窒息氧合技术对重度阻塞性睡眠呼吸暂停低通气综合征患者无通气安全时间的影响

目的 评价经鼻咽导管窒息氧合技术对重度阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者全麻诱导气管插管时无通气安全时间的影响。
方法 择期行全麻腭咽成形术的重度OSAHS患者80例,男62例,女18例,年龄18～56岁,BMI 30～42 kg/m²,ASA Ⅰ或Ⅱ级,改良Mallampati分级Ⅰ—Ⅲ级。采用随机数字法分为两组：经鼻咽导管窒息氧合组（N组）和对照组（C组）,每组40例。两组均采用相同的全凭静脉诱导方案,诱导后模拟长时间气管插管。N组意识消失后置入鼻咽导管,确认可以面罩通气,给予肌松药待肌松效果满意后置入喉镜暴露声门结构,并在此时开始经鼻咽导管给予15 L/min湿化纯氧。C组常规麻醉诱导,肌松效果满意后置入喉镜暴露声门结构。记录两组停止面罩通气时的呼气末氧浓度（CETO2）、面罩通气停止后SpO₂ 达到的最低值、插管后开始通气时的P_ET CO₂ 。记录患者无通气安全时间（停止面罩通气至患者SpO₂ 降至95%的时间）,插管后开始通气至SpO₂ 恢复至100%时间。记录术后24 h鼻腔出血、牙齿损伤、咽喉痛、声音嘶哑、口咽出血等气管插管相关并发症的发生情况。
结果 与C组比较,N组面罩通气停止后SpO₂ 达到的最低值明显升高（P＜0.05）,插管后开始通气时的P_ET CO₂ 明显升高（P＜0.05）,无通气安全时间明显延长（P＜0.05）,插管后开始通气至SpO₂ 回复至100%的时间明显缩短（P＜0.05）。两组面罩通气停止时的CETO2差异无统计学意义。两组鼻腔出血、牙齿损伤、咽喉痛、声音嘶哑、口咽出血等气管插管相关并发症差异无统计学意义。
结论 经鼻咽导管窒息氧合技术安全、简便,可以延长重度OSAHS患者全麻诱导气管插管时无通气安全时间,提高其全麻诱导的安全性。     

新型鼻咽通气道在老年患者无痛胃肠镜诊疗气道管理中的应用

目的 评价新型鼻咽通气道在老年患者无痛胃肠镜诊疗中气道管理的安全性和有效性。
方法 选择拟行无痛胃肠镜检查的老年患者96例,男52例,女44例,年龄≥65岁,BMI 18～35 kg/m²,ASA Ⅰ或Ⅱ级,Mallampati分级Ⅰ或Ⅱ级。采用随机数字表法将患者分成两组：鼻咽通气道组（N组）和面罩组（M组）,每组48例。麻醉诱导待患者睫毛反射消失后,N组经鼻腔插入新型鼻咽通气道,尾端连接供氧管路,M组行面罩通气。记录术中HR、MAP和SpO₂。记录麻醉药用量、诊疗操作时间、苏醒时间。记录HR<50次/分、MAP波动幅度超过基础值30%或MAP低于60 mmHg、低氧血症（SpO₂＜92%）、气道干预操作、鼻黏膜损伤等不良反应发生情况。记录患者及内镜医师满意情况。
结果N组在无痛胃肠镜诊疗过程中低氧血症发生率和需要气道干预操作的发生率明显低于M组（P<0.05）。N组内镜医师满意度明显高于M组（P<0.05）。N组有1例（2.1%）发生鼻黏膜损伤。两组HR<50次/分、MAP波动幅度超过基础值30%或MAP低于60 mmHg的发生率、麻醉药用量、诊疗操作时间、苏醒时间和患者满意度差异无统计学意义。
结论 新型鼻咽通气道可有效减少老年患者无痛胃肠镜低氧血症的发生,减少气道干预操作,提高内镜医师满意度,可安全有效应用于老年患者无痛胃肠镜诊疗。     

复合舒芬太尼时瑞马唑仑抑制老年患者鼻咽通气道置入反应的半数有效剂量

目的 探讨复合舒芬太尼时瑞马唑仑抑制老年患者鼻咽通气道置入反应的半数有效剂量（ED₅₀）。
方法 选择择期在鼻咽通气道下完成白内障手术的老年患者38例，年龄≥65岁，BMI 18～25 kg/m²，ASAⅠ—Ⅲ级。患者依次静脉注射舒芬太尼0.1 μg/kg，3 min后静脉注射瑞马唑仑，2 min后置入鼻咽通气道。首例患者给予瑞马唑仑0.2 mg/kg，采用改良Dixon序贯法确定下一例患者瑞马唑仑的剂量，若前一例患者鼻咽通气道置入时出现以下任意一种阳性反应（摇头、呛咳、体动、HR增快幅度>基础值的20%、SBP或DBP升高幅度>基础值的20%），则下一例麻醉诱导时瑞马唑仑剂量增加0.01 mg/kg，反之则减少0.01 mg/kg，直到出现7次折返后停止。采用Probit回归分析计算复合舒芬太尼时瑞马唑仑抑制老年患者鼻咽通气道置入反应的ED₅₀、95%有效剂量(ED₉₅)及95％可信区间（CI）。
结果 复合舒芬太尼时瑞马唑仑抑制鼻咽通气道置入反应的ED₅₀为0.193 mg/kg（95%CI 0.191～0.195 mg/kg），ED₉₅为0.209 mg/kg（95%CI 0.205～0.213 mg/kg）。
结论复合舒芬太尼时瑞马唑仑抑制老年患者鼻咽通气道置入反应的ED₅₀为0.193 mg/kg（95%CI 0.191～0.195 mg/kg）。     

经鼻湿化快速充气通气交换技术在住院医师规范化培训纤维支气管镜引导气管插管中的应用

目的 评价经鼻湿化快速充气通气交换技术（THRIVE）在住院医师规范化培训纤维支气管镜（纤支镜）引导气管插管中的应用效果。

方法 选择非麻醉专业学员10名，依据插管期间供氧方式的不同随机分为两组：THRIVE 组（T组）和对照组（C组），每组5名。每名学员需完成经纤支镜引导气管插管随机病例20例，共200例患者，男108例，女92例，年龄18～64岁，BMI 18～24 kg/m²，ASA Ⅰ或Ⅱ级。两组学员独立完成经纤支镜气管插管操作，插管期间T组使用 THRIVE 装置以FiO₂ 100%给氧，70 L/min，C组移开面罩进行插管。记录每例患者插管成功与否。绘制两组学员学习曲线，用累积和（CUSUM）方法建立学习曲线，运用累积和分析法算出掌握相应插管技术所需要的最小例数。记录学习曲线平台期前SpO₂<90%的例数，气道建立过程中是否有鼻出血、口咽腔处损伤、牙齿损伤、心律失常、喉痉挛等明显通气及插管相关不良反应。

结果 与C组比较，T组学员掌握纤支镜引导气管插管操作所需的最少插管例数明显减少（P<0.05），学习曲线平台期前SpO₂<90% 发生例数明显减少（P＜0.05）。两组在围插管期均未观察到明显通气及插管并发症。

结论 住院医师规范化培训行纤支镜引导气管插管的无呼吸氧合期应用THRIVE通气可明显改善学习曲线，降低围插管期患者低氧血症的发生率，且不增加通气相关并发症，适合临床推广应用。     

不同流速经鼻湿化快速充气通气联合无创通气对肥胖患者全麻诱导期胃进气的影响

目的 通过胃窦超声检查评估不同流速经鼻湿化快速充气通气（THRIVE）联合无创通气（NIV）在全麻诱导时对肥胖患者胃进气的影响。
方法 选择择期全麻手术患者72例,男29例,女43例,年龄18～64岁,BMI 30.0～39.9 kg/m²,ASA Ⅰ或Ⅱ级。随机分为三组：H30组、H50组、H70组,每组24例。三组均行THRIVE 30 L/min预给氧5 min后行全麻诱导。全麻诱导后三组分别接受相应氧流量大小（30、50、70 L/min,FiO₂ 100%）的THRIVE联合NIV（10 cmH₂O）行压力控制给氧。气管插管期,各组继续行对应流速THRIVE以提供窒息氧合。入室时以及诱导通气结束时,采用超声监测患者仰卧位胃窦部进气情况,超声图像出现“彗尾征”则定义为胃进气阳性（GI⁺）。记录全麻诱导期GI⁺的发生情况;记录入室时以及诱导通气结束时的胃窦部横截面积（CSA）;记录插管过程中SpO₂最低值以及诱导通气结束时PaO₂、PaCO₂、P_ETCO₂等呼吸参数;记录术后恶心呕吐、反流误吸、鼻咽部不适和气压伤等不良事件的发生情况。
结果 全麻诱导期H70组GI⁺发生率明显高于H30组、H50组（P<0.05）。与入室时比较,诱导通气结束时H70组胃窦部CSA明显增大（P<0.05）。诱导通气结束时H70组CSA明显大于与H30组、H50组（P<0.05）。插管过程中H50组、H70组SpO₂最低值明显高于H30组（P<0.05）;诱导通气结束时H50组、H70组PaO₂明显高于H30组,PaCO₂明显低于H30组（P<0.05）。三组恶心呕吐发生率差异无统计学意义。三组均无一例反流误吸、鼻咽部不适和气压伤。
结论 THRIVE 50 L/min联合NIV 10 cmH₂O压控给氧能为肥胖患者全麻诱导期提供较好的氧合,且明显降低胃进气发生率。     

肩高头后仰位对非插管全身麻醉纤维支气管镜检查术中气道梗阻和低氧的影响

目的：观察肩高头后仰位对非插管全身麻醉纤维支气管镜（FOB）检查术中气道梗阻和低氧的影响。
方法：选择拟行无痛FOB检查的患者170例,男97例,女73例,年龄18～64岁,BMI 18.5～28.0 kg/m²,ASA Ⅰ—Ⅲ级。采用随机数字法将患者分为两组：观察组（D组,n=84）和对照组（C组,n=83）。D组采用肩高头后仰位,C组采用平卧位。两组均采用丙泊酚复合舒芬太尼静脉全身麻醉,普通内镜面罩吸氧8～10 L/min,当改良警觉/镇静（MOAA/S）评分≤1分时开始实施FOB检查。记录术中低氧及采取矫正措施例数,麻醉诱导前（T1）、麻醉诱导后1 min（T2）、气管内表面麻醉（T3）、FOB检查时（T4）及检查结束时（T5）的HR、SBP、DBP、SpO₂。记录T2时腭后间隙和舌后间隙梗阻程度,术中声门显露情况和内镜医师操作舒适度。记录术后颈部不适、头痛、头晕和恶心呕吐等不良事件的发生情况。
结果：与C组比较,D组术中中度低氧、重度低氧、托下颌和辅助通气发生率明显降低（P<0.05）。与T1时比较,两组T3、T4时HR明显增快（P<0.05）,T2、T4、T5时SBP和DBP明显降低（P<0.05）,T2时SpO₂明显升高（P<0.05）,T4时SpO₂明显降低（P<0.05）;C组T3时SpO₂明显降低（P<0.05）。与C组比较,D组T4时SpO₂明显升高（P<0.05）,T2时舌后间隙无梗阻发生率明显升高,完全梗阻发生率明显降低（P<0.05）。与C组比较,D组声门显露差发生率明显降低,内镜医师操作舒适度明显升高（P<0.05）。两组术后不良事件发生率差异无统计学意义。
结论：肩高头后仰位可减轻非插管全身麻醉FOB检查术中的气道梗阻,降低术中低氧的发生率。     

驱动压导向呼气末正压通气对原位肝移植患者术中氧合和术后并发症的影响

目的： 评价驱动压导向呼气末正压（PEEP）通气对原位肝移植术（OLT）患者术中氧合和术后并发症的影响。
方法： 选择2020年1月至2023年9月行OLT患者118例,男89例,女29例,年龄18～70岁,BMI＜28 kg/m² ,ASA Ⅲ或Ⅳ级。采用随机数字表法将患者分为两组：驱动压组（D组）和固定PEEP组（P组）,每组59例。两组全麻期间均采用容量控制通气,I∶E 1∶2,V_T 6 ml/kg（理想体重）,RR 10～15次/分。D组在机械通气5 min后开始PEEP滴定试验,将PEEP从2 cmH₂O逐渐递增到10 cmH₂O,选择能产生最低驱动压的PEEP,维持该PEEP直至手术结束。P组术中维持PEEP 5 cmH₂O。记录术中出入量、血管活性药物使用情况。记录插管后5 min（T₁）、无肝期（T₂）、新肝期（T₃）、手术结束即刻（T₄）的HR、SBP、DBP、气道峰压（Ppeak）、气道平台压（Pplat）、PEEP、血气分析结果,并计算驱动压、动态肺顺应性（Cdyn）、氧合指数（OI）、死腔率（V_D/ V_T）。记录术后7 d内术后肺部并发症（PPCs）的发生情况。
结果： 与P组比较,D组晶体液输注量明显增加,去甲肾上腺素、去氧肾上腺素及肾上腺素使用率明显升高（P<0.05）。与T₂时比较,两组T₁、T₃、T₄时HR明显减慢,SBP、DBP明显升高（P<0.05）。与T₁时比较,两组T₂—T₄时Ppeak、Pplat、驱动压、OI明显升高,T₃、T₄时Cdyn明显降低（P<0.05）。与P组比较,D组术后7 d内PPCs发生率明显降低（P<0.05）。两组其余指标差异无统计学意义。
结论： 驱动压导向PEEP通气可改善原位肝移植患者术中氧合,降低PPCs发生率,但术中血管活性药物的使用率升高。     

不同通气模式对腹腔镜肝切除术患者出血量和术后肝功能的影响

目的 探讨不同通气模式对腹腔镜肝切除术患者出血量和术后肝功能的影响。
方法 选择择期全麻下行腹腔镜肝切除术患者60例，男35例，女25例，年龄18～64岁，BMI 18.5～24.0 kg/m²，ASA Ⅱ或Ⅲ级。采用随机数字表法将患者分为两组：压力控制通气（PCV）组和容量控制通气（VCV）组，每组30例。PCV组通过调整气道峰压，使术中VT达到理想体重×8 ml，同时调整RR维持P_ETCO₂ 35～45 mmHg；V组VT设定为理想体重×8 ml，同时调整RR维持P_ETCO₂ 35～45 mmHg。记录麻醉诱导后10 min（T₀）、气腹后10 min（T₁）、切肝前10 min（T₂）、切肝后10 min（T₃）、气腹结束后10 min（T₄）吸气峰压（Ppeak）、气道平均压（Pmean）、CVP、PaCO₂和氧合指数（PaO₂/FiO₂）。记录术中胶体液用量和出血量，术后24、48和72 h丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）以及腹腔引流量。
结果 与T₀时比较，T₁—T₃时两组Ppeak均明显升高（P＜0.05）；T₁—T₄时VCV组、T₃和T₄时PCV组CVP均明显升高（P＜0.05）。与VCV组比较，PCV组T₁、T₂时CVP明显降低（P＜0.05），术中胶体液用量和出血量明显减少（P＜0.05）。两组术后24、48和72 h的ALT、AST和腹腔引流量差异无统计学意义。
结论 压力控制通气模式下腹腔镜肝切除术中患者出血量明显减少，可能与术中较低的气道峰压有关，但两种不同通气模式下患者术后肝功能损伤无明显差异。     

氟比洛芬酯对胸腔镜右肺叶切除术患者单肺通气期间肺功能的影响

目的： 观察氟比洛芬酯对胸腔镜右肺叶切除术患者采用封堵器行单肺通气期间肺氧合功能、呼吸力学及肺部并发症的影响。
方法： 选择择期全麻下行胸腔镜右肺叶切除术采用封堵器行单肺通气的患者60例,男25例,女35例,年龄35～64岁,BMI 18～28 kg/m²,ASA Ⅰ或Ⅱ级。采用随机数字表法将患者分为两组：氟比洛芬酯组（F组）和对照组（C组）,每组30例。F组在麻醉诱导前15 min静注氟比洛芬酯1.0 mg/kg,C组不予处理。于麻醉诱导前20 min（T₀）、单肺通气30 min（T₁）、单肺通气60 min（T₂）、双肺通气15 min（T₃）时抽取桡动脉血行血气分析,计算氧合指数（OI）并记录SpO₂。记录T₁、T₂时的气道峰压（Ppeak）、气道平台压（Pplat）、肺动态顺应性（Cdyn）和无效腔气量与潮气量之比（V_D/V_T）。记录单肺通气期间低氧血症发生情况、补救例数、术后转ICU例数、术后72 h内肺不张、急性肺损伤和肺炎发生情况。
结果： 与C组比较,F组T₁时SpO₂、T₁—T₃时PaO₂和OI、T₁、T₂时Cdyn明显升高（P<0.05）;T₁、T₂时Ppeak和V_D/V_T、T₂时Pplat明显降低（P<0.05）。两组无一例单肺通气期间发生低氧血症和补救、术后转入ICU、术后72 h内发生肺不张、急性肺损伤和肺炎。
结论： 对胸腔镜右肺叶切除术采用封堵器行单肺通气的患者,麻醉诱导前静注氟比洛芬酯有助于改善单肺通气期间肺氧合功能,优化呼吸力学参数。     

鼻咽通气道在老年腹部手术患者麻醉恢复期的应用

目的 观察鼻咽通气道用于老年腹部手术患者,在麻醉恢复期维持上呼吸道通畅的有效性及可行性.方法 择期全麻患者120例,年龄65～75岁,ASA Ⅰ或Ⅱ级,随机分为鼻咽通气道(A组),口咽通气道(B组),手法托颌组(C组),每组40例.术毕拔除气管导管后,随即A组置入鼻咽通气道,B组置人口咽通气道,C组手法托颌,三组均用面罩吸氧(氧流量2 L/min).记录A、B组置入口/鼻通气道时间及一次置管成功率,观察三组拔除气管导管前(To)、拔管后/置入通气管(C组手法托颌)后5 min(T1)、10 min(T2)、20 min(T3)的SpO2、PaCO2、HR、SBP、DBP,T3后即对三组进行舒适度VAS评分.结果 T2、T3时B、C组PaCO2、SBP明显高于、HR明显快于A组(P＜0.05),VAS评分A组明显高于B、C组(P＜0.05).结论 鼻咽通气道维持麻醉恢复期老年腹部手术患者的上呼吸道通畅效果较为理想,且患者耐受性佳.     

Continuous-flow apneic ventilation with small endobronchial catheters

This study compares gas exchange and hemodynamic parameters during bronchial insufflation with two different internal diameter (ID) catheters (2.5 and 1.4 mm) at a constant mean gas exit velocity. Anesthetized, paralyzed dogs were instrumented to monitor arterial, central venous, and airway pressures, blood gases, temperature, ECG, and ventilated using continuous flow apneic ventilation (CFAV) via 2.5-mm or 1.4-mm ID bronchial insufflation catheters positioned 1.25 bronchial diameter units (BDU) beyond the carina. Initially, flow was adjusted to provide adequate oxygenation and ventilation through the 2.5-mm ID catheters. After a 30-min stabilization, physiological parameters were recorded and the mean gas exit velocity was calculated. The 2.5-mm ID insufflation catheters were then replaced by 1.4-mm ID catheters and the bronchial insufflation flow adjusted so as to produce the same mean gas exit velocity as for the 2.5-mm ID catheters. After a 30-min stabilization period, physiological parameters were again recorded. No significant differences were noted in arterial, central venous, or airway pressures, temperature, heart rate, pH, PaCO2, and PaO2 between the 2.5-mm and 1.4-mm ID bronchial insufflation catheters. However, significantly less bronchial insufflation flow (69.7%) was required to maintain oxygenation and ventilation for the 1.4-mm ID bronchial insufflation catheters.     

高频通气治疗吸入性损伤

High frequency ventilation (HFV) is a kind of lung protective ventilation strategy. High-frequency jet ventilation (HFJV) can decrease the water content, relocate interstitial fluid and accelerate lymph flow in the lung of dogs with smoke inhalation injury. HFJV can effectively improve breathing mechanics and gas exchange in dogs with smoke inhalation injury. Clinical application also proves that HFV is efficient in treatment of inhalation injury.     

Pressure-controlled ventilation is superior to volume-controlled ventilation with a laryngeal mask airway in children

Background:  This prospective, randomized, crossover study had two purposes: first, to determine whether pressure-controlled ventilation (PCV) is safer than volume-controlled ventilation (VCV) by preventing gastric insufflation in children ventilated through an laryngeal mask airway (LMA); second, to assess whether the measurement of LMA leak pressure (P_leak) is useful for preventing leakage during positive pressure ventilation (PPV).
Methods:  Forty-one, 2 to 15-year-old children underwent general anesthesia with an LMA. The expiratory valve was set at 30 cmH₂O and P_leak was measured using constant gas flow. Children were randomly ventilated using PCV or VCV for 5 min in order to reach a P_ETCO₂ not exceeding 45 mm Hg, and then they were ventilated with the alternative mode. If the target P_ETCO₂ could not be obtained in one mode, we switched to the other. If both modes failed, children were intubated. Tidal volumes, P_ETCO₂ and airway pressures were noted and compared between modes. Gastric insufflation was checked by epigastric auscultation.
Results:  PCV provided more efficient ventilation than VCV, as targeted P_ETCO₂ was obtained without gastric insufflation using PCV in all cases except one, whereas VCV failed in three cases. No gastric insufflation occurred when ventilating below peak.
Conclusions:  These findings suggest that in the age group studied, PCV is more efficient than VCV for controlled ventilation with a laryngeal mask. Gastric insufflation did not occur with this mode.     

Coping with COVID-19: ventilator splitting with differential driving pressures using standard hospital equipment

The global COVID-19 pandemic has led to a worldwide shortage of ventilators. This shortage has initiated discussions on how to support multiple patients with a single ventilator (ventilator splitting). Ventilator splitting is incompletely tested, experimental and the effects have not been fully characterised. This study investigated the effect of ventilator splitting on system variables (inspiratory pressure, flow and volume) and the possibility of different ventilation targets for each limb using only standard hospital equipment. Experiments were conducted on two test lungs with different compliances (0.02 l.cmH₂O⁻¹ and 0.04 l.cmH₂O⁻¹). The ventilator was used in both pressure and volume control modes and was set to ventilate the low compliance lungs at end-tidal volumes of 500 ± 20 ml. A flow restrictor apparatus consisting of a Hoffman clamp and tracheal tube was connected in series to the inspiratory limb of the high compliance test lungs and the resistance modified to achieve end-tidal volumes of 500 ± 20 ml. The restriction apparatus successfully modified the inspiratory pressure, minute ventilation and volume delivered to the high compliance test lungs in both pressure control (27.3–17.8 cmH₂O, 15.2–8.0 l.min⁻¹ and 980–499 ml, respectively) and volume control (21.0–16.7 cmH₂O, 10.7–7.9 l.min⁻¹ and 659–498 ml, respectively) ventilation modes. Ventilator splitting is not condoned by the authors. However, these experiments demonstrate the capacity to simultaneously ventilate two test lungs of different compliances, and using only standard hospital equipment, modify the delivered pressure, flow and volume in each test lung.     

术侧肺部分通气法与单肺通气的比较研究

目的 与单肺通气(one-lung ventilation,OLV)比较术侧肺部分通气(partial ventilation of independent lung,PLV)情况下的氧合与气道压力.方法 16例接受食道手术的患者随机分为两组,进行自身对照交叉研究.在双肺通气后按不同顺序接受OLV和术侧肺PLV,比较3种通气时氧合指数(oxygen index,OI)及气道压力的变化.结果 两种通气方式下OI均显著低于双肺通气(two-lung ventilation,TLV),但PLV时显著高于OLV(PLV391±112,OLV134±53,TLV530±92,P<0.05);气道压力值在PLV时也显著低于OLV[Ppeak:(19±3)cm H2O vs(27±5)cm H2O,Pplat:(17±2)cm H2O vs(23±3)cm H2O,P<0.05](1 cm H2O=0.098 kPa). 结论PLV显著改善了氧合和呼吸力学指标.     

Effectiveness of pressure support ventilation for mechanical ventilatory support in patients with status asthmaticus

We compared the effects of pressure support ventilation (PSV) with those of assist control ventilation (ACV) on breathing patterns and blood gas exchange in six patients with status asthmaticus. Both PSV and ACV delivered adequate minute ventilation (PSV: 7.5 +/- 1.4 l/min/m2, ACV: 7.3 +/- 1.3 l/min/m2) to correct respiratory acidosis (pH = 7.33 +/- 0.12 during both PSV and ACV) and prevent hypoxia. Peak airway pressure during PSV was significantly lower with the same tidal volume than that during ACV (PSV: 30 +/- 10 cmH2O (2.9 +/- 1.0 kPa), ACV: 50 +/- 13 cmH2O (4.9 +/- 1.3 kPa)). The lower airway pressure during PSV was due to persistent inspiratory muscle activity. The oxygen cost of breathing estimated by oxygen consumption was equivalent in both modes. We conclude that PSV is effective in supplying tidal volumes adequate to improve hypercarbia at markedly lower airway pressures than ACV.     

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目的　探讨适应性支持通气(ASV)对术后恢复期急性肺损伤(ALI)呼吸力学的影响。方法　采用自身对照方法,对广东省人民医院2 0 0 3年1～9月2 3例术后ALI病人序贯应用同步间歇指令 压力支持通气模式(SIMV PS)和ASV模式进行机械通气(MV) ,记录两种模式下的各项呼吸力学参数。结果　全部病人均成功脱机,总呼吸频率明显降低(P <0 . 0 5 ) ,自主呼吸频率增加(P >0 . 0 5 ) ,潮气量(VT)明显升高(P <0 . 0 5 ) ,平台压(Pplat)和平均气道压(Pawm)有所升高(P <0 .0 5 ) ,顺应性(Cst)有所下降,P0. 1(0. 1s的口腔闭合压)稍有下降(P >0 .0 5 ) ,生命体征、血气分析和血流动力学指标无明显变化。结论　ASV对术后ALI病人,可根据病人的呼吸力学状况自动调整吸气压力支持水平,提高潮气量、降低呼吸频率,而对血流动力学和生命体征没有影响。     

小儿喉罩通气时压力控制通气和容量控制通气的比较

目的　比较小儿喉罩通气时压力控制通气(PCV)和容量控制通气(VCV)对气道压力 和喉罩漏气的影响。方法　34例全麻下择期手术的小儿,年龄3～12岁,ASAⅠ～Ⅱ级。静脉麻醉 诱导后置入喉罩。患儿按随机顺序接受VCV和PCV两种通气方式,通气期间保持相同的呼气末二 氧化碳分压(PETCO2)。结果　PCV时气道峰压和漏气率明显低于VCV(P<0.01)。PCV时2例患 儿气道峰压>20cmH2O,而VCV时有9例患儿气道峰压>20cmH2O(P<0.05)。PETCO2和循环 参数无显著性差异。结论　小儿全麻喉罩通气期间,PCV能在较低的气道压力下提供有效的肺通气 效果。     

The association of postoperative pulmonary complications in 109,360 patients with pressure‐controlled or volume‐controlled ventilation

We thought that the rate of postoperative pulmonary complications might be higher after pressure‐controlled ventilation than after volume‐controlled ventilation. We analysed peri‐operative data recorded for 109,360 adults, whose lungs were mechanically ventilated during surgery at three hospitals in Massachusetts, USA. We used multivariable regression and propensity score matching. Postoperative pulmonary complications were more common after pressure‐controlled ventilation, odds ratio (95%CI) 1.29 (1.21–1.37), p < 0.001. Tidal volumes and driving pressures were more varied with pressure‐controlled ventilation compared with volume‐controlled ventilation: mean (SD) variance from the median 1.61 (1.36) ml.kg^?1 vs. 1.23 (1.11) ml.kg^?1, p < 0.001; and 3.91 (3.47) cmH₂O vs. 3.40 (2.69) cmH₂O, p < 0.001. The odds ratio (95%CI) of pulmonary complications after pressure‐controlled ventilation compared with volume‐controlled ventilation at positive end‐expiratory pressures < 5 cmH₂O was 1.40 (1.26–1.55) and 1.20 (1.11–1.31) when ≥ 5 cmH₂O, both p < 0.001, a relative risk ratio of 1.17 (1.03–1.33), p = 0.023. The odds ratio (95%CI) of pulmonary complications after pressure‐controlled ventilation compared with volume‐controlled ventilation at driving pressures of < 19 cmH₂O was 1.37 (1.27–1.48), p < 0.001, and 1.16 (1.04–1.30) when ≥ 19 cmH₂O, p = 0.011, a relative risk ratio of 1.18 (1.07–1.30), p = 0.016. Our data support volume‐controlled ventilation during surgery, particularly for patients more likely to suffer postoperative pulmonary complications.     

High-frequency oscillatory ventilation combined with intermittent mandatory ventilation in critically ill neonates and infants

We have evaluated the high-frequency oscillatory ventilation (HFOV) combined with intermittent mandatory ventilation (IMV) in critically ill neonates and infants using the Babylog 8000 SW 4.0.
We used HFOV combined with IMV as a rescue mode in 10 neonates and infants aged 1 day to 17 months, who were receiving maximal conventional ventilation for severe respiratory failure.
There was a significant reduction in inspired oxygen requirement when starting HFOV combined with intermittent mandatory ventilation (IMV), from a baseline mean of 0.90 (CI₉₅ 0.79-1.01) to 0.55 (CI₉₅ 0.40-0.71) at 6h and 0.44 (CI₉₅ 0.37-0.52) at 12h. There was also an overall improvement in gas exchange with complete haemodynamic stability.
These data suggest that HFOV-IMV mode offers significant improvement as a rescue mode for neonates and infants with severe respiratory failure.