Rapid cardiopulmonary support for children with complex congenital heart disease

Mechanical circulatory support in paediatric population

Extra-corporeal membrane oxygenation is a life-saving modality to support the cardiac and/or pulmonary system as a form of life support in resuscitation, post-cardiotomy, as a bridge to cardiac transplantation and in respiratory failure. Its use in the paediatric and neonatal population has proven incredibly useful. However, extra-corporeal membrane oxygenation is also associated with a greater rate of mortality and complications, particularly in those with co-morbidities. As a result, interventions such as ventricular assist devices have been trialled in these patients. In this review, we provide a comprehensive analysis of the current literature on extra-corporeal membrane oxygenation for cardiac support in the paediatric and neonatal population. We evaluate its effectiveness in comparison to other forms of mechanical circulatory support and focus on areas for future development.

Pediatric ventricular assist devices: what are the key considerations and requirements?

Introduction: The development of ventricular assist devices (VADs) have enabled myocardial recovery and improved patient survival until heart transplantation. However, device options remain limited for children and lag in development.Areas covered: This review focuses on the evolution of pediatric VADs in becoming to be an accepted treatment option in advanced heart failure, discusses the classification of VADs available for children, i.e. types of pumps and duration of support, and defines implantation indications and explantation criteria, describes attendant complications and long-term outcome of VAD support. Furthermore, we emphasize the key considerations and requirements in the application of these devices in infants, children and adolescents.Expert opinion: Increasing use of VADs has facilitated a leading edge in management of advanced heart failure either as a bridge to transplantation or as a bridge to myocardial recovery. In newborns and small children, the EXCOR Pediatric VAD remains the only reliable option. In some patients ventricular unloading may lead to complete myocardial recovery. There is a strong need for pumps that are fully implantable, suitable for single ventricle physiology, such as the right ventricle.

Outcomes of early versus delayed initiation of extracorporeal life support in cardiac surgery

Background

Extracorporeal membrane oxygenation offers temporary hemodynamic support for patients with refractory cardiogenic shock after cardiovascular surgery. However, the initiation time for such patients is controversial. Changing the initiation time might improve the outcomes. This study aimed to investigate whether early extracorporeal membrane oxygenation could improve postoperative outcomes in patients at a high risk of cardiogenic shock.

Methods

In this retrospective study, 173 patients with cardiovascular diseases at a high risk of refractory cardiogenic shock which assessed via empirical risk evaluation from 2010 to 2017 were included. After propensity matching, 36 patients, who were matched to patients initiated with extracorporeal membrane oxygenation after cardiovascular operation (delayed extracorporeal membrane oxygenation group, n = 36), were also initiated with such early in the operating room (early extracorporeal membrane oxygenation group, n = 36). The primary outcome was death. The secondary outcomes included receiving continuous renal replacement therapy, ventricular arrhythmia, and pulmonary infection.

Results

The demographic and baseline variables were similar between the matched groups. The early extracorporeal membrane oxygenation group showed lower mortality (69.44% vs 41.67%, P = 0.03), pulmonary infection morbidity (86.11% vs 55.56%, P < 0.01), and continuous renal replacement therapy rate(88.89% vs 66.67%, P = 0.04). Moreover, they showed improved cardiac index (P = 0.01) and lactate clearance (P < 0.01).

Conclusions

Extracorporeal membrane oxygenation provides effective support for cardiogenic failure refractory to medical management; early initiation improves cardiac output and promotes lactate clearance, thus increasing survival in patients with cardiogenic shock after cardiovascular surgery.

Trial registration

This is a retrospective study. It was not registered.

Eighteen years of paediatric extracorporeal membrane oxygenation and ventricular assist devices: insight regarding late outcomes

BACKGROUND

We reviewed all patients who were supported with extracorporeal membrane oxygenation and/or ventricular assist device at our institution in order to describe diagnostic characteristics and assess mortality.

METHODS

A retrospective cohort study was performed including all patients supported with extracorporeal membrane oxygenation and/or ventricular assist device from our first case (8 October, 1998) through 25 July, 2016. The primary outcome of interest was mortality, which was modelled by the Kaplan-Meier method.

RESULTS

A total of 223 patients underwent 241 extracorporeal membrane oxygenation runs. Median support time was 4.0 days, ranging from 0.04 to 55.8 days, with a mean of 6.4±7.0 days. Mean (±SD) age at initiation was 727.4 days (±146.9 days). Indications for extracorporeal membrane oxygenation were stratified by primary indication: cardiac extracorporeal membrane oxygenation (n=175; 72.6%) or respiratory extracorporeal membrane oxygenation (n=66; 27.4%). The most frequent diagnosis for cardiac extracorporeal membrane oxygenation patients was hypoplastic left heart syndrome or hypoplastic left heart syndrome-related malformation (n=55 patients with HLHS who underwent 64 extracorporeal membrane oxygenation runs). For respiratory extracorporeal membrane oxygenation, the most frequent diagnosis was congenital diaphragmatic hernia (n=22). A total of 24 patients underwent 26 ventricular assist device runs. Median support time was 7 days, ranging from 0 to 75 days, with a mean of 15.3±18.8 days. Mean age at initiation of ventricular assist device was 2530.8±660.2 days (6.93±1.81 years). Cardiomyopathy/myocarditis was the most frequent indication for ventricular assist device placement (n=14; 53.8%). Survival to discharge was 42.2% for extracorporeal membrane oxygenation patients and 54.2% for ventricular assist device patients. Kaplan-Meier 1-year survival was as follows: all patients, 41.0%; extracorporeal membrane oxygenation patients, 41.0%; and ventricular assist device patients, 43.2%. Kaplan-Meier 5-year survival was as follows: all patients, 39.7%; extracorporeal membrane oxygenation patients, 39.7%; and ventricular assist device patients, 43.2%.

CONCLUSIONS

This single-institutional 18-year review documents the differential probability of survival for various sub-groups of patients who require support with extracorporeal membrane oxygenation or ventricular assist device. The indication for mechanical circulatory support, underlying diagnosis, age, and setting in which cannulation occurs may affect survival after extracorporeal membrane oxygenation and ventricular assist device. The Kaplan-Meier analyses in this study demonstrate that patients who survive to hospital discharge have an excellent chance of longer-term survival.

Pediatric Mechanical Circulatory Support

Over the past two decades clinicians and researchers have sought to bring mechanical circulatory support (MCS) to pediatric patients with heart failure. ECMO, IABPs, and VADs have all been used in infants and children as a bridge to myocardial recovery or as a bridge to transplant. However, until recently, a commitment by industry, government, and researchers towards the development of pediatric MCS has not been present, especially in the United States. Advancements in adult VAD design to smaller, quieter, and fully implantable pumps capable of complete outpatient support have sparked curiosity in the application of this technology to children. Also, the increasing success of palliating congenital heart disease is creating an ever-growing cohort of children and adolescents with heart failure. These changing demographics and technological advances have caused a refocus of attention. This is most clearly demonstrated by the international use of several established MCS pediatric and neonatal systems, by the FDA's increasing proclivity to allow the use of international pediatric VADs in the USA, and by the recent National Heart, Lung, and Blood Institute funding of several institutions to develop pediatric VADs. This review describes the different aspects of pediatric MCS including indications, the features of the various VADs, and their current application in children worldwide.

Post-cardiotomy Rescue Extracorporeal Cardiopulmonary Resuscitation in Neonates with Single Ventricle After Intractable Cardiac Arrest: Attrition After Hospital Discharge and Predictors of Outcome

Extracorporeal cardiopulmonary resuscitation (ECPR) in children with cardiac arrest refractory to conventional cardiopulmonary resuscitation (CPR) has been reported with encouraging results. We reviewed outcomes of neonates with functional single ventricle (FSV) surviving post-cardiotomy ECPR after hospital discharge. Fifty-eight patients who required post-cardiotomy extracorporeal membrane oxygenation (ECMO) since the introduction of our ECPR protocol (January 2007-December 2011) were identified. Forty-one were neonates. Survival analysis was conducted. Of 41 neonates receiving post-cardiotomy ECMO, 32 had FSV. Twenty-one had ECPR. Fourteen underwent Norwood operation (NO) for hypoplastic left heart syndrome (HLHS). Seven had non-HLHS FSV. Four (of 7) underwent modified NO/DKS with systemic-to-pulmonary shunt (SPS), 2 SPS only and 1 SPS with anomalous pulmonary venous connection repair. Mean age was 6.8 ± 2.1 days. ECMO median duration was 7 days [interquartile range (IQR_25-75: 4-18)]. Survival to ECMO discontinuation was 72% (15 of 21 patients) and at hospital discharge 62% (13 of 21 patients). The most common cause of late attrition was cardiac. At last follow-up (median: 22 months; IQR_25-75: 3-36), 47% of patients were alive. Duration of ECMO and failure of lactate clearance within 24 h from ECMO deployment determined late survival after hospital discharge (p < 0.05). Rescue post-cardiotomy ECMO support in neonates with FSV carries significant late attrition. ECMO duration and failure in lactate clearance after deployment are associated with unfavorable outcome. Emphasis on CPR quality, refinement of management directives early during ECMO and aggressive early identification of patients requiring heart transplantation might improve late survival.

Extracorporeal Life Support in Pediatric and Neonatal Critical Care: A Review

Extracorporeal life support (ECLS) is a modified form of cardiopulmonary bypass used to provide prolonged tissue oxygen delivery in patients with respiratory and/or cardiac failure. The first large-scale success of ECLS was achieved in the management of term newborns with respiratory failure. ECLS has become an accepted therapeutic modality for neonates, children, and adults who have failed conventional therapy and in whom cardiac and/or respiratory insufficiency is potentially reversible. The use of ECLS allows one to reduce other cardiopulmonary supports and apply a gentle ventilation strategy in a population of severely compromised critical care patients. ECLS has now been employed in more than 26,000 neonatal and pediatric patients with an overall survival rate of 68%. ECLS has evolved significantly over 25 years of clinical practice; patient selection for this complex and highly invasive therapy, as well as how ECLS is employed in different patient groups, is constantly changing. Generally, ECLS is used more liberally now than in the past. The number of patients requiring this support, however, is declining yearly, and those patients who receive ECLS compose a more severe subset of an intensive care population. This review provides an overview of the development of ECLS and the equipment and techniques employed. The use of ECLS for neonatal respiratory failure, pediatric respiratory failure, and cardiac support are outlined. Management of the ECLS patient is discussed in detail, and outcome of these patients is reviewed. Finally, current trends and future implications of ECLS in neonatal and pediatric critical care are addressed.

Outcomes before and after implementation of a pediatric rapid-response extracorporeal membrane oxygenation program

BACKGROUND

Rapid-response extracorporeal membrane oxygenation (RR-ECMO) has been implemented at select centers to expedite cannulation for patients placed on ECMO during extracorporeal cardiopulmonary resuscitation (ECPR). In 2008, we established such a program and used it for all pediatric venoarterial ECMO initiations. This study was designed to compare outcomes before and after program implementation.

METHODS

Between 2003 and 2011, 144 pediatric patients were placed on venoarterial ECMO. Records of patients placed on ECMO before (17 ECPR and 62 non-ECPR) or after (14 ECPR and 51 non-ECPR) RR-ECMO program implementation were retrospectively compared.

RESULTS

The peak performance of the ECMO team was assessed by measuring ECMO initiation times for the ECPR patient subgroup (n = 31). There was a shift toward more ECPR initiations achieved in less than 40 minutes (24% pre-RR-ECMO versus 43% RR-ECMO; p = 0.25) and fewer requiring more than 60 minutes (47% pre-RR-ECMO versus 21% RR-ECMO; p = 0.14) after program implementation, although these changes did not reach statistical significance. After multivariable risk adjustment, RR-ECMO was associated with a 52% reduction in neurologic complications for all patients (adjusted odds ratio, 0.48; 95% confidence interval, 0.23 to 0.98; p = 0.04), but the risk of in-hospital death remained unchanged (adjusted odds ratio, 0.99; 95% confidence interval, 0.50 to 1.99; p = 0.99).

CONCLUSIONS

Implementation of a pediatric RR-ECMO program for venoarterial ECMO initiation was associated with reduced neurologic complications but not improved survival during the first 3 years of program implementation. These data suggest that development of a coordinated system for rapid ECMO deployment may benefit both ECPR and non-ECPR patients, but further efforts are required to improve survival.

Extracorporeal cardiopulmonary resuscitation for post-operative cardiac arrest: indications, techniques, controversies, and early results--what is known (and unknown)

Extracorporeal cardiopulmonary resuscitation may be defined as the use of extracorporeal membrane oxygenation for the support of patients who do not respond to conventional cardiopulmonary resuscitation. Data from national and international paediatric databases indicate that the use of extracorporeal cardiopulmonary resuscitation is increasing. Guidelines from the American Heart Association suggest that any patient with refractory cardiopulmonary resuscitation and potentially reversible causes of cardiac arrest is a candidate for extracorporeal cardiopulmonary resuscitation. One possible framework for selection of patients for extracorporeal cardiopulmonary resuscitation includes dividing patients on the basis of favourable or unfavourable characteristics. Favourable characteristics include cardiac disease, witnessed event in the intensive care unit, ability to deliver effective cardiopulmonary resuscitation, active patient monitoring present, favourable arterial blood gases, and early institution of extracorporeal membrane oxygenation. Unfavourable characteristics potentially include non-cardiac disease, an unwitnessed cardiac arrest, ineffective cardiopulmonary resuscitation, and severely acidotic arterial blood gases. Considering the significant resources and cost involved in the use of extracorporeal cardiopulmonary resuscitation, its use needs to be critically examined to improve outcomes, assess neurological recovery and quality of life, and help identify populations and other factors that may help guide in the selection of patients for successful extracorporeal cardiopulmonary resuscitation.

Perioperative mechanical circulatory support in children with critical heart disease

OPINION STATEMENT

The treatment of cardiovascular failure in the perioperative period with the use of mechanical circulatory support is a well-recognized, well-developed, and commonly utilized treatment modality. Regardless of the exact circumstances of initiation, the use of a support device is a "bridge." Where there has been an acute myocardial insult, short-term assist devices can serve as a "bridge to immediate survival," a "bridge to recovery," or even a "bridge to the next decision." Mechanical circulatory support can serve as a treatment of cardiovascular decompensation caused by myocarditis, acute myocardial insult, low cardiac output following surgery, and congenital heart disease. The utilization of such support carries significant risks such as bleeding, infection, and thrombosis. However, these can be minimized in order to allow for the safe and effective deployment of this therapeutic strategy. One specific therapeutic domain in which these devices provide immediate impact is during cardiac arrest. Although outcomes of cardiac arrest remain poor, use of a mechanical device as an intervention has allowed salvage of otherwise certain mortality. However, it is important to note that the utility of support was most pronounced in patients that were not on either extreme of the survival prediction curve. This can be best summarized by the concept of "not too early, not too late." Therefore, it is the responsibility of the entire care team to find the appropriate patient population in which to "pull the trigger" on mechanical support as a therapy. This decision point is supported by a monitoring strategy that can be utilized to predict deterioration and intervene adequately. Most importantly, an effective monitoring strategy allows the practitioner to judge the effectiveness of treatment and support strategies and make adjustments in a timely manner, potentially with mechanical support in the perioperative period.

Post-cardiotomy extracorporeal cardiopulmonary resuscitation in neonates with complex single ventricle: analysis of outcomes

OBJECTIVE

Extracorporeal cardiopulmonary resuscitation (ECPR) in children with cardiac arrest refractory to conventional cardiopulmonary resuscitation (CPR) has been reported with encouraging results. We sought to review outcomes of neonates with functional single ventricle (FSV) receiving post-cardiotomy ECPR.

METHODS

Forty-eight patients who required post-cardiotomy extracorporeal membrane oxygenation (ECMO) since the introduction of our ECPR protocol (January 2007-December 2009) were identified. Twenty-seven were neonates. Review of records and survival analysis were conducted.

RESULTS

Of 27 neonates receiving post-cardiotomy ECMO 20 had FSV. Fourteen had ECPR. Ten underwent Norwood operation (NO) for hypoplastic left heart syndrome (HLHS). Four had FSV other than HLHS. Three underwent Damus-Kay-Stansel or modified NO with systemic-to-pulmonary shunt (SPS) and one SPS with anomalous pulmonary venous connection repair. Mean age and weight were 7.8 ± 2.9 days and 3.44 ± 1.78 kg, respectively. ECMO median duration was 6 days (interquartile range (IQR) 3-14). Survival to ECMO discontinuation was 79% (11 of 14 patients) and at hospital discharge was 57% (8 of 14 patients). The most common cause of death was multi-organ failure (four of six deaths). At last follow-up (median: 11 months (1-34)) 43% of patients were alive. CPR mean duration for patients with favorable versus unfavorable outcome was 38.6 ± 6.3 versus 42.1 ± 7.7 min (p = 0.12). Previously reported determinants for poorer prognosis in conventional non-rescue ECMO (such as pre-ECMO pH<7.2, renal, neurological or pulmonary hemorrhage complications, and pre- and post-vasoactive inotropic score) did not influence outcome between survivors and non-survivors (p>0.05).

CONCLUSIONS

ECMO support in neonates with FSV requiring ECPR can result in favorable outcome in more than half of patients at hospital discharge. Aggressive strategy toward timely application of ECPR is justified. Expeditious ECPR deployment after proper patients' selection, refinement of CPR quality and use of adjunctive neuroprotective interventions, such as induced hypothermia, might further improve outcomes.

Mechanical support in childhood heart failure

Despite optimization of standard medical therapy, some patients with chronic heart failure will deteriorate to the point that they require hospitalization for intravenous therapies and inpatient monitoring. Once the condition is recognized, the therapeutic goals are to reverse hemodynamic derangements, correct metabolic abnormalities, and provide symptomatic relief. Achievement of these goals requires individualized care and a familiarity with the risks and benefits of particular therapies.

Extracorporeal life support systems: alternative vs. conventional circuits

Emerging technologies and practices for pediatric and neonatal extracorporeal life support (ECLS) are promising. This experiment sought to compare the Medtronic 0800 silicon rubber membrane oxygenator to the Quadrox-iD Pediatric oxygenator in the conventional roller pump circuit, as well as comparing the conventional circuit to an alternative circuit. Three circuits were set up in the experiment. Two conventional roller pump circuits were used to compare the two oxygenators and an alternative circuit consisting of the Quadrox-iD Pediatric oxygenator and Maquet Rotaflow centrifugal pump system was used to identify differences between circuits. All three circuits were primed with Lactated Ringers' solution and human blood, with an hematocrit of 40%. Testing occurred at flow rates of 250, 500, and 750 ml/ min at 37°C for mean arterial line pressures of 60, 80, and 100 mmHg. The results of the experiment showed lower pressure drops and greater retention of total hemodynamic energy (THE) across the Quadrox-iD Pediatric oxygenator compared to the Medtronic 0800 oxygenator. Furthermore, the centrifugal pump used in the alternative circuit showed no back flow at flow rates as low as 250 ml/min while, on the other hand, rpm levels were kept below 2200 for flow rates as high as 750 ml/min. Findings support the usage of the Quadrox-iD Pediatric oxygenator in a circuit utilizing the Maquet Rotaflow centrifugal pump system due to lower pressure drops and greater percentage of THE retained across the circuit. Additional advantages of the alternative circuit include rapid set-up time, easy transport, lower priming volumes, and no gravity-dependent venous drainage system so that it can be situated in close proximity to and at the level of the patient.

Extra-corporeal life support following cardiac surgery in children: analysis of risk factors and survival in a single institution

OBJECTIVE

Application of extra-corporeal life support (ECLS) following pediatric cardiac surgery varies between different institutions based on manpower availability and philosophy towards ECLS utilization. We examined a large single institution experience with postoperative ECLS in children aiming to identify outcome predictors.

METHODS

Hospital records of all children who required postoperative ECLS at our institution were reviewed. Patients' demographics, cardiac anatomy, surgical and ECLS support details were entered into a multivariable regression analysis to determine factors associated with survival.

RESULTS

Between 1990 and 2007, 180 consecutive children, median age 109 days (range: 1 day-16.9 years), required postoperative ECLS. Sixty-nine children (38%) had undergone palliative treatment for single ventricle pathology. ECLS support was required for failure to separate from cardiopulmonary bypass (n=83) or for postoperative low cardiac output state (n=97). Forty-eight patients (27%) received rescue extra-corporeal membrane oxygenation (ECMO) support during active chest compression for refractory cardiac arrest. Under ECLS support, 37 patients required surgical revision and 20 received orthotopic heart transplantation. One hundred and nine patients (61%) survived >24h following ECLS discontinuation and 68 (38%) were discharged alive. Hospital survivors required shorter ECLS support duration compared to non-survivors (median 3 vs 5 days, respectively, p=0.05) however survival occurred after up to 16 days of ECLS support. ECLS indication (OR: 0.85 for failure to separate from bypass vs postoperative low cardiac output 95% CI (0.47-1.56), p=0.62) and rescue ECMO (OR: 0.63 for rescue ECMO vs not 95%CI (0.32-1.24), p=0.18) were not associated with risk of mortality. In a multivariable logistic regression model, neurological complications (p=0.0007), prolonged ECLS duration (p=0.003), repeat ECLS requirement (p=0.02), renal dysfunction (p=0.04) and not performing heart transplantation (p=0.04) were significant factors for hospital death.

CONCLUSION

ECLS plays a valuable role in children with low cardiac output state following cardiac surgery. More than one third of those patients, including young neonates, older children, patients with single ventricle, or those requiring rescue ECMO can be salvaged. Although prognosis worsens with prolonged ECLS duration, survival can be noted up to 16 days of support. Heart transplantation is often an important ECLS exit strategy and should be considered early in selected children. Patients' survival could improve if renal and neurological complications are avoided.

Post-cardiotomy circulatory support with the Terumo Baby-Rx oxygenator in a newborn

Some patients with severe post-cardiotomy ventricular dysfunction are unable to be separated from cardiopulmonary bypass (CPB). In this setting, extracorporeal circulatory support (ECS) should be instituted to obtain eventual myocardial recovery. We present a newborn in whom an ECS was established with the oxygenator used for the surgical correction.

Survival outcomes after rescue extracorporeal cardiopulmonary resuscitation in pediatric patients with refractory cardiac arrest

OBJECTIVES

We report our experience with extracorporeal cardiopulmonary resuscitation with extracorporeal membrane oxygenation in children having cardiac arrest refractory to conventional cardiopulmonary resuscitation and explore predictors for favorable outcome (survival with grossly intact neurologic status).

METHODS

We reviewed all patients who required extracorporeal cardiopulmonary resuscitation from 2000 to 2005. Multivariable regression analysis determined factors associated with favorable outcome and time-related survival.

RESULTS

Eighty children, median age 150 days (range: 1 day-17.6 years), required venoarterial extracorporeal cardiopulmonary resuscitation. There were several categories of disease among the patients: postcardiotomy (n = 39), unoperated congenital heart disease (n = 17), cardiomyopathy (n = 12), respiratory failure (n = 9), or myocarditis (n = 3). Cannulation sites were neck (n = 45) or chest (n = 36). Median duration of extracorporeal membrane oxygenation was 4 days (range: 1-22). Extracorporeal membrane oxygenation was successfully discontinued in 42 (54%) patients: wean (n = 35), heart transplantation (n = 7). Survival till hospital discharge was 27 (34%) patients. Most common cause of death was ischemic brain injury (n = 17). Twenty-four (30%) patients had a favorable outcome. Median duration of cardiopulmonary resuscitation for patients with favorable versus unfavorable outcome was 46 minutes (range: 14-95; interquartile range: 29-55) versus 41 minutes (range: 19-110; interquartile range: 30-55), P = .916. According to the logistic regression model, none of the following factors was a significant predictor of favorable outcome: age, weight, sex, etiology (cardiac vs noncardiac), duration of cardiopulmonary resuscitation, cannulation site, timing, or location of extracorporeal membrane oxygenation institution.

CONCLUSIONS

Acceptable survival and neurologic outcomes (30%) can be achieved with extracorporeal cardiopulmonary resuscitation in children after prolonged cardiac arrest (up to 95 minutes) refractory to conventional resuscitation measures. Heart transplantation is often needed for successful extracorporeal cardiopulmonary resuscitation exit strategy. Lack of predictors of poor outcome support aggressive attempts to initiate extracorporeal cardiopulmonary resuscitation in all patients, followed by subsequent assessment of organ salvage.

Clinical implication of blood levels of B-type natriuretic peptide in pediatric patients on mechanical circulatory support

BACKGROUND

B-type natriuretic peptide (BNP) is a marker of heart failure. In adult patients with heart failure, decreased BNP levels after implantation of ventricular assist devices may be indicative of recovery. However, BNP levels among pediatric patients receiving mechanical support are largely unknown.

METHODS

Fifteen pediatric patients with cardiogenic shock who were supported by extracorporeal membrane oxygenation (ECMO) were evaluated. The BNP levels were determined before ECMO initiation, during ECMO support, and after ECMO removal.

RESULTS

All patients had elevated BNP levels before initiation of ECMO (median, 1,430 pg/mL; range, 361 to 5,000 pg/mL). Among the 15 patients, 1 received heart transplantation. Extracorporeal membrane oxygenation was withdrawn in 2 patients, and the other 12 patients were weaned from ECMO. Four patients died after initially successful weaning from ECMO. The BNP levels of the nonsurvivors (median, 3,685 pg/mL; range, 2,494 to 5,000 pg/mL) were higher than those of the survivors (median, 1,127pg/mL; range, 108 to 3,030 pg/mL) on the next few days after ECMO removal (p = 0.016). The BNP levels on the fourth day after removal of ECMO among the survivors (median, 498 pg/mL; range, 108 to 890 pg/mL) were lower than those among the nonsurvivors (median, 3,900 pg/mL; range, 3,230 to 5,000 pg/mL; p = 0.017).

CONCLUSIONS

Among pediatric patients supported with ECMO, the survivors had lower BNP levels than those who did not survive. We suggest that serial blood BNP levels can be potential markers for monitoring pediatric patients on mechanical circulatory support, and the concept merits further study.

Cardiac extracorporeal life support: state of the art in 2007

Mechanical circulatory support is an invaluable tool in the care of children with severe refractory cardiac and or pulmonary failure. Two forms of mechanical circulatory support are currently available to neonates, infants, and smaller children, namely extracorporeal membrane oxygenation and use of a ventricular assist device, with each technique having unique advantages and disadvantages. The intra-aortic balloon pump is a third form of mechanical support that has been successfully used in larger children, adolescents, and adults, but has limited applicability in smaller children. In this review, we discuss the current experiences with extracorporeal membrane oxygenation and ventricular assist devices in children with cardiac disease.A variety of forms of mechanical circulatory support are available for children with cardiopulmonary dysfunction refractory to conventional management. These devices require extensive resources, both human and economic. Extracorporeal membrane oxygenation can be effectively used in a variety of settings to provide support to critically-ill patients with cardiac disease. Careful selection of patients and timing of intervention remains challenging. Special consideration should be given to children with cardiac disease with regard to anatomy, physiology, cannulation, and circuit management. Even though exciting progress is being made in the development of ventricular assist devices for long-term mechanical support in children, extracorporeal membrane oxygenation remains the mainstay of mechanical circulatory support in children with complex anatomy, particularly those needing rapid resuscitation and those with a functionally univentricular circulation.As the familiarity and experience with extracorporeal membrane oxygenation has grown, new indications have evolved, including emergent resuscitation. This utilization has been termed extracorporeal cardiopulmonary resuscitation. The literature supporting emergent cardiopulmonary support is mounting. Reasonable survival rates have been achieved after initiation of support during active compressions of the chest following in-hospital cardiac arrest. Due to the limitations of conventional circuits for extracorporeal membrane oxygenation, some centres have developed novel systems for rapid cardiopulmonary support. Many centres previously considered a functionally univentricular circulation to be a contraindication to extracorporeal membrane oxygenation, but improved results have been achieved recently with this complex subset of patients. The registry of the Extracorporeal Life Support Organization recently reported the outcome of extracorporeal life support used in neonates for cardiac indications from 1996 to 2000. Of the 740 neonates who were placed on extracorporeal life support for cardiac indications, 118 had hypoplastic left heart syndrome. There was no significant difference in survival between these patients and those with other defects. It is now common to use extracorporeal membrane oxygenation to support patients with a functionally univentricular circulation, and reasonable survival rates are to be expected. Although extracorporeal membrane oxygenation has become a standard of care for many paediatric centres, its use is limited to those patients who require only short-term cardiopulmonary support. Mechanical ventricular assist devices have become standard therapy for adults with cardiac failure refractory to maximal medical management. Several devices are readily available in the United States of America for adults, but there are fewer options available to children. Over the last few years, substantial progress has been made in paediatric mechanical support. Ventricular assist devices are being used with increasing frequency in children with cardiac failure refractory to medical therapy for primary treatment as a long-term bridge to recovery or transplantation. The paracorporeal, pneumatic, pulsatile "Berlin Heart" ventricular assist device is being used with increasing frequency in Europe and North America to provide univentricular and biventricular support. With this device, a patient can be maintained on mechanical circulatory support while extubated, being mobilized, and feeding by mouth. Mechanical circulatory support should be anticipated, and every attempt must be made to initiate support "urgently" rather than "emergently", before the presence of dysfunction of end organs or circulatory collapse. In an emergency, these patients can be resuscitated with extracorporeal membrane oxygenation and subsequently transitioned to a long-term ventricular assist device after a period of stability.

Factors influencing the outcome of paediatric cardiac surgical patients during extracorporeal circulatory support

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (ECMO) is a common modality of circulatory assist device used in children. We assessed the outcome of children who had ECMO following repair of congenital cardiac defects (CCD) and identified the risk factors associated with hospital mortality.

METHODS

From April 1990 to December 2003, 53 patients required ECMO following surgical correction of CCD. Retrospectively collected data was analyzed with univariate and multivariate logistic regression analysis.

RESULTS

Median age and weight of the patients were 150 days and 5.4 kgs respectively. The indications for ECMO were low cardiac output in 16, failure to wean cardiopulmonary bypass in 13, cardiac arrest in 10 and cardio-respiratory failure in 14 patients. The mean duration of ECMO was 143 hours. Weaning off from ECMO was successful in 66% and of these 83% were survival to hospital-discharge. 37.7% of patients were alive for the mean follow-up period of 75 months. On univariate analysis, arrhythmias, ECMO duration >168 hours, bleeding complications, renal replacement therapy on ECMO, arrhythmias and cardiac arrest after ECMO were associated with hospital mortality.On multivariate analysis, abnormal neurology, bleeding complications and arrhythmias after ECMO were associated with hospital mortality. Extra and intra-thoracic cannulations were used in 79% and 21% of patients respectively and extra-thoracic cannulation had significantly less bleeding complications (p = 0.031).

CONCLUSION

ECMO provides an effective circulatory support following surgical repair of CCD in children. Extra-thoracic cannulation is associated with less bleeding complications. Abnormal neurology, bleeding complications on ECMO and arrhythmias after ECMO are poor prognostic indicators for hospital survival.

Aristotle Score Predicts Outcome in Patients Requiring Extracorporeal Circulatory Support Following Repair of Congenital Heart Disease

Extracorporeal membrane oxygenation (ECMO) has become the standard technique of mechanical support for the failing circulation following repair of congenital heart lesions. The objective of this study was to identify predictors of survival in patients requiring postcardiotomy ECMO. The Aristotle score, a method developed to evaluate quality of care based on complexity, was investigated as a potential predictor of outcome. Between 2003 and 2005, 37 patients required ECMO following corrective surgery for congenital heart disease. Records were reviewed retrospectively with emphasis on factors affecting survival to discharge. The comprehensive Aristotle complexity score was calculated for each patient. Overall, 28 patients (76%) survived to decannulation and 17 patients (46%) survived to discharge. There were 24 (65%) neonates and 10 patients (27%) with single ventricle physiology, with a hospital survival of 42% (10 of 24) and 50% (5 of 10), respectively. Univariate factors associated with survival included Aristotle score, duration of support, reexploration, multiple organ failure, and number of complications. Age, weight, and single-ventricle physiology were not significant. In a logistic regression model, an Aristotle score < 14 was identified as a predictor of survival (OR 0.12, CI 0.02-0.87). The Aristotle score is predictive of outcome in patients requiring postcardiotomy ECMO and may serve as a uniform criterion when comparing and evaluating quality of care and performance in this complex patient population.

Rapid Cardiopulmonary Support in Children With Heart Disease: A Nine-Year Experience

BACKGROUND

We developed a novel mechanical rapid cardiopulmonary support system (CPS) in 1996 to eliminate what we believed were shortcomings of conventional extracorporeal membrane oxygenation (ECMO) circuits when used in patients with congenital heart disease. We reviewed the use of this system over a nine year period to determine if we had been successful in improving results compared with ECMO and if outcomes have changed over this time.

METHODS

All children supported with CPS (110 procedures) were reviewed. Noncardiac CPS cases (7) were excluded. The study population was divided into two time periods (1995 to 2000 and 2001 to 2004), which correlate with significant differences in intraoperative, postoperative, and CPS management. Patients were further analyzed by age (< or = 30 days or > 30 days), repair complexity (risk adjusted classification for congenital heart surgery [RACHS]-1 category 6 or categories 1 to 5), and length of support.

RESULTS

Overall thirty day survival of cardiac CPS patients was 55% (57 of 103). Overall survival increased from 45% (23 of 51) during the first period to 65% (34 of 52) during the second period [p < or = 0.005]. Survival rates in neonates improved from 41% (11 of 27) to 56% (15 of 27) and RACHS-1 category 6 survival improved from 38% (5 of 13) to 69% (9 of 13), but neither change reached statistical significance. Intracranial hemorrhage occurred in 6.4% of all CPS patients.

CONCLUSIONS

Cardiopulmonary support is an effective alternative to ECMO for pediatric cardiac support. Further, our experience suggests that patient survival may be improved by CPS compared with reported results for ECMO in cardiac patients.

Matching the Mechanical Circulatory Support Device to the Child With Heart Failure

A number of mechanical circulatory support devices are currently available for the treatment of children with heart failure refractory to medical therapy. Patient size, the acute versus chronic nature of the heart failure that is present, and the underlying anatomy and physiology define the clinical setting in any given case. Determining which device most effectively meets the specific needs of the clinical setting requires an understanding of the characteristics of each of the available devices. This report describes a graphic representation of the clinical setting in which pediatric heart failure occurs to provide a decision-making framework for the selection of the most appropriate mechanical circulatory support device.

Improved survival after cardiac arrest using emergent autopriming percutaneous cardiopulmonary support

BACKGROUND

Emergent percutaneous cardiopulmonary support (PCPS) has the potential to rescue patients in cardiac arrest who might otherwise die. We retrospectively reviewed the results of PCPS using preassembled, heparin-coated, and autopriming devices in patients in cardiac arrest.

METHODS

From November 2003 to July 2005, 22 patients in cardiac arrest underwent PCPS using the Capiox emergent bypass system (Terumo, Tokyo, Japan). The mean +/- SD age was 63 +/- 14 (range, 31 to 85) years. In six patients, the underlying disease causing cardiac arrest was not diagnosed before PCPS. The procedure involved 14 to 21 Fr percutaneous femoral arterial cannulae and 17 to 28 Fr percutaneous femoral long venous cannulae. The mean duration of cardiopulmonary resuscitation before PCPS was 48.5 +/- 29.0 (range, 15 to 143) minutes. An intraaortic balloon pump was used concomitantly in six patients.

RESULTS

Fourteen patients received additional surgical or interventional procedures during PCPS. Thirteen (59%) patients could be weaned off PCPS after 52.3 +/- 47.8 (range, 4 to 141) hours of support. Twelve complications occurred in 11 patients, including eight related to PCPS: low perfusion flow (two), gastrointestinal bleeding (two), surgical wound bleeding (one), femoral arterial catheter dislodgement (one), hemolysis with acute renal failure (one), and mitral valve thrombus (one). Nine patients (41%) were discharged from hospital without neurologic complications. The incidence of complications differed in comparisons between patients who survived and did not survive.

CONCLUSIONS

The use of preassembled, heparin-coated and autoprimed devices enabled us to rescue in-hospital cardiac arrest patients who might have died without this procedure.

Extracorporeal membrane oxygenation after stage I reconstruction for hypoplastic left heart syndrome

OBJECTIVE

Although extracorporeal membrane oxygenation (ECMO) is an acceptable strategy for children with refractory cardiac dysfunction after cardiac surgery, its role after stage I reconstruction for hypoplastic left heart syndrome and its variants is controversial. Our objective is to describe the outcome of "nonelective" ECMO after stage I reconstruction.

DESIGN

Retrospective case series.

SETTING

Pediatric cardiac intensive care unit.

PATIENTS

Infants placed on ECMO after stage I reconstruction from January 1998 to May 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 382 infants who underwent stage I reconstruction during the study period, 36 (9.4%) required ECMO in the postoperative period. There were 22 infants with hypoplastic left heart syndrome. Indications for ECMO included inability to separate from cardiopulmonary bypass in 14 and cardiac arrest in 22. Fourteen infants (38.8%) survived to hospital discharge. Nonsurvivors had longer cardiopulmonary bypass time (150.1 +/- 70.0 mins vs. 103.9 +/- 30.0 mins, p =. 01). 9/14 infants (64%) supported with ECMO> than 24 hrs after stage I reconstruction survived while only 5/22 infants (22%) requiring ECMO< 24 hrs of stage I reconstruction survived (p =. 02). Of note, all five infants diagnosed with an acute shunt thrombosis were early survivors. Mean duration of ECMO was 50.1 +/- 12.5 hrs for survivors and 125.2 +/- 25.0 for nonsurvivors (p =. 01). 7/14 early survivors are alive at a median follow-up of 20 months (2-78 months).

CONCLUSIONS

In our experience, ECMO after stage I reconstruction can be life saving in about a third of infants with otherwise fatal conditions. It is particularly useful in potentially reversible conditions such as acute shunt thrombosis and transient depression of ventricular function.

Clinical outcomes in pediatric patients implanted with Thoratec ventricular assist device

Most mechanical circulatory support devices are designed for adult patients; however, some can be successfully applied to pediatric patients. The rates of complications and patient survival to transplant or native heart recovery after implantation of the Thoratec ventricular assist device (VAD) (Thoratec Corp, Pleasanton, CA) in children and adolescents were determined from the company's voluntary registry. As of January 2005, 209 patients (mean age 14.5 years; range 5 to 18 years) have been supported with the Thoratec VAD. Mean patient weight was 57 kg (range, 17 to 118 kg), and patients had a mean body surface area of 1.6 m2 (range, 0.73 to 2.3 m2). The major etiologies necessitating VAD support included cardiomyopathy (55.0%), acute myocarditis (25.4%), and end-stage congenital heart disease (5.8%). Mean duration of VAD support was 44 days (range, 0 to 434 days). Patient survival to transplantation or native heart recovery was 68.4%. Patients with cardiomyopathy and acute myocarditis had 74.1% and 86.0% survival, respectively, with only 27.3% survival in patients having congenital heart disease. The overall survival rate in smaller children (body surface area, <1.3 m2) was similar at 51.7%, although the incidence of congenital heart disease was higher.

Mechanical cardiac support in the young. Short-term support: ECMO

Although based on technology developed several decades ago, extracorporeal membrane oxygenation (ECMO) retains great clinical relevance in the management of advanced pediatric cardiorespiratory disease. Largely because of its widespread use in pediatric patients with respiratory failure, familiarity with this technology has established ECMO as the most commonly used form of mechanical circulatory support in children. Clinical applications and technical aspects of ECMO support continue to evolve, ensuring the ongoing importance of this modality for pediatric circulatory support.

New developments in pediatric cardiac anesthesia

As the practice of pediatric cardiac anesthesia continues to grow, anesthesiologists now routinely care for patients ranging in size from less than 2 kg to more than 100 kg. New clinical and laboratory research has enhanced our understanding of the effects of anesthetic drugs on the pediatric myocardium, and improvements in survival statistics for even the smallest and sickest infants have shifted the emphasis to evaluation of quality of life and neurological outcome in pediatric cardiac patients. The use of circulatory support in infants and children, both for rapid resuscitation and for more chronic indications such as bridge to transplantation, also continues to evolve, with the recent introduction of pulsatile and axial pumps for pediatric use. This article reviews anesthetic agents, bleeding and coagulation, neurological monitoring, and mechanical circulatory support in the treatment of infants and children.

Pediatric cardiopulmonary bypass devices: trends in device use for cardiopulmonary bypass and postcardiotomy support

Cardiopulmonary bypass (CPB) devices and techniques have continuously evolved. We have conducted surveys that chronicle the changes in CPB devices and techniques used at North American pediatric cardiac surgery centers since 1989. The aim of this article is to describe trends in cardiopulmonary bypass device use during cardiac surgery and changes in the devices used for extracorporeal life support (ECLS) following cardiac surgery for pediatric patients. The diffusion of innovation in pediatric cardiovascular surgery has not been solely driven by the availability of scientific evidence to support change but rather it has often been related to other factors that influence clinicians willingness to change including; tradition, ease of use, and cost related pressures. The current CPB systems used for cardiac surgery are more homogenous than in previous years. Most centers use a heparin coated or modified surface system comprised of a "hard shell" open venous reservoir, a roller pump, a hollow fiber membrane oxygenator, and arterial line filter. ECLS systems comprised of hollow fiber oxygenators and centrifugal pumps for are gradually replacing the classical ECLS circuit, servo regulated roller pumps and silicone rubber membranes. Nearly 40% of centers use these alternate components in their ECLS systems. Costs, utility, safety and measurable benefit to the patient should guide decisions related to device selection.

Mechanical support of the functionally single ventricle

Children with a functionally single ventricle constitute just over 1% of congenital cardiac defects.1A majority of children with the functionally univentricular circulation undergo a three-staged reconstruction to achieve completion of the Fontan circulation. The first stage is usually performed in the neonatal period, and is either banding of the pulmonary trunk, an aorto-pulmonary shunt alone, or the shunt included as part of the first stage of reconstruction. In recent years, a conduit placed from the right ventricle to the pulmonary arteries is being used as an alternate source of flow of blood to the lungs. The second stage is the bidirectional cavopulmonary anastomosis, the two surgical variations being the so-called “hemifontan”, and “bidirectional Glenn” procedures, while the third stage is the completion of the Fontan circulation, the two surgical variations being either construction of a lateral tunnel, or placement of an extra-cardiac conduit, each being possible with or without a fenestration. In many centres, patients with the functionally univentricular circulation make up one-fifth of the total surgical volume. The syndrome of low cardiac output is quite common in this population through all three stages of reconstruction, and some of these patients will eventually require cardiac transplantation. While conventional therapy, with inotropic support and afterload reduction, remains the mainstay of therapy for the failing heart in children, mechanical support is being increasingly used.3Most of this experience is limited to extracorporeal membrane oxygenation.2–5In this review, we discuss the current experiences with extracorporeal membrane oxygenation in patients with a functionally univentricular circulation, and describes some of their unique features. We also focus on the pulsatile ventricular assist devices capable of providing support over the longer term, and other new devices that may have a role in the future in these patients.6

Pediatric Mechanical Circulatory Support

Extracorporeal membrane oxygenation (ECMO) is based on technology that has been used clinically for decades. Largely because of its widespread use in pediatric patients with respiratory failure, familiarity with this technology has established ECMO as the most commonly used form of circulatory support for children. However, clinical applications and technical aspects of ECMO support continue to evolve, ensuring the ongoing importance of this modality for pediatric circulatory support. Although traditionally lagging behind development for adult applications, the use of ventricular assist devices (VADs) is expanding in pediatrics. Of particular interest, a number of new VADs designed specifically for children are becoming available, while early development of some innovative devices for pediatric circulatory support is currently underway.

Patterns of Lactate Values after Congenital Heart Surgery and Timing of Cardiopulmonary Support

BACKGROUND

We sought to determine if postoperative serial lactate determinations follow predictable patterns that could be useful in directing management, especially the initiation of postoperative mechanical cardiopulmonary support (CPS).

METHODS

Eight patients undergoing CPS in a 2-year period and 147 patients not requiring postoperative CPS in 6 months of that period were stratified into 6 categories based on short-term risk for mortality (1 being the lowest risk). Lactate values for the first 48 hours postoperatively were retrospectively analyzed.

RESULTS

Survivors not requiring CPS in category 6 (n = 16) followed a distinct pattern different from those of categories 1 through 4 (n = 128). Review of postoperative CPS survivors (n = 4) indicated that CPS was initiated electively without cardiac arrest in all 4, and lactate values showed a downward trend within 12 hours of initiation in all cases (mean lactate, 10.12 +/- 1.88 mmol/L; range, 1.4 to 16 mmol/L; mean initiation time, 16.5 hours postoperatively). Three fourths of the CPS nonsurvivors suffered cardiac arrest before CPS and showed rising lactate values despite support (mean lactate, 11.95 +/- 1.37 mmol/L; range, 1.6 to 18.6 mmol/L; mean initiation time, 21.25 hours postoperatively). Indications for initiation of CPS in patients with elevated lactate values were reviewed. Two thirds of patients who died without CPS had preterminal cardiac arrest.

CONCLUSIONS

We have defined the normal pattern of postoperative lactate values in our institution. These data suggest that an abnormal lactate pattern may be useful in determining the timing of CPS initiation in hemodynamically stable patients with high or rising lactate values, before cardiac arrest or end organ damage.

Decision making for mechanical cardiac assist in pediatric cardiac surgery

The practice of pediatric cardiac surgery has evolved to the point where the majority of patients operated on represent the most complex end of the spectrum of congenital heart disease. Given this, the potential role for mechanical cardiac assist will continue to expand. Although extracorporeal membrane oxygenation remains the mainstay of mechanical circulatory assist, the increased use of centrifugal ventricular assist devices is changing the approach to the treatment of acute cardiac failure. A range of newly developed implantable and paracorporeal devices is beginning to make its way into the clinical practice of pediatric cardiac surgery. This article addresses the different types of support available for mechanical cardiac assist and the clinical considerations in selecting the appropriate device.

Plasticizer di(2-ethylhexyl)phthalate (DEHP) release in wet-primed extracorporeal membrane oxygenation (ECMO) circuits

A wet-primed ready-to-use extracorporeal membrane oxygenation (ECMO) circuit is used in some centres for rapid deployment of ECMO during cardiopulmonary resuscitation. Yet, the potential release of plasticizer di(2-ethylhexyl)phthalate (DEHP) from the polyvinyl chloride tubing in the circuit during storage is a concern. In this study, a high performance liquid chromatography method was used to determine the concentration of DEHP in the priming solution (Plasmalyte) from an ECMO circuit stored for up to 14 days at 8 degrees C. No accumulation of DEHP in the circulating fluid was detected. The results provide important information for centres where ECMO circuits are kept wet-primed prior to clinical use.

Extracorporeal membrane oxygenation for cardiac disease: no longer a mistaken diagnosis

Extracorporeal membrane oxygenation (ECMO) has become a valuable adjunct in caring for infants and children with heart disease. Since the initial reports of ECMO support for cardiac failure in children, the number of centers providing cardiac support and the number of cases of cardiac ECMO have steadily increased. The International Registry for Extracorporeal Life Support Organization has reported survival statistics for cardiac cases in neonates, children, and adults ranging from 33% to 43%. These numbers are similar to the survival from recent reports by Morris (39%) and Chaturvedi (49%). Survival is influenced by ability to be weaned from bypass in the operating room and by residual structural disease and multi-organ system failure but not by cardiac arrest and single ventricle physiology. To improve results in the future, we need to focus on better predicting the need for support and avoiding multi-organ system failure before initiating ECMO. Rapid deployment of ECMO may further improve results for patients who deteriorate suddenly in the intensive care unit.

Interventional catheterization performed in the early postoperative period after congenital heart surgery in children

OBJECTIVES

The purpose of this study was to examine the safety and efficacy of interventional catheterization performed early after congenital heart surgery.

BACKGROUND

Transcatheter interventions performed in the early postoperative period are viewed as high risk. To date, there have been limited published data regarding these procedures.

METHODS

All catheterizations performed within six weeks after congenital heart surgery between August 1995 and January 2001 were retrospectively reviewed. A cardiac anesthesiologist, cardiac intensivist, cardiac surgeon, and operating room team were available for all cases. Interventional procedures were performed based on clinical indications, regardless of the time elapsed from surgery.

RESULTS

Sixty-two patients, median age four months (2 days to 11 years), weight 4.7 kg (2.3 to 45 kg), underwent 66 catheterizations on median postoperative day 9 (0 to 42 days). Thirty-five cases involved 50 interventional procedures. Nine patients required extracorporeal cardiopulmonary support. Success rates by procedure were: angioplasty, 100%; stent implantation, 87%; vascular/septal occlusion, 100%; and palliative pulmonary valvotomy, 75%. Complications included stent migration (one patient), cerebral vascular injury (one patient), and left pulmonary artery stenosis (one patient). Thirty procedures involved angioplasty or stent implantation, including 26 involving a recently created suture line. Suture disruption or trans-mural vascular tears were not observed. There was no procedural mortality. Thirty-day survival for patients undergoing intervention was 83%.

CONCLUSIONS

Transcatheter interventions can be successfully performed in the early postoperative period. These procedures can have a positive impact on patient outcome; however, they should be performed only by a pediatric interventional cardiologist supported by a multi-disciplinary team.

Postoperative management in patients with complex congenital heart disease

Life-threatening problems occur in the neonate and infant after cardiac surgery because of the interplay of diminished cardiac output (CO), increased metabolic demand, inflammatory responses to cardiopulmonary bypass, and maladaptive responses to stress. Therefore, the postoperative management of patients with complex congenital heart defects is directed at optimization of oxygen delivery to maintain end-organ function and promote wound healing. Traditionally, assessment of circulation in the postoperative congenital heart patient has depended on indirect assessment of CO using parameters such as blood pressure, pulses, capillary refill, and urine output. Because of the limitations of indirect and observer-dependent assessment of CO, we rely on objective measures of tissue oxygen levels for the complex postoperative patient. We have found that continuous monitoring of the mixed venous saturation (SvO2) allows for identification of acute changes in systemic oxygen delivery and frequently precedes other indicators of decreased CO. The postoperative patient can be expected to have a period of decreasing CO, and the need for intervention should be anticipated because critical low output syndrome will develop in a subset of patients. Strategies for postoperative care are developed based on the diagnosis and procedure, but optimizing SvO2 is a consistent goal. A uniform approach to airway maintenance, vascular access, and drug infusions, all universal concerns during the perioperative period, minimizes the potential for these predictable and necessary interventions to result in morbidity or mortality. Management of the postoperative single ventricle patient targets stabilization of the systemic vascular resistance through the use of vasodilators to improve systemic perfusion and simplify ventilator management. Management of any individual patient should be driven by objective analysis of available data and must include efforts to re-evaluate the treatment plan as well as to identify unanticipated problems.

Achieving resonance in a programme for congenital cardiac surgery

In 1995, Miami Children's Hospital recognized an institutional problem with its programme providing surgical treatment for congenital cardiac malformations. There was a high rate of mortality for neonatal surgery, and no patients had survived attempted first stage palliation for hypoplastic left heart syndrome. The hospital enlisted nationally recognized consultants in congenital cardiac surgery and cardiology to review the existing programme, and to make recommendations for improvement. Based on these recommendations, a new team was recruited. The recruits were a young attending surgeon, an interventional cardiologist, and a cardiac intensivist, attracted from recognized centers of excellence in Boston and Toronto.

Pediatric arteriovenous extracorporeal membrane oxygenation (ECMO) as a bridge to cardiac transplantation

BACKGROUND

Since 1990, extracorporeal membrane oxygenation (ECMO) has been used as a bridge to cardiac transplantation in 47 patients.

METHODS

A review of the ECMO database, approved by the Arkansas Children's Hospital institutional review board, forms the basis of this report. We made statistical comparison using Fisher's exact probability testing. The ECMO circuitry was a roller occlusion pump with computer-assisted perfusion system technology.

RESULTS

Thirty-two (68%) patients underwent transcatheter septostomy for cardiac decompression. Diagnosis at presentation was either congenital heart disease (CHD, n = 15) or cardiomyopathy (n = 32). Ages ranged from 1 day to 22 years old (median, 18 months old), and weight ranged from 2.9 to 100 kg (median, 10 kg). The average duration of support was 242 hours (range, 22-1078 hours). Overall long-term survival was 47%, with 16 (34%) patients successfully bridged to cardiac transplantation (of which 9 [56%] survived) and 13 (28%) successfully weaned from ECMO. Patients undergoing ECMO after cardiotomy had 31% survival. Survival was improved significantly (p < 0.02) in patients with cardiomyopathy (59%) vs those with CHD (20%). Patients with cardiomyopathy underwent 8 transplantations with 7 survivors (88%), whereas in the CHD group, there were 8 transplantations with only 2 survivors (25%), p < 0.05. Sub-analysis of the cardiomyopathy group revealed that patients with acute cardiomyopathy in association with documented viral illness had a 75% chance of being weaned from ECMO without undergoing transplantation. Complications during ECMO occurred in 45% of survivors and were more frequent in non-survivors. Infectious complications were most frequent, followed by neurologic complications, technical ECMO problems, and renal insufficiency.

CONCLUSIONS

Patients with cardiomyopathy has a better prognosis than did those with CHD when using ECMO as a bridge to transplantation or survival. Complications are significant and increase with the duration of support. Extracorporeal membrane oxygenation for salvage and subsequent transplantation in this high-risk group of patients requires critical review. Alternative support options must be developed in the pediatric population that will allow improved outcomes, comparable with outcomes achieved in the adult population.

Percutaneous cardiopulmonary bypass for cardiac emergencies

Percutaneous cardiopulmonary support systems (PCPS) are compact, battery-powered, portable heart-lung machines that can be implemented rapidly in any area of the hospital using thin-walled cannulae inserted via the femoral vessels. PCPS provides temporary circulatory support by actively aspirating blood from the patient's venous system using a centrifugal pump and hollow fiber membrane oxygenator for gas exchange. A review of clinical reports has delineated several indications for emergent applications, with the most frequent being cardiac arrest (CA) or cardiogenic shock (CS). Survival is more likely in patients with CS (40%) compared to CA (21%). Implementation of PCPS after unwitnessed CA or cardiopulmonary resuscitation > 30 min yields a patient survival rate of < 10%. The likelihood of patient survival after emergent PCPS is most often related to the patient undergoing a definitive anatomic surgical repair such as coronary artery bypass or pulmonary embolectomy. If the need for circulatory support extends beyond 6 h, conversion to conventional long-term extracorporeal membrane oxygenation or a ventricular assist device is recommended.