Mechanical ventilation during extracorporeal membrane oxygenation

Mechanical ventilation settings during weaning from venovenous extracorporeal membrane oxygenation

BACKGROUND

The optimal timing of weaning from venovenous extracorporeal membrane oxygenation (VV ECMO) and its modalities have been rarely studied.

METHODS

Retrospective, multicenter cohort study over 7 years in two tertiary ICUs, high-volume ECMO centers in France and Italy. Patients with ARDS on ECMO and successfully weaned from VV ECMO were classified based on their mechanical ventilation modality during the sweep gas-off trial (SGOT) with either controlled mechanical ventilation or spontaneous breathing (i.e. pressure support ventilation). The primary endpoint was the time to successful weaning from mechanical ventilation within 90 days post-ECMO weaning.

RESULTS

292 adult patients with severe ARDS were weaned from controlled ventilation, and 101 were on spontaneous breathing during SGOT. The 90-day probability of successful weaning from mechanical ventilation was not significantly different between the two groups (sHR [95% CI], 1.23 [0.84-1.82]). ECMO-related complications were not statistically different between patients receiving these two mechanical ventilation strategies. After adjusting for covariates, older age, higher pre-ECMO sequential organ failure assessment score, pneumothorax, ventilator-associated pneumonia, and renal replacement therapy, but not mechanical ventilation modalities during SGOT, were independently associated with a lower probability of successful weaning from mechanical ventilation after ECMO weaning.

CONCLUSIONS

Time to successful weaning from mechanical ventilation within 90 days post-ECMO was not associated with the mechanical ventilation strategy used during SGOT. Further research is needed to assess the optimal ventilation strategy during weaning off VV ECMO and its impact on short- and long-term outcomes.

Extracorporal Membrane Oxygenation in Massive Pulmonary Embolism

BACKGROUND

Massive pulmonary embolism (MPE) carries significant 30-day mortality risk, and a change in societal guidelines has promoted the increasing use of extracorporeal membrane oxygenation (ECMO) in the immediate management of MPE-associated cardiovascular shock. This narrative review examines the current status of ECMO in MPE.

METHODS

A literature review was performed from 1982 to 2022 searching for the terms "Pulmonary embolism" and "ECMO," and the search was refined by examining those publications that covered MPE.

RESULTS

In the patient with MPE, veno-arterial ECMO is now recommended as a bridge to interventional therapy. It can reliably decrease right ventricular overload, improve RV function, and allow hemodynamic stability and restoration of tissue oxygenation. The use of ECMO in MPE has been associated with lower mortality in registry reviews, but there has been no significant difference in outcomes between patients treated with and without ECMO in meta-analyses. Applying ECMO is also associated with substantial multisystem morbidity due to systemic inflammatory response, bleeding with coagulopathy, hemorrhagic stroke, renal dysfunction, and acute limb ischemia, which must be factored into the outcomes.

CONCLUSIONS

The application of ECMO in MPE should be combined with an aggressive interventional pulmonary interventional program and should strictly adhere to the current selection criteria.

Tailoring the Best Positive End-Expiratory Pressure Through Invasive Right Ventricular Pressure-Volume Loops in a Patient Supported by Veno-Arterial Extracorporeal Membrane Oxygenation

Patients undergoing veno-arterial extracorporeal membrane oxygenation (VA-ECMO) typically suffer from cardiogenic pulmonary edema and lung atelectasis, which can exacerbate right ventricular (RV) dysfunction through an increase in lung elastance and RV afterload. Invasive mechanical ventilation settings, and positive end-expiratory pressure (PEEP) in particular, can help to improve RV performance by optimizing lung recruitment and minimizing alveolar overdistention. In this report, we present a VA-ECMO supported patient in whom in vivo RV pressure-volume (PV) loops were measured during a decremental PEEP trial, leading to the identification of an optimum PEEP level from a cardio-respiratory viewpoint. This innovative approach of tailoring mechanical ventilation settings according to cardio-respiratory physiology through in vivo RV PV loops may provide a novel way to optimize hemodynamics and patient outcomes.

Perioperative Extracorporeal Cardiopulmonary Resuscitation in Adult Patients: A Review for the Perioperative Physician

The use of extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest has grown rapidly over the previous decade. Considerations for the implementation and management of extracorporeal cardiopulmonary resuscitation are presented for the perioperative physician.

Complex Heart-Lung Ventilator Emergencies in the CICU

This review aims to enhance the comprehension and management of cardiopulmonary interactions in critically ill patients with cardiovascular disease undergoing mechanical ventilation. Highlighting the significance of maintaining a delicate balance, this article emphasizes the crucial role of adjusting ventilation parameters based on both invasive and noninvasive monitoring. It provides recommendations for the induction and liberation from mechanical ventilation. Special attention is given to the identification of auto-PEEP (positive end-expiratory pressure) and other situations that may impact hemodynamics and patients' outcomes.

Kinetics of C-reactive protein during extracorporeal membrane oxygenation

BACKGROUND

The exposure of blood to the artificial circuit during extracorporeal membrane oxygenation (ECMO) can induce an inflammatory response. C-reactive protein (CRP) is a commonly used biomarker of systemic inflammation.

METHODS

In this retrospective observational study, we analyzed results of daily plasma CRP measurements in 110 critically ill patients, treated with ECMO. We compared CRP levels during the first 5 days of ECMO operation, between different groups of patients according to ECMO configurations, Coronavirus disease 2019 (COVID-19) status, and mechanical ventilation parameters.

RESULTS

There was a statistically significant decrease in CRP levels during the first 5 days of veno-venous (VV) ECMO (173 ± 111 mg/L, 154 ± 107 mg/L, 127 ± 97 mg/L, 114 ± 100 mg/L and 118 ± 90 mg/L for days 1-5 respectively, p < 0.001). Simultaneously, there was a significant reduction in ventilatory parameters, as represented by the mechanical power (MP) calculation, from 24.02 ± 14.53 J/min to 6.18 ± 4.22 J/min within 3 h of VV ECMO initiation (p < 0.001). There was non-significant trend of increase in CRP level during the first 5 days of veno arterial (VA) ECMO (123 ± 80 mg/L, 179 ± 91 mg/L, 203 ± 90 mg/L, 179 ± 95 mg/L and 198 ± 93 for days 1-5 respectively, p = 0.126) and no significant change in calculated MP (from 14.28 ± 8.56 J/min to 10.81 ± 8.09 J/min within 3 h if ECMO initiation, p = 0.071).

CONCLUSIONS

We observed a significant decrease in CRP levels during the first 5 days of VV ECMO support, and suggest that the concomitant reduction in ventilatory MP may have mitigated the degree of alveolar stress and strain that could have contributed to a decrease in the systemic inflammatory process.

Liberation From Venovenous Extracorporeal Membrane Oxygenation for Respiratory Failure: A Scoping Review

BACKGROUND

Safe and timely liberation from venovenous extracorporeal membrane oxygenation (ECMO) would be expected to reduce the duration of ECMO, the risk of complications, and costs. However, how to liberate patients from venovenous ECMO effectively remains understudied.

RESEARCH QUESTION

What is the current state of the evidence on liberation from venovenous ECMO?

STUDY DESIGN AND METHODS

We systematically searched for relevant publications on liberation from venovenous ECMO in Medline and EMBASE. Citations were included if the manuscripts provided any of the following: criteria for readiness for liberation, a liberation protocol, or a definition of successful decannulation or decannulation failure. We included randomized trials, observational trials, narrative reviews, guidelines, editorials, and commentaries. We excluded single case reports and citations where the full text was unavailable.

RESULTS

We screened 1,467 citations to identify 39 key publications on liberation from venovenous ECMO. We then summarized the data into five main topics: current strategies used for liberation, criteria used to define readiness for liberation, conducting liberation trials, criteria used to proceed with decannulation, and parameters used to predict decannulation outcomes.

INTERPRETATION

Practices on liberation from venovenous ECMO are heterogeneous and are influenced strongly by clinician preference. Additional research on liberation thresholds is needed to define optimal liberation strategies and to close existing knowledge gaps in essential topics on liberation from venovenous ECMO.

The Role of Extracorporeal Membrane Oxygenation ECMO in Accidental Hypothermia and Rewarming in Out-of-Hospital Cardiac Arrest Patients-A Literature Review

Accidental hypothermia, defined as an unintentional drop of the body core temperature below 35 °C, is one of the causes of cardiocirculatory instability and reversible cardiac arrest. Currently, extracorporeal life support (ECLS) rewarming is recommended as a first-line treatment for hypothermic cardiac arrest patients. The aim of the ECLS rewarming is not only rapid normalization of core temperature but also maintenance of adequate organ perfusion. Veno-arterial extracorporeal membrane oxygenation (ECMO) is a preferred technique due to its lower anticoagulation requirements and potential to prolong circulatory support. Although highly efficient, ECMO is acknowledged as an invasive treatment option, requiring experienced medical personnel and is associated with the risk of serious complications. In this review, we aimed to discuss the clinical aspects of ECMO management in severely hypothermic cardiac arrest patients.

Whole-process respiratory management strategies based on electrical impedance tomography in a pregnant woman with diffuse alveolar hemorrhage induced by systemic lupus erythematosus under veno-venous extracorporeal membrane oxygenation

Electrical impedance tomography (EIT) as a bedside, noninvasive, radiation-free technology, could quantify alveolar collapse and over-distension and provide real-time ventilation images of lungs. Clinical studies have shown potential benefit in reducing lung injury by EIT to guide mechanical ventilation setting in acute respiratory distress syndrome (ARDS). The respiratory management of ARDS with venous-venous extracorporeal membrane oxygenation (VV ECMO) remains a challenge for ICU doctors. Moreover, EIT has gained great interests in the respiratory management in VV ECMO therapy. Here, EIT was used for respiratory management in the presented case of a 36-year-old gravida with systemic lupus erythematosus, who developed severe hypoxia caused by diffuse alveolar hemorrhage. Although the patient received mechanical ventilation, VV ECMO was further used for the refractory respiratory failure. EIT was applied to titrate positive end-expiratory pressure (PEEP), guide prone position and early mobilization, dynamic evaluating lung development during ECMO therapy. She was successfully rescued after comprehensive therapy. In summary, an EIT-guided whole-process respiratory management strategy that included PEEP titration, prone position, early mobilization, and dynamic lung ventilation monitoring was proposed. This case demonstrated that EIT-guided whole-process respiratory management strategy was feasible in the respiratory failure patient with VV ECMO therapy.

Patient-centered weaning from venoarterial extracorporeal membrane oxygenation: "A practice-oriented narrative review of literature"

Venoarterial extracorporeal membrane oxygenation (V-A ECMO) is increasingly used in cardiogenic shock for rapid stabilization and bridging towards recovery, long-term mechanical circulatory support or transplant. Although technological advances have instigated its widespread use, the complex, long-lasting ECMO care creates a significant strain on hospital staff and resources. Therefore, optimal clinical management including timely decisions on ECMO removal and further therapy are pivotal, yet require a well-structured weaning approach. Although dedicated guidelines are lacking, a variety of weaning protocols have distillated echocardiographic and hemodynamic predictors for successful weaning. Nevertheless, a strikingly high mortality up to 70% after initial successful weaning raises concerns about the validity of current weaning strategies. Here, we plead for a patient-tailored approach including a bailout strategy when weaning fails. This should account not only for left- but also right ventricular function and interdependence, as well as the temporal course of cardiac recovery in function of extracorporeal support. Patients with a high risk of weaning failure should be identified early, enabling timely transportation to an advanced heart failure center. This review summarizes predictors of successful weaning and discusses all relevant elements for a structured weaning approach with a central role for patient-specific clinical considerations and echocardiography.

Early extubation in extracorporeal life support patients: A propensity score-matched study

BACKGROUND

Extubation strategy in extracorporeal life support patients remains unclear, and literature only reports studies with significant biases.

OBJECTIVES

To explore the prognostic impact of an early ventilator-weaning strategy in assisted patients after controlling for confounding factors.

METHODS

A 10-year retrospective study included 241 patients receiving extracorporeal life support for at least 48 h, corresponding to a total of 977 days spent on assistance. The a priori probability of extubation for each day of assistance was calculated according to daily biological examinations, drug doses, clinical observations, and admission data to pair each day containing an extubation with one on which the patient was not extubated. The primary outcome was survival at day 28. The secondary outcomes were survival at day 7, respiratory infections, and safety criteria.

RESULTS

Two similar cohorts of 61 patients were generated. Survival at day 28 was better in patients extubated under assistance in univariate and multivariate (HR = 0.37 [0.2-0.68], p-value = 0.002) analyses. Patients who underwent failed early extubation did not have a different prognosis from those without early extubation. Successful early extubation was associated with a better outcome than a failed or no attempt at early extubation. Survival at day 7 and the rate of respiratory infections were better in early-extubated patients. Safety data did not differ between the two groups.

CONCLUSIONS

Early extubation during assistance was associated with a superior outcome in our propensity-matched cohort study. The safety data were reassuring. However, due to the lack of prospective randomized studies, the causality remains uncertain.

Optimal positive end-expiratory pressure reduces right ventricular dysfunction in COVID-19 patients on venovenous extracorporeal membrane oxygenation: A retrospective single-center study

While mechanical ventilation practices on venovenous extracorporeal membrane oxygenation (VV ECMO) are variable, most institutions utilize a lung rest strategy utilizing relatively low positive end-expiratory pressure (PEEP). The effect of PEEP titration using esophageal manometry during VV ECMO on pulmonary and cardiac function is unknown. This was a retrospective study of 69 patients initiated on VV ECMO between March 2020 through November 2021. Patients underwent standard PEEP (typically 10 cm H₂O) or optimal PEEP (PEEP titrated to an end-expiratory transpulmonary pressure 0-3 cm H₂O) throughout the ECMO run. The optimal PEEP strategy had higher levels of applied PEEP (17.9 vs. 10.8 cm H₂O on day 2 of ECMO), decreased incidence of hemodynamically significant RV dysfunction (4.55% vs. 44.0%, p = 0.0001), and higher survival to decannulation (72.7% vs. 44.0%, p = 0.022). Survival to discharge did not reach statistical significance (27% vs. 11%, p = 0.211). In univariate logistic regression analysis, optimal PEEP was associated with less hemodynamically significant RV dysfunction with an odds ratio (OR) of 0.06 (95% confidence interval [CI] = 0.01-0.27, p = 0.0008) and increased survival to decannulation with an OR of 3.39 (95% CI 1.23-9.79), p = 0.02), though other confounding factors may have contributed.

Extracorporeal membrane oxygenation (ECMO) and beyond in near fatal asthma: A comprehensive review

The treatment of choice in severe asthma exacerbations with respiratory failure includes ventilatory support, both invasive and/or non-invasive, along with different kinds of asthma medication. Of note, the rate of mortality of patients with asthma has decreased substantially in recent years mainly due to significant advances in pharmacological treatment and other management strategies. However, the risk of death in patients with severe asthma who require invasive mechanical ventilation has been estimated between 6.5% and 10.3%. When conventional measures fail, rescue strategies, such as extracorporeal membrane oxygenation (ECMO) or extracorporeal CO2 removal (ECCO2R) may need to be implemented. While ECMO does not constitute a definitive treatment per se, it can minimize further ventilator associated lung injury (VALI) and can enable diagnostic-therapeutic maneuvers that cannot be performed without ECMO such as bronchoscopy and transfer for diagnostic imaging. Asthma is one of the diseases that is associated with excellent outcomes for patients with refractory respiratory failure requiring ECMO support, as shown by the Extracorporeal Life Support Organization (ELSO) registry. Moreover, in such situations, the use of ECCO2R for rescue has been described and utilized in both children and adults and is more widely spread in different hospitals than ECMO. In this article, we aim to review the evidence for the usefulness of extracorporeal respiratory support measures in the management of severe asthma exacerbations that lead to respiratory failure.

Association Between Mortality and Ventilator Parameters in Children With Respiratory Failure on ECMO

BACKGROUND

In refractory respiratory failure, extracorporeal membrane oxygenation (ECMO) is a rescue therapy to prevent ventilator-induced lung injury. Optimal ventilator parameters during ECMO remain unknown. Our objective was to describe the association between mortality and ventilator parameters during ECMO for neonatal and pediatric respiratory failure.

METHODS

We performed a secondary analysis of the Bleeding and Thrombosis on ECMO dataset. Ventilator parameters included breathing frequency, tidal volume, peak inspiratory pressure, PEEP, dynamic driving pressure, pressure support, mean airway pressure, and FIO2 . Parameters were evaluated before cannulation, on the calendar day of ECMO initiation (ECMO day 1), and the day before ECMO separation.

RESULTS

Of 237 included subjects analyzed, 64% were neonates, of whom 36% had a congenital diaphragmatic hernia. Of all the subjects, 67% were supported on venoarterial ECMO. Overall in-hospital mortality was 35% (n = 83). The median (interquartile range) PEEP on ECMO day 1 was 8 (5.0-10.0) cm H2O for neonates and 10 (8.0-10.0) cm H2O for pediatric subjects. By multivariable analysis, higher PEEP on ECMO day 1 in neonates was associated with lower odds of in-hospital mortality (odds ratio 0.77, 95% CI 0.62-0.92; P = .01), with a further amplified effect in neonates with congenital diaphragmatic hernia (odds ratio 0.59, 95% CI 0.41-0.86; P = .005). No ventilator type or parameter was associated with mortality in pediatric subjects.

CONCLUSIONS

Avoiding low PEEP on ECMO day 1 for neonates on ECMO may be beneficial, particularly those with a congenital diaphragmatic hernia. No additional ventilator parameters were associated with mortality in either neonatal or pediatric subjects. PEEP is a modifiable parameter that may improve neonatal survival during ECMO and requires further investigation.

Long-Term Follow-Up of Patients Needing Extracorporeal Membrane Oxygenation Following a Critical Course of COVID-19

INTRODUCTION

Severe respiratory failure is one of the most serious complications of coronavirus disease 2019 (COVID-19). In a small proportion of patients, mechanical ventilation fails to provide adequate oxygenation and extracorporeal membrane oxygenation (ECMO) is needed. The surviving individuals need long-term follow-up as it is not clear what their prognosis is.

AIM

To provide a complex clinical picture of patients during follow-up exceeding one year after the ECMO therapy due to severe COVID-19.

METHODS

All subjects involved in the study required ECMO in the acute stage of COVID-19. The survivors were followed-up for over one year at a specialized respiratory medical center.

RESULTS

Of the 41 patients indicated for ECMO, 17 patients (64.7% males) survived. The average age of survivors was 47.8 years, and the average BMI was 34.7 kg·m^-2. The duration of ECMO support was 9.4 days. A mild decrease in vital capacity (VC) and transfer factor (DLCO) was observed on the initial follow-up visit (82.1% and 60%, respectively). VC improved by 6.2% and by an additional 7.5% after 6 months and 1 year, respectively. DLCO improved by 21.1% after 6 months and remained stable after 1 year. Post-intensive care consequences included psychological problems and neurological impairment in 29% of patients; 64.7% of the survivors got vaccinated against SARS-CoV-2 within 12 months of hospitalization and 17.6% experienced reinfection with a mild course.

CONCLUSION

The COVID-19 pandemic has significantly increased the need for ECMO. Patients' quality of life after ECMO is temporarily significantly reduced but most patients do not experience permanent disability.

Mechanical power of ventilation and driving pressure: two undervalued parameters for pre extracorporeal membrane oxygenation ventilation and during daily management?

The current ARDS guidelines highly recommend lung protective ventilation which include plateau pressure (P_plat < 30 cm H₂O), positive end expiratory pressure (PEEP > 5 cm H₂O) and tidal volume (V_t of 6 ml/kg) of predicted body weight. In contrast, the ELSO guidelines suggest the evaluation of an indication of veno-venous extracorporeal membrane oxygenation (ECMO) due to hypoxemic or hypercapnic respiratory failure or as bridge to lung transplantation. Finally, these recommendations remain a wide range of scope of interpretation. However, particularly patients with moderate-severe to severe ARDS might benefit from strict adherence to lung protective ventilation strategies. Subsequently, we discuss whether extended physiological ventilation parameter analysis might be relevant for indication of ECMO support and can be implemented during the daily routine evaluation of ARDS patients. Particularly, this viewpoint focus on driving pressure and mechanical power.

Research progress of portable extracorporeal membrane oxygenation

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is primarily used for the supportive treatment of patients suffering from severe cardiopulmonary failure. With the continued development of ECMO technology, the relevant scenarios also extend pre-hospital and inter-hospital. In order to meet the needs of emergency treatment in communities, disaster sites and battlefields, inter-hospital transfer and evacuation; miniaturized and portable ECMO has become a current research hotspot.

AREA COVERED

The paper first introduces the principle, composition and common modes of ECMO and summarizes the research status of portable ECMO, Novalung and wearable ECMO, analyzes the characteristics and shortcomings of existing equipment. finally, we discussed the focus and development trend of portable ECMO technology.

EXPERT OPINION

Currently, portable ECMO has many applications in interhospital transport and there are various studies on portable and wearable ECMO devices, but the development of portable ECMO still faces many challenges. In the future, research related to integrated components, rich sensor arrays, Intelligent ECMO system and lightweight technology can make future portable ECMO more suitable for pre-hospital emergency and interhospital transport.

Awake Fiberoptic Nasotracheal Intubation and Anesthetic Management of a Patient With a Compressed and Deviated Airway From a Massive Thyroid Goiter: A Case Report

Difficult airway management is a challenge for anesthesiologists, requiring proper assessment, planning, and sometimes a multidisciplinary approach to establish a secure airway. Here we present a case where the patient had a large thyroid goiter with significant tracheal compression. Due to the large size of the thyroid mass and the location of tracheal narrowing, fiberoptic intubation appeared to be challenging, and a surgical airway was not a viable option to obtain a secure airway for a total thyroidectomy. This case report discusses awake fiberoptic intubation and intraoperative anesthetic management of a patient with known airway compression and explores the alternative method for obtaining a definitive airway through venovenous extracorporeal membrane oxygenation.

Extracorporeal Membrane Oxygenation in Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

To systematically review and assimilate literature on children receiving extracorporeal membrane oxygenation (ECMO) support in pediatric acute respiratory distress syndrome (PARDS) with the goal of developing an update to the Pediatric Acute Lung Injury Consensus Conference recommendations and statements about clinical practice and research.

DATA SOURCES

Electronic searches of MEDLINE (Ovid), Embase (Elsevier), and CINAHL Complete (EBSCOhost).

STUDY SELECTION

The search used a medical subject heading terms and text words to capture studies of ECMO in PARDS or acute respiratory failure. Studies using animal models and case reports were excluded from our review.

DATA EXTRACTION

Title/abstract review, full-text review, and data extraction using a standardized data collection form.

DATA SYNTHESIS

The Grading of Recommendations Assessment, Development, and Evaluation approach was used to identify and summarize evidence and develop recommendations. There were 18 studies identified for full-text extraction. When pediatric data was lacking, adult and neonatal data from randomized clinical trials and observational studies were considered. Six clinical recommendations were generated related to ECMO indications, initiation, and management in PARDS. There were three good practice statements generated related to ECMO indications, initiation, and follow-up in PARDS. Two policy statements were generated involving the impact of ECMO team organization and training in PARDS. Last, there was one research statement.

CONCLUSIONS

Based on a systematic literature review, we propose clinical management, good practice and policy statements within the domains of ECMO indications, initiation, team organization, team training, management, and follow-up as they relate to PARDS.

Neurological monitoring in ECMO patients: current state of practice, challenges and lessons

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) in critically ill patients serves as a management option for end-stage cardiorespiratory failure in medical and surgical conditions. Patients on ECMO are at a high risk of neurologic adverse events including intracranial hemorrhage (ICH), acute ischemic stroke (AIS), seizures, diffuse cerebral edema, and hypoxic brain injury. Standard approaches to neurological monitoring for patients receiving ECMO support can be challenging for multiple reasons, including the severity of critical illness, deep sedation, and/or paralysis. This narrative literature review provides an overview of the current landscape for neurological monitoring in this population.

METHODS

A literature search using PubMed was used to aid the understanding of the landscape of published literature in the area of neurological monitoring in ECMO patients.

RESULTS

Review articles, cohort studies, case series, and individual reports were identified. A total of 73 varied manuscripts were summarized and included in this review which presents the challenges and strategies for performing neurological monitoring in this population.

CONCLUSION

Neurological monitoring in ECMO is an area of interest to many clinicians, however, the literature is limited, heterogenous, and lacks consensus on the best monitoring practices. The evidence for optimal neurological monitoring that could impact clinical decisions and functional outcomes is lacking. Additional studies are needed to identify effective measures of neurological monitoring while on ECMO.

Emerging concepts in heart failure management and treatment: circulatory support with extracorporeal membrane oxygenation (ECMO)

Circulatory support with extracorporeal membrane oxygenation (ECMO) is being increasingly used in several critical situations but evidence of its impact on outcomes is inconsistent. Understanding of the specific indications and appropriate timing of implantation of this technology might lead to improved results. Indeed, the line between success and futility may be sometimes very thin when facing a patient in critical condition. New techniques with lighter, simpler and effective devices are being developed. Hence, ECMO has become an accessible technology that is being increasingly used outside of the operating room by heart failure specialists, critical care cardiologists and intensivists. Proper timing of utilization and choice of device may lead to better outcomes. We herein aim to improve this knowledge gap by conducting a literature review to provide simple information, evidence-based indications and a practical approach for cardiologists who may encounter acutely ill adult patients that may be ECMO candidates. This article is part of the Emerging concepts in heart failure management and treatment Special Issue: https://www.drugsincontext.com/special_issues/emerging-concepts-in-heart-failure-management-and-treatment.

Perioperative extracorporeal membrane oxygenation in pediatric congenital heart disease: Chinese expert consensus

BACKGROUND

Congenital heart disease (CHD) is one of the main supportive diseases of extracorporeal membrane oxygenation in children. The management of extracorporeal membrane oxygenation (ECMO) for pediatric CHD faces more severe challenges due to the complex anatomical structure of the heart, special pathophysiology, perioperative complications and various concomitant malformations. The survival rate of ECMO for CHD was significantly lower than other classifications of diseases according to the Extracorporeal Life Support Organization database. This expert consensus aims to improve the survival rate and reduce the morbidity of this patient population by standardizing the clinical strategy.

METHODS

The editing group of this consensus gathered 11 well-known experts in pediatric cardiac surgery and ECMO field in China to develop clinical recommendations formulated on the basis of existing evidences and expert opinions.

RESULTS

The primary concern of ECMO management in the perioperative period of CHD are patient selection, cannulation strategy, pump flow/ventilator parameters/vasoactive drug dosage setting, anticoagulation management, residual lesion screening, fluid and wound management and weaning or transition strategy. Prevention and treatment of complications of bleeding, thromboembolism and brain injury are emphatically discussed here. Special conditions of ECMO management related to the cardiovascular anatomy, haemodynamics and the surgical procedures of common complex CHD should be considered.

CONCLUSIONS

The consensus could provide a reference for patient selection, management and risk identification of perioperative ECMO in children with CHD. Video abstract (MP4 104726 kb).

Transesophageal Echocardiography-Guided Extracorporeal Membrane Oxygenation Cannulation in COVID-19 Patients

OBJECTIVES

A paucity of data supports the use of transesophageal echocardiography (TEE) for bedside extracorporeal membrane oxygenation (ECMO) cannulation. Concerns have been raised about performing TEEs in patients with COVID-19. The authors describe the use and safety of TEE guidance for ECMO cannulation for COVID-19.

DESIGN

Single-center retrospective cohort study.

SETTING

The study took place in the intensive care unit of an academic tertiary center.

PARTICIPANTS

The authors included 107 patients with confirmed SARS-CoV-2 infection who underwent bedside venovenous ECMO (VV ECMO) cannulation under TEE guidance between May 2020 and June 2021.

INTERVENTIONS

TEE-guided bedside VV ECMO cannulation.

MEASUREMENTS

Patient characteristics, physiologic and ventilatory parameters, and echocardiographic findings were analyzed. The primary outcome was the number of successful TEE-guided bedside cannulations without complications. The secondary outcomes were cannulation complications, frequency of cannula repositioning, and TEE-related complications.

MAIN RESULTS

TEE-guided cannulation was successful in 99% of the patients. Initial cannula position was adequate in all but 1 patient. Fourteen patients (13%) required cannula repositioning during ECMO support. Forty-five patients (42%) had right ventricular systolic dysfunction, and 9 (8%) had left ventricular systolic dysfunction. Twelve patients (11%) had intracardiac thrombi. One superficial arterial injury and 1 pneumothorax occurred. No pericardial tamponade, hemothorax or intraabdominal bleeding occurred in the authors' cohort. No TEE-related complications or COVID-19 infection of healthcare providers were reported during this study.

CONCLUSIONS

Bedside TEE guidance for VV ECMO cannulation is safe in patients with severe respiratory failure due to COVID-19. No tamponade or hemothorax, nor TEE-related complications were observed in the authors' cohort.

Multi-Lobar Atelectasis in Children Receiving Venoarterial Extracorporeal Membrane Oxygenation for Cardiac Indications

BACKGROUND

Respiratory complications are common in patients who require venoarterial (VA) extracorporeal membrane oxygenation (ECMO) for cardiac indications. We aimed to examine the frequency and characteristics of patients who develop multi-lobar atelectasis early in the course of VA ECMO and to identify factors associated with its occurrence.

METHODS

We performed a single-center retrospective review of consecutive pediatric subjects on VA ECMO in the cardiovascular ICU from 2014 to 2019. Chest radiographs before VA ECMO initiation and daily for up to 5 d of VA ECMO support were reviewed. Multi-lobar atelectasis was defined as the collapse of ≥2 lobes of the same lung. Patients with multi-lobar atelectasis before or immediately after VA ECMO cannulation were excluded. Bivariate comparisons and multivariable logistic regression analyses were performed to identify factors independently associated with lung collapse. Results of the multivariable analysis are provided as odds ratio (OR) with 95% CI.

RESULTS

We reviewed 119 VA ECMO runs in 101 unique subjects. Multi-lobar atelectasis occurred in 36 runs (30%), with an isolated collapse of the left lung occurring most frequently (no. runs = 20). VA ECMO runs complicated by multi-lobar atelectasis were significantly longer and associated with lower hospital survival (51% vs 77%, survival in subjects without multi-lobar atelectasis; P = .01). Multivariable logistic regression analysis identified a subsequent ECMO run during the same admission to be independently associated with multi-lobar atelectasis (OR 5.4, 95% CI 1.2-21.5). Subanalysis of the subjects with isolated left lung collapse revealed male sex (OR 8.9, 95% CI 1.6-48.2) and subsequent ECMO run during the same admission (OR 4.0, 95% CI 1.2-13.6) to be independently associated with this complication, and mechanical ventilation at least 12 h before ECMO may be protective (OR 0.22, 95% CI 0.07-0.76).

CONCLUSIONS

Multi-lobar atelectasis commonly occurred in children who were receiving VA ECMO for cardiac failure and was associated with worse outcomes. Male patients, a subsequent VA ECMO run during the same hospitalization, and patients in whom mechanical ventilation was initiated shortly before ECMO cannulation may be at increased risk for this complication.

Comparison of Hemostatic Changes in Pump-driven Extracorporeal Carbon Dioxide Removal and Venovenous Extracorporeal Membrane Oxygenation

Extracorporeal carbon dioxide removal (ECCO 2 R) has gained widespread use as a supposedly less invasive alternative for hypercapnic respiratory failure besides venovenous extracorporeal membrane oxygenation (VV ECMO). Despite technological advances, coagulation-related adverse events remain a major challenge in both therapies. The overlapping operating areas of VV ECMO and pump-driven ECCO 2 R could allow for a device selection targeted at the lowest risk of such complications. This retrospective analysis of 47 consecutive patients compared hemostatic changes between pump-driven ECCO 2 R (n = 23) and VV ECMO (n = 24) by application of linear mixed effect models. A significant decrease in platelet count, increase in D-dimer levels, and decrease of fibrinogen levels were observed. However, except for fibrinogen, the type of extracorporeal support did not have a significant effect on the time course of these parameters. Our findings suggest that in terms of hemocompatibility, pump-driven ECCO 2 R is not significantly different from VV ECMO.

Successful lung-protective ventilatory management during the VV-ECMO in a severe COVID-19 pneumonia patient with extensive pneumomediastinum and subcutaneous emphysema: a case report

Background

Ventilatory management of respiratory failure with pneumomediastinum/subcutaneous emphysema is not established. Herein, we report a case of severe COVID-19 pneumonia with extensive pneumomediastinum/subcutaneous emphysema, rescued by thorough lung-protective ventilatory management after applying the VV-ECMO.

Case presentation

A 68-year-old male with no medical history was admitted to a local hospital and diagnosed with COVID-19 pneumonia. His pulmonary parameters worsened during invasive ventilation due to the development of pneumomediastinum/subcutaneous emphysema, and then he was transferred to our hospital. On arrival, we immediately decided to apply VV-ECMO and switch to ultraprotective ventilation. After maintaining the initial ventilation with a neuromuscular blocking agent for 2 days, we gradually increased PEEP while limiting PIP to 25 cmH₂O. The patient was weaned off VV-ECMO on day 10; he was transferred to the medical ward after extubation.

Conclusions

Lung-protective ventilatory management should be performed thoroughly during VV-ECMO in severe COVID-19 pneumonia with pneumomediastinum/subcutaneous emphysema.

Extracorporeal Life Support for Cardiac Arrest and Cardiogenic Shock

The rising incidence and recognition of cardiogenic shock has led to an increase in the use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). As clinical experience with this therapy has increased, there has also been a rapid growth in the body of observational and randomized data describing the clinical and logistical considerations required to institute a VA-ECMO program with successful clinical outcomes. The aim of this review is to summarize this contemporary data in the context of four key themes that pertain to VA-ECMO programs: the principles of patient selection; basic hemodynamic and technical principles underlying VA-ECMO; contraindications to VA-ECMO therapy; and common complications and intensive care considerations that are encountered in the setting of VA-ECMO therapy.

Mechanical Ventilation during Extracorporeal Membrane Oxygenation in Acute Respiratory Distress Syndrome: A Narrative Review

Acute respiratory distress syndrome (ARDS) is a life-threatening condition involving acute hypoxemic respiratory failure. Mechanical ventilation remains the cornerstone of management for ARDS; however, potentially injurious mechanical forces introduce the risk of ventilator-induced lung injury, multiple organ failure, and death. Extracorporeal membrane oxygenation (ECMO) is a salvage therapy aimed at ensuring adequate gas exchange for patients suffering from severe ARDS with profound hypoxemia where conventional mechanical ventilation has failed. ECMO allows for lower tidal volumes and airway pressures, which can reduce the risk of further lung injury, and allow the lungs to rest. However, the collateral effect of ECMO should be considered. Recent studies have reported correlations between mechanical ventilator settings during ECMO and mortality. In many cases, mechanical ventilation settings should be tailored to the individual; however, researchers have yet to establish optimal ventilator settings or determine the degree to which ventilation load can be decreased. This paper presents an overview of previous studies and clinical trials pertaining to the management of mechanical ventilation during ECMO for patients with severe ARDS, with a focus on clinical findings, suggestions, protocols, guidelines, and expert opinions. We also identified a number of issues that have yet to be adequately addressed.

A Case Report of Combat Blast Injury Requiring Combat Casualty Care, Far-Forward ECMO, Air Transport, and All Levels of Military Critical Care

We describe a 34-year-old soldier who sustained a blast injury in Syria resulting in tracheal 5 cm tracheal loss, cervical spine and cord injury with tetraplegia, multiple bilateral rib fractures, esophageal injury, traumatic brain injury, globe evisceration, and multiple extremity soft tissue and musculoskeletal injuries including a left tibia fracture with compartment syndrome. An emergent intubation of the transected trachea was performed in the field, and the patient was resuscitated with whole blood prehospital. During transport to the Role 2, the patient required cardiopulmonary resuscitation for cardiac arrest. On arrival, he underwent a resuscitative thoracotomy and received a massive transfusion exclusively with whole blood. A specialized critical care team transported the patient to the Role 3 hospital in Baghdad, and the DoD extracorporeal membrane oxygenation (ECMO) team was activated secondary to his unstable airway and severe hypoxia secondary to pulmonary blast injury. The casualty was cannulated in Baghdad approximately 40 hours after injury with bifemoral cannulae in a venovenous configuration. He was transported from Iraq to the U.S. Army Institute of Surgical Research Burn Center in San Antonio without issue. Extracorporeal membrane oxygenation support was successfully weaned, and he was decannulated on ECMO day 4. The early and en route use of venovenous ECMO allowed for maintenance of respiratory support during transport and bridge to operative management and demonstrates the feasibility of prolonged ECMO transport in critically ill combat casualties.

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.

Liberation From Venoarterial Extracorporeal Membrane Oxygenation: A Review

Venoarterial extracorporeal membrane oxygenation may be used for circulatory support in cardiogenic shock as a bridge to recovery, a bridge to a ventricular assist device (VAD), or a bridge to transplant. While the determination of potential exit strategies is essential before cannulation, the final determination of a patient's options may change, in part, through their in-hospital clinical course. We propose that liberation from venoarterial extracorporeal membrane oxygenation should be conceptualized as a process of discovery in the assessment of a patient's underlying clinical status and a key driver of further clinical decision-making. A trial of liberation from support should be considered when the goals of the weaning trial are well-defined and, ideally, in the absence of potentially confounding clinical factors. In this review, we will discuss readiness to wean criteria from venoarterial extracorporeal membrane oxygenation, as well as specific clinical, biochemical, and echocardiographic parameters that may prove useful in determining weaning timing and revealing the patient's underlying hemodynamic status and prognosis. The role of various cannula configurations, support devices, and pharmacological adjuncts will also be discussed. Finally, we highlight current gaps in evidence and suggest areas of future research.

Cardiac intensive care management of high-risk percutaneous coronary intervention using the venoarterial ECMO support

The emerging concept of high-risk percutaneous coronary intervention (HR-PCI) has required the adoption of a multidisciplinary team approach. Venoarterial ECMO (VA-ECMO) has been introduced as a temporary mechanical circulatory support (MCS) for HR-PCI patients in order to provide an adequate systemic perfusion during the procedure. Both patient's complexity and technological evolutions have catalyzed the development of critical care cardiology; however, ECMO therapy faces several challenges. Indeed, the management of patients on ECMO remains complex; moreover, the lack of specific recommendation for HR-PCI patients further complicates the management of these patients. In this narrative review, we give a reappraisal for the management of HR-PCI patients supported with VA-ECMO according to the available data published in current literature.

Analysis of the 2020 EACTS/ELSO/STS/AATS Expert Guidelines on the Management of Adult Postcardiotomy Extracorporeal Life Support

Extracorporeal life support (ECLS), also known as extracorporeal membrane oxygenation (ECMO), increasingly is used in postcardiotomy (PC) shock to facilitate a bridge to sustained recovery, long-term mechanical support, or heart transplantation. Given increasing prevalence and complexity of PC-ECLS, a joint expert consensus guideline was created in 2020 for management of adult PC-ECLS by the European Association for Cardio-Thoracic Surgery (EACTS), the Extracorporeal Life Support Organization (ELSO), the Society of Thoracic Surgeons (STS), and the American Association of Thoracic Surgery (AATS). The aim of this analysis was to comprehensively review the expert consensus guidelines, with particular emphasis on PC-ECLS candidacy, timing, cannula configuration, left ventricular distention, anticoagulation, ECLS weaning, and intensive care unit complications. This analysis finds the expert consensus guideline to be timely, pertinent, and clinically valuable, although there remains the need for larger clinical trials to codify best practices.

Respiratory care for the critical patients with 2019 novel coronavirus

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted through respiratory droplets, aerosols and close contact. Cross infections occur because viruses spread rapidly among humans. Nineteen percent (19%) of the infected patients developed severe pneumonia and acute respiratory distress syndrome (ARDS). Hypoxemia usually occurs and patients may require oxygen therapy or mechanical ventilation (MV) support. In this article, recently published clinical experience and observational studies were reviewed. Corresponding respiratory therapy regarding different stages of infection is proposed. Infection control principles and respiratory strategies including oxygen therapy, non-invasive respiratory support (NIRS), intubation evaluation, equipment preparation, ventilator settings, special maneuvers comprise of the prone position (PP), recruitment maneuver (RM), extracorporeal membrane oxygenation (ECMO), weaning and extubation are summarized. Respiratory equipment and device disinfection recommendations are worked up. We expect this review article could be used as a reference by healthcare workers in patient care while minimizing the risk of environmental contamination.

Novel strategy for improved outcomes of extra-corporeal membrane oxygenation as a treatment for refractory post cardiotomy cardiogenic shock in the current era: a refreshing new perspective

OBJECTIVES

Post-cardiotomy cardiogenic shock is an infrequent but important cause of death following cardiac surgery. Extra-corporeal membrane oxygenation offers the opportunity for temporary cardiovascular support and myocardial rest, with a view to recovery. We examine our results with our recently-implemented management algorithm.

METHODS

We report our series of 15 consecutive patients out of 357 patients [4.2%] who required institution of veno-arterial extra-corporeal membrane oxygenation system support as treatment for Post-cardiotomy cardiogenic shock in the current era [January-2017 to January-2020].

RESULTS

The mean age was 64.3 ± 11.6 years (range: 40-82 years); there were 13 males (86.7%). Duration of veno-arterial extra-corporeal membrane oxygenation support was 6.7 ± 1.9 days. Duration of stay on intensive care unit [ICU] was 18.9 ± 17.1 days. Duration of hospital-stay was 28.3 ± 20.8 days. Survival to discharge and at 2.2 ± 0.9 years was 67%.

CONCLUSIONS

We have shown clearly that veno-arterial extra-corporeal membrane oxygenation is an important rescue option for patients who develop refractory post-cardiotomy cardiogenic shock, with improved survival of 67% at 2.2 ± 0.9 years in those placed on post-cardiotomy veno-arterial extra corporeal membrane oxygenation support, which is superior to that reported hitherto in literature. We have sought to highlight the successes of post cardiotomy veno-arterial extra corporeal membrane oxygenation support, with improved results, based on careful patient selection, as well as diligent management of these critically-ill patients in the postoperative period, prior to establishment of irreversible end-organ dysfunction. Our strategy has also helped us rationalize and optimize the use of this expensive treatment modality.

Mechanical Ventilation Strategy Guided by Transpulmonary Pressure in Severe Acute Respiratory Distress Syndrome Treated With Venovenous Extracorporeal Membrane Oxygenation

OBJECTIVES

Previous studies have suggested that adjusting ventilator settings based on transpulmonary pressure measurements may minimize ventilator-induced lung injury, but this has never been investigated in patients with severe acute respiratory distress syndrome supported with venovenous extracorporeal membrane oxygenation. We aimed to evaluate whether a transpulmonary pressure-guided ventilation strategy would increase the proportion of patients successfully weaned from venovenous extracorporeal membrane oxygenation support in patients with severe acute respiratory distress syndrome.

DESIGN

Single-center, prospective, randomized controlled trial.

SETTING

Sixteen-bed, respiratory ICU at a tertiary academic medical center.

PATIENTS

Severe acute respiratory distress syndrome patients receiving venovenous extracorporeal membrane oxygenation.

INTERVENTIONS

One-hundred four patients were randomized to transpulmonary pressure-guided ventilation group (n = 52) or lung rest strategy group (n = 52) groups. Two patients had cardiac arrest during establishment of venovenous extracorporeal membrane oxygenation in the lung rest group did not receive the assigned intervention. Thus, 102 patients were included in the analysis.

MEASUREMENTS AND MAIN RESULTS

The proportion of patients successfully weaned from venovenous extracorporeal membrane oxygenation in the transpulmonary pressure-guided group was significantly higher than that in the lung rest group (71.2% vs 48.0%; p = 0.017). Compared with the lung rest group, driving pressure, tidal volumes, and mechanical power were significantly lower, and positive end-expiratory pressure was significantly higher, in the transpulmonary pressure-guided group during venovenous extracorporeal membrane oxygenation support. In the transpulmonary pressure-guided group, levels of interleukin-1β, interleukin-6, and interleukin-8 were significantly lower, and interleukin-10 was significantly higher, than those of the lung rest group over time. Lung density was significantly lower in the transpulmonary pressure-guided group after venovenous extracorporeal membrane oxygenation support than in the lung rest group.

CONCLUSIONS

A transpulmonary pressure-guided ventilation strategy could increase the proportion of patients with severe acute respiratory distress syndrome successfully weaned from venovenous extracorporeal membrane oxygenation.

Prevention and treatment of pulmonary congestion in patients undergoing venoarterial extracorporeal membrane oxygenation for cardiogenic shock

Cardiogenic shock is still a major driver of mortality on intensive care units and complicates ∼10% of acute coronary syndromes with contemporary mortality rates up to 50%. In the meantime, percutaneous circulatory support devices, in particular venoarterial extracorporeal membrane oxygenation (VA-ECMO), have emerged as an established salvage intervention for patients in cardiogenic shock. Venoarterial extracorporeal membrane oxygenation provides temporary circulatory support until other treatments are effective and enables recovery or serves as a bridge to ventricular assist devices, heart transplantation, or decision-making. In this critical care perspective, we provide a concise overview of VA-ECMO utilization in cardiogenic shock, considering rationale, critical care management, as well as weaning aspects. We supplement previous literature by focusing on therapeutic issues related to the vicious circle of retrograde aortic VA-ECMO flow, increased left ventricular (LV) afterload, insufficient LV unloading, and severe pulmonary congestion limiting prognosis in a relevant proportion of patients receiving VA-ECMO treatment. We will outline different modifications in percutaneous mechanical circulatory support to meet this challenge. Besides a strategy of running ECMO at lowest possible flow rates, novel therapeutic options including the combination of VA-ECMO with percutaneous microaxial pumps or implementation of a venoarteriovenous-ECMO configuration based on an additional venous cannula supplying towards pulmonary circulation are most promising among LV unloading and venting strategies. The latter may even combine the advantages of venovenous and venoarterial ECMO therapy, providing potent respiratory and circulatory support at the same time. However, whether VA-ECMO can reduce mortality has to be evaluated in the urgently needed, ongoing prospective randomized studies EURO-SHOCK (NCT03813134), ANCHOR (NCT04184635), and ECLS-SHOCK (NCT03637205). These studies will provide the opportunity to investigate indication, mode, and effect of LV unloading in dedicated sub-analyses. In future, the Heart Teams should aim at conducting a dedicated randomized trial comparing VA-ECMO support with vs. without LV unloading strategies in patients with cardiogenic shock.

New challenges in cardiac intensive care units

Critical care cardiology is a steadily and rapidly developing sub-specialization within cardiovascular medicine, since the first emergence of a coronary care unit in the early 1960s. Today, modern cardiac intensive care units (CICU) serve a complex patient population with a high burden of cardiovascular and non-cardiovascular critical illnesses. Treatment of these patients requires a multidisciplinary approach, with a combination of highly specialized knowledge and skills in cardiovascular diseases, as well as emergency, critical-care and internal medicine. The CICU has always posed special challenges to both experienced intensivists as well as fellows-in-training (FIT) and is certainly one of the most demanding training phases. In recent years, these challenges have grown significantly owing to technological innovations, with new and steadily rising numbers of complex interventional procedures and new options for temporary circulatory support for critically ill patients, such as venoarterial extracorporeal membrane oxygenation (VA-ECMO). Herein, we focus on the successful CICU management of these special patient cohorts, which must become an integral part of critical-care training.

Bridging With Extracorporeal Membrane Oxygenation Under the New Heart Allocation System: A United Network for Organ Sharing Database Analysis

BACKGROUND

The effect of the new donor heart allocation system on survival following bridging to transplantation with venous-arterial extracorporeal membrane oxygenation remains unknown. The new allocation system places extracorporeal membrane oxygenation-supported candidates at the highest status.

METHODS

The United Network for Organ Sharing database was queried for adults bridged to single-organ heart transplantation with extracorporeal membrane oxygenation from October 2006 to February 2020. Association between implementation of the new system and recipient survival was analyzed using Kaplan-Meier estimates, Cox proportional hazards models, and propensity score matching.

RESULTS

Of 364 recipients included, 173 and 191 were transplanted under new and old systems, respectively. Compared with the old system, waitlist time was halved under the new system (5 versus 10 days, P<0.01); recipients also demonstrated lower rates of prior cardiac surgery (32.9% versus 44.5%, P=0.03) and preoperative ventilation (30.6% versus 42.4%, P=0.02). Unadjusted 180-day survival was 90.2% (95% CI, 84.7%-94.2%) and 69.6% (95% CI, 62.6%-76.1%) under the new and old systems, respectively. Cox proportional hazards analysis demonstrated listing and transplantation under the new system to be an independent predictor of post-transplant survival (adjusted hazard ratio, 0.34 [95% CI 0.20-0.59]). Propensity score matching demonstrated a similar trend (hazard ratio, 0.36 [95% CI, 0.19-0.66]). Candidates listed under the new system were significantly less likely to experience waitlist mortality or deterioration (subhazard ratio, 0.38 [95% CI, 0.25-0.58]) and more likely to survive to transplant (subhazard ratio, 4.29 [95% CI, 3.32-5.54]).

CONCLUSIONS

Recipients transplanted following extracorporeal membrane oxygenation bridging to transplantation under the new system achieve greater 180-day survival compared with the old and demonstrate less preoperative comorbidity. Waitlist outcomes have also improved significantly under the new allocation system.

A Dedicated Veno-Venous Extracorporeal Membrane Oxygenation Unit during a Respiratory Pandemic: Lessons Learned from COVID-19 Part II: Clinical Management

(1) Background: COVID-19 acute respiratory distress syndrome (CARDS) has several distinctions from traditional acute respiratory distress syndrome (ARDS); however, patients with refractory respiratory failure may still benefit from veno-venous extracorporeal membrane oxygenation (VV-ECMO) support. We report our challenges caring for CARDS patients on VV-ECMO and alterations to traditional management strategies. (2) Methods: We conducted a retrospective review of our institutional strategies for managing patients with COVID-19 who required VV-ECMO in a dedicated airlock biocontainment unit (BCU), from March to June 2020. The data collected included the time course of admission, VV-ECMO run, ventilator length, hospital length of stay, and major events related to bleeding, such as pneumothorax and tracheostomy. The dispensation of sedation agents and trial therapies were obtained from institutional pharmacy tracking. A descriptive statistical analysis was performed. (3) Results: Forty COVID-19 patients on VV-ECMO were managed in the BCU during this period, from which 21 survived to discharge and 19 died. The criteria for ECMO initiation was altered for age, body mass index, and neurologic status/cardiac arrest. All cannulations were performed with a bedside ultrasound-guided percutaneous technique. Ventilator and ECMO management were routed in an ultra-lung protective approach, though varied based on clinical setting and provider experience. There was a high incidence of pneumothorax (n = 19). Thirty patients had bedside percutaneous tracheostomy, with more procedural-related bleeding complications than expected. A higher use of sedation was noted. The timing of decannulation was also altered, given the system constraints. A variety of trial therapies were utilized, and their effectiveness is yet to be determined. (4) Conclusions: Even in a high-volume ECMO center, there are challenges in caring for an expanded capacity of patients during a viral respiratory pandemic. Though institutional resources and expertise may vary, it is paramount to proceed with insightful planning, the recognition of challenges, and the dynamic application of lessons learned when facing a surge of critically ill patients.

Favourable outcome after prolonged veno-venous extracorporeal membrane oxygenation (V-V ECMO) support for Pneumocystis jirovecii pneumonia in a renal transplant recipient

A 27-year-old man, with a history of renal transplantation, presented with acute kidney failure and Pneumocystis jirovecii pneumonia. The patient developed severe acute respiratory failure and required support by veno-venous extracorporeal membrane oxygenation for a total of 59 days. During this period, the patient had extremely low tidal volumes using a lung protective ventilation strategy and intermittent prone positioning was used to optimise oxygenation. There was full recovery of pulmonary and partial recovery of renal function.

Veno-Venous Extracorporeal Membrane Oxygenation in COVID-19-Where Are We Now?

The recent development in extracorporeal life support (ECLS) has created new therapeutic opportunities for critically ill patients. An interest in extracorporeal membrane oxygenation (ECMO), the pinnacle of ECLS techniques, has recently increased, as for the last decade, we have observed improvements in the survival of patients suffering from severe acute respiratory distress syndrome (ARDS) while on ECMO. Although there is a paucity of conclusive data from clinical research regarding extracorporeal oxygenation in COVID-19 patients, the pathophysiology of the disease makes veno-venous ECMO a promising option.

Hemolysis in patients with Extracorporeal Membrane Oxygenation therapy for severe Acute Respiratory Distress Syndrome - a systematic review of the literature

The Acute Respiratory Distress Syndrome (ARDS) is common in patients on the Intensive Care Unit and associated with significant mortality rates. In situations of severe respiratory insufficiency and failure of all possible conservative therapeutic approaches, veno-venous extracorporeal membrane oxygenation (VV ECMO) is used as a final option for temporary replacement of pulmonary function. ARDS as well as sepsis and VV ECMO treatment are all associated with intravascular hemolysis. The extent and relevance of intravascular hemolysis in the context of ARDS therapy is unclear. This systematic review aims to summarize the current evidence on the incidence and associated complications of intravascular hemolysis in adult patients with ARDS and treatment with VV ECMO. The databases MEDLINE, EMBASE and Web of Science were systematically searched and 19 publications fulfilled inclusion criteria. The incidence of hemolysis in patients with ARDS and treatment with VV ECMO ranged from 0 to 41% with survivors showing lower incidences and less severe hemolysis. A pump head thrombosis and high blood flows (≥3 l/min) as well as use of dual-lumen cannulas but not different pump models were associated with increased hemolysis. In conclusion, intravascular hemolysis in patients with ARDS and treatment with VV ECMO is a common and relevant complication that appears associated with increased mortality. Apart from ECMO hardware-settings, no additional possible causes for increased red cell breakdown such as disease severity, duration of ECMO therapy, or number and quality of red blood cell transfusions were investigated. Further research is needed to determine the origin and relevance of intravascular hemolysis in patients with ARDS and treatment with VV ECMO.

Development of a computational simulator of the extracorporeal membrane oxygenation and its validation with in vitro measurements

In the recent years, the use of extracorporeal membrane oxygenation (ECMO) has grown substantially, posing the need of having specialized medical and paramedical personnel dedicated to it. Optimization of the therapy, definition of new therapeutic strategies, and ECMO interaction with the cardiorespiratory system require numerous specific skills and preclinical models for patient successful management. The aim of the present work is to develop and validate a computational model of ECMO and connect it to an already existing lumped parameter model of the cardiorespiratory system. The ECMO model was connected between the right atrium and the aorta of the cardiorespiratory simulator. It includes a hydraulic module that is a representation of the tubing, oxygenator, and pump. The resulting pressures and flows within the ECMO circuit were compared to the measurements conducted in vitro on a real ECMO. Additionally, the hemodynamic effects the ECMO model elicited on the cardiorespiratory simulator were compared with experimental data taken from the literature. The comparison between the hydraulic module and the in vitro measurements evidenced a good agreement in terms of flow, pressure drops across the pump, across the oxygenator and the tubing (maximal percentage error recorded was 17.6%). The hemodynamic effects of the ECMO model on the cardiovascular system were in agreement with what observed experimentally in terms of cardiac output, systemic pressure, pulmonary arterial pressure, and left atrial pressure. The ECMO model we developed and embedded into the cardiorespiratory simulator, is a useful tool for the investigation of basic physiological mechanisms and principles of ECMO therapy. The model was sided by a user interface dedicated to training applications. As such, the resulting simulator can be used for the education of students, medical and paramedical personnel.

Extracorporeal membrane oxygenation for COVID-19 induced hypoxia: Single-center study

INTRODUCTION

The pandemic of the coronavirus disease 2019 (COVID-19) and associated pneumonia represent a clinical and scientific challenge. The role of Extracorporeal Membrane Oxygenation (ECMO) in such a crisis remains unclear.

METHODS

We examined COVID-19 patients who were supported for acute respiratory failure by both conventional mechanical ventilation (MV) and ECMO at a tertiary care institution in Washington DC. The study period extended from March 23 to April 29. We identified 59 patients who required invasive mechanical ventilation. Of those, 13 patients required ECMO.

RESULTS

Nine out of 13 ECMO (69.2%) patients were decannulated from ECMO. All-cause ICU mortality was comparable between both ECMO and MV groups (6 patients [46.15%] vs. 22 patients [47.82 %], p = 0.92). ECMO non-survivors vs survivors had elevated D-dimer (9.740 mcg/ml [4.84-20.00] vs. 3.800 mcg/ml [2.19-9.11], p = 0.05), LDH (1158 ± 344.5 units/L vs. 575.9 ± 124.0 units/L, p = 0.001), and troponin (0.4315 ± 0.465 ng/ml vs. 0.034 ± 0.043 ng/ml, p = 0.04). Time on MV as expected was significantly longer in ECMO groups (563.3 hours [422.1-613.9] vs. 247.9 hours [101.8-479] in MV group, p = 0.0009) as well as ICU length of stay 576.2 hours [457.5-652.8] in ECMO group vs. 322.2 hours [120.6-569.3] in MV group, p = 0.012).

CONCLUSION

ECMO is a supportive intervention for COVID-19 associated pneumonia that could be considered if the optimum mechanical ventilation is deemed ineffective. Biomarkers such as D-dimer, LDH, and troponin could help with discerning the clinical prognosis in patients with COVID-19 pneumonia.

COVID–19急性呼吸不全への人工呼吸管理とECMO管理：基本的考え方(Mechanical ventilation and extracorporeal membrane oxygenation for acute respiratory failure owing to COVID–19: basic concept)

The pillars of managing critically ill patients with acute respiratory failure owing to coronavirus disease 2019 (COVID–19) are mechanical ventilation and extracorporeal membrane lung oxygenation (ECMO) as supportive therapies for impaired respiratory function. Given the increasing number of patients with COVID–19, a summary of standardized care regarding ECMO that can serve as a reference in clinical practice is proposed as an expert consensus statement. Indications, management practices, and caveats for ECMO management are described, including those in the presence of resource constraints.