Venoarterial Research Articles

The Role of Echocardiography in Monitoring Patients Supported With Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is a form of critical care support for patients with severe respiratory or circulatory failure where conventional medical treatments have failed. Two main configurations of ECMO exist: Venovenous (VV) to support failing lungs, and venoarterial (VA) for circulatory shock. Echocardiography is an invaluable tool in the assessment of patients requiring ECMO. It can be utilised for decision-making regarding the most appropriate configuration, detection and management of complications, and to guide weaning. This concise review is intended to be a primer on the role of echocardiography for patients requiring ECMO for circulatory failure.

Plasmapheresis for extracorporeal membrane oxygenation (ECMO)-induced hemolysis in infants

Background: Intravascular hemolysis is a known complication of extracorporeal membrane oxygenation (ECMO). Characterized by elevated plasma-free hemoglobin (PFH), intravascular hemolysis is associated with cytotoxic effects leading to renal replacement therapy (RRT), longer ECMO runs and mortality. Therapeutic plasma exchange (TPE) in tandem with ECMO was described as a therapy for various pathologic conditions, but there are no ELSO guidelines for the treatment of ECMO-induced hemolysis. We describe the use of TPE in the management of severe ECMO-induced hemolysis. Methods: Two term neonates receiving veno-arterial (VA) ECMO developed severe PFH, with peak values over 500 mg/dL. TPE was performed in tandem with the ECMO circuit. Packed red cells were used to prime the TPE circuit, and citrate anticoagulation was added to establish the interface, which could not be achieved with existing heparin in the ECMO circuit. Therapy was completed with saline solution as a decoy for citrate, to avoid hypocalcemia and intracranial bleeding. Plasma volume was replaced by fresh frozen plasma (FFP). Results: In one patient PFH fell to 120 mg/dL, but rebounded to close to 500 mg/dL, only to stabilize between 210 and 300 mg/dL after the second TPE. He was liberated from ECMO, but could not survive a respiratory decompensation. The other patient’s PFH improved to 360 mg/dL after one TPE and continued to decline to 120 mg/dL over the ensuing days. Despite that improvement, care was withdrawn. Conclusion: TPE is effective in decreasing the burden of PFH, is well tolerated in tandem with ECMO, and a database of infants with ECMO-induced hemolysis needs to be created to assess the current practice, and establish clinical guidelines for its most appropriate therapy.

LA reservoir strain predicts elevated left atrial pressure in patients with Veno-Arterial (VA) extracorporeal membrane oxygenator (ECMO) support for cardiogenic shock

Abstract Background Veno-arterial (VA) extracorporeal membrane oxygenator (ECMO) is not a left ventricular (LV) support system as it increases aortic pressure and LV afterload due to retrograde blood flow in the aorta. This can lead to complications such as increased LV volume (LV distention), increased LV and left atrial (LA) pressures, and pulmonary edema. We sought to investigate the correlation between LA strain and invasive LA pressure (LAP) in patients with ECMO support for cardiogenic shock undergoing atrial septostomy with stenting. Methods and Results A total of 24 consecutive patients (52±20 years; 83% were male) undergoing atrial septostomy with stenting while being on ECMO support for cardiogenic shock for left heart decompression were analyzed. LAP was measured immediately after transeptal puncture and before deployment of interatrial septal stent. A comprehensive echocardiogram was performed in all patients prior to atrial septostomy. Median time difference between echocardiogram and LAP measurement was 3.5 (0.5-20) hours. LA strain analysis was performed using the TomTec Arena 2D-cardiac performance analysis (CPA) software. LA reservoir strain was measured at peak systole during the reservoir phase in a single apical 4-chamber view. Intraclass correlation coefficients between 2 different investigators were excellent (All> 0.95). Median LA reservoir strain and LAP were 3.2 (0.5-1) % and 23 (8-53) mmHg, respectively. LA reservoir strain significantly correlated with LAP (r=0.53, p=0.034). LA reservoir strain of < 1.5% can effectively predict markedly elevated LAP (LA> 30 mmHg) (OR =9.9, p =0.0016). Conclusions LA reservoir strain significantly correlated with invasive LAP. With the advent of strain imaging software, LA reservoir strain is a feasible, reproducible, noninvasive, and straightforward method to predict the need for left heart decompression and/or to guide optimal afterload management in patients with VA-ECMO for cardiogenic shock. Further a prospective simultaneous echocardiographic and invasive LAP study is needed.

Utility of venoarterial extracorporeal membrane oxygenation in patients with acute myocardial infarction complicated by cardiogenic shock

Abstract Background Acute myocardial infarction complicated by cardiogenic shock (AMI-CS) continues to portend poor clinical prognosis and remains a major cause of morbidity and mortality. Although venoarterial (VA) extracorporeal membrane oxygenation (ECMO) is frequently used in the treatment of AMI-CS, studies evaluating its benefit compared to percutaneous ventricular assist devices (pVAD) or standard medical therapy in this patient population have yielded conflicting results. Purpose The goal of this meta-analysis is to evaluate the use of ECMO compared to either pVAD or medical therapy with or without intra-aortic balloon counterpulsation (IABP) in patients presenting with AMI-CS. Methods A database search was performed for studies reporting on the association of ECMO compared to pVAD or medical therapy with or without IABP with clinical outcomes in patients with AMI-CS. The endpoints of interest were 30-day all-cause mortality and long term all-cause mortality. The databases searched included Pubmed, Web of Science, and Embase. The search was not restricted by time or publication status. Registry studies were excluded from this analysis. Results A total of 8 studies with 937 participants (447 treated with ECMO, 243 treated with pVAD, 247 treated with medical therapy with or without IABP) met inclusion criteria. Mean age was 63 years old, 80.5% were men, mean left ventricular ejection fraction was 26%, mean follow-up was 6.3 months (ranging 1-12 months). Treatment of AMI-CS patients with ECMO was not associated with lower risk of 30-day all-cause mortality compared to pVAD or standard medical therapy with or without IABP placement (OR 1.29, 95% CI 0.87-1.90; p=0.21; OR 0.58, 95% CI 0.25-1.35; p=0.13). Heterogenetic was low to moderate for each subgroup. Test for subgroup differences did not demonstrate statistically significant differences in the results for pVAD and for standard medical therapy with or without IABP (p=0.10, I2=64.1%). Compared to pVAD, ECMO was not associated lower risk of long-term mortality (OR 1.27, 95% CI 0.85-1.90; p=0.24). The heterogeneity for this analysis was low (I2=0%). Conclusion In patients presenting with AMI-CS, use of VA-ECMO is not associated with lower risk of mortality compared to pVAD or standard medical therapy with or without IABP placement. The risks and benefits of ECMO should be carefully considered compared to other forms of temporary mechanical circulatory support.Figure 1

A randomized embedded multifactorial adaptive platform for extra corporeal membrane oxygenation (REMAP ECMO) – design and rationale of the left ventricular unloading trial domain

BackgroundThe use of Extracorporeal Membrane Oxygenation (ECMO) remains associated with high rates of complications, weaning failure and mortality which can be partly explained by a knowledge gap on how to properly manage patients on ECMO support. To address relevant patient management issues, we designed a “Randomized Embedded Multifactorial Adaptive Platform (REMAP)” in the setting of ECMO (REMAP ECMO) and a first embedded randomized controlled trial (RCT) investigating the effects of routine early left ventricular (LV) unloading through intra-aortic balloon pumping (IABP). MethodsREMAP ECMO describes a registry-based platform allowing for the embedding of multiple response adaptive RCTs (trial domains) which can perpetually address the effect of relevant patient management issues on ECMO weaning success. A first trial domain studies the effects of LV unloading by means of an IABP as an adjunct to veno-arterial (V-A) ECMO versus V-A ECMO alone on ECMO weaning success at 30 days in adult cardiogenic shock patients admitted to the Intensive Care Unit (ICU). The primary outcome of this trial is “successful weaning from ECMO” being defined as a composite of survival without the need for mechanical circulatory support, heart transplantation, or left ventricular assist device (LVAD) at 30 days after initiation of ECMO. Secondary outcomes include the need for interventional escalation of LV unloading strategy, mechanistic endpoints, survival characteristics until one year after ECMO initiation, and quality of life. Trial data will be analysed using a Bayesian statistical framework. The adaptive design allows for a high degree of flexibility, such as response adaptive randomization and early stopping of the trial for efficacy or futility. The REMAP ECMO LV unloading study is approved by the Medical Ethical Committee of the Erasmus Medical Center and is publicly registered. ConclusionThis REMAP ECMO trial platform enables the efficient roll-out of multiple RCTs on relevant patient management issues. A first embedded trial domain will compare routine LV unloading by means of an IABP as an adjunct to V-A ECMO versus V-A ECMO alone. Trial registrationClinicalTrials.gov, NCT05913622

Veno-arterial extracorporeal membrane oxygenation as bridge for fluid resuscitation in a patient with acute respiratory failure and circulatory shock two years post lung transplantation.

The use of extracorporeal membrane oxygenation (ECMO) continues to evolve and is recognized as an important adjunct as a bridge to recovery or a bridge to transplant. We wanted to share our experience of using veno-arterial (VA) ECMO as an adjunct to lung recovery and an aide for fluid resuscitation. We present the case of a 77-year-old man with a history of previous single lung transplant who had acute respiratory decompensation and cardiovascular collapse secondary to CMV pneumonia and septic shock. He was cannulated for VA ECMO, treated for CMV pneumonia and resuscitated with 5L of albumin 5% and antibiotics, within 12 hours of cannulation. He required twodays of VA ECMO and was ultimately decannulated and discharged to a rehabilitation facility on hospital day 73. This case emphasizes the challenging clinical scenario of fluid resuscitation in a lung transplant patient. With adequate patient selection, a multidisciplinary team and the use of VA ECMO, success can be achieved.

Hypoalbuminemia is a predictor of mortality in patients with cardiogenic shock requiring veno-arterial extracorporeal membrane oxygenation.

Hypoalbuminemia is predictive of mortality in critically ill patients, especially those with cardiac etiologies of illness. The objective of this study was to determine the association of albumin level pre-cannulation for veno-arterial (V-A) extracorporeal membrane oxygenation (ECMO) and important clinical hospital outcomes. This was a retrospective, observational cohort study of albumin levels in patients with cardiogenic shock requiring V-A ECMO between December 2015 and August 2021 in a single, high-volume ECMO center. The primary outcome was in-hospital mortality. Of 434 patients assessed, 318 were included. The overall mean pre-ECMO albumin was 3 ± 0.8g/dL and mean albumin at 72 hours post-cannulation was 2.7 ± 0.5g/dL. For patients with pre-ECMO albumin ≤3g/dL vs. >3g/dL, in-hospital mortality was 44.9% vs. 27.5%, respectively (p = .002). In multivariable logistic regression analysis, higher albumin (per 1g/dL increase) at time of V-A ECMO initiation was associated with decreased odds of in-hospital mortality (OR, 0.68; 95% CI, 0.48-0.96; p = .03). Patients with a pre-ECMO albumin ≤3g/dL required significantly more platelet transfusions and had higher incidence of gastrointestinal bleeding during V-A ECMO support (both p < .05). Hypoalbuminemia at time of cannulation is significantly associated with in-hospital mortality and ECMO-related complications including platelet transfusion and gastrointestinal bleeding. Albumin levels at the time of consideration of V-A ECMO may serve as a key prognostic indicator and may assist in effective decision-making regarding this invasive and costly resource.

The Effect of Extracorporeal Membrane Oxygenation in the Management of Refractory Ventricular Tachycardia Developed after Fontan Procedure (Case Report)

Aim: to evaluate the effect of extracorporeal membrane oxygenation (ECMO) as a life support in the treatment of a patient with refractory ventricular tachycardia developed after Fontan procedure. Patient and treatment. A 4-year-old child developed refractory ventricular tachycardia (up to 250 bpm) and hemodynamic depression 18 hours after the Fontan procedure. After the failure of cardiopulmonary resuscitation and antiarrhythmic therapy, resternotomy with central venoarterial (VA) ECMO support was performed, followed by diagnostic angiocardiography. Contrast-enhanced cavopulmonary angiography revealed stenosis of the left pulmonary artery, which was treated with balloon angioplasty and stenting.Results. Ventricular tachycardia resolved and sinus rhythm was restored within 24 hours after left pulmonary artery stenting, supported by continuous ECMO and antiarrhythmic therapy. On day 3, transthoracic echocardiography showed good single ventricle contractility after a trial weaning from ECMO. As a result, the ECMO support was removed and the sternum sutured. The patient was discharged from the hospital on day 47 in stable condition.Conclusion. The prompt initiation of VA ECMO support in a 4-year old patient with refractory ventricular tachycardia post-Fontan procedure along with the complex management of post-procedural residual tachycardia using a combination of antiarrhythmic agents helped restoring sinus rhythm and could contribute to preventing neurological complications.

Malnutrition in adult patients treated with venoarterial extracorporeal membrane oxygenation: A descriptive cohort study

ObjectiveTo evaluate malnutrition and its association with outcomes in adult patients requiring venoarterial (VA) extracorporeal membrane oxygenation (ECMO). MethodsPatients cannulated for VA ECMO between January 1, 2020, and January 1, 2023, were screened. Patients on ECMO for <48 hours or without a nutritional evaluation were excluded. Demographic and anthropometric data were collected retrospectively. Malnutrition assessments were conducted using the Global Leadership Initiative on Malnutrition framework. Outcomes analyzed were duration of ECMO and in-hospital mortality. Patients were stratified by admission and discharge nutritional status for analysis. Baseline characteristics were controlled for with propensity score matching. ResultsData from 197 patients was analyzed. The cohort was 68% male. The median duration of ECMO was 139.5 hours (interquartile range [IQR], 94.8-257 hours), and mortality was 35%. Thirty-three patients presented with malnutrition, and 61 developed hospital-acquired malnutrition, for an incidence of 47.7%. Malnutrition at any point was associated with longer duration of ECMO (median, 180 hours [IQR, 107.8-335.8 hours] vs 120 hours [IQR, 90-185.8 hours]; P < .001). Patients with hospital-acquired malnutrition required a 50% longer duration of ECMO (median, 182.5 hours [IQR, 101.5-367 hours] vs 123 hours [IQR, 90.8-211.5 hours]; P < .001). Preexisting malnutrition was associated with a nonsignificant increase in mortality (48.2% vs 32.9%; P = .13), which was similar after 3:1 propensity score matching (43.3% vs 35.4%; P = .44). ConclusionsIn adult patients, malnutrition appears to be associated with prolonged duration of VA ECMO. Adequately powered studies are needed to further investigate the relationship between malnutrition and mortality.

Extracorporeal Membrane Oxygenation Assisted Cardiac Interventions

The use of extracorporeal membrane oxygenation (ECMO) for management of critically ill patients has significantly increased in the recent past due to technological progress and increased experience with safe ECMO runs. The use of venoarterial (VA) ECMO during high risk interventional cardiology procedures ensure adequate cardiac output and other organ perfusion as well. The use of elective VA ECMO support during procedure allow interventionists to perform procedure safely and comfortably, moreover the support may be extended during post-procedural period in case of cardiogenic shock or arrhythmia. VA ECMO may also be instituted in emergent situations when conventional cardiopulmonary resuscitation (CPR) is ineffective to achieve return of spontaneous circulation. The various procedures with high risk potential due to anatomical complexity, haemodynamic decompensation or preexisting clinical condition may require mechanical circulatory support. These include percutaneous coronary interventions, Transcatheter aortic valve implantation (TAVI), complex congenital anamoly or electrophysiological procedures. However an integrated team approach with appropriate communication is vital among interventional cardiologist, ECMO specialist, cardiac surgeon, cardiac anaesthesiologist and perfusionist for a successful outcome.

Perioperative extracorporeal membrane oxygenation in liver transplantation—bridge to transplantation, intraoperative salvage, and postoperative support: outcomes and predictors for survival in a large-volume liver transplant center

Data on perioperative extracorporeal membrane oxygenation (ECMO) in liver transplantation (LT) are scarce. ECMO has been used preoperatively, intraoperatively, and postoperatively for a variety of indications at our center. This retrospective, single-center study of ECMO use peri-LT aimed to describe predictors for successful outcome in this highly select cohort of patients. Demographics, support method, and indication for LT were compared between survivors and nonsurvivors. Twenty-nine patients received venovenous (V-V; n = 20), venoarterial (V-A; n = 8), and venoarteriovenous (n = 1) ECMO. Twelve (41.4%) patients were bridged to emergency LT for acute liver failure, and emergency redo LT. Four (13.3%) patients required intraoperative V-A ECMO salvage, 2 necessitating extracorporeal cardiopulmonary resuscitation. Thirteen (43.3%) patients required ECMO support after LT: V-V ECMO (n = 9); V-A ECMO (n = 1); and extracorporeal cardiopulmonary resuscitation (n = 3) between postoperative days 2 to 30. Overall, 19 patients (65.5%) were successfully weaned off ECMO; 15 (51.7%) survived to intensive care unit discharge. All patients who underwent intraoperative salvage ECMO and all who were bridged to emergency redo LT died. Peri-LT ECMO is feasible. Post-LT ECMO outcomes are encouraging, in particular for V-V ECMO. Intraoperative ECMO salvage, uncontrolled sepsis, and graft failure are associated with poor outcomes.

Peripheral extracorporeal membrane oxygenation in perioperative medicine : Principles, indications and challenges

In recent years the number of patients treated in intensive care units by extracorporeal membrane oxygenation (ECMO) due to severe respiratory failure or cardiogenic shock has steadily increased [1]. Consequently, the number of invasive procedures and operations in these patients has also increased. Afundamental understanding of these systems and the clinical indications is therefore helpful for the practicing (non-cardiac) surgeon. This review article focuses on peripheral ECMO procedures: venovenous (V-V) ECMO for patients with respiratory failure and venoarterial (V-A) ECMO for circulatory support in cardiogenic shock.

Very Delayed Surgical Bleeding after Coronary Artery Bypass Graft Causing Cardiac Tamponade and Cardiogenic Shock: A Rare Case Report

Delayed surgical bleeding from the left internal mammary artery (LIMA) bed following coronary artery bypass grafting (CABG) is a rare yet potentially fatal condition that can lead to cardiac tamponade and life-threatening cardiogenic shock. We present a case of extremely delayed active bleeding from the LIMA bed, occurring 5 weeks after conventional CABG, resulting in cardiac tamponade and cardiogenic shock. The 73-year-old patient presented to the emergency room with a 2-day history of general weakness and hypotension. He had undergone CABG 5 weeks ago. Optimal inotropic agents and vasopressors were used for the treatment of shock. In the emergency room, real-time bedside echocardiography showed severe external compression of the right ventricle by a homogeneous, hyperechoic mass. Veno-arterial (V-A) mode extracorporeal membrane oxygenation (ECMO) was promptly instituted to stabilize hemodynamics. Subsequent chest re-exploration, involving blood clot evacuation, was performed, and the bleed from the distal LIMA bed was ligated. Delayed LIMA bed bleeding causing cardiac tamponade and cardiogenic shock is an infrequent occurrence, and the use of V-A mode ECMO successfully provided a window of time for chest exploration.

Pediatric Hematology and Oncology Patients on Extracorporeal Membrane Oxygenation: Outcomes in a Multicenter, Retrospective Cohort, 2009-2021.

To describe characteristics associated with survival for pediatric patients with an oncologic diagnosis or hematopoietic cell transplant (HCT) supported with extracorporeal membrane oxygenation (ECMO). Multicenter, retrospective study. Sixteen PICUs in the United States and Israel. We included patients aged younger than 19 years with an oncologic diagnosis or HCT who required ECMO support between 2009 and 2021. None. A total of 149 patients were included in the study cohort. There were 118 patients with an oncologic diagnosis and 31 that received HCT. The indications for ECMO were respiratory failure (46%), combined respiratory and cardiac failure (28%), and cardiac failure (25%). Venovenous (V-V) ECMO was used in 45% of patients, with 53% of patients being placed on venoarterial (V-A) ECMO. For oncologic and HCT groups, survival to ECMO decannulation was 52% (62/118) and 64% (20/31), and survival to hospital discharge was 36% (43/118) and 42% (13/31), respectively. After adjusting for other factors, requiring cardiopulmonary resuscitation was associated with greater odds ratio of mortality (3.0 [95% CI, 1.2-7.7]). Survival to ECMO decannulation of pediatric oncologic and HCT patients in this study was 52-64%, depending upon diagnosis. However, survival to hospital discharge remains poor. Future research should prioritize understanding factors contributing to this survival gap within these patient populations.

Outcome of Veno-Pulmonary Extracorporeal Life Support in Lung Transplantation Using ProtekDuo Cannula: A Systematic Review and Description of Configurations.

Background: Refractory end-stage pulmonary failure may benefit from extracorporeal life support (ECLS) as a bridge to lung transplantation. Veno-venous (VV) extracorporeal membrane oxygenation (ECMO) has been recommended for patients who have failed conventional medical therapy and mechanical ventilation. Veno-arterial (VA) ECMO may be used in patients with acute right ventricular (RV) failure, haemodynamic instability, or refractory respiratory failure. Peripheral percutaneous approaches, either dual-site single-lumen cannulation for veno-pulmonary (VP) ECMO or single-site dual-lumen (dl)VP ECMO, using the ProtekDuo right ventricular assist device (RVAD) cannula, has made this configuration a desirable option as a bridge to transplantation. These configurations support the right ventricle, prevent recirculation by placing the tricuspid and pulmonary valve between the drainage and return cannulas, provide the direct introduction of oxygenated blood into the pulmonary artery, and have been shown to decrease the incidence of acute kidney injury (AKI), requiring continuous renal replacement therapy (CRRT) in certain disease states. This promotes haemodynamic stability, potential sedation-weaning trials, extubation, mobilisation, and pre-transplant rehabilitation. Methods: A web-based literature search in PubMed and EMBASE was undertaken based on a combination of keywords. The PICOS and PRISMA approaches were used. Results: Four case series were identified out of 323 articles, with a total of 34 patients placed on VP ECMO as a bridge to lung transplantation. All relevant data are reviewed and integrated into the Discussion. Conclusions: Despite the limited available evidence, the use of ProtekDuo has become very promising for the management of end-stage lung disease as a bridge to lung transplantation.

Prevalence and Neurological Outcomes of Comatose Patients With Extracorporeal Membrane Oxygenation

To investigate prevalence, risk factors, and in-hospital outcomes of comatose extracorporeal membrane oxygenation (ECMO) patients. Retrospective observational. Tertiary academic hospital. Adults received venoarterial (VA) or venovenous (VV) ECMO support between November 2017 and April 022. None. We defined 24-hour off sedation as no sedative infusion (except dexmedetomidine) or paralytics administration over a continuous 24-hour period while on ECMO. Off-sedation coma (comaoff) was defined as a Glasgow Coma Scale score of ≤8 after achieving 24-hour off sedation. On-sedation coma (comaon) was defined as a Glasgow Coma Scale score of ≤8 during the entire ECMO course without off sedation for 24 hours. Neurological outcomes were assessed at discharge using the modified Rankin scale (good, 0-3; poor, 4-6). We included 230 patients (VA-ECMO 143, 65% male); 24-hour off sedation was achieved in 32.2% VA-ECMO and 26.4% VV-ECMO patients. Among all patients off sedation for 24 hours (n = 69), 56.5% VA-ECMO and 52.2% VV-ECMO patients experienced comaoff. Among those unable to be sedation free for 24 hours (n = 161), 50.5% VA-ECMO and 17.2% VV-ECMO had comaon. Comaoff was associated with poor outcomes (p < 0.05) in VA-ECMO and VV-ECMO groups, whereas comaon only impacted the VA-ECMO group outcomes. In a multivariable analysis, requirement of renal replacement therapy was an independent risk factor for comaoff after adjusting for ECMO configuration, after adjusting for ECMO configuration, acute brain injury, pre-ECMO partial pressure of oxygen in arterial blood, partial pressure of carbon dioxide in arterial blood, pH, and bicarbonate level (worst value within 24 hours before cannulation). Comaoff was common and associated with poor outcomes at discharge. Requirement of renal replacement therapy was an independent risk factor.

New Insights into Hepatic and Intestinal Microcirculation and Pulmonary Inflammation in a Model of Septic Shock and Veno-Arterial Extracorporeal Membrane Oxygenation in the Rat.

Despite significant efforts toward improving therapy for septic shock, mortality remains high. Applying veno-arterial (V-A) extracorporeal membrane oxygenation (ECMO) in this context remains controversial. Since the cannulation of the femoral artery for V-A ECMO return leads to lower body hyperoxia, this study investigated the impact of V-A ECMO therapy on the intestinal and hepatic microcirculation during septic shock in a rodent model. Thirty male Lewis rats were randomly assigned to receive V-A ECMO therapy with low (60 mL/kg/min) or high (90 mL/kg/min) blood flow or a sham procedure. Hemodynamic data were collected through a pressure-volume catheter in the left ventricle and a catheter in the lateral tail artery. Septic shock was induced by intravenous administration of lipopolysaccharide (1 mg/kg). The rats received lung-protective ventilation during V-A ECMO therapy. The hepatic and intestinal microcirculation was measured by micro-lightguide spectrophotometry after median laparotomy for two hours. Systemic and pulmonary inflammation was detected via enzyme-linked immunosorbent assays (ELISA) of the plasma and bronchoalveolar lavage (BAL), respectively, measuring tumor necrosis factor-alpha (TNF-α), interleukins 6 (IL-6) and 10 (IL-10), and C-X-C motif ligands 2 (CXCL2) and 5 (CXCL5). Oxygen saturation and relative hemoglobin concentration were reduced in the hepatic and intestinal microcirculation during V-A ECMO therapy, independent of the blood flow rate. Further, rats treated with V-A ECMO therapy also presented elevated systolic, diastolic, and mean arterial blood pressure and increased stroke volume, cardiac output, and left ventricular end-diastolic volume. However, left ventricular end-diastolic pressure was only elevated during high-flow V-A ECMO therapy. Blood gas analysis revealed a dilutional anemia during V-A ECMO therapy. ELISA analysis showed an elevated plasma CXCL2 concentration only during high-flow V-A ECMO therapy and elevated BAL CXCL2 and CXCL5 concentrations only during low-flow V-A ECMO therapy. Rats undergoing V-A ECMO therapy exhibited impaired microcirculation of the intestine and liver during septic shock despite increased blood pressure and cardiac output. Increased pulmonary inflammation was detected only during low-flow V-A ECMO therapy in septic shock.

A novel rat lung transplantation model using venoarterial extracorporeal membrane oxygenation support

ObjectivesExtracorporeal membrane oxygenation (ECMO) has become an important life support technique during lung transplantation. We aimed to develop a rat model for lung transplantation using venoarterial (VA) ECMO support. MethodsAdult male Sprague-Dawley rats weighing 400 to 450 g were used in this study. ECMO circuits were created by obtaining venous access from the femoral vein with subsequent extracorporeal oxygen exchange, which was then returned to the circulatory system through the left carotid artery (ie, VA-ECMO). Simultaneously, the donor lungs were retrieved and immersed in cold, low-potassium dextran lung preservation solution. Orthotopic left lung transplantation supported by VA-ECMO was performed. Thereafter, a respiratory failure rat model was constructed using ventilation with a hypoxic and hypercapnic gas mixture, consisting of 6% oxygen, 8% carbon dioxide, and 86% nitrogen, before lung transplantation. Similarly, left lung transplantation supported by VA-ECMO was performed in rats with respiratory failure. Arterial blood gas levels were measured at designated time points throughout the experiment. ResultsWe found that VA-ECMO provided sufficient oxygenation and carbon dioxide removal to allow for smooth left lung transplantation in healthy rats and those with respiratory failure. ConclusionsWe established a rat model for lung transplantation using VA-ECMO. Left lung transplantation using VA-ECMO support is also feasible and safe in rat models of respiratory failure. These models provide efficient and economical models for translational medicine for lung transplantation using ECMO. Moreover, it will be invaluable to evaluate the physiological and pathophysiological roles of ECMO during lung transplantation.

Safety and Feasibility of Neuromuscular Electrical Stimulation in Patients with Extracorporeal Membrane Oxygenation.

Background/Objectives: The aim of this study was to investigate the feasibility and safety of neuromuscular electrical stimulation (NMES) in patients on extracorporeal membrane oxygenation (ECMO) and thoroughly assess any potential adverse events. Methods: We conducted a prospective observational study assessing safety and feasibility, including 16 ICU patients on ECMO support who were admitted to the cardiac surgery ICU from January 2022 to December 2023. The majority of patients were females (63%) on veno-arterial (VA)-ECMO (81%), while the main cause was cardiogenic shock (81%) compared to respiratory failure. Patients underwent a 45 min NMES session while on ECMO support that included a warm-up phase of 5 min, a main phase of 35 min, and a recovery phase of 5 min. NMES was implemented on vastus lateralis, vastus medialis, gastrocnemius, and peroneus longus muscles of both lower extremities. Two stimulators delivered biphasic, symmetric impulses of 75 Hz, with a 400 μsec pulse duration, 5 sec on (1.6 sec ramp up and 0.8 sec ramp down) and 21 sec off. The intensity levels aimed to cause visible contractions and be well tolerated. Primary outcomes of this study were feasibility and safety, evaluated by whether NMES sessions were successfully achieved, and by any adverse events and complications. Secondary outcomes included indices of rhabdomyolysis from biochemical blood tests 24 h after the application of NMES. Results: All patients successfully completed their NMES session, with no adverse events or complications. The majority of patients achieved type 4 and 5 qualities of muscle contraction. Conclusions: NMES is a safe and feasible exercise methodology for patients supported with ECMO.

Clinical Outcomes With Extracorporeal Membrane Oxygenation for Interstitial Lung Disease: Systematic Review and Meta-Analysis.

The evidence on indications, outcomes, and complications with the use of extracorporeal membrane oxygenation (ECMO) in the setting of interstitial lung disease (ILD) is limited in the existing literature. We performed a systematic review and meta-analysis for the use of ECMO in the setting of ILD to study the prognostic factors associated with in-hospital mortality. Eighteen unique studies with a total of 1,356 patients on ECMO for ILD were identified out of which 76.5% were on ECMO as a bridge to transplant (BTT) and the rest as a bridge to recovery (BTR). The overall in-hospital mortality was 45.76%, with 71.3% and 37.8% for BTR and BTT, respectively. Among the various prognostic factors, mortality was lower with younger age (mean difference = 3.15, 95% confidence interval [CI] = 0.82-5.49), use of awake veno-arterial (VA)-ECMO compared to veno-venous (VV)-ECMO (unadjusted odds ratio [OR] = 0.22, 95% CI = 0.13-0.37) in the overall cohort. In the setting of BTT, the use of VA-ECMO had a decreased hazard ratio (HR) compared to VV-ECMO (adjusted HR = 0.34, 95% CI = 0.15-0.81, p = 0.015). The findings of our meta-analysis are critical but are derived from retrospective studies with small sample sizes and thus are of low to very low-GRADE certainty.