急性呼吸窘迫综合征肺保护性通气策略:循证医学与临床实践的对立和出路

急性呼吸窘迫综合征(ARDS)是急性呼吸衰竭的常见原因,亦是ICU内重症患者,特别是SARS、重症禽流感和重症甲型H_1N_1患者主要的死亡原因.以病理生理改变为基础的肺保护性通气是十多年来ARDS机械通气策略的重大突破,特别是2000年ARDSnet研究获得的小潮气量通气显著降低ARDS病死率的研究结果[1],使得肺保护性通气似乎成为拯救ARDS的"灵丹妙药".     

俯卧位通气对重度急性呼吸窘迫综合征患者血液动力学的影响

<正>急性呼吸窘迫综合征( acute respiratory distress syndrome,ARDS)是因为严重创伤、误吸、严重感染、大手术以及休克等肺内或者肺外严重病变的各种病因所导致的以顽固性低氧血症为主要特征的临床综合征[1～3]。其病理主要是肺泡组织广泛塌陷、通气/血流比值失调和肺内分流增加所致,表现为持续性呼吸窘迫及难治性低氧血症吸氧无法纠正,具有较高的病死率[2,4]。机械通气是目前临床上治疗ARDS的主要手段,当ARDS     

两种肺复张治疗方法用于急性呼吸窘迫综合征的疗效对比

正急性呼吸窘迫综合征(Acute respiratory distress syndrome,ARDS)是各种肺内外致病因素导致肺泡毛细血管炎症感染性损伤,进而导致大量肺泡出现塌陷等病理改变的临床综合征。临床症状主要为肺组织水肿、急性呼吸衰竭及顽固性低氧血症等,患者死亡率可高达50%[1]。机械通气是目前治疗ARDS的主要措施,而肺保护性通气策略是经临床应用验证唯一可明显降低ARDS患者死亡率的通气模式,     

肺保护性通气策略在急性呼吸窘迫综合征中的作用

机械通气是急性呼吸窘迫综合征(ARDS)的重要支持手段,为减少或避免机械通气所致的肺损伤,近年来逐步形成ARDS肺保护-性通气策略。深刻认识ARDS病理生理特点,合理评价肺保护性通气策略,对于提高ARDS患者机械通气效果,改善ARDS预后,具有十分重要的临床意义。     

肺癌术后对侧非对称性急性呼吸窘迫综合征一例报道并文献复习

急性呼吸窘迫综合征(ARDS)起病急,病死率高,以肺容积减少、肺顺应性降低、通气/血流比例严重失调为主要病理生理特征,临床主要表现为进行性低氧血症和呼吸窘迫,肺部影像学主要表现为非均一性渗出性病变。非对称性ARDS在临床上较为少见,易误诊。本文报道了1例肺癌术后对侧非对称性ARDS患者并进行了文献复习,以期提高临床对肺癌术后对侧非对称性ARDS的认识。     

正确认识急性呼吸窘迫综合征患者的自主呼吸

急性呼吸窘迫综合征（acute respiratory distress syndrome,ARDS）是临床常见危重症,病死率较高,肺保护性机械通气仍然是ARDS患者治疗的基石,对于ARDS患者,保留自主呼吸是一把“双刃剑”,ARDS患者在机械通气过程中保持耐受良好的自主呼吸努力可以为患者带来益处,过强的自主呼吸努力则会加重肺损伤。临床医生应该在对患者呼吸驱动有效的评估下,允许患者对自主呼吸努力耐受良好的情况下保留适当自主呼吸努力,使患者从自主呼吸获益,同时避免机械通气相关性肺损伤和患者自身造成的肺损伤。     

肺保护性通气改善急性呼吸窘迫综合征预后的机制

肺保护性通气策略（lung protective ventilation strategy，LPVS）的提出是近年来在急性呼吸窘迫综合征（ARDS）治疗方面的最主要进展，LPVS在临床的应用是ARDS病死率降低的重要原因。最初认为LPVS是通过降低ARDS机械通气过程中的机械性损伤而改善ARDS预后的，但目前研究显示LPVS还可通过降低肺和全身炎症反应、改善肺氧化一抗氧化失衡和细胞凋亡异常等多个机制改善ARDS预后。     

不同水平呼气末正压通气对肺内外源性急性呼吸窘迫综合征患者的影响

应用呼气末正压（PEEP）是急性呼吸窘迫综合征（ARDS）肺保护性通气策略之一,它可以促进氧合,防止呼气末肺泡萎陷,抑制炎性介质释放.而国外研究表明,ARDS患者对同样水平的PEEP反应并不一致,可能与导致ARDS的病因不同有关.我们观察了不同水平PEEP通气对肺内、外源性ARDS患者的影响.     

急性呼吸窘迫综合征的机械通气治疗

急性呼吸窘迫综合征(acute respiratory distress syn-drome,ARDS),多发生于原心肺功能正常的患者,是由于心源性以外的各种肺内、肺外致病因素引起的以肺泡-毛细血管炎症损伤为主的急性Ⅰ型呼吸衰竭,为临床上常见的危重症之一。采用常规吸氧疗法难以纠正患者缺氧症状,即使采用有效的机械通气治疗,病死率仍可达40%~70%[1]。ARDS特征性病理生理改变为弥漫性、非均匀性的肺泡损伤,肺泡腔内大量蛋白质的渗出,肺实变、肺不张及顽固性低氧血症,主要的治疗措施是机械通气,但在机械通气过程中为使ARDS患者动脉血氧分压达到或超过55~60mmHg(1mm…     

两种不同通气方式治疗成人急性呼吸窘迫综合征的疗效比较

肺复张和保护性肺通气策略是近10多年来成人呼吸窘迫综合征(ARDS)机械通气的重大突破,但是目前ARDS的病死率仍高达30%～40%〔1～3〕。高频震荡通气(HFOV)治疗已作为ARDS重要的辅助通气方式〔4〕。本研究对36例常规肺保护性机械通气无效的ARDS患者分别予以手法肺复张结合小潮气量的常频机械通气(CMV)和换用HFOV治疗,比较其疗效。     

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??Abstract??Acute respiratory distress syndrome (ARDS) is a common clinical acute respiratory failure??mechanical ventilation is the primary means of treatment of ARDS.Although mechanical ventilation in the continuing improvement??ARDS mortality remains high.Lung stress and strain is objective response ARDS lung mechanics mechanism indicators.In the future??monitoring of lung stress and strain??stress and strain guidance with lung protective ventilation in ARDS is very important.     

急性呼吸窘迫综合征23例临床分析

目的探讨急性呼吸窘迫综合征（ARDS）的诊断和治疗。方法对23例ARDS患者的临床资料进行回顾性分析。结果23例患者死亡14例（死亡率60．9％）。结论多种危重病都有可能发生ARDS。监测患者的呼吸频率（RR）、经皮血氧饱和度（SpO2）、动脉血气（SaO2、PaO2）和PaO2／FiO2有利于ARDS的早期诊断；ARDS的治疗以机械通气为主，实施保护性肺通气策略，兼顾其他支持性治疗。     

Efficacy of low tidal volume ventilation in patients with different clinical risk factors for acute lung injury and the acute respiratory distress syndrome.

In patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), a recent ARDS Network randomized controlled trial demonstrated that a low tidal volume (VT) mechanical ventilation strategy (6 ml/kg) reduced mortality by 22% compared with traditional mechanical ventilation (12 ml/kg). In this study, we examined the relative efficacy of low VT mechanical ventilation among 902 patients with different clinical risk factors for ALI/ARDS who participated in ARDS Network randomized controlled trials. The clinical risk factor for ALI/ARDS was associated with substantial variation in mortality. The risk of death (before discharge home with unassisted breathing) was highest in patients with sepsis (43%); intermediate in subjects with pneumonia (36%), aspiration (37%), and other risk factors (35%); and lowest in those with trauma (11%) (p < 0.0001). Despite these differences in mortality, there was no evidence that the efficacy of the low VT strategy varied by clinical risk factor (p = 0.76, for interaction between ventilator group and risk factor). There was also no evidence of differential efficacy of low VT ventilation in the other study outcomes: proportion of patients achieving unassisted breathing (p = 0.59), ventilator-free days (p = 0.58), or development of nonpulmonary organ failure (p = 0.44). Controlling for demographic and clinical covariates did not appreciably affect these results. After reclassifying the clinical risk factors as pulmonary versus nonpulmonary predisposing conditions and infection-related versus non-infection-related conditions, there was still no evidence that the efficacy of low VT ventilation differed among clinical risk factor subgroups. In conclusion, we found no evidence that the efficacy of the low VT ventilation strategy differed among clinical risk factor subgroups for ALI/ARDS.     

Inverse ratio ventilation in ARDS. Rationale and implementation

Conventional ventilatory support of patients with the adult respiratory distress syndrome (ARDS) consists of volume-cycled ventilation with applied positive end-expiratory pressure (PEEP). Unfortunately, recent evidence suggests that this strategy, as currently implemented, may perpetuate lung damage by overinflating and injuring distensible alveolar tissues. An alternative strategy--termed inverse ratio ventilation (IRV)--extends the inspiratory time, and, in concept, maintains or improves gas exchange at lower levels of PEEP and peak distending pressures. There are two methods to administer IRV: (1) volume-cycled ventilation with an end-inspiratory pause, or with a slow or decelerating inspiratory flow rate; or (2) pressure-controlled ventilation applied with a long inspiratory time. There are several real or theoretical problems common to both forms of IRV: excessive gas-trapping; adverse hemodynamic effects; and the need for sedation in most patients. Although there are many anecdotal reports of IRV, there are no controlled studies that compare outcome in ARDS patients treated with IRV as opposed to conventional ventilation. Nonetheless, clinicians are using IRV with increasing frequency. In the absence of well-designed clinical trials, we present interim guidelines for a ventilatory strategy in patients with ARDS based on the literature and our own clinical experience.     

Evidencias de la posición en decúbito prono para el tratamiento del síndrome de distrés respiratorio agudo: una puesta al día

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) have high incidence and mortality rates. Most of the recently introduced treatments have failed to improve the prognosis of patients with ALI or ARDS or to reduce mortality. Several studies have shown improved oxygenation in the prone position during mechanical ventilation in patients with ARDS. However, current evidence strongly suggests that placing ARDS patients in prone position does not improve survival or reduce the duration of mechanical ventilation. Therefore, though in clinical practice this position may improve refractory hypoxemia in patients with ARDS, there is no evidence to support its systematic use.     

Akute respiratorische Insuffizienz

Acute respiratory distress syndrome (ARDS) is the clinical manifestation of an acute lung injury caused by a variety of direct and indirect injuries to the lung. The cardinal clinical feature of ARDS, refractory arterial hypoxemia, is the result of protein-rich alveolar edema with impaired surfactant function, due to vascular leakage and dysfunction with consequently impaired matching of ventilation to perfusion. Better understanding of the pathophysiology of ARDS has led to the development of novel therapies, pharmacological strategies, and advances in mechanical ventilation. However, protective ventilation is the only confirmed option in ARDS management improving survival, and few other therapies have translated into improved oxygenation or reduced ventilation time. The development of innovative therapy options, such as extracorporeal membrane oxygenation, have the potential to further improve survival of this devastating disease.     

Tidal volume reduction in patients with acute lung injury when plateau pressures are not high

Use of a volume- and pressure-limited mechanical ventilation strategy improves clinical outcomes of patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS). However, the extent to which tidal volumes and inspiratory airway pressures should be reduced to optimize clinical outcomes is a controversial topic. This article addresses the question, "Is there a safe upper limit to inspiratory plateau pressure in patients with ALI/ARDS?" We reviewed data from animal models with and without preexisting lung injury, studies of normal human respiratory system mechanics, and the results of five clinical trials of lung-protective mechanical ventilation strategies. We also present an original analysis of data from the largest of the five clinical trials. The available data from each of these assessments do not support the commonly held view that inspiratory plateau pressures of 30 to 35 cm H2O are safe. We could not identify a safe upper limit for plateau pressures in patients with ALI/ARDS.     

High-frequency oscillatory ventilation for adult patients with ARDS

High-frequency oscillatory ventilation (HFOV) is characterized by the rapid delivery of small tidal volumes (Vts) of gas and the application of high mean airway pressures (mPaws). These characteristics make HFOV conceptually attractive as an ideal lung-protective ventilatory mode for the management of ARDS, as the high mPaws prevent cyclical derecruitment of the lung and the small Vts limit alveolar overdistension. In this review, we will summarize the literature describing the use of HFOV in adult patients with ARDS. In addition, we will discuss recent experimental studies of HFOV that have advanced our understanding of its mechanical properties. We identified 2 randomized controlled trials (RCTs) and 12 case series evaluating HFOV in adults with ARDS. In these studies, HFOV appears to be safe and consistently improves oxygenation when used as a rescue mode of ventilation in patients with severe ARDS. The two RCTs comparing HFOV to conventional ventilation revealed encouraging results but failed to show a mortality benefit of HFOV over conventional ventilation. Further research is needed to identify optimal patient selection, technique, the actual Vt delivered, and the role of combining HFOV with other interventions, such as recruitment maneuvers, prone positioning, and nitric oxide.