Prolonged total extracorporeal lung assistance without systemic heparinization

A 16-year-old female developed severe ARDS in her single remaining lung following pneumonectomy for blunt trauma. Total extracorporeal lung assist (ECLA) for 40 days using a covalently heparin-coated circuit proved lifesaving. Systemic heparinization was not applied, as the heparinized surface by itself prevented clotting of the extracorporeal circuit. Systemic primary fibrinolysis developed but was not associated with major bleeding. A veno-right ventricular cannulation technique was used and maximum venous drainage for the extracorporeal circulation was achieved by elevating the bed 50 cm from the floor. This allowed extracorporeal blood flow (ECBF) approaching cardiac output (CO) and complete extracorporeal replacement of lung function. After 40 days, lung recovery allowed discontinuation of ECLA. Five days later the patient suffered serious lung collapse and was operated for a bronchopleural fistula. The patient was extubated 4 weeks after terminating ECLA and discharged in good condition 5 weeks later.     

Use of an extracorporeal left ventricular assist system after acute myocardial infarction due to occlusion of the keft main coronary artery

A 35-year-old man presented to our institution one day after the onset of dyspnea. Coronary angiography revealed the occlusion of the left main trunk. The left main coronary artery and the left circumflex artery were recanalized, but he was hypotensive with low cardiac output. Even after he was placed on circulatory support with veno-arterial extracorporeal membrane oxygenation (ECMO), hemodynamic deterioration could not be reversed, and lung edema developed. The decision was made to use Toyobo LVAS?. With institution of left ventricular assist system (LVAS), however, the patient’s arterial saturation decreased. Peripheral veno-venous (V-V) ECMO was promptly established, and the patient’s arterial saturation improved. On postoperative day 3, the patient was successfully weaned from V-V ECMO. He was extubated on postoperative day 28. The patient was recovered without any serious complications. Although echocardiography showed no substantial improvement in left ventricular function, his general condition is doing quite well with the assist of Toyobo LVAS?. He is on rehabilitation program and awaiting heart transplantation.     

Heparin-coated adult ECMO vs. ventricular assist devices: a decision analysis modeling approach

Postcardiotomy failure requiring ventricular assist occurs in about 1% of adult patients undergoing cardiac surgical procedures. One method of support is a short-term ventricular assist device. This incurs the cost of the device, which is substantial, and allows for reduced anticoagulation in the first 24 hours. Another option is a heparin-coated extracorporeal membrane oxygenation (ECMO) circuit. This also allows for reduced anticoagulation and can support the lungs if necessary. The use of a heparin-coated ECMO circuit requires 24-hour monitoring, but the cost of disposables is considerably less than the cost of ventricular assist devices. This decision analysis uses a Markov model to evaluate the relative outcomes and costs associated with selection between these modalities of support. Data from the past 5 years of patients who received postcardiotomy support will be used to develop the Markov model. The hypothesis is that supporting the patient on heparin-coated ECMO before instituting ventricular assistance will reduce cost and allocate resources in a more cost-effective manner. The model was used to determine the optimal economic time for initiation of ventricular assist devices in postcardiotomy patients. The total costs associated with support begin to level out between postoperative days 6 and 10 using an Abiomed BVS5000 ventricular assist device. The largest decline in costs occurs after postoperative day 3. This model suggests that patients should be supported on heparin-coated ECMO for 2-3 days to evaluate their potential for recovery before instituting more expensive ventricular assist devices.     

A New Heparin-Bonded Dense Membrane Lung Combined with Minimal Systemic Heparinization Prolonged Extracorporeal Lung Assist in Goats

Heparin was covalently bonded to a new hollow-fiber dense membrane artificial lung and extracorporeal circuit using a silane coupling agent and polyethyleneimine. This study investigated whether prolonged, venoarterial bypass extracorporeal lung assist (V-A bypass ECLA) could be sustained in a goat by the combination of the new membrane lung and minimal systemic heparinization. We maintained ECLA with the hollow-fiber lungs (surface area, 0.8 m²) and circuits by titrating the activated clotting time (ACT) to below 150 s with minimal systemic heparinization in 5 goats. The outcome was assessed from the function of the artificial lung via macro and microscopic examinations after the experiments and the incidence of systemic complications. The 5 goats were maintained on ECLA for 6 to 27 days. The bypass flow rate, blood gases at the return and drainage sites, platelet counts, and platelet aggregation activity were well maintained. Although the hemoglobin concentration, hematocrit, and plasma protein at the start of the ECLA were significantly lower than the pre-ECLA values due to hemodilution, the values remained stable during ECLA. A cerebral infarction occurred in 1 goat. However, in the other 4 goats, no complications such as bleeding, thrombosis, or plasma leakage from the artificial lung were observed. Although several thrombi were observed in the stagnant area of the artificial lung, these local thrombi did not cause the function of the artificial lung to deteriorate. We found that this new type of highly biocompatible, dense membrane artificial lung, when combined with minimal systemic heparinization, prolonged ECLA without the deterioration of the artificial lung function and was suitable for prolonged ECLA.     

Comparison of a new heparin-coated dense membrane lung with nonheparin-coated dense membrane lung for prolonged extracorporeal lung assist in goats

Thrombosis and bleeding are major complications in cases of prolonged extracorporeal lung assist (ECLA) with an artificial-membrane lung. Antithrombogenic treatment of the artificial-membrane oxygenator and circuits is indispensable for safe ECLA. The efficacy of a new heparin-coated membrane lung with minimal systemic heparinization was evaluated for 7 days and compared with a nonheparin-coated membrane lung in goats. The animals were randomly assigned to either the heparin-coated membrane group (HM group, n = 5) or nonheparin-coated membrane group (NHM group, n = 5). Activated coagulation time (ACT) during ECLA was controlled to below 150 s in the HM group, and to near 200 s in the NHM group. All goats in the HM group were sustained on ECLA for 7 days, but two goats in the NHM group died on the 4th and 6th days, respectively. The mean systemic administration rate of heparin during ECLA was 22.4 +/- 4.4 U/kg/h in the HM group and 39.0 +/- 10.0 U/kg/h in the NHM group. There was a significant difference between the two groups (P < 0.05). The oxygen transfer rate, the Pco(2) difference, the perfusion resistance, and platelet counts showed no significant changes. There was no plasma leakage from the artificial lung. Although several clots were observed in the stagnant areas of the artificial lung, they did not lead to deterioration of the function of the artificial lung. The excellent antithrombogenicity, gas exchange ability, and durability of this new artificial lung with circuits might contribute to successful prolonged ECLA with minimal systemic heparinization.     

Intratracheal stent intubation under extracorporeal lung assist

An artificial stent was intubated using extracorporeal lung assist (ECLA) in two patients with inoperable tracheal stenosis. In a patient with an endotracheal tumor, an airway obstruction due to a partial stent collapse was overcome by an immediate ECLA perfusion. In another patient with chronic inflammatory tracheal stenosis, a repetitive balloon dilation of the trachea could be safely performed utilizing ECLA perfusion. Preventive femoral cannulation, employing the assistance of an ECLA circuit, is thus considered to be a safe and effective procedure for the treatment of inoperable tracheal stenosis.     

Current Status of Heart Assist and Replacement in Taiwan

Abstract: The first clinical application of intraaortic balloon pumps (IABP) in Taiwan was in 1976 to treat post-cardiotomy cardiogenic shock. It is now the most commonly used circulatory assist. From 1991 to 1995, 186 patients received IABP support with an overall mortality rate of 41.9%. The male patients had the best survival rate, 67%, after coronary artery bypass grafting. The first extracorporeal membrane oxygenation (ECMO) was in 1987 to treat intractable heart failure caused by severe acute rejection after heart transplantation. Because of poor outcome, patients only received ECMO sporadically during the past years. From November 1994 to November 1995, 30 patients received ECMO support with 50% of them eventually weaned from ECMO and 27% discharged. For short-term support or emergency rescue, ECMO was a good choice. When long-term support was required, the ventricular assist device (VAD) was a more suitable assist. One patient who received Thermedics VAD developed right heart failure and finally died of sepsis and multiple organ failure. VAD should be implanted before the secondary organ failure. The first successful clinical heart transplantation in Taiwan was performed on July 17, 1987. From 1991 to 1995, 102 patients underwent heart transplantation. The operative mortality was 3.9%, and the 1 and 5 year actuarial survival rates were 86 ± 3% and 77 ± 5%, respectively. To improve the success rate of clinical heart transplantation, organ donation should be encouraged.     

Novel multi-functional life support system

Concepts of cardiopulmonary support (CPS), extracorporeal membrane oxygenation (ECMO), and ventricular support (VS) have been thoroughly studied and refined. These perfusion adjuncts often require multiple devices, skill sets, and significant financial burden to purchase, maintain, deploy, and use. We describe a novel system that is rapidly deployable, user-friendly, portable, safe, and economical. Over a 1-year period we have used a multi-functional life support system (MLS) in the cardiac catheterization laboratory, cardiovascular intensive care unit, and cardiac surgical suites. Further, we have conducted multiple transports within the hospital and one to an alternate facility. Applications have included ECMO, cardiopulmonary resuscitation-supported cardiogenic shock, high risk percutaneous coronary intervention (PCI), valvuloplasty, right ventricular assist device transition to ECMO post cardiotomy, left ventricular assist device transition to ECMO, ventricular septal defect closure, and ECMO transition to conventional cardiopulmonary bypass (CPB). Duration of support has ranged from approximately 39 minutes to several days. Keywords: extracorporeal membrane oxygenation (ECMO), percutaneous ventricular assist device, cardiopulmonary support, portable cardiopulmonary life support, ventricular assist.     

Mechanical circulatory support for fulminant myocarditis

PURPOSE: Fulminant myocarditis is potentially fatal because it progresses rapidly into cardiogenic shock; thus, immediate and appropriate treatment is essential. Mechanical circulatory support (MCS) is an important part of treatment for fulminant myocarditis. We review our experience of treating fulminant myocarditis with MCS. METHODS: We used MCS with veno-arterial bypass (VAB) to treat seven patients with fulminant myocarditis. Five of these patients were younger than 18 years old. The mean time from arriving at our institution to the initiation of MCS was 15.9 +/- 22.6 h. MCS was initiated within 18 h in six patients. RESULTS: The mean assist time of MCS was 70.9 +/- 35.0 h and six patients were weaned successfully (weaning rate: 85.7%). The remaining patient required support with VAB for 132 h, and a left ventricular assist device was applied. All seven patients were weaned off MCS and discharged. CONCLUSIONS: Since severe and rapid hemodynamic compromise is typical of fulminant myocarditis, an immediate decision must be made about whether to initiate MCS. We attribute the excellent results and favorable long-term prognosis of our patients to the early initiation of MCS.     

Use of a ventricular assist device as a bridge to transplantation in a patient with single ventricle physiology and total cavopulmonary anastomosis

Mechanical circulatory support can be used to manage acute and chronic cardiac failure in both adult and pediatric patients. Traditionally, extracorporeal membrane oxygenation (ECMO) has been the most common form of mechanical circulatory support in children. However, more recently, in cases of pure ventricular dysfunction, ventricular assist devices (VADs) have offered specific advantages over ECMO, including better ventricular recovery, reduced anticoagulation requirements, decreased use of blood products and decreased cost. We present the use of a VAD in an adolescent with single-ventricle physiology, who could not be weaned from cardiopulmonary bypass (CPB) after undergoing a revision of a modified Fontan operation. Gas exchange was provided by the patient's lungs while the centrifugal VAD was used successfully to support the circulation as a bridge, first to a totally implantable pulsatile VAD and subsequently to heart transplantation.     

Total and prolonged filling of the lungs with Ringer's solution under extracorporeal lung assist (ECLA) in dogs

BACKGROUND: Massive alveolar lavage has been used clinically to remove materials accumulated in the alveoli. Recently, filling the lungs with oxygenated perfluorochemical (total liquid ventilation) has been investigated. However, effects of complete and prolonged filling of bilateral lungs with aqueous fluid, such as saline or Ringer's solution, has not been evaluated, although it is possible to sustain gas exchange without the natural lung by using extracorporeal circulation and an artificial lung (extracorporeal lung assist: ECLA). It is also not known whether the lung can recover gas exchange ability after prolonged fluid filling. METHODS: Normal mongrel dogs were endotracheally intubated under general anesthesia and mechanically ventilated. After initiation of venoarterial ECLA, warmed lactated Ringer's solution was instilled into the lungs through the endotracheal tube, and the lungs were completely filled at a hydrostatic pressure of 15 cmH2O (fluid-filled group: group F). After the lungs were filled for 4 h, the fluid was drained and ventilation was re-instituted. ECLA, then mechanical ventilation was gradually weaned within 24 h after fluid drainage. In control group (group C), dogs were kept apneic for 4 h with their lungs inflated at an airway pressure of 15 cmH2O with air. RESULTS: Transient hypoxemia occurred during fluid filling but every dog could be weaned from ECLA and mechanical ventilation to spontaneous respiration. The average rate of fluid absorption from the lung during fluid filling was 4.2+/-1.8 ml kg(-1) h(-1). After fluid drainage and restart of mechanical ventilation, bilateral lungs were expanded and well aerated. Total static respiratory system compliance (static compliance) remained unchanged even after fluid filling, and the weight of the lung water did not increase significantly compared to that in group C. Total urine volume was significantly increased in group E Histologically, alveolar structures were preserved and no interstitial edema or bleeding was seen in either group. CONCLUSION: Complete filling of the bilateral lungs for 4 h with lactated Ringer's solution under ECLA causes no deterioration in gas exchange or static compliance in normal dogs, although transient hypoxemia occurs during fluid filling.     

小儿体外膜肺氧合支持治疗8例

目的 总结小儿先天性心脏病术后严重心力衰竭和暴发型心肌炎应用体外膜肺氧合(ECMO)支持治疗的经验.方法 8例中术后不能脱离CPB 7例、暴发型心肌炎1例.均使用离心泵,全部静脉-动脉模式;采用中心插管、右房-升主动脉7例,周围大血管插管、股静脉-股动脉模式1例.辅助65～498 h,辅助流量80～120ml·min-1·kg-1.结果 死亡5例;出院3例,生存率38%.并发症包括出血5例、血栓形成2例、溶血1例、DIC 1例、肝衰竭1例、营养不良2例、机械故障2例.结论 先心病术后无残余解削畸形,而出现严重心衰病例,往往因合并左、右心室并伴肺功能不全,宜及时施行ECMO支持治疗,而取代肺脏气体交换功能,减少呼吸器使用中的高浓度氧气和气道压的肺损伤,降低总体病死率;注意及时补充新鲜血小板、血浆等血制品;合理应用血管活性药物和肝素,根椐出血部位及量采用针对性措施,维持内环境稳定;加用超滤,减少机体特别是出血的并发症.应选用长期使用的肝素涂层膜肺,监测膜前后压力,注意血浆渗漏,减少机械并发症.

Abstract：

Objective The use of extracorporeal membrane oxygenation (ECMO) as a treatment for the failure of cardiopulmonary function after cardiac surgery is increasing and has been reported to be 3% to 5% in the cases with congenital heart disease. We reviewed our experience with ECMO in children who received heart surgery for congenital heart disease and complicated with severe heart failure postoperatively. Methods Eight patients received ECMO, seven was due to the failure to wean from bypass and one had fulminant myocarditis. Import membrane oxygenator,veno-arterial mode ECMO and right atriumascending aortic cannulation were used in 7 cases and peripheral cannulation via femoral veno-artery route was used in 1 case.Supportive intervention persisted from 65 to 498 hours, with flow rate maintained at 80 to 120 ml per minute per kilogram body weight. Results Five patients died, with a mortality of 62.5%, and 3 cases discharged, with a survival rate of 38%. Bleeding occurred in 5 cases, thrombosis occurred in 2 cases, hemolysis was identified in 1 case and DIC was observed in 1 case.One case had liver failure and 2 cases had malnutrition. Oxygenator plasma leakage occurred in 2 cases. Mean arterial blood pressure increased significantly after the establishment of ECMO as compared with that before the procedure [( 60.2 ± 7.8 )mmHg vs. (48. 1 ± 5.2 ) mmHg, P≤0.05]. The arterial concentration of lactate decreased significantly, from (5. 1 ± 0. 8 )mmol per liter before ECMO to ( 3.6 ±0. 5 )mmol per liter after ECMO, P ＜0.05. Conclusion For patients who survived the congenital heart surgery and no residual anatomic deformity, ECMO can be used as early as possible as a treatment for severe heart failure which resulted from coexistent of left and right ventricular and pulmonary insufficiency. An overall mortality may be decreased by ECMO technique as it plays a substitution role for gas exchange in the lung. As a result, the concentration of oxygen and the airway pressure used during ventilation, and the resultant lung injury can be reduced. Appropriate strategies involve transfusion of fresh platelet and packed red blood cells, replacement of frozen plasma and blood products, as well as rational use of vasoactive drugs and heparin, and maintaining a stable internal environment. Following strategies are also recommended: using continuous arterio-venous hemofiltration and durable heparin-coated membrne oxygenator, reducing hemorrhagic complications, monitoring pressure on both side of the film, identifying plasma leakage carefully and reducing the mechanical complications.     

Outcomes of congenital heart surgery patients after extracorporeal life support at Texas Children's Hospital

The objective of this study was to investigate the outcomes of children with heart failure of various etiologies requiring temporary use of currently available technology in the U.S.A. after extracorporeal life support (ECLS) [left ventricular assist device (LVAD) or extracorporeal membrane oxygenation (ECMO)] at Texas Children's Hospital. Between July of 1995 and October of 2002, 2847 patients underwent congenital heart surgical repairs with the aid of cardiopulmonary bypass at Texas Children's Hospital. During this period, 17 patients required chronic mechanical circulatory assistance with Biomedicus centrifugal pump (n=8) or Thoratec LVAD (n=4), and ECMO (n=5). Six out of 17 patients required ECLS for postcardiotomy heart failure. Seven of the 17 patients had congenital heart disease, six had cardiomyopathy, three had late acute rejection following heart transplantation, and one had myocardial infarction. Twelve patients survived and five patients expired. Six of 12 survivors recovered sufficient cardiac function to allow device removal; and the remaining six patients underwent heart transplantation. Three out of five deaths were ECMO patients. The need for ECLS following repair of congenital heart disease is extremely rare in our institution. The requirement for the use of ECMO confers a significantly higher mortality presumably because of associated combined cardiopulmonary failure. Congenital heart disease appears to be associated with significantly higher mortality.     

Extracorporeal Life Support After Cardiac Surgery in Children: Outcomes From a Single Institution

Extracorporeal life support (ECLS) is used after congenital heart surgery for several indications, including failure to separate from cardiopulmonary bypass, postoperative low cardiac output syndrome, and extracorporeal cardiopulmonary resuscitation. Here, we assessed the outcomes of ECLS in children after cardiac surgery at our institution. Medical records of all children who required postoperative ECLS at our institution were reviewed. Between 2003 and 2011, 36 (1.4%) of 2541 pediatric cardiac surgical cases required postoperative ECLS. Median age of patients was 64 days (range: 0 days–4.1 years). ECLS was in the form of either extracorporeal membrane oxygenation (ECMO; n = 24) or ventricular assist system (VAS; n = 12). Mean duration of ECLS was 4.9 ± 4.2 days. Overall, 21 patients (58%) were weaned off ECLS, and 17 patients (47%) were successfully discharged from the hospital. Patients with biventricular heart (BVH) had higher survival‐to‐hospital discharge rates compared with those with univentricular heart (UVH) (P = 0.019). Regarding ECLS type, UVH patients who received VAS showed higher rates of device discontinuation than UVH patients who received ECMO (P = 0.012). However, rates of hospital discharge were not significantly different between UVH patients who received VAS or ECMO. Surgical interventions, such as banding of Blalock–Taussig shunt to reduce pulmonary blood flow or placing bidirectional cavopulmonary shunt to minimize ventricular volume overload, were effective for weaning off ECLS in patients with UVH. ECLS is beneficial to children with low cardiac output after cardiac surgery. Rates of survival‐to‐hospital discharge were higher in BVH patients than UVH patients. Additional interventions to reduce ventricular volume load may be effective for discontinuing ECLS in patients with UVH.     

Cytokine Generation in Rabbits During Extracorporeal Lung Assist with a Mini Hollow Fiber Lung

Abstract: To examine host responses to extracorporeal lung assist (ECLA) in small animals, we developed a mini hollow fiber lung of nonmicroporous polyolefin and an extracorporeal bypass circuit with a priming volume of 25 ml. This circuit allowed ECLA of up to 72 h without blood transfusion in 20 rabbits. The ECLA procedure induced the appearance of tumor necrosis factor-a (TNF-a) and interleukin-1 (IL-1) receptor antagonist (IL-IRa) in plasma, but not IL-ip. However, these changes were observed only at the initial stage of ECLA, and the levels returned to pre-ECLA levels within 24 h. Although leukocytes adhering to the hollow fibers were immunohisto-chemically positive for IL-ip and IL-IRa, the plasma levels of these cytokines in response to ECLA were not different from those observed in rabbits given anesthesia and subjected to minor surgery but without ECLA. Thus, ECLA itself is a minor factor in the production of these cytokines.     

Extracorporeal life support during and after bilateral sequential lung transplantation in patients with pulmonary artery hypertension

The use of extracorporeal membrane oxygenator instead of standard cardiopulmonary bypass during lung transplantation is debatable. Moreover, recently, the concept of prolonged postoperative extracorporeal membrane oxygenator (ECMO) support has been introduced in many transplant centers to prevent primary graft dysfunction (PGD) and improve early and long-term results. The objective of this study was to review the results of our extracorporeal life support strategy during and after bilateral sequential lung transplantation (BSLT) for pulmonary artery hypertension. We review retrospectively our experience in BSLT for pulmonary artery hypertension between January 2010 and August 2018. A total of 38 patients were identified. Nine patients were transplanted using cardiopulmonary bypass (CPB), in eight cases CPB was followed by a prolonged ECMO (pECMO) support, 14 patients were transplanted on central ECMO support, and seven patients were transplanted with central ECMO support followed by a pECMO assistance. The effects of different support strategies were evaluated, in particular in-hospital morbidity, mortality, incidence of PGD, and long-term follow-up. The use of CPB was associated with poor postoperative results and worse long-term survival compared with ECMO-supported patients. Predictive preoperative factors for the need of intraoperative CPB instead of ECMO were identified. The pECMO strategy had a favorable effect to mitigate postoperative morbidity and mortality, not only in intraoperative ECMO-supported patients, but even in CPB-supported cases. In our experience, ECMO may be considered as the first choice circulatory support for lung transplantation. Sometimes, in very complex cases, CBP is still necessary. The pECMO strategy is very effective to reduce incidence of PGD even in CPB-supported patients.     

Experimental evaluation of the V-point heparin-bonding system applied to a dense-membrane artificial lung during 24-hour extracorporeal circulation in beagles

Heparin was covalently bonded to a hollow-fiber dense-membrane artificial lung and circuit using a silane coupling agent and polyethyleneimine as a spacer. This study investigated whether the novel artificial lung could sustain prolonged extracorporeal lung assist (ECLA) by venoarterial bypass in beagles using minimal anticoagulants. We maintained ECLA for 24 h in 3 groups of minimal systemic heparinization, heparinization with the new anticoagulant nafamostat mesilate, and without any systemic anticoagulant. The results were assessed from the functional performance of the artificial lung and by macroscopic and microscopic examination after the experiments. Artificial lung function, hemodynamics, hemogram, and platelet aggregation activity were well maintained in all groups. There was no plasma leakage from the artificial lung. Although several clots were observed in stagnant areas of the artificial lungs and circuits, there was no clot formation inside the artificial lung in any group. This highly biocompatible, heparin-bonded dense-membrane artificial lung performed well and safely during prolonged ECLA with blood clotting times less than 120 s.     

A Simple Left Heart Assist Device For Use After Intracardiac Surgery: Development, Deployment and Clinical Experience

A simple left heart assist device (LHAD) has been developed and employed in nineteen patients with severe left ventricular dysfunction who could not be weaned from cardiopulmonary bypass following intracardiac surgery. It has been used when all other means of weaning, including maximum pharmacologic therapy and intra-aortic balloon counterpulsation (IABC), had failed. The device utilizes specially designed and constructed obturated cannulae in the left atrium and the ascending aorta, and an extracorporeal roller pump to partially bypass the left ventricle. With improved cardiac performance, the patient may be separated from the device without need for thoracic reentry.
Of the nineteen patients having LHAD support (2–500 hours), thirteen were eventually weaned from the device and seven were discharged from the hospital. Five patients remain alive and well (18 to 50 months postoperatively).     

To-and-fro extracorporeal lung assist (ECLA) through a single catheter — in premature goats as an experimental model of infant respiratory insufficiency

A new to-and-fro V-V bypass extracorporeal lung assist (ECLA) through a single catheter as a blood access was investigated for its efficacy on six premature goats delivered by Cesarean section at a gestational age of 118 139 days as an experimental model of infant respiratory insufficiency, then applied to a human premature infant suffering from life threatening barotrauma that had developed from mechanical pulmonary ventilation. The extracorporeal bypass flow and the gas flow to the artificial membrane lung were controlled to keep Pa_{O 2} above 40mmHg and Pa_{CO 2} within normal limits. The neonates own lungs were treated with a continuous positive airway pressure of 5 12cmH₂O, apneic oxygenation or IMV. Two goats weighing 1250g and 700g died 2 2.5 hours after birth from severe circulatory distress. However, the other four neonates which were heavier than 2000g, were successfully weaned from ECLA, and three of these could be weaned from mechanical ventilation as well. A human infant also survived and was weaned from ECLA on the third day.(Tanoue T, Terasaki H, Sadanaga M et al.: To-and-fro extracorporeal lung assist (ECLA) through a single catheter-in premature goats as an experimental model of infant respiratory insufficiency. J Anesth 2: 124–132, 1988)     

Extracorporeal membrane oxygenation support for adult postcardiotomy cardiogenic shock

BACKGROUND: Postcardiotomy cardiogenic shock occasionally develops in patients who have undergone cardiac procedures. We report our experience using extracorporeal membrane oxygenation (ECMO) in adult patients with postcardiotomy cardiogenic shock, and analyze the factors that affected outcomes for these ECMO patients. METHODS: We retrospectively reviewed the medical records of ECMO patients. RESULTS: From August 1994 to May 2000, 76 adult patients (48 men, 28 women; mean age, 56.8+/-15.9 years) received ECMO support for postcardiotomy cardiogenic shock at the National Taiwan University Hospital. The mean ECMO blood flow was 2.53+/-0.84 L/min. The cardiac operations included coronary artery bypass grafting (n = 37), coronary artery bypass grafting and valvular operation (n = 6), valvular operation alone (n = 14), heart transplantation (n = 12), correction of congenital heart defects (n = 3), implantation of a left ventricular assist device (n = 2), and aortic operations (n = 2). Fifty-four patients received ECMO support after intraaortic balloon pumping, but 22 patients directly received ECMO support. Two patients were bridged to heart transplantation and two bridged to ventricular assist devices. Thirty patients died on ECMO support. The causes of mortality included brain death (n = 3), refractory arrhythmia (n = 2), near motionless heart (n = 2), acute graft rejection (n = 1), primary graft failure (n = 1), uncontrolled bleeding (n = 5), and multiple organ failure (n = 16). Twenty-two patients were weaned off ECMO support but presented intrahospital mortality. The cause of mortality included brain death (n = 1), sudden death (n = 4), and multiple organ failure (n = 17). Twenty patients were weaned off ECMO support and survived to hospital discharge. During the follow-up of 33+/-22 months, all were in New York Heart Association functional status I or II except two cases of late deaths. Among the ECMO-weaned patients, "dialysis for acute renal failure" was a significant factor in reducing the chance of survival. CONCLUSIONS: The ECMO provided a satisfactory partial cardiopulmonary support to patients with postcardiotomy cardiogenic shock, and allowed time for clinicians to assess the patients and make appropriate decisions.