Extracorporeal membrane oxygenation in infants with meconium aspiration syndrome: a decade of experience with venovenous ECMO

Morbidity of conversion from venovenous to venoarterial ECMO in neonates with meconium aspiration or persistent pulmonary hypertension

BACKGROUND

Outcomes in neonates receiving extracorporeal membrane oxygenation (ECMO) for meconium aspiration syndrome (MAS) and/or persistent pulmonary hypertension (PPHN) are favorable. Infants with preserved perfusion are often offered venovenous (VV) support to spare morbidities of venoarterial (VA) ECMO. Worsening perfusion or circuit complications can prompt conversion from VV-to-VA support. We examined whether outcomes in infants requiring VA ECMO for MAS/PPHN differed if they underwent VA support initially versus converting to VA after a VV trial, and what factors predicted conversion.

METHODS

We reviewed the Extracorporeal Life Support Organization registry from 2007 to 2017 for neonates with primary diagnoses of MAS/PPHN. Propensity score analysis matched VA single-runs (controls) 4:1 against VV-to-VA conversions based on age, pre-ECMO pH, and precannulation arrests. Primary outcomes were complications and survival. Data were analyzed using Mann-Whitney U and Fisher's exact testing. Multivariate regression identified independent predictors of conversion for VV patients.

RESULTS

3831 neonates underwent ECMO for MAS/PPHN, including 2129 (55%) initially requiring VA support. Of 1702 patients placed on VV ECMO, 98 (5.8%) required VV-to-VA conversion. Compared with 364 propensity-matched isolated VA controls, conversion runs were longer (190 vs. 127 h, P < 0.001), were associated with more complications, and decreased survival to discharge (70% vs. 83%, P = 0.01). On multivariate regression, conversion was more likely if neonates on VV ECMO did not receive surfactant (OR = 1.7;95%CI = 1.1-2.7;P = 0.03) or required high-frequency ventilation (OR = 1.9;95%CI = 1.2-3.3;P = 0.01) before ECMO.

CONCLUSION

Conversion from VV-to-VA ECMO in infants with MAS/PPHN conveys increased morbidity and mortality compared to similar patients placed initially onto VA ECMO. VV patients not receiving surfactant or requiring high-frequency ventilation before cannulation may have increased risk of conversion. While conversions remain rare, decisions to offer VV ECMO for MAS/PPHN must be informed by inferior outcomes observed should conversion be required.

LEVEL OF EVIDENCE

Level of evidence 3 Retrospective comparative study.

Complications and mortality of venovenous extracorporeal membrane oxygenation in the treatment of neonatal respiratory failure: a systematic review and meta-analysis

Background

Extracorporeal membrane oxygenation (ECMO) has been increasingly used for severe neonatal respiratory failure refractory to conventional treatments. To systematically evaluate the complications and mortality of venovenous ECMO (VV ECMO) in the treatment of neonatal respiratory failure, we performed a systematic review and meta-analysis of all the related studies.

Methods

PubMed, Embase, and Cochrane Library were searched. The retrieval period was from the establishment of the database to February 2019. Two investigators independently screened articles according to the inclusion and exclusion criteria. The quality of article was assessed by the Newcastle-Ottawa scale (NOS). The meta-analysis was performed by Stata 15.0 software.

Results

Four observational studies were included, with a total of 347 newborns. VV ECMO was used for neonates with refractory respiratory failure unresponsive to maximal medical therapy. Median ages of the newborns at cannulation were 43.2 h, 23 h, 19 h, and 71 h in the included four studies, respectively. The overall mortality at hospital charge was 12% (5–18%) with a heterogeneity of I² = 73.8% (p = 0.01). Two studies reported mortality during ECMO and after decannulation, with 10% (0.8–19.2%) and 6.1% (2.6–9.6%), respectively. The most common complications associated with VV ECMO were: pneumothorax (20.6%), hypertension (20.4%), cannula dysfunction (20.2%), seizure (14.9%), renal failure requiring hemofiltration (14.7%), infectious complications (10.3%), thrombi (7.4%), intracranial hemorrhage or infarction (6.6%), hemolysis (5.3%), cannula site bleeding (4.4%), gastrointestinal bleeding (3.7%), oxygenator failure (2.8%), other bleeding events (2.8%), brain death (1.9%), and myocardial stun (0.9%).

Conclusion

The overall mortality at discharge of VV ECMO in the treatment of neonatal respiratory failure was 12%. Although complications are frequent, the survival rate during hospitalization is still high. Further larger samples, and higher quality of randomized controlled trials (RCTs) are needed to clarify the efficacy and safety of this technique in the treatment of neonatal respiratory failure.

Inotrope Needs in Neonates Requiring Extracorporeal Membrane Oxygenation for Respiratory Failure

OBJECTIVE

To evaluate how inotropic requirements in neonates with respiratory failure are affected by extracorporeal membrane oxygenation (ECMO) mode and whether high requirements predict mortality.

STUDY DESIGN

This retrospective chart review included all neonates undergoing ECMO for primary respiratory failure from 2010 to 2016 at a single institution. The vasoactive inotropy score (VIS) was calculated as described in the literature. Data were analyzed with descriptive statistics and univariate analyses.

RESULTS

Of the 110 identified neonates, 96 underwent venovenous (VV) (87%), 11 (10%) venoarterial, and 3 (3%) converted from VV to venoarterial. The median precannulation VIS score was 33.02 for patients who underwent VV compared with 28.93 for venoarterial (P = .25) and 15 for infants converted. VIS decreased dramatically by 4 hours of ECMO in both groups. The VIS before cannulation was similar in survivors and nonsurvivors, but was significantly higher in nonsurvivors after 24 hours of ECMO (median VIS, 12 [IQR, 8-25] vs 8 [IQR, 3.0-14.5]; P = .035) and at decannulation (10 [IQR, 7-19] vs 3 [IQR, 0-7]; P < .001).

CONCLUSIONS

Neonates with respiratory failure can be successfully managed on VV ECMO even with considerable vasoactive requirements. Vasoactive requirement after 24 hours of ECMO was predictive of mortality.

Use of venovenous ECMO for neonatal and pediatric ECMO: a decade of experience at a tertiary children's hospital

BACKGROUND

Advances in extracorporeal membrane oxygenation (ECMO) have led to increased use of venovenous (VV) ECMO in the pediatric population. We present the evolution and experience of pediatric VV ECMO at a tertiary care institution.

METHODS

A retrospective cohort study from 01/2005 to 07/2016 was performed, comparing by cannulation mode. Survival to discharge, complications, and decannulation analyses were performed.

RESULTS

In total, 160 patients (105 NICU, 55 PICU) required 13 ± 11 days of ECMO. VV cannulation was used primarily in 83 patients with 64% survival, while venoarterial (VA) ECMO was used in 77 patients with 54% survival. Overall, 74% of patients (n = 118) were successfully decannulated; 57% survived to discharge. VA ECMO had a higher rate of intra-cranial hemorrhage than VV (22 vs 9%, p = 0.003). Sixteen VA patients (21%) had radiographic evidence of a cerebral ischemic insult. No cardiac complications occurred with the use of dual-lumen VV cannulas. There were no differences in complications (p = 0.40) or re-operations (p = 0.85) between the VV and VA groups.

CONCLUSION

Dual-lumen VV ECMO can be safely performed with appropriate image guidance, is associated with a lower rate of intra-cranial hemorrhage, and may be the preferred first-line mode of ECMO support in appropriately selected NICU and PICU patients.

LEVEL OF EVIDENCE

II.

Current trends in neonatal ECMO

Extracorporeal membrane oxygenation (ECMO) is a life-saving therapy for patients with respiratory and cardiac failure refractory to maximal medical management. The extracorporeal life support organization registry is the largest available resource for describing the population and outcomes of patients treated with this therapy. The use of ECMO for neonatal patients is decreasing in proportion to the total annual ECMO runs most likely due to advancements in medical management. Although the overall survival for neonatal ECMO has decreased, this is likely a reflection of the increasingly complex neonatal patients treated with this therapy. Although many patient and mechanical complications are decreasing over time, there remains a high percentage of morbidities and risks associated with ECMO. Continued refinements in management strategies are important to improving overall patient outcomes.

Venoarterial Extracorporeal Life Support for Neonatal Respiratory Failure: Indications and Impact on Mortality

Venoarterial (VA) extracorporeal life support (ECLS) for neonatal respiratory failure is associated with increased mortality compared with venovenous (VV) ECLS. It is unclear whether this is a causal relationship or reflects differences in baseline disease severity between infants managed with these two strategies. Our objective was to identify clinical variables associated with the preferential selection of VA over VV ECLS, as these may confound the association between VA ECLS and increased mortality. We identified documented indications for preferential VA selection through chart review. We then assessed how the presence of common indications impacted mortality. Thirty-nine cases met eligibility. Severity of hypotension/degree of inotropic support and ventricular dysfunction on echocardiogram before cannulation were the most common specific indications for preferential VA ECLS. Mortality was 12.5% when neither high inotropic support nor ventricular dysfunction was present. Mortality rose to 20% with high inotropic support and 25% with ventricular dysfunction present alone and to 50% when both were present. We conclude that severe hypotension and ventricular dysfunction before ECLS cannulation are common indications for VA ECLS that likely influence survival. Research assessing the impact of ECLS cannulation mode on survival should adjust for baseline differences between groups for these important variables.

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.

Is age at initiation of extracorporeal life support associated with mortality and intraventricular hemorrhage in neonates with respiratory failure?

OBJECTIVE

To describe differences in characteristics among neonates treated with extracorporeal life support (ECLS) in the first week of life for respiratory failure compared with later in the neonatal period and to assess risk factors for central nervous system (CNS) hemorrhage and mortality among the two groups.

STUDY DESIGN

Review of the Extracorporeal Life Support Organization registry from 2001 to 2010 of neonates ⩽30 days comparing two age groups: those ⩽7 days (Group 1) to those >7 days (Group 2) at ECLS initiation.

RESULT

Among 4888 neonates, Group 1 (n=4453) had significantly lower mortality (17 vs 39%, P<0.001) but greater CNS hemorrhage (11 vs 7%, P=0.02) than Group 2 (n=453). Mortality and CNS hemorrhage improved significantly with increasing gestational age only for Group 1 patients. CNS hemorrhage occurred more frequently in Group 1 patients receiving venoarterial (VA) than with venovenous ECLS (15 vs 7%, P<0.001). In Group 1, lower birth weight and pre-ECLS pH and VA mode were independently associated with mortality. In Group 2, higher mean airway pressure was independently associated with mortality. Complications of ECLS therapy, including CNS hemorrhage and renal replacement therapy were independently associated with mortality for both groups.

CONCLUSION

Neonates cannulated for ECLS after the first week of life had greater mortality despite lower CNS hemorrhage than neonates receiving ECLS earlier. Premature infants cannulated after 1 week had fewer CNS hemorrhages than premature infants treated with extracorporeal membrane oxygenation starting within the first week of life.

Extracorporeal membrane oxygenation for neonatal and pediatric respiratory failure: an evidence-based review of the past decade (2002-2012)

OBJECTIVE

To provide a comprehensive evidence-based review of extracorporeal membrane oxygenation for neonatal and pediatric respiratory failure.

DATA SOURCE

A thorough computerized bibliographic search of the clinical literature regarding the use of extracorporeal membrane oxygenation in the neonatal and pediatric populations.

STUDY SELECTION

Clinical trials published between January 1, 2002, and October 1, 2012, including "extracorporeal membrane oxygenation" or "ECMO" and limited to studies involving humans aged 0-18 years. Trials focused on extracorporeal membrane oxygenation for cardiac indications were excluded from this study, unless the study was evaluating ancillary therapies in conjunction with extracorporeal membrane oxygenation.

DATA EXTRACTION

Studies were evaluated for inclusion based on reporting of patient outcomes and/or strategic considerations, such as cannulation strategies, timing of extracorporeal membrane oxygenation utilization, and ancillary therapies.

DATA SYNTHESIS

Pertinent data are summarized, and the available data are objectively classified based on the value of the study design from which the data are obtained.

CONCLUSIONS

Despite a large number of published extracorporeal membrane oxygenation studies, there remains a paucity of high-quality clinical trials. The available data support continued use of extracorporeal membrane oxygenation for respiratory failure refractory to conventional therapy for neonatal and pediatric patients without significant comorbidities. Further research is needed to better quantify the benefit of extracorporeal membrane oxygenation and the utility of many therapies commonly applied to extracorporeal membrane oxygenation patients.

A 20-year experience on neonatal extracorporeal membrane oxygenation in a referral center

OBJECTIVE

Advances in treatment of neonatal respiratory failure are responsible for a decline in the number of newborns treated with extracorporeal membrane oxygenation (ECMO). The aim of this study are to determine demographic changes, focusing on time of referral, diagnosis, and respiratory parameters in neonates put on ECMO.

DESIGN

Retrospective review.

SETTING

Tertiary ECMO center.

PATIENTS

A total of 321 neonates were treated with ECMO from January 1987 to December 2006.

RESULTS

Overall number of patients increased with every 5-year period, whereby congenital diaphragmatic hernia (CDH) was the most common diagnosis (53%), followed by meconium aspiration syndrome (MAS) (21%), sepsis and/or pneumonia (13%), and others such as persistent pulmonary hypertension of the newborn (PPHN), respiratory distress syndrome (RDS), or hypoplasia of the lung (13%). Worsening severity of illness as measured by ECMO duration and days on ventilator has to be stated for all diagnoses. Nevertheless, survival rate remained stable; both overall and diagnosis-specific mortality rates did not change significantly. Of all children, 67% survived to discharge or transfer, while best rates were seen for MAS (94%), followed by sepsis and/or pneumonia (69%), CDH (62%), and other diagnoses (43%). Concerning survival rate, no difference between inborn and outborn children occurred. However, between early- and late-referred children, a referral to the ECMO center during the first 24 h of life was associated with a significantly higher rate of survival (77% versus 54%, p = 0.0004), predominantly seen for CDH (67% versus 35%, p = 0.02).

CONCLUSION

We strongly recommend timely transfer to an ECMO center in patients with CDH who are at risk of circulatory failure.

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.

Extracorporeal Membrane Oxygenation for the Treatment of Neonatal Respiratory Failure

This review discusses the use of extracorporeal membrane oxygenation (ECMO) for the treatment of respiratory failure in neonates. After briefly reviewing the early history of neonatal ECMO, the authors describe the respiratory diagnoses most often treated with ECMO and the manner in which affected neonates are deemed to have “failed” conventional therapies and thus require ECMO. After reviewing the most common indications for ECMO, factors that influence the timing of conversion to extracorporeal life support, as well as criteria that may exclude patients from receiving ECMO therapy, are described. At the conclusion of this article, the authors discuss the long-term outcomes of neonates whose respiratory disease was treated with ECMO and the costs associated with that care.

Neurologic outcome at school entry for newborns treated with extracorporeal membrane oxygenation for noncardiac indications

The neurologic outcomes at school age in children who underwent neonatal extracorporeal membrane oxygenation for noncardiac indications in a single institution surviving till the age of 5 years was determined by standardized neurologic assessment. Of 42 newborns undergoing extracorporeal membrane oxygenation, 24 underwent neurologic assessment by a single neurologist at 5 years of age. In all, 12 (50%) had a normal neurologic outcome. Lower gestational age and birth weight was found to be associated with an abnormal outcome as was septic shock as an indication for extracorporeal membrane oxygenation initiation. The number of peri-extracorporeal membrane oxygenation complications experienced by a child was associated with later epilepsy. Although invasive and implemented in critically ill infants, half of newborns undergoing extracorporeal membrane oxygenation will have a normal neurologic outcome at school age. Preexisting factors, rather than factors related to the extracorporeal membrane oxygenation itself, appear to be greater determinants of later neurologic outcomes.

Lung inflammation and pulmonary function in infants with meconium aspiration syndrome

OBJECTIVE

To evaluate the relationship between inflammation and pulmonary function, we quantified changes in inflammatory cellular profile, pro-inflammatory cytokines, and pulmonary function in intubated neonates with meconium aspiration syndrome (MAS).

METHODS

Sixteen term infants were studied. Tracheal aspirate fluids, obtained within the first 6, 24, 48, and 96 hr of life were used for measurements of: (1) cellular profile changes; (2) mRNA and protein levels for pro-inflammatory cytokines, IL-1beta, IL-6, IL-8, and TNF-alpha, using RT-PCR and ELISA. Using the same time points as above, we determined mean airway pressure, oxygenation index (OI), alveolar-arterial oxygen gradient, and arterial/alveolar oxygen ratio. Baseline tidal volume and pulmonary compliance were obtained.

RESULTS

Birth weight was 3,820 +/- 656 g, gestational age 39.8 +/- 1.4 weeks. Mean airway pressure and OI significantly decreased from the first 6-96 hr of age (P = 0.01, P = 0.027). Cell counts were elevated in the first 6 hr compared to 96 hr (17.4 x 10(6)/ml vs. 1.5 x 10(6)/ml, P < 0.05). Pro-inflammatory cytokines decreased from the first 6-96 hr: IL-1beta (187 vs. 37 pg/ml, P < 0.05); IL-6 (3,469 vs. 150 pg/ml, P < 0.05); IL-8 (16,230 vs. 6,334 pg/ml, P = 0.01).

CONCLUSIONS

MAS is associated with an inflammatory response characterized by the presence of elevated cell count and pro-inflammatory cytokines which significantly decreased by 96 hr of life. This decrease in lung inflammation has a positive correlation with corresponding decreases in mean airway pressure and oxygenation index, two parameters associated with improved pulmonary function.