Preferential use of venovenous extracorporeal membrane oxygenation for congenital diaphragmatic hernia

Discontinuation of the OriGen® Dual-lumen Right Atrial Cannula Decreased Venovenous ECMO Usage in Neonates and Older Children: A Survey of the American Pediatric Surgical Association

INTRODUCTION

Dual-lumen cannulas for venovenous (VV)-ECMO are widely used in pediatric patients. The popular OriGen® dual-lumen right atrial cannula was discontinued in 2019 without a comparable replacement.

METHODS

A survey covering VV-ECMO practice and opinions was distributed to attending members of the American Pediatric Surgical Association.

RESULTS

137 pediatric surgeons responded (14%). Prior to discontinuation of the OriGen®, 82.5% offered VV-ECMO to neonates, and 79.6% cannulated with the OriGen®. Following its discontinuation, those that offered only venoarterial (VA)-ECMO to neonates increased to 37.6% from 17.5% (p = 0.0002). An additional 33.8% changed their practice to sometimes use VA-ECMO when VV-ECMO was indicated. Reasons for not incorporating dual-lumen bi-caval cannulation into practice included risk of cardiac injury (51.7%), inexperience with bi-caval cannulation in neonates (36.8%), difficulty with placement (31.0%), and recirculation and/or positioning problems (27.6%). For the pediatric/adolescent population, 95.5% of surgeons offered VV-ECMO prior to OriGen® discontinuation. Few switched to exclusive VA-ECMO (1.9%) when the OriGen® was discontinued, but 17.8% of surgeons began to incorporate selective use of VA-ECMO.

CONCLUSION

Discontinuation of the OriGen® cannula drove pediatric surgeons to alter their cannulation practices, dramatically increasing VA-ECMO use for neonatal and pediatric respiratory failure. These data may suggest a need for targeted education accompanying major technological shifts.

LEVEL OF EVIDENCE

Level IV.

Outcomes after Extracorporeal Membrane Oxygenation in Neonates with Congenital Diaphragmatic Hernia: A Single-Center Experience

Background

Congenital diaphragmatic hernia (CDH) is a rare disease often requiring mechanical ventilation after birth. In severe cases, extracorporeal membrane oxygenation (ECMO) may be needed. This study analyzed the outcomes of patients with CDH treated with ECMO and investigated factors related to in-hospital mortality.

Methods

Among 254 newborns diagnosed with CDH between 2008 and 2020, 51 patients needed ECMO support. At Asan Medical Center, a multidisciplinary team approach has been applied for managing newborns with CDH since 2018. Outcomes were compared between hospital survivors and nonsurvivors.

Results

ECMO was established at a median of 17 hours after birth. The mean birth weight was 3.1±0.5 kg. Twenty-three patients (23/51, 45.1%) were weaned from ECMO, and 16 patients (16/51, 31.4%) survived to discharge. The ECMO mode was veno-venous in 24 patients (47.1%) and veno-arterial in 27 patients (52.9%). Most cannulations (50/51, 98%) were accomplished through a transverse cervical incision. No significant between-group differences in baseline characteristics and prenatal indices were observed. The oxygenation index (1 hour before 90.0 vs. 51.0, p=0.005) and blood lactate level (peak 7.9 vs. 5.2 mmol/L, p=0.023) before ECMO were higher in nonsurvivors. Major bleeding during ECMO more frequently occurred in nonsurvivors (57.1% vs. 12.5%, p=0.007). In the multivariate analysis, the oxygenation index measured at 1 hour before ECMO initiation was identified as a significant risk factor for in-hospital mortality (odds ratio, 1.02; 95% confidence interval, 1.01–1.04; p=0.05).

Conclusion

The survival of neonates after ECMO for CDH is suboptimal. Timely application of ECMO is crucial for better survival outcomes.

Management preferences in ECMO mode for congenital diaphragmatic hernia

PURPOSE

The purpose of this study was to identify management preferences that may exist in the care of infants with CDH receiving ECMO with emphasis on VV-ECMO.

METHODS

A survey was created to measure treatment preferences regarding ECMO use in CDH. The survey was distributed to all APSA and ELSO/Euro-ELSO members via e-mail. Survey results were summarized using descriptive statistics.

RESULTS

The survey had 230 respondents. The survey participants were surgeons (75%), neonatologists/intensivists (23%), and "other" (2%). The mean annual center volume was 11.6(±9.6) CDH cases, and the average number treated with ECMO was 4.5 (±6.4) cases/yr. The most agreed upon criteria for ECMO initiation were preductal O₂ saturation <80% refractory to ventilator manipulation and medical therapy (89%), oxygenation index >40 (80%), severe air-leak (79%), and mixed acidosis (75%). Over 60% of respondents agreed the VV-ECMO would be optimum for average risk neonates. However, this preference diminished as the pre-ECMO level of cardiac support increased. When asked about why each respondent would choose VA-ECMO over VV-ECMO, the responses varied significantly between surgeons and non-surgeons.

CONCLUSION

While there seem to be areas of consensus among practitioners, such as criteria for initiation of ECMO, this survey revealed substantial variation in individual practice patterns regarding the use of ECMO for CDH.

TYPE OF STUDY

Qualitative, Survey.

LEVEL OF EVIDENCE

IV.

Outcomes of infants with congenital diaphragmatic hernia treated with venovenous versus venoarterial extracorporeal membrane oxygenation: A propensity score approach

PURPOSE

Previous studies comparing extracorporeal membrane oxygenation (ECMO) modality for congenital diaphragmatic hernia (CDH) have not accounted for confounding by indication. We therefore hypothesized that using a propensity score (PS) approach to account for selection bias may identify outcome differences based on ECMO modality for infants with CDH.

METHODS

We utilized ELSO Registry data (2000-2016). Patients with CDH were divided to either venoarterial (VA) or venovenous (VV) ECMO. Patients were matched by PS to control for nonrandom treatment assignment. Subgroup analyses were conducted based on timing of CDH repair relative to ECMO. Primary analysis was the "intent-to-treat" cohort based on the initial ECMO mode. Mortality was the primary outcome, and severe neurologic injury (SNI) was a secondary outcome.

RESULTS

PS matching (3:1) identified 3304 infants (VA = 2470, VV = 834). In the main group, mortality was not different between VA and VV ECMO (OR = 1.01, 95% CI: 0.86-1.18) and there was no difference in SNI between VA and VV (OR = 0.80; 95% CI: 0.63-1.01). For the pre-ECMO CDH repair subgroup, 175 VA cases were matched to 70 VV. In these neonates, mortality was higher for VV compared to VA (OR = 2.10, 95% CI: 1.19-3.69), without any difference in SNI (OR = 1.48; 95% CI: 0.59-3.71). For the subgroup that did not have pre-ECMO CDH repair, 2030 VA cases were matched to 683 VV cases. In this subgroup, VV was associated with 27% lower risk of SNI relative to VA (OR = 0.73, 95% CI: 0.56-0.95) without any difference in mortality (OR = 0.94, 95% CI: 0.79-1.11).

CONCLUSION

This study revalidates that ECMO mode does not significantly affect mortality or SNI in infants with CDH. In the subset of infants who require pre-ECMO CDH repair, VA favors survival, whereas, in the subgroup of infants that did not have pre-ECMO CDH repair, VV favors lower rates of SNI. We conclude that neither mode appears consistently superior across all situations, and clinical judgment should remain a multifactorial decision.

LEVEL OF EVIDENCE

Level III.

The potential of accurate SVO2 monitoring during venovenous extracorporeal membrane oxygenation: an in vitro model using ultrasound dilution

Introduction. Some degree of recirculation occurs during venovenous extracorporeal membrane oxygenation (VV ECMO) which, (1) reduces oxygen (O2) delivery, and (2) renders venous line oxygen saturation monitoring unreliable as an index of perfusion adequacy. Ultrasound dilution allows clinicians to rapidly monitor and quantify the percent of recirculation that is occurring during VV ECMO. The purpose of this paper is to test whether accurate patient mixed venous oxygen saturation (SVO2) can be calculated once recirculation is determined. It is hypothesized that it is possible to derive patient mixed venous saturations by integrating recirculation data with the ECMO circuit arterial and venous line oxygen saturation data. Methods. A test system containing sheep blood adjusted to three venous saturations (low-30%, med-60%, high-80%) was interfaced via a mixing chamber with a standard VV ECMO circuit. Recirculation, arterial line and venous line oxygen saturations were measured and entered into a derived equation to calculate the mixed venous saturation. The resulting value was compared to the actual mixed venous saturation. Results. Recirculation was held constant at 30.5 ± 2.0% for all tests. A linear regression comparison of “actual” versus “calculated” mixed venous saturations produced a correlation coefficient of R2 = 0.88. Direct comparison of actual versus calculated saturations for all three test groups respectively are as follows; Low: 31.8 ± 3.95% vs. 37.0 ± 6.7% (NS), Med: 61.7 ± 1.5% vs. 72.3 ± 1.8% (p < 0.05), High: 84.4 ± 0.9% vs. 91.2 ± 1.1% (p < 0.05). Discussion. There was a strong correlation between actual and calculated mixed venous saturations; however, significant differences between actual and calculated values where observed at the Med and High groups. While this data suggests that using quantified recirculation data to calculate SVO2 is promising, it appears that a straightforward derivative of the oxygen saturation-based equation may not be sufficient to produce clinically accurate calculations of actual mixed venous saturations. Perfusion (2007) 22, 239—244.

Successful primary use of VVDL+V ECMO with cephalic drain in neonatal respiratory failure

OBJECTIVE

To describe the use of double-lumen venovenous (VVDL) extracorporeal membrane oxygenation (ECMO) with cephalic draining cannula (VVDL+V) as a primary approach for all neonatal respiratory diagnoses and to compare our single-center experience with data as collected in the Extracorporeal Life Support Organization (ELSO) database.

STUDY DESIGN

We retrospectively reviewed all cases of ECMO for neonatal respiratory failure performed in the neonatal intensive-care unit at a large referral children's hospital, the Children's Healthcare of Atlanta at Egleston (CHOA-E). Comparisons were then made to neonatal respiratory ECMO data retrieved from the ELSO database.

RESULTS

At CHOA-E 162 of 189 cases were completed with the VVDL+V approach. Survival in the VVDL+V cohort was 89.1% versus 68.7% from ELSO, P<0.001. For those complications considered, the overall risk of complication favored the CHOA-E VVDL+V group as compared with ELSO (odds ratio (OR) 0.71 (0.52-0.7)) as did the risk of neurologic complications (OR 0.29, (0.15-0.58)), including intracranial hemorrhage (OR 0.39 (0.18-0.97), P=0.011).

CONCLUSION

The VVDL+V approach can be used successfully as the primary approach for ECMO for neonatal respiratory failure of various etiologies and in this single-center cohort this approach was associated with improved survival and lower rates of complication as compared with the ELSO database.

Management of congenital diaphragmatic hernia: A systematic review from the APSA outcomes and evidence based practice committee

OBJECTIVE

Variable management practices complicate the identification of optimal strategies for infants with congenital diaphragmatic hernia (CDH). This review critically appraises the available evidence to provide recommendations.

METHODS

Six questions regarding CDH management were generated. English language articles published between 1980 and 2014 were compiled after searching Medline, Cochrane, Embase and Web of Science. Given the paucity of literature on the subject, all studies irrespective of their rank in the levels of evidence hierarchy were included.

RESULTS

Gentle ventilation with permissive hypercapnia provides the best outcomes. Initial high frequency ventilation may be considered but its overall efficacy is unproven. Routine inhaled nitric oxide (iNO) or other medical adjuncts for acute, severe pulmonary hypertension demonstrate no benefit. Evidence does not support routine administration of pre- or postnatal glucocorticoids. Mode of extracorporeal membrane oxygenation (ECMO) has little bearing on outcomes. While the overall timing of repair does not impact outcomes, early repair on ECMO has benefits. Open repair leads to significantly fewer recurrences. Polytetrafluoroethylene (PTFE) is the most durable patch repair material.

CONCLUSIONS

Limited high-level evidence prevents the development of robust management guidelines for CDH. Prospective, multi-institutional studies are needed to identify best practices and optimize outcomes.

Acute Neonatal Respiratory Failure

Acute respiratory failure requiring assisted ventilation is one of the most common reasons for admission to the neonatal intensive care unit. Respiratory failure is the inability to maintain either normal delivery of oxygen to the tissues or normal removal of carbon dioxide from the tissues. It occurs when there is an imbalance between the respiratory workload and ventilatory strength and endurance. Definitions are somewhat arbitrary but suggested laboratory criteria for respiratory failure include two or more of the following: PaCO₂ > 60 mmHg, PaO₂ < 50 mmHg or O₂ saturation <80 % with an FiO₂ of 1.0 and pH < 7.25 (Wen et al. 2004).

A novel rotary pulsatile flow pump for cardiopulmonary bypass

It has been suggested that pulsatile blood flow is superior to continuous flow (CF) in cardiopulmonary bypass (CPB). However, adoption of pulsatile flow (PF) technology has been limited because of practicality and complexity of creating a consistent physiologic pulse. A pediatric pulsatile rotary ventricular pump (PRVP) was designed to address this problem. We evaluated the PRVP in an animal model and determined its ability to generate PF during CPB. The PRVP (modified peristaltic pump, with tapering of the outlet of the pump chamber) was tested in four piglets (10-12 kg). Cannulation was performed with right atrial and aortic cannulae, and pressure sensors were inserted into the femoral arteries. Pressure curves were obtained at different levels of flow and compared with both the animal's baseline physiologic function and a CF roller pump. Pressure and flow waveforms demonstrated significant pulsatility in the PRVP setup compared with CF at all tested conditions. Measurement of hemodynamic energy data, including the percentage pulsatile energy and the surplus hydraulic energy, also revealed a significant increase in pulsatility with the PRVP (p < 0.001). The PRVP creates physiologically significant PF, similar to the pulsatility of a native heart, and has the potential to be easily implemented in pediatric CPB.

Controversies in the management of severe congenital diaphragmatic hernia

Despite years of progress in perinatal care, severe congenital diaphragmatic hernia (CDH) remains a clinical challenge. Controversies include almost every facet of clinical care: the definition of severe CDH by prenatal and postnatal criteria, fetal surgical intervention, ventilator management, pulmonary hypertension management, use of extracorporeal membrane oxygenation, surgical considerations, and long-term follow-up. Breakthroughs are likely only possible by sharing of experience, collaboration between institutions and innovative therapies within well-designed multicenter clinical trials.

Outcomes comparing dual-lumen to multisite venovenous ECMO in the pediatric population: the Extracorporeal Life Support Registry experience

PURPOSE

The purpose of this study is to evaluate outcomes associated with single site dual-lumen venovenous cannulas (VVDL) and to compare them to those associated with multisite VV ECMO (VVMS) cannulation.

METHODS

The Extracorporeal Life Support (ELSO) Registry was reviewed to identify all children 31days to 18years treated with venovenous ECMO from 1998 to 2011 using either VVDL or VVMS techniques. Patient demographics, cannula type, ECMO variables, complications, and patient survival were analyzed.

RESULTS

From 1998 to 2011, 1323 children underwent venovenous ECMO. The annual utilization of VVDL cannulas has increased and recently surpassed VVMS. Fifty-four percent (n=717) of patients had VVDL cannulation. This group was significantly younger and weighed less than the VVMS group. VVDL cannulas demonstrated improved weight-adjusted flow performance than traditional cannulation. Overall survival was comparable, 64.4% and 68.6%, for VVMS and VVDL respectively. VVDL cannulas experienced higher mechanical (26.2% vs. 22.5%; p=0.004) and cardiovascular complications rates (24.4% vs. 21.7%; p=0.03) than VVMS cannulas, but when stratified by VVDL cannula type, there were no differences between wire-reinforced and non-wire reinforced cannulas.

CONCLUSIONS

VVDL cannulation has become the preferred modality for ECMO therapy in children with respiratory failure and it is mainly utilized in younger patients. The use of newer VVDL cannulas may provide improved pump flow performance without substantial additional risk.

Bicaval dual-lumen cannula for venovenous extracorporeal membrane oxygenation: Avalon© cannula in childhood disease

Severe acute refractory respiratory failure is considered a life-threatening situation, with a high mortality of 40 to 60%. When conservative oxygenation methods fail, a lifesaving measure is the introduction of extracorporeal membrane oxygenation (ECMO). Venovenous ECMO (VV-ECMO) is a preferred modality of support for patients with refractory acute respiratory failure. Specifically, bicaval VV-ECMO is a well-recognized and validated therapy, where single or double periphery venous access is used for the insertion of two differently sized cannulas in order to achieve adequate blood oxygenation. Compared to venoarterial ECMO, in VV-ECMO, the rate of complications, such as thrombosis, bleeding, infection and ischemic events, is lower. On the other hand, the size and insertion location is an obstacle to patient mobilization. This is a considerable problem for patients where the time interval for lung recovery and the bridge to the transplantation is prolonged. To address this issue, a dual-lumen, single venovenous cannula was introduced. Here, by insertion of one single catheter in one target vessel, in a majority of cases in the right internal jugular vein, satisfactory oxygenation of the patient is achieved. In this form, the instituted VV-ECMO enables patient mobility, better physical rehabilitation and facilitates pulmonary extubation and toilet.

However, relatively early, after the first short-term reports were published, a relatively high complication rate became evident. In the recent literature, the complication rate using actual commercially available double-lumen venovenous cannula ranges between 5 and 30%. These cases were mostly conjoined to the implantation phase or the early postoperative phase and vary between right heart perforation to migration of the cannula.

This review focuses on complications allied to commercially available dual-lumen, single, venovenous cannula implantation, pointing out the critical segments of the implantation process and analyzing the structure of the device.

Experience with the Avalon® bicaval double-lumen veno-venous cannula for neonatal respiratory ECMO

OBJECTIVE

We report a single centre experience of neonatal respiratory ECMO using the Avalon® double-lumen venous cannula and compare it with reports in the literature.

RESULTS

Between 2008 and 2012, the Avalon® cannula was used in 72 neonates: median age at cannulation was 1.8 days (IQR 1.2-2.8 days) and bodyweight 3.4 Kg (3.0-3.7 Kg). Meconium aspiration syndrome (61.1%), persistent hypertension of the newborn (25%) and congenital diaphragmatic hernia (5.6%) were the most common diagnoses. Complications occurred in 19 patients (26.4%): cannula site bleeding in 6 (8.3%), the cannula perforating the right atrial wall and requiring emergency midline sternotomy in 5 (6.9%) and the cannula needing repositioning in 3 (4.2%). Overall survival at discharge or transfer to the referring hospital was 88.8%. Successful wean off ECMO occurred in 68 patients (94.4%) after a median of 90.5 hours (63.4-136.11). ECMO support was withdrawn in 4 patients (5.6%).

CONCLUSIONS

The Avalon® dual-lumen veno-venous cannula can be used for respiratory ECMO in the neonatal population. However, as the incidence of right atrial perforation is not negligible, we suspended its used in this group of patients.

Prenatal MRI fetal lung volumes and percent liver herniation predict pulmonary morbidity in congenital diaphragmatic hernia (CDH)

PURPOSE

The purpose of this study was to determine whether prenatal imaging parameters are predictive of postnatal CDH-associated pulmonary morbidity.

METHODS

The records of all neonates with CDH treated from 2004 to 2012 were reviewed. Patients requiring supplemental oxygen at 30 days of life (DOL) were classified as having chronic lung disease (CLD). Fetal MRI-measured observed/expected total fetal lung volume (O/E-TFLV) and percent liver herniation (%LH) were recorded. Receiver operating characteristic (ROC) curves and multivariate regression were applied to assess the prognostic value of O/E-TFLV and %LH for development of CLD.

RESULTS

Of 172 neonates with CDH, 108 had fetal MRIs, and survival was 76%. 82% (89/108) were alive at DOL 30, 46 (52%) of whom had CLD. Neonates with CLD had lower mean O/E-TFLV (30 vs.42%; p=0.001) and higher %LH (21.3±2.8 vs.7.1±1.8%; p<0.001) compared to neonates without CLD. Using ROC analysis, the best cutoffs in predicting CLD were an O/E-TFLV<35% (AUC=0.74; p<0.001) and %LH>20% (AUC=0.78; p<0.001). On logistic regression, O/E-TFLV<35% and a %LH>20% were highly associated with indicators of long-term pulmonary sequelae. On multivariate analysis, %LH was the strongest predictor of CLD in patients with CDH (OR: 10.96, 95%CI: 2.5-48.9, p=0.002).

CONCLUSION

Prenatal measurement of O/E-TFLV and %LH is predictive of CDH pulmonary morbidity and can aid in establishing parental expectations of postnatal outcomes.

Venoarterial versus venovenous ECMO for neonatal respiratory failure

Extracorporeal membrane oxygenation (ECMO) continues to be an important rescue therapy for newborns with a variety of causes of cardio-respiratory failure unresponsive to high-frequency ventilation, surfactant replacement, and inhaled nitric oxide. There are approximately 800 neonatal respiratory ECMO cases reported annually to the Extracorporeal Life Support Organization; venoarterial ECMO has been used in approximately 72% with a cumulative survival of 71% and venovenous has been used in 28% with a survival of 84%. Congenital diaphragmatic hernia is now the most common indication for ECMO. This article reviews the development of the two types of extracorporeal support, venoarterial and venovenous ECMO, and discusses the advantages of each method, the current selection criteria, the procedure, and the clinical management of neonates on ECMO.

Venovenous cannulation for extracorporeal membrane oxygenation using a bicaval dual-lumen catheter in neonates

PURPOSE

Venovenous extracorporeal membrane oxygenation (VV-ECMO) has been used as a management strategy for neonates with refractory pulmonary failure. However, VV-ECMO has been limited in neonates secondary to cannula design and patient size. Herein, we describe the use of a bicaval dual-lumen catheter for VV-ECMO in neonates.

METHODS

The medical records of all neonates cannulated for ECMO support with a bicaval dual-lumen 13F catheter from 2008 to 2010 were reviewed.

RESULTS

Nine neonates cannulated with this dual-lumen catheter were identified. The median gestational age was 38 weeks (range, 31-40 weeks), the median weight was 3.4 kg (range, 2.2-5.5 kg), the median age at cannulation was 2 days (range, 1-64 days), and the median duration of ECMO support was 7 days (range, 5-23 days). There were no VV-to-VA conversions. The median pump flow both at 4 and 24 hours postcannulation was 300 mL/min (range, 240-370 mL/min). One patient developed cannula thrombosis, and one required cannula repositioning because of flow recirculation. Overall survival was 56%.

CONCLUSION

The dual-lumen bicaval catheter can be safely used in neonates with minimal complications and is our preferred method for VV-ECMO support in the neonatal population.

Comparative Study of Continuous and Pulsatile Left Ventricular Assist Devices on Hemodynamics of a Pediatric End-to-Side Anastomotic Graft

Although there are many studies that focus on understanding the consequence of pumping mode (continuous vs. pulsatile) associated with ventricular assist devices (VADs) on pediatric vascular pulsatility, the impact on local hemodynamics has been largely ignored. Hence, we compare not only the hemodynamic parameters indicative of pulsatility but also the local flow fields in the aorta and the great vessels originating from the aortic arch. A physiologic graft anastomotic model is constructed based on a pediatric, patient specific, aorta with a graft attached on the ascending aorta. The flow is simulated using a previously validated second-order accurate Navier-Stokes flow solver based upon a finite volume approach. The major findings are: (1) pulsatile support provides a greater degree of vascular pulsatility when compared to continuous support, which, however, is still 20% less than pulsatility in the healthy aorta; (2) pulsatile support increases the flow in the great vessels, while continuous support decreases it; (3) complete VAD support results in turbulence in the aorta, with maximum principal Reynolds stresses for pulsatile support and continuous support of 7081 and 249 dyn/cm2, respectively; (4) complete pulsatile support results in a significant increase in predicted hemolysis in the aorta; and (5) pulsatile support causes both higher time-averaged wall shear stresses (WSS) and oscillatory shear indices (OSI) in the aorta than does continuous support. These findings will help to identify the risk of graft failure for pediatric patients with pulsatile and continuous VADs.

CONTEMPORARY NEONATAL INTENSIVE CARE MANAGEMENT IN CONGENITAL DIAPHRAGMATIC HERNIA: DOES THIS OBVIATE THE NEED FOR FETAL THERAPY?

The management of congenital diaphragmatic hernia (CDH) in the newborn infant has changed radically since the first successful outcomes were reported 60 years ago. Then it seemed a surgical problem with a surgical solution – do an operation, remove the intestines and solid viscera from the thoracic cavity, repair the defect and allow the lung to expand. CDH in that era was regarded as the quintessential neonatal surgical emergency. The expectation was that urgent surgery would result in improvement in lung function and oxygenation. That approach persisted up to the 1980s when it was realized that the problem was far more complex and involved both an abnormal pulmonary vascular bed as well as pulmonary hypoplasia. The use of systemically delivered pulmonary vasodilator therapy, principally tolazoline, became a focus of interest in the 1980s with small case reports and case series suggesting improved survival. In the 1990s, based on studies that showed worsening thoracic compliance and gas exchange following surgical repair, deferred surgery and pre-operative stabilization became the standard of care. At the same time extracorporeal membrane oxygenation (ECMO) was increasingly used either as part of pre-operative stabilization or as a rescue therapy after repair. Other centres chose to use high frequency oscillatory ventilation (HFOV). Despite all these innovations the survival in live born infants with CDH did not improve to more than 50% in large series published from high volume centres. However, in the past 10 years there has been an appreciable improvement in survival to the extent that many centres are now reporting survival rates of greater than 80%. Probably the biggest impact on this improvement has been the recognition of the role that ventilation induced lung injury plays in mortality and the need for ECMO rescue. This has ushered in an era of a lung protective or “gentle ventilation” strategy which has been widely adopted as a standard approach. While there have been these radical changes in postnatal management attempts have been made to improve outcome with prenatal interventions, starting with prenatal repair, which was abandoned because of preterm labour. More recently there has been increasing experience in the use of balloon occlusion of the trachea as a prenatal intervention strategy with patients being selected based on prenatal predictors of poor outcome. This approach can only be justified if those predictors can be validated and the outcomes (death or serious long term morbidity) can be shown to be better than those currently achievable, namely 80% survival in high volume CDH centres rather than the 50–60% survival frequently quoted in historical papers.

Outcome analysis of neonates with congenital diaphragmatic hernia treated with venovenous vs venoarterial extracorporeal membrane oxygenation

PURPOSE

Venoarterial extracorporeal membrane oxygenation (ECMO) (VA) is used more commonly in neonates with congenital diaphragmatic hernia (CDH) than venovenous ECMO (VV). We hypothesized that VV may result in comparable outcomes in infants with CDH requiring ECMO.

METHODS

We retrospectively analyzed the Extracorporeal Life Support Organization (ELSO) database (1991-2006). Multivariate logistic regression analyses were used to compare VV- and VA-associated mortality.

RESULTS

Four thousand one hundred fifteen neonates required ECMO, with an overall mortality rate of 49.6%. Venoarterial ECMO was used in 82% and VV in 18% of neonates. Pre-ECMO inotrope use and complications were equivalent between VA and VV. The mortality rate for VA and VV was 50% and 46%, respectively. After adjusting for birth weight, gestational age, prenatal diagnosis, ethnicity, Apgar scores, pH less than 7.20, Paco(2) greater than 50, requiring high-frequency ventilation, and year of ECMO, there was no difference in mortality between VV vs VA. Renal complications and on-ECMO inotrope use were more common with VV, whereas neurologic complications were more common with VA. The conversion rate from VV to VA was 18%; conversion was associated with a 56% mortality rate.

CONCLUSION

The short-term outcomes of VV and VA are comparable. Patients with CDH who fail VV may be predisposed to a worse outcome. Nevertheless, VV offers equal benefit to patients with CDH requiring ECMO while preserving the native carotid.

Effect of Continuous and Pulsatile Flow Left Ventricular Assist on Pulsatility in a Pediatric Animal Model of Left Ventricular Dysfunction: Pilot Observations

Pediatric ventricular assist devices are being developed that can produce pulsatile flow (PF) or continuous flow (CF). An important aspect of choosing between these two modes is understanding the consequences of each mode on pediatric vascular pulsatility. Differences in vascular pulsatility generated by PF and CF operation of the 3-inch pediatric cardiopulmonary assist system (pCAS, Ension, Inc., Pittsburgh, PA) were investigated while providing left atrium-to-aorta left ventricular assist (LVA), using an infant animal model of left ventricular dysfunction. Hemodynamic data were digitally recorded with the pCAS providing LVA at incremental flow rates while operating in continuous mode, pulsatile mode at 100 bpm, and pulsatile mode at 140 bpm. These data were used to calculate vascular input impedance (Zart), energy equivalent pressure, and surplus hemodynamic energy as indices of pulsatility for partial (50% of maximum) and maximum LVA flow. Both CF and PF LVA by the pCAS resulted in favorable hemodynamic rectification of left ventricular dysfunction while generating equivalent flows. PF LVA maintained a greater degree of pulsatility compared with CF, as evidenced by increasing energy equivalent pressure and a lesser drop in surplus hemodynamic energy with increasing pCAS flow. Differences in Zart modulus and phase were indiscernible. The selection of flow mode may have long-term consequences on Zart and end-organ perfusion affecting clinical outcomes in pediatric patients.

The role of extracorporeal membrane oxygenation in the management of infants with congenital diaphragmatic hernia

Many infants with CDH can be managed with conventional mechanical ventilation and pharmacotherapy. However, some infants will require levels of ventilator support that are not compatible with survival. In these circumstances, extracorporeal membrane oxygenation (ECMO) has been used with varying results. The indication, type, and timing of ECMO in relation to surgery continue to evolve in an attempt to improve the outcome. At the same time, there is growing body of literature showing adverse outcomes among infants with CDH treated with ECMO, raising questions about the usefulness of ECMO in CDH. This paper reviews some of the controversies associated with the use of ECMO in CDH.

The use of extracorporeal membrane oxygenation in infants with congenital diaphragmatic hernia

The use of extracorporeal membrane oxygenation (ECMO) has revolutionized the care of the critical infant born with a congenital diaphragmatic hernia (CDH). In some respects, this is surprising given our current lack of understanding regarding optimal preoperative ventilation strategy, identification of patients most likely to benefit from ECMO, and the correct timing of hernia repair for the infant treated with ECMO. Historically, repair of CDH was considered one of the few true pediatric surgical emergencies. Mortality, however, was high. In the 1970s, ECMO was first utilized as a rescue therapy following repair of CDH when conventional methods failed. In the 1980s, advancements in neonatal intensive care and an understanding of the pathophysiology of pulmonary hypertension associated with CDH led to a strategy involving preoperative stabilization and delayed surgical intervention. Historical reviews demonstrate an improvement of survival in infants treated with ECMO from 56% to 71%. This paper will outline the advances in the care of the CDH patient and the approach used for treatment with ECMO.

Venovenous extracorporeal membrane oxygenation in neonatal respiratory failure: does routine, cephalad jugular drainage improve outcome?

BACKGROUND/PURPOSE

Extracorporeal membrane oxygenation (ECMO), may be life saving for infants with severe respiratory failure, and when possible, veno-venous bypass through a jugular double lumen cannula, can be expected to provide satisfactory support for most patients. Some ECMO centers favor routine placement of a cephalad jugular cannula for the theoretical benefits of augmented (desaturated) venous return, reduction of atrial recirculation, and cerebral venous decompression. The purpose of this study was to querie the ELSO registry for patients who had undergone VV-ECMO and compare outcomes for patients with a double lumen cannula only (VVDL), with those who had both a double lumen and cephalad jugular cannula (VVDL + V).

METHODS

With institutional review board (IRB) approval, the Extracorporeal Life Support Organization (ELSO) registry (Ann Arbor, MI) was queried from January 1, 1989 to December 31, 2001, and all "neonatal respiratory" patients undergoing VV-ECMO via either the VVDL or VVDL + V modes were identified. Group comparisons by age, diagnosis, hours on bypass, mean flow rates (Q) at 4 and 24 hours, mean airway pressures (MAP) at initiation and at 24 hours of bypass, complications (including neurologic and cannula-specific), need for conversion to veno-arterial (VA) ECMO, and survival were performed. A similar analysis was performed on a congenital diaphragmatic hernia (CDH) patient subgroup. Student's t tests were used to compare means between groups, with P values of less than.05 considered significant.

RESULTS

The querie generated a total of 2,471 patients: 2,379 (96.3%) VVDL, and 92 (3.7%) VVDL + V. The groups were comparable with the only significant differences being a higher mean airway pressure at 24 hours of bypass and a more frequent use of inotropes during extracorporeal life support (ECLS) in the VVDL + V group. Comparison of a CDH patient subset (280 from the VVDL group and 25 from the VVDL + V group) showed the following significant differences: more frequent use of inotropes, higher MAP at 24 hours, and higher mean flow rates at 4 and 24 hours, all in the VVDL + V group. Patient outcomes, including survival, complications, and rates of conversion to VA bypass were comparable between like groups.

CONCLUSIONS

The theoretical benefits of routine placement of a cephalad jugular cannula during VV-ECMO via a jugular double lumen cannula are not substantiated by critical analysis of ELSO data.

Venovenous versus venoarterial extracorporeal membrane oxygenation in congenital diaphragmatic hernia

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has a significant role as a final rescue modality in severe respiratory failure of the newborn with congenital diaphragmatic hernia (CDH). The objective of this study was to compare the efficiency of venovenous (VV) versus venoarterial (VA) ECMO in newborns with CDH.

METHODS

A retrospective report of 11 years experience (1990 through 2001) of a single center, comparing VV and VA ECMO is given. VV ECMO was the preferred rescue modality for respiratory failure unresponsive to maximal medical therapy. Only when the placement of a VV ECMO 14F catheter was not possible, VA ECMO was used. Forty-six patients met ECMO criteria; 26 were treated with VV ECMO and 19 with VA ECMO. One patient underwent conversion from VV to VA ECMO.

RESULTS

Before ECMO, there was no difference between VV and VA ECMO patients in mean oxygenation index (83 v 83), mean airway pressure (18.4 v 18.9 cm H(2)O), ECMO cannulation age (28 v 20 hours), or in the percentage of patients who needed dopamine and dobutamine (100% v 100%). From November 1994, nitric oxide (NO) was available; before ECMO, 11 of 14 (79%) VV ECMO patients received NO versus 9 of 10 (90%) patients in the VA group. VV ECMO patients were larger (3.34 v 2.77 kg; P <.05) and of advanced gestational age (39.0 v 36.9 wk; P <.05) compared with VA ECMO patients. There was no significant difference between VV and VA ECMO patients in survival rate (18 of 26, 69% v 13 of 19, 68%), ECMO duration (152 v 150 hours), time of extubation (32.0 v 33.5 days), age at discharge (73 v 81 days), or incidence of short-term intracranial complications (3.8% v 10.5%) or myocardial stun (3.8% v 15.8%).

CONCLUSIONS

The authors conclude that VV ECMO is as reliable as VA ECMO in newborns with CDH in severe respiratory failure who need ECMO support and who can accommodate the VV double-lumen catheter. Because of its potential advantages, VV ECMO may be the preferred ECMO method in these infants.

New trends in extracorporeal membrane oxygenation in newborn pulmonary diseases

New trends in extracorporeal membrane oxygenation (ECMO) for respiratory failure in the newborn were reviewed. Following a decade of clinical research, ECMO is now the standard treatment for newborn respiratory failure when all other conventional less-invasive treatment options have been exhausted. As of July 2000, 15,525 newborns with respiratory failure treated with ECMO have been entered into the registry of the Extracorporeal Life Support Organization with an overall survival rate of 78%. The latest improvement in ECMO technology in this group of patients includes minimally invasive modes of vascular access through percutaneous approaches to minimize morbidity. However, with advances in modes of mechanical ventilation, including high-frequency ventilation and the introduction of inhaled nitric oxide, the use and necessity for ECMO have clearly diminished for newborn respiratory failure.

Venoarterial versus venovenous extracorporeal membrane oxygenation in congenital diaphragmatic hernia: the Extracorporeal Life Support Organization Registry, 1990-1999

BACKGROUND/PURPOSE

Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) traditionally has been the mode of support used in congenital diaphragmatic hernia (CDH). A few studies report success using venovenous (VV) ECMO. The purpose of this study is to compare outcomes in CDH patients treated with VA and VV.

METHODS

The authors queried the Extracorporeal Life Support Organization Registry for newborns with CDH treated with ECMO from January 1, 1990 through December 31, 1999. They analyzed the pre-ECMO data, ECMO course, and complications.

RESULTS

VA was utilized in 2,257 (86%) and VV in 371 (14%) patients. The pre-ECMO status was similar, with greater use of nitric oxide, surfactant, and pressors in VV. Survival rate was similar (58.4% for VV and 52.2% for VA, P =.057). VA was associated with more seizures (12.3% v 6.7%, P =.0024) and cerebral infarction (10.5% v 6.7%, P =.03). Sixty-four treatments were converted from VV to VA (VV-->VA). Survival rate in VV-->VA was not significantly different than VA (43.8% v 52.2%, respectively; P =.23). VV-->VA and VA patients had similar neurologic complications.

CONCLUSIONS

CDH patients treated with VV and VA have similar survival rates. VA had more neurologic complications. The authors identified no disadvantage to the use of VV as an initial mode of ECMO for CDH, although some infants may need conversion to VA.

The Edmonton experience with venovenous extracorporeal membrane oxygenation

BACKGROUND/PURPOSE

Despite the proven effectiveness of venovenous extracorporeal membrane oxygenation (VV ECMO) in the treatment of neonates with severe respiratory failure, this technique is not widely used. The purpose of this study was to assess the authors' policy of preferred use of VV ECMO with a cephalad catheter and to compare the results with those of the Extracorporeal Life Support Organization (ELSO) Registry.

METHODS

Charts of neonatal ECMO candidates were reviewed retrospectively. Data were collected for gestational age, birth weight, and diagnosis. Severity of illness was assessed by oxygenation index, lactate levels, and inotropic requirements before cannulation. Patients were divided into three groups: venovenous (VV), venoarterial (VA), and VV to VA ECMO. A cephalad catheter was inserted in the distal part of the jugular vein.

RESULTS

Sixty-five neonates were supported with ECMO. Cannulation with a double lumen venovenous (VVDL) catheter was attempted in 63 neonates and successfully accomplished in 57. A survival rate of 86% was observed in neonates initially placed on VV ECMO. Five neonates initially placed on VV ECMO underwent conversion to VA ECMO.

CONCLUSIONS

This study showed that the authors' preferred policy of VV ECMO did not result in an increase in mortality rate based on a comparison with ELSO data. VV ECMO with a cephalad catheter provides adequate support for unstable neonates with respiratory failure.