Venovenous ECMO for Congenital Diaphragmatic Hernia: Role of Ductal Patency and Lung Recruitment

Ductus Arteriosus Patency for the Hemodynamic Management of Newborns With Pulmonary Hypertension on Veno-Venous Extracorporeal Membrane Oxygenation

In neonates with pulmonary hypertension (PH) supported on veno-venous extracorporeal membrane oxygenation (VV-ECMO), keeping the ductus arteriosus (DA) open ensures a high cardiac output of well-oxygenated blood through the right to left (R-L) ductal shunt. After PH resolution, timely closure of the patent DA (PDA) prevents pulmonary overcirculation, systemic hypoperfusion, and unsuccessful ECMO weaning. We retrospectively evaluated its impact on the echocardiographic and hemodynamic features of 18 newborns undergoing VV-ECMO because of acute hypoxic respiratory failure in PH. At ECMO start, PDA was left or maintained open for all patients with echocardiographic signs of PH. After ECMO initiation, PDA shunt reverted into left to right (L-R). Twenty-four hours before DA closure, the echocardiographic assessment suggested a drop in pulmonary vascular resistances (PVRs). At 24 and 48 hours after DA closure, cardiac ultrasound confirmed continued improvement of PH. Ductus arteriosus closure is associated with a significant drop in arterial lactates (p = 0.014) and increase in diastolic blood pressure (p = 0.037). All patients, except for the two who died on ECMO, were successfully weaned from extracorporeal life support. Overall survival was 61.1%. These preliminary data suggest the feasibility and safety of DA patency manipulation in neonates undergoing VV-ECMO for PH, supporting a VV configuration in this patient population.

Could a Two-Staged Repair Be the Solution to the Dilemma of Repair Timing for Severe Congenital Diaphragmatic Hernia Requiring Extracorporeal Membrane Oxygenation?

PURPOSE OF REVIEW

Congenital diaphragmatic hernia (CDH) remains a significant challenge, particularly in severe cases with persistent pulmonary hypertension (PPHN) and hypoplastic lungs and heart. For patients unresponsive to conventional therapies, ECMO is required. While the surgical repair is relatively simple, determining the optimal timing for surgery in patients requiring ECMO is particularly challenging. This review explores the dilemma of surgical timing and proposes a two-staged approach: a reduction in herniated organs and the creation of a silo to relieve abdominal pressure before initiating ECMO, with defect closure following ECMO decannulation.

RECENT FINDINGS

Studies support pre-, on-, and post-ECMO repair, each with its own risks and benefits. Pre-ECMO repair may enhance ECMO efficacy by relieving organ compression but poses risks due to instability. Post-ECMO repair is safer but may result in losing the chance to repair. On-ECMO repair has significant hemorrhage risks, but early repair with careful anticoagulation management is currently recommended. Recently, the author reported a successful case using a two-staged approach-reducing herniated organs and creating a silo before ECMO, followed by defect closure after ECMO decannulation-which suggests a potential alternative strategy for managing severe CDH.

SUMMARY

A two-staged approach may offer a solution for severe CDH patients requiring ECMO.

International treatment outcomes of neonates on extracorporeal membrane oxygenation (ECMO) with persistent pulmonary hypertension of the newborn (PPHN): a systematic review

BACKGROUND

PPHN is a common cause of neonatal respiratory failure and is still a serious condition and associated with high mortality.

OBJECTIVES

To compare the demographic variables, clinical characteristics, and treatment outcomes in neonates with PHHN who underwent ECMO and survived compared to neonates with PHHN who underwent ECMO and died.

METHODS

We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and searched ProQuest, Medline, Embase, PubMed, CINAHL, Wiley online library, Scopus and Nature for studies on the development of PPHN in neonates who underwent ECMO, published from January 1, 2010 to May 31, 2023, with English language restriction.

RESULTS

Of the 5689 papers that were identified, 134 articles were included in the systematic review. Studies involving 1814 neonates with PPHN who were placed on ECMO were analyzed (1218 survived and 594 died). Neonates in the PPHN group who died had lower proportion of normal spontaneous vaginal delivery (6.4% vs 1.8%; p value > 0.05) and lower Apgar scores at 1 min and 5 min [i.e., low Apgar score: 1.5% vs 0.5%, moderately abnormal Apgar score: 10.3% vs 1.2% and reassuring Apgar score: 4% vs 2.3%; p value = 0.039] compared to those who survived. Neonates who had PPHN and died had higher proportion of medical comorbidities such as omphalocele (0.7% vs 4.7%), systemic hypotension (1% vs 2.5%), infection with Herpes simplex virus (0.4% vs 2.2%) or Bordetella pertussis (0.7% vs 2%); p = 0.042. Neonates with PPHN in the death group were more likely to present due to congenital diaphragmatic hernia (25.5% vs 47.3%), neonatal respiratory distress syndrome (4.2% vs 13.5%), meconium aspiration syndrome (8% vs 12.1%), pneumonia (1.6% vs 8.4%), sepsis (1.5% vs 8.2%) and alveolar capillary dysplasia with misalignment of pulmonary veins (0.1% vs 4.4%); p = 0.019. Neonates with PPHN who died needed a longer median time of mechanical ventilation (15 days, IQR 10 to 27 vs. 10 days, IQR 7 to 28; p = 0.024) and ECMO use (9.2 days, IQR 3.9 to 13.5 vs. 6 days, IQR 3 to 12.5; p = 0.033), and a shorter median duration of hospital stay (23 days, IQR 12.5 to 46 vs. 58.5 days, IQR 28.2 to 60.7; p = 0.000) compared to the neonates with PPHN who survived. ECMO-related complications such as chylothorax (1% vs 2.7%), intracranial bleeding (1.2% vs 1.7%) and catheter-related infections (0% vs 0.3%) were more frequent in the group of neonates with PPHN who died (p = 0.031).

CONCLUSION

ECMO in the neonates with PPHN who failed supportive cardiorespiratory care and conventional therapies has been successfully utilized with a neonatal survival rate of 67.1%. Mortality in neonates with PPHN who underwent ECMO was highest in cases born via the caesarean delivery mode or neonates who had lower Apgar scores at birth. Fatality rate in neonates with PPHN who underwent ECMO was the highest in patients with higher rate of specific medical comorbidities (omphalocele, systemic hypotension and infection with Herpes simplex virus or Bordetella pertussis) or cases who had PPHN due to higher rate of specific etiologies (congenital diaphragmatic hernia, neonatal respiratory distress syndrome and meconium aspiration syndrome). Neonates with PPHN who died may need a longer time of mechanical ventilation and ECMO use and a shorter duration of hospital stay; and may experience higher frequency of ECMO-related complications (chylothorax, intracranial bleeding and catheter-related infections) in comparison with the neonates with PPHN who survived.

Use of point-of-care ultrasound (POCUS) to monitor neonatal and pediatric extracorporeal life support

Extracorporeal membrane oxygenation (ECMO) is an invasive life support technique that requires a blood pump, an artificial membrane lung, and vascular cannulae to drain de-oxygenated blood, remove carbon dioxide, oxygenate, and return it to the patient. ECMO is generally used to provide advanced and prolonged cardiopulmonary support in patients with refractory acute cardiac and/or respiratory failure. After its first use in 1975 to manage a severe form of meconium aspiration syndrome with resultant pulmonary hypertension, the following years were dominated by the use of ECMO to manage neonatal respiratory failure and limited to a few centers across the world. In the 1990s, evidence for neonatal respiratory ECMO support increased; however, the number of cases began to decline with the use of newer pharmacologic therapies (e.g., inhaled nitric oxide, exogenous surfactant, and high-frequency oscillatory ventilation). On the contrary, pediatric ECMO sustained steady growth. Combined advances in ECMO technology and bedside medical management have improved general outcomes, although ECMO-related complications remain challenging. Point-of-care ultrasound (POCUS) is an essential tool to monitor all phases of neonatal and pediatric ECMO: evaluation of ECMO candidacy, ultrasound-guided ECMO cannulation, daily evaluation of heart and lung function and brain perfusion, detection and management of major complications, and weaning from ECMO support.  Conclusion: Based on these considerations and on the lack of specific guidelines for the use of POCUS in the neonatal and pediatric ECMO setting, the aim of this paper is to provide a systematic overview for the application of POCUS during ECMO support in these populations. What is Known: • Extracorporeal membrane oxygenation (ECMO) provides advanced cardiopulmonary support for patients with refractory acute cardiac and/or respiratory failure and requires appropriate monitoring. • Point-of-care ultrasound (POCUS) is an accessible and adaptable tool to assess neonatal and pediatric cardiac and/or respiratory failure at bedside. What is New: • In this review, we discussed the use of POCUS to monitor and manage at bedside neonatal and pediatric patients supported with ECMO. • We explored the potential use of POCUS during all phases of ECMO support: pre-ECMO assessment, ECMO candidacy evaluation, daily evaluation of heart, lung and brain function, detection and troubleshooting of major complications, and weaning from ECMO support.

Management of the CDH patient on ECLS

Congenital diaphragmatic hernia (CDH) is the most common indication for respiratory extracorporeal life support (ECLS) in neonates. The survival rate of CDH neonates treated with ECLS is 50%, and this figure has remained relatively stable over the last few decades. This is likely because the current population of CDH neonates who require ECLS have a higher risk profile [1]. The management of neonates with CDH has evolved over time to emphasize postnatal stabilization, gentle ventilation, and multi-modal treatment of pulmonary hypertension. In order to minimize practice variation, many centers have adopted CDH-specific clinical practice guidelines, however care is not standardized between different centers and outcomes vary [3]. The purpose of this review is to summarize our current understanding of issues central to the care of neonates with CDH treated with ECLS and specifically highlight how the use of the Extracorporeal Life Support Organization (ELSO) data have added to our understanding of CDH.

Prostaglandin E1 in infants with congenital diaphragmatic hernia (CDH) and life-threatening pulmonary hypertension

BACKGROUND

Suprasystemic pulmonary hypertension (PH) is highly predictive of pulmonary morbidity and death in infants with congenital diaphragmatic hernia (CDH).

OBJECTIVES

To report the effects and tolerability of Prostaglandin E₁ (PGE₁) in newborns with severe CDH and life-threatening PH.

METHODS

Newborn infants with isolated CDH and life-threatening PH defined by an acute worsening of the cardiorespiratory function, and bidirectional or exclusive right-to-left shunting across the ductus arteriosus (DA) with an acceleration of the blood flow >1.5 m.s^-1 assessed by Doppler echocardiography. Serial measurements of cardiorespiratory variables have been recorded before and after PGE₁.

RESULTS

18 infants (out of 102 in the cohort) were included in the study (gestational age: 39 ± 2 weeks). The median FiO₂, and preductal and postductal SpO₂ were 80% [50; 100], 91% [88; 95] and 86% [82; 91], respectively, before treatment. FiO₂ decreased to 35% [30-40] (p = 0.001) at H6. Maximal blood flow velocities in the DA decreased after starting PGE₁ from 2.2 m.s^-1 [1.5-2.5] to 1 m.s^-1 [0.55-1.2] (p < 0.001).

CONCLUSIONS

PGE₁ treatment improved oxygenation and circulatory function in newborn infants with severe CDH and life-threatening PH. Our data provide evidence that restrictive DA may result in suprasystemic pulmonary hypertension in CDH infants, and that PGE₁ may improve cardiorespiratory failure through reopening of the DA.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

Level III.

Intensivists Performed Percutaneous Bicaval Double-Lumen Echo-Guided Extracorporeal Membrane Oxygenation Cannulation at Bedside in Newborns and Children: A Retrospective Analysis

OBJECTIVES

To describe a single institution experience on echo-guided percutaneous bicaval double lumen extracorporeal membrane oxygenation cannulation performed at the bedside by intensivists.

DESIGN

Retrospective observational study.

SETTING

Extracorporeal membrane oxygenation team of a tertiary care children's hospital.

PATIENTS

All patients 0-14 years old undergoing venovenous extracorporeal membrane oxygenation from January 1, 2013, to January 1, 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Thirty children underwent 32 extracorporeal membrane oxygenation runs. Median age at enrollment was 2 months (interquartile range, 0-20.5 mo), 65.6% of the runs (21 patients) were performed in newborns (n = 13, 40.6%) or infants (n = 8, 25%). Median preextracorporeal membrane oxygenation index was 66.9 (interquartile range, 50-85.6). Major comorbidities were present in 50% of patients. All patients were cannulated percutaneously. In two cases cannulation occurred from the left internal jugular vein. Extracorporeal membrane oxygenation was effective in increasing pH, arterial oxygen saturation, PaO2, and lowering PaCO2. The overall differences in pre and postextracorporeal membrane oxygenation values were statistically significant, while stratifying patients according to the cannula diameter (mm)/major diameter of the cannulated internal jugular vein (mm) ratio (> 0.67 or ≤ 0.67), statistical significance was reached only for the highest ratio. Complications were observed in three runs: two cannula tip dislocations in the right atrium and one limited flow in the only case in which an Avalon cannula was not used. In 20 cases (62.5% of 32 runs), the cannulated vessel was patent at follow-up or autopsy. A ratio less than or equal to 0.67 or greater than 0.67 did not influence the occurrence rate of complications, nonpatency of the internal jugular vein, death for intracranial bleeding and death at 30 days from extracorporeal membrane oxygenation discontinuation. Overall cumulative survival at 30 days from extracorporeal membrane oxygenation discontinuation was 60% (95% CI, 40-75), with a survival advantage in the case of ratio greater than 0.67 (65%; 95% CI, 44-80 vs 25%; 95% CI, 0-60).

CONCLUSIONS

The described technique proved to be feasible, safe, and effective. Further investigation is needed.

Pertussis vaccination in pregnancy: how many pediatric hospitalizations could be prevented?

Pertussis is a severe disease in children, especially in neonates and it is preventable by vaccination during pregnancy. After the observation of a 2-month-old toddler who needed extracorporeal membrane oxygenation for severe RSV plus Bordetella pertussis infection, we performed a review of all cases of pertussis admitted at the Istituto Giannina Gaslini, Genoa, Italy, from 2012 to 2018. We retrieved 72 cases of admission for pertussis, 46% aging less than 3 months, 42% with at least one comorbidity. Two patients needed ICU admission. Pertussis vaccination during pregnancy could contribute to reduce this burden of hospitalizations in youngest subjects.

Use of prostaglandin E1 to treat pulmonary hypertension in congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Prostaglandin E1 (PGE) has been used to maintain ductus arteriosus patency and unload the suprasystemic right ventricle (RV) in neonates with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension (PH). Here we evaluate the PH response in neonates with CDH and severe PH treated with PGE.

METHODS

We performed a retrospective chart review of CDH infants treated at our center between 2011 and 2016. In a subset, PGE was initiated for echocardiographic evidence of severe PH, metabolic acidosis, or hypoxemia. To assess PH response, we evaluated laboratory data, including B-type natriuretic peptide (BNP) and echocardiograms before and after PGE treatment. Categorical and continuous data were analyzed with Fisher's exact tests and Mann-Whitney t-tests, respectively.

RESULTS

Fifty-seven infants were treated with PGE a mean 17 ± 2 days. BNP levels declined after 1.4 ± 0.2 days of treatment and again after 5.2 ± 0.6 days. After 6 ± 0.8 days of treatment, echocardiographic estimates of severe PH by tricuspid regurgitation jet velocity, ductus arteriosus direction, and ventricular septum position also improved significantly. Treatment was not associated with postductal hypoxemia or systemic hypoperfusion.

CONCLUSIONS

In patients with CDH and severe PH, PGE is well tolerated and associated with improved BNP and echocardiographic indices of PH, suggesting successful unloading of the RV.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

Level III.

The Sublingual Microcirculation Throughout Neonatal and Pediatric Extracorporeal Membrane Oxygenation Treatment: Is It Altered by Systemic Extracorporeal Support?

Background: Extracorporeal membrane oxygenation (ECMO) treatment alleviates systemic cardiorespiratory failure. However, it is unclear whether ECMO also improves microcirculatory function, as the microcirculation can be disturbed despite normal systemic hemodynamics. We therefore aimed to study the sublingual microcirculation (SMC) throughout neonatal and pediatric ECMO treatment. We hypothesized that the SMC improves after starting ECMO, that the SMC differs between venovenous (VV) and venoarterial (VA) ECMO, and that insufficient recovery of microcirculatory disturbances during ECMO predicts mortality. Methods: This single-center prospective longitudinal observational study included 34 consecutive children (April 2016-September 2018). The SMC was assessed daily with a handheld vital microscope (integrated with incident dark field illumination) before, during, and after ECMO. Validated parameters of vessel density, perfusion, and flow quality were assessed for all vessels (diameter <100 μm) and small vessels (<20 μm). Linear mixed models and logistic regression models were built to assess changes over time and identify significant covariates. Using ROC curves, the predictive values of microcirculatory parameters were assessed for mortality on ECMO and overall mortality. Results: The study population comprised 34 patients (median age 0.27 years, 16 neonates, 16 females). Twelve patients were treated with VV and 22 with VA ECMO. Twelve patients died during ECMO (stopped due to futility) and 3 died after ECMO but before discharge. Microcirculatory parameters did not change significantly before, during or after ECMO. Except between microcirculatory flow index (MFI) and mean arterial pressure (MAP), no significant associations were found between microcirculatory parameters and global systemic hemodynamics. The probability of an undisturbed MFI (>2.6) increased with higher MAP (OR: 1.050, 95%CI: 1.008-1.094). Microcirculatory parameters did not significantly differ between VV and VA ECMO or between survivors and non-survivors. None of the microcirculatory parameters could predict mortality on ECMO or overall mortality. Conclusion: In this heterogeneous study population, we were not able to demonstrate an effect of ECMO on the sublingual microcirculation. Microcirculatory parameters did not change throughout ECMO treatment and did not differ between VV and VA ECMO or between survivors and non-survivors. Future research should focus on determining which neonatal and pediatric ECMO patients would benefit from microcirculatory monitoring and how.

Patent ductus arteriosus: The physiology of transition

The transition from intrauterine to extrauterine life represents a critical phase of physiological adaptation which impacts many organ systems, most notably the heart and the lungs. The majority of term neonates complete this transition without complications; however, dysregulation of normal postnatal adaptation may lead to acute cardiopulmonary instability, necessitating advanced intensive care support. Although not as well appreciated as changes in vascular resistances, the shunt across the DA plays a crucial physiologic role in the adaptive processes related to normal transitional circulation. Further, we describe key differences in the behavior of the ductal shunt during transition in preterm neonates and we postulate mechanisms through which the DA may modulate major hemodynamic complications during this vulnerable period. Finally, we describe the conditions in which preservation of ductal patency is a desired clinical goal and we discuss clinical factors that may determine adequate balance between pulmonary and systemic circulation.

Variable role of patent ductus arteriosus

Although patent ductus arteriosus is essential in fetal life, interventions to close or minimize the adverse hemodynamic effects associated with the left-to-right shunt are often needed after birth, especially in extremely premature infants. However, there are clinical conditions where maintaining patency of the ductus is essential for survival. In this article we discuss use of prostaglandin E₁ in the management of congenital heart defects, pulmonary hypertension and left ventricular failure in early neonatal period.