Contemporary extracorporeal membrane oxygenation therapy in adults: Fundamental principles and systematic review of the evidence

Driving pressure in mechanical ventilation: A review

Driving pressure (∆P) is a core therapeutic component of mechanical ventilation (MV). Varying levels of ∆P have been employed during MV depending on the type of underlying pathology and severity of injury. However, ∆P levels have also been shown to closely impact hard endpoints such as mortality. Considering this, conducting an in-depth review of ∆P as a unique, outcome-impacting therapeutic modality is extremely important. There is a need to understand the subtleties involved in making sure ∆P levels are optimized to enhance outcomes and minimize harm. We performed this narrative review to further explore the various uses of ∆P, the different parameters that can affect its use, and how outcomes vary in different patient populations at different pressure levels. To better utilize ∆P in MV-requiring patients, additional large-scale clinical studies are needed.

Using Signal Features of Functional Near-Infrared Spectroscopy for Acute Physiological Score Estimation in ECMO Patients

Extracorporeal membrane oxygenation (ECMO) is a vital emergency procedure providing respiratory and circulatory support to critically ill patients, especially those with compromised cardiopulmonary function. Its use has grown due to technological advances and clinical demand. Prolonged ECMO usage can lead to complications, necessitating the timely assessment of peripheral microcirculation for an accurate physiological evaluation. This study utilizes non-invasive near-infrared spectroscopy (NIRS) to monitor knee-level microcirculation in ECMO patients. After processing oxygenation data, machine learning distinguishes high and low disease severity in the veno-venous (VV-ECMO) and veno-arterial (VA-ECMO) groups, with two clinical parameters enhancing the model performance. Both ECMO modes show promise in the clinical severity diagnosis. The research further explores statistical correlations between the oxygenation data and disease severity in diverse physiological conditions, revealing moderate correlations with the acute physiologic and chronic health evaluation (APACHE II) scores in the VV-ECMO and VA-ECMO groups. NIRS holds the potential for assessing patient condition improvements.

Traumatic main airway rupture successfully rescued by extracorporeal membrane oxygenation: A case report

The chest is a common site for traumatic injury; however, rupture of the main airway after chest trauma is a rare and potentially fatal condition. The present study demonstrated that extracorporeal membrane oxygenation (ECMO) may serve a crucial role in the effective conventional treatment of patients with severe chest trauma, ECMO was used before tracheal repair surgery to prevent hypoxia during surgery. When effective ventilation of the patient cannot occur without assistance, ECMO support is considered to be essential in ensuring effective gas exchange. This rescue procedure can provide guidance for the treatment of patients suffering from traumatic tracheal rupture and respiratory failure. To summarize, ECMO may be able to improve the treatment experience of patients with traumatic tracheal rupture and increase the treatment success rate of such patients.

Bleeding Complications in COVID-19 Critically Ill ARDS Patients Receiving VV-ECMO Therapy

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) therapy is rapidly expanding worldwide, yet this therapy has a serious risk of bleeding. Whether coagulation-activating viral infections such as COVID-19 may have an impact on the risk of bleeding is largely unknown. This study conducted a monocentric investigation of severely affected COVID-19 patients receiving VV-ECMO therapy with regard to the occurrence and possible influences of minor and major bleeding and transfusion requirements. Among the 114 included study patients, we were able to assess more than 74,000 h of VV-ECMO therapy. In these, 103 major bleeding events and 2283 minor bleeding events were detected. In total, 1396 red blood concentrates (RBCs) were administered. A statistically significant correlation with the applied anticoagulation or demographic data of the patients was not observed. Contrary to the frequently observed thromboembolic complications among COVID-19 patients, patients with VV-ECMO therapy, even under low-dose anticoagulation, show a distinct bleeding profile, especially of minor bleeding, with a substantial need for blood transfusions. COVID-19 patients show a tendency to have frequent bleeding and require repeated RBC transfusions during VV-ECMO. This fact might not be solely explained by the mechanical alteration of ECMO or anticoagulation.

Update on Anticoagulation Strategies in Patients with ECMO-A Narrative Review

The use of extracorporeal membrane oxygenation (ECMO) has recently increased exponentially. ECMO has become the preferred mode of organ support in refractory respiratory or circulatory failure. The fragile balance of haemostasis physiology is massively altered by the patient's critical condition and specifically the aetiology of the underlying disease. Furthermore, an application of ECMO conveys another disturbance of haemostasis due to blood-circuit interaction and the presence of an oxygenator. The purpose of this review is to summarise current knowledge on the anticoagulation management in patients undergoing ECMO therapy. The unfractionated heparin modality with monitoring of activated partial thromboplastin tests is considered to be a gold standard for anticoagulation in this specific subgroup of intensive care patients. However, alternative modalities with other agents are comprehensively discussed. Furthermore, other ways of monitoring can represent the actual state of coagulation in a more complex fashion, such as thromboelastometric/graphic methods, and might become more frequent. In conclusion, the coagulation system of patients with ECMO is altered by multiple variables, and there is a significant lack of evidence in this area. Therefore, a highly individualised approach is the best solution today.

Effect of intra-aortic balloon pump with veno-arterial extracorporeal membrane oxygenation in acute myocardial infarction with cardiogenic shock: A meta-analysis

BACKGROUND

The effectiveness of a concomitant intra-aortic balloon pump (IABP) with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) intervention in acute myocardial infarction with cardiogenic shock (AMICS) patients is contested in the literature. This study sought to compare short-term mortality weaning rate from VA-ECMOin AMICS cases.

METHODS

We conducted a literature review and compared the primary and secondary endpoints in the following treatment groups of AMICS patients: (1) VA-ECMO plus IABP vs. IABP alone and (2) VA-ECMO plus IABP vs. VA-ECMO alone. The primary endpoint was in-hospital all-cause mortality; while 30-days mortality, weaning from VA-ECMO, and vascular complications comprised secondary endpoints.

RESULTS

VA-ECMO concomitant with IABP was administered to 3,580 (76.4%) patients, while IABP alone and VA-ECMO alone treatments accounted for 1.7% and 21.9% of the patients, respectively. We found that in-hospital mortality was significantly lower in patients treated with VA-ECMO plus IABP vs. VA-ECMO alone (odds ratio (OR) = 0.52; 95% Confidence Interval (CI) = 0.21-1.31; I-squared statistic (I2 = 30%) or IABP alone (OR = 0.20; 95% CI = 0.08-0.55; I2 = 0%). Additionally, 30-days mortality was significantly lower in patients treated with VA-ECMO plus IABP vs. VA-ECMO alone (OR = 0.31; 95% CI = 0.25-0.40; I2 = 0%) or IABP alone (OR = 0.24; 95% CI = 0.11-0.50; I2 = 0%). A significant difference was observed in weaning from VA-ECMO in patients treated with VA-ECMO plus IABP vs. VA-ECMO alone (OR = 1.91; 95% CI = 1.09-3.33; I2 = 0%).

CONCLUSION

In-hospital and 30-days mortality were significantly lower in AMICS patients treated with VA-ECMO plus IABP vs. VA-ECMO alone or IABP alone. VA-ECMO with concomitant IABP could increase the proportion of patients weaned from VA-ECMO, significantly reducing in-hospital mortality, without increasing complications.

Effect of Hospital Volume on Outcome of Extracorporeal Membrane Oxygenation Support - Nationwide Population-Based Cohort Study in Taiwan

BACKGROUND

In modern critical care, extracorporeal membrane oxygenation (ECMO) is crucial in the management of severe respiratory and cardiac failure. Nationwide studies of the relationship between hospital volume and outcomes of ECMO use are unavailable.

METHODS AND RESULTS

Using Taiwan's National Health Insurance Research Database, we identified 11,734 adult patients who received ECMO support in 101 hospitals between January 1, 2001, and December 31, 2017. Outcomes included in-hospital mortality, 1-year mortality, and ECMO-related complications. Cox proportional hazards model, locally estimated scatterplot smoothing, and restricted cubic spline regression were used to analyze the volume-outcome relationship. The overall in-hospital mortality rate was 65.5%, and the 1-year mortality rate was 70.6% in this database. The 101 hospitals were divided into 4 groups based on annual volume. The in-hospital and 1-year mortality rates were significantly lower in the high-volume group (annual volume >40) than in the low-volume group (annual volume <10).

CONCLUSIONS

For critical care, high-volume hospitals have superior short-term and mid-term outcomes. To make the medical system equitable and reasonable, establishing a rapid and efficient nationwide referral system should be considered.

Therapy and Outcome of Prolonged Veno-Venous ECMO Therapy of Critically Ill ARDS Patients

Veno-venous Extracorporeal Membrane Oxygenation (VV-ECMO) therapy has become increasingly used and established in many hospitals as a routine treatment. With ECMO-therapy being a resource-demanding procedure, it is of interest whether a more prolonged VV-ECMO treatment would hold sufficient therapeutic success. Our retrospective study included all VV-ECMO runs from 1 January 2020 to 31 June 2022. We divided all runs into four groups (<14 days, 14-27, 28-49, 50+) of different durations and looked for differences overall in hospital survival. Additionally, corresponding treatments and therapeutic modalities, as well as laboratory results, were analyzed. We included 117 patients. Of those, 97 (82.9%) received a VV-ECMO treatment longer than two weeks. We did not find a significant association between ECMO duration (p = 0.15) and increased mortality though a significant correlation between the patients' age and their probability of survival (p = 0.02). Notably, we found significantly lower interleukin-6 levels with an increase in therapy duration (p < 0.01). Our findings show no association between the duration of ECMO therapy and mortality. Thus, the treatment duration alone may not be used for making assumptions about the prospect of survival. However, attention is also increasingly focused on long-term outcomes, such as post-intensive care syndrome with severe impairments.

Early Use of Extracorporeal Membrane Oxygenation for Traumatically Injured Patients: A National Trauma Database Analysis

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) in acute trauma patients is a poorly characterized event. While ECMO most commonly has been deployed for advanced cardiopulmonary or respiratory failure following initial resuscitation, growing levels of evidence for out of hospital cardiac arrest support early ECMO cannulation as part of resuscitative efforts. We sought to perform a descriptive analysis evaluating traumatically injured patients, who were placed on ECMO, during their initial resuscitation period.

METHODS

We performed a retrospective analysis of the Trauma Quality Improvement Program Database from 2017 to 2019. All traumatically injured patients who received ECMO within the first 24 hours of their hospitalization were assessed. Descriptive statistics were used to define patient characteristics and injury patterns associated with the need for ECMO, while mortality represented the primary outcome evaluated.

RESULTS

A total of 696 trauma patients received ECMO during their hospitalization, of which 221 were placed on ECMO within the first 24 hours. Early ECMO patients were on average 32.5 years old, 86% male, and sustained a penetrating injury 9% of the time. The average ISS was 30.7, and the overall mortality rate was 41.2%. Prehospital cardiac arrest was noted in 18.2% of the patient population resulting in a 46.8% mortality. Of those who underwent resuscitative thoracotomy, a 53.3% mortality rate was present.

CONCLUSION

Early cannulation for ECMO in severely injured patients may provide an opportunity for rescue therapy following severe injury patterns. Further evaluation regarding the safety profile, cannulation strategies, and optimal injury patterns for these techniques should be evaluated.

Veno-venous extracorporeal membrane oxygenation for the treatment of respiratory compromise

Extracorporeal membrane oxygenation for the purpose of intervening upon profound cardiovascular or pulmonary compromise has proven to be a worthy intervention. Technological advancements have allowed this mode of therapy to become more effective and widespread. Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is a commonly used strategy to help manage patients with pulmonary dysfunction refractory to traditional management methods. This review intends to focus upon common indications and the clinical considerations for the institution of VV-ECMO as well as some of its known complications.

Spinal Cord Infarction With Prolonged Femoral Venoarterial Extracorporeal Membrane Oxygenation

OBJECTIVES

There have been sporadic reports of ischemic spinal cord injury (SCI) during venoarterial extracorporeal membrane oxygenation (VA-ECMO) support. The authors observed a troubling pattern of this catastrophic complication and evaluated the potential mechanisms of SCI related to ECMO.

DESIGN

This study was a case series.

SETTING

This study was performed at a single institution in a University setting.

PARTICIPANTS

Patients requiring prolonged VA-ECMO were included.

INTERVENTIONS

No interventions were done. This was an observational study.

MEASUREMENTS AND MAIN RESULTS

Four hypotheses of etiology were considered: (1) hypercoagulable state/thromboembolism, (2) regional hypoxia/hypocarbia, (3) hyperperfusion and spinal cord edema, and (4) mechanical coverage of spinal arteries. The SCI involved the lower thoracic (T7-T12 level) spinal cord to the cauda equina in all patients. Seven out of 132 (5.3%) patients with prolonged VA-ECMO support developed SCI. The median time from ECMO cannulation to SCI was 7 (range: 6-17) days.There was no evidence of embolic SCI or extended regional hypoxia or hypocarbia. A unilateral, internal iliac artery was covered by the arterial cannula in 6/7 86%) patients, but flow into the internal iliac was demonstrated on imaging in all available patients. The median total flow (ECMO + intrinsic cardiac output) was 8.5 L/min (LPM), and indexed flow was 4.1 LPM/m². The median central venous oxygen saturation was 88%, and intracranial pressure was measured at 30 mmHg in one patient, suggestive of hyperperfusion and spinal cord edema.

CONCLUSIONS

An SCI is a serious complication of extended peripheral VA-ECMO support. Its etiology remains uncertain, but the authors' preliminary data suggested that spinal cord edema from hyperperfusion or venous congestion could contribute.

Platelet Transfusion and In-Hospital Mortality in Veno-Arterial Extracorporeal Membrane Oxygenation Patients

Thrombocytopenia is common during extracorporeal membrane oxygenation (ECMO), and platelets are sometimes transfused to meet arbitrary goals. We performed a retrospective cohort study of veno-arterial (VA) ECMO patients from a single academic medical center and explored the relationship between platelet transfusion and in-hospital mortality using multivariable logistic regression. One hundred eighty-eight VA ECMO patients were included in the study. Ninety-one patients (48.4%) were transfused platelets during ECMO. Patients who received platelet transfusion had more coronary artery disease, lower platelet counts at cannulation, higher predicted mortality, lower nadir platelet counts, more ECMO days, and more red blood cell (RBC) and plasma transfusion. Mortality was 19.6% for patients who received no platelets, 40.8% for patients who received 1-3 platelets, and 78.6% for patients who received 4 or more platelets ( P &lt; 0.001). After controlling for confounding variables including baseline severity of illness, central cannulation, postcardiotomy status, RBC and plasma transfusion, major bleeding, and total ECMO days, transfusion of 4 or more platelets remained associated with in-hospital mortality; OR = 4.68 (95% CI = 1.18-27.28), P = 0.03. Our findings highlight the need for randomized controlled trials that compare different platelet transfusion triggers, so that providers can better understand when platelet transfusion is indicated in VA ECMO patients.

A Comparison between Conventional and Extracorporeal Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-Analysis

There is limited evidence comparing the use of extracorporeal cardiopulmonary resuscitation (ECPR) to CPR in the management of refractory out-of-hospital cardiac arrest (OHCA). We conducted a systematic review and meta-analysis to compare survival and neurologic outcomes associated with ECPR versus CPR in the management of OHCA. We searched PubMed, EMBASE, and Scopus to identify observational studies and randomized controlled trials comparing ECPR and CPR. We used the Newcastle−Ottawa Scale and Cochrane’s risk-of-bias tool to assess studies’ quality. We used random-effects models to compare outcomes between the pooled populations and moderator analysis to identify sources of heterogeneity and perform subgroup analysis. We identified 2088 articles and included 13, with 18,620 patients with OHCA. A total of 16,701 received CPR and 1919 received ECPR. Compared with CPR, ECPR was associated with higher odds of achieving favorable neurologic outcomes at 3 (OR 5, 95% CI 1.90−13.1, p < 0.01) and 6 months (OR 4.44, 95% CI 2.3−8.5, p < 0.01). We did not find a significant survival benefit or impact on neurologic outcomes at hospital discharge or 1 month following arrest. ECPR is a promising but resource-intensive intervention with the potential to improve long-term outcomes among patients with OHCA.

Mortality in cardiogenic shock patients receiving mechanical circulatory support: a network meta-analysis

Objective

Mechanical circulatory support (MCS) devices are widely used for cardiogenic shock (CS). This network meta-analysis aims to evaluate which MCS strategy offers advantages.

Methods

A systemic search of PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials was performed. Studies included double-blind, randomized controlled, and observational trials, with 30-day follow-ups. Paired independent researchers conducted the screening, data extraction, quality assessment, and consistency and heterogeneity assessment.

Results

We included 39 studies (1 report). No significant difference in 30-day mortality was noted between venoarterial extracorporeal membrane oxygenation (VA-ECMO) and VA-ECMO plus Impella, Impella, and medical therapy. According to the surface under the cumulative ranking curve, the optimal ranking of the interventions was surgical venting plus VA-ECMO, medical therapy, VA-ECMO plus Impella, intra-aortic balloon pump (IABP), Impella, Tandem Heart, VA-ECMO, and Impella plus IABP. Regarding in-hospital mortality and 30-day mortality, the forest plot showed low heterogeneity. The results of the node-splitting approach showed that direct and indirect comparisons had a relatively high consistency.

Conclusions

IABP more effectively reduce the incidence of 30-day mortality compared with VA-ECMO and Impella for the treatment of CS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02493-0.

Basics of Extracorporeal Membrane Oxygenation

OVERVIEW

The use of extracorporeal membrane oxygenation (ECMO) is becoming commonplace worldwide in ICUs for the care of patients with respiratory and/or cardiac failure. Understanding the use of ECMO and the management of these complex patients will be vital to current and future clinicians as ECMO use continues to grow.

Extracorporeal Life Support for Cardiac Arrest and Cardiogenic Shock

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

Mechanical 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.

The serial connection of two extracorporeal membrane oxygenators for patient with refractory hypoxemia

A 34-year-old man developed severe hypoxemia and hypercapnia due to acute respiratory distress during ventilator care after surgery with acute intracranial hemorrhage. Severe hypoxemia had not been corrected even with maximum extracorporeal membrane oxygenation (ECMO) flow and full ventilator settings. We applied a novel technique for the serial connection of two veno-venous ECMO circuits for optimal oxygen delivery and CO2 removal and could wean VV ECMO. The use of serial connection of two VV ECMO circuits may be considered worthwhile when severe hypoxemia or hypercapnia are not improved and the use of protective ventilators is not permitted.

Outcomes of Extracorporeal Membrane Oxygenation in Patients With Severe Acute Respiratory Distress Syndrome Caused by COVID-19 Versus Influenza

Background

Extracorporeal membrane oxygenation (ECMO) can be effective for refractory acute respiratory distress syndrome (ARDS) in patients with influenza, but its utility in patients with coronavirus disease 2019 (COVID-19) is uncertain. We compared outcomes of patients with refractory ARDS from COVID-19 and influenza placed on ECMO.

Methods

We conducted a retrospective analysis of 120 patients with refractory ARDS due to COVID-19 or influenza placed on ECMO at 2 referral centers from January 2013 to October 2020. Patient characteristics and clinical outcomes were compared. The primary endpoint was survival to discharge.

Results

Baseline characteristics and comorbidities were similar. During the study period, 53 patients with COVID-19 and 67 patients with influenza were supported. Venovenous ECMO was the predominant initial cannulation strategy in both groups (COVID 92.5% vs influenza 95.5%; P = .5). Survival to hospital discharge was 62.3% (33 of 53 patients) in the COVID-19 group and 64.2% (43 of 67 patients) in the influenza group (P = .8). In patients successfully decannulated, median length of time on ECMO was longer in COVID-19 patients (14 [interquartile range (IQR), 9-30] days vs influenza 10.5 [IQR, 6.8-14.3] days; P = .004). Among patients discharged alive, COVID-19 patients had longer overall length of stay (COVID-19 37 [IQR, 27-62] days vs influenza 13.5 [IQR, 9.3-24] days; P = .007).

Conclusions

In patients with refractory ARDS from COVID-19 or influenza placed on ECMO, there was no significant difference in survival to hospital discharge. In patients surviving to decannulation, the duration of ECMO support and total length of stay were longer in COVID-19 patients.

Transition from Simple V-V to V-A and Hybrid ECMO Configurations in COVID-19 ARDS

In SARS-CoV-2 patients with severe acute respiratory distress syndrome (ARDS), Veno-Venous Extracorporeal Membrane Oxygenation (V-V ECMO) was shown to provide valuable treatment with reasonable survival in large multi-centre investigations. However, in some patients, conversion to modified ECMO support forms may be needed. In this single-centre retrospective registry, all consecutive patients receiving V-V ECMO between 1 March 2020 to 1 May 2021 were included and analysed. The patient cohort was divided into two groups: those who remained on V-V ECMO and those who required conversion to other modalities. Seventy-eight patients were included, with fourteen cases (18%) requiring conversions to veno-arterial (V-A) or hybrid ECMO. The reasons for the ECMO mode configuration change were inadequate drainage (35.7%), inadequate perfusion (14.3%), myocardial infarction (7.1%), hypovolemic shock (14.3%), cardiogenic shock (14.3%) and septic shock (7.1%). In multivariable analysis, the use of dobutamine (p = 0.007) and a shorter ICU duration (p = 0.047) predicted the conversion. The 30-day mortality was higher in converted patients (log-rank p = 0.029). Overall, only 19 patients (24.4%) survived to discharge or lung transplantation. Adverse events were more common after conversion and included renal, cardiovascular and ECMO-circuit complications. Conversion itself was not associated with mortality in the multivariable analysis. In conclusion, as many as 18% of patients undergoing V-V ECMO for COVID-19 ARDS may require conversion to advanced ECMO support.

Uncommon Iatrogenic Devices Seen on Chest Radiographs

Chest radiograph (CXR) is the most common imaging performed for both inpatients and outpatients. With advances in medicine and technology, newer devices/prosthesis are being used in the treatment of cardiothoracic conditions. Some of these are common while others are seen only in a handful of cases, especially in patients being treated or referred from tertiary care centers. It is important to know about these devices, their functionality, and radiographic appearances. Many of these devices also help us in understanding the clinical condition of the patient, as some are only used in unstable patients. Newer methods of life support are now available in intensive care units and these also can be seen on CXRs. In this review, we present various iatrogenic devices that we come across on a CXR and highlight important features to determine their correct placement and potential complications. The review looks at cardiac temporary and permanent pacing devices, cardiac interventional devices used to treat congenital heart disease, newer cardiac monitoring devices, and unusual surgical devices that one may come across on a CXR. We also suggest a stepwise algorithm to assess these devices on a CXR.

ECMO Assistance during Mechanical Ventilation: Effects Induced on Energetic and Haemodynamic Variables

BACKGROUND AND OBJECTIVE

Simulation in cardiovascular medicine may help clinicians understand the important events occurring during mechanical ventilation and circulatory support. During the COVID-19 pandemic, a significant number of patients have required hospital admission to tertiary referral centres for concomitant mechanical ventilation and extracorporeal membrane oxygenation (ECMO). Nevertheless, the management of ventilated patients on circulatory support can be quite challenging. Therefore, we sought to review the management of these patients based on the analysis of haemodynamic and energetic parameters using numerical simulations generated by a software package named CARDIOSIM©.

METHODS

New modules of the systemic circulation and ECMO were implemented in CARDIOSIM© platform. This is a modular software simulator of the cardiovascular system used in research, clinical and e-learning environment. The new structure of the developed modules is based on the concept of lumped (0-D) numerical modelling. Different ECMO configurations have been connected to the cardiovascular network to reproduce Veno-Arterial (VA) and Veno-Venous (VV) ECMO assistance. The advantages and limitations of different ECMO cannulation strategies have been considered. We have used literature data to validate the effects of a combined ventilation and ECMO support strategy.

RESULTS

The results have shown that our simulations reproduced the typical effects induced during mechanical ventilation and ECMO assistance. We focused our attention on ECMO with triple cannulation such as Veno-Ventricular-Arterial (VV-A) and Veno-Atrial-Arterial (VA-A) configurations to improve the hemodynamic and energetic conditions of a virtual patient. Simulations of VV-A and VA-A assistance with and without mechanical ventilation have generated specific effects on cardiac output, coupling of arterial and ventricular elastance for both ventricles, mean pulmonary pressure, external work and pressure volume area.

CONCLUSION

The new modules of the systemic circulation and ECMO support allowed the study of the effects induced by concomitant mechanical ventilation and circulatory support. Based on our clinical experience during the COVID-19 pandemic, numerical simulations may help clinicians with data analysis and treatment optimisation of patients requiring both mechanical ventilation and circulatory support.

Bedside angiography of distal perfusion catheter for veno-arterial extracorporeal membrane oxygenation

BACKGROUND

The aim of this study was to evaluate the ipsilateral lower extremity (ILE) outcomes of patients who underwent bedside angiography via the distal perfusion catheter while on femoral veno-arterial extracorporeal membrane oxygenation (VA ECMO).

METHODS

This is a retrospective analysis of all patients placed on VA ECMO at a single center from January 2017 to December 2019 who underwent bedside angiography via the distal perfusion catheter.

RESULTS

Twenty-four patients underwent bedside angiography via the distal perfusion catheter after being placed on VA ECMO. A vasodilator was directly administered in three patients for suspected spasm. One patient had distal thrombus and underwent thrombectomy and fasciotomy. One patient had a dislodged catheter and underwent thrombectomy, fasciotomy, and replacement of the catheter. One patient had severe ILE ischemia, however was not intervened upon due to critical acuity. Finally, one patient had inadvertent placement in the saphenous vein and had a new catheter placed in the SFA. No patients underwent amputation. Ultimately, 21 patients (87.5%) had no ILE compromise at the end their ECMO course. Survival to decannulation was 66.7% (n = 16).

CONCLUSIONS

Bedside angiography of the distal perfusion catheter is feasible and can be a useful adjunct in informing the need for further intervention to the ILE.

CLASSIFICATIONS

extracorporeal membrane oxygenation, ischemia.

Recommendations From the Professional Advisory Committee on Nursing Practice in the Care of ECMO-Supported Patients

BACKGROUND

By July 2020, the Extracorporeal Life Support Organization had documented more than 133 000 extracorporeal membrane oxygenation (ECMO) implementations, with more than 61 000 implementations in adult patients. No clear policies regarding the authority and responsibility of nursing staff in the treatment of ECMO-supported patients are currently available.

OBJECTIVE

To formulate evidence-based recommendations for nursing care of ECMO-supported patients.

METHODS

The National Head Nurse's office and the Professional Guidelines Department in the Nursing Division of Israel's Ministry of Health formed the Professional Advisory Committee on Nursing Practice in the Care of ECMO-Supported Patients to address concerns regarding the current state of professional nursing practice in the care of these patients. The Professional Advisory Committee brought together 15 senior Israeli ECMO nursing experts who explored the potential of registered nurses in caring for ECMO-supported patients, considered the competencies of nurses treating ECMO-supported patients, discussed training programs and health care policy, and examined nursing outcomes for quality assurance.

RESULTS

The Professional Advisory Committee formulated recommendations regarding the following priority issues: (1) determining boundaries of professional authority and nurses' responsibilities, including designated activities for different professional ranks of registered nurses; (2) providing appropriate content for the training programs offered, such as generic/basic, above-basic, and clinical specialization nursing programs; and (3) defining relevant quality measures for nursing treatment of ECMO-supported patients.

CONCLUSIONS

Introducing international standards would ensure the safety and effectiveness of nursing care for ECMO-supported patients through quality and risk management and establishment of new evidence-based nursing practices.

Determination of cardiovascular dysfunction before initiation of extracorporeal membrane oxygenation in septic shock

Extracorporeal membrane oxygenation (ECMO) is being increasingly used in patients having sepsis-induced cardiovascular dysfunction. We report successful use of venovenous ECMO in septic shock secondary to pneumonia in the presence of severe left ventricular dysfunction. We also discuss the quantitative evaluation of cardiovascular dysfunction, which provides important input in choosing the type of ECMO in septic shock.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-020-01119-4.

Prospective Cohort Study of Population Pharmacokinetics and Pharmacodynamic Target Attainment of Vancomycin in Adults on Extracorporeal Membrane Oxygenation

The aim of this study was to develop a population pharmacokinetics (PK) model for vancomycin and to evaluate its pharmacodynamic target attainment in adults on extracorporeal membrane oxygenation (ECMO). After a single 1,000-mg dose of vancomycin, samples were collected 9 times per patient prospectively. A population PK model was developed using a nonlinear mixed-effect model. The probability of target attainment (PTA) of vancomycin was evaluated for various dosing strategies using Monte Carlo simulation. The ratio of the area under the vancomycin concentration-time curve at steady state over 24 h to the MIC (AUC/MIC ratio) was investigated by applying the vancomycin breakpoint distribution of MICs for methicillin-resistant Staphylococcus aureus A total of 22 adult patients with 194 concentration measurements were included. The population PK was best described by a three-compartment model with a proportional residual error model. Vancomycin clearance and steady-state volume of distribution were 4.01 liters/h (0.0542 liters/h/kg) and 29.6 liters (0.400 liters/kg), respectively. If the treatment target AUC/MIC value was only ≥400, a total daily dose of 3 to 4 g would be optimal (PTA of ≥90%) for patients with normal renal function (estimated glomerular filtration rate [eGFR] = 60 to 120 ml/min/1.73 m²) when the MIC was presumed to be 1 mg/liter. However, AUC/MIC values of 400 to 600 were difficult to attain with any dosing strategy regardless of MIC and eGFR. Thus, it is hard to achieve efficacy and safety targets in patients on ECMO using the population dosing approach with Monte Carlo simulations, and therapeutic drug monitoring should be implemented in these patients.

Venoarterial extracorporeal membrane oxygenation induces early immune alterations

Background

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides heart mechanical support in critically ill patients with cardiogenic shock. Despite important progresses in the management of patients under VA-ECMO, acquired infections remain extremely frequent and increase mortality rate. Since immune dysfunctions have been described in both critically ill patients and after surgery with cardiopulmonary bypass, VA-ECMO initiation may be responsible for immune alterations that may expose patients to nosocomial infections (NI). Therefore, in this prospective study, we aimed to study immune alterations induced within the first days by VA-ECMO initiation.

Methods

We studied immune alterations induced by VA-ECMO initiation using cytometry analysis to characterize immune cell changes and enzyme-linked immunosorbent assay (ELISA) to explore plasma cytokine levels. To analyze specific changes induced by VA-ECMO initiation, nine patients under VA-ECMO (VA-ECMO patients) were compared to nine patients with cardiogenic shock (control patients).

Results

Baseline immune parameters were similar between the two groups. VA-ECMO was associated with a significant increase in circulating immature neutrophils with a significant decrease in C5a receptor expression. Furthermore, we found that VA-ECMO initiation was followed by lymphocyte dysfunction along with myeloid-derived suppressor cells (MDSC) expansion. ELISA analysis revealed that VA-ECMO initiation was followed by an increase in pro-inflammatory cytokines such as IL-6, IL-8 and TNF-α along with IL-10, a highly immunosuppressive cytokine.

Conclusion

VA-ECMO is associated with early immune changes that may be responsible for innate and adaptive immune alterations that could confer an increased risk of infection.

Pharmacokinetics and Monte Carlo Simulation of Meropenem in Critically Ill Adult Patients Receiving Extracorporeal Membrane Oxygenation

Objectives: There have been few clinical studies of ECMO-related alterations of the PK of meropenem and conflicting results were reported. This study investigated the pharmacokinetics (PK) of meropenem in critically ill adult patients receiving extracorporeal membrane oxygenation (ECMO) and used Monte Carlo simulations to determine appropriate dosage regimens. Methods: After a single 0.5 or 1 g dose of meropenem, 7 blood samples were drawn. A population PK model was developed using nonlinear mixed-effects modeling. The probability of target attainment was evaluated using Monte Carlo simulation. The following treatment targets were evaluated: the cumulative percentage of time during which the free drug concentration exceeds the minimum inhibitory concentration of at least 40% (40% fT_>MIC), 100% fT_>MIC, and 100% fT_>4xMIC. Results: Meropenem PK were adequately described by a two-compartment model, in which creatinine clearance and ECMO flow rate were significant covariates of total clearance and central volume of distribution, respectively. The Monte Carlo simulation predicted appropriate meropenem dosage regimens. For a patient with a creatinine clearance of 50-130 ml/min, standard regimen of 1 g q8h by i. v. infusion over 0.5 h was optimal when a MIC was 4 mg/L and a target was 40% fT_>MIC. However, the standard regimen did not attain more aggressive target of 100% fT_>MIC or 100% fT_>4xMIC. Conclusion: The population PK model of meropenem for patients on ECMO was successfully developed with a two-compartment model. ECMO patients exhibit similar PK with patients without ECMO. If more aggressive targets than 40% fT_>MIC are adopted, dose increase may be needed.

Venovenous extracorporeal membrane oxygenation for patients with refractory coronavirus disease 2019 (COVID-19): Multicenter experience of referral hospitals in a large health care system

BACKGROUND

The benefit of extracorporeal membrane oxygenation (ECMO) for patients with severe acute respiratory distress from coronavirus disease 2019 refractory to medical management and lung-protective mechanical ventilation has not been adequately determined.

METHODS

We reviewed the clinical course of 37 patients with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection supported by venovenous ECMO at 4 ECMO referral centers within a large health care system. Patient characteristics, progression of hemodynamics and inflammatory markers, and clinical outcomes were evaluated.

RESULTS

The patients had median age of 51 years (interquartile range, 40-59), and 73% were male. Peak plateau pressures, vasopressor requirements, and arterial partial pressure of carbon dioxide all improved with ECMO support. In our patient population, 24 of 37 patients (64.8%) survived to decannulation and 21 of 37 patients (56.8%) survived to discharge. Among patients discharged alive from the ECMO facility, 12 patients were discharged to a long-term acute care or rehabilitation facility, 2 were transferred back to the referring hospital for ventilatory weaning, and 7 were discharged directly home. For patients who were successfully decannulated, median length of time on ECMO was 17 days (interquartile range, 10-33.5).

CONCLUSIONS

Venovenous ECMO represents a useful therapy for patients with refractory severe acute respiratory distress syndrome from coronavirus disease 2019.

Complete percutaneous decannulation from femoral venoarterial extracorporeal membrane oxygenation

Objectives

To evaluate the clinical outcomes and perioperative complications associated with complete percutaneous decannulation of femoral venoarterial extracorporeal membrane oxygenation (VA-ECMO) with the MANTA closure device.

Methods

This is a retrospective analysis of a single surgeon consecutive series of 14 patients at a single center who underwent decannulation from VA-ECMO, 10 of whom underwent a percutaneous method of femoral cannula removal.

Results

After a mean duration of VA-ECMO support of 7.4 ± 3.8 days, all 10 patients, with arterial cannulas ranging in size from 17 to 21 Fr, underwent percutaneous decannulation with the MANTA closure device, with immediate hemostasis. One patient had acute lower limb ischemia that was recognized intraoperatively and successfully treated with suction embolectomy. Two patients had a pseudoaneurysm at the distal perfusion catheter site recognized on perioperative imaging studies, one resolving with observation and the other necessitating thrombin injection. One patient had a hematoma that resolved with observation.

Conclusions

Percutaneous decannulation from VA-ECMO using the MANTA large-bore vascular closure device is feasible and results in immediate hemostasis with excellent angiographic results.

Successful resuscitation after hyperkalemic cardiac arrest during liver transplantation by converting veno-venous bypass to veno-arterial ECMO

INTRODUCTION

Intraoperative cardiac arrest (ICA) is a feared complication during liver transplantation (LTx), typically occurring during reperfusion. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been used for post-reperfusion cardiac arrest.

CASE REPORT

We present a case of successful resuscitation after hyperkalemic ICA during the pre-anhepatic phase of a second liver transplantation by converting veno-venous bypass (VVB) to VA-ECMO.

DISCUSSION

While this technique has been recommended for ICA during reperfusion, it has never been reported during the pre-anhepatic phase. VA-ECMO can be a lifesaving extension to cardiopulmonary resuscitation for ICA during LTx with beneficial neurological outcome by providing perfusion while the cause of ICA is reversed.

CONCLUSION

Conversion of VVB to VA-ECMO should be considered in all patients who suffer from ICA during LTx with use of VVB. With VVB installed, conversion to VA-ECMO is fast and effective. If VVB is not used, early VA-ECMO should be considered for ICA.

Extracorporeal Cardiopulmonary Resuscitation for Management of Out-of-Hospital Cardiac Arrest in a Patient with Fulminant Myocarditis

A 68-year-old male with a witnessed out-of-hospital cardiac arrest while jogging who was managed with extracorporeal cardiopulmonary resuscitation (ECPR) is presented. The patient was found to be in refractory ventricular fibrillation by emergency medical service personnel and underwent advanced cardiac life support (ACLS) protocol with placement of an automated chest compression device. He was emergently transported to the cardiac catheterization laboratory. Due to refractory ventricular fibrillation, he was placed on venoarterial extracorporeal membranous oxygenation (VA-ECMO). Coronary angiography at that time showed nonobstructive coronary artery disease. Management with VA-ECMO and other supportive measures were continued for 5 days, after which a cardiac magnetic resonance imaging was performed with findings consistent with acute myocarditis. His condition substantially improved, and he was discharged from the hospital with good neurologic and functional status. Fulminant myocarditis is often fatal, but aggressive supportive measures with novel ECPR protocols may result in recovery, as it happened in this case.

Successful difficult airway management with emergent venovenous extracorporeal membrane oxygenation in a patient with severe tracheal deformity: a case report

Background

Difficult airway management is occasionally encountered in the emergency department, and recent studies suggest that extracorporeal membrane oxygenation can be useful in these cases.

Case Presentation

A 74-year-old man was transferred to our hospital due to worsening dyspnea. On arrival, it was found that he was in respiratory distress and was comatose. Arterial blood gas analysis showed severe hypercapnia and respiratory acidosis. Intubation could not be done because he had severe tracheal deformity due to cervical-thoracic kyphosis secondary to vertebral tuberculosis. Therefore, we carried out surgical tracheostomy under venovenous extracorporeal membrane oxygenation. The patient's oxygenation gradually improved, and extracorporeal membrane oxygenation was withdrawn on day 8. He was transferred to another hospital on day 46 and suffered no neurological deficits.

Conclusion

Severe tracheal deformity can result in a difficult airway. Extracorporeal membrane oxygenation is an effective life-saving approach in cases of difficult airway management due to severe tracheal deformity.

Extracorporeal Cardiopulmonary Resuscitation (ECPR) for Out-of-Hospital Cardiac Arrest due to Pulseless Ventricular Tachycardia/Fibrillation

Background

Survival rates for out-of-hospital cardiac arrest are very low and neurologic recovery is poor. Innovative strategies have been developed to improve outcomes. A collaborative extracorporeal cardiopulmonary resuscitation (ECPR) program for out-of-hospital refractory pulseless ventricular tachycardia (VT) and/or ventricular fibrillation (VF) has been developed between The Ohio State University Wexner Medical Center and Columbus Division of Fire.

Methods

From August 15, 2017, to June 1, 2019, there were 86 patients that were evaluated in the field for cardiac arrest in which 42 (49%) had refractory pulseless VT and/or VF resulting from different underlying pathologies and were placed on an automated cardiopulmonary resuscitation device; from these 42 patients, 16 (38%) met final inclusion criteria for ECPR and were placed on extracorporeal membrane oxygenation (ECMO) in the cardiac catheterization laboratory (CCL).

Results

From the 16 patients who underwent ECPR, 4 (25%) survived to hospital discharge with cerebral perfusion category 1 or 2. Survivors tended to be younger (48.0 ± 16.7 vs. 59.3 ± 12.7 years); however, this difference was not statistically significant (p=0.28) likely due to a small number of patients. Overall, 38% of patients underwent percutaneous coronary intervention (PCI). No significant difference was found between survivors and nonsurvivors in emergency medical services dispatch to CCL arrival time, lactate in CCL, coronary artery disease severity, undergoing PCI, and pre-ECMO PaO₂, pH, and hemoglobin. Recovery was seen in different underlying pathologies.

Conclusion

ECPR for out-of-hospital refractory VT/VF cardiac arrest demonstrated encouraging outcomes. Younger patients may have a greater chance of survival, perhaps the need to be more aggressive in this subgroup of patients.

Does Earlier Cannulation With Veno-Venous Extracorporeal Membrane Oxygenation in Adult Patients With Acute Respiratory Distress Syndrome Decrease Duration of Artificial Mechanical Ventilation?

BACKGROUND

Acute respiratory distress syndrome (ARDS) is characterized by an acute, diffuse, inflammatory lung injury, leading to increased alveolar capillary permeability, increased lung weight, and loss of aerated lung tissue (Fan, Brodie, & Slutsky, 2018). Primary treatment for ARDS is artificial mechanical ventilation (AMV) (Wu, Huang, Wu, Wang, & Lin, 2016). Given recent advances in technology, the use of veno-venous extracorporeal membrane oxygenation (VV-ECMO) to treat severe ARDS is growing rapidly (Combes et al., 2014).

OBJECTIVE

This 49-month quantitative, retrospective inpatient EMR chart review compared if cannulation with VV-ECMO up to and including 48 hours of admission and diagnosis in adult patients 30 to 65 years of age diagnosed with ARDS, decreased duration on AMV, as compared to participants who were cannulated after 48 hours of admission and diagnosis with ARDS.

METHODS

A total of 110 participants were identified as receiving VV-ECMO during the study timeframe. Of the 58 participants who met all inclusion criteria, 39 participants were cannulated for VV-ECMO within 48 hours of admission and diagnosis with ARDS, and 19 participants were cannulated with VV-ECMO after 48 hours of admission and diagnosis with ARDS.

RESULTS

Data collected identified no statistically significant (p < 0.579) difference in length of days on AMV between participant groups.

CONCLUSIONS

Further studies are needed to determine if earlier initiation of VV-ECMO in adult patients with ARDS decrease time on AMV.

IMPLICATIONS FOR NURSING

Although the results related to length of time on AMV did not produce statistical significance, the decreased duration of AMV in the participants who were cannulated within 48 hours (21 days vs. 27 days) may support several benefits associated with this participant population including increased knowledge of healthcare providers, decreased lung injury, earlier discharge which decreases hospital and patient cost, ability for patients to communicate sooner, decreased risk of pulmonary infection, decreased length of stay, decreased cost, and improved patient and family satisfaction.

Mechanical assist devices for acute cardiogenic shock

BACKGROUND

Cardiogenic shock (CS) is a state of critical end-organ hypoperfusion due to a primary cardiac disorder. For people with refractory CS despite maximal vasopressors, inotropic support and intra-aortic balloon pump, mortality approaches 100%. Mechanical assist devices provide mechanical circulatory support (MCS) which has the ability to maintain vital organ perfusion, to unload the failing ventricle thus reduce intracardiac filling pressures which reduces pulmonary congestion, myocardial wall stress and myocardial oxygen consumption. This has been hypothesised to allow time for myocardial recovery (bridge to recovery) or allow time to come to a decision as to whether the person is a candidate for a longer-term ventricular assist device (VAD) either as a bridge to heart transplantation or as a destination therapy with a long-term VAD.

OBJECTIVES

To assess whether mechanical assist devices improve survival in people with acute cardiogenic shock.

SEARCH METHODS

We searched CENTRAL, MEDLINE (Ovid), Embase (Ovid) and Web of Science Core Collection in November 2019. In addition, we searched three trials registers in August 2019. We scanned reference lists and contacted experts in the field to obtain further information. There were no language restrictions.

SELECTION CRITERIA

Randomised controlled trials on people with acute CS comparing mechanical assist devices with best current intensive care management, including intra-aortic balloon pump and inotropic support.

DATA COLLECTION AND ANALYSIS

We performed data collection and analysis according to the published protocol. Primary outcomes were survival to discharge, 30 days, 1 year and secondary outcomes included, quality of life, major adverse cardiovascular events (30 days/end of follow-up), dialysis-dependent (30 days/end of follow-up), length of hospital stay and length of intensive care unit stay and major adverse events. We used the five GRADE considerations (study limitations, consistency of effect, imprecision, indirectness, and publication bias) to assess the quality of a body of evidence as it relates to the studies which contribute data to the meta-analyses for the prespecified outcomes Summary statistics for the primary endpoints were risk ratios (RR), hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs).

MAIN RESULTS

The search identified five studies from 4534 original citations reviewed. Two studies included acute CS of all causes randomised to treatment using TandemHeart percutaneous VAD and three studies included people with CS secondary to acute myocardial infarction who were randomised to Impella CP or best medical management. Meta-analysis was performed only to assess the 30-day survival as there were insufficient data to perform any further meta-analyses. The results from the five studies with 162 participants showed mechanical assist devices may have little or no effect on 30-day survival (RR of 1.01 95% CI 0.76 to 1.35) but the evidence is very uncertain. Complications such as sepsis, thromboembolic phenomena, bleeding and major adverse cardiovascular events were not infrequent in both the MAD and control group across the studies, but these could not be pooled due to inconsistencies in adverse event definitions and reporting. We identified four randomised control trials assessing mechanical assist devices in acute CS that are currently ongoing.

AUTHORS' CONCLUSIONS

There is no evidence from this review of a benefit from MCS in improving survival for people with acute CS. Further use of the technology, risk stratification and optimising the use protocols have been highlighted as potential reasons for lack of benefit and are being addressed in the current ongoing clinical trials.

A novel veno-arteriovenous extracorporeal membrane oxygenation with double pump for the treatment of Harlequin syndrome

Objectives:

The Harlequin syndrome is a complication observed in patients receiving peripheral venoarterial extracorporeal membrane oxygenation. This condition is defined as a critical variation in the oxygen saturation between the upper and the lower part of the body deriving from a poor lung function.

Methods:

Between July 2018 and November 2019, a total of 60 patients (42 men and 18 women; mean age 57.4 ± 10.0 years; range = 28-71 years) underwent peripheral venoarterial extracorporeal membrane oxygenation in our center. Harlequin syndrome was identified in eight cases (six men and two women; 13.3%) of the 60 venoarterial extracorporeal membrane oxygenation–supported patients. As a result of the Harlequin syndrome, all these patients required conversion to veno-arteriovenous extracorporeal membrane oxygenation. Control and monitoring of the blood flows of the return cannulae were performed using two centrifugal pumps, one for each inlet line, according to the patient requirements to achieve optimum hemodynamic and oxygenation.

Results:

Mean duration of veno-arteriovenous extracorporeal membrane oxygenation support was 5.3 ± 1.4 days. Seven patients (87.5%) were switched to venovenous extracorporeal membrane oxygenation, and after 13.5 ± 2.7 days, those patients were totally weaned from extracorporeal membrane oxygenation support. One patient (12.5%) had an improvement in the pulmonary function, but the cardiac function was poor. This patient was switched to venoarterial extracorporeal membrane oxygenation, and after 10 days, the patient was completely weaned from extracorporeal membrane oxygenation support.

Conclusion:

The use of a secondary centrifugal pump to manage the blood flow directed to the internal jugular vein, in the veno-arteriovenous extracorporeal membrane oxygenation setup, allows the reduction in the risk of blood clot formation, clotting factor consumption, and pulmonary embolism when compared to the use of an external clamp.

Pearls for addressing traumatic cranio-cervical instability in a patient on extracorporeal membrane oxygenation (ECMO)

BACKGROUND

Concurrent craniocervical dissociation in a multi-trauma patient requiring venous-venous extracorporeal membranous oxygenation (ECMO) poses significant challenges in its management.

PURPOSE

This article describes the nuances of the surgical decision-making in a complex case of a polytrauma patient with craniocervical dissociation who required concurrent ECMO.

STUDY DESIGN/ SETTING

Case report and literature review.

METHODS

The authors describe a complex case of a patient with craniocervical dissociation requiring ECMO and who was managed surgically in a level 1 trauma centre in Victoria, Australia after sudden neurological deterioration whilst in a halo-vest. A literature search using appropriate medical subject headings and keywords was performed to identify published cases of craniocervical dissociation in patients requiring concurrent ECMO.

RESULTS

Literature search yielded twenty-seven articles, with only two relevant articles identified for full text review. Only one article was found to be relevant, which however did not provide detailed discussion on surgical aspect of the pathology.

CONCLUSION

To the authors' knowledge, this is the first report of management of craniocervical dissociation in a patient requiring ECMO due to polytrauma focused on the nuances of the complex surgical decision-making which is required for proper management of such critical condition.

Intraoperative Extracorporeal Membrane Oxygenation in Thoracic Surgery

Evidence supporting the utilization of extracorporeal membrane oxygenation (ECMO) outside the intensive care unit is limited. We present 3 clinical situations where intraoperative ECMO was beneficial. Peripheral venovenous cannulation was used to augment tracheal surgery in 2 patients, and in 1 patient who did not tolerate lung isolation. After surgery, all patients were de-cannulated and there were no complications observed due to ECMO. Use of this technology can greatly facilitate thoracic surgical procedures with low risk. ECMO should be considered when performing tracheal surgery and in situations of poor tolerance to lung isolation.

Myocardial perfusion and cardiac dimensions during extracorporeal membrane oxygenation-supported circulation in a porcine model of critical post-cardiotomy failure

Introduction:

Venoarterial extracorporeal membrane oxygenation is widely used as mechanical circulatory support for severe heart failure. A major concern with this treatment modality is left ventricular distension due to inability to overcome the afterload created by the extracorporeal membrane oxygenation circuit. The present porcine study evaluates coronary circulation, myocardial perfusion and ventricular distension during venoarterial extracorporeal membrane oxygenation.

Methods:

Ten anesthetized open-chest pigs were cannulated and put on cardiopulmonary bypass. Heart failure was achieved by 90 minutes of aortic cross-clamping with insufficient cardioplegic protection. After declamping, the animals were supported by venoarterial extracorporeal membrane oxygenation for 3 hours. Continuous haemodynamic measurements were performed at baseline, during cardiopulmonary bypass/aortic cross-clamping and during venoarterial extracorporeal membrane oxygenation. Fluorescent microsphere injections at baseline and after 1, 2 and 3 hours on venoarterial extracorporeal membrane oxygenation evaluated myocardial perfusion. Left ventricular function and distension were assessed by epicardial echocardiography.

Results:

The myocardial injury caused by 90 minutes of ischaemia resulted in a poorly contracting myocardium, necessitating venoarterial extracorporeal membrane oxygenation in all animals. The circulatory support maintained the mean arterial blood pressure within a satisfactory range. A hyperaemic left anterior descending coronary artery flow while on extracorporeal membrane oxygenation was observed compared to baseline. Myocardial tissue perfusion measured by microspheres was low, especially in the subendocardium. Echocardiography revealed myocardial tissue oedema, a virtually empty left ventricle, and a left ventricular output that remained negligible throughout the extracorporeal membrane oxygenation run.

Conclusion:

Coronary artery blood flow is maintained during venoarterial extracorporeal membrane oxygenation after cardiopulmonary bypass and cardioplegic arrest despite severely affected performance of the left ventricle. Myocardial perfusion decreases, however, presumably due to rapid development of myocardial tissue oedema.

Determining the impacts of venoarterial extracorporeal membrane oxygenation on cerebral oxygenation using a one-dimensional blood flow simulator

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is a mechanical system that provides rapid and short-term support for patients with cardiac failure. In many patients, pulmonary function is also impaired, resulting in poorly-oxygenated cardiac outflow competing against well-oxygenated VA-ECMO outflow, a condition known as North-South syndrome. North-South syndrome is a primary concern because of its potential to cause cerebral hypoxia, which has a critical influence on neurological complications often seen in this patient population. In order to reduce ischemic neurological complications, it is important to understand how clinical decisions regarding VA-ECMO parameters influence blood oxygenation. Here, we studied the impacts of flow rate and cannulation site on oxygenation using a one-dimensional (1D) model to simulate blood flow. Our model was initially tested by comparing blood flow results to those observed from experimental work in VA-ECMO patients. The 1D model was combined with a two-phase flow model to simulate oxygenation. Additionally, the influence of various other clinician-tunable parameters on oxygenation in the common carotid arteries (CCAs) were tested, including, blood viscosity, cannula position within the insertion artery, heart rate, and systemic vascular resistance (SVR), as well as geometrical changes such as arterial radius and length. Our results indicated that blood oxygenation to the brain strongly depended on the cannula insertion site and the VA-ECMO flow rate with a weaker but potentially significant dependence on arterial radius. During femoral cannulation, VA-ECMO flow rates greater than ~4.9L/min were needed to perfuse the CCAs. However, axillary and central cannulation began to perfuse the CCAs at significantly lower flow (~1L/min). These results may help explain the incidence of cerebral hypoxia in this patient population and the common need to change cannulation strategies during treatment to address this clinical problem. While this work describes patient-averaged results, determining these relationships between VA-ECMO parameters and cerebral hypoxia is an important step towards future work to develop patient-specific models that clinicians can use to improve outcomes.

Sutureless Closure of Arterial Cannulation Sites

OBJECTIVE

Percutaneous femoral cannulation for venoarterial extracorporeal membrane oxygenation (ECMO) is commonly performed but percutaneous removal of arterial cannulas has not been broadly accepted. We hypothesized that a system that allows endovascular access to ECMO circuits along with the MANTA^® large-bore vascular closure device could be used to successfully close arterial ECMO cannulation sites in a large animal model.

METHODS

Yorkshire swine (40 to 60 kg, n = 2) were used for this study. In the first swine, the infrarenal abdominal aorta was exposed. The aorta was cannulated once using a 15 Fr cannula and twice with a 19 Fr arterial cannula. A novel adaptor system that facilitates endovascular access to ECMO circuits was connected, and a 0.035″ Benston wire was placed through the adaptor and guided into the aorta. The cannula was removed over the wire and manual pressure was applied. The MANTA^® sheath was inserted over the wire followed by the closure unit and was deployed. The process was repeated at 2 separate sites. A similar experiment was performed in a second swine, but through a median sternotomy to cannulate the ascending aorta.

RESULTS

Good hemostasis was achieved at all cannulation sites. Angiography demonstrated unobstructed flow across all closure sites with no evidence of extravasation.

CONCLUSIONS

The data presented here support the use of the MANTA^® vascular closure device for the closure of arterial cannulation sites following ECMO decannulation and demonstrates utility of a novel adaptor system for establishing endovascular access in this context.

Venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock-A six-year service evaluation

Only a small number of English hospitals provide postcardiotomy venoarterial extracorporeal membrane oxygenation (VA-ECMO) and there are doubts about its efficacy and safety. The aim of this service evaluation was to determine local survival rates and report on patient demographics. This was a retrospective service evaluation of prospectively recorded routine clinical data from a tertiary cardiothoracic center in the United Kingdom offering services including cardiac and thoracic surgery, heart and lung transplantation, venovenous extracorporeal membrane oxygenation (VV-ECMO) for respiratory failure, and all types of mechanical circulatory support. In six years, 39 patients were supported with VA-ECMO for refractory postcardiotomy cardiogenic shock (PCCS). We analyzed survival data and looked for associations between survival rates and patient characteristics. The intervention was venoarterial-ECMO in patients with PCCS either following weaning from cardiopulmonary bypass or following a trial of inotropes and intra-aortic balloon counterpulsation on the intensive care unit. 30-day, hospital discharge, 1-year and 2-year survivals were 51.3%, 41%, 37.5%, and 38.5%, respectively. The median (IQR [range]) duration of support was 6 (4-9 [1-35]) days. Nonsurvival was associated with advanced age, shorter intensive care length of stay, and the requirement for postoperative hemofiltration. Reasonable survival rates can be achieved in selected patients who may have been expected to have a worse mortality without VA-ECMO. We suggest postoperative VA-ECMO should be available to all patients undergoing cardiac surgery be it in their own center or through an established pathway to a specialist center.

Effect of extracorporeal membrane oxygenation transport on short- and long-term survival in patients with acute respiratory distress syndrome

Venovenous extracorporeal membrane oxygenation (ECMO) has emerged as an important tool in the treatment of acute respiratory distress syndrome (ARDS). The creation of portable ECMO circuits and pumps has supported the development of interfacility ECMO programs. Prior studies have demonstrated that ECMO transport is safe; however, long-term outcomes for these patients remain unknown. Retrospective analysis of our 5-year experience identified 58 patients transported on ECMO and 82 patients cannulated at our institution. When short-term (30 days) and long-term (1 year) outcomes were compared between these cohorts, there was no statistically significant difference in survival (P = 0.44 and 0.49). There were no deaths related to transport, and the rate of ECMO-related complications was similar between the groups. With established patient safety and similar long-term survival, ECMO transport is a feasible solution to provide access to ECMO for all communities.

Simultaneous quantitative LC-MS method of ketamine, midazolam and their metabolites (dehydronorketamine, norketamine and 1hydroxymidazolam) for its application in patients on extracorporeal membrane oxygenation (ECMO) therapy

Ketamine (Ket) and midazolam (MDZ) are commonly administered drugs in the intensive care setting for analgesia and sedation. Ket and MDZ are metabolized to dehydro-norketamine (DHNK), nor-ketamine (NK) and 1-hydroxy midazolam (1HMDZ). Limited studies evaluating their pharmacokinetics exists in patients on extracorporeal membrane oxygenation (ECMO) therapy. Therefore, we developed a quantitative, high-performance liquid chromatography-mass spectrometry (with single ion monitoring) method to simultaneously detect Ket, MDZ and their (DHNK, NK and 1HMDZ) metabolites in human plasma. Considerable sensitivity was obtained for the analytes using a C₁₈ HILIC column operated by a high-performance liquid chromatography system coupled with a Thermo Exactive Orbitrap mass spectrometer. Calibration curves were developed for analyte molecules (n = 5) in the presence of carbamazepine (CBZ) as an internal standard. The lower limits of quantitation (LLOQ) for Ket and MDZ were 20 and 10 ng/mL, respectively with the LLOQ for DHNK, NK and 1HMDZ at 470, 320 and 150 ng/ml. Moreover, the percent coefficient of variance and precision for inter- and intra-day runs were within the standards set forth by the ICH and FDA guidelines. This method is sensitive and has been successfully applied to an ongoing pharmacokinetic study in patients on ECMO therapy.