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.

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.

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.

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.

不同体位及气腹压下脉搏灌注变异指数与每搏量变异度的相关性分析

目的探讨不同体位、气腹压下脉搏灌注变异指数(pleth variability index,PVI)与每搏量变异度(stroke volume variation,SVV)的相关性。方法选取2022年6—12月内蒙古自治区人民医院择期行腹腔镜右半结肠癌根治术的患者60例,全麻后依次在水平位(T1)、Trendelenburg位(T2)、Trendelenburg左倾45°位(T3)3种体位下监测患者HR、MAP、PVI及SVV的变化,并分析不同体位下PVI与SVV的相关性。手术前根据不同气腹压将患者分为A组(10 mmHg)、B组(12 mmHg)和C组(14 mmHg)(1 mmHg=0.133 kPa),每组20例,监测3组不同体位下HR、MAP、PVI及SVV的变化,并分析不同气腹压下PVI与SVV的相关性。结果60例患者中男32例、女28例,平均年龄(53.1±7.7)岁。气腹前,与T1时相比,T2、T3时的HR较低,差异有统计学意义(P<0.05);3种体位下PVI与SVV均存在线性正相关(P<0.05)。气腹后3种体位下,与A组相比,B组、C组的MAP、PVI、SVV均较高;与B组相比,C组HR较低、MAP较高,差异均有统计学意义(P<0.05)。气腹后3种体位下,A组PVI与SVV均呈线性正相关(P<0.05)。结论无气腹状态下,不同体位下PVI与SVV均呈线性正相关。低气腹压(10 mmHg)下,不同体位时PVI与SVV呈线性正相关。体位虽不影响PVI与SVV的正相关性,但超过10 mmHg的气腹压会影响二者的正相关性。

长壁开采覆岩内水平定向长钻孔位置特征与卸压瓦斯抽采机理

长壁采空区卸压瓦斯抽采是煤矿绿色开采技术体系中煤与瓦斯共采的重要组成部分,在覆岩内布置水平定向长钻孔抽采卸压瓦斯近年来应用较多;与高抽巷、普通高位钻孔不同,其在采动覆岩内布置抽采时,对覆岩破坏及瓦斯运移的响应与敏感性具有显著的特殊性。通过理论分析、数值模拟与工程实例验证等方法研究了采动覆岩内水平定向长钻孔的位置特征与卸压瓦斯抽采机理。阐述了水平定向长钻孔抽采卸压瓦斯的技术原理,结合室内试验、数值模拟分析了水平定向长钻孔的3个位置特征:①钻孔布置位置区域瓦斯积聚程度高,为钻孔抽采瓦斯提供浓度条件;②钻孔布置位置区域裂隙较为发育,为钻孔抽采提供瓦斯源保障;③钻孔布置位置区域岩层受采动影响较小,为钻孔提供稳定性条件。在此基础上,从采动裂隙内瓦斯积聚程度、采动岩层渗透率和采动钻孔稳定性3个方面揭示了水平定向长钻孔布置抽采机理,提出了水平定向长钻孔的位置判据,给出了确定钻孔抽采位置的方法流程,并通过数值模拟、工程实例进行了合理性验证。研究结果表明:依据钻孔位置判据进行钻孔布置抽采的最大瓦斯抽采纯量达2.59 m^(3)/min,为其他对比钻孔的2.56倍;在定向长钻孔抽采作用下,回风巷最大瓦斯体积分数为0.11%~0.72%,风排瓦斯量为0.69~2.79 m^(3)/min,验证了按照钻孔位置确定方法进行钻孔布置抽采的合理性。研究成果可对矿井布置水平定向长钻孔抽采采空区卸压瓦斯提供技术依据,进而提高矿井卸压瓦斯抽采率、促进煤矿绿色开采技术发展。

底水油藏水平井开发水脊规律研究

针对局部底水脊进造成的水平井出水问题,建立了底水油藏水平井开采三维物理模拟系统,研究了底水脊进位置和发展特征,考虑了井筒压降、井眼轨迹和储层非均质性等因素的影响。结果表明,井筒压降使底水在水平井跟端脊进,导致见水时间明显提前,对水脊形成与发展有重要影响;井眼轨迹变化与储层非均质性是底水脊进的敏感因素,与井筒压降共同作用决定了底水脊进位置,存在下凹型井段时,底水易在下凹型井段处脊进;下凹型井段靠近水平井跟端,底水在跟端处脊进,波及范围小;下凹型井段远离跟端促使形成多处水脊,扩大底水波及范围。在非均质性模型中,高渗透区底水易形成水脊,而跟端位于低渗透区时,能促使水脊沿水平方向发展;水脊发展速度影响见水后开发动态,下凹型井段位于跟端会加快水脊发展,见水时间最早,含水率上升速度最快;下凹型井段远离跟端能减缓水脊发展速度;非均质性会加快水脊发展速度,而将跟端布置在低渗透区能在一定程度推迟见水时间,降低含水率上升速度。

BiPAP通气治疗慢性阻塞性肺疾病急性加重伴意识障碍的疗效观察

[目的]探讨无创双水平气道正压（BiPAP）通气治疗慢性阻塞性肺疾病急性加重（AECOPD）呼吸衰竭合并意识障碍患者的疗效。[方法]收集AECOPD呼吸衰竭合并意识障碍患者50例，随机分为治疗组（BiPAP治疗组）及对照组（常规治疗组），每组25例。观察治疗前后患者的生命体征及血气的变化。[结果]治疗24h后治疗组患者pH、PaO2、PaCO2及RR的改善明显好于对照组（P〈0．05）；治疗组及对照组的有效率分别为84％，68％，差异有统计学意义（P〈0．05）。治疗组治疗2～4h后血气指标明显改善（P〈0．05），24h后各项观察指标均显著好转（P〈0．05），至治疗结束时相对稳定。[结论]BiPAP是治疗AECOPD呼吸衰竭合并意识障碍患者的有效手段。初期BiPAP通气治疗应持续24h以上。

新型柔性变极性等离子弧铝合金横焊技术研究

针对中厚板铝合金横向焊接的技术需求和瓶颈问题,开展变极性等离子弧穿孔横焊技术的研究。以8 mm厚铝合金板为研究对象,进行常规变极性等离子弧穿孔横焊试验,发现横焊穿孔熔池很难建立。通过横焊穿孔熔池受力计算、熔化金属流动分析,探究问题产生的原因。推导出熔池背面小孔临界半径与表面张力、电弧力和重力之间的关系式。当受力状态满足关系式时,小孔熔池才能闭合、形成焊缝。依据上述理论,提出柔性变极性等离子弧。该电弧在保证穿孔前提下,通过降低电弧压力,增大小孔临界半径,促进了穿孔熔池的稳定建立。利用该技术实现了8 mm板厚2219铝合金的穿孔横向焊接,接头成形优良。焊前预热和表面氧化膜刮削可大幅度降低横焊接头气孔缺陷。

关于水平层分析法的讨论

基于极限平衡法变分法得出的已有成果的基础上,分析了水平层分析法两个假定的合理性。研究表明,主动土压力强度沿墙高的分布对土条顶底面的法向力作用点位置系数非常敏感;法向力作用点位置系数为墙高的函数,除非在特殊情况下取常数1/2;土条间的切向作用力除非在特殊情况下为0,一般情形下为墙高的函数;水平层分析法使墙顶部的主动土压力强度变大,墙底部附近的主动土压力强度变小,提高了作用点的位置。

水平射孔井射孔参数及起裂压力研究

水平井压裂技术是低渗透油气藏及非常规能源开发的一项重要技术,压裂施工过程中需要射孔作业沟通油气储集区来提高低渗透油气藏的采收率,为此,准确地认识射孔参数对水平井起裂压力的影响是关系到低渗透储层压裂改造的关键环节。基于岩石力学和弹性力学,在现有模型上考虑水平井井筒方位和射孔方位等因素,建立水平射孔井的起裂压力计算模型。计算结果表明,射孔孔眼的起裂点通常在孔壁周向角为0°和180°位置,并且起裂压力受到井筒方位和射孔方位的变化影响较大。

压力传感器定位装置的设计与测试

目的设计一种压力传感器定位装置,提高有创血压测量的准确度,降低交叉感染的风险。方法利用激光定位的方法设计开发压力传感器定位装置,包括支架、激光发射器、固定装置。激光发射器发出的光束对准平卧患者心脏右心房水平十字标记中心点,通过转动激光发射器,使光束指向压力传感器的安装平台,从而固定有创血压测量传感器。验证试验测量定位的准确度和用时、测量压力值得偏差等。结果应用压力传感器定位装置后,压力传感器的定位准确度明显高于目测定位方法,偏差值在0~3 mm,明显小于目测定位(4~8 mm);调整时间明显低于目测定位(7~13 s vs 15~28 s)。使用压力传感器定位装置定位后的压力传感器测量的压力值与目测定位后的压力传感器测量的压力值的数值变化趋势上是基本一致的;偏差值、偏差幅度明显小于目测定位(偏差值:-0.1~0.2 mmHg vs-0.3~0.4 mmHg;偏差幅度:0.3 mmHg vs 0.7 mmHg)。结论有创血压测量的压力传感器定位装置有效提高血压测量的准确度,降低交叉感染的风险,对临床使用具有理论和实践意义。

双水平正压通气在新生儿呼吸窘迫综合征临床治疗中的应用

目的探究新生儿呼吸窘迫综合征(NRDS)采用双水平正压通气(Duo-PAP)治疗方法的临床疗效。方法随机抽取我院64例NRDS患儿,并随机分为观察组和对照组。观察组采用Duo-PAP联合PS(肺表面活性物质)方法治疗。对照组采用鼻塞持续气道正压通气(NCPAP)与PS联合治疗的方法。比较两组患儿的临床指标变化。结果治疗后,两组患儿Pa O2水平与Pa CO2水平(P<0.05,P<0.01)均有所改善,在治疗3 h和12 h后效果尤为显著。在治疗成功率上,虽然观察组比对照组稍高,但差异无统计学意义。结论治疗NRDS采用Duo-PAP方法可提高治疗效率,使呼吸窘迫症状有效改善。

一种纵向地应变观测仪的结构设计

就纵向地应变观测给出一种仪器的设计构想,描述仪器的整体结构、功能及所涉及到的主要配件参数。该仪器的特征是可对某一地区的纵向地应力、横向地应力进行同步观测渴望获得该地区的应力场的变化,从而为地震预报提供出更加可靠的参考信息。

急诊早期应用无创正压通气对重症心衰合并Ⅱ型呼吸衰竭患者缺氧状态和心肺功能的影响

目的:探讨急诊早期应用无创正压通气(NIPPV)对重症心衰合并Ⅱ型呼吸衰竭患者缺氧状态和心肺功能的影响。方法:回顾性分析150例急性重症心衰合并Ⅱ型呼吸衰竭患者,依据治疗过程中通气方式不同分为有创通气组、持续气道正压通气(CPAP)组和双水平气道正压通气(BiPAP)组,每组各50例。比较3组心衰改善情况[心率(HR)、左心室射血分数(LVEF)、每搏输出量(SV)、心输出量(CO)、心脏指数(CI)]及呼吸衰竭改善情况[呼吸频率(RR)、血氧饱和度(SaO_(2))、血气分析(PaO_(2)和PaCO_(2))、通气时间、症状缓解时间、ICU住院时间、气管插管率、死亡率]。结果:治疗后,CPAP组、BiPAP组HR、RR、PaCO_(2)均低于有创通气组(P<0.05),SaO_(2)、PaO_(2)及LVEF、SV、CO、CI均高于有创通气组(P<0.05),且BiPAP组HR、RR、PaCO_(2)均低于CPAP组(P<0.05),SaO_(2)、PaO_(2)均高于CPAP组(P<0.05);CPAP组与BiPAP组LVEF、SV、CO、CI比较差异无统计学意义(P>0.05)。CPAP组、BiPAP组通气时间、症状缓解时间、ICU住院时间均短于有创通气组(P<0.05);CPAP组、BiPAP组气管插管率、死亡率与有创通气组比较,差异无统计学意义(P>0.05)。结论:急诊早期应用BiPAP和CPAP两种正压通气模式治疗重症心衰合并Ⅱ型呼吸衰竭均能发挥显著疗效,迅速纠正缺氧状态,改善心肺功能,且BiPAP较CPAP缓解患者呼吸衰竭效果更明显。