Awake veno-arterial extracorporeal membrane oxygenation in patients with perioperative period acute heart failure in cardiac surgery

ECMO for bridging lung transplantation

BACKGROUND

With the shift in donor lung allocation from blood type and waiting order to the use of the lung allocation score (LAS) system, there are increasingly more cases of ECMO bridging lung transplantation. However, there are still some problems in case selection, implementation, and management.

METHODS

We analyzed and summarized a series of data on ECMO bridging lung transplantation through an extensive literature review.

RESULTS

The improvement of the lung transplant allocation system and the progress of ECMO technology have made the ECMO bridge to lung transplant more widely used in clinical practice. The selection of bridge patients is a crucial link in the success of transplantation, and accurate assessment of the patient before transplantation is necessary. The advantages and disadvantages of different bridge strategies exist, and the appropriate bridge strategy should be selected based on the patient's situation. Bleeding and thrombosis complications often occur during ECMO circulation, and there is currently no optimal anticoagulation strategy. The predictive score for bridge post-outcome is still subject to certain limitations.

CONCLUSIONS

ECMO bridging lung transplantation is suitable for patients waiting for lung transplantation when other respiratory support is ineffective or when hemodynamic instability occurs the disease is severe and the donor organ is easily obtainable. Patients aged 65 years or older, or have reversible multiple organ dysfunction should not be included as contraindications for ECMO bridging lung transplantation.

Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) Support in New Era of Heart Transplant

Heart failure is a serious and challenging medical condition characterized by the inability of the heart to pump blood effectively, leading to reduced blood flow to organs and tissues. Several underlying causes may be linked to this, including coronary artery disease, hypertension, or previous heart attacks. Therefore, it is a chronic condition that requires ongoing management and medical attention. HF affects >64 million individuals worldwide. Heart transplantation remains the gold standard of treatment for patients with end-stage cardiomyopathy. The recruitment of marginal donors may be considered an asset at the age of cardiac donor organ shortage. Primary graft dysfunction (PGD) is becoming increasingly common in the new era of heart transplantations. PGD is the most common cause of death within 30 days of cardiac transplantation. Mechanical Circulatory Support (MCS), particularly venoarterial extracorporeal membrane oxygenation (V-A ECMO), is the only effective treatment for severe PGD. VA-ECMO support ensures organ perfusion and provides the transplanted heart with adequate rest and recovery. In the new era of heart transplantation, early use allows for increased patient survival and careful management reduces complications.

Feasibility of veno-arterial extracorporeal life support in awake patients with cardiogenic shock

OBJECTIVES

This study sought to demonstrate outcomes of veno-arterial extracorporeal life support (VA-ECLS) in non-intubated ('awake') patients with cardiogenic shock, as very few studies have investigated safety and feasibility in this population.

METHODS

This was a retrospective review of 394 consecutive VA-ECLS patients at our institution from 2017 to 2021. We excluded patients cannulated for indications definitively associated with intubation. Patients were stratified by intubation status at time of cannulation and baseline differences were balanced by inverse probability of treatment weighting. The primary outcome was in-hospital mortality while secondary outcomes included adverse events during ECLS and destination at discharge.

RESULTS

Out of 135 patients in the final cohort, 79 were intubated and 56 were awake at time of cannulation. All awake patients underwent percutaneous femoral cannulation with technical success of 100% without intubation. Indications for VA-ECLS in awake patients included acute decompensated heart failure (64.3%), pulmonary hypertension or massive pulmonary embolism (12.5%), myocarditis (8.9%) and acute myocardial infarction (5.4%). After adjustment, awake and intubated patients had similar ECLS duration (7 vs 6 days, P = 0.19), in-hospital mortality (39.6% vs 51.7%, P = 0.28), and rates of various adverse events. Intubation status was not a significant risk factor for 90-day mortality (hazard ratio [95% confidence interval]: 1.26 [0.64, 2.45], P = 0.51) in multivariable analysis. Heart transplantation (15.1% vs 4.9%) and ventricular assist device (17.4% vs 2.2%) were more common destinations at discharge in awake patients than intubated patients (P = 0.02).

CONCLUSIONS

Awake VA-ECLS is safe and feasible with comparable outcomes as intubated counterparts in select cardiogenic shock patients.

Duration of extracorporeal life support bridging delineates differences in the outcome between awake and sedated bridge-to-transplant patients

OBJECTIVES

Traditionally, patients on bridge-to-transplant extracorporeal membrane oxygenation were kept sedated and intubated. However, awake bridging strategies have evolved during recent years. This study aims to elaborate differences in physical activity and postoperative outcomes after lung transplantation, depending on bridging strategy and duration.

METHODS

Bridged patients receiving lung transplantation between 03/2013-04/2021 were analyzed. Awake bridging was defined as a Richmond Agitation-Sedation Scale score of ≥-1 until 24 h before transplantation. Patients were grouped in awake and sedated cohorts.

RESULTS

A total of 88 patients (35 awake, 53 sedated bridging) were included. After lung transplantation, mobilization to standing position was achieved earlier in awake bridged patients (7 vs 15 days, p = <0.001). Postoperative ventilation time (247 vs 88 hours, p = 0.005) and intensive care unit stay (30 vs 16 days, p = 0.004) were longer in the sedated cohort. Awake patients with bridging duration >6 days showed shorter postoperative ventilation time (108 vs 383 hours, p = 0.003), less intensive care unit days (23 vs 36, p = 0.003) and earlier mobilization to standing position (9 vs 17 days, p = <0.001). In contrast, postoperative ventilation time, and days on intensive care unit in patients with bridge-to-transplant duration ≤6 days were comparable between cohorts. Mobilization to standing position was achieved faster in the awake (≤6 days) bridged cohort (5 vs 9 days, p = 0.024).

CONCLUSIONS

Despite the complex management of bridged patients, excellent survival rates after lung transplantation can be achieved. Especially in patients with more than one week on extracorporeal membrane oxygenation, awake bridging concepts are associated with significantly faster recovery.

Awake extracorporeal life support and physiotherapy in adult patients: A systematic review of the literature

OBJECTIVE

The Awake Extracorporeal Life Support (ECLS) practice combined with physiotherapy is increasing. However, available evidence for this approach is limited, with unclear indications on timing, management, and protocols. This review summarizes available literature regarding Awake ECLS and physiotherapy application rates, practices, and outcomes in adults, providing indications for future investigations.

METHODS

Four databases were screened from inception to February 2021, for studies reporting adult Awake ECLS with/without physiotherapy. Primary outcome was hospital discharge survival, followed by Extracorporeal Membrane Oxygenation (ECMO) duration, extubation, Intensive Care Unit stay.

RESULTS

Twenty-nine observational studies and one randomized study were selected, including 1,157 patients (males n = 611/691, 88.4%) undergoing Awake ECLS. Support type was reported in 1,089 patients: Veno-Arterial ECMO (V-A = 39.6%), Veno-Venous ECMO (V-V = 56.8%), other ECLS (3.6%). Exclusive upper body cannulation and femoral cannulation were applied in 31% versus 69% reported cases (n = 931). Extubation was successful in 63.5% (n = 522/822) patients during ECLS. Physiotherapy details were given for 676 patients: exercises confined in bed for 47.9% (n = 324) patients, mobilization until standing in 9.3% (n = 63) cases, ambulation performed in 42.7% (n = 289) patients. Femoral cannulation, extubation and V-A ECMO were mostly correlated to complications. Hospital discharge survival observed in 70.8% (n = 789/1114).

CONCLUSION

Awake ECLS strategy associated with physiotherapy is performed regardless of cannulation approach. Ambulation, as main objective, is achieved in almost half the population examined. Prospective studies are needed to evaluate safety and efficacy of physiotherapy during Awake ECLS, and suitable patient selection. Guidelines are required to identify appropriate assessment/evaluation tools for Awake ECLS patients monitoring.

Impact of the inspiratory oxygen fraction on the cardiac output during jugulo-femoral venoarterial extracorporeal membrane oxygenation in the rat

Background

Venoarterial extracorporeal membrane oxygenation (V-A ECMO) with femoral access has gained wide acceptance in the treatment of critically ill patients. Since the patient´s cardiac output (CO) can compete with the retrograde aortic ECMO-flow, the aim of this study was to examine the impact of the inspiratory oxygen fraction on the cardiac function during V-A ECMO therapy.

Methods

Eighteen male Lewis rats (350–400 g) received V-A ECMO therapy. The inspiratory oxygen fraction on the ventilator was randomly set to 0.5 (group A), 0.21 (group B), or 0 in order to simulate apnea (group C), respectively. Each group consisted of six animals. Arterial blood pressure, central venous saturation (ScvO2), CO, stroke volume, left ventricular ejection fraction (LVEF), end diastolic volume, and pressure were measured. Cardiac injury was determined by analyzing the amount of lactate dehydrogenase (LDH).

Results

During anoxic ventilation the systolic, mean and diastolic arterial pressure, CO, stroke volume, LVEF and ScvO2 were significantly impaired compared to group A and B. The course of LDH values revealed no significant differences between the groups.

Conclusion

Anoxic ventilation during V-A ECMO with femoral cannulation leads to cardiogenic shock in rats. Therefore, awake V-A ECMO patients might be at risk for hypoxia-induced complications.

The Impact of Noninvasive Ventilator Assisted Ventilation Nursing Combined with Mechanical Vibration on the Level of Heart Failure Indexes in ICU Patients with Acute Heart Failure

The acute attack of acute heart failure or the continuous deterioration of cardiac function leads to a series of changes such as reduced cardiac contractility, increased cardiac load, and a sudden drop of acute cardiac output, which eventually cause pulmonary circulation congestion and acute dyspnea due to acute pulmonary congestion. To observe the impact of noninvasive ventilator-assisted ventilation nursing combined with mechanical vibration on the level of heart failure indexes in intensive care unit (ICU) patients with acute heart failure, 120 patients with acute heart failure who were treated in the ICU ward of our hospital from September 2018 to March 2021 were selected, and the qualified subjects were divided into two groups according to the 1 : 1 principle by a simple random method. 120 patients were given conventional symptomatic treatment and noninvasive ventilator-assisted ventilation. The control group received conventional nursing intervention, and the observation group was given noninvasive ventilator-assisted ventilation nursing and mechanical vibration intervention. The respiratory system indexes, heart rate, blood pressure, central venous pressure, N-terminal B-type natriuretic peptide precursor (NT-proBNP), cardiac troponin T (cTnT), and cardiac function indexes of the two groups of patients are recorded, and the prognosis of the two groups is compared. After intervention, the partial pressure of oxygen (PaO2) and blood oxygen saturation (SpO2) in the two groups were higher than those before intervention, while the partial pressure of carbon dioxide (PaCO2), respiration (RR), heart rate, blood pressure, and central venous pressure were lower than those before intervention (P < 0.05). Compared with the control group, PaO2, SpO2, systolic blood pressure, diastolic blood pressure, and central venous pressure of the observation group after intervention were significantly higher, while PaCO2, RR, and heart rate were significantly lower (P < 0.05). Compared with the control group, the LVEF of the observation group after intervention was significantly higher, while NT-proBNP, cTnT, LVESD, and LVEDD were markedly lower (P < 0.05). The ventilation time and ICU hospitalization time in the observation group were shorter than those in the control group, and the pulmonary infection rate was lower than in the control group. The remission time of infection in patients with pulmonary infection was shorter than that in the control group. When comparing the 28d mortality rate with the control group, the difference was not statistically significant (P > 0.05). Noninvasive ventilator-assisted ventilation nursing combined with mechanical vibration can improve hypoxemia symptoms and heart function, stabilize hemodynamics, shorten the course of disease and reduce the occurrence of lung infections for those patients with acute heart failure in the ICU.

Awakening in extracorporeal membrane oxygenation as a bridge to lung transplantation

Although the rate of lung transplantation (LTx), the last treatment option for end-stage lung disease, is increasing, some patients waiting for LTx need a bridging strategy for LTx due to the limited number of available donor lungs. For a long time, mechanical ventilation has been employed as a bridge to LTx because the outcome of using extracorporeal membrane oxygenation (ECMO) as a bridging strategy has been poor. However, the outcome after mechanical ventilation as a bridge to LTx was poor compared with that in patients without bridges. With advances in technology and the accumulation of experience, the outcome of ECMO as a bridge to LTx has improved, and the rate of ECMO use as a bridging strategy has increased over time. However, whether the use of ECMO as a bridge to LTx can achieve survival rates similar to those of non-bridged LTx patients remains controversial. In 2010, one center introduced awake ECMO strategy for LTx bridging, and its use as a bridge to LTx has been showing favorable outcomes to date. Awake ECMO has several advantages, such as maintenance of physical activity, spontaneous breathing, avoidance of endotracheal intubation, and reduced use of sedatives and analgesics, but it may cause serious problems. Nonetheless, several studies have shown that awake ECMO performed by a multidisciplinary team is safe. In cases where ECMO or mechanical ventilation is required due to unavoidable exacerbation in patients awaiting LTx, the application of awake ECMO performed by an appropriately trained ECMO multi-disciplinary team can be useful.

An Ovine Model of Awake Veno-Arterial Extracorporeal Membrane Oxygenation

Background: Large animal models are developed to help understand physiology and explore clinical translational significance in the continuous development of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) technology. The purpose of this study was to investigate the establishment methods and management strategies in an ovine model of VA-ECMO. Methods: Seven sheep underwent VA-ECMO support for 7 days by cannulation via the right jugular vein and artery. The animals were transferred into the monitoring cages after surgery and were kept awake after anesthesia recovery. The hydraulic parameters of ECMO, basic hemodynamics, mental state, and fed state of sheep were observed in real time. Blood gas analysis and activated clotting time (ACT) were tested every 6 h, while the complete blood count, blood chemistry, and coagulation tests were monitored every day. Sheep were euthanized after 7 days. Necropsy was performed and the main organs were removed for histopathological evaluation. Results: Five sheep survived and successfully weaned from ECMO. Two sheep died within 24-48 h of ECMO support. One animal died of fungal pneumonia caused by reflux aspiration, and the other died of hemorrhagic shock caused by bleeding at the left jugular artery cannulation site used for hemodynamic monitoring. During the experiment, the hemodynamics of the five sheep were stable. The animals stayed awake and freely ate hay and feed pellets and drank water. With no need for additional nutrition support or transfusion, the hemoglobin concentration and platelet count were in the normal reference range. The ECMO flow remained stable and the oxygenation performance of the oxygenator was satisfactory. No major adverse pathological injury occurred. Conclusions: The perioperative management strategies and animal care are the key points of the VA-ECMO model in conscious sheep. This model could be a platform for further research of disease animal models, pathophysiology exploration, and new equipment verification.

Awake venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock

BACKGROUND 

Venoarterial-extracorporeal membrane oxygenation (VA-ECMO) is currently one of the first-line therapies for refractory cardiogenic shock (CS), but its applicability is undermined by the high morbidity associated with its complications, especially those related to mechanical ventilation (MV). We aimed to assess the prognostic impact of keeping patients in refractory CS awake at cannulation and during the VA-ECMO run.

METHODS 

A 7-year database of patients given peripheral VA-ECMO support was used to conduct a propensity-score (PS)-matched analysis to balance their clinical profiles. Patients were classified as 'awake ECMO' or 'non-awake ECMO', respectively, if invasive MV was used during ≤50% or >50% of the VA-ECMO run. Primary outcomes included ventilator-associated pneumonia and ECMO-related complication rates, and secondary outcomes were 60-day and 1-year mortality. A multivariate logistic-regression analysis was used to identify whether MV at cannulation was independently associated with 60-day mortality.

RESULTS 

Among 231 patients included, 91 (39%) were 'awake' and 140 (61%) 'non-awake'. After PS-matching adjustment, the 'awake ECMO' group had significantly lower rates of pneumonia (35% vs. 59%, P = 0.017), tracheostomy, renal replacement therapy, and less antibiotic and sedative consumption. This strategy was also associated with reduced 60-day (20% vs. 41%, P = 0.018) and 1-year mortality rates (31% vs. 54%, P = 0.021) compared to the 'non-awake' group, respectively. Lastly, MV at ECMO cannulation was independently associated with 60-day mortality.

CONCLUSION 

An 'awake ECMO' management in VA-ECMO-supported CS patients is feasible, safe, and associated with improved short- and long-term outcomes.

Implementation of Venoarterial Extracorporeal Membrane Oxygenation in Nonintubated Patients

Background

Although extracorporeal membrane oxygenation (ECMO) is generally performed percutaneously, the technology is deployed under sedation and necessitates endotracheal intubation. However, in some patients, the use of venoarterial (VA) ECMO without intubation may be beneficial. Herein, we describe our experiences with VA ECMO performed without prior endotracheal intubation.

Methods

A total of 783 patients treated with VA ECMO at a single center between January 2013 and July 2018 were reviewed retrospectively. We included patients who underwent successful VA ECMO implementation without prior endotracheal intubation, and excluded those who were younger than 18 years, had ongoing cardiopulmonary resuscitation status, and had poor quality of the vessels needed for percutaneous cannulation. The primary study outcome was in-hospital survival.

Results

In total, 50 patients were included in this study, 94% of whom showed cardiogenic shock. The mean age of the study participants was 56.3±14.5 years. The median VA ECMO support time was 7 days (range, 2–13 days). Twenty-one patients (42%) did not receive ventilator care during the VA ECMO support period, while 29 patients (58%) progressed to intubation after VA ECMO implementation. The rates of survival at discharge and weaning success were 82% (n=41) and 92% (n=46), respectively, and 80% (n=40) of patients presented good Glasgow–Pittsburgh Cerebral Performance Categories scores at discharge.

Conclusion

Even in patients with cardiogenic shock, percutaneous VA ECMO can be introduced safely without prior endotracheal intubation by an experienced care team. The application of nonintubated VA ECMO might be a feasible strategy in selected cases.

Awake ECMO and mobilizing patients on ECMO

Extracorporeal membrane oxygenation (ECMO) is a lifesaving technology in critically ill patients who present with cardiac/pulmonary/combined cardiopulmonary failure. These patients are the sickest of all patients in any critical care unit and will invariably have a prolonged course and rehabilitation. Spontaneous breathing and early mobilization can reduce the intensive care unit (ICU)-acquired weakness, improve functional recovery, and reduce superadded infections and length of stay in the hospital, thus decreasing the cost of treatment. In low socioeconomic countries, there is an associated challenge of the availability of specially trained personnel necessary to manage patients on ECMO. Managing and ambulating an awake patient on ECMO is very labour-intensive and poses various challenges. Every ECMO program should aim to develop goals, methods, and protocols to this end. These can be derived from best practices worldwide by suitably adapting to available personnel and equipment. In this review, we aim to highlight the advantages and associated challenges of awake ECMO and describe protocols to aid safe ambulation and physiotherapy for ECMO patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-020-01075-z.