压力控制通气在急性呼吸窘迫综合征患者的应用

目的观察急性呼吸窘迫综合征（ARDS）患者应用压力控制通气（PCV）治疗时的气道压力、氧合、血液动力学变化,探讨其治疗效果和肺保护作用。方法18例ARDS患者在使用小潮气量（6～8ml／kg）、〈25次／分的频率容量控制通气（VCV）,气道峰压接近35～40cmH2O,而氧合改善仍不满意时,改为PCV方式机械通气,观察此时气道压力、氧合、血液动力学指标的变化。结果在呼出潮气量相近的情况下,PCV时的气道峰压较VCV时明显降低,平均气道压、中心静脉压升高,但无显著性差异;平均动脉压无明显变化;PCV治疗后24hPaO2、氧合指数明显升高,心率显著减慢,吸气压力增大时潮气量随之增加,未发生气压伤。结论PCV治疗ARDS在改善氧合、减少气压伤、实施肺保护方面较VCV更为有效。     

压力和容量控制通气对患儿呼吸力学的影响

目的采用自身对照的方法比较压力控制通气(PCV)和容量控制通气(VCV)对患儿术中呼吸力学及血流动力学的影响。方法全麻下择期手术患儿30例,年龄0~6个月,术前给予患儿右美托咪定负荷剂量0.1μg·kg-1·min-1,10 min内输注完毕。待患儿安静入睡,记录此时RR及呼气末二氧化碳(EtCO2)作为模拟生理睡眠状态下的RR及EtCO2。常规麻醉诱导后,顺序给予容量控制通气(VCV)及压力控制通气(PCV),以患儿模拟生理状态下的RR为基础,调节通气压力或VT,以维持术前基础EtCO2。连续监测患儿ECG、NIBP、SpO2、RR、EtCO2、BIS及气道峰压(Ppeak)、气道平均压(Pmean)、气道平台压(Pplat)、Vt、分钟通气量(MV)、肺顺应性(Compl)等呼吸力学参数。结果 PCV 15min时患儿Ppeak值(16.8±2.9)cm H2O明显低于VCV 15min时患儿的(18.3±3.3)cm H2O,而PCV 15 min时患儿Pmean值(7.0±1.8)cm H2O明显高于VCV 15min时患儿的(6.2±1.7)cm H2O(P0.05);患儿采用两种通气模式时Pplat、Vt、MV、Compl、BIS及血流动力学指标差异无统计学意义。结论两种通气模式都可安全有效地应用于新生儿和小婴儿术中机械通气,而PCV模式在预防患儿Ppeak过高、改善氧合方面更有优势。     

不同充气量的食管引流型喉罩对于全麻患者机械通气的影响

目的研究不同充气量的食管引流型喉罩(PLMA)用于全麻患者机械通气时的囊内压及对患者通气功能的影响。方法40例ASAⅠ或Ⅱ级妇科及乳腺手术患者全麻下置入4号PLMA,在最大充气量30ml(MAX)、25ml(5/6MAX)、20ml(2/3MAX)、15ml(1/2MAX)、10ml(1/3MAX)、5ml(1/6MAX)和0充气量时监测囊内压并用旁气流通气监测法(SSS)监测患者的通气功能的变化,同时记录气道漏气情况。结果所有患者MAX的套囊内压都大于60cmH2O;气道密闭压(Pleak)随通气罩充气量减小而逐渐降低,而气道阻力(Raw)逐渐增大。在1/3MAX充气量以下的气道漏气发生率、动态胸肺顺应性(Compl)、1/6MAX以下的呼出潮气量(TVex)和呼出分钟通气量(MVex)与MAX时相比差异有统计学意义(P<0.05或P<0.01)。结论最适宜的充气方法为开始充气1/2MAX,如果气道压<15cmHO,喉罩周围有漏气,再增加5～10ml充气量。     

I-gel喉罩与普通喉罩在全麻乳腺手术中的应用比较

目的比较I-gel喉罩与普通喉罩用于全麻乳腺手术中的气道管理效果。方法全麻下行乳腺肿物切除术患者60例,ASAⅠ或Ⅱ级,随机均分为I-gel喉罩组(I组)和普通喉罩组(S组)。记录首次插入成功率、插入时间、气道密封压、纤维支气管镜检查分级情况、苏醒时间、拔出喉罩时间及喉罩插入成功后15、30、45、60min时HR、BP、SpO2、PETCO2及气道峰压(Ppeak)值;记录并发症的发生情况。结果 I组首次插入成功率为90%,高于S组的76%(P<0.05);插入时间为(15.2±5.6)s,短于S组的(26.5±8.3)s(P<0.05);气道密封压为(27.6±4.7)cmH2O,高于S组的(23.8±4.5)cmH2O(P<0.05);纤维支气管镜评级优于S组(P<0.05)。两组患者苏醒时间、拔除喉罩时间和各时点HR、BP、SpO2、PETCO2及Ppeak差异无统计学意义;两组患者拔除喉罩后并发症的发生率差异无统计学意义。结论 I-gel喉罩用于全麻乳腺手术气道管理的效果优于普通喉罩。     

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。     

不同通气模式对单肺通气影响的Meta分析

目的 采用Meta分析的方法评价压力控制通气(pressure controlled ventilation,PCV)与容量控制通气(volume controlled ventilation,VCV)对术中单肺通气(one lung ventilation,OLV)患者呼吸力学及循环的影响. 方法 检索PubMed、Embase、Cochrane图书馆,检索时间从建库至2016年2月.收集术中OLV使用PCV与VCV的临床随机对照试验(randomizedcontrolled trim,RCT).采用Cochrane协作网系统评价法评价纳入文献的质量,采用RevMan 5.0软件对收集的患者资料进行Meta分析评价. 结果 共纳入14项研究,包括964例患者,其中PCV组480例,VCV组484例.与VCV组比较:在开胸前双肺通气时(T1),PCV组气道平均压(mean airway pressure,Pmean)比值比(odds ratio,OR)[0R=-0.22,95％CI(-0.42,-0.01),P＜0.05]较低;OLV时(T2),PCV组气道峰压(peak airway pressure,Ppeak)[加权均数差(weighted mean difference,WMD)=-1.37,95％CI(-1.69,-1.05)]及气道平台压(pause pressure,Plateau)较低[WMD=-0.29,95％CI(-0.51,-0.07)],而PaO2高[WMD=0.52,95％CI(0.08,0.95)];关胸后双肺通气时(T3),PCV组Ppeak较低[WMD=-0.63,95％CI(-1.09,0.17)]. 结论 与VCV比较,OLV期间PCV可提供较低的气道压,可能是一种较好的通气模式.     

压力控制通气与容量控制通气对腹腔镜胆囊切除术患者呼吸功能的影响

目的探讨压力通气模式(PCV)与容量通气模式(VCV)对腹腔镜胆囊切除术患者呼吸功能的影响,以期为腹腔镜胆囊切除术通气模式的选择提供参考。方法择期行腹腔镜胆囊切除术的患者共计120例,年龄31~56岁,ASA分级Ⅰ~Ⅱ级,体重指数(BMI)18.1~28.4kg/m2,随机分为PCV组和VCV组,每组60例,分别记录气管插管后5分钟(T_1)、气腹后10分钟(T_2)、气腹后30分钟(T_3)、撤除气腹后10分钟(T_4)患者气道峰压、气道平台压、平均气道压、肺顺应性,并随访患者术后14天皮下气肿、气胸、肺部感染等并发症发生情况。结果两组患者T_1时点气道峰压、气道平台压、平均气道压、肺顺应性均未见明显统计学差异。PCV组患者T_2、T_3时点气道峰压、气道平台压、平均气道压明显低于VCV组(P0.05)。在并发症方面,仅有VCV组1位患者发生术后肺部感染。结论对腹腔镜胆囊切除术患者而言,PCV模式能够保持较高的肺顺应性及较低的气道峰压和气道平台压,有利于降低术中肺部气压伤的发生风险,与VCV相比具有明显优势。     

食管引流型与标准型喉罩通气道在全身麻醉患者的应用

目的比较食管引流型喉罩通气道(PLMA)和标准型喉罩通气道(SLMA)在全身麻醉患者的应用。方法ASAⅠ~Ⅱ级择期整形外科手术患者60例,随机均分为PLMA组和SLMA组,常规麻醉诱导后,分别插入PLMA或SLMA,并将通气罩充气至60cmH2O。评价两种喉罩通气道的插入特征、气道密封压和漏气部位,记录麻醉诱导前后、喉罩插入时和喉罩插入后5min内SBP、DBP和HR的变化情况。记录麻醉期间发生的呼吸并发症和呼吸道损伤情况。结果PLMA组首次插入即获得满意肺通气的例数高于SLMA组,但PLMA组操作时间明显长于SLMA组(P<0·05)。PLMA组通气罩充气量和气道密封压明显高于SLMA组(P<0·05)。两组插入操作所致的血液动力学反应相似,而且均非常轻微。结论与SLMA相比,PLMA可达到更好的气道密封性,并可提供良好的胃管插入通路,是全身麻醉患者安全有效的呼吸道管理工具之一。     

喉罩静吸复合麻醉期间患者通气功能的监测

应用ＤａｔｅｘＵｌｔｉｍａ监护仪，监测喉罩全麻时的呼吸功能变化。结果显示：麻醉诱导后，呼吸抑制，ＳｐＯ２显著降低，ＰＥＴＣＯ２逐渐增加。插喉罩后，呼吸道通畅。机械通气时，气道峰压低于漏气压，通气效果良好，患者血气值在正常范围。我们认为：在良好的监测下，可以扩大喉罩全麻的应用范围。     

妇科手术患者Guardian喉罩与Supreme喉罩气道管理效果的比较

目的 比较Guardian喉罩与Supreme喉罩用于妇科手术患者气道管理的效果.方法 择期全麻下行妇科手术患者120例,年龄19～80岁,体重50～70kg,ASA分级Ⅰ或Ⅱ级,随机分为2组:Supreme喉罩组(S组,n=59)和Guardian喉罩组(G组,n=61).麻醉诱导后置入4号喉罩,行机械通气.术中监测BP、HR、SpO2、PETCO2和Ppeak.记录喉罩置人情况、置入时间、纤维支气管镜检查分级、气道密封压、正常通气时(VT 8 ml/kg)的气道压、大潮气量(VT20 ml/kg)通气试验时的气道压和漏气的发生情况、术中口咽部漏气的发生情况、拔除喉罩时不良反应和术后咽喉部不良反应的发生情况、麻醉时间、手术时间、喉罩拔除时间和苏醒时间.结果 两组喉罩置入成功率、置入时间、正常通气时的气道压、大潮气量通气试验时的气道压、拔除喉罩时罩体带血和术后咽喉疼痛、声音嘶哑和吞咽困难的发生率、麻醉时间、手术时间、喉罩拔除时间和苏醒时间差异无统计学意义(P＜0.05).两组患者BP、HR、SpO2、Ppeak和PETCO2均在正常范围内.与S组比较,G组纤维支气管镜检查分级和气道密封压升高,大潮气量通气试验时漏气和术中口咽部漏气的发生率降低(P＜0.01).结论 Guardian喉罩和Supreme喉罩置入简单易行,气道密封效果好,可有效保证通气,对咽喉部的刺激小.Guardian喉罩用于妇科手术患者气道管理的效果更好.     

Non-invasive ventilation in surgical patients in a district general hospital

We have retrospectively audited the use of non-invasive ventilation (NIV) in surgical patients. We analysed the case notes of 38 surgical patients who received NIV over a 9-month period. Twenty-three patients received NIV following emergency surgery, eight after elective surgery, and seven did not have an operation. Co-morbidity was common. The commonest reasons for starting NIV were chest infection, acute respiratory distress syndrome and pulmonary oedema. NIV was often only one aspect of treatment in surgical patients with complex medical problems. With intensive support from the critical care outreach team, NIV can be safely delivered on a surgical ward, and may sometimes prevent intensive care unit admission. Use of NIV on the intensive care unit may obviate the need for tracheal intubation in some patients. In very ill surgical patients with a poor prognosis, NIV was frequently used as the ceiling of respiratory support.     

Principles of artificial ventilation

The application of intermittent positive pressure ventilation (IPPV) during the 1952 Copenhagen polio epidemic led to the development of the world's first intensive care unit. The requirement for ventilatory support is the most common indication for intensive therapy unit (ITU) admission and is a defining feature of the specialty. Ventilator technology continues to develop and there are many ways to deliver IPPV. The variety of modes of ventilation is increasingly complex and expanding, without evidence that any one mode is associated with improved outcome. Ventilatory support is part of the treatment for a range of conditions including acute respiratory failure, raised intracranial pressure (ICP) and circulatory shock. Ventilator-associated lung injury is reduced by using low tidal volumes and limiting plateau airway pressure to less than 30 cmH₂O. Prolonged artificial ventilation has an associated morbidity and mortality and thus should be reviewed by an expert clinician on a daily basis. Weaning aims to identify those patients who will be able to breathe spontaneously. Protocols exist to facilitate timely extubation without the need for re-intubation.     

单肺通气时机械通气模式的研究进展

背景 单肺通气(one lung ventilation,OLV)实施过程中最常见的并发症是低氧血症,也是麻醉医师遇到的最严重的挑战. 目的 近来研究表明OLV本身能够引起低氧血症和急性肺损伤(acute lung injury,ALI).因此,如何实施OLV时机械通气模式,降低肺内分流率(pulmonary shunt fraction,Qs/Qt)、预防低氧血症一直是临床研究的热点. 内容 综述提高吸入氧分数(fraction of inspiration O2,FiO2)、控制通气模式、高频通气(high frequency ventilation,HFV)、潮气量(tidal volume,Vt)、反比通气、部分液体通气(partial liquid ventilation,PLV)、持续气道正压通气(continuous positive airway pressure,CPAP)、呼气末正压通气(positive end-expiratory pressure,PEEP)等通气模式,以及实施联合多种模式的保护性肺通气策略. 趋向 综合运用多种预防OLV期间低氧血症的通气模式取得良好的效果,但应针对患者和手术情况制定OLV时机械通气模式.     

Principles of artificial ventilation

The application of intermittent positive pressure ventilation (IPPV) during the 1952 Copenhagen polio epidemic led to the development of the world’s first intensive care unit. The requirement for ventilatory support is the most common indication for intensive therapy unit (ITU) admission and is a defining feature of the specialty. Ventilator technology continues to develop and there are many ways to deliver IPPV. The variety of modes of ventilation is increasingly complex and expanding, without evidence that any one mode is associated with improved outcome. Ventilatory support is part of the treatment for a range of conditions including acute respiratory failure, raised intracranial pressure (ICP) and circulatory shock. Ventilator-associated lung injury is reduced by using low tidal volumes and limiting plateau airway pressure to less than 30 cmH₂O. Prolonged artificial ventilation has an associated morbidity and mortality and thus should be reviewed by an expert clinician on a daily basis. Weaning aims to identify those patients who will be able to breathe spontaneously. Protocols exist to facilitate timely extubation without the need for re-intubation.     

A clinical trial of volume- versus pressure-controlled intraoperative ventilation during laparoscopic bariatric surgeries

BackgroundIntra-operative ventilation is often challenging in patients with morbid obesity undergoing bariatric surgery.ObjectivesTo test the noninferiority of pressure-controlled ventilation (PCV) to volume-controlled ventilation (VCV) in respiratory mechanics.SettingBariatric Surgery Center, Iran.MethodsIn a randomized open-labeled clinical trial, 66 individuals with morbid obesity undergoing laparoscopic bariatric surgeries underwent intraoperative ventilation with either PCV or VCV. The measurements taken were peak and mean airway pressures (H₂O), partial pressure of arterial oxygen (PaO₂), partial pressure of arterial carbon dioxide (PaCO₂) and end-tidal carbon dioxide (CO₂). We additionally collected pulse-oximetric oxygen saturation, inspiratory concentration of oxygen (FiO₂), and hemodynamic variables. Data were analyzed with repeated measures over the time of intubation, after peritoneal insufflation, and every 15 minutes, thereafter up to one hour.ResultsPCV mode was successful to sustain adequate ventilation in 97% of the patients, which was similar to the 94% success rate of the VCV mode. Peak airway pressure increased 6 cmH₂O and end-tidal CO₂ rose by 5 mm Hg after abdominal insufflation in both groups (P = .850 and .376). Alveolar-arterial oxygen gradient similarly increased within 30 minutes after tracheal intubation both in PCV and VCV groups, with small trend of being higher in the VCV group. The ratio of dead space to tidal volumes (VD/VT) did not have a meaningful change (P = .724).ConclusionPCV was noninferior to VCV during laparoscopic bariatric surgery. Either mode of ventilation could be alternatively used during the anesthesia care of these patients.     

Respiration: ventilation

Anaesthetists and intensivists directly manipulate pulmonary function, in particular ventilation. A sound and thorough working knowledge of applied pulmonary physiology of ventilation is essential to the safe conduct of anaesthesia and intensive care medicine. This article discusses pulmonary anatomy, gas exchange in the lung, the mechanics of ventilation, airway resistance, elastance and compliance, the work of breathing and ventilation/perfusion relationships including hypoxic pulmonary vasoconstriction. General anaesthesia has profound effects on the respiratory system including the ventilatory response to hypercapnia and hypoxia, upper airway muscle function, lung volumes and ventilation/perfusion matching. Many surgical procedures are facilitated by one-lung ventilation. When utilizing one-lung ventilation a key aim for the anaesthetist is to maintain adequate alveolar ventilation while minimizing the amount of shunt through the non-ventilated lung. A detailed understanding of one-lung ventilation is therefore vital if a logical approach to management is to be adopted.     

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.