Adult Respiratory Failure Research Articles

Extracorporeal heart and lung replacement procedures

ZusammenfassungDie Verwendung eines extrakorporalen Unterstützungsystems stellt bei kardialem und/oder pulmonalem Versagen eine etablierte Therapieoption dar. Auch wenn die wissenschaftliche Evidenz quantitativ noch nicht ausreichend gesichert ist, gibt es zunehmend Hinweise aus einzelnen Studien [z. B. Conventional Ventilation or ECMO for Severe Adult Respiratory Failure (CESAR) Trial], dass die „extracorporeal membrane oxygenation“ (ECMO) als pumpenbetriebenes venovenöses Verfahren beim schweren Lungenversagen eine lebensrettende Maßnahme ist. Initial als „rescue option“ beim kardialen Versagen nach Kardiotomie etabliert, erfährt der „extracorporeal life support“ (ECLS) zunehmende Verbreitung als pumpenbetriebenes venoarterielles Herz-Kreislauf-Unterstützungsystem im kardiogenen Schock bei Myokardinfarkt, als „Bridging“-Maßnahme zur Transplantation und im Rahmen einer erweiterten Reanimation. Der „pumpless extracorporeal lung assist“ (pECLA) als pumpenloses arteriovenöses Verfahren ist technisch einfacher zu handhaben, garantiert jedoch nur eine suffiziente Decarboxylierung ohne ausreichende Oxygenierung. Daher wird dieses Verfahren insbesondere im Rahmen eines primär hyperkapnischen Lungenversagens mit respiratorischer Acidose angewendet, um eine lungenprotektive Beatmung zu ermöglichen. Enorme technische Enwticklungen und v. a. die extreme Miniaturisierung der extrakorporalen Unterstützungsysteme dürfen jedoch nicht darüber hinwegtäuschen, dass es sich um eine invasive Therapie mit einer hohen Inzidenz von schwerwiegenden Komplikationen handelt. Vor diesem Hintergrund müssen die weite Verbreitung dieser Technologie kritisch hinterfragt und vielmehr die Konzentrierung auf Zentren mit hoher Expertise gefordert werden.

Blood oxygenation and decarboxylation determinants during venovenous ECMO for respiratory failure in adults

This study was designed to optimize the latest generation venovenous (vv)-extracorporeal membrane oxygenation (ECMO)-circuit configuration and settings based on the evaluation of blood oxygenation and CO2 removal determinants in patients with severe acute respiratory distress syndrome (ARDS) on ultraprotective mechanical ventilation. Blood gases and hemodynamic parameters were evaluated after changing one of three ECMO settings, namely, circuit blood flow, FiO(2ECMO) (fraction of inspired oxygen in circuit), or sweep gas flow ventilating the membrane, while leaving the other two parameters at their maximum setting. Ten mechanically ventilated ARDS patients (mean age 44 ± 16 years; 6 males; mean hemoglobin 8.0 ± 1.8 g/dL) on ECMO for a mean of 9.0 ± 3.8 days) receiving femoro-jugular vv-ECMO were evaluated. vv-ECMO blood flow and FiO(2ECMO) determined arterial oxygenation. Decreasing the ECMO flow from its baseline maximum value (5.8 ± 0.8 L/min) to 40% less (2.4 ± 0.3 L/min) significantly decreased mean PaO2 (arterial oxygen tension; 88 ± 24 to 45 ± 9 mm Hg; p < 0.001) and SaO2 (oxygen saturation; 97 ± 2 to 82 ± 10%; p < 0.001). When the ECMO flow/cardiac output was >60%, SaO2 was always >90%. Alternatively, the rate of sweep gas flow through the membrane lung determined blood decarboxylation, while PaCO2 (arterial carbon dioxide tension) was unaffected when the ECMO blood flow and FiO(2ECMO) were reduced to <2.5 L/min and 40%, respectively. In three additional patients evaluated before and after red blood cell transfusion, O2 delivery increased after transfusion, allowing lower ECMO flows to reach adequate SaO2. For severe ARDS patients receiving femoro-jugular vv-ECMO, blood flow was the main determinant of arterial oxygenation, while CO2 elimination depended on sweep gas flow through the oxygenator. An ECMO flow/cardiac output >60% was constantly associated with adequate blood oxygenation and oxygen transport and delivery.

The experience of extracorporeal membrane oxygenation for severe acute respiratory failure in adults

To summarize the experience of extracorporeal membrane oxygenation (ECMO) for patients with severe acute respiratory failure in adults and to investigate the factors associated with death. The clinical data of patients with severe acute respiratory failure supported with ECMO in respiratory intensive care unit of Beijing Chaoyang Hospital from November 2009 to December 2011 were prospectively collected and analyzed. The data included general condition before EMCO, blood gas analysis, hemodynamics, ventilator settings of mechanical ventilation and complications during ECMO. The primary outcome was death or severe disability within 3 months. Statistical software of SPSS (version 16.0) was used for data analysis. Twenty-five patients with severe respiratory failure received ECMO treatment, of which 16 patients were analyzed. The mean age was (45 ± 14) years old (range, 22 - 64 years old). Thirteen patients were male. Before ECMO, all of the patients were treated with invasive positive pressure ventilation for (72 ± 64) hours. Eight patients had been treated with noninvasive ventilation for a median of 55(10-114) hours. Patients had severe respiratory failure despite advanced mechanical ventilator support. The mean PaO2/fraction of inspired oxygenation (FiO2) ratio was (54 ± 18) mm Hg (1 mm Hg = 0.133 kPa), positive end-expiratory pressure (PEEP) was (11 ± 6) cm H2O(1 cm H2O = 0.098 kPa), Murray lung injury score was 3.6 ± 0.5, serum lactate was (2.5 ± 2.0) mmol/L, serum white blood cell count was (16 ± 6)×10(9)/L, and APACHEII score was 17 ± 8. All of the patients were treated with venous-venous ECMO (VV-ECMO). The change of mechanical ventilation settings were (pre-ECMO vs 2 hours post-ECMO): FiO2 1.0 vs 0.55 ± 0.21, PEEP (11 ± 6) vs (9 ± 6) cm H2O, V(T) (6.8 ± 2.2) vs (4.4 ± 2.0) ml/kg PBW, peak airway pressure (27 ± 8) vs (24 ± 7) cm H2O, respiratory rate (37 ± 10) vs (23 ± 10) breaths/min. Arterial blood gas, including pH, PaO2 and PaCO2 were significantly improved after ECMO running 24 and 48 hours (P < 0.05). The mean VV-ECMO support interval was (9.7 ± 9.6) days (range, 2 - 41 days). Ten patients were successfully weaned from ECMO, of whom 2 died in ICU. Three patients died during ECMO, while another 3 patients died after withdrawal of further treatment. Eight patients survived to 3 months without severe disability. In a multi-variate Cox regression model, pre-ECMO factors including lower PaO2/FiO2 and increasing white blood cell count were associated with increased risks of death (RR was 0.733, 1.701 respectively, both P values < 0.05). VV-ECMO is a potentially effective approach for severe acute respiratory failure. PaO2/FiO2 and white blood cell count pre-ECMO may be the risk factors for poor outcome.

What is the niche for extracorporeal membrane oxygenation in severe acute respiratory distress syndrome?

This article reviews the results of case series and trials which evaluated venovenous extracorporeal membrane oxygenation (VV-ECMO) for severe respiratory failure. Potential indications of the technique in this setting are discussed. Major technological improvements in extracorporeal membrane oxygenation (ECMO) machines and the positive results of the conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR) trial have reignited interest in 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 as a rescue therapy for the most severe ARDS cases associated with the recent Influenza A(H1N1) pandemic. However, as the CESAR study was criticized for methodological limitations and because results of nonrandomized case-series of ECMO are prone to selection biases, indications for VV-ECMO 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.

Critical care in the ED: potentially fatal asthma and acute lung injury syndrome.

Emergency department clinicians are frequently called upon to assess, diagnose, and stabilize patients who present with acute respiratory failure. This review describes a rapid initial approach to acute respiratory failure in adults, illustrated by two common examples: (1) an airway disease – acute potentially fatal asthma, and (2) a pulmonary parenchymal disease – acute lung injury/acute respiratory distress syndrome. As such patients are usually admitted to hospital, discussion will be focused on those initial management aspects most relevant to the emergency department clinician.

Technological advances in extracorporeal membrane oxygenation for respiratory failure

Extracorporeal membrane oxygenation (ECMO) for neonatal and pediatric cardiac and/or respiratory failure is well established, and its use for adult respiratory failure is rapidly increasing. Management strategies developed over the past 30 years coupled with significant recent technological advances have led to improved ECMO survival. These new technologies are expanding the potential applications for ECMO in exciting ways, including new patient populations and the ability to make ECMO mobile for both intra- and inter-hospital transport. In this article, we highlight some of the recent technological advances and their impact on the utilization of ECMO in increasingly diverse patient populations.

Subclavian Insertion of the Bicaval Dual Lumen Cannula for Venovenous Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) has demonstrated utility in the management of adult respiratory failure refractory to mechanical ventilation. The recent introduction of a bicaval dual-lumen ECMO cannula has improved the efficiency of venovenous ECMO and has enabled the concept of full extracorporeal respiratory support in place of mechanical ventilation. Standard placement of this cannula through the right internal jugular vein is particularly troublesome in individuals of short stature, because of excess cannula length. We describe a method for cannula placement through the left subclavian vein that is well suited for smaller patients and convenient for patient mobility.

The need for an organized ECMO-based respiratory program in Japan

Extracorporeal membrane oxygenation (ECMO) is an expanded clinical application of cardiopulmonary bypass originally introduced in the mid 1950s, which allowed a longer period of support than the standard bubble and film type oxygenator and rapidly gained acceptance in cardiothoracic surgery. It was, therefore, logical to use ECMO temporarily in patients presenting with acute life-threatening hypoxemia. In a review published in 1973, Lefrak et al. [1] reported a 15 % survival rate in 41 patients with refractory hypoxemia treated with membrane oxygenation. An identical survival rate was found by Gille and Bagniewski [2], in 233 patients with acute respiratory distress syndrome (ARDS) treated with ECMO between 1966 and 1975. However, in the randomized study by Zapol et al. [3], in patients presenting with respiratory distress, the survival among 42 patients assigned to ECMO was only 9.5 %, compared with 8.3 % in 48 patients assigned to standard mechanical ventilation. In a study published in 1994, of 40 patients suffering from severe ARDS, Morris et al. [4] reported a 33 % survival rate among the 21 patients randomly assigned to veno-venous ECMO for the extracorporeal removal of CO2, versus 42 % among the 19 patients assigned to mechanical ventilation. In 1996, a large randomized trial in the United Kingdom found ECMO effective in neonates presenting with severe, though potentially reversible, respiratory failure. Thereafter, the enthusiasm for using ECMO for respiratory distress seemed to wane, except for its use in neonates or for lung transplantation. By 2008, over 21,500 neonates had been treated with ECMO worldwide, of whom 76 % survived to hospital discharge [5]. Meanwhile, among the few medical centers that continued to use ECMO for severe ARDS, 2 institutions, in the United States and Sweden, reported survival rates of 54 % in 100 patients and 76 % in 16 patients, respectively [6, 7]. The Extracorporeal Life Support Organization reported retrospective, uncontrolled data collected from 1986 to 2006 in 1,473 adults with severe respiratory failure treated with ECMO, whose median age was 34 years, and of whom 50 % survived to discharge from the hospital [8]. In that analysis, veno-venous bypass was associated with a higher survival than veno-arterial bypass. The conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR) trial, conducted in the United Kingdom between 2001 and 2006, showed that the transfer of adults with severe but potentially reversible respiratory failure, whose Murray score exceeded 3.0 or who had a pH of \7.20 on optimal conventional therapy, to a center with an ECMO-based management protocol, improved the survival significantly without severe residual disability [9]. In the ECMO-assigned group 57 of 90 patients (63 %) survived, compared with 41 of 87 (47 %) in the conventional management group. Of the 90 patients assigned to the ECMO group, 68 did undergo ECMO, while 19 of the 22 remaining patients were transferred to an ECMO center and were managed by lung protective measures. While it was argued that the exclusion of the 22 patients who did not undergo ECMO would have canceled its positive effect, this study did show that transfer of patients to an ECMO center improved the clinical outcome. This comment refers to the article available at doi:10.1007/s00540-012-1402-x.

Venovenous Extracorporeal Membrane Oxygenation in Adults: Practical Aspects of Circuits, Cannulae, and Procedures

INTEREST IN extracorporeal membrane oxygenation (ECMO) for treating severe respiratory failure in adults has increased substantially in the last 5 years. There are several reasons for this increase. The first reason is the publication of the CESAR study in 2009, which showed improved survival in adults with severe acute respiratory distress syndrome (ARDS) randomized to consideration of ECMO compared with patients treated conventionally.1 Second is the H1N1 influenza pandemic of 2009 and 2010, which resulted in a substantial increase in the use of ECMO for treating severe respiratory failure.

Trends in and perspectives on extracorporeal membrane oxygenation for severe adult respiratory failure

Various approaches such as ventilator management involving lung-protective ventilation, corticosteroids, prone positioning, and nitric oxide have failed to maintain sufficient lung oxygenation or appropriate ventilation competence in very severe acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) has been aggressively introduced for such patients, although in only a few institutions. The clinical usefulness of ECMO in a large-scale multicenter study (CESAR trial, 2009) and continued development/improvement of ECMO devices have facilitated performance of ECMO, with further increase in the number of institutions adopting ECMO therapy. Clinical usefulness of ECMO was documented in many cases of severe ARDS secondary to influenza A (H1N1) 2009 infection. ECMO requires establishment of an appropriate management system to minimize fatal complications (e.g., hemorrhage), which requires a multidisciplinary team. This, in combination with a new technique, interventional lung assist, will further extend the indications for ECMO. ECMO can be expected to gain importance as a respiratory support technique.

Good response on high nasal oxygen flow reduces the need for intubation in adult respiratory failure

High nasal flow (HNF) therapy has proven its efficiency in acute respiratory failure when compared to conservative oxygen therapy [1]. This study was performed to find a responding and nonresponding group on HNF therapy in adults with hypoxic respiratory insufficiency measured by oxygenation and work of breathing.

The role of high-frequency oscillatory ventilation in the treatment of acute respiratory failure in adults

High-frequency oscillatory ventilation (HFOV) is increasingly used in adults with the acute respiratory distress syndrome (ARDS), who remain hypoxemic during conventional mechanical ventilation. In this review, we will summarize the trials evaluating HFOV in adults with ARDS and discuss issues relevant to the clinician regarding the use of HFOV. Several observational and randomized trials support the safety of HFOV and improvements in oxygenation in adult patients with severe ARDS, who remain hypoxemic during conventional mechanical ventilation. HFOV theoretically meets the goals of lung-protective ventilation. On the basis of the current evidence, HFOV is associated with improvements in oxygenation in severe, adult ARDS. However, whether HFOV influences mortality, length of ICU stay, ventilator-free days, quality-of-life factors and is cost-effective remains to be determined. Large, prospective, randomized controlled trials such as the ongoing OSCAR and OSCILLATE trials will help further define the role of HFOV in adult ARDS.

Extracorporeal membrane oxygenation for respiratory failure in adults

This article reviews case series and trials that evaluated extracorporeal membrane oxygenation (ECMO) for respiratory failure and describes patient and circuit management in the modern era of ECMO support. In recent years, pivotal progress has been made in the conception and construction of ECMO circuits. They are now simpler, safer, require less anticoagulation and are associated with fewer bleeding complications. The encouraging results of the efficacy and economic assessment of conventional ventilatory support versus ECMO for severe adult respiratory failure (CESAR) trial performed in the United Kingdom and good outcomes of patients who received ECMO as rescue therapy during the recent H1N1 influenza pandemic, in which the latest generation of ECMO technology was used, reignited interest in ECMO for severe acute respiratory distress syndrome (ARDS). The latest generation of ECMO systems is more biocompatible, better performing and longer lasting. Although recent studies suggested that veno-venous ECMO might improve the outcomes of patients with ARDS, indications for ECMO use remain uncertain. Future trials of ECMO for severe ARDS should strictly control for standard-of-care mechanical ventilation strategies in the control group and early transportation on ECMO for patients in the intervention arm.

First experience with the new portable miniaturized extracorporeal membrane oxygenation system Cardiohelp for severe respiratory failure in adults

Aims: Over the last decade, technical improvements in extracorporeal membrane oxygenation (ECMO) equipment have reduced procedure-related complications, and have made ECMO an effective option for patients with acute respiratory distress syndrome (ARDS) if conventional therapy fails.

Advantages and limitations of the novel single site vs. the standard two site access for veno-venous extracorporeal membrane oxygenation (vvECMO) in adults. The Regensburg experience

Objective: A comparison of the new single site vs. the standard two site access for vvECMO in adult respiratory failure.

First experience with the new portable extracorporeal membrane oxygenation system Cardiohelp for severe respiratory failure in adults

Over the last decade, technical improvements in extracorporeal membrane oxygenation (ECMO) equipment have reduced procedure-related complications and have made ECMO an effective option for patients with acute respiratory distress syndrome (ARDS) if conventional therapy fails. In this report, we present our early experience with the Cardiohelp, a new portable miniaturized ECMO system, in 22 consecutive patients with ARDS. All patients were placed on venovenous ECMO. Cannulas were inserted percutaneously, employing the Seldinger technique. Data were collected prospectively. The median patient age was 47 years (36 to 61). Fifteen patients from regional hospitals were too unstable for conventional transport and were placed on Cardiohelp at the referring hospital and then transported to our institution. The patients were transported by ambulance (n=2) or helicopter (n=13) over a distance of 50-250 km. Cardiohelp support resulted in immediate improvement of gas exchange and highly protective ventilation. The median duration of support was 13 days (8 to 19). An exchange of the device was necessary in 9 patients. Sixteen patients (72.7%) were successfully weaned from ECMO and fifteen patients (68.2%) survived. Device-related complications were not observed. The compact portable ECMO device Cardiohelp is a highly effective method to secure vital gas exchange and to reduce further ventilator-induced lung injury in patients with acute respiratory failure. Crucial technical innovations and ease of device transport and implantation allow location-independent stabilization with consecutive inter-hospital transfer.

The Treatment of Adult Respiratory Distress Syndrome (ARDS) Using Extracorporeal Membrane Oxygenation (ECMO)

Extracorporeal Membrane Oxygenation (ECMO) support to tissue oxygenation has been shown to improve survival in patients with life threatening respiratory distress syndrome or cardiac failure. Extracorporeal life support such as ECMO, including extracorporeal CO2 removal (ECCO2R), is used as temporary support until successful recovery of organs. A recently published multicentre randomized controlled trial, known as the CESAR (conventional ventilation or extracorporeal membrane oxygenation for severe adult respiratory failure) trial, was the first trial to demonstrate the utility of ECMO in acute respiratory distress syndrome (ARDS). During the 2009 influenza A (H1N1) pandemic, there were many reports of patients with severe ARDS related to H1N1 infection treated with ECMO. These reports revealed a high survival rate and effectiveness of ECMO. In this review, we explain the indication of ECMO clinical application, the practical types of ECMO, and complications associated with ECMO. In addition, we explain recent new ECMO technology and management of patients during ECMO support.

Contemporary extracorporeal membrane oxygenation for adult respiratory failure: life support in the new era

Extracorporeal membrane oxygenation (ECMO) has been used in clinical medicine for 40years but remains controversial therapy, particularly in adult patients with severe respiratory failure. Over the last few years, there have been considerable advances in extracorporeal technology and clinical practice, ushering in a new era of ECMO. Many institutions adopted ECMO as rescue therapy during the recent H1N1 influenza pandemic, reigniting the controversy. Hollow-fibre oxygenators and Mendler-designed centrifugal pumps have replaced the old silicon oxygenators and roller pumps. The advantages of these novel systems and the principles that underlie their function are outlined. Advances in cannula technology allow greater ease of patient positioning, in some cases facilitating extubation and ambulation on ECMO. Improvements in ECMO circuitry have led to a reduction in heparin and blood product requirements, with consequently fewer complications. Greater understanding of severe acute respiratory distress syndrome has allowed clinicians to successfully support adults on ECMO for months at a time, as a bridge to either recovery or transplantation. ECMO is safer, cheaper, and simpler than in previous eras. Both circuit and patient can be cared for by a single trained nurse. Additional prospective studies of ECMO for adult respiratory failure are underway. Contemporary ECMO in awake, potentially ambulant patients to provide short-term support for those with acute, reversible respiratory failure and as a bridge to transplantation in those with irreversible respiratory failure is now ready for widespread evaluation.

Critical evaluation of emergency stockpile ventilators in an in vitro model of pediatric lung injury

Modern health care systems may be inadequately prepared for mass casualty respiratory failure requiring mechanical ventilation. Current health policy has focused on the "stockpiling" of emergency ventilators, though little is known about the performance of these ventilators under conditions of respiratory failure in adults and children. In this study, we seek to compare emergency ventilator performance characteristics using a test lung simulating pediatric lung injury. Evaluation of ventilator performance using a test lung. Laboratory. None. Six transport/emergency ventilators capable of adult/child application were chosen on the basis of manufacturer specifications, Autovent 3000, Eagle Univent 754, EPV 100, LP-10, LTV 1200, and Parapac 200D. Manufacturer specifications for each ventilator were reviewed and compared with known standards for alarms and functionality for surge capacity ventilators. The delivered tidal volume, gas flow characteristics, and airway pressure waveforms were evaluated in vitro using a mechanical test lung to model pediatric lung injury and integrated software. Test lung and flow meter recordings were analyzed over a range of ventilator settings. Of the six ventilators assessed, only two had the minimum recommended alarm capability. Four of the six ventilators tested were capable of being set to deliver a tidal volume of less than 200 mL. The delivered tidal volume for all ventilators was within 8% of the nominal setting at a positive end expiratory pressure of zero but was reduced significantly with the addition of positive end expiratory pressure (range, ±10% to 30%; p < .01). All ventilators tested performed comparably at higher set tidal volumes; however, only three of the ventilators tested delivered a tidal volume across the range of ventilator settings that was comparable to that of a standard intensive care unit ventilator. Multiple ventilators are available for the provision of ventilation to children with respiratory failure in a mass casualty scenario. Few of these ventilators possess the minimum alarm functionality and consistently deliver the prescribed tidal volume that allows for safe and effective ventilation of critically ill pediatric patients. These findings will help clinicians understand the performance and limitations of available ventilators intended for use in children.

Extracorporeal membrane oxygenation for severe acute respiratory failure in adults: NICE guidance

Extracorporeal membrane oxygenation (ECMO) is a modified form of cardiopulmonary bypass that allows short-term support for potentially reversible severe acute respiratory and/or cardiac failure in critically ill adults and children....