Establishment of a novel miniature veno‐venous extracorporeal membrane oxygenation model in the rat

Recently, veno‐venous extracorporeal membrane oxygenation (V‐V ECMO) has been commonly used in the world to support patients with severe respiratory failure. However, V‐V ECMO is a new technology compared to veno‐arterial extracorporeal membrane oxygenation and cardiopulmonary bypass, and there are few reports of basic research. Although continuing research is desired, clinical research that standardizes conditions such as patients’ background characteristics is difficult. The purpose of this study was to establish a simple and stably maintainable miniature V‐V ECMO model to study the mechanisms of the biological reactions in circulation during V‐V ECMO. The V‐V ECMO system consisted of an original miniature membrane oxygenator, polyvinyl chloride tubing line, and roller pump. The priming volume of this system was only 8 mL. Polyethylene tubing was used to cannulate the right femoral vein as the venous return cannula for the V‐V ECMO system. A 16‐G cannula was passed through the right internal jugular vein and advanced into the right atrium as the conduit for venous uptake. The animals were divided into 2 groups: SHAM group and V‐V ECMO group. V‐V ECMO was initiated and maintained at 50‐60 mL/kg/min, and oxygen was added into the oxygenator during V‐V ECMO at a concentration of 100% (pump flow:oxygen = 1:10). Blood pressure was measured continuously, and blood cells were measured by blood collection. During V‐V ECMO, the blood pressure and hemodilution rate were maintained around 80 mm Hg and 20%, respectively. Hb was kept at >10 g/dL, and V‐V ECMO could be maintained without blood transfusion. It was possible to confirm oxygenation of and carbon dioxide removal from the blood. Likewise, the pH was adequately maintained. There were no problems with this miniature V‐V ECMO system, and extracorporeal circulation progressed safely. In this study, a novel miniature V‐V ECMO model was established in the rat. A miniature V‐V ECMO model appears to be very useful for studying the mechanisms of the biological reactions during V‐V ECMO and to perform basic studies of circulation assist devices.     

Neonatal and pediatric extracorporeal membrane oxygenation using nonocclusive blood pumps: the Vienna experience

Neonatal and pediatric extracorporeal membrane oxygenation (ECMO) is carried out commonly using occlusive blood pumps. Centrifugal pumps provide simple and safe technology for transportation on ECMO. The assistence respiratoire extra corporelle (AREC) system enables single needle venovenous ECMO for infants. We report on our experience with neonatal and pediatric ECMO treatments using nonocclusive blood pumps. One-hundred forty-six ECMO treatments were performed for cardiac, neonatal, and pediatric indications in 54, 19, and 27% of cases. Centrifugal pumps were used in 99, and the AREC system in 42 cases. Hospital mortality was estimated retrospectively and influence of type of pump, type of ECMO belonging to indication group, and lactate at ECMO installation were estimated. Irreversible organ failure leading to ECMO termination was investigated within groups of indications. Survival (recent 50 ECMO treatments) was 80, 70, 43, and 30% after meconium aspiration syndrome, acute respiratory distress syndrome, cardiac surgery, and prolonged resuscitation. Lactate exceeding 100 mg/dl at ECMO installation predicted significantly worse outcome. Cerebral damage was the main reason for ECMO termination in all but persistent circulatory failure in the cardiac group. Myocardial recovery resulted in all except 2 cardiac cases. Nonocclusive blood pumps can be used safely in neonatal and pediatric ECMO. Early installation may improve outcome markedly. In cardiac cases results of surgery should be thoroughly investigated on the table before ECMO installation to prevent hopeless ECMO treatments.     

Outcomes in patients requiring repeat extracorporeal membrane oxygenation

Background

As the number of patients requiring extracorporeal membrane oxygenation (ECMO) increases nationwide, many patients may require ECMO more than once. We review our experience and outcomes in patients requiring repeat ECMO support.

Methods

The Nebraska ECMO Research Database was utilized for data analysis, and repeat ECMO patients (REPs) were compared to the overall ECMO population.

Results

Of 246 patients, 2.4% (6/246) were REPs. There was no statistical difference between the median days of initial support run (P = 0.670) and second support run (P = 0.813) for REPs when comparing to the non‐REP population. Median hospital length of stay for REPs was 53 days (16‐124) compared to the non‐REPs, who had a median hospital length of stay of 22 days (1‐270); P = 0.043. In‐hospital mortality rate for REPs was 50% (3/6) and 50% for non‐REPs (120/240). Survival 30 days postdischarge for REPs was 50% (3/6) compared to non‐REPs at 48.3% (116/240); P = NS.

Conclusions

Outcomes for repeat ECMO patients compare favorably to the overall ECMO population and suggest a need to explore and broaden the clinical indications for repeat ECMO.     

Bloodless extracorporeal membrane oxygenation in the Jehovah's Witness patient

The successful use of prolonged extracorporeal life support with a heart-lung machine was first performed in 1972, as described by Hill et al., on a young man with post-traumatic respiratory failure. The first successful use of extracorporeal membrane oxygenation (ECMO) was 1976 by Bartlett et al. Since this time, the use of ECMO for neonatal and pediatric pulmonary support has become a standard of care in many children's hospitals. The use of ECMO, being a very invasive procedure, is not without risk. In our experience, most patients require multiple transfusions of the different blood components (packed red blood cells, plasma, platelets, and cryoprecipitate). Exposure to one or more blood products often occurs with connection to the ECMO circuit, as the circuit is generally primed with blood products or whole blood. Jehovah's Witnesses (JWs) are known best in the medical community for their refusal of blood products, even at the risk of death, which presents challenges for health care providers. This belief stems from the biblical passages that have been quoted as forbidding transfusion: Genesis 9:3-4, Leviticus 17:13-14, and Acts 15:19-21. This refusal of blood poses even greater challenges when treating the pediatric JW population. When a blood product is deemed medically necessary for the JW patient, the healthcare provider must either seek legal intervention, or support the patient's/family's wishes and associated outcome. This ethical dilemma may be further complicated in the setting of therapies, which may pose additional risks and potentially less clear benefit such as with ECMO. Bloodless cardiac surgery with cardiopulmonary bypass has been reported in the JW population in adults and pediatrics, including neonates. After a thorough search of the literature, no published report of a JW patient being supported on ECMO without blood or blood component utilization was identified. This case report will present our experience with multiple day, bloodless ECMO support of a 17-year-old male patient of the JW faith.     

Venovenous versus venoarterial extracorporeal membrane oxygenation in congenital diaphragmatic hernia

Background: Extracorporeal membrane oxygenation (ECMO) has a significant role as a final rescue modality in severe respiratory failure of the newborn with congenital diaphragmatic hernia (CDH). The objective of this study was to compare the efficiency of venovenous (VV) versus venoarterial (VA) ECMO in newborns with CDH.Methods: A retrospective report of 11 years experience (1990 through 2001) of a single center, comparing VV and VA ECMO is given. VV ECMO was the preferred rescue modality for respiratory failure unresponsive to maximal medical therapy. Only when the placement of a VV ECMO 14F catheter was not possible, VA ECMO was used. Forty-six patients met ECMO criteria; 26 were treated with VV ECMO and 19 with VA ECMO. One patient underwent conversion from VV to VA ECMO.Results: Before ECMO, there was no difference between VV and VA ECMO patients in mean oxygenation index (83 v 83), mean airway pressure (18.4 v 18.9 cm H₂O), ECMO cannulation age (28 v 20 hours), or in the percentage of patients who needed dopamine and dobutamine (100% v 100%). From November 1994, nitric oxide (NO) was available; before ECMO, 11 of 14 (79%) VV ECMO patients received NO versus 9 of 10 (90%) patients in the VA group. VV ECMO patients were larger (3.34 v 2.77 kg; P < .05) and of advanced gestational age (39.0 v 36.9 wk; P < .05) compared with VA ECMO patients. There was no significant difference between VV and VA ECMO patients in survival rate (18 of 26, 69% v 13 of 19, 68%), ECMO duration (152 v 150 hours), time of extubation (32.0 v 33.5 days), age at discharge (73 v 81 days), or incidence of short-term intracranial complications (3.8% v 10.5%) or myocardial stun (3.8% v 15.8%).Conclusions: The authors conclude that VV ECMO is as reliable as VA ECMO in newborns with CDH in severe respiratory failure who need ECMO support and who can accommodate the VV double-lumen catheter. Because of its potential advantages, VV ECMO may be the preferred ECMO method in these infants.     

Pathophysiology of cardiac extracorporeal membrane oxygenation

The treatment of cardiogenic shock using inotropic agents and vascular volume expansion places an added burden on the heart. The resultant increase in cardiac work may cause myocardial ischemia and lead to cardiac arrest. Extracorporeal membrane oxygenation (ECMO) may be used to treat cardiogenic shock. It supports systemic circulation, assures diastolic perfusion of the myocardium, and reduces cardiac workload. The rise in blood pressure associated with restoring systemic circulation afterloads the heart and can cause left atrial hypertension and pulmonary edema. ECMO does not automatically reduce cardiac work, especially in the presence of residual shunts. Left atrial drainage or decompression may be essential in certain patients both to avert pulmonary edema and to reduce cardiac work.     

The effect of hyperoxia on inflammation and platelet responses in an ex vivo extracorporeal membrane oxygenation circuit

Use of extracorporeal membrane oxygenation (ECMO) is expanding, however, it is still associated with significant morbidity and mortality. Activation of inflammatory and innate immune responses and hemostatic alterations contribute to complications. Hyperoxia may play a role in exacerbating these responses. Nine ex vivo ECMO circuits were tested using fresh healthy human whole blood, with two oxygen levels: 21% inspired fraction of oxygen (FiO₂; mild hyperoxia; n = 5) and 100% FiO₂ (severe hyperoxia; n = 4). Serial blood samples were taken for analysis of platelet aggregometry, leukocyte activation, inflammatory, and oxidative stress markers. ECMO resulted in reduced adenosine diphosphate- (P < .05) and thrombin receptor activating peptide-induced (P < .05) platelet aggregation, as well as increasing levels of the neutrophil activation marker, neutrophil elastase (P = .013). Additionally, levels of the inflammatory chemokine interleukin-8 were elevated (P < .05) and the activity of superoxide dismutase, a marker of oxidative stress, was increased (P = .002). Hyperoxia did not augment these responses, with no significant differences detected between mild and severe hyperoxia. Our ex vivo model of ECMO revealed that the circuit itself triggers a pro-inflammatory and oxidative stress response, however, exposure to supra-physiologic oxygen does not amplify that response. Extended-duration studies and inclusion of an endothelial component could be beneficial in characterizing longer term changes.     

Pressure ulcers in paediatric patients on extracorporeal membrane oxygenation

It has been shown that pressure ulcer formation in critically ill paediatric patients increases morbidity and mortality. We sought to identify factors associated with pressure ulcer formation in paediatric patients on extracorporeal membrane oxygenation (ECMO). From December 2014 to 2015, we identified patients at our institution who developed a pressure ulcer to create two cohorts: ulcer and no ulcer. Variables of interest included: type of ECMO, ECMO indication, hours on ECMO, location of cannulas, volume of crystalloid and blood products received during the first 7 days or during the length of the ECMO run, albumin and lactate levels on the day of cannulation, and presence of vasopressor support or steroid therapy. Of 43 patients studied, 11 (25.5%) developed a pressure ulcer. Patients that developed ulcers were older (P = 0.001) and weighed more (P = 0.006). Femoral cannulation was more frequent in the ulcer group (36.4% vs 6.3%, P = 0.029), and duration of ECMO was longer (P = 0.007). Age, weight, duration of ECMO, and femoral cannulation may contribute to the development of pressure ulcers in children who require ECMO support. Further analysis is imperative to identify specific techniques and protocols that will prevent pressure ulcers in this critically ill population.     

Salvage extracorporeal membrane oxygenation for acute type A aortic dissection with coronary malperfusion

Perioperative use of extracorporeal membrane oxygenation (ECMO) in type A aortic dissection is a topic of contention with limited available data. We report the case of a patient presenting in severe cardiogenic shock due to coronary malperfusion and severe aortic insufficiency who was resucitated with ECMO as a bridge to recovery.     

体外膜肺氧合在围术期及危重症患者中的应用进展

体外膜肺氧合(ECMO)作为一种改良的体外生命支持技术,可部分或完全替代患者的心肺功能,为常规治疗策略无效的顽固性心力衰竭和呼吸衰竭患者提供长时间体外心肺支持,使心肺脏器得到休息恢复,为救治原发病争取时间.经过长期的临床实践与不断探索,ECMO技术已取得长足进步.全文就ECMO的工作原理、围术期应用与急症救治作一综述.     

Clinical outcomes of neonatal and pediatric extracorporeal life support: A seventeen‐year,single institution experience

The objective of this study was to describe a single‐center experience with neonatal and pediatric extracorporeal life support (ECLS) and compare patient‐related outcomes with those of the Extracorporeal Life Support Organization (ELSO) Registry. A retrospective review of subject characteristics, outcomes, and complications of patients who received the ECLS at Penn State Health Children’s Hospital (PSHCH) from 2000 to 2016 was performed. Fisher’s exact test was used to compare the PSHCH outcomes and complications to the ELSO Registry report. Data from 118 patients were included. Survival to discontinuation of the ECLS was 70.3% and 65.2% to discharge/transfer. Following circuitry equipment changes, the survival to discharge/transfer improved for both neonatal (<29 days) and pediatric (29 days to <18 years) patients. The most common complications associated with ECLS were clinical seizures, intracranial hemorrhage, and culture‐proven infection. ECLS for pulmonary support appeared to be associated with a higher risk of circuit thrombus and cannula problems. When compared to the ELSO Registry, low volume ECLS centers, like our institution, can have outcomes that are no different or statistically better as noted with neonatal and pediatric cardiac patients. Pediatric patients requiring pulmonary support appeared to experience more mechanical complications during ECLS suggesting the need for ongoing technological improvement.     

Pediatric cardiac extracorporeal membrane oxygenation in congenital heart disease: the cardiologist's view

Abstract: There is no doubt that extracorporeal membrane oxygenation (ECMO) as a powerful therapeutic modality in critically ill newborn infants and older children with congenital heart disease has implications for the pediatric cardiologist. His responsibilities as consultant in the intensive care unit include screening for unsuspected cyanotic heart disease in neonatal candidates referred for ECMO and appraisal of surgical repair in postcardiotomy patients as well as assessment of postoperative hemodynamics and detection of complications during perfusion. A close cooperation between intensive care specialists and other appropriate specialists (pediatric cardiologists, cardiac surgeons, and anesthesiologists) is required for the process of decision making prior to initiation of postoperative ECMO in the individual patient with congenital heart disease. Long-term survival, morbidity, cerebrovascular complications, and neurodevelopmental sequelae of these near miss children remain a critical issue. Furthermore, there is a strong need for professional psychosocial support of affected parents, both in the hospital and after discharge.     

Resuscitation and circulatory support using extracorporeal membrane oxygenation for fulminant pulmonary embolism

Fulminant pulmonary embolism (PE) with circulatory collapse is associated with a high mortality rate due to acute right ventricular failure and hypoxia. Immediate and appropriate resuscitation and circulatory support in the perioperative period is mandatory to prevent sudden death. Extracorporeal membrane oxygenation (ECMO) was recently introduced for extracorporeal life support in patients with circulatory collapse and has provided an excellent outcome. We report on the effectiveness of ECMO support for fulminant PE. Seven patients were placed on veno-arterial ECMO for circulatory collapse caused by fulminant PE refractory to conventional treatment. After resuscitation, all patients underwent pulmonary angiography, and thrombolytic therapy was administered in all 7 patients under ECMO support. Three patients who did not improve by thrombolysis underwent embolectomy with standard cardiopulmonary bypass. Two thrombolysis and 2 surgery patients were weaned from bypass and survived. The duration of support ranged from 18-168 h (mean = 67.8 +/- 67.1 h), with maximum bypass flow rates of 2.0-4.5 (mean = 3.5 +/- 0.9). There were no device-related complications during support. In total, 4 patients (57%) were successfully weaned from support and discharged from the hospital in good condition. All patients who survived required prolonged support (27, 82, 151, and 168 h). We conclude that resuscitation and circulatory support using ECMO can be effective, life-saving measures in cases of circulatory collapse caused by fulminant PE.