Effect of positive end-expiratory pressure ventilation on central venous pressure and intraoperative blood loss in patients undergoing laparoscopic hepatectomy

Objective:Tto investigate the effects of positive end-expiratory pressure(PEEP)ventilation on central venous pressure(CVP)and intraoperative blood loss in patients undergoing laparoscopic hepatectomy.Methods:46 cases of patients undergoing laparoscopic hepatectomy,25 cases of male,female 21 cases,ASAⅠ~Ⅲlevel,were randomly divided into two groups.In group A tidal volume was set to 6 ml/kg(Predicted Body Weight,PBW)and PEEP was set to 0 cmH2O.The tidal volume of group B was set as group A,PEEP was set to 8 cmH2O.CVP,MAP,and Ppeak were recorded in the supine position after intubation(T0),supine position after pneumoperitoneal(T1),anti-trendelenberg position after pneumoperitoneal(T2),supine position after surgery(T3),and Ddyn was calculated.The amount of nitroglycerin and the amount of blood loss were recorded.Results:Compared with group A,the CVP of group B was significantly increased at T1 and T2(P<0.05).Compared to T2 with T1 in group A and group B,CVP was decreased significantly(P<0.05).At T3,Cdyn in group B was significantly higher than that in group A(P<0.05).The amount of nitroglycerin in group B was significantly higher than that in group A(P<0.05).There was no significant difference in intraoperative fluid rehydration and blood loss between the two groups(P>0.05).Conclusion:PEEP with 8cmH2O can improve Ddyn in patients undergoing laparoscopic hepatectomy,but increased CVP.It requires more use of controlled low central venous pressure techniques to reduce intraoperative blood loss.

Role of proning and positive end-expiratory pressure in COVID-19

The novel coronavirus,which was declared a pandemic by the World Health Organization in early 2020 has brought with itself major morbidity and mortality.It has increased hospital occupancy,heralded economic turmoil,and the rapid transmission and community spread have added to the burden of the virus.Most of the patients are admitted to the intensive care unit(ICU)for acute hypoxic respiratory failure often secondary to acute respiratory distress syndrome(ARDS).Based on the limited data available,there have been different opinions about the respiratory mechanics of the ARDS caused by coronavirus disease 2019(COVID-19).Our article provides an insight into COVID-19 pathophysiology and how it differs from typical ARDS.Based on these differences,our article explains the different approach to ventilation in COVID-19 ARDS compared to typical ARDS.We critically analyze the role of positive end-expiratory pressure(PEEP)and proning in the ICU patients.Through the limited data and clinical experience are available,we believe that early proning in COVID-19 patients improves oxygenation and optimal PEEP should be titrated based on individual lung compliance.

Driving pressure in mechanical ventilation:A review

Driving pressure(ΔP)is a core therapeutic component of mechanical ventilation(MV).Varying levels ofΔP have been employed during MV depending on the type of underlying pathology and severity of injury.However,ΔP levels have also been shown to closely impact hard endpoints such as mortality.Considering this,conducting an in-depth review ofΔP as a unique,outcome-impacting therapeutic modality is extremely important.There is a need to understand the subtleties involved in making sureΔP levels are optimized to enhance outcomes and minimize harm.We performed this narrative review to further explore the various uses ofΔP,the different parameters that can affect its use,and how outcomes vary in different patient populations at different pressure levels.To better utilizeΔP in MV-requiring patients,additional large-scale clinical studies are needed.

Effects of positive end-expiratory pressure on intracranial pressure,cerebral perfusion pressure,and brain oxygenation in acute brain injury:Friend or foe?A scoping review

Background Patients with acute brain injury(ABI)are a peculiar population because ABI does not only affect the brain but also other organs such as the lungs,as theorized in brain–lung crosstalk models.ABI patients often require mechanical ventilation(MV)to avoid the complications of impaired respiratory function that can follow ABI;MV should be settled with meticulousness owing to its effects on the intracranial compartment,especially regarding positive end-expiratory pressure(PEEP).This scoping review aimed to(1)describe the physiological basis and mechanisms related to the effects of PEEP in ABI;(2)examine how clinical research is conducted on this topic;(3)identify methods for setting PEEP in ABI;and(4)investigate the impact of the application of PEEP in ABI on the outcome.Methods The five-stage paradigm devised by Peters et al.and expanded by Arksey and O'Malley,Levac et al.,and the Joanna Briggs Institute was used for methodology.We also adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)extension criteria.Inclusion criteria:we compiled all scientific data from peer-reviewed journals and studies that discussed the application of PEEP and its impact on intracranial pressure,cerebral perfusion pressure,and brain oxygenation in adult patients with ABI.Exclusion criteria:studies that only examined a pediatric patient group(those under the age of 18),experiments conducted solely on animals;studies without intracranial pressure and/or cerebral perfusion pressure determinations,and studies with incomplete information.Two authors searched and screened for inclusion in papers published up to July 2023 using the PubMed-indexed online database.Data were presented in narrative and tubular form.Results The initial search yielded 330 references on the application of PEEP in ABI,of which 36 met our inclusion criteria.PEEP has recognized beneficial effects on gas exchange,but it produces hemodynamic changes that should be predicted to avoid undesired consequences on cerebral blood flow and intracranial pressure.Moreover,the elastic properties of the lungs influence the transmission of the forces applied by MV over the brain so they should be taken into consideration.Currently,there are no specific tools that can predict the effect of PEEP on the brain,but there is an established need for a comprehensive monitoring approach for these patients,acknowledging the etiology of ABI and the measurable variables to personalize MV.Conclusion PEEP can be safely used in patients with ABI to improve gas exchange keeping in mind its potentially harmful effects,which can be predicted with adequate monitoring supported by bedside non-invasive neuromonitoring tools.

Influence of positive end-expiratory pressure upregulation on the right ventricle in critical patients with acute respiratory distress syndrome:an observational cohort study

Background This study aimed to investigate the influence of positive end-expiratory pressure(PEEP)on the right ventricle(RV)of mechanical ventilation-assisted patients through echocardiography.Methods Seventy-six patients assisted with mechanical ventilation were enrolled in this study.Positive end-expiratory pressure was upregulated by 4 cm H_(2)O to treat acute respiratory distress syndrome,wherein echocardiography was performed before and after this process.Hemodynamic data were also recorded.All variables were compared before and after PEEP upregulation.The effect of PEEP was also evaluated in patients with and without decreased static lung compliance(SLC).Results Positive end-expiratory pressure upregulation significantly affected the RV function.Remarkable differences were observed in the following:Tei index(P=0.027),pulmonary artery pressure(P=0.039),tricuspid annular plane systolic excursion(P=0.014),early wave/atrial wave(P=0.002),diaphragm excursion(P<0.001),inferior vena cava collapsing index(P<0.001),and SLC(P<0.001).There were no significant changes in heart rate,respiratory rate,central venous pressure,mean arterial pressure,and base excess(P>0.05).Furthermore,the cardiac output of the RV was not significantly affected.In patients with decreased SLC(n=41),there were more significant changes in diaphragm excursion(P<0.001),inferior vena cava collapse index(P=0.025),pulmonary artery pressure(P<0.001),and tricuspid annular plane systolic excursion(P=0.007)than in those without decreased SLC(n=35).Conclusion Positive end-expiratory pressure upregulation significantly affected the RV function of critically ill patients with acute respiratory distress syndrome,especially in those with decreased SLC.

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.

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。

驱动压导向的个体化呼气末正压通气对行腹腔镜胃癌根治术老年患者的肺保护作用

目的探讨驱动压导向的个体化呼气末正压(PEEP)通气是否会对行腹腔镜胃癌根治术的老年患者的肺起到保护作用。方法选取择期行腹腔镜胃癌根治术的老年患者64例,按照随机数字表法分为驱动压导向的个体化PEEP组(试验组)和固定PEEP组(对照组),每组32例。对照组PEEP为5 cmH2O;在气腹稳定后,试验组PEEP按照4~16 cmH2O依次递增滴定,每次进行10次呼吸循环并记录各个PEEP值最后1次呼吸循环时的驱动压,滴定结束后选择最低驱动压对应的PEEP持续至拔管。记录插管后5 min(T_(1))、PEEP滴定后即刻(T_(2))、手术开始1 h(T_(3))、手术开始2 h(T_(4))、气腹释放后10 min(T5)时的气道峰压(Ppeak)、气道平台压(Pplat)、PEEP;计算驱动压、肺动态顺应性(Cdyn);记录患者T_(1)-5时的动脉血氧分压(PaO_(2)),计算氧合指数(OI);评估患者术前及术后第1、3、5天的肺功能,记录术后第2天改良临床肺部感染评分(mCPIS)及术后7 d内肺部并发症(PPCs)的发生情况。结果与T_(1)时比较,T_(2-5)时2组Ppeak、Pplat、驱动压均升高、Cdyn均降低,T_(4)时对照组OI降低(P<0.05)。与对照组比较,T_(2-5)时试验组Ppeak、Pplat、Cdyn升高,驱动压降低,T_(3)-5时OI升高(P<0.05)。与术前比较,术后1 d、3 d、5 d 2组FVC均降低,术后1 d、3 d2组FEV1、最大呼气流量(PEF)均降低(P<0.05)。与对照组比较,试验组术后1 d用力肺活量(FVC)、FEV1、PEF升高(P<0.05)。与术前比较,2组患者术后第2天mCPIS评分升高(P<0.05);与对照组比较,试验组术后第2天mCPIS评分降低(P<0.05)。术后7 d内试验组PPCs发生率低于对照组(15.6%vs.40.6%)。结论驱动压导向的个体化PEEP可提高肺顺应性,改善氧合功能和术后早期肺功能,并降低驱动压及术后肺部并发症的发生。

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。

Effect of neurally adjusted ventilatory assist on trigger of mechanical ventilation in acute exacerbation of chronic obstructive pulmonary disease patients with intrinsic positive end-expiratory pressure

Objective To compare the trigger delay and work of trigger between neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV) in acute exacerbation of chronic obstructive pulmonary disease(AECOPD) patients with intrinsic positive end-expiratory pressure (PEEP) during mechanical ventilation.

基于肺超声评分评估驱动压导向呼气末正压个体化动态滴定对老年腹腔镜结直肠癌根治术患者术后肺不张的影响

目的探讨肺超声评估驱动压导向呼气末正压(PEEP)个体化动态滴定在老年腹腔镜结直肠癌根治术患者中的应用效果,并使用肺超声评分评估肺不张的发生情况。方法根据PEEP滴定的不同将60例于2021年4月至2023年4月期间在医院接受腹腔镜结直肠癌根治术治疗的老年患者分为实施5 CMH2O固定PEEP的对照组(N=30)和实施驱动压导向个体化动态PEEP的试验组(N=30)。比较两组肺超声评分、肺不张发生情况、通气力学及肺损伤情况。结果拔管前及拔管后30 MIN,两组肺超声评分均高于麻醉前,但试验组均低于对照组,同时试验组肺不张发生率低于对照组,差异有统计学意义(P<0.05);PEEP后30 MIN、术毕,两组驱动压、克拉拉细胞蛋白16均高于插管后5 MIN,但试验组均低于对照组,差异有统计学意义(P<0.05)。结论驱动压导向的PEEP个体化动态滴定可减轻老年腹腔镜结直肠癌根治术患者的肺损伤,改善其术中的通气力学,降低其肺超声评分及肺不张发生率。

术中肺保护性通气策略的研究进展

肺保护性通气策略最初用于重症监护室急性呼吸窘迫综合征患者治疗,后来逐渐被麻醉科医师用于术中机械通气的管理,以减少通气引起的肺损伤和术后并发症。近几年的研究中,肺保护性通气策略在多种情况下的安全性及有效性不断得到论证,同时,随着一些新的监测手段如肺部超声、电阻抗等技术的兴起,肺保护性通气策略个体化正在成为一个热门的新兴领域。

Erroneous presentation of respiratory-hemodynamic disturbances and postsurgical inflammatory responses in patients having undergone abdominal cavity cancer surgery

In this letter to the editor,the authors discuss the findings and shortcomings of a published retrospective study,including 120 patients undergoing surgery for gastric or colon cancer under general anesthesia.The study focused on perioperative dynamic respiratory and hemodynamic disturbances and early postsurgical inflammatory responses.

老年泌尿外科手术患者个体化呼气末正压通气对术后肺部并发症效果观察

目的探究老年泌尿外科手术患者麻醉中应用个体化呼气末正压(PEEP)通气预防术后肺部并发症的效果。方法选取2020年10月至2021年10月台州市第一人民医院收治的老年泌尿外科手术患者66例,按照随机数字表法分为气管插管通气组和PEEP通气组,每组33例。气管插管通气组采用常规气管插管全麻模式,PEEP通气组采用个体化PEEP模式。采用肺功能仪检测麻醉前1 h、苏醒后1 h第1秒用力呼气量(FEV1)、用力肺活量(FVC)、FEV1/FVC水平;采用ELISA法检测麻醉前1 h、苏醒后1 h细胞间黏附分子-1(ICAM-1)、表面活性蛋白A(SP-A)、IL-6、IL-8、TNF-α水平;采用简易精神状态评价量表(MMSE)对患者麻醉前1 h、苏醒后1 d认知功能进行评估;观察两组患者术后2~4 d谵妄以及肺炎、肺不张、呼吸衰竭、肺部感染等肺部并发症发生情况。采用炎性因子指标IL-6、IL-8、TNF-α评价两组患者机体炎症反应程度。结果与气管插管通气组比较,PEEP通气组FVC、FEV1、FEV1/FVC、IL-6、IL-8、TNF-α水平以及MMSE评分、谵妄和术后肺部并发症发生率均较低,差异均有统计学意义(均P<0.05)。与气管插管通气组比较,PEEP通气组ICAM-1、SP-A水平较高,差异均有统计学意义(均P<0.05)。结论老年泌尿外科手术患者麻醉中应用个体化PEEP通气可有效预防或减少术后肺部并发症发生。

个体化呼气末正压对肥胖患者腹腔镜子宫附件切除术围手术期的影响

目的探讨驱动压导向个体化呼气末正压(PEEP)对肥胖患者腹腔镜子宫附件切除术围手术期的影响。方法选取2021年8月至2022年8月在中国人民解放军联勤保障部队第九八八医院接受腹腔镜子宫附件切除术的60例肥胖患者,以随机数字表法分为固定PEEP组和驱动压导向个体化PEEP组,各30例。固定PEEP组:在气管插管后,设置5 cmH_(2)O的PEEP持续至手术结束。驱动压导向个体化PEEP组:分别于气管插管、气腹-Trendelenburg体位建立、气腹关闭3个时刻行肺复张后,设置20 cmH_(2)O的PEEP,每10个呼吸循环后以2 cmH_(2)O为间隔,递减至4 cmH_(2)O,滴定过程中驱动压最低对应的PEEP为最佳PEEP,维持该最佳PEEP到下一个时间段。分别记录3次个体化PEEP设置结束后5 min(T_(2)、T_(3)、T_(4))时的驱动压和氧合指数(OI)。于麻醉前(T_(1))和术后24 h(T_(6))测定血清肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)、白介素-12(IL-12)、克拉拉细胞蛋白(CC16)水平,对比T_(1)和手术结束拔出气管导管即刻(T_(5))的肺超声评分(LUS)。结果与T_(2)时相比,两组T_(3)时的驱动压均升高(P<0.05);与T_(3)时相比,T_(4)时的驱动压均下降(P<0.05)。T_(2)~T_(4)时,与固定PEEP组比较,驱动压导向个体化PEEP组OI升高,驱动压降低(P<0.05);相比T_(1)时点,两组T_(5)时LUS升高,驱动压导向个体化PEEP组T_(5)时LUS较固定PEEP组降低,T_(6)时两组血清TNF-α、IL-6、IL-12、CC16水平升高,且驱动压导向个体化PEEP组低于固定PEEP组(P<0.05)。结论驱动压导向个体化PEEP通气策略可改善肥胖患者腹腔镜子宫附件切除术围手术期的肺动态顺应性,提高肺氧合功能,减少炎症介质的释放,降低驱动压和术后LUS。

埃博拉疫情防控正压生物防护服研究

目的 :研究正压生物防护关键技术,研发用于埃博拉个人防护的系列正压生物防护服。方法 :采用聚氨酯双面贴膜研究正压生物防护服复合面料,设计全身式和半身式正压生物防护服结构;采用高性能风机和控制系统,研究电动送风系统;参照相关标准对系列正压生物防护服进行安全性评价。结果:研制的聚氨酯复合面料复合正压生物防护服符合防护要求,研制了系列正压生物防护服,防护服正压差>150 Pa,噪音<70 d B,连续工作时间>4 h,对0.3μm粒径气溶胶整体防护因子>100 000,整体防液体渗透性能满足标准GB 24539—2009要求。结论:研制的系列正压生物防护服可以应用于埃博拉等烈性传染病的医护人员高水平个人防护。

滴定个体化呼气末正压对全麻俯卧位脊柱手术老年患者呼吸功能的影响

目的探讨滴定个体化呼气末正压(PEEP)对全麻俯卧位脊柱手术老年患者术中呼吸和循环的影响。方法选择择期全麻下行俯卧位脊柱手术老年患者80例,男39例,女41例,年龄≥65岁,ASAⅡ或Ⅲ级。根据术中是否滴定获取个体化PEEP将患者随机分为两组:滴定组和对照组,每组40例。滴定组从0 cmH_(2)O开始递增至20 cmH_(2)O,PEEP变化梯度为2 cmH_(2)O获取个体化PEEP;对照组PEEP恒定为5 cmH_(2)O并通气至手术结束。记录滴定过程中每个PEEP水平持续1 min时动态肺顺应性(Cdyn),将Cdyn最大时的PEEP定为个体化PEEP。记录俯卧位时(T_(0))、PEEP通气10 min(T_(1))、30 min(T_(2))、60 min(T_(3))、手术结束(T_(4))、拔管后20 min(T_(5))的MAP、HR、CVP,记录T_(0)—T_(4)时平均气道压(Pmean)和Cdyn。T_(0)—T_(5)时行血气分析,计算肺内分流率(Qs/Qt)和氧合指数(OI)。记录机械通气过程中去氧肾上腺素使用和术后肺部并发症情况。结果滴定组所获取的个体化PEEP为(12.38±2.67)cmH_(2)O。T_(0)—T_(5)时两组MAP、HR、CVP差异无统计学意义。T_(0)—T_(4)时两组Pmean差异无统计学意义。T_(2)—T_(4)时滴定组Cdyn明显高于对照组(P<0.05),Qs/Qt明显低于对照组(P<0.05)。T_(2)—T_(5)时滴定组OI明显高于对照组(P<0.05)。滴定组去氧肾上腺素使用率明显高于对照组[10例(25%)vs 3例(8%),P<0.05]。滴定组术后肺部并发症发生率明显低于对照组[2例(5%)vs 8例(20%),P<0.05]。结论与恒定PEEP 5 cmH_(2)O比较,俯卧位脊柱手术老年患者术中滴定个体化PEEP,能够更好地改善氧合,降低肺内分流率,减少术后肺部并发症。

驱动压导向的个体化呼气末正压通气对腹腔镜手术患者的肺保护作用

目的探讨驱动压导向的个体化呼气末正压(PEEP)通气对腹腔镜手术患者的肺保护作用。方法将40例行择期腹腔镜结直肠癌根治术的患者随机分为试验组(个体化PEEP)和对照组(PEEP 5 cmH_(2)O),每组20例。对照组给予5 cmH_(2)O的PEEP,试验组PEEP按照4、6、8、10、12 cmH_(2)O依次递增滴定,每次进行12次呼吸循环,记录各个PEEP值最后1次呼吸循环时的驱动压,滴定结束后选取产生最低驱动压的PEEP,并持续至拔管。记录2组患者气腹-Trendelenburg体位建立后即刻(T_(0))、PEEP给予后30 min(T_(1))以及术毕(T_(2))的潮气量(VT)、气道峰压(P_(peak))、气道平台压(P_(plat))、PEEP;计算动态肺顺应性(Cdyn);记录患者T_(0)、T_(1)、T_(2)、术后24 h(T_(3))的动脉血氧分压[p a(O_(2))],计算氧合指数(OI);分别于T_(0)、T_(2)、T_(3)采集患者外周静脉血,测定白细胞介素-6(IL-6)、克拉拉细胞蛋白16(CC16)浓度。结果与对照组比较,试验组Cdyn在T_(1)~T_(2)时点增高,OI在T_(1)~T_(3)时点增高,差异有统计学意义(P<0.05);试验组IL-6浓度在T_(2)~T_(3)时点降低,CC16浓度在T_(2)时点降低,差异有统计学意义(P<0.05)。结论驱动压导向的个体化PEEP通气对腹腔镜结直肠癌根治术患者具有肺保护作用。