Different positive end expiratory pressure and tidal volume controls on lung protection and inflammatory factors during surgical anesthesia

BACKGROUND Mechanical ventilation can lead to the severe impairment of the metabolic pathway of alveolar surfactants,inactivating alveolar surfactants and significantly reducing lung-chest compliance.The cardiopulmonary function of elderly patients usually reduced to a certain extent,and there are lung complications after surgical anesthesia,just like lung barotrauma caused by mechanical ventilation,atelectasis and postoperative hypoxemia.AIM To investigate the effects of different positive end expiratory pressures(PEEPs)and tidal volumes(VTs)on respiratory function,the degree of the inflammatory response and hemodynamic indexes in patients undergoing surgery under general anesthesia.METHODS A total of 120 patients undergoing surgery for gastric or colon cancer under general anesthesia in Xinghua People's Hospital from January 2017 to January 2021 were randomly divided into Group A and Group B,with 60 cases in each group.The ventilation mode in Group A was VT(6.0 mL/kg)+PEEP(5.0 cmH_(2)O),while that in Group B was VT(6.0 mL/kg)+PEEP(8.0 cmH_(2)O).Blood gas parameters,respiratory mechanical parameters,inflammatory response indicators,hemodynamic indicators and related complications were compared between the two groups.RESULTS There were no significant differences in PaCO_(2),PaO_(2),oxygen or the examined indexes at T0 between group A and group B(P>0.05).The measured PaO_(2) value of patients in group A at T3 was higher than that in group B,and the difference was significant(P<0.05).There were no significant differences in peak airway pressure(P_(peak)),mean airway pressure or dynamic pulmonary compliance(Cdyn)at T0 between group A and group B(P>0.05).The measured P_(peak) value of patients in group A at T1 was higher than that in group B,and the difference was significant(P<0.05).The measured Cdyn value at T1 and T2 was greater than that in group B(P<0.05).Before surgery,there were no significant differences in tumor necrosis factor-α(TNF-α),interleukin(IL)-6 or IL-10 between group A and group B(P>0.05).After 4 h,the measured values of TNF-αand IL-6 in group A were lower than those in group B,and the differences were significant(P<0.05).The IL-10 Level in group A was higher than that in group B(P<0.05).At T0,there were no significant differences in cardiac output,cardiac index(CI),stroke volume index(SVI)or mean arterial pressure between group A and group B(P>0.05).The measured values of CI and SVI at T2 in patients in group A were higher than those in group B,and the differences were significant(P<0.05).CONCLUSION For patients undergoing surgery for gastric or colon cancer under general anesthesia,the VT(6.0 mL/kg)+PEEP(5.0 cmH_(2)O)regimen was more effective than the VT(6.0 mL/kg)+PEEP(8.0 cmH_(2)O)regimen in protecting the lung function and ventilatory function of patients,and it had better effects on maintaining hemodynamic stability and reducing inflammatory reactions.

Effects of extrinsic positive end-expiratory pressure on cardiopulmonary function in patients with chronic obstructive pulmonary disease

Objective To choose one optimal extrinsic positive end-expiratory pressure (PEEPe) for ventilated patients with chronic obstructive pulmonary disease (COPD) and to compare two methods for choosing the optimal level of PEEPe.Methods Ten ventilated patients with COPD were included in the study. First, static intrinsic positive end-expiratory pressure (PEEPi,st) was measured when PEEPe was zero, and the PEEPi,st was called PEEPi,stz. PEEPe at 0%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of PEEPi,stz, respectively, were applied randomly. Respiratory mechanics, hemodynamics, and oxygen dynamics were recorded 30 minutes after the level of PEEPe was changed.Results When PEEPe was not higher than 80% of PEEPi,stz, no measurement changed significantly. When PEEPe was increased to 90% and 100% of PEEPi,stz, PEEPi,st, peak inspiratory pressure, plateau pressure, pulmonary capillary wedge pressure and central venous pressure increased significantly, P<0.01. Cardiac output and left ventricular work index decreased significantly, P<0.01. Oxygen delivery decreased significantly, P<0.05. When PEEPe was increased to 100% of PEEPi,stz, the right ventricular work index decreased significantly, P<0.05.Conclusion Eighty percent of PEEPi,stz was the upper limit of PEEPe. The results of the two methods used to set the level of PEEPe were identical.

Effects of extrinsic positive end-expiratory pressure on work of breathing in patients with chronic obstructive pulmonary disease

Objective To investigate the effects of extrinsic positive end-expiratory pressure (PEEPe) on work of breathing in patients with chronic obstructive pulmonary disease (COPD) and their corresponding mechanism.Methods Ten ventilated patients with COPD were included in the study. A Bicore CP-100 pulmonary monitor (Bicore Monitoring System, USA) was used for monitoring respiratory mechanics. First, dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn) was measured when PEEPe was zero, which was called PEEPi,dynz. Then the PEEPe was set randomly at 0%, 40%, 60%, 80% and 100% of PEEPi,dynz respectively. Pulmonary mechanics and other parameters (heart rate, blood pressure and blood gas analysis) were measured 30 minutes after the level of PEEPe was changed.Results Work of breathing patient (WOBp), pressure time product, difference of esophageal pressure and PEEPi,dyn decreased significantly when PEEPe was applied, and continued decreasing as PEEPe was increased. Work of breathing ventilator increased significantly when PEEPe was increased to 80% and 100% of PEEPi,dynz. Significantly positive linear correlation was found between the changes in WOBp and in PEEPi,dyn.Conclusions WOBp decreases gradually as PEEPe is increased. WOBp decreases by narrowing the difference between the alveolus pressure and the central airway pressure at the end of expiration when PEEPe is applied.

Positive End-expiratory Pressure Titration after Alveolar Flecruitment Directed by Electrical Impedance Tomography

Background： Electrical impedance tomography （EIT） is a real-time bedside monitoring tool, which can reflect dynamic regional lung ventilation. The aim of the present study was to monitor regional gas distribution in patients with acute respiratory distress syndrome （ARDS） during positive-end-expiratory pressure （PEEP） titration using EIT. Methods： Eighteen ARDS patients under mechanical ventilation in Department of Critical Care Medicine of Peking Union Medical College Hospital from January to April in 2014 were included in this prospective observational study. After recruitment maneuvers （RMs）, decremental PEEP titration was performed from 20 cmH20 to 5 cmH20 in steps of 3 cmH20 every 5-10 min. Regional over-distension and recruitment were monitored with EIT. Results： After RMs, patient with arterial blood oxygen partial pressure （PaO2） ＋ carbon dioxide partial pressure （PaCO2） 〉400 mmHg with 100% of fractional inspired oxygen concentration were defined as RM responders. Thirteen ARDS patients was diagnosed as responders whose PaO2 ＋ PaCO2, were higher than nonresponders （419 ± 44 mmHg vs. 170 ±73 mmHg, P 〈 0.0001）. In responders, PEEP mainly increased-recruited pixels in dependent regions and over-distended pixels in nondependent regions. PEEP alleviated global inhomogeneity of tidal volume and end-expiratory lung volume. PEEP levels without significant alveolar derecruitment and over-distension were identified individually. Conclusions： After RMs, PEEP titration significantly affected regional gas distribution in lung, which could be monitored with EIT. EIT has the potential to optimize PEEP titration.

Effects of different levels of end-expiratory positive pressure on lung recruitment and protection in patients with acute respiratory distress syndrome

Background It is still controversial as to the implementation of higher positive end-expiratory pressure （PEEP） in patients with acute respiratory distress syndrome （ARDS）. This study was conducted to compare the lower and higher PEEP in patients with ARDS ventilated with low tidal volume, to investigate the relationship between the recruited lung volume by higher PEEP and relevant independent variables and to provide a bedside estimate of the percentage of potentially recruitable lung by higher PEEP. Methods Twenty-four patients with ARDS were studied. A lung recruiting maneuver was performed, then each patient was ventilated with PEEP of 8 cmH20 for 4 hours and subsequently with PEEP of 16 cmH20 for 4 hours. At the end of each PEEP level period, gas exchange, hemodynamic data, lung mechanics, stress index ＂b＂ of the dynamic pressure-time curve, intrinsic PEEP and recruited volume by PEEP were measured. Results Fourteen patients were recruiters whose alveolar recruited volumes induced by PEEP 16 cmH20 were （425_＋65） ml and 10 patients were non-recruiters. Compared with the PEEP 8 cmH20 period, after the application of the PEEP 16 cmH20, the PaO2/FiO2 ratio and static lung compliance both remained unchanged in non-recruiters, whereas they increased significantly in recruiters. Changes in PaO2/FiO2 and static lung compliance after PEEP increase were independently associated with the alveolar recruitment. Analyzing the relationship between recruiting maneuver （RM）-induced change in end-expiratory lung volume and the alveolar recruitment induced by PEEP, we found a notable correlation. Conclusions The results of this study indicated that the potential for alveolar recruitment might vary among the ARDS population and the higher PEEP levels should be limited to recruiters. Improving in PaO2/FiO2, static lung compliance after PEEP increase and the shape of the pressure-time curve could be helpful for PEEP application.

Alveolar stability under different combinations of positive end-expiratory pressure and tidal volume： alveolar microscopy in isolated injured rat lungs

Background High positive end-expiratory pressure （PEEP） and low tidal volume （VT） ventilation is thought to be a protective ventilation strategy. It is hypothesized that the stabilization of collapsible alveoli during expiration contributes to lung protection. However, this hypothesis came from analysis of indirect indices like the analysis of the pressure-volume curve of the lung. The purpose of this study was to investigate isolated healthy and injured rat lungs by means of alveolar microscopy, in which combination of PEEP and VT is beneficial with respect to alveolar stability （I-E%）. Methods Alveolar stability was investigated in isolated, non-perfused mechanically ventilated rat lungs. Injured lungs were compared with normal lungs. For both groups three PEEP settings （5, 10, 20 cmH20） were combined with three VT settings （6, 10, 15 ml/kg） resulting in nine PEEP-VT combinations per group. Analysis was performed by alveolar microscopy. Results In normal lungs alveolar stability persisted in all PEEP-VT combinations （I-E% （3.2±11.0）%）. There was no significant difference using different settings （P 〉0.01）. In contrast, alveoli in injured lungs were extremely instable at PEEP levels of 5 cmH20 （mean I-E% 100%） and 10 cmH2O （mean I-E% （30.7±16.8）%）; only at a PEEP of 20 cmH20 were alveoli stabilized （mean I-E% of （0.2±9.3）%）. Conclusions In isolated healthy lungs alveolar stability is almost unaffected by different settings of PEEP and VT. In isolated injured lungs only a high PEEP level of 20 cmH2O resulted in stabilized alveoli whereas lower PEEP levels are associated with alveolar instability.

不同通气模式对Trendelenburg体位腹腔镜手术患者PaO_2和PaCO_2的影响

目的探讨压力控制通气（PCV）联合呼气末正压（PEEP）在Trendelenburg体位腹腔镜手术中对PaO_2和PaCO_2的影响。方法腹腔镜直肠癌根治术患者40例,年龄35~55岁,随机分为两组,每组20例。A组采用容量控制通气模式（VCV）通气[VT=体重（kg）×10ml]20min后,改用PCV模式通气20min,返回VCV模式继续通气20min后,采用PCV＋低PEEP（5cm H_2O）模式通气20min。B组则将PCV与PCV＋PEEP的顺序调换。在切换通气模式时行动脉血气分析。结果两组VCV模式时PaO_2均明显低于PCV模式及PCV＋PEEP模式（P〈0.05）。PCV模式时PaO_2明显低于PCV＋PEEP模式（P〈0.05）;VCV模式时PaCO_2明显高于PCV模式和PCV＋PEEP模式（P〈0.05）,而PCV模式和PCV＋PEEP模式时PaCO_2差异无统计学意义。VCV模式时动脉血pH值明显低于PCV和PCV＋PEEP模式（P〈0.05）,PCV和PCV＋PEEP模式时动脉血pH值差异无统计学意义。结论 Trendelenburg体位腹腔镜手术时采用PCV＋PEEP通气模式,与单纯VCV或单纯PCV模式比较,在提高PaO_2以及降低PaCO_2方面更具优势。

不同水平呼气末正压对腹腔镜下肝部分切除术患者中心静脉压的影响

目的:探讨不同水平呼气末正压(PEEP)对行腹腔镜下肝部分切除术患者中心静脉压(CVP)的影响。方法:选取福建医科大学附属漳州市医院2021年11月~2022年11月收治的行腹腔镜下肝部分切除术患者81例作为研究对象,根据术中使用不同的PEE P值进行分组:A组(n=27)实施小潮气量6 ml/kg理想体重(PBW),PEEP 0 cmH_(2)O的通气模式;B组(n=27)实施小潮气量6 ml/kg PBW,PEEP 0 cmH_(2)O的通气模式;C组(n=27)实施小潮气量6 ml/kg PBW,PEEP 8 cmH_(2)O的通气模式。分别记录并比较三组不同体位时间点[插管后平卧位(T0)、气腹后平卧位(T1)、气腹后反特伦德伦伯体位(T2)、手术结束后平卧位(T3)]的CVP、平均动脉压(MAP)以及气道峰压;比较三组术中出血量、红细胞输注量与血浆输注量;观察并比较三组围术期的不良反应发生情况。结果:三组T0、T3之间的CVP比较差异无统计学意义(P>0.05),T1、T2时,A组的CVP低于B组、B组低于C组,三组间比较,差异有统计学意义(P<0.05);三组在T0、T1、T2、T3时的MAP比较差异无统计学意义(P>0.05),A组在T0、T1、T2时的气道峰压低于B组,B组低于C组,三组间比较,差异有统计学意义(P<0.05);T3时的气道峰压比较差异无统计学意义(P>0.05);三组术中出血量、红细胞输注量与血浆输注量比较,差异无统计学意义(P>0.05);B组的不良反应发生率低于A组、C组,差异有统计学意义(P<0.05)。结论:在腹腔镜下肝部分切除术中实施PEEP 4 cmH_(2)O的通气模式,功效更为积极,能够一定程度上稳定患者术中的CVP,有利于降低或防止不良反应的发生。

Trendelenburg体位和呼气末正压对喉罩全身麻醉患者颈内静脉横截面积的影响

目的探讨呼气末正压(PEEP)、Trendelenburg体位及两者联合应用对喉罩全身麻醉患者颈内静脉横截面积(CSA)的影响。方法择期喉罩全身麻醉患者60例,随机分为4组:PEEP 0 cm H_2O(1 cm H_2O≈98 Pa,P0组)、Trendelenburg体位(T组)、PEEP 10 cm H_2O(P10组)和Trendelenburg体位联合PEEP 10 cm H_2O(C组)。患者先后于4个分组方案下接受右侧颈部超声检查,记录各个分组的颈内静脉CSA、平均动脉压(MAP)、心率(HR)和血管活性药使用次数。结果所有患者的右侧颈内静脉清晰可见。与P0组相比,T组、P10组和C组患者颈内静脉CSA均有增加(均<0.01);与C组比较,P10组颈内静脉CSA显著减小(<0.05)。4组MAP差异有统计学意义(<0.05),与P0组比较,C组MAP降低(<0.05)。结论 10 cm H_2O PEEP和Trendelenburg体位均能显著增加喉罩全身麻醉患者右侧颈内静脉CSA,联合应用可能影响循环稳定。

PEEP阶梯改变方向对Trendelenburg体位腔镜手术病人个体化PEEP确定及肺部并发症的影响

目的:比较呼气末正压(PEEP)阶梯改变方向及改变过程中每个PEEP水平持续时间的不同对Trendelenburg体位腔镜手术中病人个体化PEEP的确定及肺部动态顺应性和氧合情况的影响。方法:选取择期全麻下行腔镜下结直肠手术病人60例,根据术中PEEP改变方向的不同随机分为递增组和递减组,各30例。递增组病人PEEP从0 cmH_(2)O开始递增至16 cmH_(2)O,递减组由16 cmH_(2)O开始递减至0 cmH_(2)O,所有病人PEEP变化梯度均为2 cmH_(2)O。记录PEEP变化过程中每个PEEP水平下1 min和2 min时麻醉机所显示呼气末的动态肺顺应性(Cdyn),将Cdyn最大时的PEEP定为该方法所获取的个体化PEEP。在PEEP改变过程中,若有创平均动脉压下降>10%基础水平,则给予去氧肾上腺素以维持血流动力学稳定。结果:2组在维持血流动力学稳定过程中需要给予去氧肾上腺素的病人数差异无统计学意义(P>0.05)。2组病人PEEP阶梯前后PaO_(2)/FiO_(2)差异均无统计学意义(P>0.05);递增组病人PEEP阶梯前后PaO_(2)/FiO_(2)差异无统计学意义(P>0.05),递减组病人PEEP阶梯后PaO_(2)/FiO_(2)高于阶梯前(P<0.05)。2组PEEP维持1 min和维持2 min所获取的个体化PEEP差异均无统计学意义(P>0.05)。在PEEP维持时间为1 min,其水平为12、14和16 cmH_(2)O时,以及维持时间为2 min,PEEP水平为8、10、12和14 cm H_(2)O时,递减组Cdyn均明显高于递增组(P<0.01)。结论:在病人接受Trendelenburg体位腔镜手术中,PEEP呈阶梯式递增或递减对个体化PEEP的确定和对循环的影响相同,且每个PEEP水平持续1 min或2 min其结果无明显差异;但PEEP递减在PEEP阶梯变化过程中对肺复张的作用相对于递增更加有效和迅速。

Anesthetic management of the SRS^(TM) endoscopic stapling system for gastro-esophageal reflux disease

The SRS TM Endoscopic Stapling System(Medigus,Tel Aviv,Israel) is a new tool capable of creating a totally endoscopic fundoplication,combined with an endoscope,endoscopic ultrasound and a surgical stapler.SRS TM endoscopic stapling for gastro-esophageal reflux disease is a minimally invasive,outpatient procedure,which requires general anesthesia with positive-pressure ventilation.Keeping the patient on positive endexpiratory pressure(PEEP) may minimize the pressure gradient between the esophagus and the mediastinum,as well as help to prevent air from leaking around the screws and causing pneumomediastinum.In addition,in patients with hiatal hernia,higher PEEP levels may be required to increase intra-thoracic pressure and to force the stomach to slide into the abdomen for ease of endoscopy.We advise smoother emergence from anesthesia,taking precautions for retching,postoperative nausea and vomiting(PONV),while coughing and gagging during extubation and PONV may affect the success of the procedure.Total intravenous anesthesia with propofol and remifentanil seems to be a good choice for these reasons.

肺保护性通气策略对Trendelenburg体位腹腔镜手术患者呼吸力学及肺功能的影响

目的肺保护性通气策略对Trendelenburg体位腹腔镜手术患者呼吸力学及肺功能的影响。方法选择河南省舞阳县人民医院普外科2020年06月-2021年06月全麻下Trendelenburg体位行腹腔镜下直肠癌根治术患者40例作为研究对象,按随机数表法分为常规机械通气组(N组)和试验组(P组)两组,每组各20例。N组采用常规机械通气参数,P组在气管插管完成后、人工二氧化碳气腹开始前首先进行肺复张策略,而后设定容量控制模式通气参数。分别于气管插管后气腹和体位变动前5分钟(T_(0))、气腹头低脚高位10分钟(T_(1))、气腹头低脚高位30分钟(T_(2))、气腹头低脚高位60分钟(T_(3))、气腹结束即刻(T_(4))、拔除气管导管前5分钟(T5)记录气道峰压(P_(peak))、平均气道压(P_(mean)),计算动态肺顺应性(C_(dyn))。同时于T_(0)、T_(2)、T_(3)、T5各时点采集桡动脉血样行血气分析,记录PaCO_(2)、PaO_(2),计算氧合指数(PaO_(2)/FiO_(2))、呼吸指数(RI)、死腔率(VD/VT)和肺泡-动脉血氧分压差(A-aDO_(2))。记录术后48小时内患者低氧血症和高碳酸血症等并发症发生情况。结果两组患者T_(1)-T_(4)时P_(mean)、P_(peak)水平明显高于T_(0)时,Cdyn明显低于T_(0)时,差异有统计学意义(P<0.05);P组患者T_(1)-T_(4)时Pmean、Ppeak水平明显低于N组,Cdyn明显高于N组,差异有统计学意义(P<0.05);两组患者T_(2)、T_(3)时PaO_(2)/FiO_(2)水平明显低于T_(0)时,A-aDO_(2)、RI和VD/VT明显高于T_(0)时,差异有统计学意义(P<0.05);P组患者T_(0)、T_(2)、T_(3)时PaO_(2)/FiO_(2)水平明显高于N组,A-aDO_(2)、RI和VD/VT明显低于N组,差异有统计学意义(P<0.05);两组患者术后48 h内患者低氧血症、高碳酸血症、肺不张、新出现肺部啰音等并发症发生率比较,差异无统计学意义(P>0.05)。结论低潮气量联合呼气末正压(5 cmH2O)可改善Trendelenburg体位腹腔镜手术患者的呼吸力学和肺功能。

基于驱动压的肺保护性通气策略在婴儿单肺通气中的应用效果

目的探讨基于驱动压(Pd)个体化调节呼气末正压(PEEP)的保护性通气策略在婴儿单肺通气(OLV)中的临床效果。方法60例择期胸腔镜手术婴儿随机分成对照组(C组)和驱动压力组(DP组),每组30例。于OLV期间,比较两组婴儿人工气胸前(T0)、人工气胸后10 min(T_(1))、人工气胸后30 min(T_(2))、人工气胸后60 min(T_(3))和人工气胸结束(T4)时的MAP、HR、潮气量(Vt)、PEEP、Pd、气道峰压(Ppeak),肺静态顺应性(Cs),以及人工气胸前后的动脉血气分析结果。结果两组患儿在各时间点上的MAP、HR和Vt均差异无统计学意义(P>0.05)。与T0相比,两组患儿在T_(1)、T_(2)和T_(3)时的Pd和Ppeak均升高,Cs降低(P<0.05),在T_(2)时的Pa O_(2)和OI降低,Pa CO_(2)升高(P<0.05)。与C组相比,DP组在T_(1)、T_(2)和T_(3)时的Pd和Ppeak更低,PEEP和Cs更高(P<0.05),在T_(2)时Pa O_(2)和OI更高(P<0.05),Pa CO_(2)和FiO_(2)无明显差异(P>0.05)。OLV期间,DP组需要通气补救2例(6.9%)低于C组9例(32.4%)(P<0.05)。两组患儿术后并发症差异无统计学意义(P>0.05)。结论基于驱动压的肺保护性通气策略可个体优化婴儿OLV中PEEP设置,改善通气侧肺部顺应性和氧合。

Arterial and End-Tidal Carbon Dioxide in Supine Obese Patients during General Anesthesia

Background: We investigated the differences between partial pressure of arterial carbon dioxide and end-tidal carbon dioxide (P(a-ET)CO2) with respect to the Broca-Katsura index (BKI), which is an obesity index, in obese patients during general anesthesia. Materials and Methods: From January 2003 to December 2013, we studied 601 patients aged 16 years old or over undergoing general anesthesia. Patients had American Society of Anesthesiology physical status I and II and we reviewed their anesthetic charts. The P(a-ET)CO2 with respect to the BKI divided patients into two groups: 16 to 2 values between the two groups. Results: In patients aged 16 to 2 was 2.2 ± 3.1 mmHg at BKI 2 was 3.2 ± 4.1 mmHg at BKI 2 tends to increase in obese patients during general anesthesia with increasing BKI in patients aged 16 to < 65 years old.

肺复张在急性A型主动脉夹层术后低氧血症中的应用

目的 探讨肺复张治疗急性A型主动脉夹层(acute type A aortic dissection,ATAAD)术后低氧血症的疗效及安全性。方法 选取2019年11月至2022年5月广西医科大学第一附属医院ATAAD术后低氧血症患者56例,将其随机分为肺复张组(n=36)及常规治疗组(n=20)。常规治疗组患者在肺保护性通气基础上行常规机械通气,肺复张组患者采用呼气末正压通气(positive end expiratory pressure,PEEP)递增法进行肺复张。比较两组患者治疗前后的动脉血气分析、呼吸力学指标、血流动力学指标和血清白细胞介素(interleukin,IL)-6及IL-10水平。结果 治疗后12h、24h,两组患者的动脉血氧分压(arterial partial pressure of oxygen,PaO_(2))、氧合指数(oxygenation index,OI)、肺静态顺应性(C_(stat))及肺动态顺应性(C_(dyn))均显著高于本组治疗前,肺泡动脉氧分压差[PO_(2)(A-a)]、呼吸指数(respiratory index,RI)、气道峰压(P_(peak))及气道平台压(P_(plat))均显著低于本组治疗前(P<0.05);肺复张组患者的PaO_(2)、OI、C_(stat)及C_(dyn)均显著高于常规治疗组,PO_(2)(A-a)、RI、P_(peak)及P_(plat)均显著低于常规治疗组(P<0.05)。肺复张组患者肺复张过程中收缩压及平均动脉压有所下降(P<0.05),中心静脉压有所升高(P<0.05),肺复张结束后均恢复至基线水平。治疗后12h,两组患者的血清IL-6和IL-10水平均显著低于本组治疗前(P<0.05)。结论 PEEP递增法肺复张可改善ATAAD术后低氧血症患者的氧合及肺顺应性,但对血流动力学存在一过性影响,治疗时应进行严密监测。

电阻抗断层成像指导机械通气呼吸末正压设置的研究进展

目前机械通气设置最佳呼气末正压(PEEP)的策略仍需要进一步临床探索,电阻抗断层成像(EIT)是20世纪末新发展的临床技术,能够实时监测肺通气等,有助于临床应用来探索最佳PEEP的设置。本综述重点总结了近几年发表的使用EIT指导PEEP设定的原理,通过监测呼吸系统顺应性、空间分布、时间分布、局部肺灌注等信息设定PEEP,以及分析了用此方法设定PEEP的效果和/或使用EIT进行个体化PEEP设置的相关基础与临床研究信息。

不同潮气量和PEEP对脉搏轮廓法与经肺热稀释法测量巴马猪心排血量的影响

【目的】探究机械通气时不同潮气量和呼气末正压(PEEP)对脉搏轮廓法与经肺热稀释法测量巴马猪心排血量的影响。【方法】选取实验用巴马猪12只,随机分为对照组(肺动脉导管热稀释法)、研究组A(经肺热稀释法)和研究组B(脉搏轮廓法),各4只。建立模型,采用不同方法测量心排出量,分析其一致性,比较不同潮气量和PEEP对心排出量的影响。【结果】脉搏轮廓法与热稀释法测定猪心排血量的相关系数为r=0.754,两者具有正相关性。经肺热稀释法与热稀释法测定猪心排血量的相关系数为r=0.771,两者具有正相关性。脉搏轮廓法、与热稀释法测定猪心排血量相对误差为13.5%,两者具有一致性。经肺热稀释法与热稀释法测定猪心排血量相对误差为12.9%,两者具有一致性。随着潮气量增加,心排出量值明显降低,差异具有统计学意义(P<0.05)。随着PEEP增加,猪心排出量明显降低,差异具有统计学意义(P<0.05)。【结论】脉搏轮廓法、经肺热稀释法与热稀释法测定猪心排血量的一致性良好;当机械通气潮气量或PEEP增加时猪心排血量逐渐下降。

肺动态顺应性指导个体化呼气末正压通气对老年患者腹腔镜结直肠癌术中肺功能的影响

目的观察肺动态顺应性(Cdyn)指导个体化呼气末正压通气(PEEP)对老年患者腹腔镜结直肠癌术中肺功能的影响。方法选择择期行腹腔镜结直肠癌根治术的老年患者68例,男37例,女31例,年龄65~79岁,BMI<30 kg/m^(2),ASAⅡ或Ⅲ级。采用随机数字表法将患者分为两组:个体化PEEP组(P组)和对照组(C组),每组34例。P组在插管完成即刻、气腹-屈氏体位建立即刻、气腹结束即刻行肺复张及PEEP滴定试验,C组设置固定PEEP 5 cmH_(2)O。记录P组3次滴定时最佳PEEP和实际VT。记录气管插管完成后10 min(T_(1))、气腹-屈氏体位建立后10 min(T_(2))、60 min(T_(3))、手术结束拔管前(T_(4))PaO_(2)、PaCO_(2)、PETCO_(2),计算氧合指数(OI)、死腔/潮气量比值(Vd/VT)、肺泡-动脉血氧分压差(A-aDO_(2))、驱动压和Cdyn。采用ELISA法测定麻醉诱导前(T0)、拔管后10 min(T5)的白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)、肺Clara细胞分泌蛋白(CC16)及肺泡表面活性物质-D(SP-D)的浓度。记录术后肺部并发症(PPCs)的发生情况。结果P组滴定最佳PEEP的中位数为4 cmH_(2)O。与C组比较,P组T_(4)时PaO_(2)、OI明显升高,T_(1)、T_(3)、T_(4)时Cdyn明显升高,T_(1)—T_(4)时驱动压明显降低,T5时CC16血清浓度明显降低(P<0.05)。两组T_(1)—T_(4)时PaCO_(2)、PETCO_(2)、A-aDO_(2)、Vd/VT差异无统计学意义。两组术后3 d均未发生严重PPCs。结论在老年患者腹腔镜结直肠癌根治术中,采用压力控制通气下肺动态顺应性指导个体化PEEP的肺保护通气策略,可提高患者术中肺动态顺应性,降低驱动压,改善手术结束时氧合,降低术后CC16血清浓度,改善术中肺功能。

个体化PEEP联合定期肺复张对行腹腔镜结直肠癌根治术老年患者术后肺不张的影响

目的评估肺超声下驱动压(ΔP)引导的个体化呼气末正压通气(PEEP)联合定期肺复张对Trendelenburg体位下行腹腔镜结直肠癌根治术的老年患者术后肺不张的影响。方法纳入年龄65~85岁、美国麻醉医师协会分级Ⅰ—Ⅲ级,拟行腹腔镜下结直肠癌根治术的患者62例并分为试验组和对照组(各31例)。2组均在气腹开始后进行第1次肺复张,随后立即以最低ΔP滴定个体化PEEP,气腹结束后进行第2次肺复张。试验组自气腹开始每30 min额外进行一次肺复张,对照组则不干预。以麻醉诱导前(T_(0))、气腹后30 min(T_(1))、气腹后90 min(T_(2))、手术结束时(T_(3))、进入麻醉复苏室(PACU)45 min后(T_(4))为观察记录时间点。记录T_(0)、T_(3)和T_(4)时肺超声评分(LUS);T_(1)—T_(3)时肺动态顺应性(Cdyn);T_(0)—T_(4)时间点氧合指数(OI)、平均动脉压(MAP)、心率(HR);记录肺复张期间低血压、PACU中低氧饱和事件以及术后7 d内肺部并发症(POPC)发生率。结果与对照组相比,试验组在T_(3)和T_(4)时LUS下降(P<0.05),T_(2)、T_(3)时OI和Cdyn升高(P<0.05)。试验组在PACU中低氧饱和事件发生率较对照组下降(P<0.05)。2组患者肺复张期间低血压发生率和术后7 d内POPC发生率差异无统计学意义(P>0.05)。结论个体化PEEP联合定期肺复张可有效减少老年患者腹腔镜结直肠癌根治术后即刻和PACU中的肺不张。

电阻抗断层成像技术用于呼气末正压滴定的研究进展

适当的呼气末正压(PEEP)是保护性肺通气策略的重要组成部分,PEEP可以保持肺泡开放,减少肺萎陷伤。尽管个体化PEEP已被越来越多的临床医师认可,但最佳的PEEP滴定方法尚存争议。电阻抗断层成像(EIT)是一种无创、无辐射的成像技术,可在床边实时动态评估肺功能,将肺通气过程中的阻抗变化以动态图像呈现,能够反映PEEP调整前后肺内通气及气体分布变化,因此,EIT可用于滴定个体化PEEP。本文简要概括EIT的基本原理及监测指标,阐述临床应用EIT指导下的PEEP(PEEP_(EIT))滴定方法,旨在加强对EIT的优点和局限性的理解,为优化个体化PEEP的设置提供参考。