Is there a role for extracorporeal life support after stage I Norwood?

Postcardiotomy extracorporeal membrane oxygenation in patients with congenital heart disease; the effect of place of initiation

BACKGROUND

Postcardiotomy extracorporeal membrane oxygenation (ECMO) in pediatric patients can be affected by the place of initiation, either in the operating room (OR) or the pediatric cardiac intensive care unit (PCICU). This study aimed to characterize and compare patients who had postcardiotomy ECMO initiation in the OR or PCICU and evaluate risk factors for hospital mortality.

METHODS

This retrospective study included 103 patients who required postcardiotomy ECMO support after the repair of congenital cardiac lesions from 2010 to 2022. Patients were grouped according to the place of ECMO insertion into two groups. Group 1 (n = 69) had ECMO insertion in the OR, and Group 2 (n = 34) had ECMO insertion in the PCICU.

RESULTS

Cardiac arrest occurred significantly more often in patients with ECMO insertion in the PCICU (21 (61.76%) vs. 13 (18.84%); p < 0.001). Pre-ECMO lactate levels, pH, VIS, base deficit, and PaO2 did not differ between the groups. Re-exploration for bleeding was significantly higher in Group 1 (32 (46.38%) vs. 8 (23.53%); p = 0.03). Cannula repositioning (4 (11.76%) v. 2 (2.90%); p = 0.09) and mechanical ventilation time were nonsignificantly higher in Group 2 (19.5 (10-31) vs. 11 (5-25) days; p = 0.07). No difference in mortality was found between groups (42 (60.87%) vs. 23 (67.65%), p = 0.50). By multivariable analysis, elevated lactate on ECMO and low pH before ECMO were associated with mortality.

CONCLUSIONS

ECMO insertion in the OR has a comparable mortality rate to PCICU insertion. Pre-ECMO low pH and high lactate during ECMO could predict mortality.

Early outcomes after post-cardiotomy extracorporeal membrane oxygenation in paediatric patients: a contemporary, binational cohort study

OBJECTIVES

The aim of this study was to assess the early outcomes and risk factors of paediatric patients requiring extracorporeal membrane oxygenation after cardiac surgery (post-cardiotomy).

METHODS

Retrospective binational cohort study from the Australia and New Zealand Congenital Outcomes Registry for Surgery database. All patients younger than 18 years of age who underwent a paediatric cardiac surgical procedure from 1 January 2013 to 31 December 2021 and required post-cardiotomy extracorporeal membrane oxygenation (PC-ECMO) in the same hospital admission were included in the study.

RESULTS

Of the 12 290 patients included in the study, 376 patients required post-cardiotomy ECMO (3%). Amongst these patients, hospital mortality was 35.6% and two-thirds of patients experienced a major complication. Hypoplastic left heart syndrome was the most common diagnosis (17%). The Norwood procedure and modified Blalock-Taussig shunts had the highest incidence of requiring PC-ECMO (odds ratio of 10 and 6.8 respectively). Predictors of hospital mortality after PC-ECMO included single-ventricle physiology, intracranial haemorrhage and chylothorax.

CONCLUSIONS

In the current era, one-third of patients who required PC-ECMO after paediatric cardiac surgery in Australia and New Zealand did not survive to hospital discharge. The Norwood procedure and isolated modified Blalock-Taussig shunt had the highest incidence of requiring PC-ECMO. Patients undergoing the Norwood procedure had the highest mortality (48%). Two-thirds of patients on PC-ECMO developed a major complication.

Use of extracorporeal membrane oxygenation and cerebral oximetry in a stage 1 norwood repair for hypoplastic left heart syndrome

The role of extracorporeal membrane oxygenation (ECMO) and its indications in stage I Norwood palliation are controversial. The decision to initiate ECMO and its timing remains difficult with no definitive cut-off points or evidence-based guidelines. It varies on a case-to-case basis. We report a case where the use of ECMO was beneficial after stage I Norwood palliation with severe ventricular dysfunction. The systemic-to-pulmonary artery shunt was kept open to balance the systemic and pulmonary circulations. Cerebral oximetry can be useful as an additional monitoring modality to guide management, monitor cerebral perfusion, and help detect cerebral steal.

Impact of Intraoperative Residual Lesions and Timing of Extracorporeal Membrane Oxygenation on Outcomes Following First-Stage Palliation of Single Ventricle Heart Disease

BACKGROUND

Data regarding the influence of intraoperative residual lesions on extracorporeal membrane oxygenation (ECMO) following the Norwood procedure are limited. Moreover, the significance of postoperative ECMO timing on in-hospital outcomes remains incompletely characterized.

METHODS

This was a single-center, retrospective review of consecutive patients who underwent the Norwood operation from January 1997 to November 2017. Patients with at least minor residual lesions based on the intraoperative postcardiopulmonary bypass echocardiogram were identified. The association between residual lesions and postoperative ECMO was assessed with logistic regression, adjusting for age, weight, prematurity, various preoperative system-specific and procedural risk factors, shunt type, and era. Among patients receiving ECMO, associations between late ECMO (≥3 days post-Norwood) and in-hospital mortality or transplant, postoperative hospital length-of-stay, and cost of hospitalization were evaluated using logistic regression or generalized linear models with a gamma distribution and logarithmic link.

RESULTS

Among 500 patients, 78 (15.6%) received ECMO postoperatively. On multivariable analysis, the presence of at least minor residual lesions (odds ratio, 4.4; 95% CI, 2.1-9.3; P < .001) was associated with postoperative ECMO. In the ECMO subpopulation, there were 44 (56.4%) deaths or transplants. Late ECMO was associated with increased risk of in-hospital mortality or transplant (adjusted odds ratio, 6.2; 95% CI, 1.5-26.0), longer postoperative hospital length of stay (regression coefficient, 0.7; 95% CI, 0.3-1.1), and greater cost (regression coefficient, 0.6; 95%, CI 0.4-0.7), versus early ECMO (all P values < .05).

CONCLUSIONS

The presence of even minor intraoperative residua significantly increases the risk of ECMO following the Norwood operation. Among patients receiving ECMO postoperatively, early institution of ECMO is associated with lower mortality and resource utilization.

Outcomes Following Norwood Procedures: Analysis of a "Small Volume" Program

BACKGROUND

Institutional survival following Norwood procedures is traditionally correlated with a center's surgical volume. Multiple single and multi-institutional studies conducted at large-volume centers have recently demonstrated improved survival following Norwood procedures. We report both short- and long-term outcomes at a single, small-volume institution and comment on factors potentially influencing outcomes at this institution.

METHODS

All patients undergoing Norwood procedures from January 1, 2005, to January 1, 2020, at our institution were included in this study. Kaplan-Meier survival and Cox regression risk factor analyses were performed in addition to first interstage risk factor scoring to compare observed versus expected survival.

RESULTS

The cohort included 113 patients. Kaplan-Meier freedom from death or transplant was 88%, 80%, and 76% at 1, 5, and 10 years, respectively. Freedom from death following hospital discharge after Norwood procedures was 94%, 87%, and 83% at 1, 5, and 10 years, respectively. The presence of genetic syndromes was a significant risk factor for mortality. First interstage observed-to-expected mortality following discharge was 0.57 (P = .04). Postoperative length of stay was comparable to that reported for the period 2015 to 2018 in the Society of Thoracic Surgeons Database.

CONCLUSIONS

Survival outcomes at this single, small-volume institution were similar to those reported by large-volume centers and multi-institutional collaborative studies. These results may be related to structural and functional features that have been demonstrated to influence outcomes in other studies. These factors are achievable by small-volume programs with sufficient resource allocation.

Norwood Procedure-Difficulty in Weaning From Cardiopulmonary Bypass and Implications for Outcomes

Difficulty weaning from cardiopulmonary bypass (CPB) or the need to return to CPB (collectively D-CPB) may occur after the Norwood procedure. We sought to evaluate the relationship between D-CBP and survival. This was a retrospective chart review of all patients undergoing a Norwood procedure at our institution during the interval 2005-2017. Primary outcome was survival for the Norwood procedure. Secondary outcomes included various measures of morbidity. Successful wean from CBP (S-CPB) was defined as no need to return to full-flow CPB during the initial definitive wean or after separation from CPB; otherwise, the classification was difficulty with wean (D-CBP). Successful rescue in the D-CPB group was defined as not requiring extracorporeal life support either in the operating room or within the first 3 postoperative days. Of the 196 patients in the cohort, 49 were D-CPB. Survival for S-CPB was 92.5% (136/147) vs 71.4% (35/49) for D-CPB (P = 0.001). Major morbidity occurred in 29.9% (44/147) in S-CPB vs 69.4% (34/49) in D-CPB (P < 0.001). With multivariable analysis, D-CPB was significantly associated with mortality (odds ratio = 8.09; confidence interval 2.72-24.05; P < 0.001). Successful rescue occurred in 30 of 49 patients in the D-CPB group and demonstrated survival similar to the S-CPB group. In the Norwood patient, D-CPB is an important intraoperative event and prognostic factor for mortality and morbidity. Successful rescue appears to ameliorate the impact of D-CPB on survival.

Structured review of post-cardiotomy extracorporeal membrane oxygenation: Part 2-pediatric patients

Veno-arterial extracorporeal membrane oxygenation (ECMO) is established therapy for short-term circulatory support for children with life-treating cardiorespiratory dysfunction. In children with congenital heart disease (CHD), ECMO is commonly used to support patients with post-cardiotomy shock or complications including intractable arrhythmias, cardiac arrest, and acute respiratory failure. Cannulation configurations include central, when the right atrium and aorta are utilized in patients with recent sternotomy, or peripheral, when cannulation of the neck or femoral vessels are used in non-operative patients. ECMO can be used to support any form of cardiac disease, including univentricular palliated circulation. Although veno-arterial ECMO is commonly used to support children with CHD, veno-venous ECMO has been used in selected patients with hypoxemia or ventilatory failure in the presence of good cardiac function. ECMO use and outcomes in the CHD population are mainly informed by single-center studies and reports from collated registry data. Significant knowledge gaps remain, including optimal patient selection, timing of ECMO deployment, duration of support, anti-coagulation, complications, and the impact of these factors on short- and long-term outcomes. This report, therefore, aims to present a comprehensive overview of the available literature informing patient selection, ECMO management, and in-hospital and early post-discharge outcomes in pediatric patients treated with ECMO for post-cardiotomy cardiorespiratory failure.

Predictors and outcomes of early post-operative veno-arterial extracorporeal membrane oxygenation following infant cardiac surgery

Background

We aimed to determine predictors of, and outcomes after, veno-arterial extracorporeal membrane oxygenation instituted within 48 h after cardiac surgery (early ECMO) in young infants.

Methods

Patients ≤ 6 weeks old having cardiac surgery from 2003 to 2012 were enrolled prospectively. Patients cannulated pre-operatively, intra-operatively, or ≥ 48 h post-operatively were excluded. Variables at p ≤ 0.1 on univariate regression were entered into multiple logistic regression to predict early ECMO. Early-ECMO cases were matched 1:2 for six demographic variables, and death by age 2 years old (determined using conditional logistic regression; presented as odds ratio (OR), 95% confidence interval (CI)) and General Adaptive Composite scores at age 2 years (determined using Wilcoxon rank sum) were compared; p ≤ 0.05 was considered statistically significant.

Results

Of 565 eligible patients over the 10-year period, 20 had early ECMO instituted at a mean (standard deviation) of 12.4 (11.4) h post-operatively, 10 of whom had extracorporeal cardiopulmonary resuscitation. Of early-ECMO patients, 8 (40%) were found to have residual anatomic defects requiring intervention with catheterization (n = 1) and/or surgery (n = 7). On multiple regression, the post-operative day 1 highest vasoactive-inotrope score (OR 1.02; 95%CI 1.06,1.08; p < 0.001), highest lactate (OR 1.2; 95%CI 1.06,1.35; p = 0.003), and lowest base deficit (OR 0.82; 95%CI 0.71,0.94; p = 0.004), CPB time (OR 1.01; 95%CI 1.00,1.02; p = 0.002), and single-ventricle anatomy (OR 5.35; 95%CI 1.66,17.31; p = 0.005) were associated with early ECMO. Outcomes at 2 years old compared between early-ECMO and matched patients were mortality 11/20 (55%) vs 11/40 (28%) (OR 3.22, 95%CI 0.98,10.63; p = 0.054) and General Adaptive Composite median 65 [interquartile range (IQR) 58, 81.5] in 9 survivors vs 93 [IQR 86.5, 102.5] in 29 survivors (p = 0.02).

Conclusions

The identified risk factors for, and outcomes after, having early ECMO may aid decision making in the acute period and confirm that neurodevelopmental follow-up for these children is necessary. The hypothesis that earlier institution of ECMO may improve long-term outcomes requires further study.

Mechanical Circulatory Support for Single Ventricle Failure

Mechanical circulatory support (MCS) for failing single ventricle (SV) physiology is a complex and challenging problem, which has not yet been satisfactorily addressed. Advancements in surgical strategies and techniques along with intensive care management have substantially improved the outcomes of neonatal palliation for SV physiology, particularly for hypoplastic left heart syndrome (HLHS). This is associated with a steady increase in the number of SV patients who are susceptible to develop heart failure (HF) and would potentially require MCS at a certain stage in their palliation. We have reviewed the literature regarding the reported modalities of MCS use in the management of SV patients. This includes analysis of various devices and strategies used for failing circulation at distinct stages of the SV pathway: after neonatal palliation, after the superior cavo-pulmonary connection (SCPC), and after total cavo-pulmonary connection (TCPC).

Outcomes of Extracorporeal Membrane Oxygenation in Children: An 11-Year Single-Center Experience in Korea

Background

Extracorporeal membrane oxygenation (ECMO) has become an important treatment modality in pediatric patients with cardiopulmonary failure, but few studies have been conducted in Korea.

Methods

We conducted a retrospective review of pediatric patients younger than 18 years who were placed on ECMO between January 2004 and December 2014 at Samsung Medical Center.

Results

We identified 116 children on ECMO support. The overall rate of successful weaning was 51.7%, and the survival to discharge rate was 37.1%. There were 39, 61, and 16 patients on ECMO for respiratory, cardiac, and extracorporeal cardiopulmonary resuscitation, respectively. The weaning rate in each group was 48.7%, 55.7%, and 43.8%, respectively. The survival rate was 43.6%, 36.1%, and 25.0%, respectively. Sixteen patients on ECMO had functional single ventricle physiology; in this group, the weaning rate was 43.8% and the survival rate was 31.3%. Ten patients were on ECMO as a bridge to transplantation (8 for heart and 2 for lung). In patients with heart transplantation, the rate of survival to transplantation was 50.0%, and the overall rate of survival to discharge was 37.5%.

Conclusion

An increasing trend in pediatric ECMO utilization was observed. The outcomes were favorable considering the early experiences that were included in this study and the limited supply of specialized equipment for pediatric patients.

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.

Setting Up an ECMO Program in a South American Country: Outcomes of the First 104 Pediatric Patients

BACKGROUND

Less than 1% of the extracorporeal life support organization (ELSO) registry patients are from South America. Extracorporeal membrane oxygenation (ECMO) is an expensive therapy not only in terms of direct financial cost but also with respect to technical and human resources. Finding a successful ECMO model that developing countries can afford is critical to the expansion of therapy to include the availability of this technology for patients in the developing world.

METHODS

We retrospectively studied the first 104 pediatric ECMO patients in the Fundacion Cardiovascular de Colombia between May 2007 and May 2013. We collected the ELSO registry data from electronic medical records to determine the survival rate, mortality risk factors, and complications in pediatric patients who received ECMO support for cardiac failure, respiratory failure, or ECMO for extracorporeal cardiopulmonary resuscitation in the setting of refractory cardiopulmonary resuscitation. We describe our model of ECMO care regarding staff, training process, care protocol, ECMO circuit, and costs.

RESULTS

Of 104 patients, 82 were diagnosed with congenital heart disease. Of those, 50 had biventricular and 32 had univentricular physiology, with a significantly higher survival rate at discharge in the biventricular group (44% vs 18.7%, odds ratio [OR] 3.6, 95% confidence interval [CI] = 1.28-10.52, P = .01). Pediatric patients with a cardiac indication had survival rates of 76.3% at weaning and 52.6% at discharge, which is roughly comparable to those reported by the ELSO in 2013. Univentricular physiology, ECPR, severe pre-ECMO acidosis, ECMO-associated renal failure, and duration of ECMO support were factors associated with increased mortality.

CONCLUSION

Despite limited availability of technical and economic resources, ECMO therapy can be done successfully in a developing country. A model of care based on nurses as ECMO specialists, supported by a multidisciplinary team, is cost-effective.

ECLS in Pediatric Cardiac Patients

Extracorporeal life support (ECLS) is an important device in the management of children with severe refractory cardiac and or pulmonary failure. Actually, two forms of ECLS are available for neonates and children: extracorporeal membrane oxygenation (ECMO) and use of a ventricular assist device (VAD). Both these techniques have their own advantages and disadvantages. The intra-aortic balloon pump is another ECLS device that has been successfully used in larger children, adolescents, and adults, but has found limited applicability in smaller children. In this review, we will present the "state of art" of ECMO in neonate and children with heart failure. ECMO is commonly used in a variety of settings to provide support to critically ill patients with cardiac disease. However, a strict selection of patients and timing of intervention should be performed to avoid the increase in mortality and morbidity of these patients. Therefore, every attempt should be done to start ECLS "urgently" rather than "emergently," before the presence of dysfunction of end organs or circulatory collapse. Even though exciting progress is being made in the development of VADs for long-term mechanical support in children, ECMO remains the mainstay of mechanical circulatory support in children with complex anatomy, particularly those needing rapid resuscitation and those with a functionally univentricular circulation. With the increase in familiarity with ECMO, new indications have been added, such as extracorporeal cardiopulmonary resuscitation (ECPR). The literature supporting ECPR is increasing in children. Reasonable survival rates have been achieved after initiation of support during active compressions of the chest following in-hospital cardiac arrest. Contraindications to ECLS have reduced in the last 5 years and many centers support patients with functionally univentricular circulations. Improved results have been recently achieved in this complex subset of patients.

Comparative Review of Outcomes in Patients With Congenital Heart Disease Requiring Cardiopulmonary Support for Failure to Wean From Cardiopulmonary Bypass or for Refractory Sudden Cardiac Arrest

Background:

We reviewed the outcomes of patients who underwent cardiopulmonary support (CPS) for either refractory sudden cardiac arrest or failure to wean from cardiopulmonary bypass (CPB).

Methods:

Between January 2005 and July 2013, 37 patients with congenital heart disease (CHD) underwent 39 instances of CPS for sudden cardiac arrest as extracorporeal cardiopulmonary resuscitation (E-CPR; group I, n = 19) or for failure to wean from CPB (group II, n = 20). Univariate analyses determined which variables differed among the groups and which had significant association with hospital survival. Binary logistic regression determined the significant associations in a multivariable model.

Results:

Overall 30-day and hospital survival were 76.9% (30) and 69.2% (27), respectively. For groups I and II, hospital survival was 68.4% (13) and 70.0% (14), respectively. Variables associated with mortality in the univariate analysis included hours on CPS ( P = .045), initial aspartate aminotransferase (AST) level on CPS ( P = .007), and bicarbonate 24 hours on CPS ( P = .004). Logistic regression showed single-ventricle physiology ( P = .05), initial AST level on CPS ( P = .03), and lower bicarbonate 24 hours on CPS ( P = .026) to be significantly associated with mortality.

Conclusions:

Comparable rates of survival to discharge can be obtained when CPS is initiated for E-CPR or for failure to wean from CPB in resuscitating patients with CHD. Hepatic and renal factors indicative of inadequate early tissue perfusion, single-ventricle physiology, and lower bicarbonate level are factors associated with poor outcome.

Troponin I levels in extracorporeal membrane oxygenation following congenital heart surgery

BACKGROUND

Correlating postcardiotomy extracorporeal membrane oxygenation (ECMO) troponin I (TnI) levels and outcomes.

METHODS

Between January 2006 and August 2010, 34 patients needed postcardiotomy ECMO for low cardiac output. Bailout ECMO was required either after unsuccessful weaning from bypass (n = 17, 50%), postoperatively from prolonged hemodynamic failure (n = 8, 23.5%), or following resuscitation (n = 9, 26.5%). The TnI levels were measured following surgery or resuscitation during 10 days and compared between survivors (group I) and non-survivors (group II).

RESULTS

Median support duration was seven days (range: 0-31). Surgery involving hypoplastic aortic arch repair (Norwood palliation; n = 7, 20.6%, or biventricular repair; n = 11, 32.4%) led to most ECMO runs. Successful weaning from ECMO and hospital survival were 76.5% and 50%, respectively. In group I, peak TnI levels were reached by 24 hours postoperatively, comparable to levels in group II (36 ± 34 vs 49 ± 38 ng/mL; P = .98). However, in group II, TnI levels formed a plateau by the second postoperative day, whereas group I showed a steep decline in TnI levels, suggesting myocardial recovery (P = .028). All patients (n = 4) who reached or maintained peak TnI levels at 48 hours died. On days 8, 9 and 10, TnI levels were significantly higher in group II (P = .024, .019, and .013, respectively).

CONCLUSIONS

Postcardiotomy ECMO was most commonly required after aortic arch repair. In the absence of ongoing myocardial insult due to ECMO hardware issues, coronary insufficiency or residual lesions, plateau TnI levels at 48 hours may seem to indicate an unfavorable outcome due to irreversible myocardial damage.

Late Outcomes of Infants Supported by Extracorporeal Membrane Oxygenation Following the Norwood Operation

Background:

Hospital survival for infants who require extracorporeal membrane oxygenation (ECMO) following the Norwood operation is 30% to 60%. However, little is known about late outcomes of hospital survivors and their ability to progress through subsequent palliative stages.

Methods:

Between 2002 and 2012, 38 (13.4%) of the 284 neonates with hypoplastic left heart syndrome or other single ventricle variants received ECMO support following Norwood. We examined factors affecting hospital death and compared postdischarge events between hospital survivors who received postoperative ECMO (n = 16 of 38) and a control of hospital survivors who did not receive ECMO (220 of 246).

Results:

Unplanned cardiac reoperation was the only predictor of postoperative ECMO requirement. Overall, 22 (58%) of the 38 patients were weaned from ECMO support and 16 (42%) of the 38 survived to hospital discharge. The ECMO duration was a significant factor for hospital mortality (odds ratio = 1.52 per 1-day increase [1.03-2.24], P = .035). Following discharge, 15 (94%) of the 16 underwent Glenn and 1 (6%) of the 16 had interstage mortality. In the control group, 194 (88%) of the 220 underwent Glenn and 26 (12%) of the 220 had interstage mortality or received transplantation ( P = .499). Following Glenn, 3 (20%) of the 15 patients had interstage mortality or received transplantation and 12 (80%) of the 15 proceeded to Fontan or were alive awaiting Fontan. In the control group, 23 (12%) of the 194 had interstage mortality or received transplantation and 171 (88%) proceeded to Fontan or were alive awaiting Fontan ( P = .357). Overall, 81% of hospital survivors were alive 5 years following discharge in both ECMO and non-ECMO groups.

Conclusions:

ECMO support following Norwood is associated with high probability of hospital death. Nonetheless, interstage mortality, progression to subsequent palliative stages, intermediate survival, and freedom from heart transplantation are comparable to those in patients who did not require postoperative ECMO support.

Extracorporeal Membrane Oxygenation in Single Ventricle Lesions Palliated Via the Hybrid Approach

Background:

Describing outcomes for children with hypoplastic left heart syndrome (HLHS) undergoing hybrid palliation (pulmonary artery band and stent placement in the patent ductus arteriosus) requiring extracorporeal membrane oxygenation (ECMO) support for cardiorespiratory failure.

Methods:

We reviewed the Extracorporeal Life Support Organization database for all patients with a diagnosis of an HLHS undergoing hybrid stage 1 palliation supported with ECMO and those patients with hybrid palliation supported with ECMO after comprehensive stage 2 palliation. Patients were identified using a combination of International Classification of Diseases, Ninth Revision and registry diagnosis and procedure codes. We report survival to hospital discharge and ECMO complications.

Results:

We identified 44 patients with HLHS requiring ECMO following stage 1 hybrid approach. Median age at cannulation was 13.5 days. Only 16% survived to hospital discharge. In all, 20 (50%) patients had a cardiac arrest prior to going onto ECMO and for 3 (19%) patients, ECMO was initiated during cardiopulmonary resuscitation.

Conclusions:

Overall survival for ECMO support in patients with HLHS palliated via the hybrid approach is very poor (16%) and is worse than 31% survival reported for ECMO after conventional stage 1 palliation. The reasons for these poor outcomes require further investigation.

Does Single Ventricle Physiology Affect Survival of Children Requiring Extracorporeal Membrane Oxygenation Support Following Cardiac Surgery?

Background:

Improved survival with postoperative extracorporeal membrane oxygenation (ECMO) has expanded its application to children with single ventricle (SV) anomalies. We examine current-era outcomes of postoperative ECMO with special focus on patients with SV.

Methods:

Demographic, anatomic, surgical, and support details of 100 consecutive children requiring postoperative ECMO (2007-2012) were included into multivariable regression models to identify factors affecting survival.

Results:

Median age was 73 days (4 days-16.2 years), 31 patients had SV physiology. The ECMO indication was failure to wean cardiopulmonary bypass (34%) and postoperative low cardiac output (66%) including 37% having extracorporeal cardiopulmonary resuscitation (ECPR). Median ECMO duration was four days (1-21). The ECMO decannulation and survival to hospital discharge were 62% and 37%. In SV group, decannulation and survival rates were 55% and 32%. The SV-ECMO outcomes were best in ECPR subgroup (54%), following shunt (57%) or Norwood (46%) and worst following Glenn, Fontan, or total anomalous pulmonary venous connection repair (0% survival). On multivariable analysis, factors affecting odds of survival were performing angiogram (odds ratio [OR]: 15.28, confidence interval [CI]: 2.34-99.89, P = .004), prolonged ECMO duration (OR: 0.64, CI: 0.47-0.88 per day, P = .005), leaving cannulation snares (OR: 28.41, CI: 2.65-304.70, P = .006), higher HCO3 (OR: 1.19, CI: 1.04-1.36, P = .01), renal failure requiring hemodialysis (OR: 0.21, CI: 0.06-0.76, P = .02), bleeding requiring re-exploration (OR: 0.21, CI: 0.06-0.75, P = .02), ECPR in patients with SV (OR: 11.84, CI: 1.11-126.07, P = .04), delayed lactate normalization (OR: 0.95, CI: 0.90-0.99 per hour, P = .02), and elevated liver enzymes (OR: 0.97, CI: 0.95-1.00 per 10 unit/L, P = .05).

Conclusions:

The ECMO is valuable in patients with SV however results depend on anatomy, procedure, and support indication. Persistent markers of poor perfusion, end-organ injury, and prolonged ECMO duration are associated with mortality. Those factors could be modified by early ECMO application before organ damage, meticulous homeostasis to ensure adequate perfusion, early diagnosis, and reoperation on residual lesions to expedite weaning.

Midterm survival of infants requiring postoperative extracorporeal membrane oxygenation after Norwood palliation

This study reports the mid-term survival for neonates undergoing extracorporeal membrane oxygenation (ECMO) after Norwood palliation at a single center. Limited data exist on the mid-term survival of patients undergoing ECMO after Norwood palliation. We reviewed our ECMO experience from July 1994 to October 2008 and compared two groups: patients who required ECMO after Norwood palliation and patients who underwent Norwood palliation without ECMO. We analyzed 30-day survival, survival to hospital discharge, and survival to most recent follow-up. One hundred sixty patients underwent Norwood palliation for hypoplastic left heart syndrome (HLHS) and its variants. A total of 32 patients (20%) required postoperative ECMO. Using Kaplan-Meier analysis, the predicted survival rates for Norwood/non-ECMO patients to 30 days, 1 year, and 3 years after the procedure are 87.6% (CI 79.5-91.5%), 62.5% (CI 54.3-71.0%), and 59.9% (CI 50.8-67.8%), respectively. Survival to 30 days, 1 year, and 3 years after Norwood was significantly decreased in Norwood/ ECMO patients, with predicted survival rates of 50.0% (CI 31.9-65.7%), 24.6% (CI 11.4-40.4), and 13.2% (CI 3.9-28.3%), respectively (p < 0.0001). Risk factors for hospital mortality included nonelective or emergency placement onto ECMO, longer duration of ECMO support, and the development of acute renal failure while on ECMO. Of the original Norwood/ECMO hospital survivors, only half of these patients survived a mean of nearly 4 years. ECMO after Norwood palliation is associated with significant mortality. Our data suggest that neonates who require ECMO after Norwood palliation are prone to continued attrition once discharged from the hospital.

Outcomes of infants weighing three kilograms or less requiring extracorporeal membrane oxygenation after cardiac surgery

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is the most common form of cardiac support for postcardiotomy cardiac failure in children. While its benefits have been thoroughly explored in infants weighing more than 3 kg, similar analyses are lacking in lower weight neonates. This single-center study investigated outcomes and risks for poor survival among infants weighing 3 kg or less.

METHODS

A retrospective review of infants 3 kg or less who required postcardiotomy ECMO support was performed (January 1, 1999 to December 31, 2010). Primary outcome was 30-day survival after decannulation. Factors analyzed for association with poor outcome included demographics, cardiac anatomy, bypass and circulatory arrest times, total ECMO support time, postoperative lactate, inotrope use, and need for renal replacement therapy.

RESULTS

During the study period, 64 patients weighing 3 kg or less required postcardiotomy ECMO. Median gestational age and age at ECMO initiation were 38 weeks (interquartile range, 36 to 39) and 7 days (interquartile range, 4 to 9), respectively, with median ECMO support time of 164 hours (interquartile range, 95 to 231). Overall 30-day survival after decannulation was 33%. Factors associated with poor outcome were longer duration of support (231 hours or more, 12% survival, versus less than 231 hours, 40% survival; p = 0.05) and renal replacement therapy (n = 36, survival 17% versus 54%; p = 0.002). Multivariable regression analysis identified renal replacement therapy as the only independent factor associated with poor survival (odds ratio 4.3, 95% confidence interval: 1.3 to 14.9, p = 0.02).

CONCLUSIONS

For infants weighing 3 kg or less, 30-day survival after decannulation after cardiac ECMO is poor. Factors associated with poor prognosis were need for renal replacement therapy and longer duration of ECMO support. These findings may provide a useful guide for medical decision making among this unique, high-risk patient group.

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.

Extracorporeal membrane oxygenation following Norwood stage 1 procedures at a single institution

Extracorporeal membrane oxygenation (ECMO) is an important circulatory assist for children with refractory cardiopulmonary dysfunction, but its role and indications after a stage 1 Norwood procedure are controversial. We assessed outcomes and risk factors in patients who underwent a Norwood palliation and ECMO at our institution. We retrospectively reviewed all patients who underwent a Norwood procedure and were supported with ECMO between January 1998 and January 2010. Of the 91 children who underwent a Norwood procedure during the study period, there were 15 postoperative runs of ECMO in 12 patients. The diagnoses of the patients included five with hypoplastic left heart syndrome, five with a hypoplastic left heart syndrome variant, and two with critical aortic stenosis. A total of four patients underwent bilateral pulmonary artery banding, and two patients underwent aortic valvuloplasty before the stage 1 Norwood procedure. The mean age of the patients was 28±30 days, and mean body weight was 2.6±0.5kg at the induction of ECMO. The indications for ECMO were low cardiac output in six children, circulatory collapse needing cardiopulmonary resuscitation in six children, and hypoxemia in three children. Five of the 12 patients were successfully weaned from ECMO. The significant risk factors for the inability to be weaned from ECMO were a history of circulatory collapse requiring cardiopulmonary resuscitation, and the induction of ECMO in the intensive care unit. Induction of ECMO may be considered earlier when hemodynamics are unstable in impaired patients following a stage 1 Norwood procedure to avoid circulatory collapse.

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.

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.

Indication for initiation of mechanical circulatory support impacts survival of infants with shunted single-ventricle circulation supported with extracorporeal membrane oxygenation

OBJECTIVES

The use of extracorporeal membrane oxygenation to support patients with shunted single-ventricle physiology has been controversial. Variable survivals are reported in a number of small case series. We sought to evaluate outcomes and identify predictors of survival for patients with shunted single-ventricle physiology who require extracorporeal membrane oxygenation support.

METHODS

We retrospectively reviewed the medical records of all patients aged less than 1 year with shunted single-ventricle physiology who were supported with extracorporeal membrane oxygenation at Children's Hospital Boston between 1996 and 2005. Survivors and nonsurvivors were compared with respect to demographics, diagnosis, operative variables, indication for extracorporeal membrane oxygenation, and extracorporeal membrane oxygenation variables.

RESULTS

Forty-four infants with shunted single-ventricle physiology were supported with extracorporeal membrane oxygenation. Diagnoses included hypoplastic left heart syndrome (24), other single-ventricle lesions (12), and pulmonary atresia/intact ventricular septum or a variant (8). Overall survival to discharge was 48%. Indication for extracorporeal membrane oxygenation was the strongest predictor of survival to discharge, with 81% of patients cannulated for hypoxemia but only 29% of those cannulated for hypotension surviving to discharge. Specifically, patients cannulated for shunt obstruction had the highest survival (83%).

CONCLUSIONS

Overall survival to discharge for patients with shunted single-ventricle physiology is similar to survival reported in the Extracorporeal Life Support Organization registry for all infants supported with cardiac extracorporeal membrane oxygenation. Thus, shunted single-ventricle physiology should not be considered a contraindication to extracorporeal membrane oxygenation. Patients cannulated for hypoxemia, particularly shunt thrombosis, had markedly improved survival compared with those supported primarily for hypotension/cardiovascular collapse. Survival did not differ depending on anatomic diagnosis.

Modified CPB circuit for postoperative rescue of high-risk patients following cardiac repair: are we keeping safe?

Extracorporeal membrane oxygenation (ECMO) is commonly used to treat postcardiotomy cardiopulmonary dysfunction in small children. System readiness, need for additional blood products, and exposure to new surfaces are important considerations, particularly when used for resuscitation. We reviewed our experience with a cardiopulmonary bypass (CPB) system modified to provide extended circulatory support system after surgery in patients considered at high risk. When not used in the operating room, the system was recirculated for 24 hours. Before being discarded, blood samples were obtained for activated clotting time, arterial blood gas, and blood cultures from 10 circuits. Between January 2004, and December 2005, 44 patients underwent cardiac repair using this CPB system. ECMO support was initiated in the operating room in 8 patients, and six circuits were used after patient arrival in the intensive care unit. Blood sampling after 24 hours on standby circuits revealed acceptable values for pH, Pao2, hematocrit, ionized calcium, potassium level, and ACT. All blood cultures were negative at 5 days. Survival for patients who received a circuit on standby was 64%.This modified cardiopulmonary circuit can be transformed into a simple, safe, and effective ECMO support system. Deployment of a CPB circuit previously used for cardiac repair has many advantages and maximizes utilization of resources.

Intensive care course after stage 1 Norwood procedure: are there early predictors of failure?

OBJECTIVE

The purpose of this study was to review the early postoperative course of stage 1 Norwood with Blalock-Taussig shunt (BTS) or right ventricle-to-pulmonary artery conduit (RVPA) and to identify early predictors of failure.

MATERIAL AND METHODS

A retrospective analysis was conducted in 33 consecutive neonates who underwent BTS (n=19) or RVPA (n=14) stage 1 Norwood procedure between 2000 and 2005. Pre-, peri-, and postoperative data included: hourly hemodynamics and blood gases, pulmonary to systemic flow ratio, duration of mechanical ventilatory and inotrope support, intensive care and hospital stay. Failure was defined as death or transplantation.

RESULTS

Thirteen patients failed the procedure (39.4%): 10 BTS (52.6%) and 3 RVPA (21.4%). Failure decreased from 61.1% in 2000-2002 to 13.3% in 2003-2005 and was associated with: low systolic, mean and diastolic blood pressure, urine output, pH, base excess, bicarbonates, and high pulmonary to systemic flow ratio within 24 h postoperatively. Arterial oxygen and CO2 pressure, and oxygen saturation did not differ with failure. RVPA had higher diastolic blood pressure and more stable hemodynamics despite similar pulmonary to systemic flow ratio. Duration of mechanical ventilation, inotrope support, intensive care stay were shorter in RVPA. Postoperative echographic ventricular dysfunction and tricuspid regurgitation grade were correlated with failure.

CONCLUSIONS

Excessive pulmonary to systemic flow ratio and low blood pressure are associated with failure. High diastolic blood pressure more than low pulmonary to systemic flow ratio seems to account for more favorable outcomes in RVPA compared to BTS procedure.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) in pediatric cardiac support

BACKGROUND

Resuscitation extracorporeal membrane oxygenation (R-ECMO) was introduced at our institution in July 2002. We reviewed the use of venoarterial (VA)-ECMO for cardiac diagnoses at our institution.

METHODS

Retrospective analysis of patients on VA-ECMO for cardiac failure was performed. Survival was defined as discharge from hospital.

RESULTS

Twenty-seven patients were supported with VA-ECMO (median age, 27 days; range, 1 to 640 days; median weight, 3.8 kg; range, 1.8 to 11.3 kg). Diagnoses were cardiomyopathy-myocarditis (CMM) in 8 (30%), systemic-to-pulmonary artery shunt-dependent single ventricle (SV) in 12 (44%), postcardiotomy for biventricular repair (BiV) in 6 (22%), and arrhythmia in 1 (4%). Sixteen of 27 patients survived (59%). Seven of 8 CMM patients survived (88%); 6 (75%) bridged to cardiac recovery, 1 to transplant (13%), and 1 death (13%). Seven of 12 SV patients survived (58%). The SV ECMO indications: post-Norwood ventricular dysfunction (n = 3, 2 deaths), postoperative cardiac failure (n = 6, 2 deaths), respiratory failure (n = 1, 1 death), and acute shunt occlusion (n = 2, 0 deaths). One of 6 BiV patients survived (17%). The BiV ECMO indications: failure to wean from CPB (n = 3, 3 deaths), postoperative cardiac failure (n = 2, 2 deaths), and pulmonary hypertension (n = 1, 0 deaths). Fifteen patients (56%) underwent cardiopulmonary resuscitation during ECMO cannulation. Eleven of 15 R-ECMO patients (73%) survived versus 5 of 12 non-R-ECMO patients (42%, p = 0.13). Median duration of R-ECMO: 66 hours (range, 18 to 179) versus 145 hours (range, 43 to 986, p = 0.01) for non-R-ECMO.

CONCLUSIONS

Resuscitation extracorporeal membrane oxygenation is an appropriate application in pediatric patients with cardiac disease. Single ventricle patients experiencing cardiopulmonary collapse and CMM patients have favorable outcomes. Failure to wean from CPB and postoperative ventricular failure are higher risk indications.

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.

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.

Effects of Circuit Miniaturization in Reducing Inflammatory Response to Infant Cardiopulmonary Bypass by Elimination of Allogeneic Blood Products

Conventional neonatal cardiopulmonary bypass requires the use of large volumes of allogeneic blood to prevent unacceptable hemodilution. Evidence is accumulating to suggest that the use of blood products during cardiopulmonary bypass has a negative effect on clinical recovery through inflammatory side effects. This would suggest an advantage for eliminating blood use in infant cardiopulmonary bypass through circuit miniaturization. In this article, we review the data supporting this rationale and provide the results from studies in our laboratory that emphasize the benefits of circuit miniaturization.

Extracorporeal life support after staged palliation of a functional single ventricle: Subsequent morbidity and survival

OBJECTIVE

We sought to review the outcome of infants with a functional single ventricle receiving postoperative extracorporeal life support.

METHODS

We reviewed all patients with a functional single ventricle receiving postoperative extracorporeal life support between January 1997 and May 2003.

RESULTS

We supported 25 infants (age range, 2-139 days; median age, 15 days; weight range, 1.9-5.9 kg; median weight, 3.4 kg) with extracorporeal life support. Operative procedures were Norwood stage 1 procedure in 18 patients, modified Blalock-Taussig shunt in 4 patients, bidirectional superior cavopulmonary shunt in 2 patients, and pulmonary vein repair in 1 patient. Indications for extracorporeal life support included cardiac arrest (14/25) and low cardiac output state (11/25). Extracorporeal membrane oxygenation was initiated in 19 patients, with conversion to a ventricular assist device in 7 patients. Ventricular assist device alone was initiated in 6 patients. Survival to decannulation was 76%, with 5 late deaths from multiorgan failure and 56% intensive care unit survival. Survival to hospital discharge was 44%. On univariate analysis, the presence of arrhythmia before extracorporeal life support (P = .005), renal failure (P = .0007), Candida species-induced sepsis (P = .026), and multiorgan failure (P = .0009) were significant risk factors in the nonsurvivors. Median hospital stay was 43.5 days (range, 6-181 days) for the whole group and 93 days (range, 36-181 days) for survivors. Eight patients completed next stage palliation.

CONCLUSIONS

Twenty percent of patients were supported with a ventricular assist device alone, with 50% conversion to a ventricular assist device from extracorporeal membrane oxygenation. Survival to decannulation was encouraging. Multiorgan failure and risk of invasive infection in the post-extracorporeal membrane oxygenation period mitigate against survival to hospital discharge. Use of extracorporeal life support before cardiac arrest might reduce attrition between decannulation and hospital discharge.

Perioperative management of patients with poorly functioning ventricles in the setting of the functionally univentricular heart

The patient with a functionally univentricular heart is at increased risk for ventricular dysfunction for a variety of reasons. At birth, the pulmonary and systemic circulations are in parallel, leading to pulmonary overcirculation and a volume-loaded functional ventricle. Significant atrioventricular valvar regurgitation, abnormal ventriculoarterial coupling, diastolic dysfunction, and altered ventricular geometry can also contribute to long-term ventricular dysfunction. These collected circumstances place the patient at increased risk for perioperative morbidity and mortality. We will discuss in this review the pathophysiology that leads to ventricular dysfunction at each stage of surgical palliation, as well as the strategies for perioperative management. In addition, we will highlight novel strategies for management of ventricular dysfunction.

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.

Coupling Pediatric Ventricle Assist Devices to the Fontan Circulation: Simulations with a Lumped-Parameter Model

In pediatric ventricular assist device (VAD) design, the process of matching device characteristics and dimensions to the relevant disease conditions poses a formidable challenge because the disease spectrum is more highly varied than for adult applications. One example arises with single-ventricle congenital defects, which demand palliative surgeries that create elevated systemic venous pressure and altered pulmonary hemodynamics. Substituting a mechanical pump as a right ventricle has long been proposed to eliminate the associated early and postoperative anomalies. A pulsatile lumped-parameter model of the single-ventricle circulation was developed to guide the preliminary design studies. Two special modules, the pump characteristics and the total cavopulmonary connection (TCPC) module, are introduced. The TCPC module incorporates the results of three-dimensional patient-specific computational fluid dynamics calculations, where the pressure drop in the TCPC anastomosis is calculated at the equal vascular lung resistance operating point for different cardiac outputs at a steady 60/40 inferior vena cava/superior vena cava flow split. Preliminary results obtained with the adult parameters are presented with no ventricle remodeling or combined larger-size single ventricle. A detailed literature review of single-ventricle function is provided. Coupling a continuous pump to the single-ventricle circulation brought both the pulmonary and systemic venous pressures back to manageable levels. Selected VADs provided an acceptable cardiac output trace of the single left ventricle, after initial transients. Remodeling of the systemic venous compliance plays a critical role in performance and is included in this study. Pulsatile operation mode with rotational speed regulation highlighted the importance of TCPC and pulmonary artery compliances. Four different pumps and three patient-specific anatomical TCPC pathologies were studied. Magnitudes of the equivalent TCPC resistances were found to be comparable to the vascular resistances of the normal baseline circulation, significantly affecting both the VAD design and hemodynamics.

Extracorporeal Life Support in Neonates, Infants, and Children After Repair of Congenital Heart Disease: Modern Era Results in a Single Institution

BACKGROUND

Extracorporeal life support has assumed a very effective role in the support of patients with refractory heart failure after repair of congenital heart disease, with hospital survival between 37% and 42%. We reviewed our results of different applications of extracorporeal life support in the last 2 years.

METHODS

Between January 2001 and October 2003, 671 patients underwent surgery for congenital heart disease at our institution. We retrospectively reviewed the hospital and clinic charts of the patients who required extracorporeal life support postoperatively, and studied the factors associated with survival.

RESULTS

Thirty-six patients (5.36%) received extracorporeal life support after surgery, between 1 day and 8 years of age (age < 30 days, n = 34). We divided the patients into four groups. Group 1 consisted of 13 patients who were electively placed on ventricular support without an oxygenator (univentricular assist device) after repair of single-ventricle disease. Group 2 consisted of 16 patients who required extracorporeal membrane oxygenation after surgery for failed hemodynamics. Group 3 consisted of 2 patients who required left ventricle support (left ventricular assist device) after surgery for two-ventricle disease but who did not require biventricular (extracorporeal membrane oxygenation) support. Group 4 consisted of 5 patients who required conversion from ventricular assist device to extracorporeal membrane oxygenation. Overall, 28 patients were weaned successfully (78%), and 24 survived to discharge (67%). Hospital survival in groups 1, 2, 3, and 4 was 100%, 50%, 100%, and 20%, respectively. Univariate factors associated with survival were age, weight, ventricular assist device type, duration, single-ventricle disease, reexploration, number of complications, and specific complications such as sepsis, renal failure, and pulmonary failure.

CONCLUSIONS

Extracorporeal life support utilization was expanded to include different applications with different outcomes. The extracorporeal life support registry should be altered to reflect those changes.

The intensive care of infants with hypoplastic left heart syndrome

Until a little over two decades ago, hypoplastic left heart syndrome was considered an inoperable and fatal condition, with most deaths occurring in early infancy, and almost all of those affected dying before their first birthday. However, the advent of surgical palliation and advances in peri-operative care, have offered hope to these patients and their families.

Utilization and outcomes of neonatal cardiac extracorporeal life support: 1996-2000

OBJECTIVES

Extracorporeal life support for neonatal respiratory failure has decreased, but utilization and outcome of cardiac extracorporeal life support are not well characterized. Among neonates born 1996-2000, our objects were to evaluate changes in utilization and outcome of cardiac extracorporeal life support and characterize correlates of survival.

DESIGN

Retrospective analysis of Extracorporeal Life Support Organization Registry data.

SETTING

Intensive care units participating in the ELSO registry.

PATIENTS

Patients placed on extracorporeal life support for center-specified "cardiac support" at </=30 days of age from 1996 to 2000. Patients with hypoplastic left heart syndrome were also analyzed separately.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient characteristics and correlates of survival to discharge or transfer were analyzed by chi-square, Student's t-test, and logistic regression analysis. Neonates placed on cardiac extracorporeal life support increased from 112 in 1996 to 200 in 2000 (total n = 740). Overall survival was 34.2%: 28% for hypoplastic left heart syndrome and 35.4% for nonhypoplastic left heart syndrome. For the overall group, no significant correlations were found between survival and year on extracorporeal life support, multiple runs, or diagnosis of hypoplastic left heart syndrome. Diagnoses of transposition of the great arteries (p = .03) or persistent pulmonary hypertension of the neonate (p = .004) and extracorporeal life support at <3 days (p = .003) were associated with higher survival. Survivors had fewer mean extracorporeal life support hours (125.5 +/- 121.4 vs. 159.0 +/- 127.6, p = .0006). Logistic regression confirmed significant bivariate findings. A total of 118 hypoplastic left heart syndrome patients were reported from 1996 to 2000. Extracorporeal life support at >15 days was associated with improved survival among hypoplastic left heart syndrome patients (p = .03), and survivors had fewer mean extracorporeal life support hours (89.3 +/- 52.3 vs. 147.5 +/- 129.7, p = .015). Logistic regression showed that only greater number of hours on extracorporeal life support was independently associated with nonsurvival.

CONCLUSIONS

Neonatal cardiac extracorporeal life support use increased substantially from 1996 to 2000, with survival to discharge or transfer in more than one third of patients. Hypoplastic left heart syndrome was not associated with nonsurvival. Fewer hours on extracorporeal life support, diagnoses of persistent pulmonary hypertension of the neonate and transposition of the great arteries, and extracorporeal life support at <3 days were associated with survival.

Fresh whole blood versus reconstituted blood for pump priming in heart surgery in infants

BACKGROUND

In an attempt to reduce the coagulopathic and inflammatory responses seen after cardiopulmonary bypass, the use of fresh whole blood during heart operations has become the standard of care for neonates and infants at many institutions. We compared the use of fresh whole blood with the use of a combination of packed red cells and fresh-frozen plasma (reconstituted blood) for priming of the cardiopulmonary bypass circuit.

METHODS

We conducted a single-center, randomized, double-blind, controlled trial involving children less than one year of age who underwent open-heart surgery. Patients were assigned to receive either fresh whole blood that had been collected not more than 48 hours previously (96 patients) or reconstituted blood (104 patients) for bypass-circuit priming. Clinical outcomes and serologic measures of systemic inflammation and myocardial injury were compared between the groups.

RESULTS

The group that received reconstituted blood had a shorter stay in the intensive care unit than the group that received fresh whole blood (70.5 hours vs. 97.0 hours, P=0.04). The group that received reconstituted blood also had a smaller cumulative fluid balance at 48 hours (-6.9 ml per kilogram of body weight vs. 28.8 ml per kilogram, P=0.003). Early postoperative chest-tube output, blood-product transfusion requirements, and levels of serum mediators of inflammation and cardiac troponin I were similar in the two groups.

CONCLUSIONS

The use of fresh whole blood for cardiopulmonary bypass priming has no advantage over the use of a combination of packed red cells and fresh-frozen plasma during surgery for congenital heart disease. Moreover, circuit priming with fresh whole blood is associated with an increased length of stay in the intensive care unit and increased perioperative fluid overload.

Cardiac ECMO for biventricular hearts after paediatric open heart surgery

OBJECTIVE

To delineate predictors of hospital survival in a large series of children with biventricular physiology supported with extracorporeal membrane oxygenation (ECMO) after open heart surgery.

RESULTS

81 children were placed on ECMO after open heart surgery. 58% (47 of 81) were transferred directly from cardiopulmonary bypass to ECMO. Hospital survival was 49% (40 of 81) but there were seven late deaths among these survivors (18%). Factors that improved the odds of survival were initiation of ECMO in theatre (64% survival (30 of 47)) rather than the cardiac intensive care unit (29% survival (10 of 34)) and initiation of ECMO for reactive pulmonary hypertension. Important adverse factors for hospital survival were serious mechanical ECMO circuit problems, renal support, residual lesions, and duration of ECMO.

CONCLUSIONS

Hospital survival of children with biventricular physiology who require cardiac ECMO is similar to that found in series that include univentricular hearts, suggesting that successful cardiac ECMO is critically dependent on the identification of hearts with reversible ventricular dysfunction. In our experience of postoperative cardiac ECMO, the higher survival of patients cannulated in the operating room than in the cardiac intensive care unit is due to early effective support preventing prolonged hypoperfusion and the avoidance of a catastrophic cardiac arrest.

Use of routine ventricular assist following the first stage Norwood procedure

Surgical treatment of hypoplastic left heart syndrome has generated substantial interest and attention amongst cardiac surgeons since the initial reports from Norwood and his colleagues in 1980.1,2 Initial efforts at most programmes were to create reproducible results, and mortality rates remained high at several institutions throughout the 1980s and 1990s. A recent multi-institutional review demonstrates that the hospital mortality still remains high in numerous centers at the current time.3 Nevertheless, several advances over recent years have led to improved outcomes, and in the best centers, hospital survival now approaches 90%. Survival in successful centers is claimed to relate to the ability of the team to help the patient balance the systemic and pulmonary flows of blood. This ability to balance flow has been enhanced, over recent years, by numerous contributions, including decreasing the size of shunt ordinarily used,4 the use of alpha blockade,5 the rapid deployment of extracorporeal membrane oxygenation,6–8 and various forms of ventilatory manipulation.