Vascular access for extracorporeal life support: tips and tricks

Extracorporal Membrane Oxygenation in Massive Pulmonary Embolism

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Changes in Therapy and Outcome of Patients Requiring Veno-Venous Extracorporeal Membrane Oxygenation for COVID-19

BACKGROUND

 Coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome requiring veno-venous extracorporeal membrane oxygenation (vv-ECMO) is related with poor outcome, especially in Germany. We aimed to analyze whether changes in vv-ECMO therapy during the pandemic were observed and lead to changes in the outcome of vv-ECMO patients.

METHODS

 All patients undergoing vv-ECMO support for COVID-19 between 2020 and 2021 in a single center (n = 75) were retrospectively analyzed. Weaning from vv-ECMO and in-hospital mortality were defined as primary and peri-interventional adverse events as secondary endpoints of the study.

RESULTS

 During the study period, four infective waves were observed in Germany. Patients were assigned correspondingly to four study groups: ECMO implantation between March 2020 and September 2020: first wave (n = 11); October 2020 to February 2021: second wave (n = 23); March 2021 to July 2021: third wave (n = 25); and August 2021 to December 2021: fourth wave (n = 20). Preferred cannulation technique changed within the second wave from femoro-femoral to femoro-jugular access (p < 0.01) and awake ECMO was implemented. Mean ECMO run time increased by more than 300% from 10.9 ± 9.6 (first wave) to 44.9 ± 47.0 days (fourth wave). Weaning of patients was achieved in less than 20% in the first wave but increased to approximately 40% since the second one. Furthermore, we observed a continuous numerically decrease of in-hospital mortality from 81.8 to 57.9% (p = 0.61).

CONCLUSION

 Preference for femoro-jugular cannulation and awake ECMO combined with preexisting expertise and patient selection are considered to be associated with increased duration of ECMO support and numerically improved ECMO weaning and in-hospital mortality.

Intraoperative Extracorporeal Support during Lung Transplantation: Not Just for the High-Risk Patient

The use of intraoperative mechanical support during lung transplantation has traditionally been a controversial topic. Trends for intraoperative mechanical support strategies swing like a pendulum. Historically, cardiopulmonary bypass (CPB) was the modality of choice during transplantation. It provides full hemodynamic support including oxygenation and decarboxylation. Surgical exposure is improved by permitting the drainage of the heart and provides more permissive retraction. CPBs contain drainage reservoirs with hand-held pump suction catheters promoting blood conservation through collection and re-circulation. But CPB has its disadvantages. It is known to cause systemic inflammation and coagulopathy. CPB requires high doses of heparinization, which increases bleeding risks. As transplantation progressed, off-pump transplantation began to trend as a preferable option. ECMO, however, has many of the benefits of CPB with less of the risk. Outcomes were improved with ECMO compared to CPB. CPB has a higher blood transfusion requirement, a higher need for post-operative ECMO support, a higher re-intubation rate, high rates of kidney injury and need for hemodialysis, longer ICU stays, higher incidences of PGD grade 3, as well as overall in-hospital mortality when compared with ECMO use. The focus now shifts to using intraoperative mechanical support to protect the graft, helping to reduce ischemia-reperfusion injury and allowing for lung protective ventilator settings. Studies show that the routine use of ECMO during transplantation decreases the rate of primary graft dysfunction and many adverse outcomes including ventilator time, need for tracheostomy, renal failure, post-operative ECMO requirements, and others. As intraoperative planned ECMO is considered a safe and effective approach, with improved survival and better overall outcomes compared to both unplanned ECMO implementation and off-pump transplantation, its routine use should be taken into consideration as standard protocol.

Extracorporeal life support use in limited lung function: a narrative review

Background and Objective

In thoracic surgery, different modalities of extracorporeal life support (ECLS) can be used for cardiorespiratory support in complex scenarios. Decades of learning in clinical practice and physiology associated with technological development led to a great variety of ECLS technologies available. Thoracic surgery procedures with difficult or impossible single lung ventilation may still be performed using different ECLS modalities. The aim of this review is to describe the use of ECLS, with its different modalities, as a solution to perform complex surgeries in a patient with difficult or impossible single lung ventilation.

Methods

A literature review was conducted using the terms "extracorporeal life support pulmonary resection" and "extracorporeal life support thoracic surgery", and articles were selected according to defined criteria.

Key Content and Findings

To support lung function during thoracic surgery, the most efficient and popular variety of ECLS is venovenous extracorporeal membrane oxygenation. Lung resection on a single lung after pneumonectomy, surgery in a patient with severe hypercapnia and/or low respiratory reserve, carinal and airway surgery, and severe thoracic trauma are the main examples of situations where ECLS may be the solution to provide a safe surgical environment in patients who cannot tolerate single lung ventilation. Multidisciplinarity, selection of patients and careful surgical planning are cornerstones in defining the situations that may benefit from ECLS support.

Conclusions

Knowledge on techniques of ECLS are essential for every thoracic surgeon. Although rarely used, these techniques of cardiorespiratory support should be considered when planning complex cases with difficulties in ventilation and emergent situations.

Outcome of Emergency Pulmonary Lobectomy under ECMO Support in Patients with COVID-19

BACKGROUND

 Not much is known about the results of nonelective anatomical lung resections in coronavirus disease 2019 (COVID-19) patients put on extracorporeal membrane oxygenation (ECMO). The aim of this study was to analyze the outcome of lobectomy under ECMO support in patients with acute respiratory failure due to severe COVID-19.

METHODS

 All COVID-19 patients undergoing anatomical lung resection with ECMO support at a German university hospital were included into a prospective database. Study period was April 1, 2020, to April 30, 2021 (first, second, and third waves in Germany).

RESULTS

 A total of nine patients (median age 61 years, interquartile range 10 years) were included. There was virtually no preexisting comorbidity (median Charlson score of comorbidity 0.2). The mean interval between first positive COVID-19 test and surgery was 21.9 days. Clinical symptoms at the time of surgery were sepsis (nine of nine), respiratory failure (nine of nine), acute renal failure (five of nine), pleural empyema (five of nine), lung artery embolism (four of nine), and pneumothorax (two of nine). Mean intensive care unit (ICU) and ECMO days before surgery were 15.4 and 6, respectively. Indications for surgery were bacterial superinfection with lung abscess formation and progressive septic shock (seven of nine) and abscess formation with massive pulmonary hemorrhage into the abscess cavity (two of nine). All patients were under venovenous ECMO with femoral-jugular configuration. Operative procedures were lobectomy (eight) and pneumonectomy (one). Weaning from ECMO was successful in four of nine. In-hospital mortality was five of nine. Mean total ECMO days were 10.3 ± 6.2 and mean total ICU days were 27.7 ± 9.9. Mean length of stay was 28.7 ± 8.8 days.

CONCLUSION

 Emergency surgery under ECMO support seems to open up a perspective for surgical source control in COVID-19 patients with bacterial superinfection and localized pulmonary abscess.

Transaortic Placement of Percutaneous Mechanical Support Device via Partial Sternotomy: Feasible Option for Unsuitable Axillary Artery Access

Acute decompensated refractory cardiogenic shock is an emergency in which the prompt instauration of mechanical circulatory support improves outcomes. The typical, initial approach for device delivery is via femoral vessels due to easy access and safety. If longer support is needed, the femoral access will severely impair the patient’s mobility and can also limit the amount of support given as the new-generation devices are too large for direct arterial insertion. Upper-body arterial conduits (UBACs) are used for the delivery of larger, percutaneous ventricular assist devices (pVADs). The Impella 5.5 (Abiomed, Danvers, MA, USA) is a pVAD that can be deployed through a UBAC by either axillary/subclavian access or a transaortic approach. The latter approach is typically used in cases of postcardiotomy shock, in which the ascending aorta is already exposed through a full sternotomy. However, in some cases, the axillary artery is not suitable due to size (<6 mm in diameter), and a smaller pVAD is delivered into the heart. To avoid providing suboptimal support, we present an alternative, minimally invasive approach in which the larger device is delivered through the ascending aorta. This article summarizes the details of this approach through a mini upper partial sternotomy and reviews the relevant technical considerations.

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.

Intraoperative support during lung transplantation

The role of intraoperative mechanical support during lung transplantation (LTx) is essential to provide a safe hemodynamic and ventilatory status during critical intraoperative events. This hemodynamic and ventilatory stability is vital to minimize the odds of suboptimal outcomes, especially considering that, due to the scarcity of donors and the fact that more and more patients with significant comorbidities are being considered for this therapy, a more aggressive approach is often needed by the transplant centers. Hence, the attenuation of any potential injury that can happen during this complex event is paramount. While a thorough assessment of the donor and optimization of postoperative care is pursued, certainly protective intraoperative management would also contribute to better outcomes. Understanding each patient’s underlying anatomy and cardiopulmonary physiology, associated with awareness of critical events during a complicated procedure like LTx, is essential for a precise indication and safe use of support. Cardiopulmonary bypass (CPB) and veno-arterial extracorporeal membrane oxygenation (VA ECMO) have been the most common approaches used, with the latter gaining popularity more recently and we have used VA ECMO exclusively for the last decade. New technologies certainly contributed to more liberal use of VA ECMO intraoperatively, enabling a protecting and physiologic environment for the newly implanted grafts. In this setting, potential prophylactic use for lung protection during a critical period is also considered.

SEDAR/SECCE ECMO management consensus document

ECMO is an extracorporeal cardiorespiratory support system whose use has been increased in the last decade. Respiratory failure, postcardiotomy shock, and lung or heart primary graft failure may require the use of cardiorespiratory mechanical assistance. In this scenario perioperative medical and surgical management is crucial. Despite the evolution of technology in the area of extracorporeal support, morbidity and mortality of these patients continues to be high, and therefore the indication as well as the ECMO removal should be established within a multidisciplinary team with expertise in the area. This consensus document aims to unify medical knowledge and provides recommendations based on both the recent bibliography and the main national ECMO implantation centres experience with the goal of improving comprehensive patient care.

Acute Kidney Injury During Extracorporeal Membrane Oxygenation: VA ECMO Versus VV ECMO

PURPOSE

Acute kidney injury (AKI) has been reported to be one of the most common complications in patients receiving extracorporeal membrane oxygenation (ECMO), yet variations in AKI between different types of ECMO remain unclear. This meta-analysis systematically compares AKI/severe AKI in adult patients requiring different types of ECMO.

METHODS

Two authors independently performed a literature search using PubMed, Web of Science, and Embase, encompassing publications up until April 20, 2020 (inclusive). The number of AKI patients, including patients who required/did not require renal replacement therapy (RRT), and deceased patients with AKI/severe AKI, who received different types of ECMO were collated and analyzed using STATA.

RESULTS

The results indicated that there were no significant differences in the risk of AKI/severe AKI among different types of ECMO. However, the presence of AKI and severe AKI during veno-arterial (VA) ECMO was more strongly associated with mortality.

CONCLUSIONS

Although mortality rates related to AKI/severe AKI during VV ECMO are high, the occurrence of AKI/severe AKI during VA ECMO should be given greater attention, as these instances are considered strong indicators of patient deterioration and even death. Additional studies are needed to corroborate these findings.

Perioperative, protective use of extracorporeal membrane oxygenation in complex thoracic surgery

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is increasingly used in patients undergoing complex thoracic surgical procedures. However, studies reporting the clinical outcomes of these patients are limited to case reports, without real consensus. Our aim was to evaluate the perioperative use of ECMO as respiratory and/or circulatory support in thoracic surgery: indications, benefits, and perioperative management.

METHODS

Between May 2013 and December 2018, we reviewed the clinical data of 15 patients (11 males and 4 females; mean age: 47 years old; range, 25-73 years) undergoing ECMO-assisted thoracic surgery in our hospital.

RESULTS

Of the 15 patients, 10 cases received peripheral veno-arterial (VA) ECMO and five cases received veno-venous (VV) ECMO. Indications for ECMO were pulmonary transplantation with hard-to-maintain oxygenation (n = 5), traumatic main bronchial rupture (n = 2), traumatic lung injury (n = 1), airway tumor leading to severe airway stenosis (n = 2), huge thoracic mass infiltrated vena cava (n = 5). The ECMO duration was 1-51 hours. All patients were successfully extubated and weaned from ECMO postoperatively. The main complications were hemorrhage (26.7%), infection (33.3%), acute hepatic dysfunction (33.3%), and venous thrombosis (26.7%). There was only one hospital death and postoperative one-year survival rate was 86%.

CONCLUSION

Our experience indicates that ECMO is a feasible method for complex trachea-bronchial surgery, huge thoracic mass excision and lung transplantation, and the ECMO-related risks may be justified. With further accumulation of experience with ECMO, a more sophisticated protocol for management of critical airway or heart failure problems in thoracic surgeries can be derived.

Perioperative circulatory support for lung transplantation

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) has recently replaced cardiopulmonary bypass (CPB) as the preferred option for providing circulatory support during lung transplantation. This review aimed to summarize the previous data and to address the relative use of ECMO and CPB during lung transplantation.

METHODS

The database was searched in PubMed (Medline) using the following keywords: lung transplantation, extracorporeal membrane oxygenation, and cardiopulmonary bypass, for all relevant reports which were written in English and were published between 2000 and 2020.

REVIEW

Several reports have revealed that intraoperative use of ECMO is associated with lower blood product transfusion requirements, shorter ventilator support, and shorter length of hospital stay. During recent years, preoperative ECMO has also been used with favorable outcomes as a bridge to lung transplantation in critically ill patients.

CONCLUSIONS

The use of ECMO during lung transplantation seems to reduce postoperative complications and improve short-term outcomes, relative to CPB. However, additional data should be collected through large multicenter randomized controlled trials. Furthermore, preoperative ECMO as a bridge to lung transplantation appears to provide favorable outcomes, although additional data are also needed from experienced transplant centers.

Intraoperative care of elderly patients with COVID-19 undergoing double lung transplantation: Two case reports

BACKGROUND

Lung transplantation is considered an effective method for treating patients with end-stage coronavirus disease 2019 (COVID-19). The nurses play a pivotal role in lung transplantation for COVID-19 patients.

CASE SUMMARY

Two elderly patients were admitted to the emergency department due to cough, and the nucleic acid test was positive. The patients were preliminarily diagnosed with COVID-19. The chest computed tomography scan revealed massive lung consolidation, and the patients did not improve after treatment with antiviral drugs, glucocorticoids, antibiotics, and other drugs. Under the support of pure oxygen in extracorporeal membrane oxygenation, the patients’ oxygen levels were still poor, indicating that they were in the terminal stage of viral pneumonia. The patients underwent double-lung transplantation and received intraoperative care. The extracorporeal membrane oxygenation device was removed within a week of the surgical procedure, and the respiratory circulation of the patients were stabilized.

CONCLUSION

High-quality care for COVID-19 patients undergoing lung transplantation ensures patient safety during operation while protecting the safety of the medical staff.

Vascular access in ECMO

In critically ill patients, deserving extracorporeal membrane oxygenation (ECMO), choosing the right pattern of cannulation such as veno-venous (VV), veno-arterial (VA), veno-veno-arterial (VVA), and central; selecting the appropriate size cannulae; and good cannulation techniques are all pre-requisites for the successful outcome of ECMO. We are describing the selection criteria for choosing appropriate size cannulae, cannulation configurations, available cannulae, and possible complications. A brief note on anticoagulation was added.

Pharmacokinetics of micafungin in patients treated with extracorporeal membrane oxygenation: an observational prospective study

Objective

To determine micafungin plasma levels and pharmacokinetic behavior in patients treated with extracorporeal membrane oxygenation.

Methods

The samples were taken through an access point before and after the membrane in two tertiary hospitals in Spain. The times for the calculation of pharmacokinetic curves were before the administration of the drug and 1, 3, 5, 8, 18 and 24 hours after the beginning of the infusion on days one and four. The area under the curve, drug clearance, volume of distribution and plasma half-life time with a noncompartmental pharmacokinetic data analysis were calculated.

Results

The pharmacokinetics of the values analyzed on the first and fourth day of treatment did not show any concentration difference between the samples taken before the membrane (Cin) and those taken after the membrane (Cout), and the pharmacokinetic behavior was similar with different organ failures. The area under the curve (AUC) before the membrane on day 1 was 62.1 (95%CI 52.8 - 73.4) and the AUC after the membrane on this day was 63.4 (95%CI 52.4 - 76.7), p = 0.625. The AUC before the membrane on day 4 was 102.4 (95%CI 84.7 - 142.8) and the AUC was 100.9 (95%CI 78.2 - 138.8), p = 0.843.

Conclusion

The pharmacokinetic parameters of micafungin were not significantly altered.

Long-Term Venovenous Connection for Extracorporeal Carbon Dioxide Removal (ECCO2R)-Numerical Investigation of the Connection to the Common Iliac Veins

Purpose

Currently used cannulae for extracorporeal carbon dioxide removal (ECCO₂R) are associated with complications such as thrombosis and distal limb ischemia, especially for long-term use. We hypothesize that the risk of these complications is reducible by attaching hemodynamically optimized grafts to the patient’s vessels. In this study, as a first step towards a long-term stable ECCO₂R connection, we investigated the feasibility of a venovenous connection to the common iliac veins. To ensure its applicability, the drainage of reinfused blood (recirculation) and high wall shear stress (WSS) must be avoided.

Methods

A reference model was selected for computational fluid dynamics, on the basis of the analysis of imaging data. Initially, a sensitivity analysis regarding recirculation was conducted using as variables: blood flow, the distance of drainage and return to the iliocaval junction, as well as the diameter and position of the grafts. Subsequently, the connection was optimized regarding recirculation and the WSS was evaluated. We validated the simulations in a silicone model traversed by dyed fluid.

Results

The simulations were in good agreement with the validation measurements (mean deviation 1.64%). The recirculation ranged from 32.1 to 0%. The maximum WSS did not exceed 5.57 Pa. The position and diameter of the return graft show the highest influence on recirculation. A correlation was ascertained between recirculation and WSS. Overall, an inflow jet directed at a vessel wall entails not only high WSS, but also a flow separation and thereby an increased recirculation. Therefore, return grafts aligned to the vena cava are crucial.

Conclusion

In conclusion, a connection without recirculation could be feasible and therefore provides a promising option for a long-term ECCO₂R connection.

In Vivo 5 Day Animal Studies of a Compact, Wearable Pumping Artificial Lung

Recent studies show improved outcomes in ambulated lung failure patients. Ambulation still remains a challenge in these patients. This necessitates development of more compact and less cumbersome respiratory support specifically designed to be wearable. The Paracorporeal Ambulatory Assist Lung (PAAL) is being designed for providing ambulatory support in lung failure patients during bridge to transplant or recovery. We previously published in vitro and acute in vivo results of the PAAL. This study further evaluates the PAAL for 5 days. Five-day in vivo studies with the PAAL were conducted in 50-60 kg sheep after heparinization (activated clotting time range: 190-250 s) and cannulation with a 27 Fr. Avalon Elite dual-lumen cannula. The animals were able to move freely in a stanchion while device flow, resistance, and hemodynamics were recorded hourly. Oxygenation and hemolysis were measured daily. Platelet activation, blood chemistry, and comprehensive blood counts are reported for preoperatively, on POD 0, and POD 5. Three animals survived for 5 days. No study termination resulted from device failure. One animal was terminated on POD 0 and one animal was terminated at POD 3. The device was operated between 1.93 and 2.15 L/min. Blood left the device 100% oxygenated. Plasma-free hemoglobin ranged 10.8-14.5 mg/dl. CD62-P expression was under 10%. Minimal thrombus was seen in devices at explant. Chronic use of the PAAL in awake sheep is promising based on our study. There were no device-related complications over the study course. This study represents the next step in our pathway to eventual clinical translation.

Extracorporeal membrane oxygenation: a literature review

Extracorporeal membrane oxygenation is a modality of extracorporeal life support that allows for temporary support in pulmonary and/or cardiac failure refractory to conventional therapy. Since the first descriptions of extracorporeal membrane oxygenation, significant improvements have occurred in the device and the management of patients and, consequently, in the outcomes of critically ill patients during extracorporeal membrane oxygenation. Many important studies about the use of extracorporeal membrane oxygenation in patients with acute respiratory distress syndrome refractory to conventional clinical support, under in-hospital cardiac arrest and with cardiogenic refractory shock have been published in recent years. The objective of this literature review is to present the theoretical and practical aspects of extracorporeal membrane oxygenation support for respiratory and/or cardiac functions in critically ill patients.

Cannula position and Bernoulli effect contribute to leg malperfusion during extracorporeal life support with femoral arterial cannulation-an in silico simulation study†

OBJECTIVES

Limb ischaemia during extracorporeal life support (ECLS) using femoral artery cannulation is frequently observed even in patients with regular vessel diameters and without peripheral arterial occlusive disease. We investigated underlying pathomechanisms using a virtual fluid-mechanical simulation of the human circulation.

METHODS

A life-sized model of the human aorta and major vascular branches was virtualized using 3-dimensional segmentation software (Mimics, Materialise). Steady-state simulation of different grades of cardiac output (0-100%) was performed using Computational Fluid Dynamics (CFX, ANSYS). A straight cannula [virtualized 16 Fr (5.3 mm)] was inserted into the model via the left common femoral artery. The ECLS flow was varied between 1 and 5 l/min. The pressure boundary conditions at the arterial outlets were selected to demonstrate the downstream vascular system. Qualitative and quantitative analyses concerning flow velocity and direction were carried out in various regions of the model.

RESULTS

During all simulated stages of reduced cardiac output and subsequently adapted ECLS support, retrograde blood flow originating from the ECLS cannula was observed from the cannulation site up to the aortic bifurcation. Analysis of pressure showed induction of zones of negative pressure close to the cannula tip, consistent with the Bernoulli principle. Depending on cannula position and ECLS flow rate, this resulted in negative flow from the ipsilateral superficial femoral artery or the contralateral internal iliac artery. The antegrade flow to the non-cannulated side was generally greater than that to the cannulated side.

CONCLUSIONS

The cannula position and ECLS flow rate both influence lower limb perfusion during femoral ECLS. Therefore, efforts to optimize the cannula position and to avoid limb malperfusion, including placement of a distal perfusion cannula, should be undertaken in patients treated with ECLS.

Impact of cannula design on packed red blood cell transfusions: technical advancement to improve outcomes in extracorporeal membrane oxygenation

Background

Technological improvement has contributed to making veno-venous extracorporeal membrane oxygenation (VV-ECMO) safer and easier, spreading its use in acute respiratory failure (ARF).

Methods

This is a retrospective observational study carried out in the ECMO center at IRCCS-ISMETT, a medical center focused on end-stage organ failure treatment in Italy. We investigated the effect of different cannula designs on the amount of blood product transfused. Eighty-nine consecutive patients affected with ARF on VV-ECMO from 2008 to 2016 were compared according to type of cannulation: older percutaneous cannula (Standard group, 52 patients) and HLS^© BIOLINE-coated, but with shorter drainage cannula (BIOLINE group, 37 patients).

Results

The two study groups were comparable in terms of baseline characteristics [age, body mass index (BMI), Simplified Acute Physiology Score (SAPS-II), Sequential Organ Failure Assessment (SOFA), Predicting Death For Severe ARDS on VV-ECMO (PRESERVE) score] and ECMO management [median hematocrit (Htc), platelet nadir, antithrombin III (AT III), heparin, activated partial thromboplastin time (APTT)]. In the BIOLINE group, a lower amount of packed red blood cells (pRBC) was transfused considering both total number [4 units, interquartile range (IQR) 1-9 vs. 12 units, IQR 5.5-21; P<0.01] and mL of pRBC/day of ECMO support (91, IQR 21-158 vs. 193.5, IQR 140.5-254; P<0.01). In the BIOLINE group, a trend in reduction of ECMO days (P=0.05) and length of intensive care unit (ICU) stay was found (P=0.06), but no differences in rates of ECMO weaning and ICU discharge were evidenced. The BIOLINE group constituted a saving of €1,295.20 per patient/treatment, counting the costs for cannulation and pRBC administration.

Conclusions

More biocompatible and shorter drainage cannula may represent one of the contributing factors to a reduction in transfusions and costs of VV-ECMO in the current ongoing technological improvement in ECMO.

Extracorporeal support, during and after lung transplantation: the history of an idea

During recent years, continuous technological innovation has provoked an increase of extracorporeal life support (ECLS) use for perioperative cardiopulmonary support in lung transplantation. Initial results were disappointing, due to ECLS-specific complications and high surgical risk of the supported patients. However, the combination of improved patient management, multidisciplinary team work and standardization of ECLS protocols has recently yielded excellent results in several case series from high-volume transplant centres. Therein, it was demonstrated that, although the prevalence of complications remains higher in supported patients, there may be no difference in long-term graft function between supported and non-supported patients. These results are important, because most of the patients who require ECLS support in lung transplantation are young and have no other chance to survive, but to be transplanted. Moreover, there is no device for "bridging to destination" therapy in lung transplantation. Of note, the evidence in favour of ECLS support in lung transplantation was never validated by randomized controlled trials, but by everyday experience at the patient bed-side. Here, we review the state-of-the-art ECLS evidence for intraoperative and postoperative cardiopulmonary support in lung transplantation.

Principles and indications of extracorporeal life support in general thoracic surgery

The role of extracorporeal life support (ECLS) has expanded rapidly over the past 15 years to become an important tool in advanced general thoracic surgery practice. Intra-operative and in some cases continued post-operative ECLS is redefining the scope of complex surgical care. ECLS encompasses a spectrum of temporary mechanical support that may remove CO₂, oxygenate or provide hemodynamic support or a combination thereof. The most common modalities used in general thoracic surgery include extracorporeal membrane oxygenation (ECMO), interventional lung assist device (iLA^® Novalung^®, Heilbronn, Germany), and extracorporeal CO₂ removal (ECCO₂R). The ECMO and Novalung^® devices can be used in different modes for the short term or long-term support depending on the situation. In this review, the principles and current applications of ECLS in general thoracic surgery are presented.

Cannulation technique: femoro-femoral

The cannulation technique used during veno-venous extracorporeal membrane oxygenation (VV ECMO) insertion can have a major impact on a patients' overall outcome. We have developed a technique that aims to combine speed and effectiveness, with minimal risk. The steps include: (I) percutaneous cannulation using the Seldinger technique; (II) ultrasound guided access and positioning of cannulas; (III) femoro-femoral circuit configuration with a later option of high flow; (IV) a no skin cut serial dilation technique; (V) non-suturing securing of cannulas and (VI) a non-surgical manual pressure technique of explantation. The following is a discussion around these techniques and their various advantages and disadvantages.

Bridging to lung transplantation with extracorporeal circulatory support: when or when not?

Patients with end-stage lung disease who are candidates for lung transplantation may acutely decompensate before a donor organ becomes available. In this scenario, extracorporeal life support (ECLS) may be considered as a bridge to transplant or as a bridge to decision. In the current chapter, we review the indications, techniques, and outcomes for bridging to lung transplantation with ECLS.

Cardiac Support: Emphasis on Venoarterial ECMO

Major advances have been made in mechanical circulatory support in recent years. Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) provides both pulmonary and circulatory support for critically ill patients with hemodynamic compromise, serving as a bridge to recovery or definitive therapy in the form of transplant or a durable ventricular assist device. In the past, VA ECMO support was used in cases of cardiogenic shock or failure to wean from cardiopulmonary bypass; however, the technology is now being applied to an ever-expanding list of conditions, including massive pulmonary embolism, cardiac arrest, drug overdose, and hypothermia.

Cannulation techniques for extracorporeal life support

The article reviews cannulation strategy for different modes of extracorporeal life support. Technical aspects, pitfalls and complications are discussed for central and peripheral extracorporeal membrane oxygenation (VA, VV, VAV, VVA), biventricular assist device support and extracorporeal CO₂ removal.

Practice characteristics of Emergency Department extracorporeal cardiopulmonary resuscitation (eCPR) programs in the United States: The current state of the art of Emergency Department extracorporeal membrane oxygenation (ED ECMO)

PURPOSE

To characterize the current scope and practices of centers performing extracorporeal cardiopulmonary resuscitation (eCPR) on the undifferentiated patient with cardiac arrest in the emergency department.

METHODS

We contacted all US centers in January 2016 that had submitted adult eCPR cases to the Extracorporeal Life Support Organization (ELSO) registry and surveyed them, querying for programs that had performed eCPR in the Emergency Department (ED ECMO). Our objective was to characterize the following domains of ED ECMO practice: program characteristics, patient selection, devices and techniques, and personnel.

RESULTS

Among 99 centers queried, 70 responded. Among these, 36 centers performed ED ECMO. Nearly 93% of programs are based at academic/teaching hospitals. 65% of programs are less than 5 years old, and 60% of programs perform ≤3 cases per year. Most programs (90%) had inpatient eCPR or salvage ECMO programs prior to starting ED ECMO programs. The majority of programs do not have formal inclusion and exclusion criteria. Most programs preferentially obtain vascular access via the percutaneous route (70%) and many (40%) use mechanical CPR during cannulation. The most commonly used console is the Maquet Rotaflow(®). Cannulation is most often performed by cardiothoracic (CT) surgery, and nearly all programs (>85%) involve CT surgeons, perfusionists, and pharmacists.

CONCLUSIONS

Over a third of centers that submitted adult eCPR cases to ELSO have performed ED ECMO. These programs are largely based at academic hospitals, new, and have low volumes. They do not have many formal inclusion or exclusion criteria, and devices and techniques are variable.