What Is the Optimal Blood Pressure on Veno-Arterial Extracorporeal Membrane Oxygenation? Impact of Mean Arterial Pressure on Survival

Pulmonary Artery Pressures and Mortality During Venoarterial ECMO: An ELSO Registry Analysis

BACKGROUND

Systemic hemodynamics and specific ventilator settings have been shown to predict survival during venoarterial extracorporeal membrane oxygenation (ECMO). How the right heart (the right ventricle and pulmonary artery) affect survival during venoarterial ECMO is unknown. We aimed to identify the relationship between right heart function with mortality and the duration of ECMO support.

METHODS

Cardiac ECMO runs in adults from the Extracorporeal Life Support Organization Registry between 2010 and 2022 were queried. Right heart function was quantified via pulmonary artery pulse pressure (PAPP) for pre-ECMO and on-ECMO periods. A multivariable model was adjusted for modified Society for Cardiovascular Angiography and Interventions stage, age, sex, and concurrent clinical data (ie, pulmonary vasodilators and systemic pulse pressure). The primary outcome was in-hospital mortality.

RESULTS

A total of 4442 ECMO runs met inclusion criteria and had documentation of hemodynamic and illness severity variables. The mortality rate was 55%; nonsurvivors were more likely to be older, have a worse Society for Cardiovascular Angiography and Interventions stage, and have longer pre-ECMO endotracheal intubation times (P<0.05 for all) than survivors. Increasing PAPP from pre-ECMO to on-ECMO time (ΔPAPP) was associated with reduced mortality per 2 mm Hg increase (odds ratio, 0.98 [95% CI, 0.97-0.99]; P=0.002). Higher on-ECMO PAPP was associated with mortality reduction across quartiles with the greatest reduction in the third PAPP quartile (odds ratio, 0.75 [95% CI, 0.63-0.90]; P=0.002) and longer time on ECMO per 10 mm Hg (beta, 15 [95% CI, 7.7-21]; P<0.001).

CONCLUSIONS

Early on-ECMO right heart function and interval improvement from pre-ECMO values were associated with mortality reduction during cardiac ECMO. Incorporation of right heart metrics into risk prediction models should be considered.

Factors associated with 30-day in-hospital mortality in critically ill adult patients receiving extracorporeal membrane oxygenation: A retrospective cohort study

OBJECTIVE

To identify factors associated with the 30-day in-hospital mortality rate among adult patients requiring extracorporeal membrane oxygenation (ECMO) in intensive care units.

RESEARCH METHODOLOGY

Retrospective cohort study including 148 patients who underwent ECMO for at least 48 h between March 2010 and August 2021. The patients were divided into survivors and non-survivors based on their 30-day in-hospital survival. We obtained the sociodemographic information and pre- and post-ECMO data from electronic medical records. Kaplan-Meier survival curves and Multivariate Cox proportional hazards regression were used to analyse the data.

SETTING

A tertiary-care university hospital in South Korea.

MAIN OUTCOME MEASURES

The 30-day in-hospital mortality rate was the principal outcome measure.

RESULTS

The 30-day in-hospital mortality rate was 49.3% (n = 73). Kaplan-Meier analysis demonstrated that the duration of ECMO support in the 50th percentile of surviving patients was 13 days. Multivariable Cox regression analysis showed that new-onset renal failure, lower mean arterial pressure, and ECMO weaning failure were associated with an increased 30-day in-hospital mortality risk among patients who received ECMO. Subgroup analysis also revealed a significant association between weaning failure and 30-day in-hospital mortality after adjusting for covariates in patients undergoing veno-arterial ECMO.

CONCLUSION

Close monitoring of post-ECMO renal function and mean arterial pressure is required to minimize the risk of 30-day in-hospital mortality, especially in adults within the first two weeks of ECMO initiation. Moreover, the success of ECMO weaning should be optimized by collaboration within the ECMO team.

IMPLICATIONS FOR CLINICAL PRACTICE

Critical care nurses should pay close attention to patients' response to weaning trials as well as alternations in renal function and mean arterial pressure during ECMO support. Furthermore, developing nursing care guidelines for adult patients receiving ECMO and standardized training programs for nurses in intensive care, are required in Korea.

Neuromonitoring During ECMO Support in Children

Extracorporeal membrane oxygenation is a potentially lifesaving intervention for children with severe cardiac or respiratory failure. It is used with increasing frequency and in increasingly more complex and severe diseases. Neurological injuries are important causes of morbidity and mortality in children treated with extracorporeal membrane oxygenation and include ischemic stroke, intracranial hemorrhage, hypoxic-ischemic injury, and seizures. In this review, we discuss the epidemiology and pathophysiology of neurological injury in patients supported with extracorporeal membrane oxygenation, and we review the current state of knowledge for available modalities of monitoring neurological function in these children. These include structural imaging with computed tomography and ultrasound, cerebral blood flow monitoring with near-infrared spectroscopy and transcranial Doppler ultrasound, and physiological monitoring with electroencephalography and plasma biomarkers. We highlight areas of need and emerging advances that will improve our understanding of neurological injury related to extracorporeal membrane oxygenation and help to reduce the burden of neurological sequelae in these children.

Pulmonary Artery Pressures and Mortality during VA ECMO: An ELSO Registry Analysis

Background

Systemic hemodynamics and specific ventilator settings have been shown to predict survival during venoarterial extracorporeal membrane oxygenation (VA ECMO). While these factors are intertwined with right ventricular (RV) function, the independent relationship between RV function and survival during VA ECMO is unknown.

Objectives

To identify the relationship between RV function with mortality and duration of ECMO support.

Methods

Cardiac ECMO runs in adults from the Extracorporeal Life Support Organization (ELSO) Registry between 2010 and 2022 were queried. RV function was quantified via pulmonary artery pulse pressure (PAPP) for pre-ECMO and on-ECMO periods. A multivariable model was adjusted for Society for Cardiovascular Angiography and Interventions (SCAI) stage, age, gender, and concurrent clinical data (i.e., pulmonary vasodilators and systemic pulse pressure). The primary outcome was in-hospital mortality.

Results

A total of 4,442 ECMO runs met inclusion criteria and had documentation of hemodynamic and illness severity variables. The mortality rate was 55%; non-survivors were more likely to be older, have a worse SCAI stage, and have longer pre-ECMO endotracheal intubation times (P < 0.05 for all) than survivors. Improving PAPP from pre-ECMO to on-ECMO time (Δ PAPP) was associated with reduced mortality per 10 mm Hg increase (OR: 0.91 [95% CI: 0.86-0.96]; P=0.002). Increasing on-ECMO PAPP was associated with longer time on ECMO per 10 mm Hg (Beta: 15 [95% CI: 7.7-21]; P<0.001).

Conclusions

Early improvements in RV function from pre-ECMO values were associated with mortality reduction during cardiac ECMO. Incorporation of Δ PAPP into risk prediction models should be considered.

Effects of varying blood flow rate during peripheral veno-arterial extracorporeal membrane oxygen (V-A ECMO) on left ventricular function measured by two-dimensional strain

Background

We evaluated the effects of varying blood flow rate during peripheral veno-arterial extracorporeal membrane oxygen (V-A ECMO) on left ventricular function measured by two-dimensional strain.

Methods

Adult patients who were supported by peripheral V-A ECMO were recruited. Serial hemodynamic and cardiac performance parameters were measured by transthoracic echocardiogram within the first 48 h after implementation of V-A ECMO. Measurements at 100%, 120%, and 50% of target blood flow (TBF) were compared.

Results

A total of 54 patients were included and the main indications for V-A ECMO were myocardial infarction [32 (59.3%)] and myocarditis [6 (11.1%)]. With extracorporeal blood flow at 50% compared with 100% TBF, the mean arterial pressure was lower [66 ± 19 vs. 75 ± 18 mmHg, p < 0.001], stroke volume was greater [23 (12-34) vs. 15 (8-26) ml, p < 0.001], and cardiac index was higher [1.2 (0.7-1.7) vs. 0.8 (0.5-1.3) L/min/m², p < 0.001]. Left ventricular contractile function measured by global longitudinal strain improved at 50% compared with 100% TBF [-2.8 (-7.6- -0.1) vs. -1.2 (-5.2-0) %, p < 0.001]. Similarly, left ventricular ejection fraction increased [24.4 (15.8-35.5) vs. 16.7 (10.0-28.5) %, p < 0.001] and left ventricular outflow tract velocity time integral increased [7.7 (3.8-11.4) vs. 4.8 (2.5-8.5) cm, p < 0.001]. Adding echocardiographic parameters of left ventricular systolic function to the Survival After Veno-arterial ECMO (SAVE) score had better discriminatory value in predicting eventual hospital mortality (AUROC 0.69, 95% CI 0.55-0.84, p = 0.008) and successful weaning from V-A ECMO (AUROC 0.68, 95% CI 0.53-0.83, p = 0.017).

Conclusion

In the initial period of V-A ECMO support, measures of left ventricular function including left ventricular ejection fraction and global longitudinal strain were inversely related to ECMO blood flow rate. Understanding the heart-ECMO interaction is vital to interpretation of echocardiographic measures of the left ventricle while on ECMO.

Knowledge gaps and research priorities in adult veno-arterial extracorporeal membrane oxygenation: a scoping review

PURPOSE

This scoping review aims to identify and describe knowledge gaps and research priorities in veno-arterial extracorporeal membrane oxygenation (VA-ECMO).

METHODS

An expert panel was recruited consisting of eight international experts from different backgrounds. First, a list of priority topics was made. Second, the panel developed structured questions using population, intervention, comparison and outcomes (PICO) format. All PICOs were scored and prioritized. For every selected PICO, a structured literature search was performed.

RESULTS

After an initial list of 49 topics, eight were scored as high-priority. For most of these selected topics, current literature is limited to observational studies, mainly consisting of retrospective cohorts. Only for ECPR and anticoagulation, randomized controlled trials (RCTs) have been performed or are ongoing. Per topic, a summary of the literature is stated including recommendations for further research.

CONCLUSIONS

This scoping review identifies and presents an overview of knowledge gaps and research priorities in VA-ECMO. Current literature is mostly limited to observational studies, although with increasing attention for this patient population, more RCTs are finishing or ongoing. Translational research, from preclinical trials to high-quality or randomized controlled trials, is important to improve the standard practices in this critically ill patient population. Take-home message This scoping review identifies and presents an overview of research gaps and priorities in VA-ECMO. Translational research, from preclinical trials to high-quality or randomized controlled trials, is important to improve the standard practices in this critically ill patient population.

Urinary liver-type fatty acid-binding protein: A hemodynamic index during extracorporeal membrane oxygenation

We discuss a case in which urinary L-FABP measurements were used to manage a 46-year-old male patient receiving V-A ECMO support. His mean blood pressure was ≥75 mmHg for the first 24 h after the initiation of V-A ECMO, and he experienced a rapid decrease in urinary L-FABP levels.

Oxygen debt repayment in the early phase of veno-arterial extracorporeal membrane oxygenation: a cluster analysis

Introduction

Early oxygen debt repayment is predictive of successful weaning from veno-arterial extracorporeal membrane oxygenation (V-A ECMO). However, studies are limited by the patient cohort’s heterogeneity. This study aimed to understand the early state of oxygen debt repayment and its association with end-organ failure and 30-day survival using cluster analysis.

Methods

A retrospective, single-center study was conducted on 153V-A ECMO patients. Patients were clustered using a two-step cluster analysis based on oxygen debt and its repayment during the first 24 h of ECMO. Primary outcomes were end-organ failure and 30-day survival.

Results

The overall mortality was 69.3%. For cluster analysis, 137 patients were included, due to an incomplete data set. The mortality rate in this subset was 67.9%. Three clusters were generated, representing increasing levels of total oxygen debt from cluster 1 to cluster 3. Thirty-day survival between clusters was significantly different (cluster 1: 46.9%, cluster 2: 23.4%, and cluster 3: 4.8%, p = 0.001). Patients in cluster 3 showed less decrement in liver enzymes, creatinine, and urea blood levels. There were significant differences in the baseline oxygen debt and the need for continuous veno-venous hemofiltration (CVVH) between survivors and non-survivors (p < 0.05). Forty-seven patients (34.3%) migrated between clusters within the first 24 h of support. Among these patients, 43.4% required CVVH. Notably, patients requiring CVVH and who migrated to a cluster with a higher oxygen debt repayment showed better survival rates compared to those who migrated to a cluster with a lower oxygen debt repayment.

Conclusions

Oxygen debt repayment during the first 24 h of V-A ECMO shows to correspond with survival, where the baseline oxygen debt value and the necessity for continuous kidney replacement therapy appear to be influential.

Angiotensin II in Patients With Shock on Mechanical Circulatory Support: A Single-Center Retrospective Case Series

OBJECTIVES

To describe angiotensin II (ANGII) use in patients on mechanical circulatory support (MCS). To evaluate the efficacy and safety of ANGII in patients with shock on MCS.

DESIGN

Retrospective cohort study.

SETTING

A single-center, quaternary care academic medical center.

PARTICIPANTS

The study comprised critically ill patients on MCS.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Fourteen patients were included in this retrospective analysis. The median age was 54 years (44.8, 68.3) and 78.6% were men. Six patients were receiving venoarterial extracorporeal membrane oxygenation support, 4 patients were receiving venovenous extracorporeal membrane oxygenation support, and 4 patients were on left ventricular assist devices. Five patients (36%) achieved hemodynamic response to ANGII at 3 hours, defined as a mean arterial pressure (MAP) of ≥65 mmHg or a 10-mmHg increase in MAP with a decrease or no change in total vasopressor dose. Overall, the median MAP increased from 61 mmHg (51, 73) at baseline to 66 mmHg (58, 71) at 3 hours, and the median norepinephrine dose decreased from 0.45 µg/kg/min (0.28, 0.6) at baseline to 0.2 µg/kg/min (0.18, 0.32) at 3 hours. The in-hospital mortality rate was 78.6%. Two patients experienced severe adverse drug events and 1 patient had a sentinel thrombotic event.

CONCLUSIONS

This study suggested that ANGII may provide a salvage treatment option in patients on MCS with refractory vasodilatory shock. There are several safety considerations with the use of ANGII in these patients. Prospective randomized controlled trials are needed to evaluate the safety and efficacy of ANGII in patients on MCS.

A Review of Pulmonary Arterial Hypertension Treatment in Extracorporeal Membrane Oxygenation: A Case Series of Adult Patients

BACKGROUND

Little data is published describing the use of medications prescribed for pulmonary arterial hypertension (PAH) in patients receiving extracorporeal membrane oxygenation (ECMO). Even though many patients with PAH may require ECMO as a bridge to transplant or recovery, little is reported regarding the use of PAH medications in this setting.

METHODS

This retrospective case series summarizes the clinical experience of 8 patients with PAH receiving ECMO and reviews medication management in the setting of ECMO.

RESULTS

Eight PAH patients, 5 of whom were female, ranging in age from 21 to 61 years old, were initiated on ECMO. Veno-arterial (VA) ECMO was used in 4 patients, veno-venous (VV) ECMO and hybrid ECMO configurations in 2 patients respectively. Common indications for ECMO included cardiogenic shock, bridge to transplant, and cardiac arrest. All patients were on intravenous (IV) prostacyclin therapy at baseline. Refractory hypotension was noted in 7 patients of whom 5 patients required downtitration or discontinuation of baseline PAH therapies. Three patients had continuous inhaled epoprostenol added during their time on ECMO. In patients who were decannulated from ECMO, PAH therapies were typically resumed or titrated back to baseline dosages. One patient required no adjustment in PAH therapy while on ECMO. Two patients were not able to be decannulated from ECMO.

CONCLUSION

The treatment of critically ill PAH patients is challenging given a variety of factors that could affect PAH drug concentrations. In particular, PAH patients on prostacyclin analogues placed on VA ECMO appear to have pronounced systemic vasodilation requiring vasopressors which is alleviated by temporarily reducing the intravenous prostacyclin dose. Patients should be closely monitored for potential need for rapid titrations in prostacyclin therapy to maintain hemodynamic stability.

Atrial Septostomy for Left Ventricular Unloading During Extracorporeal Membrane Oxygenation for Cardiogenic Shock: Animal Model

OBJECTIVES

The aim of this study was to quantify and understand the unloading effect of percutaneous balloon atrial septostomy (BAS) in acute cardiogenic shock (CS) treated with venoarterial (VA) extracorporeal membranous oxygenation (ECMO).

BACKGROUND

In CS treated with VA ECMO, increased left ventricular (LV) afterload is observed that commonly interferes with myocardial recovery or even promotes further LV deterioration. Several techniques for LV unloading exist, but the optimal strategy and the actual extent of such procedures have not been fully disclosed.

METHODS

In a porcine model (n = 11; weight 56 kg [53-58 kg]), CS was induced by coronary artery balloon occlusion (57 minutes [53-64 minutes]). Then, a step-up VA ECMO protocol (40-80 mL/kg/min) was run before and after percutaneous BAS was performed. LV pressure-volume loops and multiple hemoglobin saturation data were evaluated. The Wilcoxon rank sum test was used to assess individual variable differences.

RESULTS

Immediately after BAS while on VA ECMO support, LV work decreased significantly: pressure-volume area, end-diastolic pressure, and stroke volume to ∼78% and end-systolic pressure to ∼86%, while superior vena cava and tissue oximetry did not change. During elevating VA ECMO support (40-80 mL/kg/min) with BAS vs without BAS, we observed 1) significantly less mechanical work increase (122% vs 172%); 2) no end-diastolic volume increase (100% vs 111%); and 3) a considerable increase in end-systolic pressure (134% vs 144%).

CONCLUSIONS

In acute CS supported by VA ECMO, atrial septostomy is an effective LV unloading tool. LV pressure is a key component of LV work load, so whenever LV work reduction is a priority, arterial pressure should carefully be titrated low while maintaining organ perfusion.

Intraoperative Management of Adult Patients on Extracorporeal Membrane Oxygenation: An Expert Consensus Statement From the Society of Cardiovascular Anesthesiologists-Part II, Intraoperative Management and Troubleshooting

In the second part of the Society of Cardiovascular Anesthesiologists Extracorporeal Membrane Oxygenation (ECMO) working group expert consensus statement, venoarterial (VA) and venovenous (VV) ECMO management and troubleshooting in the operating room are discussed. Expert consensus statements are provided about intraoperative monitoring, anesthetic drug dosing, and management of intraoperative problems in VA and VV ECMO patients.

Predictors of poor outcome after extra-corporeal membrane oxygenation for refractory cardiac arrest (ECPR): A post hoc analysis of a multicenter database

BACKGROUND

The objective was to assess predictors for unfavorable neurological outcome (UO) in out-of-hospital (OHCA) and in-hospital (IHCA) cardiac arrest patients treated with Extracorporeal cardiopulmonary resuscitation (ECPR).

METHODS

A post hoc analysis of retrospective data from five European ECPR centers (January 2012-December 2016) was performed. The primary composite endpoint was 3-month UO defined as survival with a cerebral performance category (CPC) of 3-4 or death (CPC 5).

RESULTS

A total of 413 patients treated with ECPR were included (median age was 57 [48-65] years, male gender 78%): 61% of patients (n = 250) suffered OHCA. The median time from collapse to ECMO placement was 63 [45-82] minutes. Overall, 81% patients (n = 333) showed unfavorable UO, which was higher in OHCA patients (90% vs 66%), as compared to IHCA. In OHCA, prolonged time from collapse to ECMO initiation (OR 1.02, p < 0.01) and higher ECMO blood flow (OR 1.99, p = 0.01) were associated with UO while initial shockable rhythm (OR 0.04, p < 0.01), previous heart disease (OR 0.20, p < 0.01) and pre-hospital hypothermia (OR 0.08, p < 0.01) had a protective role. In IHCA, prolonged time from arrest to ECMO implantation (OR 1.02, p = 0.03), high lactate level on admission (OR 1.15, p < 0.01) and higher body weight (OR 1.03, p < 0.01) were independently associated with UO.

CONCLUSIONS

IHCA and OHCA patients receiving ECPR have different predictors of UO at presentation, suggesting that selection criteria for ECPR should be decided according to the location of CA. After ECMO initiation, ECMO blood flow management and mean arterial pressure targets might also impact neurological recovery.

Mechanical Cardiac Circulatory Support: an Overview of the Challenges for the Anesthetist

Purpose of Review

Owing to increased utilization of Mechanical Circulatory Support (MCS) devices, patients with these devices frequently present for surgeries requiring anesthetic support. The current article provides basics of perioperative management of these devices.

Recent Findings

Use of extracorporeal membrane oxygenation (ECMO) and left ventricular assist devices (LVADs) are on the rise with recently updated management guidelines. Veno-venous ECMO utilization has been widely utilized as a salvage therapy during the COVID-19 pandemic.

Summary

Intra-Aortic Balloon Pumps continue to be one of the most frequently used devices after acute myocardial infarction. ECMO is utilized for pulmonary or cardiopulmonary support as salvage therapy. LVADs are used in patients with end-stage heart failure as a destination therapy or bridge to transplant. Each of these devices present with their own set of management challenges. Anesthetic management of patients with MCS devices requires a thorough understanding of underlying operating and hemodynamic principles.

Neurological Complications of Veno-Arterial Extracorporeal Membrane Oxygenation: A Retrospective Case-Control Study

Background: To explore the epidemiology, clinical features, risk indicators, and long-term outcomes of neurological complications caused by veno-arterial extracorporeal membrane oxygenation (V-A ECMO).

Methods: We retrospectively analyzed 60 adult patients who underwent V-A ECMO support in our unit from February 2012 to August 2020. These patients were separated into the neurological complications group (NC group) and the non-neurological complications group (nNC group). The differences in basic data and ECMO data between the two groups were compared. The data of long-term neurological prognosis were collected by telephone follow-up.

Results: Thirty-nine patients (65.0%) had neurological complications. There were significant differences between the two groups in terms of median age, hypertension, median blood urea nitrogen, median troponin I (TNI), median lactic acid, pre-ECMO percutaneous coronary intervention, continuous renal replacement therapy (CRRT), median Sequential Organ Failure Assessment score, median Acute Physiology and Chronic Health Evaluation II score, median peak inspiratory pressure, median positive end expiratory pressure, and median fresh frozen plasma (P < 0.05). The median Intensive Care Unit length of stay (ICU LOS), 28-day mortality, median post-ECMO vasoactive inotropic score, non-pulsate perfusion (NP), and median ECMO duration of the NC group were significantly higher than those of the nNC group (P < 0.05). Furthermore, multiple logistic regression analysis revealed that TNI (P = 0.043), CRRT (P = 0.047), and continuous NP > 12 h (P = 0.043) were independent risk indicators for neurological complications in patients undergoing ECMO. Forty-four patients (73.3%) survived after discharge, and 38 patients (63.3%) had Cerebral Performance Category score of 1–2. And there were significant differences between the two groups in long-term neurological outcomes after discharge for 6 months (P < 0.05).

Conclusion: The incidence of neurological complications was higher in patients undergoing V-A ECMO and was closely related to adverse outcomes (including ICU LOS and 28-day mortality). TNI, CRRT, and continuous NP > 12 h were independent risk indicators for predicting neurological complications in ECMO supporting patients. And the neurological complications of patients during ECMO support had significant adverse effect on long-term surviving and neurological outcomes of patients after discharge for 6 months.

Brain Injury in Extracorporeal Membrane Oxygenation: A Multidisciplinary Approach

Extracorporeal membrane oxygenation (ECMO) represents an established technique to provide temporary cardiac and/or pulmonary support. ECMO, in veno-venous, veno-arterial or in extracorporeal carbon dioxide removal modality, is associated with a high rate of brain injuries. These complications have been reported in 7 to 15% of adults and 20% of neonates, and are associated with poor survival. Thromboembolic events, loss of cerebral autoregulation, alteration of the blood-brain barrier, and hemorrhage related to anticoagulation represent the main causes of severe brain injury during ECMO. The most frequent forms of acute neurological injuries in ECMO patients are intracranial hemorrhage (2-21%), ischemic stroke (2-10%), seizures (2-6%), and hypoxic-ischemic brain injury; brain death may also occur in this population. Other frequent complications are infarction (1-8%) and cerebral edema (2-10%), as well as neuropsychological and psychiatric sequelae, including posttraumatic stress disorder.

Achieving sustained extrauterine life: Challenges of an artificial placenta in fetal pigs as a model of the preterm human fetus

Artificial placenta (AP) technology aims to maintain fetal circulation, while promoting the physiologic development of organs. Recent reports of experiments performed in sheep indicate the intrauterine environment can be recreated through the cannulation of umbilical vessels, replacement of the placenta with a low-resistance membrane oxygenator, and incubation of the fetus in fluid. However, it remains to be seen whether animal fetuses similar in size to the extremely preterm human infant that have been proposed as a potential target for this technology can be supported in this way. Preterm Yucatan miniature piglets are similar in size to extremely preterm human infants and share similar umbilical cord anatomy, raising the possibility to serve as a good model to investigate the AP. To characterize fetal cardiovascular physiology, the carotid artery (n = 24) was cannulated in utero and umbilical vein (UV) and umbilical artery were sampled. Fetal UV flow was measured by MRI (n = 16). Piglets were delivered at 98 ± 4 days gestation (term = 115 days), cannulated, and supported on the AP (n = 12) for 684 ± 228 min (range 195-3077 min). UV flow was subphysiologic (p = .002), while heart rate was elevated on the AP compared with in utero controls (p = .0007). We observed an inverse relationship between heart rate and UV flow (r2  = .4527; p < .001) with progressive right ventricular enlargement that was associated with reduced contractility and ultimately hydrops and circulatory collapse. We attribute this to excessive afterload imposed by supraphysiologic circuit resistance and augmented sympathetic activity. We conclude that short-term support of the preterm piglet on the AP is feasible, although we have not been able to attain normal fetal physiology. In the future, we propose to investigate the feasibility of an AP circuit that incorporates a centrifugal pump in our miniature pig model.

Aggressive placement of distal limb perfusion catheter in venoarterial extracorporeal membrane oxygenation

Objective:

The aim of this study is to review the impacts of aggressive placement of a distal perfusion catheter on the outcomes in patients supported with venoarterial extracorporeal membrane oxygenation via femoral cannulation.

Methods:

Analysis was performed with 143 consecutive femoral venoarterial extracorporeal membrane oxygenation cannulation. Patients were divided into two groups: the early period (October 2010 to December 2012, N = 47) where placement of a distal perfusion catheter was attempted percutaneously but not surgically and the late period (January 2013 to November 2018, N = 96) in which placement of distal perfusion catheter was aggressively utilized both percutaneously and surgically. The modification of venoarterial extracorporeal membrane oxygenation cannulation protocol for the late period involved (1) an immediate insertion of a distal perfusion catheter regardless of the size of femoral arterial cannula, (2) an open insertion of a distal perfusion catheter if percutaneous approach failed, and (3) when venoarterial extracorporeal membrane oxygenation cannulation was completed at a non-extracorporeal membrane oxygenation cannulation center, it was encouraged that they attempt insertion of a distal perfusion catheter at the time of cannulation.

Results:

In the late period, a distal perfusion catheter was placed in 96% (92/96) which was significantly increased from 66% (31/47) in the early period. Of these 92 patients in late period, nine patients (9.8%) required open direct insertion of a distal perfusion catheter. The incidence of lower limb ischemia (early vs. late period 26% vs 12%, P = 0.031) was significantly decreased in the late period. Logistic regression analyses showed that distal perfusion catheter placement was the only factor for preventing lower limb ischemia.

Conclusion:

Aggressive insertion of a distal perfusion catheter even utilizing surgical cut-down technique was shown to decrease the incidence of distal limb complications.

Outcomes of end-organ function and survival with veno-arterial extracorporeal membrane oxygenation

INTRODUCTION

Extracorporeal Membrane Oxygenation (ECMO) is a temporary therapy option for refractory cardiac or respiratory failure. Preliminary study suggests that ECMO aids in the recovery of end-organ function by maintaining systemic perfusion.

METHODS

A retrospective IRB approved database research and chart review was performed on patients initiated on veno-arterial (VA-) ECMO between September 2010 and April 2019. End-organ injury markers were compared between the pre-ECMO period, defined as markers recorded before ECMO initiation, and the pre-decannulation period, defined as markers prior to ECMO decannulation. Data was expressed with mean ± standard deviation, or median [quartile 1, quartile 3] and compared between Pre-ECMO and per-decannulation period.

RESULTS

Among the 159 VA-ECMO patients, 100 patients (63%) survived ECMO with mean ECMO duration 10 ± 7 days. Within the survival group, 78 patients (49%) weaned to recovery, and 22 patients (14%) weaned off to durable implantable devices. Compared to the pre-ECMO period, the pre-decannulation period significantly improved in pH (7.23 ± 0.19 vs. 7.40 ± 0.09; p < 0.001) and lactate (5.5 [2.3, 9.0] vs. 1.6 [0.9, 2.3]; p < 0.001), and serum creatinine (1.4 [1.1, 2.1] vs. 1.1 [0.8, 1.7]; p < 0.001). Significant changes were noted in ventilation parameters as well, such as FiO₂ (100 [100, 100] vs. 50 [50, 50]; p < 0.001), PaO₂ (88 [62, 135], 126 [87, 162]; p < 0.001) and PEEP (8.0 [5.0, 12.0] vs. 5.0 [5.0, 8.0]; p < 0.001).

CONCLUSION

Maintaining perfusion with VA-ECMO utilization on indicated patients demonstrated improvements in end-organ functions. Survival rates of VA-ECMO patients were also optimistic.

Extracorporeal Membrane Oxygenation in Transport Part 2: Complications and Troubleshooting

Factors taken for granted while the extracorporeal membrane oxygenation (ECMO) patient is maintained in a hospital setting can become critical when planning for transport. These issues include but are not limited to positioning of patients on a small transport stretcher, positioning of cannulas and equipment, ensuring adequate power sources and supply, inefficient temperature control, and a much higher risk of decannulation. It is paramount to be comfortable with the management strategies required to handle common complications of ECMO with limited resources in a relatively austere environment. Coagulopathy and bleeding are the most common complications occurring in up to 50% of ECMO patients. Loss of flow and hypotension from loss of volume or profound vasodilation after ECMO initiation need to be managed accordingly. Oxygenator malfunction can occur, and clinicians must be able to recognize the indicators of this complication promptly. Loss of pulsatility, low end-tidal carbon dioxide (ETCO₂), and differential hypoxia are common complications in venoarterial ECMO. In addition, an air embolism is life-threatening on venoarterial ECMO but may be better tolerated in the setting of venovenous ECMO. Recirculation in venovenous ECMO leads to circulation of poorly oxygenated blood and must be recognized and addressed. Lastly, pump failure, circuit rupture, and decannulation are devastating complications. Over the last decade, the use of extracorporeal membrane oxygenation (ECMO) has accelerated rapidly,^1-3 providing support for patients in severe respiratory or cardiac failure. With ongoing clinical experience and improvements in technology, the indications for ECMO are increasing.⁴ Many areas are developing centralized ECMO centers to serve their surrounding communities.^5-7 To use a centralized ECMO referral model, patients need access to effective, safe critical care transport, but transporting a patient on ECMO carries a significant risk of adverse events.^8-13 The purpose of this review is to highlight some of the most common adverse events in ECMO transports and provide management suggestions. Note that these recommendations are not a substitution for close collaboration with medical control, and all adverse events should be promptly reported per organizational protocols.

Comparing in-patient extracorporeal cardiopulmonary resuscitation to standard cardiac treatment group of extracorporeal membrane oxygenation patients: 8 years of experience at a single institution

INTRODUCTION

Post-cardiac arrest survivals remain low despite the effort of cardiopulmonary resuscitation. Utilization of extracorporeal membrane oxygenation during cardiopulmonary resuscitation (extracorporeal cardiopulmonary resuscitation) can provide immediate cardiovascular support and potentially improve outcomes of patients with cardiac arrest requiring cardiopulmonary resuscitation. There is renewed interest in the use of extracorporeal cardiopulmonary resuscitation due to improved outcomes over the years.

METHODS

Extracorporeal membrane oxygenation data between 2010 and 2018 were reviewed. Patients with extracorporeal membrane oxygenation placed under cardiopulmonary resuscitation were identified, and demographics, extracorporeal membrane oxygenation survival, survival to discharge, and neurological recovery were retrospectively analyzed with institutional review board approval.

RESULTS

Among 230 cases of extracorporeal membrane oxygenation, 34 (21 males and 13 females, age of 49 ± 13 years) underwent extracorporeal cardiopulmonary resuscitation. The mean duration of extracorporeal membrane oxygenation support after extracorporeal cardiopulmonary resuscitation was 8.3 ± 7.9 days. Extracorporeal membrane oxygenation mortality among extracorporeal cardiopulmonary resuscitation patients was 32% (11/34) and hospital survival was 38% (13/34), which are similar to standard cardiac extracorporeal membrane oxygenation (extracorporeal membrane oxygenation survival 62% and hospital survival 39% in cardiac extracorporeal membrane oxygenation). Among the extracorporeal membrane oxygenation death after extracorporeal cardiopulmonary resuscitation, the majority was due to neurological injury (73%, 8/11); 8/34 extracorporeal membrane oxygenation survival rate and 30-day survival rate were 63% and 25% in early half of study (2010-2014) and have improved to 70% and 60% in late half of study (2014-2018).

CONCLUSION

Over years of experience with extracorporeal membrane oxygenation, the outcome of the extracorporeal cardiopulmonary resuscitation has been improving and appears to exceed those of traditional methods, despite limited sample size. Neurological complications still need to be addressed in order for survival and outcomes to improve.