High survival in adult patients with acute respiratory distress syndrome treated by extracorporeal membrane oxygenation, minimal sedation, and pressure supported ventilation

OBJECTIVES: To evaluate the results of treatment of severe acute respiratory distress syndrome (ARDS) with extracorporeal membrane oxygenation (ECMO), minimal sedation, and pressure supported ventilation. DESIGN AND SETTING: Observational study in a tertiary referral center, Intensive Care Unit, Astrid Lindgren Children's Hospital at Karolinska Hospital, Stockholm, Sweden. SUBJECTS AND METHODS: Seventeen adult patients with ARDS were treated with venovenous or venoarterial ECMO after failure of conventional therapy. The Murray score of pulmonary injury averaged 3.5 (3.0-4.0) and the mean PaO2/FIO2 ratio was 46 (31-65). A standard ECMO circuit with nonheparinized surfaces was used. The patients were minimally sedated and received pressure-supported ventilation. High inspiratory pressures were avoided and arterial saturation as low as 70% was accepted on venovenous bypass. RESULTS: In one patient a stable bypass could not be established. Among the remaining 16 patients 13 survived (total survival rate 76%) after 3-52 days (mean 15) on bypass. Major surgical procedures were performed in several patients. The cause of death in the three nonsurvivors was intracranial complications leading to total cerebral infarction. CONCLUSION: A high survival rate can be obtained in adult patients with severe ARDS using ECMO and pressure-supported ventilation with minimal sedation. Surgical complications are amenable to surgical treatment during ECMO. Bleeding problems can generally be controlled but require immediate and aggressive approach. It is difficult or impossible to decide when a lung disease is irreversible, and prolonged ECMO treatment may be successful even in the absence of any detectable lung function.     

Extracorporeal membrane oxygenation for refractory, life-threatening, and herpes simplex virus 1-induced acute respiratory distress syndrome. Our experience and literature review

We report our first experience of treating an immunocompetent adult patient with acute respiratory distress syndrome (ARDS) due to type 1 herpes simplex (HSV1) pneumonitis, using extracorporeal membrane oxygenation (ECMO). Similar cases reported in literature are reviewed as well. The therapeutic options for this particular complication are discussed. Pneumonia caused by HSV1 is a rare finding in immunocompetent individuals; it occurs more often in immunosuppressed and ventilated patients. It is a severe illness; therefore, early diagnosis and initiation of treatment are imperative. Diagnosis is based on cytologic and histologic findings, viral cultures, or serologic methods. This condition can be reversible; however, often, it can progress into refractory ARDS with limited therapeutic options available. We demonstrate the causative role of HSV1 in refractory ARDS of a previously healthy 18-year-old man who presented to the intensive care unit with acute respiratory distress after a week of flulike syndrome. Due to severe hypoxemia and hypercarbia, the patient required mechanical ventilation and later emergent blood oxygenation with extracorporeal support. For the first time in this condition, we used venovenous ECMO management, to rest the lung, sustain blood oxygenation and end-organ oxygen delivery, and promote potential lung recovery. During ECMO and after our etiologic diagnosis, specific therapy was introduced. After viral negativization, corticosteroid therapy (Meduri protocol) was initiated. Extracorporeal membrane oxygenation allowed us to initiate therapy while maintaining end-organ oxygenation and support the patient until lung recovery. After 18 days of ECMO, our patient recovered completely. Near-normal lung structures and functions were documented on a chest x-ray/computed tomography, thoracic ultrasonography, and pulmonary functional tests at hospital discharge and at a 1-year follow-up. Data suggest that severe pulmonary involvement in HVS1 infection associated with septicemia/shock is a rare but often fatal in immunocompetent adult as well. We suggest that ECMO might be the selected treatment for severe refractory ARDS in this clinical scenario. It seems to be an effective and useful ultimate therapeutic strategy for preventing death and furthermore permitting near-full pulmonary function recovery.     

Résultats de l’assistance respiratoire extracorporelle dans les syndromes de détresse respiratoire aiguë sévères

Major technological improvements in extracorporeal membrane oxygenation (ECMO) machines and the positive results of the CESAR trial have reignited the interest for veno-venous (VV)-ECMO in patients with severe acute respiratory distress syndrome (ARDS) and persistent hypoxemia or hypercarbia on conventional mechanical ventilation. The technique has also been successfully used for the most severe ARDS cases associated with the recent Influenza A(H1N1) pandemic. However, since the CESAR study was criticized for methodological limitations and because results of non-randomized case-series of ECMO are prone to selection biases, indications for VV-ECMO use remain highly controversial. Before widespread diffusion of VV-ECMO for severe ARDS, new trials should test the efficacy of early initiation of the technique with tight control of mechanical ventilation in the control group, initiation of ECMO prior to transportation to ECMO centers, and the use of ECMO in every patient randomly assigned to receive it.     

Effectiveness of extracorporeal membrane oxygenation when conventional ventilation fails: Valuable option or vague remedy?

The mortality and morbidity of patients with severe acute respiratory distress syndrome (ARDS) remains high despite the advances in intensive care practice. The low-tidal-volume ventilation strategy (ARDS net protocol) has been shown to be effective in improving survival. Unfortunately, however, some patients have such severe ARDS that they cannot be managed with the ARDS net strategy. In these patients, rescue therapies such as high-frequency ventilation, prone ventilation, nitric oxide, and extracorporeal membrane oxygenation (ECMO) are considered. The CESAR trial has shown that an ECMO-based protocol improved survival without severe disability as compared with conventional ventilation. The recent increased incidence of severe respiratory failure due to H1N1 influenza pandemic has led to an increased use of ECMO. Although several reports showed ECMO use to be encouraging, some scepticism remains. In this article, we reviewed the usefulness of ECMO in patients with severe ARDS in the light of current evidence.     

Extracorporeal membrane oxygenation for severe acute respiratory failure

Extracorporeal membrane oxygenation (ECMO) is a technique for providing life support, in case the natural lungs are failing and are not able to maintain a sufficient oxygenation of the body's organ systems. ECMO technique was an adaptation of conventional cardiopulmonary bypass technique and introduced into treatment of severe acute respiratory distress syndrome (ARDS) in the 1970s. The intial reports of the use of ECMO in ARDS patients were quite enthusiastic, however, in the following years it became clear that ECMO was only of benefit in newborns with acute respiratory failure. In neonates treated with ECMO, survival rates of 80% could be achieved. In adult patients with ARDS, two large randomized controlled trials (RCTs) published in 1979 and 1994 failed to show an advantage of ECMO over convential treatment, survival rates were only 10% and 33%, respectively, in the ECMO groups. Since then, ECMO technology as well as conventional treatment of adult ARDS have undergone further improvements. In conventional treatment lung-protective ventilation strategies were introduced and ECMO was made safer by applying heparin-coated equipment, membranes and tubings. Many ECMO centres now use these advanced ECMO technology and report survival rates in excess of 50% in uncontrolled data collections. The question, however, of whether the improved ECMO can really challenge the advanced conventional treatment of adult ARDS is unanswered and will need evaluation by a future RCT.     

ECMO used successfully in a near fatal case of opioid-induced acute respiratory distress syndrome

Acute Respiratory Distress Syndrome (ARDS) was first recognized during the 1960s. It is a distinct type of hypoxemic respiratory failure characterized by acute abnormality of both lungs. Extracorporeal membrane oxygenation (ECMO) is being increasingly used for patients with severe ARDS refractory to otherwise conventional management. A 29 year old male arrived with Emergency Medical Services (EMS) status post presumed heroin overdose. He was administered Naloxone 2 mg intravenously prior to arrival in the emergency department. The patient arrived in severe respiratory distress with a pulse oximetry level of 50% and was immediately intubated. The patient's pulse oximetry level remained in the seventies despite intubation and aggressive ventilator management. The Intensive Care Unit team in conjunction with cardiothoracic surgery initiated venovenous ECMO therapy in the emergency department itself. The patient was transferred to a tertiary center for venoarterial ECMO that was continued for 6 more days. After an extensive hospitalization, the patient was ultimately transferred to an acute medical rehabilitation center. With the current opioid crisis, emergency physicians and providers need to be aware that opioids can induce severe ARDS refractory to mechanical ventilation. ECMO as a treatment option can be used safely and successfully as described in this unique patient case report.     

Successful management of adult smoke inhalation with extracorporeal membrane oxygenation

Pulmonary complications remain one of the leading causes of mortality in patients with burns. We report two cases of adult patients with thermal and inhalation injuries who were placed on extracorporeal membrane oxygenation (ECMO) and survived. Patient 1 was a 42-year-old male who suffered 15% TBSA and a severe inhalation injury requiring intubation upon arrival to the emergency department. Patient 2 was a 24-year-old female in a house fire who received 20%TBSA and was noted to be in respiratory distress and intubated on the scene by the paramedic team. Three days after admission, patient 1 developed severe respiratory failure. He decompensated, despite maximum conventional management, and was placed on ECMO. After 300 hours of ECMO, his pulmonary function had improved, and he was decannulated. Patient 2 also developed severe refractory respiratory failure and was placed on ECMO. She was decannulated 288 hours later. Both patients were discharged home shortly afterwards and have managed well. ECMO should be considered when patients are facing a respiratory death from inhalation injury on conventional mechanical ventilation.     

Extracorporeal membrane oxygenation for overwhelming Blastomyces dermatitidis pneumonia

Blastomyces dermatitidis is a fungus that is found primarily in endemic areas of the midwestern and southcentral USA. Blastomycosis pneumonia may develop after the inhalation of spores. While blastomycosis may lead to acute or chronic pneumonitis, it will rarely result in the development of the acute respiratory distress syndrome (ARDS). In this situation, mortality rates are 50–80%. Patients who survive, however, commonly show good recovery of pulmonary function. Extracorporeal membrane oxygenation (ECMO), a modified form of cardiopulmonary bypass that allows systemic perfusion, oxygenation, and carbon dioxide removal, may be used to support patients with cardiorespiratory failure that is refractory to conventional therapies. The use of ECMO allows the reduction of high levels of mechanical ventilatory support that may cause iatrogenic injury to the diseased lung. Fungal diseases are often contraindications for ECMO use, since systemic fungal organisms may bind to the ECMO circuit and be difficult to eradicate. It may be reasonable to utilize ECMO, however, if the fungal infection is isolated to the respiratory system. We report the case of a patient with ARDS secondary to blastomycosis pneumonia who was treated with ECMO due to the failure of conventional cardiorespiratory supports. To our knowledge, this is the first report of the use of ECMO for this condition.     

Extracorporeal membrane oxygenation rescue for critically ill children with cardiopulmonary failure北大核心CSCD

Objective To summarize the therapeutic effects of extracorporeal membrane oxygenation (ECMO) on critically ill children with severe cardiopulmonary failure. Methods The pediatric patients supported with ECMO admitted to pediatric intensive care unit (PICU) from December 2015 to August 2017 were enrolled in this study. The data of demographics of patients, diagnosis, indication for ECMO, the procedure of ECMO support, complications, and survival status were analyzed. Results A total of 17 pediatric patients including 9 male and 8 female with severe cardiopulmonary failure treated with ECMO were studied. The median of age was 24 (2, 117) months, and the median of body weight was 12 (5, 33) kg. The indications for initiation of ECMO were cardiovascular failure with poor response to conventional therapy and severe acute respiratory distress syndrome (ARDS) without any beneficial effect obtained from mechanical ventilation. The percutaneous cannulation was done under ultrasound guidance by a team of trained intensivists through right cervical vein and internal carotid artery resulting in veno-Arterial extracorporeal membrane oxygenation support. The mean duration of ECMO support was 212. 5 h with median 188. 5 (3-924) h. All patients were treated with mechanical ventilation for prevention from pulmonary atelectasis. Of 17 patients, 10 were coupled with continuous renal replacement therapy (CRRT) to keep fluid balance. As a result, 11 children (64. 7%) were successfully weaned from ECMO defined as survival for 24 h after ECMO, and 10 children (58. 8%) were alive to discharge from hospital. One of 2 cardiac arrest cases treated with extracorporeal cardiopulmonary resuscitation (ECPR) was alive. During ECMO support, there were 41 adverse events happened including pressure ulcers (64.7%), thrombocytopenia (52. 9%), bleeding (35. 3%) . Conclusions The survival rate at discharge was 58. 8% in pediatric patients with severe cardiopulinonaiy failure with poor response to conventional therapy. Our data suggest that ECMO support is an important rescue technique for pediatric critical illness.     

Necrotizing pneumonia requiring prolonged extracorporeal membrane oxygenation: Pushing the boundaries in pediatric ECMO

Extracorporeal membrane oxygenation (ECMO) is a life‐saving rescue therapy used in acute respiratory failure refractory to invasive mechanical ventilation. Recent studies on positive outcomes of extended ECMO therapy are promising. We describe a case of a 2‐year 8‐month‐old female child with necrotizing pneumonia secondary to Streptococcus pneumoniae, Influenza A, and Mycoplasma pneumoniae, who survived with intact neurological function and no long‐term adverse outcomes after a prolonged ECMO run of 86 days. To the best of our knowledge, this is one of the longer durations of ECMO with transplant‐free survival in a pediatric patient requiring respiratory support with good recovery and a good functional outcome. Allowing time for native lung recovery is pivotal for optimal recovery, despite significant lung injury due to the underlying disease process. With evolving ECMO experience, clinicians may need to re‐consider the conventional maximum duration of ECMO in children with severe respiratory failure on a case‐by‐case basis.     

Pulmonary hypertension in acute respiratory failure

In order to examine the prognostic value of pulmonary arterial hypertension (PAH) in patients with moderate and severe acute respiratory failure (ARF), 225 patients with ARF who had been treated with mechanical ventilation and admitted to our ICU during a 3-yr period (January, 1983 to January, 1986) were prospectively studied. All 70 (31%) patients with moderate and severe ARF also had some form of hemodynamic or pulmonary instability, and were monitored with a pulmonary artery catheter. Of these 70 patients, 38 (54%) had PAH (mean BP 29 +/- 6 mm Hg); their mortality was 79% (30/38). The rest of the patients (n = 32) did not have PAH (mean BP was 15 +/- 3 mm Hg) and their mortality was 44% (14/32) (p less than .01). Thirty patients met all the criteria for adult respiratory distress syndrome (ARDS), and their mortality was 70% (21/30); all of them were included among the 38 PAH patients. ARDS patients who died had a significantly higher pulmonary vascular resistance and a significantly lower cardiac index than patients who survived (p less than .001). We conclude that PAH (present in all our ARDS patients) is a good predictor of mortality in ARF of diverse causes.     

Early veno-venous extracorporeal membrane oxygenation is associated with lower mortality in patients who have severe hypoxemic respiratory failure: A retrospective multicenter cohort study

PurposeThe purpose of the study is to compare outcomes in patients who had severe hypoxemic respiratory failure (Pao₂/fraction of inspired oxygen < 100) who received early veno-venous extracorporeal membrane oxygenation (ECMO) as an adjunct to mechanical ventilation, to those in patients who received conventional mechanical ventilation alone.Materials and methodsThis is a multicenter, retrospective unmatched and matched cohort study of patients admitted between April 2006 and December 2013. Generalized logistic mixed-effects models and Cox proportional hazards models were used to determine the association between treatment with ECMO that was started within 3 days of intensive care unit (ICU) admission and ICU and hospital mortality and length of stay, respectively.ResultsA total of 2440 patients who had severe hypoxemic respiratory failure due to various etiologies were included, 46 who received early veno-venous ECMO and 2394 unmatched and 398 matched controls who received conventional ventilation alone. Compared to matched controls, ECMO was associated with a lower odds of ICU (odds ratio [95% confidence interval], 0.30 [0.13-0.67]) and inhospital death (odds ratio 0.30 [0.14-0.67]). In addition, ECMO was associated with longer times to discharge from ICU and hospital (hazard ratio, 0.42 [0.37-0.47] and 0.53 [0.38-0.73], respectively).ConclusionsIn this observational study, use of early ECMO compared to conventional mechanical ventilation alone in patients who had severe hypoxemic respiratory failure was associated with a lower risk of mortality and a longer length of stay.     

5例应用体外膜肺氧合治疗重症急性呼吸窘迫综合征的护理

总结了5例应用体外膜肺氧合(extracorporeal membrane oxygenation,ECMO)治疗重症急性呼吸窘迫综合征患者的护理经验.5例中4例经ECMO治疗8d后成功撤离,病情好转出院,1例撤离ECMO后并发肺间质纤维化.ECMO治疗过程中加强基础护理,密切监测生命体征及血液生化等基础指标,做好机械通气及气道管理,细化ECMO管理,特别是重视并发症的预防与监护非常重要.     

Non-conventional techniques of ventilatory support

The non-conventional techniques for ventilatory support represent a new approach to the management of patients with respiratory failure. A large number of studies indicate that these techniques can maintain adequate gas exchange under conditions in which the traditional concepts of gas transport no longer hold. We have reviewed the group of techniques, collectively called high frequency ventilation (HFV), in which the tidal volumes are much less (1 to 5 ml per kg) than those observed during conventional mechanical ventilation. Although HFV has theoretical advantages in some clinical settings, it has been shown to be superior to conventional mechanical ventilation in but a few. HFV appears to provide adequate ventilation while still allowing access to tracheal and laryngeal surgical fields. It has been successful during pneumonectomy, and in the treatment of bronchopleural fistulae. The relevance of tracheal insufflation (TRIO) of oxygen and constant flow ventilation (CFV) to the human clinical setting is uncertain. TRIO may be useful to oxygenate patients who are difficult to intubate, or TRIO could be applied for ventilation of patients involved in mass casualties. Although CFV does not maintain normal levels of PaCO2 in humans, it can provide adequate oxygenation. It might be clinically applicable during thoracic surgery, in which movement of the abdominal and thoracic contents associated with conventional mechanical ventilation is undesirable. During CFV, the lung is kept motionless with sufficient airway pressures to maintain patency of airways and alveoli. CFV is useful as a tool for studying phenomena affected by breathing. The rationale for the use of an artificial lung during extracorporeal membrane oxygenation (ECMO) or extracorporeal carbon dioxide removal with low positive pressure ventilation (ECCO2R-LFPPV) in the treatment of acute respiratory failure is to provide temporary respiratory function while the pulmonary lesion is being treated or is resolving. The factors that most limit the usefulness of ECMO are not technical but relate to the ability of the lung to recover structurally and functionally after a severe insult. Poor survival figures in the published series of ECMO in adults reflect the gravity of illness prior to treatment. However, results in neonates have been quite encouraging. ECCO2R allows less exposure of blood to the extracorporeal circuit and avoids the reduction in pulmonary blood flow associated with ECMO. Although the reported survival of adults with severe acute respiratory failure treated with ECCO2R is extremely promising, it is important to point out that none of the published reports are controlled, randomized studies.(ABSTRACT TRUNCATED AT 400 WORDS)     

Extending the limits of extracorporeal membrane oxygenation: lung rest for a child with non-specific interstitial pneumonia

Objective Veno-venous extracorporeal membrane oxygenation (ECMO) is an established therapy for the treatment of respiratory failure. Traditionally ECMO has been used to support patients with an acute, reversible disease process, with a predictable outcome. We report the successful use of veno-venous ECMO for an unusual indication.Patient A 10-year old girl was admitted to intensive care with severe, hypoxic respiratory failure on the background of a 2-month history of worsening respiratory symptoms. She required high levels of conventional positive pressure ventilation, and high frequency oscillation. Lung biopsy confirmed a non-specific interstitial pneumonia, and the patient was commenced on immune suppressive therapy. Her clinical course was further complicated by pulmonary haemorrhage and severe air leak.Interventions On day 20 after admission the patient was placed on veno-venous ECMO for lung rest while awaiting a response to continued medical treatment. She required ECMO for 20 days, during which time sedation was reduced, and she was able to interact with those around her. The patients ventilatory requirements after decannulation were minimal, and she subsequently made a steady clinical recovery.Conclusions ECMO was safely and successfully used to provide a period of lung rest and time for medical therapy to take effect in a child with an unusual indication for support: a rare disease with an uncertain outcome on the background of prolonged mechanical ventilation.     

Detectable serum ethylene glycol levels after subcutaneous injection of antifreeze

Context. Paraquat is a widely used herbicide that can cause severe to fatal poisoning in humans. The irreversible and rapid progression of pulmonary fibrosis associated with respiratory failure is the main cause of death in the later stages of poisoning. There are infrequent reports of successful lung transplants for cases of severe paraquat poisoning. We expect that this successful case will provide a reference for other patients in similar circumstances. Case details. A 24-year-old female was sent to the hospital approximately 2 hours after ingesting 50 ml of paraquat. She experienced rapidly aggravated pulmonary fibrosis and severe respiratory failure. On the 34th day after ingestion, she underwent intubation and invasive mechanical ventilation. The patient was evaluated for lung transplantation, and veno-venous extracorporeal membrane oxygenation (ECMO) was established as a bridge to lung transplantation on the 44th day. On the 56th day, she successfully underwent a bilateral sequential lung transplantation. Through respiratory and physical rehabilitation and nutrition support, the patient was weaned from mechanical ventilation and extubated on the 66th day. On the 80th day, she was discharged. During the 1-year follow-up, the patient was found to be in good condition, and her pulmonary function improved gradually. Conclusion: We suggest that lung transplantation may be an effective treatment in the end stages of paraquat-induced pulmonary fibrosis and consequential respiratory failure. For patients experiencing a rapid progression to a critical condition in whom lung transplantation cannot be performed immediately (e.g., while awaiting a viable donor or toxicant clearance), ECMO should be a viable bridge to lung transplantation.     

Extracorporeal support for trauma: A trauma quality improvement project (TQIP) analysis in patients with acute respiratory distress syndrome

IntroductionThe use of extracorporeal membrane oxygenation (ECMO) in trauma patients with severe acute respiratory distress syndrome (ARDS) continues to evolve. The objective of this study was to perform a comparative analysis of trauma patients with ARDS who received ECMO to a propensity matched cohort of patients who underwent conventional management.MethodsThe Trauma Quality Improvement Program (TQIP) database was queried from 2013 to 2016 for all patients with ARDS and those who received ECMO. Demographics, as well as clinical, injury, intervention, and outcome data were collected and analyzed. Patients with ARDS were divided into two groups, those who received ECMO and those who did not. A propensity score analysis was performed using the following criteria: age, gender, vital signs (HR, SBP) and GCS on admission, Injury Severity Score (ISS), and Abbreviated Injury Scale (AIS) score in several body regions. Outcomes between the groups were subsequently compared using univariate as well as Cox regression analyses.Secondary outcomes such as hospitalization (HLOS), ICU length-of-stay (LOS) and ventilation days stratified for patient demographics, timing of ECMO and anticoagulation status were compared.ResultsOver the 3-year study period, 8990 patients with ARDS were identified from the TQIP registry. Following exclusion, 3680 were included in the final analysis, of which 97 (2.6%) received ECMO. On univariate analysis following matching, patients who underwent ECMO had lower overall hospital mortality (23 vs 50%, p < 0.001) with higher rates of complications (p < 0.005), including longer HLOS. In those undergoing ECMO, early initiation (<7 days) was associated with shorter HLOS, ICU LOS, and fewer ventilator days. No difference was observed between the two groups with regard to anticoagulation.ConclusionExtracorporeal membrane oxygenation use in trauma patients with ARDS may be associated with improved survival, especially for young patients with thoracic injuries, early in the course of ARDS. Anticoagulation while on circuit was not associated with increased risk of hemorrhage or mortality, even in the setting of head injuries. The mortality benefit suggested with ECMO comes at the expense of a potential increase in complication rate and prolonged hospitalization.     

Extracorporeal membrane oxygenation and high-frequency oscillatory ventilation: potential therapeutic relationships

Eighteen neonates 33 to 42 wk gestational age with severe respiratory failure were referred for extracorporeal membrane oxygenation (ECMO). Sixteen ultimately met the ECMO criteria, of whom 15 were first offered high-frequency oscillatory ventilation (HFOV). Seven responded to HFOV alone and did not require ECMO treatment. Eight of the nine remaining patients were placed on ECMO support with HOFV. Infants who responded to HFOV alone tended to have pneumonia more than meconium aspiration, to be smaller and more immature, to have higher Apgar scores, and to have suffered severe hypoxia (alveolar-arterial oxygen pressure difference over 600 torr) for less time than the ECMO group. Although patient numbers are small, a trend is noted which favors HFOV treatment alone in terms of the duration of HFOV, the total duration of assisted ventilation, the rapidity with which extubation was accomplished, and the length of hospital stay.     

Prospective evaluation of combined high-frequency ventilation in post-traumatic patients with adult respiratory distress syndrome refractory to optimized conventional ventilatory management

This study explores the value of combined high-frequency ventilation (CHFV) in a prospective clinical trial of 35 patients suffering from severe post-traumatic and/or septic adult respiratory distress syndrome (ARDS) who were refractory to conventional controlled mechanical ventilatory (CMV) support. The severity of ARDS was quantified by lung mechanics and gas exchange variables and the patients were classified on clinical grounds as well as on the basis of their respiratory index/pulmonary shunt relationship [RI/(Qsp/Qt)]. During the same time period as the CHFV study, data from these patients were compared to those from 88 ARDS patients who had quantitatively similar degrees of respiratory insufficiency, but who were treated only with controlled mechanical ventilation (CMV). The use of CHFV in the 35 CMV refractory patients resulted in an increase in expired tidal volume (VTE) by reducing the CMV inspired tidal volume (VTI) while increasing the volume component derived from high-frequency ventilation (HFV). This procedure appeared to reveal potentially salvageable ARDS patients who were refractory to CMV. In these patients, CHFV significantly reduced pulmonary mean airway pressure (Paw). The RI also decreased significantly and it was possible to reduce significantly the FIO2. In surviving ARDS patients treated with CHFV, an improvement in blood gases at reduced FIO2, without decreased cardiac output, was produced. The CHFV technique was used for less than or equal to 25 days and resulted in 23% survival of patients who were clinically and physiologically indistinguishable from the patients in the ARDS nonsurvivor group who were treated by CMV only. In surviving CHFV patients the decrease in Paw permitted a sustained, or increased, cardiac output with a rise in the oxygen delivery/oxygen consumption ratio, thus allowing for a higher PaO2 for any given level of pulmonary shunt.     

体外膜肺氧合对成人急性呼吸窘迫综合征患者预后影响的Meta分析和系统评价

目的 探讨体外膜肺氧合(ECMO)对急性呼吸窘迫综合征(ARDS)患者预后的影响.方法 计算机检索和手工检索收集1966-2010年ECMO治疗成人ARDS的英文和中文临床研究,按纳入与排除标准选择文献,提取资料,采用RevMan 5.0软件对数据进行Meta分析,对ECMO临床研究进行系统评价.结果 共纳入3篇随机对照研究,随机效应模型显示ECMO不降低成人重症ARDS患者病死率[RR=0.95(95%CI:0.76-1.18),P=0.64],但按发表时间的累积Meta分析显示ECMO呈现保护性效应;与以往临床研究相比,最近一项观察性临床研究显示ECMO明显降低甲型H1N1流感导致的重症ARDS患者病死率.结论 现有研究尚不能证实ECMO能改善成人ARDS患者预后,但对于病因可逆的重症ARDS患者早期应用ECMO可取得较好临床效益.

Abstract：

Objective To investigate the effects of extracorporeal membrane oxygenation (ECMO) on survival of adult from acute respiratory distress syndrome (ARDS). Method We searched Pubmed, Embase, Cochrane Library, Web of Science databases to find relevant literatues on ECMO in treatment of ARDS, which are reported from January 1966 to June 2010. Meta analyses was performed. Results Three papers about randomized controlled trial (RCT) of evaluating ECMO in patients with severe ARDS were enrolled for analyses. Meta-analysis of the three randomized controlled trials revealed ECMO did not decrease the mortality of ARDS patients. However, the cumulative meta-analysis of randomized trials showed ECMO had a protective effect on patients with ARDS. The most recent observational studies suggested that ECMO significantly decreased the mortality of ARDS caused by H1 N1 viral pneumonia. Conclusions There is no evidence to prove the benefit of ECMO in patients with ARDS. However, ECMO should be considered to use in early stage of ARDS as a last rescue resort for potentially reversible severe acute respiratory failure. Further investigation of large sample of high quality RCTs is needed.