支气管封堵器与双腔支气管导管对开胸前肺萎陷影响的比较

目的 比较支气管封堵器（BB）与双腔支气管导管（DLT）对开胸前肺萎陷效果的影响。方法 选取择期行电视胸腔镜下左肺叶切除术的患者72例,采用随机数表法分为3组（n = 24）：DLT常规萎陷组（DLT组）、DLT开胸前肺萎陷技术组（PTLCT-DLT组）和BB开胸前肺萎陷技术组（PTLCT-BB组）。其中,PTLCT-DLT组和PTLCT-BB组中分别有2例和1例发生低氧血症［经皮动脉血氧饱和度（SpO₂） < 90%］,被剔除,最终DLT组24例、PTLCT-DLT组22例、PTLCT-BB组23例完成该项研究。DLT组右侧卧位前左通道被夹闭并向空气开放,PTLCT-DLT组双肺纯氧通气并在侧卧位前夹闭左通道,PTLCT-BB组在侧卧位前封堵左支气管,排气管被故意堵塞。比较3组患者侧卧位即时（T₁）、单肺通气8 min（T₂）、单肺通气10 min（T₃）和开胸后2 min（T₄）的心率（HR）、收缩压（SBP）、舒张压（DBP）、SpO₂和动脉血氧分压（PaO₂）,记录3组患者在胸腔镜置入即刻的肺萎陷评分（LCS）。结果 与DLT组比较,PTLCT-DLT组和PTLCT-BB组的LCS明显升高（P < 0.05）,PTLCT-DLT组与PTLCT-BB组比较,差异无统计学意义（P > 0.05）。在T₃时点,PTLCT-DLT组和PTLCT-BB组SpO₂较DLT组明显降低（P < 0.05）,PTLCT-DLT组和PTLCT-BB组在T₂和T₃时点PaO₂较DLT组明显降低（P < 0.05）,在T₄时点较DLT组明显升高（P < 0.05）。结论 开胸前肺萎陷技术有助于BB和DLT完成开胸前肺萎陷,两者对开胸前肺萎陷的影响无差异。     

右美托咪定联合酮咯酸氨丁三醇麻醉在腹腔镜胆囊切除术中的应用效果分析

目的 分析右美托咪定与酮咯酸氨丁三醇联合应用于腹腔镜胆囊切除术（LC）的麻醉效果。方法 选取2018年1月－2020年1月该院行LC的患者120例,随机分为对照组（60例）和观察组（60例）。手术过程中,对照组给予酮咯酸氨丁三醇超前镇痛,观察组给予右美托咪定联合酮咯酸氨丁三醇超前镇痛。比较两组患者不同时间点心率（HR）、平均动脉压（MAP）、镇痛评分、镇静评分、氧化应激情况及不良反应。结果 切胆时（T₂）,两组患者HR和MAP水平均明显低于术前（T₁）（P < 0.05）,观察组HR和MAP水平明显高于对照组（P < 0.05）;气管拔管时（T₃）,对照组HR和MAP水平明显高于T₁时点（P < 0.05）,观察组HR和MAP水平明显低于对照组（P < 0.05）。术后6 h（T₅）和12 h（T₆）,两组患者Ramsay评分均明显高于术后1 h（T₄）（P < 0.05）;T₄、T₅和T₆时点,观察组Ramsay评分明显高于对照组（P < 0.05）,数字分级评分（NRS）的动态评分明显低于对照组（P < 0.05）。T₅时点,两组患者血清丙二醛（MDA）和超氧化物歧化酶（SOD）水平均明显高于T₁时点（P < 0.05）,总抗氧化能力（T-AOC）水平明显低于T₁时点（P < 0.05）,且观察组SOD和T-AOC水平明显高于对照组（P < 0.05）,MDA水平明显低于对照组（P < 0.05）。两组患者不良反应发生率比较,差异无统计学意义（P = 0.648）。结论 在酮咯酸氨丁三醇基础上辅以右美托咪定超前镇痛,有助于提高镇痛镇静效果,纠正LC患者机体血流动力学紊乱,控制机体氧化应激反应,且安全性较高。     

右美托咪定复合布托啡诺在无痛支气管镜检查中的应用效果

目的 探讨右美托咪定复合布托啡诺在无痛支气管镜检查中的应用效果。方法 选取2021年5月－2022年5月该院呼吸与危重症医学科支气管镜室行电子支气管镜检查的144例肺结节患者作为研究对象。将144例患者分成A组（利多卡因组）、B组（利多卡因+右美托咪定组）、C组（利多卡因+右美托咪定+舒芬太尼组）和D组（利多卡因+右美托咪定+布托啡诺组）,每组36例。该研究为随机对照单盲试验。全部入组患者入室后,予以鼻导管给氧,按分组实施麻醉后,完成支气管镜检查。比较各组入室时（T₀）、麻醉诱导后5 min（T₁）、电子支气管镜通过声门时（T₂）、操作5 min（T₃）、操作结束时（T₄）和出室时（T₅）各时点的心率（HR）、经皮动脉血氧饱和度（SpO₂）和平均动脉压（MAP）,观察并记录各组术中和术后不良反应,待患者清醒后,行患者舒适度和术者操作满意度问卷调查。结果 4组患者全部完成电子支气管镜检查。4组患者T₂和T₃时点与T₀时点HR的差值比较,差异均有统计学意义（H值分别为21.15和19.63,P < 0.05）,Bonferroni检验显示,C组T₂和T₃时点与T₀时点HR的差值与A组和B组比较,差异均有统计学意义（P < 0.05）。4组患者T₂时点与T₀时点SpO₂的差值比较,差异有统计学意义（H = 9.58,P = 0.023）,Bonferroni检验显示,D组T₂时点与T₀时点SpO₂的差值与A组比较,差异有统计学意义（P < 0.05）。4组患者T₂和T₃时点与T₀时点MAP的差值比较,差异均有统计学意义（H值分别为9.65和21.31,P < 0.05）,Bonferroni检验显示,A组T₂时点与T₀时点MAP的差值及D组T₃时点与T₀时点MAP的差值与其他3组比较,差异均有统计学意义（P < 0.05）。D组患者舒适度评分和术者操作满意度评分高于其他3组,差异均有统计学意义（Z值分别为62.77和53.94,P < 0.01）,D组不良反应发生率明显低于其他3组,差异有统计学意义（P < 0.01）。结论 右美托咪定复合布托啡诺麻醉方案用于无痛支气管镜检查,更能达到无痛苦效果,血流动力学更平稳,不易发生呼吸抑制,患者舒适度及术者操作满意度更高,不良反应较少,值得临床推广应用。     

股神经+坐骨+股外侧皮神经阻滞在膝关节骨性关节炎关节镜术中的作用分析

目的 探讨股神经+坐骨+股外侧皮神经阻滞在膝关节骨性关节炎（KOA）关节镜术中的作用。方法 选取2019年5月－2021年10月该院收治的拟行膝关节镜术治疗的KOA患者86例,依据随机数表法分为观察组和对照组,每组43例。对照组行连续硬膜外麻醉,观察组行股神经+坐骨+股外侧皮神经阻滞麻醉。比较两组患者的运动和感觉阻滞起效时间及持续时间,记录并比较两组患者的麻醉效果、麻醉前（T₀）、麻醉后5 min（T₁）、手术10 min（T₂）、手术30 min（T₃）和手术结束时（T₄）的心率（HR）、平均动脉压（MAP）和不良反应总发生率。结果 观察组运动和感觉神经阻滞起效时间较对照组短（P < 0.05）,运动和感觉神经阻滞维持时间较对照组长（P < 0.05）;两组患者HR和MAP在组间、时间和交互方面比较,差异均有统计学意义（P < 0.05）;对照组的HR在T₀时点与T₁时点、T₁时点与T₃时点比较,差异均有统计学意义（P < 0.05）,MAP在T₀时点与T₁、T₂、T₃和T₄时点以及T₁时点与T₃时点比较,差异均有统计学意义（P < 0.05）;观察组患者T₁、T₂、T₃和T₄时点的MAP高于对照组（P < 0.05）;在不良反应方面,观察组发生率较对照组低（P < 0.05）。结论 股神经+坐骨+股外侧皮神经阻滞能够提高患者在KOA关节镜术中的麻醉效果,阻滞效果理想,可维持血流动力学稳定,降低不良反应发生率。值得临床推广应用。     

纳布啡联合右美托咪定预防性镇痛对鼻内镜手术患者血流动力学和术后疼痛的影响

目的 探讨纳布啡联合右美托咪定预防性镇痛对鼻内镜手术患者血流动力学和术后疼痛的影响。方法 选取择期在鼻内镜下行鼻中隔偏曲矫正术的患者60例，随机分为右美托咪定联合纳布啡组（DN组）和右美托咪定组（D组），每组30例。D组于麻醉诱导前15 min给予右美托咪定0.5 μg/kg泵注；DN组于麻醉诱导前15 min给予右美托咪定0.5 μg/kg泵注，同时静脉注射纳布啡0.20 mg/kg。观察麻醉前（T₁）、插管后即刻（T₂）、手术开始时（T₃）、气管导管拔除即刻（T₄）和拔管后5 min（T₅）的平均动脉压（MAP）和心率（HR），记录术中丙泊酚、舒芬太尼和瑞芬太尼用量，以及苏醒和拔管时间，用数字分级评分（NRS）评估拔管后0.5 h（T₆）、4.0 h（T₇）、8.0 h（T₈）和24.0 h（T₉）的疼痛情况，记录补救镇痛率及不良反应发生率。结果 与T₁时点比较，D组T₂～T₅时点MAP明显升高，HR明显加快（P < 0.05），DN组T₂～T₅时点MAP和HR与T₁时点比较，差异无统计学意义（P > 0.05）。DN组T₂～T₅时点MAP明显低于D组，HR明显慢于D组（P < 0.05），T₆～T₉时点NRS明显较D组低（P < 0.05），瑞芬太尼和丙泊酚用量明显较D组少（P < 0.05），补救镇痛率明显较D组低（P < 0.05）。结论 在鼻内镜手术中使用纳布啡联合右美托咪定预防性镇痛，可稳定患者血流动力学，减少术中麻醉药物用量，减轻术后疼痛，对苏醒及拔管时间无明显影响。     

压力支持通气在七氟醚麻醉下小儿腹腔镜胆总管囊肿切除术围手术期中的应用价值

目的 探讨压力支持通气（PSV）在七氟醚麻醉下小儿腹腔镜胆总管囊肿切除术围手术期中的应用价值。方法 选取2017年2月－2019年6月该院接受腹腔镜胆总管囊肿切除术的患儿54例,按随机数表法分为研究组（n = 27）和对照组（n = 27）。两组患儿均于七氟醚麻醉状态下接受腹腔镜胆总管囊肿切除术,术中研究组采取PSV,对照组采取压力控制通气（PCV）。统计两组患儿手术情况、不同时点血流动力学指标、围手术期不良事件和术后并发症发生情况。结果 两组患儿气腹时间、手术时间、动脉血氧分压（PaO₂）和动脉血二氧化碳分压（PaCO₂）比较,差异无统计学意义（P > 0.05）,研究组气管导管拔除时间明显短于对照组,差异有统计学意义（P < 0.05）;两组患儿麻醉诱导前（T₁）～术毕即刻（T₅）组内心率（HR）及平均动脉压（MAP）比较,差异无统计学意义（F_HR = 0.68,P_HR = 0.410;F_MAP = 0.63,P_MAP = 0.427）,两组间HR和MAP比较,差异无统计学意义（F_HR = 0.64,P_HR = 0.424;F_MAP = 0.11,P_MAP = 0.740）;在T₆时点,两组患者HR和MAP水平,差异有统计学意义（t_HR = 4.84,P_HR = 0.028;t_MAP = 4.69,P_MAP = 0.030）;研究组围手术期不良事件发生率为7.41%,明显低于对照组的29.63%,两组患儿比较,差异有统计学意义（P < 0.05）;研究组术后并发症发生率为3.70%,与对照组的11.11%比较,差异无统计学意义（P > 0.05）。结论 在七氟醚麻醉状态下,于小儿腹腔镜胆总管囊肿切除术中采取PSV,可缩短气管导管拔除时间,减少拔管时血压及HR的波动幅度,降低围手术期不良事件发生率,保证了治疗的安全性。值得临床推广应用。     

静脉利多卡因复合丙泊酚镇静在超声胃镜检查中的应用

目的 探索静脉利多卡因复合丙泊酚镇静在超声胃镜检查中的应用效果。方法 选取2020年3月－2020年7月在雅安市人民医院行超声胃镜检查的患者62例,采用随机数表法分为丙泊酚+利多卡因组（L组）和丙泊酚+生理盐水组（P组）,每组31例。L组镇静前静脉推注利多卡因1.0 mg/kg,然后以1.0 mg/（kg·h）持续泵注,P组以相同方式输注等容量生理盐水。两组患者均给予丙泊酚1.5 mg/kg和舒芬太尼0.1 μg/kg,患者改良警觉 / 镇静评分（MOAA/S） > 3分或尝试内镜进镜失败,根据情况每次追加丙泊酚0.5 mg/kg。记录两组患者诱导前（T₁）、诱导后（T₂）、胃镜插入时（T₃）、退镜时（T₄）的心率（HR）、平均动脉压（MAP）与经皮动脉血氧饱和度（SpO₂）,记录丙泊酚诱导剂量、追加剂量和总量、完全苏醒时间、并发症发生率和内镜医师满意度。结果 两组患者在T₂、T₃和T₄时点的HR较T₁时点慢,MAP较T₁时点低（P < 0.05）。L组各时间点HR、MAP和SpO₂与P组比较,差异无统计学意义（P > 0.05）。L组丙泊酚诱导剂量［（100.08±14.69）和（118.07±27.35）mg］、追加剂量［（73.54±36.34）和（127.52±92.24）mg］、总量［（166.04±27.17）和（244.30±95.05）mg］及平均用量［（5.86±2.67）和（7.44±1.80）mg/（kg·h）］均明显少于P组（P < 0.05）。L组完全苏醒时间明显短于P组［（3.24±1.04）和（4.76±0.99）min］（P < 0.05）。L组低血压、低氧血症、丙泊酚注射痛和呛咳发生率均明显低于P组,内镜医师满意度明显高于P组（P < 0.05）。两组患者心动过缓、咽喉部疼痛和腹痛发生率比较,差异均无统计学意义（P > 0.05）。两组患者均无恶心呕吐发生。结论 超声胃镜检查中静脉推注利多卡因可有效减少术中丙泊酚用量,缩短患者苏醒时间,降低术中并发症发生率,提高内镜医师满意度。     

右美托咪定联合综合体温保护对腔镜手术治疗老年恶性肿瘤患者苏醒期质量及免疫功能的影响

目的 探讨右美托咪定联合综合体温保护对腔镜手术治疗老年恶性肿瘤患者苏醒期质量及免疫功能的影响。方法 选择择期行腔镜手术治疗的老年恶性肿瘤患者90例，随机均分为3组：对照组（C组）、体温保护组（T组）和体温保护联合右美托咪定组（T-D组），每组30例。C组常规体温保护，T组和T-D组综合体温保护；T-D组麻醉诱导前10 min泵注右美托咪定0.5 μg/kg。记录3组患者麻醉诱导开始时（T₀）、手术开始30 min（T₁）、60 min（T₂）、90 min（T₃）、120 min（T₄）以及手术结束时（T₅）的鼻咽温度；于T₀、术后2 h（T₆）、24 h（T₇）和48 h（T₈）时抽取静脉血标本，测定T淋巴细胞亚群（CD3⁺、CD4⁺和CD8⁺）和自然杀伤细胞（NK cell）水平；记录患者术中麻醉药物用量及苏醒期质量指标。结果 与T₀比较，C组T₂～T₅时点鼻咽温度均明显降低（P < 0.05）；与C组比较，T组和T-D组T₂～T₅时点鼻咽温度明显升高（P < 0.05）。与T₀时点比较，C组、T组和T-D组T₆、T₇和T₈时点CD3⁺和NK cell活性均明显降低（P < 0.05）；C组在T₆、T₇和T₈时点，T组和T-D组在T₆和T₇时点，CD4⁺活性均明显降低（P < 0.05）。与C组比较，T组和T-D组T₆和T₇时点CD3⁺细胞活性均明显升高（P < 0.05）；T组在T₇时点，T-D组在T₆和T₇时点，CD4⁺细胞活性均明显升高（P < 0.05）；T组在T₇时点，T-D组在T₆、T₇和T₈时点，NK cell活性均明显升高（P < 0.05）。结论 采用体温保护措施联合右美托咪定能够维持老年恶性肿瘤患者的体温稳定，减少围手术期意外低体温（IPH）的发生，并有效提高患者苏醒期质量，减轻免疫抑制程度，加速患者早期恢复。     

免充喉罩与气管内插管用于全身麻醉下经气管镜超声引导针吸活检的临床研究

目的 探讨免充喉罩与气管插管用于全身麻醉下经气管镜超声引导针吸活检（EBUS-TBNA）对患者围手术期血流动力学、气道峰压、麻醉恢复时间及围手术期不良反应的影响。方法 选择全身麻醉下行EBUS-TBNA的患者64例,随机分为喉罩组（L组,n = 32）和气管插管组（T组,n = 32）。观察两组患者麻醉诱导前（T₀）、诱导后插入喉罩/气管导管前（T₁）、诱导后插入喉罩/气管导管后即刻（T₂）、超声支气管镜置入即刻（T₃）、针吸活检时（T₄）、拔管即刻（T₅）和拔管后10 min（T₆）的血流动力力学变化;记录插入免充喉罩/气管插管后（P₁）、活检镜置入后（P₂）和拔出活检镜后（P₃）的气道峰压;记录两组患者呼吸恢复时间、清醒拔管时间、阿片类药物和顺式阿曲库铵使用量;比较两组患者围手术期不良反应发生率。结果 T组T₂和T₅时点收缩压（SBP）、舒张压（DBP）和心率（HR）均明显高于L组,差异有统计学意义（P < 0.05）;在P₂时点,T组气道峰压明显高于L组,差异有统计学意义（P < 0.05）;L组呼吸恢复时间与清醒拔管时间均短于T组,差异有统计学意义（P < 0.05）;T组瑞芬太尼使用量大于L组,差异有统计学意义（P < 0.05）;T组拔管躁动发生率高于L组,差异有统计学意义（P < 0.05）。结论 与气管插管相比,免充喉罩应用于全身麻醉下EBUS-TBNA,可维持血流动力学平稳,缩短麻醉恢复时间,是围手术期较为安全可行的麻醉管理方式。     

控制性低中心静脉压技术对腹腔镜肝切除术患者脑氧饱和度的影响

目的 运用控制性低中心静脉压（CLCVP）技术的腹腔镜肝切除术,会增加患者神经系统并发症的风险,该研究拟评估该类患者术中脑去氧饱和度事件（CDE）的发生率。方法 选择拟行择期腹腔镜肝切除术的患者94例,随机分为CLCVP组（A组）及非CLCVP组（B组）,各47例。两组患者均采用全凭静脉麻醉。分别观察术前（T₀）、麻醉诱导气管插管后5 min（T₁）、患者置于30°头高脚低位后5 min（T₂）、手术切皮后5 min（T₃）、切肝前5 min（T₄）［A组实施CLCVP,中心静脉压（CVP）控制在5 cmH₂O以内;B组维持CVP在正常范围］、切肝结束后5 min（T₅）和术毕（T₆）的血流动力学变化、脑氧饱和度（rSO₂）和升压药使用情况。记录CDE的发生情况、麻醉后监测治疗室（PACU）复苏时间、术后复苏室视觉模拟评分（VAS）≥4分、术后躁动、恶心和呕吐等发生情况。结果 两组患者平均动脉压（MAP）在T₄、T₅和T₆时点较T₀时点更低,且在T₄时点A组MAP下降更明显,两组患者比较,差异有统计学意义（P < 0.05）。两组患者rSO₂在T₄、T₅和T₆时点较T₁时点降低,且A组降低更明显,差异有统计学意义（P < 0.05）。A组CDE发生率较B组高（35.6%和4.3%,P = 0.001）,升压药物使用率较B组高（48.9%和19.6%,P = 0.003）。A组恶心及呕吐发生率较B组高,差异有统计学意义（26.7%和8.7%,P = 0.024）。结论 运用CLCVP技术的腹腔镜肝切除术,较常规腹腔镜肝切除术可明显降低患者术中rSO₂,增加术中CDE发生率。     

单向活瓣通气给氧在机械通气患者撤机中的应用研究

目的探讨在机械通气患者撤机过程中,使用单向活瓣通气给氧的方法对脱机训练的影响。方法选择行机械通气72 h以上患者48例,符合撤机标准,在准备撤机前将患者随机分成观察组和对照组各24例,观察组使用单向活瓣通气给氧的方法对患者进行脱机训练,对照组采用常规氧气管给氧通气的方法,通过观察两组患者的血气分析、呼吸频率、心率、血压变化,并了解患者的耐受性及舒适度改变等指标。结果两组患者在脱机后1 h3、h2、4 h动脉血气分析的血氧分压(PaO2)、动脉血氧饱和度(SaO2)、呼吸次数、心率、血压变化相比较,差异有显著性意义(P<0.05)。观察组患者的耐受性及舒适度明显比对照组好。结论使用单向活瓣通气给氧用于机械通气患者撤机的方法,可以使患者能吸入较精确的足够的氧混合气体,降低导管死腔,减少患者的呼吸做功,增加患者的舒适度,从而能使患者达到快速、顺利脱机的目的。     

胸科手术单肺通气期间定容模式和定压模式的比较

目的比较胸科手术单肺通气（OLV）期间采用定容（VCV）和定压（PCV）两种不同通气模式的效果。方法ASAⅠ～Ⅱ级、年龄18～68岁需行单肺通气胸科手术患者24例，随机分为Ⅰ、Ⅱ两组，每组各12例。全身麻醉诱导插双腔管后，侧卧位行双肺定容通气（TLV-VCV）后Ⅰ组先单肺定容通气（OLV—VCV）30min后行单肺定压通气（OLV—PCV），Ⅱ组单肺通气的顺序与Ⅰ组相反，即先定压通气（OLV—PCV）30min再定容通气（OLV—VCV）。双肺定容通气后，每种单肺通气后30min测定并记录心率（HR）、平均动脉压（MAP）、中心静脉压（CVP）、脉搏氧饱和度（SpO2）、气道峰压（Ppeak）、平均气道压（Pmean）、潮气量（VT）、呼吸末二氧化碳分压（PETCO2）。同时抽动血测血氧分压、氧饱和度（PaO2、SaO2）及二氧化碳分压（PaCO2）。结果患者TLV-VCV，OLV-VCV与OLV-PCV期间的HR、MAP、CVP、SpO2差异无统计学意义（P〉0．05）；OLV-VCV和OLV-PCV的Ppeak和Pmean较TLV-VCV高（P〈0．05或P〈0．01），而OLV—VCV又比OLV-PCV高（P〈0．05或P〈0．01）；OLV．PCV的PaO2较OLV-VCV高（P〈0．01），三种通气的VT、Sa02、PET，CO2、PaCO2差异无统计学意义（P〉0．05）。结论单肺定压通气效果优于单肺定容通气。     

Mouth-to-mouth ventilation is superior to mouth-to-pocket mask and bag-valve-mask ventilation during lifeguard CPR: a randomized study

Aim

The quality of cardiopulmonary resuscitation (CPR) is a crucial determinant of outcome following cardiac arrest. Interruptions in chest compressions are detrimental. We aimed to compare the effect of mouth-to-mouth ventilation (MMV), mouth-to-pocket mask ventilation (MPV) and bag-valve-mask ventilation (BMV) on the quality of CPR.

Materials and methods

Surf lifeguards in active service were included in the study. Each surf lifeguard was randomized to perform three sessions of single-rescuer CPR using each of the three ventilation techniques (MMV, MPV and BMV) separated by 5 min of rest. Data were obtained from a resuscitation manikin and video recordings.

Results

A total of 60 surf lifeguards were included (67% male, 33% female, mean age 25 years). Interruptions in chest compressions were significantly reduced by MMV (8.9 ± 1.6 s) when compared to MPV (10.7 ± 3.0 s, P < 0.001) and BMV (12.5 ± 3.5 s, P < 0.001). Significantly more effective ventilations (visible chest rise) were delivered using MMV (91%) when compared to MPV (79%, P < 0.001) and BMV (59%, P < 0.001). The inspiratory time was longer during MMV (0.7 ± 0.2 s) and MPV (0.7 ± 0.2 s, P < 0.001 for both) compared to BMV (0.5 ± 0.2 s). Tidal volumes were significantly lower using BMV (0.4 ± 0.2 L) compared to MMV (0.6 ± 0.2 L, P < 0.001) and MPV (0.6 ± 0.3 L, P < 0.001), whereas no differences were observed when comparing MMV and MPV.

Conclusion

MMV reduces interruptions in chest compressions and produces a higher proportion of effective ventilations during lifeguard CPR. This suggests that CPR quality is improved using MMV compared to MPV and BMV.     

Comparison of automated and manual ventilation in a prehospital pediatric model

Objective. Portable transport ventilators (TV) and demand valves (DV) may be effective and easy-to-use alternatives to bag-valve (BV) for prehospital ventilation of adults. The purpose of the study was to determine whether such devices maintain arterial blood gases and airway pressures similar to those for BV in a pediatric swine model. Method. This study was a prospective, randomized, crossover design using immature swine (9.6 ± 0.9 kg) to model ventilation in small children. Anesthetized, intubated, paralyzed, and cannulated animals were ventilated initially on standard mechanical hospital ventilation (HV). They were then assigned in random order to 10-minute intervals of ventilation using BV, TV, low-frequency jet ventilation (JV), and DV. Data were analyzed using repeated-measures ANOVA and Tukey multiple comparisons (alpha = 0.05). Results. The PaO₂ exceeded 90 mm Hg for all animal/ventilation combinations. Blood PaCO₂ was lower for BV and DV than it was for TV, JV, or HV. In contrast, blood pH was higher for BV and DV than it was for TV, JV, or HV. Peak airway pressure was higher for BV than it was for HV, TV, or JV; it was lower for JV than it was for HV, TV, or BV. Conclusion. This animal model suggests that automated TV and JV may provide more effective ventilation of children than do manual BV or DV devices. Although promising, these findings require application in children under prehospital emergent conditions.     

Performance of noninvasive ventilation modes on ICU ventilators during pressure support: a bench model study

Objective Noninvasive ventilation (NIV) is often applied with ICU ventilators. However, leaks at the patient-ventilator interface interfere with several key ventilator functions. Many ICU ventilators feature an NIV-specific mode dedicated to preventing these problems. The present bench model study aimed to evaluate the performance of these modes. Design and setting Bench model study in an intensive care research laboratory of a university hospital. Methods Eight ICU ventilators, widely available in Europe and featuring an NIV mode, were connected by an NIV mask to a lung model featuring a plastic head to mimic NIV conditions, driven by an ICU ventilator imitating patient effort. Tests were conducted in the absence and presence of leaks, the latter condition with and without activation of the NIV mode. Trigger delay, trigger-associated inspiratory workload, and pressurization were tested in conditions of normal respiratory mechanics, and cycling was also assessed in obstructive and restrictive conditions. Results On most ventilators leaks led to an increase in trigger delay and workload, a decrease in pressurization, and delayed cycling. On most ventilators the NIV mode partly or totally corrected these problems, but with large variations between machines. Furthermore, on some ventilators the NIV mode worsened the leak-induced dysfunction. Conclusions The results of this bench-model NIV study confirm that leaks interfere with several key functions of ICU ventilators. Overall, NIV modes can correct part or all of this interference, but with wide variations between machines in terms of efficiency. Clinicians should be aware of these differences when applying NIV with an ICU ventilator. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Noninvasive pressure support versus proportional assist ventilation in acute respiratory failure

Background Although conventional pressure ventilation (PSV) decreases the rate of intubation in acute respiratory failure, patient-ventilator dyssynchrony is a frequent cause of failure. In proportional assist ventilation (PAV), pressure is applied by the ventilator in proportion to the patient-generated volume and flow; therefore, there is automatic synchrony between the patient's effort and the ventilatory cycle.Objective The aim of this study was to compare the effects of PSV and PAV during noninvasive ventilation in the treatment of acute respiratory failure.Design Prospective randomised study.Setting A multidisciplinary 24-bed intensive care unit of an acute-care teaching hospital in Alicante, Spain.Patients This study included 117 consecutive adult patients with acute respiratory failure randomised to noninvasive ventilation delivered by PSV (n = 59) or PAV (n = 58).Measurements and results There were no statistically significant differences between patients assigned to each mode of ventilation with regard to baseline parameters and aetiological diagnoses of acute respiratory failure. With regard to outcome data, no significant differences were observed between PSV and PAV in the frequency of intubation (37% vs 34%), mortality rate (29% vs 28%), and mean length of stay. Subjective comfort (0–10 visual analogue scale) was rated higher and intolerance occurred less frequently (3.4% vs 15%, P = 0.03) in the PAV than in the PSV mode.Conclusions Although PAV seems more comfortable and intolerance occurred less frequently, no major differences exist in terms of physiological improvement or in terms of outcomes when comparing PSV and PAV.An editorial regarding this article can be found in the same issue ()     

A comparison of continuous positive pressure ventilation,combined high frequency ventilation and airway pressure release ventilation on experimental lung injury

In pigs with oleic induced lung injury, the effectiveness of combined high frequency ventilation (CHFV, with VDR-Phasitron) and airway pressure release ventilation (APRV) were compared to continuous positive pressure ventilation (CPPV) in a randomized study. The respiratory rate was 15/min, CPAP 8 mmHg and FiO₂ 0.25. PaCO₂ was maintained at 5 kPa. PaO₂ was significantly lower with APRV (12.5±3.9 kPa, CPPV: 15.8±3.9 kPa, and CHFV: 15.5±3.2 kPa). This was in accordance with the lowest peak airway pressure during APRV (20.9±4.8 mmHg, CPPV: 26.3±4.4 mmHg and CHFV: 28.2±3.7 mmHg). There was no difference in the pericardiac pressure between the 3 ventilation modes. The pressure related depressive effects on the cardiovascular function during CHFV and APRV were similar to those during CPPV. Adequate oxygenation and ventilation could be achieved with both CHFV and APRV, but these methods were not superior to CPPV.The study was supported by Instrumentariumin Tiedesäätiö     

Haemodynamic performance and weaning from mechanical ventilation following open-heart surgery

Summary In 38 patients ventilated after open-heart surgery the effect of a 20 minutes spontaneous breathing period on right atrial pressure (RAP), left atrial pressure (LAP), pulmonary artery pressure (PAP), aortic pressure (AoP), ECG and cardiac index (CI) was monitored. Arterial bloodgas analysis before and during spontaneous breathing ruled out any respiratory failure. The test period of spontaneous breathing provoked an increase in systemic and pulmonary vascular resistance. By this and by a direct aggravation of cardiac failure the work of both ventricles dropped inspite of an increase in end-diastolic ventricular pressure. If these hemodynamic effects of a spontaneous breathing test period are taken as a guide for deciding, if a patient after open-heart surgery is ready for being extubated, the need for reintubation will be extremely rare. The study encourages us to use mechanical ventilation as an additional instrument for treating heart failure even if no respiratory failure is present.