出院前PPCs的发生情况。记录OLV前(T_0)、OLV 30 min(T_1)、OLV 60 min(T_2)和OLV结束后(T_3)的吸气峰压(PIP)、驱动压(ΔP)、动态肺顺应性(Cdyn)以及PaO_2、PaCO_2和氧合指数(PaO_2/FiO_2)。结果术后1 d P组PPCs发生率明显低于V组[2例(9%) vs 8例(38%),P0.05]。术后2、3 d和出院前两组PPCs发生率差异无统计学意义。T_0—T_3时P组PIP明显低于V组(P0.05)。与T_0时比较,T_1、T_2时两组PIP和ΔP明显升高(P0.05),Cdyn明显降低(P0.05)。T_0—T_3时两组ΔP、Cdyn、PaO_2、PaCO_2和PaO_2/FiO_2差异无统计学意义。结论 PCV-VG模式优于VCV模式,可明显减少肺切除患者术后1 d肺部并发症的发生,降低术中吸气峰压。     

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。     

呼气末正压通气对腹腔热灌注化疗患者呼吸力学及肺功能的影响

目的探讨不同呼气末正压通气对腹腔热灌注化疗患者呼吸力学及肺功能的影响。方法选择择期行腹膜癌热灌注化疗的患者90例,男55例,女35例,年龄40~70岁,ASAⅠ~Ⅲ级。随机分为三组,每组30例。A组为容量控制通气(VCV)组,VT10 ml/kg;B组为VCV+低PEEP组,VT6ml/kg,PEEP 5cm H_2O;C组为VCV+高PEEP组,VT6ml/kg,PEEP 10cm H_2O;术中调整RR维持PETCO2 35~45 mm Hg。于气管插管后5 min(T_1)、腹腔热灌注化疗开始前(T2)、化疗结束时(T_3)、气管拔管前(T4)记录气道峰压(Ppeak)、气道平台压(Pplat)和平均气道压(Pmean),计算动态肺顺应性(C_(dyn))。并取桡动脉血进行血气分析,计算氧合指数(OI)、呼吸指数(RI)、肺泡-动脉血氧分压差(A-aDO_2)及死腔率(VD/VT)。记录术后7d内肺部相关并发症情况。结果与A组比较,T_1~T_4时B、C组Ppeak、Pplat、A-aDO_2和RI明显降低,OI和VD/VT明显升高(P0.05);T_2~T_4时B、C组Pmean明显降低,Cdyn和PaO_2明显升高(P0.05)。与T_1比较,T_2~T_4时A组Ppeak、Pplat和Pmean明显升高,C_(dyn)明显降低(P0.05);T_3时B组Ppeak和Pplat明显升高(P0.05),T_2~T_4 Pmean明显升高(P0.05),T3、T4时C_(dyn)明显降低(P0.05);T_2~T_4时C组Ppeak、Pplat和Pmean明显升高(P0.05),T_3、T_4时Cdyn明显降低(P0.05)。与T0时比较,T2~T4时三组PaO_2和OI明显降低,A-aDO_2、RI和VD/VT明显升高(P0.05)。术后7d内B、C组肺部感染、低氧血症和肺不张的发生率明显低于A组(P0.05)。结论小潮气量(6ml/kg)联合PEEP(5cm H_2O)通气可以显著改善腹膜癌患者术中热灌注期间肺功能,降低围术期肺部并发症的发生风险。     

不同机械通气模式对老年腹部手术患者细胞因子的影响

目的探讨不同机械通气模式对于老年腹部手术患者细胞因子的影响。方法 72例择期进行腹部手术全麻机械通气的老年患者(年龄65岁)分为6组,每组12例。A组:VCV(Vt 6 m L/kg)+PEEP 8 mm Hg+auto-flow模式;B组:VCV(Vt 6 m L/kg)+PEEP 8 mm Hg+const-flow模式;C组:VCV(Vt 6 m L/kg)+PEEP 12 mm Hg+auto-flow模式;D组:VCV(Vt 6 m L/kg)+PEEP 12mm Hg+const-flow模式;E组:VCV(Vt 10 m L/kg)+auto-flow模式;F组:VCV(Vt 10 m L/kg)+const-flow模式。6组患者全身麻醉气管插管后,均予以VCV(Vt 6 m L/kg)+const-flow模式通气60 min,再按分组的通气模式进行通气,总通气时间大于5 h。在通气1 h及5 h两个时间点,抽取静脉血和支气管肺泡灌洗液检测IL-8、IL-10、MMP-9、SP-A以及SF浓度。结果大潮气量组(E、F两组)较小潮气量四组(A、B、C、D四组)通气5 h后,血与BALF中测定的IL-8、MMP-9浓度以及血中测定的SP-A、SF浓度明显升高(P0.05),血与BALF中测定的IL-10浓度以及BALF中测定的SP-A浓度明显降低(P0.05)。通气5 h后F组较E组,血及BALF中IL-8以及MMP-9、血SF、血SP-A更高(P0.05),而BALF中SP-A则更低(P0.05)。结论 (1)大潮气量机械通气较小潮气量机械通气而言,更有利于促进IL-8、MMP-9、SF的分泌,抑制IL-10的释放,BALF中SP-A下降,血中SP-A升高,进一步加剧了VILI的程度。(2)就老年(年龄65岁)腹部手术患者而言,围手术期以VCV(Vt6 m L/kg)+PEEP 12 mm Hg+auto-flow模式机械通气较其他五种通气模式,更有利于减轻肺组织急性炎症反应及氧化应激反应的激活,减轻机械通气所致生物伤,从而减轻VILI的程度。     

Comparação entre ventilação garantida por volume controlado por pressão e ventilação controlada por volume em pacientes obesos durante cirurgia laparoscópica ginecológica na posição de Trendelenburg

Background and objectivesThe aim of this study was to investigate the efficacy of the pressure‐controlled, volume‐guaranteed (PCV‐VG) and volume‐controlled ventilation (VCV) modes for maintaining adequate airway pressures, lung compliance and oxygenation in obese patients undergoing laparoscopic hysterectomy in the Trendelenburg position.MethodsPatients (104) who underwent laparoscopic gynecologic surgery with a body mass index between 30 and 40 kg.m^-2 were randomized to receive either VCV or PCV‐VG ventilation. The tidal volume was set at 8 mL.kg^-1, with an inspired oxygen concentration of 0.4 with a Positive End‐Expiratory Pressure (PEEP) of 5 mmHg. The peak inspiratory pressure, mean inspiratory pressure, plateau pressure, driving pressure, dynamic compliance, respiratory rate, exhaled tidal volume, etCO₂, arterial blood gas analysis, heart rate and mean arterial pressure at 5 minutes after induction of anesthesia in the and at 5, 30 and 60 minutes, respectively, after pneumoperitoneum in the Trendelenburg position were recorded.ResultsThe PCV‐VG group had significantly decreased peak inspiratory pressure, mean inspiratory pressur, plateau pressure, driving pressure and increased dynamic compliance compared to the VCV group. Mean PaO₂ levels were significantly higher in the PCV‐VG group than in the VCV group at every time point after pneumoperitoneum in the Trendelenburg position.ConclusionsThe PCV‐VG mode of ventilation limited the peak inspiratory pressure, decreased the driving pressure and increased the dynamic compliance compared to VCV in obese patients undergoing laparoscopic hysterectomy. PCV‐VG may be a preferable modality to prevent barotrauma during laparoscopic surgeries in obese patients.     

低潮气量联合不同阶段呼气末正压通气对老年患者开腹术后肺功能的影响

目的观察术中低潮气量联合不同阶段呼气末正压通气(positive end expiratory pressure,PEEP)对老年患者开腹术后肺功能及并发症的影响。方法选择择期全麻下行开腹手术的老年患者60例,男21例,女39例,年龄≥65岁,ASAⅠ或Ⅱ级,随机分为三组,每组20例。A组手术开始后1h联合PEEP 10cm H_2O持续1h,B组术毕拔除气管导管前1h联合PEEP 10cm H_2O持续1h,C组手术全程联合PEEP 10cm H_2O。分别于术前、术后1、24h行血气分析测PaCO_2、PaO_2和A-aDO_2,计算氧合指数。记录术前、术后24、72h的气道分泌物评分。结果与术前比较,术后1h三组PaCO_2明显升高,B组PaO_2明显下降,A组A-aDO_2明显升高(P0.05);术后24hB组、C组PaCO_2明显升高,B组氧合指数明显下降(P0.05)。与术后1h比较,术后24hA组PaCO_2明显下降,A组A-aDO_2明显下降(P0.05)。术后三组气道分泌物评分差异无统计学意义。结论术中低潮气量联合不同阶段PEEP能够改善术后肺的氧合功能,但对术后肺部并发症无明显影响。     

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。     

Comparison of volume-controlled and pressure-controlled ventilation in steep Trendelenburg position for robot-assisted laparoscopic radical prostatectomy

Study Objective

To compare the effects of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) on respiratory mechanics and hemodynamics in steep Trendelenburg position.

Design

Prospective, randomized clinical trial.

Setting

University hospital.

Patients

34 ASA physical status 1 and 2 patients undergoing RLRP.

Interventions

Patients were randomly allocated to either the VCV (n = 17) or the PCV group (n = 17). After induction of anesthesia, each patient's lungs were ventilated in constant-flow VCV mode with 50% O₂ and tidal volume of 8 mL/kg; a pulmonary artery catheter was then inserted. After establishment of 30° Trendelenburg position and pneumoperitoneum, VCV mode was switched to PCV mode in the PCV group.

Measurements

Respiratory and hemodynamic variables were measured at baseline supine position (T1), post-Trendelenburg and pneumoperitoneum 60 minutes (T2) and 120 minutes (T3), and return to baseline after skin closure (T4).

Main Results

The PCV group had lower peak airway pressure (AP_peak) and greater dynamic compliance (C_dyn) than the VCV group at T2 and T3 (P < 0.05). However, no other variables differed between the groups. Pulmonary arterial pressure and central venous pressure increased at T2 and T3 (P < 0.05). Cardiac output and right ventricular ejection fraction were unchanged in both groups.

Conclusions

PCV offered greater C_dyn and lower AP_peak than VCV, but no advantages over VCV in respiratory mechanics or hemodynamics.     

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。     

The effect of timing of application of positive end-expiratory pressure on oxygenation during one-lung ventilation

Many studies have confirmed that applying positive end-expiratory pressure (PEEP) to the dependent lung during one-lung ventilation (OLV) improves oxygenation. Our purpose was to investigate the best time and level of PEEP application. Thirty patients undergoing thoracic surgery were randomised into three groups. After 20 minutes of two-lung ventilation (TLV) in the lateral position, all patients received OLV for one hour During OLV, 0, 5, 10 cmH2O PEEP were applied in order in group A, with each level sustained for 20 minutes. Group B had 5 cmH2O PEEP applied and maintained for one hour Patients in group C received PEEP with levels set in the opposite order to that of group A. The ventilation model was then converted to TLV. PaO2, PaCO2 and respiratory mechanical variables were compared at five different time points among groups, 20 minutes after TLV (T1), 20 (T2), 40 (T3) and 60 minutes (T4) after OLV and 20 minutes after conversion to TLV (T5). We found that PaO2 was lower in group A than the other two groups at T2 (P <0.05). PaO2 decreased significantly at T5 compared with T1 (P <0.05) in group A only. When PEEP was set to 10 cmH2O, the airway pressure increased significantly (P <0.05). These findings indicate that PEEP applied at the initial time of OLV improves oxygenation most beneficially. Five cmH2O PEEP may produce this beneficial effect without the increase in airway pressure associated with 10 cmH2O PEEP.     

Effects of positive end-expiratory pressure on ventilatory and oxygenation parameters during pressure-controlled one-lung ventilation

OBJECTIVES: The purpose of this study was to investigate the effects of PEEP on oxygenation and airway pressures during PCV-OLV. DESIGN: Randomized, crossover, clinical study. SETTING: University hospital. PARTICIPANTS: Twenty-five patients undergoing thoracotomy. INTERVENTIONS: During the first 5 minutes of OLV, all patients were ventilated with VCV (PEEP: 0) (VCV-ZEEP). Afterward, ventilation was changed to PCV with PEEP: 0 (PCV-ZEEP) or PEEP: 4 cmH2O (PCV-PEEP) for 20 minutes. In the following 20 minutes, PCV-PEEP and PCV-ZEEP were applied in reverse sequence. MEASUREMENTS AND MAIN RESULTS: At the end of VCV-ZEEP airway pressures (peak airway pressure, plateau airway pressure, mean airway pressure, and pause airway pressure) were recorded. At the end of PCV-PEEP and PCV-ZEEP airway pressures, PaO2 and Qs/Qt were recorded. Ppeak and Pplat were significantly lower with PCV-PEEP compared with VCV-ZEEP (eg, Ppeak: 33.4+/-4.2, 28.3+/-4.1, and 28.9+/-3.7 cmH2O in VCV-ZEEP, PCV-ZEEP, and PCV-PEEP, respectively; p<0.05 for PCV-ZEEP v VCV-ZEEP and PCV-PEEP v VCV-ZEEP). PCV-PEEP was associated with an increased PaO2 (230.3+/-69.8 v 189.0+/-54.8 mmHg, p<0.05) and decreased Qs/Qt (33.4%+/-7.3% v 38.4%+/-5.7%, p<0.05) compared with PCV-ZEEP (mean+/-SD). Eighty-eight percent of the patients have benefited from PEEP. CONCLUSION: During OLV, PCV with a low level of PEEP leads to improved oxygenation with lower airway pressures.     

PCV-VG和VCV模式对Trendelenburg体位下腹腔镜手术通气功能的影响研究

目的 研究在Trendelenburg体位下腹腔镜手术中,压力控制容量保证通气（PCV-Vg）和容量控制通气（VCV）对气道压力和呼吸循环指标的影响。方法 40例在头低脚高位行择期腹腔镜手术的ASAⅠ级和Ⅱ级的患者。采用随机数字表法分为VCV组（n=20）和PCV-VG组（n=20）。麻醉诱导后,两种通气方式下,目标潮气量（VT）为8 mL/kg。计算峰值和平均吸气压力、动态顺应性、呼气VT、氧合指数和生理无效腔,仰卧位下麻醉诱导后5 min T1处记录,气腹稳定后5 min为T2,气腹30°头低脚高位后的15 min和60 min分别记为T3和T4。结果 PCV-VG组吸气峰压明显低于VCV组,动态顺应性明显高于VCV组。结论 在Trendelenburg体位下腹腔镜手术的患者中,PCV-VG能够提供比VCV更低的峰值吸气压力和更大的动态顺应性,对肺通气可能有一定的保护作用。