Extracorporeal membrane oxygenation with a poly-methylpentene oxygenator (Quadrox D). The experience of a single Italian centre in adult patients with refractory cardiogenic shock

ExtraCorporeal Membrane Oxygenation in the therapy for REfractory Septic shock with Cardiac function Under Estimated (ECMO-RESCUE): study protocol for a prospective, multicentre, non-randomised cohort study

INTRODUCTION

Severe septic cardiomyopathy (SCM) is one of the main causes of refractory septic shock (RSS), with a high mortality. The application of venoarterial extracorporeal membrane oxygenation (ECMO) to support the impaired cardiac function in patients with septic shock remains controversial. Moreover, no prospective studies have been taken to address whether venoarterial ECMO treatment could improve the outcome of patients with sepsis-induced cardiogenic shock. The objective of this study is to assess whether venoarterial ECMO treatment can improve the 30-day survival rate of patients with sepsis-induced refractory cardiogenic shock.

METHODS AND ANALYSIS

ExtraCorporeal Membrane Oxygenation in the therapy for REfractory Septic shock with Cardiac function Under Estimated is a prospective, multicentre, non-randomised, cohort study on the application of ECMO in SCM. At least 64 patients with SCM and RSS will be enrolled in an estimated ratio of 1:1.5. Participants taking venoarterial ECMO during the period of study are referred to as cohort 1, and patients receiving only conventional therapy without ECMO belong to cohort 2. The primary outcome is survival in a 30-day follow-up period. Other end points include survival to intensive care unit (ICU) discharge, hospital survival, 6-month survival, quality of life for long-term survival (EQ-5D score), successful rate of ECMO weaning, long-term survivors' cardiac function, the number of days alive without continuous renal replacement therapy, mechanical ventilation and vasopressor, ICU and hospital length of stay, the rate of complications potentially related to ECMO treatment.

ETHICS AND DISSEMINATION

The trial has been approved by the Clinical Research and Application Institutional Review Board of the Second Affiliated Hospital of Guangzhou Medical University (2020-hs-51). Participants will be screened and enrolled from ICU patients with septic shock by clinicians, with no public advertisement for recruitment. Results will be disseminated in research journals and through conference presentations.

TRIAL REGISTRATION NUMBER

NCT05184296.

Extracorporeal Membrane Oxygenation in Cardiogenic shock – A Review

Extracorporeal membrane oxygenation has been used in adult in cardiogenic shock due to myocardial infarction, myocardiopathy, myocarditis, or inability to come off cardiopulmonary bypass (CPB) after cardiac surgery.3 ECMO can provide partial or total support, but it is temporary. It is not a definitive treatment but a life support system that allows time for evaluation, diagnosis and treatment of the condition that causes heart failure. With high incidence of late stage coronary artery disease and infective myocarditis in India, the usage of ECMO for refractory cardiogenic shock is going to be a promising approach for effective management of refractory heat failure .ECMO has proven to be an effective therapeutic modality in managing cardiovascular collapse as a bridge to recovery or more definitive treatment options.

Left Ventricular Decompression by Transaortic Catheter Venting in Extracorporeal Membrane Oxygenation

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been widely applied to patients with cardiogenic shock. Left ventricle (LV) decompression is important when LV distension develops with pulmonary edema. The purpose of this study was to present the results of transaortic catheter venting (TACV) performed during VA-ECMO. We retrospectively reviewed the medical records of 18 patients who underwent both VA-ECMO and TACV between January 2017 and December 2019. Venoarterial extracorporeal membrane oxygenation was applied uneventfully. Lactate level and norepinephrine requirement for patients of weaning success were lower than those of patients of weaning failure after the application of TACV (p = 0.032 and p = 0.015, respectively). The successful weaning rate of ECMO was 77.8% (15/18) and survival rate was 50% (9/18). Transaortic catheter venting may be an easy, safe, and effective technique for LV decompression in patients with VA-ECMO for cardiogenic shock. Also, this technique may be helpful as an alternative or bridge method.

Staffing, Equipment, Monitoring Considerations for Extracorporeal Membrane Oxygenation

Although the reasons for the recent growth in adult extracorporeal membrane oxygenation (ECMO) are multifactorial, much of the success may be attributed to the development of well-trained staff and the technological innovations in equipment and monitoring devices used during extracorporeal support. In this article, the authors discuss general educational formats for the ECMO bedside provider, staffing support models, and devices designed to best meet the needs of the patient while simultaneously ensuring the proper delivery of ECMO-related care.

Initial Experience of Transaortic Catheter Venting in Patients with Venoarterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock

Extracorporeal membrane oxygenation (ECMO) has become one of the often applied mechanical support for acute cardiogenic shock. During venoarterial (VA) ECMO support, left heart decompression should be considered when left ventricular (LV) distension develops with pulmonary edema and LV dysfunction. The aim of this study was to report the results of transaortic catheter venting (TACV), as an alternative venting method, performed during VA-ECMO in patients with acute cardiogenic shock. We retrospectively reviewed the records of seven patients who underwent both ECMO and TACV between February 2013 and February 2014. Extracorporeal membrane oxygenation was performed uneventfully, and TACV was introduced under transthoracic echocardiographic guidance in all cases. Hemodynamic parameters, LV ejection fraction, and LV end-diastolic dimension (LVEDD) were measured 24 hours after initiating TACV in survivors. There were no procedure-related complications. Four of the seven patients (58%) survived. Transaortic catheter venting led to an increase in mean blood pressure in all patients (p = 0.050). There was a significant difference between pre- and post-TACV-LVEDD (59 ± 14 vs. 50 ± 12 mm, p = 0.044), with a 10-23% reduction in LVEDD in survivors. Transaortic catheter venting might be an acceptable alternative to venting procedures and useful for LV recovery during VA-ECMO in patients with severe LV dysfunction.

Postcardiotomy ECMO Support after High-risk Operations in Adult Congenital Heart Disease

BACKGROUND

Cardiac operations in high-risk adult congenital heart disease (ACHD) patients may require mechanical circulatory support (MCS), such as extracorporeal membrane oxygenation (ECMO) or intraaortic balloon pump (IABP), to allow the cardiopulmonary system to recover.

METHODS

We reviewed records for all ACHD patients who required MCS following cardiotomy at our institution from 1/2001 to 12/2013.

RESULTS

During the study period, 2264 (mean age 39.1 years, females ∼54.1%) operations were performed in ACHD patients of whom 24 (1.1%) required postoperative MCS (14 males; median age 41 years, range 22-75). Preoperatively the 24 patients had a mean systemic ventricular ejection fraction of 47% (range 10-66%); 72% of these patients were in NYHA class III/IV heart failure. The common underlying diagnoses included pulmonary atresia with intact ventricular septum (20%), tetralogy of Fallot (16%), Ebstein anomaly (12%), cc-TGA (12%), septal defects (12%), and others (28%). Operations performed were valvular operations with/without maze (58.2%), Fontan conversion (21%), coronary bypass grafting with valvular operations (12.5%), and heart transplant (8.3%). Indications for MCS were left-sided (systemic) heart failure (32%), right-sided (subpulmonary) heart failure (24%), biventricular heart failure (36%), persistent arrhythmia (4%), and hypoxemia (4%). Forty-two percent were placed on ECMO only; in the second group, IABP was attempted and subsequently followed by ECMO initiation. The mean duration of MCS was 8.4 days (range 0.8-35.4). Common morbidities included coagulopathy (60%), renal failure (56%), and arrhythmia (48%). Overall, 46% of patients survived to hospital discharge. Deaths were due to either multi organ failure or the underlying cardiac disease; sepsis was the primary cause of death in one patient. Median follow-up for survivors was 41 months (maximum 106 months). NYHA functional class was I/II in all 8 late survivors.

CONCLUSIONS

Following complex operations in high-risk ACHD patients, MCS may be required. Despite significant morbidity, nearly half of patients survive to hospital discharge.

Case Records of the Massachusetts General Hospital. Case 30-2015: A 50-Year-Old Man with Cardiogenic Shock

A 50-year-old man with a history of cardiomyopathy and progressive muscle weakness was admitted with cardiogenic shock. Electroencephalography showed total suppression of cerebral activity; ventilator support was withdrawn, and he died. An autopsy was performed.

Influence of different oxygenator types on changing frequency, infection incidence, and mortality in ARDS patients on veno-venous ECMO

PURPOSE

Veno-venous extracorporeal membrane oxygenation (vv-ECMO) is pivotal in the treatment of patients suffering from acute respiratory distress syndrome (ARDS). Comparative data with different oxygenator models have not yet been reported. The aim of this retrospective investigation was therefore to assess whether different oxygenator types might influence changing frequency, infection incidence, and mortality in patients on vv-ECMO.

METHODS

42 patients undergoing vv-ECMO between 1998 and 2009 were identified. In 20 out of these patients, a polypropylene (PP) microporous hollow fiber membrane oxygenator, and in 22 patients a nonmicroporous polymethylpentene (PMP) diffusion membrane oxygenator was used. Infection incidence, changing frequency, and mortality were documented.

RESULTS

In the PMP group, an oxygenator change was necessary less often than in the PP group (p<0.001). The incidence of bacterial, viral, or fungal growth was similar in the groups, thus independent of the frequency of oxygenator change. Irrespective of the groups, the occurrence of Candida sp. tended to correlate with death (p = 0.06). In general, there was a trend towards a higher infection incidence in the subgroup with pulmonary ARDS (p = 0.07). Moreover, infection incidence was associated with a longer ICU stay (p = 0.03) and longer ECMO therapy (p = 0.03). ICU mortality was lower in the PMP group than in the PP group, although not statistically significant (p = 0.10).

CONCLUSIONS

The PMP oxygenator membranes showed benefits with regards to changing frequency, but not infection incidence, length of ICU stay, and length of ECMO therapy. There was a trend towards a lower ICU mortality in patients with PMP oxygenators.

Mechanical circulatory support in acute cardiogenic shock

Cardiogenic shock complicates about 5% to 8% of all admissions for acute myocardial infarction, and despite advancement in treatment over the past 50 years, mortality remains unacceptably high. Management with vasoactive agents after revascularization can have its limitations and thus mechanical circulatory support is often initiated. Intra-aortic balloon pumps (IABPs) are the devices most commonly used worldwide. IABPs appeared to improve mortality when used along with fibrinolytic therapy but may not when used along with percutaneous coronary interventions. Extracorporeal membrane oxygenation (ECMO) is utilized in the setting of worsening tissue perfusion despite inotropes and IABP utilization. Although retrospective studies show some mortality benefit, randomized prospective studies have not yet demonstrated ECMO to be advantageous either with or without IABP. Percutaneous left ventricular assist devices such as TandemHeart® and Impella are easier to institute than ECMO and are better for hemodynamics compared with the IABP but also have not yet shown a mortality benefit. More randomized studies are needed to define the most appropriate role of the various mechanical support devices in cardiogenic shock.

Comparison of hemolysis between CentriMag and RotaFlow rotary blood pumps during extracorporeal membrane oxygenation

The purpose of this investigation was to compare the hemolysis levels for patients on extracorporeal membrane oxygenation (ECMO) incorporating two different rotary blood pumps (CentriMag [CMAG] and RotaFlow [RF]) in identical circuits otherwise. The difference between the two pumps is the cost. One is 20-30 times less expensive than the other. A retrospective analysis of all patients placed on ECMO from June 2008 through May 2012 was done to evaluate hemolysis. Daily plasma hemoglobin (pHb), lactate dehydrogenase (LDH), and lactate levels were collected on all patients. Values were compared between those patients who received a CMAG and those who received an RF. Patients had to be on ECMO for more than 2 days to be included in the study. Linear mixed effects models were fit to the data to assess differences over time for each continuous outcome. Forty patients were placed on ECMO incorporating CMAG, whereas 40 patients received an RF. There were no significant statistical differences between CMAG and RF groups when comparing days on support (8.7 ± 5.0; 8.4 ± 5.7), age (44.8 ± 18.3; 46.1 ± 16.0), body surface area (2.03 ± 0.36; 1.96 ± 0.31), gender (male: 58%, female: 42%; male: 55%, female: 45%), etiology, type of support (veno-arterial [VA)]: 78%, veno-venous [VV)]: 22%; VA: 82%, VV: 18%) and pre-ECMO LDH levels (4004.0 ± 3583.2; 3603.7 ± 3354.1). There were also no significant differences between the CMAG and RF groups when comparing the mean values for daily pHb levels (5.7 ± 3.6; 5.7 ± 4.2), lactate levels (2.8 ± 1.9; 3.0 ± 2.1), and LDH levels (2656.3 ± 1606.8; 2688.6 ± 1726.1) or daily lactate, LDH, and pHb levels for the first 10 days of support. From our investigation, there is no difference between the CMAG and the RF blood pumps in regard to the creation of hemolysis during ECMO. The difference in cost of the devices does not correlate with the performance and outcomes.

New generation extracorporeal membrane oxygenation with MedTech Mag-Lev, a single-use, magnetically levitated, centrifugal blood pump: preclinical evaluation in calves

We have evaluated the feasibility of a newly developed single-use, magnetically levitated centrifugal blood pump, MedTech Mag-Lev, in a 3-week extracorporeal membrane oxygenation (ECMO) study in calves against a Medtronic Bio-Pump BPX-80. A heparin- and silicone-coated polypropylene membrane oxygenator MERA NHP Excelung NSH-R was employed as an oxygenator. Six healthy male Holstein calves with body weights of about 100 kg were divided into two groups, four in the MedTech group and two in the Bio-Pump group. Under general anesthesia, the blood pump and oxygenator were inserted extracorporeally between the main pulmonary artery and the descending aorta via a fifth left thoracotomy. Postoperatively, both the pump and oxygen flow rates were controlled at 3 L/min. Heparin was continuously infused to maintain the activated clotting time at 200-240 s. All the MedTech ECMO calves completed the study duration. However, the Bio-Pump ECMO calves were terminated on postoperative days 7 and 10 because of severe hemolysis and thrombus formation. At the start of the MedTech ECMO, the pressure drop across the oxygenator was about 25 mm Hg with the pump operated at 2800 rpm and delivering 3 L/min flow. The PO2 of the oxygenator outlet was higher than 400 mm Hg with the PCO2 below 45 mm Hg. Hemolysis and thrombus were not seen in the MedTech ECMO circuits (plasma-free hemoglobin [PFH] < 5 mg/dL), while severe hemolysis (PFH > 20 mg/dL) and large thrombus were observed in the Bio-Pump ECMO circuits. Plasma leakage from the oxygenator did not occur in any ECMO circuits. Three-week cardiopulmonary support was performed successfully with the MedTech ECMO without circuit exchanges. The MedTech Mag-Lev could help extend the durability of ECMO circuits by the improved biocompatible performances.

Mechanical circulatory support for cardiogenic shock

Cardiogenic shock (CS) is a syndrome of progressive depression of myocardial function with systemic hypoperfusion. It occurs due to various aetiologies such as acute myocardial infarction, myocarditis, acute decompensated heart failure and postcardiotomy. Cardiogenic shock carries poor prognosis, and medical therapy alone is not effective. Mechanical circulatory support is required to unload the ventricles, decrease the myocardial demand, prevent further injury, improve the coronary perfusion, stabilise the haemodynamics and maintain the end-organ perfusion before definitive interventions such as coronary reperfusion can take place. Currently, there are several methods of mechanical circulatory support. These include extracorporeal life support, paracorporeal or extracorporeal ventricular-assist devices, percutaneous ventricular assist devices, intra-aortic balloon counterpulsation and total artificial heart. In this review, we discuss the role of each of these circulatory support devices in the management of acute cardiac failure.

The cost-effectiveness of a new percutaneous ventricular assist device for high-risk PCI patients: mid-stage evaluation from the European perspective

OBJECTIVE

A new and smaller percutaneous ventricular assist device (pVAD, Impella, Abiomed, Danvers, MA) has been developed to provide circulatory support in hemodynamically unstable patients and to prevent hemodynamic collapse during high-risk percutaneous coronary interventions (PCI). The objective of the study was to assess the cost-effectiveness of this specific device compared to the intra-aortic balloon pump (IABP) from the European perspective. Additional analysis on extracorporeal membrane oxygenation was conducted for observational purposes only, given its use in some European countries.

METHODS

A combination of a decision tree and Markov model was developed to assess the cost-effectiveness of the small, pVAD. The short-term (30-day) effectiveness and safety (early survival, risk of bleeding, and stroke) were modeled, as well as long-term risk of major adverse cardiovascular events (recurrent myocardial infarction, stroke, and heart failure). The short-term effectiveness and safety data for the device were obtained from two registries (the Europella and USpella), both of which are large multi-center studies in high-risk patient groups. Probabilities of long-term major adverse cardiovascular events were obtained from various published clinical studies. The economic analysis was conducted from a German statutory health insurance perspective and only direct medical costs were included. Cost-effectiveness was estimated over a 10-year time horizon.

RESULTS

Compared with IABP, the pVAD generated an incremental quality-adjusted life-year (QALY) of 0.22 (with Euro-registry data) and 0.27 (with US-registry data). The incremental cost-effectiveness ratio (ICER) of the device varied between €38,069 (with Euro-registry data) and €31,727 (with US-registry data) per QALY compared with IABP.

KEY LIMITATIONS

Unadjusted, indirect comparisons of short-term effectiveness and safety between the interventions were used in the model. Cost and utility data were retrieved from various sources. Therefore, differences in patient populations may bias the estimated cost-effectiveness.

CONCLUSIONS

Compared with IABP, the pVAD is a cost-effective intervention for high-risk PCI patients, with ICERs well-below the conventional cost-effectiveness threshold.

A new phosphorylcholine-coated polymethylpentene oxygenator for extracorporeal membrane oxygenation: a preliminary experience

Phosphorylcholine coating has a major role in the improvement of biocompatibility, durability and antihrombogenicity of the circuit for extracorporeal membrane oxygenation (ECMO). Moreover, if heparin-induced thrombocytopenia ensues, removal of all the sources of heparin is challenging if the circuit is coated with heparin.

We report our preliminary experience with the new EUROSETS A.L.ONE ECMO oxygenator (Eurosets, Medolla, MO, Italy), which is aimed at providing better biocompatibility thanks to its full coating with phosphorylcholine. We retrospectively collected data on the 16 patients supported with ECMO and with the EUROSETS A.L.ONE ECMO oxygenator at San Raffaele Hospital. Mean ECMO duration was 6 ± 4 days, and 37.5% of the patients died on ECMO. Four episodes of major bleeding and three episodes of minor bleeding were recorded. The oxygenator had an excellent performance in gas exchange and the median pressure drop was 57 (26-85) mmHg at full blood flow (2.5 L/m2/min).

The EUROSETS A.L.ONE ECMO oxygenator was an excellent device in our preliminary experience. Further evaluation on a larger sample is encouraged.

Have changes in ECMO technology impacted outcomes in adult patients developing postcardiotomy cardiogenic shock?

Extracorporeal membrane oxygenation (ECMO) technology has undergone several advancements over the last decade. We sought to compare current ECMO technology to older ones to determine how these technological improvements have impacted outcomes in patients suffering from postcardiotomy cardiogenic shock (PCS). Between 2005 and 2010, 49 patients received ECMO as support for PCS following elective cardiac surgery. Patients were divided into three groups. Group 1 (Gp 1, n = 11) patients received a Biomedicus pump with an Affinity oxygenator, Group 2 (Gp 2, n = 11) patients received a Biomedicus pump with a Quadrox D oxygenator, and Group 3 (Gp 3, n = 27) patients received a Rotaflow pump with a Quadrox D oxygenator. Groups were compared with regards to adverse events and ability to wean. Adverse event analysis showed no statistically significant difference between groups in incidence of stroke (p = 0.08), renal failure (p = 0.88), or bleeding requiring reexploration (p = 0.10). Changes in technology did little to improve weaning rates from ECMO (Gp 1 = 63.6%, Gp 2 = 45.5%, and Gp 3 = 55.6%). Similar trends were detected in hospital survival (Gp 1 = 27.3%, Gp 2 = 27.3%, and Gp 3 = 33.3%). Technology did impact oxygenator durability with Gp 1 requiring seven (63.6%) oxygenator exchanges compared to zero (0.0%) in Gp 2 and two (7.4%) in Gp 1. While advancements in ECMO technology have resulted in improved oxygenator durability, outcomes in patients requiring such support for PCS continue to be poor.

Emergency cardiac surgery in patients with acute coronary syndromes: a review of the evidence and perioperative implications of medical and mechanical therapeutics

Patients with acute coronary syndromes who require emergency cardiac surgery present complex management challenges. The early administration of antiplatelet and antithrombotic drugs has improved overall survival for patients with acute myocardial infarction, but to achieve maximal benefit, these drugs are given before coronary anatomy is known and before the decision to perform percutaneous coronary interventions or surgical revascularization has been made. A major bleeding event secondary to these drugs is associated with a high rate of death in medically treated patients with acute coronary syndrome possibly because of subsequent withholding of antiplatelet and antithrombotic therapies that otherwise reduce the rate of death, stroke, or recurrent myocardial infarction. Whether the added risk of bleeding and blood transfusion in cardiac surgical patients receiving such potent antiplatelet or antithrombotic therapy before surgery specifically for acute coronary syndromes affects long-term mortality has not been clearly established. For patients who do proceed to surgery, strategies to minimize bleeding include stopping the anticoagulation therapy and considering platelet and/or coagulation factor transfusion and possibly recombinant-activated factor VIIa administration for refractory bleeding. Mechanical hemodynamic support has emerged as an important option for patients with acute coronary syndromes in cardiogenic shock. For these patients, perioperative considerations include maintaining appropriate anticoagulation, ensuring suitable device flow, and periodically verifying correct device placement. Data supporting the use of these devices are derived from small trials that did not address long-term postoperative outcomes. Future directions of research will seek to optimize the balance between reducing myocardial ischemic risk with antiplatelet and antithrombotics versus the higher rate perioperative bleeding by better risk stratifying surgical candidates and by assessing the effectiveness of newer reversible drugs. The effects of mechanical hemodynamic support on long-term patient outcomes need more stringent analysis.

Short-term Mechanical Circulatory Support with a Centrifugal Pump - Results of Peripheral Extracorporeal Membrane Oxygenator According to Clinical Situation

Background

A peripheral extracorporeal membrane oxygenator (p-ECMO) has been developed to support patients who are dying due to a serious cardiopulmonary condition. This analysis was planned to define the clinical situation in which the patient benefits most from a p-ECMO.

Material and Methods

Between June 2007 and Aug 2009, a total of 41 adult patients used the p-ECMO. There were 23 males and 18 females (mean age 54.4±15.1 years). All patients had very unstable vital signs with hypoxia and complex cardiac problems. We divided the patients into 4 groups. In the first group, a p-ECMO was used as a bridge to cardiac operation. In the second group, patients did not have the opportunity to undergo any cardiac procedures; nevertheless, they were treated with a p-ECMO. In the third group, patients mostly had difficulty in weaning from CPB (cardiopulmonary bypass) after cardiac operation. The fourth group suffered from many complications, such as pneumonia, bleeding, infections, and LV dysfunction with underlying cardiac problems. All cannulations were performed by the Seldinger technique or cutting down the femoral vessel. A long venous cannula of DLP® (Medtronic Inc, Minneapolis, MN) or RMI® (Edwards Lifesciences LLC, Irvine, CA) was used together with a 17~21 Fr arterial cannula and a 21 Fr venous cannula. As a bypass pump, a Capiox emergency bypass system (EBS®; Terumo, Tokyo, Japan) was used. We attempted to maintain a flow rate of 2.4~3.0 L/min/m² and an activated clotting time (ACT) of around 180 seconds.

Results

Nine patients survived by the use of the p-ECMO. Ten patients were weaned from a p-ECMO but they did not survive, and the remainder had no chance to be weaned from the p-ECMO. The best clinical situation to apply the p-ECMO was to use it as a bridge to cardiac operation and for weaning from CPB after cardiac operation.

Conclusion

Various clinical results were derived by p-ECMO according to the clinical situation. For the best results, early adoption of the p-ECMO for anatomical correction appears important.

The use of extracorporeal membrane oxygenation in severe necrotizing soft tissue infections complicated by septic shock

Necrotizing soft tissue infections remain a challenging clinical problem. Delays in diagnosis, incomplete débridement of necrotic tissues, and the hemodynamic instability and end-organ failure associated with overwhelming sepsis all contribute to significant mortality. Extracorporeal support is a well-established tool to support profound cardiopulmonary failure. To broaden the indications for use, we present two cases of young adults with necrotizing soft tissue infections who sustained sepsis-induced hemodynamic collapse and required extracorporeal support to facilitate adequate tissue débridement as a bridge to recovery.

An investigational study of minimum rotational pump speed to avoid retrograde flow in three centrifugal blood pumps in a pediatric extracorporeal life support model

During extracorporeal life support with centrifugal blood pumps, retrograde pump flow may occur when the pump revolutions decrease below a critical value determined by the circuit resistance and the characteristics of the pump. We created a laboratory model to evaluate the occurrence of retrograde flow in each of three centrifugal blood pumps: the Rotaflow, the CentriMag, and the Bio-Medicus BP-50. At simulated patient pressures of 60, 80, and 100 mmHg, each pump was evaluated at speeds from 1000 to 2200 rpm and flow rates were measured. Retrograde flow occurred at low revolution speeds in all three centrifugal pumps. The Bio-Medicus pump was the least likely to demonstrate retrograde flow at low speeds, followed by the Rotaflow pump. The CentriMag pump showed the earliest transition to retrograde flow, as well as the highest degree of retrograde flow. At every pump speed evaluated, the Bio-Medicus pump delivered the highest antegrade flow and the CentriMag pump delivered the least.

Thromboembolic Events in Patients on Extracorporeal Membrane Oxygenation without Anticoagulation

Objective

Heparinization is thought to be mandatory to avoid thromboembolic complications during venoarterial extracorporeal membrane oxygenation (VA-ECMO). However, bleeding complications are common. We report our experience of VA-ECMO without systemic anticoagulation.

Methods

A prospectively assembled database describing all ECMO cases from 2000 to 2008 was analyzed. A heparin coated circuit (Medtronic, Inc., Minneapolis, MN USA) and membrane oxygenator (Quadrox D Bioline oxygenator; MAQUET, Rastatt, Germany) were used in all cases. After the initiation of VA-ECMO support, all coagulation parameters were corrected. No further systemic maintenance anticoagulant was given, except at the time of weaning.

Results

Thirty-two patients received VA-ECMO support; 20 patients (62.5%) were males with a median age of 52.5 years (interquartile range, 40.4–61.1 years). Central and peripheral cannulations were 53% and 47%, respectively. Etiologies of cardiogenic shock were postcardiotomy (75%, n = 24) and as a support to cardiopulmonary resuscitation in 25% of cases (n = 8). Thirty-day mortality was 43.8%. Median duration of ECMO support was 46.3 hours (interquartile range, 26.8–87.8 hours). The median number of packed red blood cell transfusions was 18 ± 25. Complications include five patients (16%) with limb ischemia requiring intervention, 15 patients (46.9%) had acute renal failure, two patients had deep vein thrombosis, and two patients had intracardiac clots detected on echocardiograms. No patient had a cerebrovascular event. Incidence of membrane oxygenator failure was low, requiring replacement in three patients; no adverse event occurred during replacement. Fourteen patients (43.8%) were re-explored for bleeding. Fourteen patients (44%) were discharged home and were long-term survivors.

Conclusions

VA-ECMO support without systemic anticoagulation may reduce bleeding complications and transfusion requirement, without increasing the risk of thromboembolism.

Clinical review: mechanical circulatory support for cardiogenic shock complicating acute myocardial infarction

Acute myocardial infarction is one of the 10 leading reasons for admission to adult critical care units. In-hospital mortality for this condition has remained static in recent years, and this is related primarily to the development of cardiogenic shock. Recent advances in reperfusion therapies have had little impact on the mortality of cardiogenic shock. This may be attributable to the underutilization of life support technology that may assist or completely supplant the patient's own cardiac output until adequate myocardial recovery is established or long-term therapy can be initiated. Clinicians working in the intensive care environment are increasingly likely to be exposed to these technologies. The purpose of this review is to outline the various techniques of mechanical circulatory support and discuss the latest evidence for their use in cardiogenic shock complicating acute myocardial infarction.

Mechanical performance comparison between RotaFlow and CentriMag centrifugal blood pumps in an adult ECLS model

Introduction: Centrifugal blood pumps have been widely adopted in conventional adult cardiopulmonary bypass and circulatory assist procedures. Different brands of centrifugal blood pumps incorporate distinct designs which affect pump performance. In this adult extracorporeal life support (ECLS) model, the performances of two brands of centrifugal blood pump (RotaFlow blood pump and CentriMag blood pump) were compared.

Methods: The simulated adult ECLS circuit used in this study included a centrifugal blood pump, Quadrox D membrane oxygenator and Sorin adult ECLS tubing package. A Sorin Cardiovascular® VVR® 4000i venous reservoir (Sorin S.p.A., Milan, Italy) with a Hoffman clamp served as a pseudo-patient. The circuit was primed with 900ml heparinized human packed red blood cells and 300ml lactated Ringer’s solution (total volume 1200 ml, corrected hematocrit 40%). Trials were conducted at normothermia (36°C). Performance, including circuit pressure and flow rate, was measured for every setting analyzed.

Results: The shut-off pressure of the RotaFlow was higher than the CentriMag at all measurement points given the same rotation speed (p < 0.0001). The shut-off pressure differential between the two centrifugal blood pumps was significant and increased given higher rotation speeds (p < 0.0001). The RotaFlow blood pump has higher maximal flow rate (9.08 ± 0.01L/min) compared with the CentriMag blood pump (8.37 ± 0.02L/min) (p < 0.0001). The blood flow rate differential between the two pumps when measured at the same revolutions per minute (RPM) ranged from 1.64L/min to 1.73L/min.

Conclusions: The results obtained in this experiment demonstrate that the RotaFlow has a higher shut-off pressure (less retrograde flow) and maximal blood flow rate than the CentriMag blood pump. Findings support the conclusion that the RotaFlow disposable pump head has a better mechanical performance than the CentriMag. In addition, the RotaFlow disposable pump is 20-30 times less expensive than the CentriMag.

Extracorporeal membrane oxygenation to support adult patients with cardiac failure: predictive factors of 30-day mortality

Adult patients supported on extracorporeal membrane oxygenation (ECMO) are very sick and many complications are often present in each single patient; therefore, it is not always easy to find some risk factors that can predict the early outcome. This retrospective study reports our experience in ECMO support treatment in adult cardiac patients suffering from cardiac failure (CF) in which one or more predictive factors of 30-day mortality were analyzed. Between January 2002 and August 2009, 42 consecutive adult cardiac patients with cardiogenic shock (mean age 64.3+/-11.3 years) were supported on ECMO for >2 days. They were divided into patients who had a survival <30 days (n=20) and patients who survived >30 days (n=22). Twenty-nine patients (69%) survived on ECMO. Sixteen patients were discharged with a survival rate of 38.1%. The overall mean ECMO duration was 7.9+/-5.3 days. The following variables were significantly different between the two groups: number of platelets and packed red blood cells (PRBCs) transfused per day during ECMO (P=0.002 and P=0.003), blood lactate levels 48 h and 72 h after the initiation of ECMO (P=0.01 and P=0.04), indexed blood flow after 48 h and 72 h (P=0.01 and P<0.0001), liver failure (P=0.001) and multiorgan failure (P=0.002). Stepwise logistic regression identified that blood lactate levels at 48 h and number of PRBCs transfused were associated with 30-day mortality [P=0.019, odds ratio (OR) =2.16; 95% confidence interval (CI)=1.13-4.14 and P=0.008, OR=1.08; 95% CI=1.02-1.14, respectively]. The predicted probability of mortality would be 52% when blood lactate levels are >3 mmol/l after 48 h. The blood lactate level at 48 h and PRBCs transfused per day can be considered as important parameters to predict the mortality in adult cardiac patients supported by ECMO for CF.

Treatment of massive pulmonary embolism utilizing a multidisciplinary approach: a case study

Massive pulmonary embolism (PE) is associated, historically, with a high mortality rate.Treatment options include systemic anticoagulation, catheter-directed thrombolytic therapy, surgical embolectomy, fragmentation techniques, and catheter embolectomy. Extracorporeal membrane oxygenation (ECMO) repeatedly has demonstrated effectiveness in providing cardiopulmonary support for the patient with a massive PE too unstable to undergo thrombolysis or embolectomy. The present case study describes a morbidly obese patient, status post gastric bypass surgery, who presented with PE, and acute respiratory and cardiac failure. A description of the patient’s management plan, which includes a simple, rapidly deployed ECMO system (Levitronix® CentriMag® and Jostra Quadrox D), systemic- and catheter-directed thrombolytic therapy and rheolytic thrombectomy (AngioJet® Series 3000, Possis Medical, Minneapolis, MN).

Successful treatment of peripartum cardiomyopathy with extracorporeal membrane oxygenation

A 24-year-old female developed heart failure within four months of delivering her first child. Echocardiogram revealed a moderately dilated left ventricle with severely reduced systolic function. She continued to decompensate, requiring intubation and inotropic support. When the use of an intra-aortic balloon pump failed to stabilize the patient, the decision was made to place her on ECMO. The circuit consisted of a Quadrox D membrane oxygenator and a CentriMag® centrifugal pump. After 11 days of support, the patient met the weaning criteria and was successfully removed from ECMO. She was discharged one month after her admission. The new technology available allows for ECMO to be considered as an earlier option for the treatment and management of these patients as a bridge to recovery.