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.     

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

Extracorporeal membrane oxygenation (ECMO) is being increasingly used in patients having sepsis-induced cardiovascular dysfunction. We report successful use of venovenous ECMO in septic shock secondary to pneumonia in the presence of severe left ventricular dysfunction. We also discuss the quantitative evaluation of cardiovascular dysfunction, which provides important input in choosing the type of ECMO in septic shock.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12055-020-01119-4.     

The early evaluation of survivors after extracorporeal membrane oxygenation for neonatal pulmonary failure

Excluding mortality data, there is little information regarding patients' development after extra corporeal membrane oxygenation (ECMO). In six of nine neonates surviving ECMO for predictably fatal pulmonary failure, examination 15 to 21 months afterward showed (1) physical growth and development, normal in six; (2) chest x-ray, normal pulmonary parenchyma; (3) average arterial blood gases, PO2 80, Pco2 35, pH 7.35; (4) echocardiogram, normal, without evidence of pulmonary hypertension; (5) cerebrovascular dopplers, normal ophthalmic artery flow in five patients, retrograde in one; (6) CT scan, EEG, neurologic survey, normal in five, cerebral atrophy in one patient who had an air embolus during decannulation; (7) psychologic examination, normal in all. This early evaluation of ECMO survivors should encourage its further application in those newborns who would otherwise die.     

Evaluating cannulation strategies used during second courses of extracorporeal membrane oxygenation in a large cohort of pediatric patients

Purpose

After a successful course of extracorporeal membrane oxygenation (ECMO), patients can deteriorate and a second ECMO course may be contemplated. When a second ECMO course becomes necessary in pediatric patients, survival rates comparable to the first ECMO course are possible. The perceived difficulties involved in recannulation after an initial ECMO course can prevent clinicians from reliably offering a second ECMO run to an eligible pediatric patient. We hypothesized that national ECMO registry data could provide cannulation templates for pediatric patients requiring a second ECMO course.

Methods

We obtained data from the Extracorporeal Life Support Organization registry (1981-2007) on patients 1 to 18 years old who required single-run ECMO (SRE) or multiple-run ECMO (MRE). Primary outcome measures were complications and survival. Cannulation-specific variables were compared using χ² methods (Fisher exact, McNemar's). Statistical significance was assumed at P < .05.

Results

A total of 3810 (96.8%) children underwent SRE and 127 (3.2%) required MRE. Survival was similar in both groups (49% vs 44%; P = .28). Cannulation data were available in 2539 SRE (67%) and 88 MRE (69%) cases. Compared with SRE, first ECMO courses in MRE patients consisted of fewer cervical (52.3% vs 71.7%; P < .001) but more femoral (20.5% vs 10.7%; P = .01) and central (27.3% vs 17.6%; P = .02) cannulations. In MRE patients, central cannulation was more frequent in second vs first ECMO courses (43.0% vs 27.3%; P = .03). Multiple-run ECMO survival was unaffected by cannulation strategy. Multiple-run ECMO patients with unchanged cannulation sites between first and second ECMO courses had fewer total complications than those requiring new cannulation sites (3.7 vs 5.1; P = .04).

Conclusions

Second ECMO courses in pediatric patients can achieve survival comparable to the first course, but more often require central cannulation. Reusing cannulation sites for a second ECMO course is associated with fewer total complications than cannulating at new sites. These data provide guidance when considering cannulation strategies for second ECMO courses in pediatric patients.     

体外膜式氧合相关并发症分析

目的 分析体外膜式氧合(ECMO)辅助过程中相关并发症情况,以期对提高ECMO辅助抢救成功率.方法 回顾2005年3月至2008年6月117例接受ECMO辅助者的临床资料,其中静脉-静脉转流2例,静脉-升主动脉转流5例,股静脉-股动脉转流110例.结果 ECMO平均辅助时间61h.死亡48例,病死率41.0%.74例治疗过程中发生各种并发症,发生率为63.2%.主要并发症为感染32例次、肾功能衰竭需要透析29例次、氧合器血浆渗漏29例次、二次开胸止血24例次潲化道出血14例次、溶血7例次、肢体血栓5例次、神经系统并发症4例次、离心泵故障1例次.结论 出血是ECMO早期最常见的并发症,随辅助时间延长,感染、肾功能衰竭及氧合器血浆渗漏等并发症明显增加.积极预防、治疗并发症对提高ECMO病人抢救成功率非常重要.     

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.     

体外膜肺氧合治疗幸存患者生活质量研究进展

综述接受体外膜肺氧合治疗幸存患者的生活质量现状、影响因素、干预手段。目前体外膜肺氧合治疗幸存患者生活质量不佳,受多种因素影响。医护人员应提高对该人群的重视,探索有效改善其生活质量的干预方法。     

Venovenous extracorporeal membrane oxygenation during high-risk airway interventions

 Open in a separate windowOBJECTIVESPractice patterns for the use of extracorporeal membrane oxygenation (ECMO) during high-risk airway interventions vary, and data are limited. We aim to characterize our recent experience using ECMO for procedural support during whole-lung lavage (WLL) and high-risk bronchoscopy for central airway obstruction (CAO).METHODSWe performed a retrospective cohort study of adults who received ECMO during WLL and high-risk bronchoscopy from 1 July 2018 to 30 March 2020. Our primary end point was successful completion of the intervention. Secondary end points included ECMO-associated complications and hospital survival.RESULTSEight patients received venovenous ECMO for respiratory support during 9 interventions; 3 WLLs for pulmonary alveolar proteinosis were performed in 2 patients, and 6 patients underwent 6 bronchoscopic interventions for CAO. We initiated ECMO prior to the intervention in 8 cases and during the intervention in 1 case for respiratory decompensation. All 9 interventions were successfully completed. Median ECMO duration was 17.8 h (interquartile range, 15.9–26.6) for the pulmonary alveolar proteinosis group and 1.9 h (interquartile range, 1.4–8.1) for the CAO group. There was 1 cannula-associated deep vein thrombosis; there were no other ECMO complications. Seven patients (87.5%) and 4 (50.0%) patients survived to discharge and 1 year postintervention, respectively.CONCLUSIONSUse of venovenous ECMO to facilitate high-risk airway interventions is safe and feasible. Planned preprocedural ECMO initiation may prevent avoidable respiratory emergencies and extend therapeutic airway interventions to patients otherwise considered too high-risk to treat. Guidelines are needed to inform the utilization of ECMO during high-risk bronchoscopy and other airway interventions.     

Systemic hypertension associated with venovenous extracorporeal membrane oxygenation for pediatric respiratory failure

Background/purpose

Arterial hypertension (HTN) is common in neonates on venoarterial (VA) extracorporeal membrane oxygenation (ECMO), but HTN in pediatric venovenous (VV) ECMO has not been well described. The authors noted HTN in their VV ECMO experience and hypothesized that HTN was associated with fluid status, steroid use, and renal insufficiency.

Methods

Records of 50 patients receiving VV ECMO for respiratory failure were reviewed. HTN was defined as systolic blood pressure greater than 95th percentile for age for ≥1 hour, unresponsive to sedation/analgesia. Hypertensive index (HI) is defined as total hypertensive hours per total ECMO hours. Fluid status was estimated by a fluid index (FI = total fluid balance during ECMO per ECMO hours per weight).

Results

Forty-seven of 50 patients (94%) had HTN. Median HI was 0.21 (range, 0.01 to 1.0). Thirteen patients had renal insufficiency, 39 received steroids, and 23 received continuous venovenous hemofiltration (CVVH). There was no association between HI and FI, steroid use, or renal insufficiency. Thirty-three patients were treated for HTN, often requiring multiple agents. Bleeding complicated the course of 18 patients, and HI was significantly higher in those patients (P = .03). HI was not different between survivors (37 of 39 with HTN) and nonsurvivors (10 of 11 with HTN).

Conclusions

Hypertension is a common complication associated with VV ECMO with unclear etiology. HTN was frequently difficult to control. This study emphasizes the need for the development of treatment protocols to decrease the incidence, severity, and associated morbidity. Improved insight into the etiology of HTN associated with pediatric VV ECMO, including evaluation of the renin-angiotensin system, would help guide therapy.     

Surgical aspects of pediatric cardiac extracorporeal membrane oxygenation

Because children with severe myocardial dysfunction have limited therapeutic options, mechanical support of a failing heart is a matter of great interest. In the setting of cardiogenic shock or severe low cardiac output and hypoperfusion, extracorporeal membrane oxygenation (ECMO) can produce decisive improvements. The criteria for successful treatment include appropriate patient selection, improved surgical techniques and experience, higher recognition and anticipation of complications, and minimized delay in initiation of ECMO. Because the need for mechanical circulatory support may arise pre-, intra-, and postoperatively, every pediatric cardiac surgeon must be familiar with the principles and the surgical aspects of ECMO.     

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.     

Coagulation and anticoagulation in extracorporeal membrane oxygenation

The hemostatic system poses a major problem in extracorporeal membrane oxygenation (ECMO). The foreign surface in the extracorporeal circuit activates platelets and the clotting system. To avoid loss of platelets and activation of the clotting system, anticoagulation is necessary. In addition, in many patients on ECMO, preexisting clotting disorders are present. Therefore, bleeding and/or thrombosis are frequent complications in ECMO patients that require specific treatment and may even necessitate termination of ECMO. Most ECMO centers use heparin for anticoagulation and the activated clotting time (ACT) for monitoring. Reduction of problems with hemostasis may be obtained with less thrombogenic surfaces, new anticoagulants with a short half-life, platelet inhibitors, protease inhibitors, or selective anticoagulation in the extracorporeal circuit. While there will probably never be a complete nonthrombogenic surface available and all anticoagulants will have some risk of bleeding, improvement can be obtained by a combination of measures including better surfaces, more sophisticated anticoagulation regimens, and close laboratory monitoring.     

Repair of traumatic avulsion of the right bronchus in children using extracorporeal membrane oxygenation support

Traumatic avulsion of the right main bronchus in children is usually caused by blunt trauma or traffic accidents. Primary repair by suturing is the preferred treatment. Lesions are life threatening and urgent or emergency surgical repair is indicated. We report our experience with 2 cases of traumatic avulsion of right bronchus in children successfully suture repaired with the use of extracorporeal membrane oxygenation.     

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.     

An established extracorporeal membrane oxygenation protocol promotes survival in extreme hypothermia

Background

Historical reports indicate that active rewarming with extracorporeal membrane oxygenation (ECMO) can salvage a patient after hypothermic cardiac arrest. We created a protocol that includes ECMO for extreme hypothermia to guide rewarming of the hypothermic patient.

Methods

A retrospective review of the ECMO rewarming protocol (2004-2006) was conducted.

Results

The active rewarming protocol is a flowchart that is available on our hospital intranet and can be accessed in the trauma bay. A severely hypothermic patient triggers the activation of a TRAUMA ONE-OP ECMO response. During the 2-year period, there were 5 activations of the system and 4 children were placed on ECMO. Two of the 4 were dramatically salvaged and eventually discharged neurologically intact. All 5 children were found pulseless at the scene before transport. The average time from the injury occurrence to arrival was 94 minutes (range, 41-181 minutes). Mean cardiopulmonary resuscitation time was 78.2 minutes (range, 37-152 minutes). The mean core temperature on arrival was 25.4°C (range, 20.4°C-28.6°C). The average time from arrival to ECMO cannulation was 25.5 minutes (range, 16-37 minutes).

Conclusion

A preemptive strategy for the severely hypothermic patient provides an organized approach and prompt response. Expeditious rewarming can make the difference in an opportunity for survival.     

成人体外膜肺氧合循环支持19例

目的总结成人临床应用体外膜肺氧合（ECMO）的经验、教训。方法2004年12月至2006年4月对19例成人实施ECMO，男14例，女5例；年龄19～72岁，平均48．8岁；体重37～100kg，平均69．2kg。内科急性心肺衰竭4例，术后心肺衰竭15例。使用Medtmnic成人ECMO配套系统，经股动、静脉插管行心肺辅助。结果10例（52．6％）顺利出院，9例（47．4％）死亡，其中6例未能脱机，EC2V10成功脱机13例（68．4％），其中3例脱机后未能得到进一步有效治疗而死亡。EC2V10支持11～196h，平均83．3h。单一膜肺使用寿命40～134h。结论EC2V10可以作为临床难治性心肺衰竭的有效辅助手段，使危重症病人度过危险期，为进一步治疗争取宝贵的时间。     

Early repair of congenital diaphragmatic hernia on extracorporeal membrane oxygenation

Background

Timing of repair of congenital diaphragmatic hernia (CDH) in babies that require stabilization on extracorporeal membrane oxygenation (ECMO) remains controversial. Although many centers delay operation until physiologic stabilization has occurred or ECMO is no longer needed, we repair soon after ECMO has been initiated. The purpose of this study is to determine if our approach has achieved acceptable morbidity and mortality.

Methods

Charts of live-born babies with CDH treated at our institution between 1993 and 2007 were retrospectively reviewed. Data were then compared with The Congenital Diaphragmatic Hernia Study Group and Extracorporeal Life Support Organization registries.

Results

Forty-eight (39%) patients required ECMO Thirty-four of these 48 neonates were cannulated before operative repair. Venoarterial ECMO was used exclusively. The mean (SD) time of repair from cannulation was 55 (21) hours. Survival for this subset of patients was 71%. Three patients (8.8%) who underwent repair on ECMO experienced surgical site hemorrhage that required intervention.

Conclusion

Early repair of CDH in neonates on ECMO can be accomplished with acceptable rates of morbidity and mortality.     

Issues of pharmacology in pediatric cardiac extracorporeal membrane oxygenation with special reference to analgesia and sedation

Sufficient analgesia, sedation, and paralysis, if necessary, are cornerstones of extracorporeal membrane oxygenation (ECMO) treatment protocols. However, increased distribution volumes, drug absorption by circuit materials, and impaired drug elimination, as well as alternations of cerebral perfusion and blood brain barrier function, result in the markedly altered pharmacodynamics of applied drugs. Today, narcotics combined with benzodiazepines, sometimes enforced by barbiturates, are commonly used in clinical practice. Paralysis is usually achieved by pancuronium or vecuronium. Although these drugs are used widely, actual efficacy remains uncertain because of the lack of reliable tools to measure pain relief and degree of sedation during ECMO, especially during paralysis. Taking into account the detrimental effects of insufficient pain relief and inadequate sedation in such unstable patients as children during pediatric cardiac ECMO, further studies on this topic seem urgently necessary.     

婴幼儿颈部通路体外膜肺氧合相关性出血并发症分析

目的研究婴幼儿颈部通路体外膜肺氧合（ECMO）所致出血并发症及转归。 方法回顾性分析2009年9月至2021年1月期间在中山市人民医院行颈动静脉插管ECMO治疗的21例婴幼儿临床资料。观察ECMO运行期间和撤机后血小板、凝血功能和出血并发症情况。 结果ECMO建立后血小板计数明显下降,活化部分促凝血酶原激活时间（APTT）和活化全血凝固时间（ACT）快速升高,差异均有统计学意义（P<0.05）。出血并发症发生率为61.90%（13/21）,包括颈部切口出血8例（38.10%）、肺出血7例（33.33%）、消化道出血5例（23.81%）、颅内出血3例（14.29%）、泌尿系统出血2例（9.52%）。出血组死亡率为38.46%（5/13）,无出血组死亡率为25.00%（2/8）。 结论婴幼儿颈部通路ECMO相关出血并发症较多。颅内出血在上机期间影响患儿生存,但撤机后基本可以恢复正常,无严重后遗症。     

体外膜肺氧合在肺移植前支持过渡中的应用

目的 探讨体外膜肺氧合(extracorporeal membrane oxygenation,ECMO)在肺移植前支持过渡中应用的可行性和疗效.方法 终末期肺病患者5例,原发病为特发性肺间质纤维化3例,结核性毁损肺1例,淹溺致吸入性肺炎合并急性呼吸窘迫综合征(ARDS)1例.药物治疗和呼吸机无法纠正呼吸衰竭,紧急行E...