Extracorporeal life support for patients with acute respiratory distress syndrome: report of a Consensus Conference

Treatment Failure and Clinical Stability in Severe Community-Acquired Pneumonia

Treatment failure and clinical stability are important outcomes in community-acquired pneumonia (CAP). It is essential to know the causes and risk factors for treatment failure and delay in reaching clinical stability in CAP. The study of both as well as the associated underlying mechanisms and host response are key to improving outcomes in pneumonia.

High versus low positive end-expiratory pressure setting in patients receiving veno-venous extracorporeal membrane oxygenation support for severe acute respiratory distress syndrome: study protocol for the multicentre, randomised ExPress SAVER Trial

INTRODUCTION

While limiting the tidal volume to 6 mL/kg during veno-venous extracorporeal membrane oxygenation (V-V ECMO) to ameliorate lung injury in patients with acute respiratory distress syndrome (ARDS) is widely accepted, the best setting for positive end-expiratory pressure (PEEP) is still controversial. This study is being conducted to investigate whether a higher PEEP setting (15 cmH2O) during V-V ECMO can decrease the duration of ECMO support needed in patients with severe ARDS, as compared with a lower PEEP setting.

METHODS AND ANALYSIS

The study is an investigator-initiated, multicentre, open-label, two-arm, randomised controlled trial conducted with the participation of 20 intensive care units (ICUs) at academic as well as non-academic hospitals in Japan. The subjects of the study are patients with severe ARDS who require V-V ECMO support. Eligible patients will be randomised equally to the high PEEP group or low PEEP group. Recruitment to the study will continue until a total of 210 patients with ARDS requiring V-V ECMO support have been randomised. In the high PEEP group, PEEP will be set at 15 cmH2O from the start of V-V ECMO until the trials for liberation from V-V ECMO (or until day 28 after the allocation), while in the low PEEP group, the PEEP will be set at 5 cmH2O. Other treatments will be the same in the two groups. The primary endpoint of the study is the number of ECMO-free days until day 28, defined as the length of time (in days) from successful libration from V-V ECMO to day 28. The secondary endpoints are mortality on day 28, in-hospital mortality on day 60, ventilator-free days during the first 60 days and length of ICU stay.

ETHICS AND DISSEMINATION

Ethics approval for the trial at all the participating hospitals was obtained on 27 September 2022, by central ethics approval (IRB at Hiroshima University Hospital, C2022-0006). The results of this study will be presented at domestic and international medical congresses, and also published in scientific journals.

TRIAL REGISTRATION NUMBER

The Japan Registry of Clinical Trials jRCT1062220062. Registered on 28 September 2022.

PROTOCOL VERSION

28 March 2023, version 4.0.

Treatment of acute respiratory failure: extracorporeal membrane oxygenation

Background: Extracorporeal membrane oxygenation (ECMO) support for tissue oxygenation can improve the survival of patients with life-threatening respiratory distress syndrome or cardiac failure.Current Concepts: Recently, the use of ECMO in acute respiratory distress syndrome has first been reported by a multicenter randomized controlled trial, known as the conventional ventilation or ECMO for severe adult respiratory failure trial. The ECMO application is dramatically increasing with the increasing number of patients experiencing acute respiratory failure due to coronavirus disease 2019 pneumonia. In this review, we explain the indications of the ECMO application and ECMO-associated complications.Discussion and Conclusion: The ECMO application in lung diseases, such as coronavirus disease 2019 and acute respiratory distress syndrome, has significant outcomes in securing the treatment periods and reducing mortality. Therefore, accumulating knowledge and experience in the ECMO application can produce positive outcomes.

"Awake" Extracorporeal Membrane Oxygenation Combined With Continuous Renal Replacement Therapy For the Treatment of Severe Chemical Gas Inhalation Lung Injury

Lung injury caused by chemical gas inhalation is a common clinically severe disease that very easily progresses to acute respiratory distress syndrome (ARDS). Traditional respiratory support consists mainly of mechanical ventilation, but the prognosis of this condition is still poor. "Awake" extracorporeal membrane oxygenation (ECMO) maintains oxygenation, improves ventilation, adequately allows the injured lungs to rest, and avoids complications associated with sedation, intubation, and mechanical ventilation. Continuous renal replacement therapy (CRRT) can provide better fluid management and reduce pulmonary edema. Herein, we describe the case of a patient with severe chemical gas inhalation lung injury who failed to respond to traditional mechanical ventilation and was subsequently treated with awake ECMO combined with CRRT.

SEDAR/SECCE ECMO management consensus document

ECMO is an extracorporeal cardiorespiratory support system whose use has been increased in the last decade. Respiratory failure, postcardiotomy shock, and lung or heart primary graft failure may require the use of cardiorespiratory mechanical assistance. In this scenario perioperative medical and surgical management is crucial. Despite the evolution of technology in the area of extracorporeal support, morbidity and mortality of these patients continues to be high, and therefore the indication as well as the ECMO removal should be established within a multidisciplinary team with expertise in the area. This consensus document aims to unify medical knowledge and provides recommendations based on both the recent bibliography and the main national ECMO implantation centres experience with the goal of improving comprehensive patient care.

A systematic approach to weaning from extracorporeal membrane oxygenation in patients with refractory cardiac failure

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is commonly used to provide haemodynamic support for patients with severe cardiac failure. However, timing ECMO weaning remains challenging. We aimed to examine if an integrative weaning approach based on predefined haemodynamic, respiratory and echocardiographic criteria is associated with successful weaning.

METHODS

All patients weaned from ECMO between April 2017 and April 2019 at Aarhus University Hospital, Denmark, were consecutively enrolled. Predefined haemodynamic, respiratory and echocardiographic criteria were assessed before and during ECMO flow reduction. A weaning attempt was commenced in haemodynamic stable patients and patients remaining stable at minimal flow were weaned from ECMO. Comparisons were made between patients who met the criteria for weaning at first attempt and patients who did not meet these criteria. Patients completing a full weaning attempt with no further need for mechanical support within 24 h were defined as successfully weaned.

RESULTS

A total of 38 patients were included in the study, of whom 26 (68%) patients met the criteria for weaning. Among these patients, 25 (96%) could be successfully weaned. Successfully weaned patients were younger and had less need for inotropic support and ECMO duration was shorter. Fulfilling the weaning criteria was associated with successful weaning and both favourable 30-d survival and survival to discharge.

CONCLUSION

An integrative weaning approach based on haemodynamic, respiratory and echocardiographic criteria may strengthen the clinical decision process in predicting successful weaning in patients receiving ECMO for refractory cardiac failure.

Consenso ECMO colombiano para paciente con falla respiratoria grave asociada a COVID-19

Antecedentes y objetivos

La epidemia de COVID-19 ha creado un desafío sin precedentes en el sistema de salud, generando una demanda creciente. Alrededor del 5% de los pacientes diagnosticados con esta infección requieren ingreso a cuidados intensivos principalmente para soporte ventilatorio con ventilación mecánica por un síndrome de dificultad respiratoria aguda (SDRA) de moderado a grave. Las mortalidades reportadas pueden ser muy altas. Las dos principales causas de muerte en esta infección son la hipoxemia refractaria asociada al SDRA y el shock con insuficiencia orgánica múltiple. La oxigenación con membrana extracorpórea (ECMO) se ha utilizado en pacientes con hipoxemia refractaria sin respuesta a manejo con ventilación mecánica protectora, ventilación en posición prono y relajación muscular. La Organización Mundial de la Salud recomienda considerar ECMO en pacientes adultos y pediátricos con COVID-19 y SDRA refractario, si hay un equipo de expertos disponible.

Métodos

Se utilizó la metodología de consenso formal para generar el Consenso ECMO en la infección SARS-CoV-2 con la mejor evidencia disponible. El desarrollo del consenso combina las técnicas de selección, síntesis, evaluación y gradación de la evidencia: formulación de la pregunta PICO [P - Paciente, Problema o Población. I - Intervención. C - Comparación, control. O - Outcome(s) (muerte)], estrategias de búsqueda sistemática y técnicas de síntesis (metaanálisis).

La evaluación de la calidad de la evidencia y la graduación de la fuerza de las recomendaciones se realizó con la estrategia GRADE, generando al final recomendaciones para los tópicos más relevantes del manejo del paciente con COVID-19 candidato a ECMO y por técnica de consenso formal (Delphi).

Resultados

El consenso colombiano para pacientes con falla respiratoria grave asociada a COVID-19 proporciona un resumen de la evidencia sobre el uso de ECMO en insuficiencia respiratoria hipoxémica aguda grave asociada con la infección SARS-CoV-2, dando recomendaciones sobre sus indicaciones, contraindicaciones, consideraciones y la implementación del grupo ECMOred Colombia.

Conclusiones

El consenso colombiano de ECMO es un documento de guía y consulta para el manejo de pacientes con insuficiencia respiratoria aguda grave refractaria y disfunción cardiovascular asociada con COVID-19 candidatos para ECMO.

The Impact of a Standardized Refractory Hypoxemia Protocol on Outcome of Subjects Receiving Venovenous Extracorporeal Membrane Oxygenation

BACKGROUND

Current mechanical ventilation practice and the use of treatment adjuncts in patients requiring extracorporeal membrane oxygenation (ECMO) for refractory hypoxemia (RH) vary widely and their impact on outcomes remains unclear. In 2015, we implemented a standardized approach to protocolized ventilator settings and guide the escalation of adjunct therapies in patients with RH. This study aimed to investigate ICU mortality, its associated risk factors, and mechanical ventilation practice before and after the implementation of a standardized RH guideline in patients requiring venovenous ECMO (VV-ECMO).

METHODS

This was a single-center, retrospective cohort study of patients undergoing VV-ECMO due to RH respiratory failure between January 2008 and March 2015 (before RH protocol implementation) and between April 2015 and October 2019 (after RH protocol implementation).

RESULTS

A total of 103 subjects receiving VV-ECMO for RH were analyzed. After implementation of the RH protocol, more subjects received prone positioning (6.7% vs 23.3%, P = .02), and fewer received high-frequency oscillatory ventilation than before launching the RH protocol (0% vs 13.3%, P = .01). Plateau pressure was also lower before initiation of ECMO (P = .04) and at day 1 during ECMO (P = .045). Driving pressure was consistently lower at days 1, 2, and 3 after ECMO initiation: median 13.0 (interquartile range [IQR] 10.6-18.0) vs 16.0 (IQR 14.0-20.0) cm H₂O at day 1 (P = .003); 13.0 (IQR 11.0-15.9) vs 15.5 (IQR 12.0-20.0) cm H₂O at day 2 (P = .03); and 12.0 (IQR 10.0-14.5) vs 15.0 (IQR 12.0-19.0) cm H₂O at day 3 (P = .005).

CONCLUSIONS

The implementation of a standardized RH guideline improved compliance with a lung-protective ventilation strategy and utilization of the prone position and was associated with lower driving pressure during the first 3 days after ECMO initiation in subjects with refractory hypoxemia.

Extracorporeal Gas Exchange for Acute Respiratory Distress Syndrome: Open Questions, Controversies and Future Directions

Veno-venous extracorporeal membrane oxygenation (V-V ECMO) in acute respiratory distress syndrome (ARDS) improves gas exchange and allows lung rest, thus minimizing ventilation-induced lung injury. In the last forty years, a major technological and clinical improvement allowed to dramatically improve the outcome of patients treated with V-V ECMO. However, many aspects of the care of patients on V-V ECMO remain debated. In this review, we will focus on main issues and controversies on caring of ARDS patients on V-V ECMO support. Particularly, the indications to V-V ECMO and the feasibility of a less invasive extracorporeal carbon dioxide removal will be discussed. Moreover, the controversies on management of mechanical ventilation, prone position and sedation will be explored. In conclusion, we will discuss evidences on transfusions and management of anticoagulation, also focusing on patients who undergo simultaneous treatment with ECMO and renal replacement therapy. This review aims to discuss all these clinical aspects with an eye on future directions and perspectives.

Ultraprotective ventilation allowed by extracorporeal CO2 removal improves the right ventricular function in acute respiratory distress syndrome patients: a quasi-experimental pilot study

Background

Right ventricular (RV) failure is a common complication in moderate-to-severe acute respiratory distress syndrome (ARDS). RV failure is exacerbated by hypercapnic acidosis and overdistension induced by mechanical ventilation. Veno-venous extracorporeal CO₂ removal (ECCO₂R) might allow ultraprotective ventilation with lower tidal volume (V_T) and plateau pressure (P_plat). This study investigated whether ECCO₂R therapy could affect RV function.

Methods

This was a quasi-experimental prospective observational pilot study performed in a French medical ICU. Patients with moderate-to-severe ARDS with PaO₂/FiO₂ ratio between 80 and 150 mmHg were enrolled. An ultraprotective ventilation strategy was used with V_T at 4 mL/kg of predicted body weight during the 24 h following the start of a low-flow ECCO₂R device. RV function was assessed by transthoracic echocardiography (TTE) during the study protocol.

Results

The efficacy of ECCO₂R facilitated an ultraprotective strategy in all 18 patients included. We observed a significant improvement in RV systolic function parameters. Tricuspid annular plane systolic excursion (TAPSE) increased significantly under ultraprotective ventilation compared to baseline (from 22.8 to 25.4 mm; p < 0.05). Systolic excursion velocity (S’ wave) also increased after the 1-day protocol (from 13.8 m/s to 15.1 m/s; p < 0.05). A significant improvement in the aortic velocity time integral (VTIAo) under ultraprotective ventilation settings was observed (p = 0.05). There were no significant differences in the values of systolic pulmonary arterial pressure (sPAP) and RV preload.

Conclusion

Low-flow ECCO₂R facilitates an ultraprotective ventilation strategy thatwould improve RV function in moderate-to-severe ARDS patients. Improvement in RV contractility appears to be mainly due to a decrease in intrathoracic pressure allowed by ultraprotective ventilation, rather than a reduction of PaCO₂.

Indications and contraindications for extracorporeal life support for severe heart or lung failure: a systematic review

INTRODUCTION

The effectiveness of extracorporeal life support (ECLS) in critically ill patients remains unclear despite a substantial increase in its use. This study critically assesses existing ECLS guidelines, consensus statements, and position papers to systematically review them for agreements and differences regarding indications and contraindications for ECLS.

EVIDENCE ACQUISITION

The aims of this review were to identify available indications and contraindications for ECLS and to evaluate the quality of the evidence on which they are based. Documents containing recommendations regarding indications and/or contraindications for ECLS in adults (aged 18+) were identified through Medline, EMBASE, and CENTRAL searches. Additional documents were identified from guideline-specific databases and the internet websites of professional societies. Based on the Appraisal of Guidelines for Research and Evaluation (AGREE II), four independent reviewers assessed the rigor of development and quality of the documents.

EVIDENCE SYNTHESIS

Eleven documents met the inclusion criteria. Three documents received an average score of ≥50% in all domains. However, the Editorial independence domain only scored <50% in most of the documents. Overall, 13 cardiac and 13 pulmonary ECLS indications, and 23 cardiac and 14 pulmonary contraindications were identified. Indications and contraindications for ECLS use are variable across the documents included and leave considerable room for interpretation.

CONCLUSIONS

The documents included for review show considerable variability, with little consensus on indications and contraindications. This lack of consensus may reflect a lack of clarity regarding ECLS utility. Additionally, it may reveal the necessity for individualized, patient-dependent criteria supported by the best evidence available.

Prevalence and Risk Factors for Thrombotic Complications Following Venovenous Extracorporeal Membrane Oxygenation: A CT Scan Study

OBJECTIVES

The aims of this study were to: 1) analyze the cannula-associated deep vein thrombosis frequency after venovenous extracorporeal membrane oxygenation using a CT scan and 2) identify the associated risk factors for cannula-associated deep vein thrombosis.

DESIGN

Retrospective observational analysis at a single center.

SETTING

Tertiary referral university teaching hospital.

PATIENTS

Patients under venovenous extracorporeal membrane oxygenation with a femorofemoral or femorojugular cannulation admitted for acute respiratory distress syndrome or primary graft dysfunction after pulmonary transplantation. CT scan was performed within 4 days after decannulation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We included 105 of 228 patients screened. Bacterial pneumonia was the main indication of venovenous extracorporeal membrane oxygenation (46.7%). CT scans were performed at a median of 2 days (1-3 d) after decannulation. Cannula-associated deep vein thrombosis was found in 75 patients (71.4%) despite it having a mean activated partial thromboplastin time ratio of 1.60 ± 0.31. Femorofemoral cannulation induced femoral cannula-associated deep vein thrombosis more frequently than femorojugular cannulation (69.2% vs 63.1%, respectively; p = 0.04). Seventeen of the 105 patients (16.2%) had a pulmonary embolism. Multivariate logistic regression analysis showed that higher the percentage of thrombocytopenia less than 100 G/L during extracorporeal membrane oxygenation period, lower the risk for developing cannula-associated deep vein thrombosis (hazard ratio, 0.98; 95% CI, 0.98-1.00; p = 0.02).

CONCLUSIONS

Cannula-associated deep vein thrombosis after venovenous extracorporeal membrane oxygenation is a frequent complication. This plead for a systematic vascular axis imaging after venovenous extracorporeal membrane oxygenation. Thrombocytopenia is associated with a reduction in the occurrence of thrombotic events.

The use of ECMO in ICU. Recommendations of the Spanish Society of Critical Care Medicine and Coronary Units

The use of extracorporeal membrane oxygenation systems has increased significantly in recent years; given this reality, the Spanish Society of Critical Intensive Care Medicine and Coronary Units (SEMICYUC) has decided to draw up a series of recommendations that serve as a framework for the use of this technique in intensive care units. The three most frequent areas of extracorporeal membrane oxygenation systems use in our setting are: as a cardiocirculatory support, as a respiratory support and for the maintenance of the abdominal organs in donors. The SEMICYUC appointed a series of experts belonging to the three working groups involved (Cardiological Intensive Care and CPR, Acute Respiratory Failure and Transplant work group) that, after reviewing the existing literature until March 2018, developed a series of recommendations. These recommendations were posted on the SEMICYUC website to receive suggestions from the intensivists and finally approved by the Scientific Committee of the Society. The recommendations, based on current knowledge, are about which patients may be candidates for the technique, when to start it and the necessary infrastructure conditions of the hospital centers or, the conditions for transfer to centers with experience. Although from a physiopathological point of view, there are clear arguments for the use of extracorporeal membrane oxygenation systems, the current scientific evidence is weak, so studies are needed that define more precisely which patients benefit most from the technique and when they should start.

[Interhospital transport of patients with ARDS]

In patients with severely compromised gas exchange, interhospital transportation is frequently necessary due to the need to provide access to specialized care. Risks are inherent during transport, so the anticipated benefits of transportation must be weighed against the possible negative outcome during the transport. The use of specialized teams during transportation can help to reduce adverse events. Diligent planning of the transportation, monitoring and medical staff during transport can decrease adverse events and reduce risks. This article defines the group of patients that may benefit from referral. This article discusses the risks associated with the transportation of patients with severely impaired gas exchange and the risks related to different means of transportation. The decisions required before transportation are described as well as the practical approach starting at the transferring hospital until arrival at the admitting hospital.

Outcomes of extracorporeal membrane oxygenation in adult patients with hypoxemic respiratory failure refractory to mechanical ventilation

Introduction

Extracorporeal membrane oxygenation (ECMO) is a mode of extracorporeal life support that has been used to support cardiopulmonary disease refractory to conventional therapy. The experience with the use of ECMO in acute hypoxemic respiratory failure is still limited. The aim of this study was to report clinical outcomes in adult patients with acute hypoxemic respiratory failure refractory to mechanical ventilation treated with ECMO.

Methods

Between July 2011 and October 2017, 18 adult patients with hypoxemic respiratory failure refractory to mechanical ventilation were admitted to the Intensive Care Unit of an acute care tertiary hospital in Barcelona, Spain. These patients were treated with ECMO as salvage respiratory therapy. Outcomes included clinical data, ventilatory and blood gas characteristics, survival, and complications.

Results

Fifteen patients (83.3%) were previously treated in prone position. The indication of VV-ECMO was established at an early stage after a mean (SD) of 3.8 (2.5) days on mechanical ventilation. The mean duration of ECMO was 10.4 days, and 16 patients (88.9%) required venous cannulation, mostly femoral-internal jugular. The mean length of ICU stay was 27 days and the mean hospital stay was 42.1 days. The ICU survival rate was 55.5% (n = 10) and the hospital survival rate was 50% (n = 9).

Conclusions

This clinical study in a small series of ICU patients treated with ECMO confirms the usefulness of this technique as a ventilatory support in patients with refractory hypoxemic respiratory failure. However, the indication of this procedure is also committed to an ethical reflection considering the possible futility of the measure on a case-by-case basis and associated complications.

"Do not do" recommendations of the working groups of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) for the management of critically ill patients

The project "Commitment to Quality of Scientific Societies", promoted since 2013 by the Spanish Ministry of Health, seeks to reduce unnecessary health interventions that have not proven effective, have little or doubtful effectiveness, or are not cost-effective. The objective is to establish the "do not do" recommendations for the management of critically ill patients. A panel of experts from the 13 working groups (WGs) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) was selected and nominated by virtue of clinical expertise and/or scientific experience to carry out the recommendations. Available scientific literature in the management of adult critically ill patients from 2000 to 2017 was extracted. The clinical evidence was discussed and summarized by the experts in the course of consensus finding of each WG, and was finally approved by the WGs after an extensive internal review process carried out during the first semester of 2017. A total of 65 recommendations were developed, of which 5 corresponded to each of the 13 WGs. These recommendations are based on the opinion of experts and scientific knowledge, and aim to reduce those treatments or procedures that do not add value to the care process; avoid the exposure of critical patients to potential risks; and improve the adequacy of health resources.

Accidental hypothermia

Accidental hypothermia causes profound changes to the body's physiology. After an initial burst of agitation (e.g., 36-37°C), vital functions will slow down with further cooling, until they vanish (e.g. <20-25°C). Thus, a deeply hypothermic person may appear dead, but may still be able to be resuscitated if treated correctly. The hospital use of minimally invasive rewarming for nonarrested, otherwise healthy patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionized the management of hypothermic cardiac arrest, with survival rates approaching 100%. Hypothermic patients with risk factors for imminent cardiac arrest (i.e., temperature <28°C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS center. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanic CPR can be helpful. Intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern postresuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimize prehospital triage, transport, and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and postresuscitation care.

Efficacy and safety of argatroban in patients with acute respiratory distress syndrome and extracorporeal lung support

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) or pumpless extracorporeal lung assist (pECLA) requires effective anticoagulation. Knowledge on the use of argatroban in patients with acute respiratory distress syndrome (ARDS) undergoing ECMO or pECLA is limited. Therefore, this study assessed the feasibility, efficacy and safety of argatroban in critically ill ARDS patients undergoing extracorporeal lung support.

METHODS

This retrospective analysis included ARDS patients on extracorporeal lung support who received argatroban between 2007 and 2014 in a single ARDS referral center. As controls, patients who received heparin were matched for age, sex, body mass index and severity of illness scores. Major and minor bleeding complications, thromboembolic events, administered number of erythrocyte concentrates, thrombocytes and fresh-frozen plasmas were assessed. The number of extracorporeal circuit systems and extracorporeal lung support cannulas needed due to clotting was recorded. Also assessed was the efficacy to reach the targeted activated partial thromboplastin time (aPTT) in the first consecutive 14 days of therapy, and the controllability of aPTT values is within a therapeutic range of 50-75 s. Fisher's exact test, Mann-Whitney U tests, Friedman tests and multivariate nonparametric analyses for longitudinal data (MANOVA; Brunner's analysis) were applied where appropriate.

RESULTS

Of the 535 patients who met the inclusion criteria, 39 receiving argatroban and 39 matched patients receiving heparin (controls) were included. Baseline characteristics were similar between the two groups, including severity of illness and organ failure scores. There were no significant differences in major and minor bleeding complications. Rates of thromboembolic events were generally low and were similar between the two groups, as were the rates of transfusions required and device-associated complications. The controllability of both argatroban and heparin improved over time, with a significantly increasing probability to reach the targeted aPTT corridor over the first days (p < 0.001). Over time, there were significantly fewer aPTT values below the targeted aPTT goal in the argatroban group than in the heparin group (p < 0.05). Both argatroban and heparin reached therapeutic aPTT values for adequate application of extracorporeal lung support.

CONCLUSIONS

Argatroban appears to be a feasible, effective and safe anticoagulant for critically ill ARDS patients undergoing extracorporeal lung support.

Extracorporeal Membrane Oxygenation in New York State: Trends, Outcomes, and Implications for Patient Selection

BACKGROUND

Utilization of extracorporeal membrane oxygenation (ECMO) is expanding despite limited outcome data defining appropriate use.

METHODS AND RESULTS

To quantify determinants of early and 1-year survival after ECMO in adult patients, we conducted a retrospective cohort analysis of 1286 patients aged ≥18 years who underwent ECMO in New York State from 2003 to 2014. Median follow-up time was 4.9 months (range, 0-12 months). ECMO utilization increased from 13 patients in 8 hospitals in 2003 to 330 patients in 30 hospitals in 2014. Compared with patients undergoing ECMO before 2009, later patients were older (54.4 versus 52.3 years; P=0.013) and more likely to have major comorbidity including chronic kidney disease (25.2% versus 13.2%; P=0.02) and liver disease (20.0% versus 10.7%; P=0.001). In the overall cohort, 30-day mortality was 52.2% (95% confidence interval, 49.5-54.9). Mortality at 30 days was 65.2% for patients aged ≥75 years (n=73/112) and 74.6% in patients who required cardiopulmonary resuscitation (n=91/122). Survival at 1 year was 38.4% (95% confidence interval, 35.7-41.0). The 30-day mortality and 1-year survival improved across the study period. In multivariable analysis, earlier year of ECMO, lower hospital volume, indication for ECMO after a cardiac procedure, cardiopulmonary resuscitation before ECMO placement, and age >65 years were independent predictors of worse survival.

CONCLUSIONS

Outcomes of ECMO have improved despite increasing comorbidity. Extreme mortality after ECMO in elderly patients and patients requiring cardiopulmonary resuscitation indicates that less invasive therapeutic or palliative modalities may be more appropriate in this end-of-life setting.

[The role of extracorporeal removal of CO2 (ECCO2R) in the management of respiratory diseases]

INTRODUCTION

The aim of extracorporeal removal of CO₂ (ECCO₂R) is to ensure the removal of CO₂ without any significant effect on oxygenation. ECCO₂R makes use of low to moderate extracorporeal blood flow rates, whereas extracorporeal membrane oxygenation (ECMO) requires high blood flows.

STATE OF THE ART

For each ECCO₂R device it is important to consider not only performance in terms of CO₂ removal, but also cost and safety, including the incidence of hemolysis and of hemorrhagic and thrombotic complications. In addition, it is possible that the benefits of such techniques may extend beyond simple removal of CO₂. There have been preliminary reports of benefits in terms of reduced respiratory muscle workload. Mobilization of endothelial progenitor cells could also occur, in analogy to the data reported with ECMO, with a potential benefit in term of pulmonary repair. The most convincing clinical experience has been reported in the context of the acute respiratory distress syndrome (ARDS) and severe acute exacerbations of chronic obstructive pulmonary disease (COPD), especially in patients at high risk of failure of non-invasive ventilation.

PERSPECTIVES

Preliminary results prompt the initiation of randomized controlled trials in these two main indications. Finally, the development of these technologies opens new perspectives in terms of long-term ventilatory support.

Characteristics and provision of care of patients with the acute respiratory distress syndrome: descriptive findings from the DACAPO cohort baseline and comparison with international findings

BACKGROUND

Little is known about the characteristics and real world life circumstances of ARDS (acute respiratory distress syndrome) patient populations. This knowledge is essential for transferring evidence-based therapy into routine healthcare. The aim of this study was to report socio-demographic and clinical characteristics in an unselected population of ARDS patients and to compare these results to findings from other large ARDS cohorts.

METHODS

A German based cross-sectional observational study was carried out. A total of 700 ARDS patients were recruited in 59 study sites between September 2014 and January 2016. Socio-demographic, disease and care related variables were recorded. Additionally, characteristics of other large ARDS cohorts identified by a systematic literature search were extracted into evidence tables.

RESULTS

Median age of ARDS patients was 58 years, 69% were male. Sixty percent had no employment, predominantly due to retirement. Seventy-one percent lived with a partner. The main cause of ARDS was a pulmonary 'direct' origin (79%). The distribution of severity was as follows: mild (14%), moderate (48%), severe (38%). Overall ICU mortality was calculated to be 34%. The observed prevalence of critical events (hypoxemia, hypoglycemia, re-intubation) was 47%. Supportive measures during ICU-treatment were applied to 60% of the patients. Other ARDS cohorts revealed a high heterogeneity in reported concomitant diseases, but sepsis and pneumonia were most frequently reported. Mean age ranged from 54 to 71 years and most patients were male. Other socio-demographic factors have been almost neglected.

CONCLUSIONS

The proportion of patients suffering of mild ARDS was lower compared to the only study identified, which also applied the Berlin definition. The frequency of critical events during ICU treatment was high and the implementation of evidence-based therapy (prone positioning, neuro-muscular blockers) was limited. More evidence on socio-demographic characteristics and further studies applying the current diagnostic criteria are desirable.

Dynamic driving pressure associated mortality in acute respiratory distress syndrome with extracorporeal membrane oxygenation

Background

The survival predictors and optimal mechanical ventilator settings in patients with severe acute respiratory distress syndrome (ARDS) undergoing extracorporeal membrane oxygenation (ECMO) are uncertain. This study was designed to investigate the influences of clinical variables and mechanical ventilation settings on the outcomes for severe ARDS patients receiving ECMO.

Methods

We reviewed severe ARDS patients who received ECMO due to refractory hypoxemia from May 2006 to October 2015. Serial mechanical ventilator settings before and after ECMO and factors associated with survival were analyzed.

Results

A total of 158 severe ARDS patients received ECMO were finally analyzed. Overall intensive care unit (ICU) mortality was 55.1%. After ECMO initiation, tidal volume, peak inspiratory pressure and dynamic driving pressure were decreased, while positive end-expiratory pressure levels were relative maintained. After ECMO initiation, nonsurvivors had significantly higher dynamic driving pressure until day 7 than survivors. Cox proportional hazards regression model revealed that immunocompromised [hazard ratio 1.957; 95% confidence interval (CI) 1.216–3.147; p = 0.006], Acute Physiology and Chronic Health Evaluation (APACHE) II score (hazard ratio 1.039; 95% CI 1.005–1.073; p = 0.023), ARDS duration before ECMO (hazard ratio 1.002; 95% CI 1.000–1.003; p = 0.029) and mean dynamic driving pressure from day 1 to 3 on ECMO (hazard ratio 1.070; 95% CI 1.026–1.116; p = 0.002) were independently associated with ICU mortality.

Conclusions

For severe ARDS patients receiving ECMO, immunocompromised status, APACHE II score and the duration of ARDS before ECMO initiation were significantly associated with ICU survival. Higher dynamic driving pressure during first 3 days of ECMO support was also independently associated with increased ICU mortality.

Development of the first adult respiratory extracorporeal membrane oxygenation center in Croatia under emergency circumstances

INTRODUCTION

We report on the challenges of establishing a successful adult respiratory extracorporeal membrane oxygenation (ECMO) center in a developing country like Croatia under emergency conditions. We further introduce measures that would improve the outcome of patients treated with ECMO for respiratory failure at the national level.

METHODS

100 consecutive adult patients treated with venovenous (VV) ECMO for acute respiratory failure were enrolled to the database prospectively from October 2009 until June 2016. A review of methodology in establishing an adult respiratory ECMO center is provided.

RESULTS

7 years after the establishment of the first respiratory ECMO center in Croatia the hospital mortality was 44% and ECMO procedure survival was 71%. With this data, our results are comparable to an average extracorporeal life support organization (ELSO) center.

CONCLUSIONS

Our results demonstrate that a successful adult respiratory ECMO center can be established under emergency conditions even in less developed countries like Croatia. Today Croatia's respiratory ECMO network is insufficiently organized and the Ministry of Health should provide a comprehensive, national, ECMO network strategy. Currently, and contrary to the opinion of the world's leading experts, any hospital in Croatia is allowed to perform the ECMO procedure without any control or validation. Only if health-policy makers in Croatia reconsider this issue will we be able to provide the best care possible for respiratory ECMO patients at the national level.

[Extracorporeal CO2 removal as life support system for a severe organizing pneumonia]

INTRODUCTION

Acute lung injuries are usually found in intensive care unit. The diffuse alveolar damage (DAD) is the associated histological pattern and the most severe end-stage of the disease. Organizing pneumonia (OP), for which corticosteroids are the reference therapy, can mimic DAD. While postponing the response to treatment, to limit mechanical ventilation side effects, extracorporeal membrane oxygene can be proposed. We present a case of a severe OP for which extracorporeal CO₂ removal (ECCO₂R) is used as a bridge to recovery under corticosteroid therapy.

CASE REPORT

In the context of a flu-like syndrome, the non-recovery of a lung impairment is reported to a severe OP. ECCO₂R is applied when using an ultraprotective ventilation and while waiting for lung healing under corticosteroid. This strategy allowed successful recovery, early physical therapy and active mobilization.

CONCLUSION

This observation presents the diagnostic and therapeutic difficulties of the lung parenchymental disease in intensive care. OP must be recognized. ECCO₂R can be used in severe OP as a bridge to recovery while waiting for the corticosteroid efficacy.

Venovenous extracorporeal membrane oxygenation for ARDS: outcome analysis of a Croatian referral center for respiratory ECMO

BACKGROUND

The use of venovenous extracorporeal membrane oxygenation (VV-ECMO) as a rescue therapy in severe acute respiratory distress syndrome (ARDS) has become well established; however, the affirmation of evidence on VV-ECMO application and the analysis of patient outcomes after VV-ECMO treatment for ARDS continues. The aim of the study is to identify variables that affected the outcome of patients treated with VV-ECMO for severe ARDS outside a major ECMO center.

METHODS

The study included adult patients with severe ARDS treated with ECMO at a tertiary care hospital in Zagreb, Croatia between October 2009 and July 2014. Patients were recruited from a prospective database.

RESULTS

The study enrolled 40 patients, 20 of whom had H1N1-induced ARDS. The hospital mortality was 38%. The difference in mortality and long-term outcome in H1N1-induced ARDS as compared to non-H1N1-induced ARDS was not significant. Variables associated with mortality included immunosuppression, shock at time of admission, acute renal failure, occurrence of heparin-induced thrombocytopenia antibodies, nosocomial sepsis and duration of ECMO.

CONCLUSIONS

The results of our study indicate that ECMO use in severe ARDS is feasible with low mortality and identify or assert the variables associated with adverse outcomes.

Early antibiotics administration during targeted temperature management after out-of-hospital cardiac arrest: a nationwide database study

Background

Patients resuscitated after cardiac arrest are reportedly at high risk for infection and sepsis, especially those treated with targeted temperature management (TTM). There is, however, limited evidence suggesting that early antibiotic use improves patient outcomes. We examined the hypothesis that early treatment with antibiotics reduces mortality in patients with cardiac arrest receiving TTM.

Methods

We identified 2803 patients with cardiogenic out-of-hospital cardiac arrest (OHCA) that were treated with TTM and were admitted to 371 hospitals that contribute to the Japanese Diagnosis Procedure Combination inpatient database between July 2007 and March 2013. Of these, 1272 received antibiotics within the first 2 days (antibiotics) and 1531 did not (control). We generated 802 propensity score-matched pairs.

Results

There was no significant difference in 30-day mortality between the groups (control vs. antibiotics; 33.0 % vs. 29.9 %; difference, 3.1 %; 95 % confidence interval [CI], −1.4 to 7.7 %, p = 0.18). Analysis using the hospital antibiotics prescribing rate as an instrumental variable showed that antibiotic use was not significantly associated with a reduction in 30-day mortality (6.6 %, CI 95 %, −0.5 to 13.7 %, p = 0.28). A subgroup analysis of patients who required extracorporeal membrane oxygenation (ECMO) indicated a significant difference in 30-day mortality between the 2 groups (62.9 % vs. 43.5 %; difference 19.3 %, CI 95 %, 5.9 to 32.7 %, p = 0.005). In the instrumental variable model, the estimated reduction in 30-day mortality associated with antibiotics was 18.2 % (CI 95 %, 21.3 to 34.4 %, p = 0.03) in ECMO patients.

Conclusions

Although there was no significant association between the use of antibiotics and mortality after overall cardiogenic OHCA treated with TTM, antibiotics may be beneficial in patients who require ECMO.

Extracorporeal membrane oxygenation treatment of a H7N9-caused respiratory failure patient with mechanical valves replacement history: A case report

BACKGROUND

Patients with respiratory failure caused by H7N9 may benefit from veno-venous, veno-arterial, and veno-veno-arterial extracorporeal membrane oxygenation (ECMO) support.

CASE SUMMARY

A 55-year-old male patient was suffering from H7N9-caused acute respiratory distress syndrome (ARDS). He had a mechanical mitral and aortic valve replacement surgery and was using warfarin for anticoagulation. After prolonged mechanical ventilation, oxygen saturation was not improved. Veno-veno ECMO was then applied. After 16 days of extracorporeal life support, the patient successfully weaned from ECMO, with relatively good pulmonary recovery.

CONCLUSION

This report demonstrates that ECMO support can help treating life-threatening diseases such as H7N9-associated ARDS. Because of his special mitral and aortic valve replacement surgery history and long duration of mechanical ventilation before ECMO, we report it as a separate case, hoping to provide some reference for ECMO treatment.

Accidental hypothermia-an update : The content of this review is endorsed by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM)

BACKGROUND

This paper provides an up-to-date review of the management and outcome of accidental hypothermia patients with and without cardiac arrest.

METHODS

The authors reviewed the relevant literature in their specialist field. Summaries were merged, discussed and approved to produce this narrative review.

RESULTS

The hospital use of minimally-invasive rewarming for non-arrested, otherwise healthy, patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionised the management of hypothermic cardiac arrest, with survival rates approaching 100 % in some cases. Hypothermic patients with risk factors for imminent cardiac arrest (temperature <28 °C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS-centre. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanical CPR can be helpful. Delayed or intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern post-resuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimise pre-hospital triage, transport and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and post-resuscitation care.

CONCLUSIONS

Based on new evidence, additional clinical experience and clearer management guidelines and documentation, the treatment of accidental hypothermia has been refined. ECLS has substantially improved survival and is the treatment of choice in the patient with unstable circulation or cardiac arrest.

Runtime and aPTT predict venous thrombosis and thromboembolism in patients on extracorporeal membrane oxygenation: a retrospective analysis

Background

Even though bleeding and thromboembolic events are major complications of extracorporeal membrane oxygenation (ECMO), data on the incidence of venous thrombosis (VT) and thromboembolism (VTE) under ECMO are scarce. This study analyzes the incidence and predictors of VTE in patients treated with ECMO due to respiratory failure.

Methods

Retrospective analysis of patients treated on ECMO in our center from 04/2010 to 11/2015. Patients with thromboembolic events prior to admission were excluded. Diagnosis was made by imaging in survivors and postmortem examination in deceased patients.

Results

Out of 102 screened cases, 42 survivors and 21 autopsy cases [mean age 46.0 ± 14.4 years; 37 (58.7 %) males] fulfilling the above-mentioned criteria were included. Thirty-four patients (54.0 %) underwent ECMO therapy due to ARDS, and 29 patients (46.0 %) with chronic organ failure were bridged to lung transplantation. Despite systemic anticoagulation at a mean PTT of 50.6 ± 12.8 s, [VT/VTE 47.0 ± 12.3 s and no VT/VTE 53.63 ± 12.51 s (p = 0.037)], VT and/or VTE was observed in 29 cases (46.1 %). The rate of V. cava thrombosis was 15/29 (51.7 %). Diagnosis of pulmonary embolism prevailed in deceased patients [5/21 (23.8 %) vs. 2/42 (4.8 %) (p = 0.036)]. In a multivariable analysis, only aPTT and time on ECMO predicted VT/VTE. There was no difference in the incidence of clinically diagnosed VT in ECMO survivors and autopsy findings.

Conclusions

Venous thrombosis and thromboembolism following ECMO therapy are frequent. Quality of anticoagulation and ECMO runtime predicted thromboembolic events.

Extracorporeal carbon dioxide removal (ECCO2R) in respiratory deficiency and current investigations on its improvement: a review

The implementation of extracorporeal carbon dioxide removal (ECCO₂R) as one of the extracorporeal life support system is getting more attention today. Thus, the objectives of this paper are to study the clinical practice of commercial ECCO₂R system, current trend of its development and also the perspective on future improvement that can be done to the existing ECCO₂R system. The strength of this article lies in its review scope, which focuses on the commercial ECCO₂R therapy in the market based on membrane lung and current investigation to improve the efficiency of the ECCO₂R system, in terms of surface modification by carbonic anhydrase (CA) immobilization technique and respiratory electrodialysis (R-ED). Our methodology approach involves the identification of relevant published literature from PubMed and Web of Sciences search engine using the terms Extracorporeal Carbon Dioxide Removal (ECCO₂R), Extracorporeal life support, by combining terms between ECCO₂R and CA and also ECCO₂R with R-ED. This identification only limits articles in English language. Overall, several commercial ECCO₂R systems are known and proven safe to be used in patients in terms of efficiency, safety and risk of complication. In addition, CA-modified hollow fiber for membrane lung and R-ED are proven to have good potential to be applied in conventional ECCO₂R design. The detailed technique and current progress on CA immobilization and R-ED development were also reviewed in this article.

The standard of care of patients with ARDS: ventilatory settings and rescue therapies for refractory hypoxemia

Purpose

Severe ARDS is often associated with refractory hypoxemia, and early identification and treatment of hypoxemia is mandatory. For the management of severe ARDS ventilator settings, positioning therapy, infection control, and supportive measures are essential to improve survival.

Methods and results

A precise definition of life-threating hypoxemia is not identified. Typical clinical determinations are: arterial partial pressure of oxygen < 60 mmHg and/or arterial oxygenation < 88 % and/or the ratio of PaO₂/FIO₂ < 100. For mechanical ventilation specific settings are recommended: limitation of tidal volume (6 ml/kg predicted body weight), adequate high PEEP (>12 cmH₂O), a recruitment manoeuvre in special situations, and a ‘balanced’ respiratory rate (20-30/min). Individual bedside methods to guide PEEP/recruitment (e.g., transpulmonary pressure) are not (yet) available. Prone positioning [early (≤ 48 hrs after onset of severe ARDS) and prolonged (repetition of 16-hr-sessions)] improves survival. An advanced infection management/control includes early diagnosis of bacterial, atypical, viral and fungal specimen (blood culture, bronchoalveolar lavage), and of infection sources by CT scan, followed by administration of broad-spectrum anti-infectives. Neuromuscular blockage (Cisatracurium ≤ 48 hrs after onset of ARDS), as well as an adequate sedation strategy (score guided) is an important supportive therapy. A negative fluid balance is associated with improved lung function and the use of hemofiltration might be indicated for specific indications.

Conclusions

A specific standard of care is required for the management of severe ARDS with refractory hypoxemia.

Experts' opinion on management of hemodynamics in ARDS patients: focus on the effects of mechanical ventilation

RATIONALE

Acute respiratory distress syndrome (ARDS) is frequently associated with hemodynamic instability which appears as the main factor associated with mortality. Shock is driven by pulmonary hypertension, deleterious effects of mechanical ventilation (MV) on right ventricular (RV) function, and associated-sepsis. Hemodynamic effects of ventilation are due to changes in pleural pressure (Ppl) and changes in transpulmonary pressure (TP). TP affects RV afterload, whereas changes in Ppl affect venous return. Tidal forces and positive end-expiratory pressure (PEEP) increase pulmonary vascular resistance (PVR) in direct proportion to their effects on mean airway pressure (mPaw). The acutely injured lung has a reduced capacity to accommodate flowing blood and increases of blood flow accentuate fluid filtration. The dynamics of vascular pressure may contribute to ventilator-induced injury (VILI). In order to optimize perfusion, improve gas exchange, and minimize VILI risk, monitoring hemodynamics is important.

RESULTS

During passive ventilation pulse pressure variations are a predictor of fluid responsiveness when conditions to ensure its validity are observed, but may also reflect afterload effects of MV. Central venous pressure can be helpful to monitor the response of RV function to treatment. Echocardiography is suitable to visualize the RV and to detect acute cor pulmonale (ACP), which occurs in 20-25 % of cases. Inserting a pulmonary artery catheter may be useful to measure/calculate pulmonary artery pressure, pulmonary and systemic vascular resistance, and cardiac output. These last two indexes may be misleading, however, in cases of West zones 2 or 1 and tricuspid regurgitation associated with RV dilatation. Transpulmonary thermodilution may be useful to evaluate extravascular lung water and the pulmonary vascular permeability index. To ensure adequate intravascular volume is the first goal of hemodynamic support in patients with shock. The benefit and risk balance of fluid expansion has to be carefully evaluated since it may improve systemic perfusion but also may decrease ventilator-free days, increase pulmonary edema, and promote RV failure. ACP can be prevented or treated by applying RV protective MV (low driving pressure, limited hypercapnia, PEEP adapted to lung recruitability) and by prone positioning. In cases of shock that do not respond to intravascular fluid administration, norepinephrine infusion and vasodilators inhalation may improve RV function. Extracorporeal membrane oxygenation (ECMO) has the potential to be the cause of, as well as a remedy for, hemodynamic problems. Continuous thermodilution-based and pulse contour analysis-based cardiac output monitoring are not recommended in patients treated with ECMO, since the results are frequently inaccurate. Extracorporeal CO2 removal, which could have the capability to reduce hypercapnia/acidosis-induced ACP, cannot currently be recommended because of the lack of sufficient data.

Extracorporeal Membrane Oxygenation and the Kidney

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is an effective therapy for patients with reversible cardiac and/or respiratory failure. Acute kidney injury (AKI) often occurs in patients supported with ECMO; it frequently evolves into chronic kidney damage or end-stage renal disease and is associated with a reported 4-fold increase in mortality rate. Although AKI is generally due to the hemodynamic alterations associated with the baseline disease, ECMO itself may contribute to maintaining kidney dysfunction through several mechanisms.

SUMMARY

AKI may be related to conditions derived from or associated with extracorporeal therapy, leading to a reduction in renal oxygen delivery and/or to inflammatory damage. In particular, during pathological conditions requiring ECMO, the biological defense mechanisms maintaining central perfusion by a reduction of perfusion to peripheral organs (such as the kidney) have been identified as pretreatment and patient-related risk factors for AKI. Hormonal pathways are also impaired in patients supported with ECMO, leading to failures in mechanisms of renal homeostasis and worsening fluid overload. Finally, inflammatory damage, due to the primary disease, heart and lung crosstalk with the kidney or associated with extracorporeal therapy itself, may further increase the susceptibility to AKI. Renal replacement therapy can be integrated into the main extracorporeal circuit during ECMO to provide for optimal fluid management and removal of inflammatory mediators.

KEY MESSAGES

AKI is frequently observed in patients supported with ECMO. The pathophysiology of the associated AKI is chiefly related to a reduction in renal oxygen delivery and/or to inflammatory damage. Risk factors for AKI are associated with a patient's underlying disease and ECMO-related conditions.

Right over left ventricular end-diastolic area relevance to predict hemodynamic intolerance of high-frequency oscillatory ventilation in patients with severe ARDS

Background

High-frequency oscillatory ventilation (HFOV) does not improve the prognosis of ARDS patients despite an improvement in oxygenation. This paradox may partly be explained by HFOV hemodynamic side-effects on right ventricular function. Our goal was to study the link between HFOV and hemodynamic effects and to test if the pre-HFOV right over left ventricular end-diastolic area (RVEDA/LVEDA) ratio, as a simple parameter of afterload-related RV dysfunction, could be used to predict HFOV hemodynamic intolerance in patients with severe ARDS.

Methods

Twenty-four patients were studied just before and within 3 h of HFOV using transthoracic echocardiography and transpulmonary thermodilution.

Results

Before HFOV, the mean PaO₂/FiO₂ ratio was 89 ± 23. The number of patients with a RVEDA/LVEDA ratio >0.6 significantly increased after HFOV [11 (46 %) vs. 17 (71 %)]. Although HFOV did not significantly decrease the arterial pressure (systolic, diastolic, mean and pulse pressure), it significantly decreased the cardiac index (CI) by 13 ± 18 % and significantly increased the RVEDA/LVEDA ratio by 14 ± 11 %. A significant correlation was observed between pre-HFOV RVEDA/LVEDA ratio and CI diminution after HFOV (r = 0.78; p < 0.0001). A RVEDA/LVEDA ratio superior to 0.6 resulted in a CI decrease >15 % during HFOV with a sensitivity of 80 % (95 % confidence interval 44–98 %) and a specificity of 79 % (confidence interval 49–95 %).

Conclusion

The RVEDA/LVEDA ratio measured just before HFOV predicts the hemodynamic intolerance of this technique in patients with severe ARDS. A high ratio under CMV raises questions about the use of HFOV in such patients.

Trial registration: ClinicalTrials.gov: NCT01167621

Update on the Extracorporeal Life Support

Extracorporeal life support (ECLS) is a type of cardiopulmonary bypass. It is an artificial means of supplying oxygen and removing CO₂ on behalf of damaged lungs while patients are recovering from underlying diseases. Recently, the use of ECLS is rapidly increasing as this machine becomes smaller, less invasive and easier to use. In addition, the improvement of clinicians' technique and outcome is increasing their application to patients with acute respiratory distress. In this regard, the purpose of this review is to introduce the physiological principles, risk factors, and advantages of ECLS, clinical rationale for using ECLS, ventilatory strategy during ECLS, which are still causing different opinions, the weaning from ECLS, and the use of anticoagulant.