Venovenous extracorporeal membrane oxygenation for respiratory failure in inotrope dependent neonates

Advances in pulmonary management and weaning from ECLS

ECMO for neonatal and pediatric respiratory failure provides gas exchange to allow lung recovery from reversible pulmonary ailments. This is a comprehensive discussion on the various strategies and advances utilized by pediatric ECLS specialists today. ECMO patients require continual monitoring, serial gasses and radiographs, near-infrared spectroscopy (NIRS - to monitor oxygen delivery to regional tissue beds), and more quality ECLS directed care. As the foundation to lung recovery, good EMCO closely monitors ECLS flow rates, sweep gasses, and membrane lung function. Mixed venous oxygen saturation (Sv02) greater than 65% indicates good oxygen delivery and sweep gas adjustments maintain PaCO2 of 40-45 mm Hg. Lung recovery ventilatory settings do not fully rest the lungs but maintain normal or nontoxic pressure and oxygen levels. Neonatal recovery settings are PIP (cm H20) of 15-20, PEEP of 5-10, ventilator rate of 12-20 and an inspiratory time of 0.5-1 s, and FiO2 of 0.3-0.5. Pediatric recovery settings are PIP (cm H20) < 25, PEEP of 5-15, ventilator rate of 10-20 and an inspiratory time of 0.8-1 s, and FiO2 of <0.5. Some studies demonstrate a higher recovery PEEP level decreases duration of ECMO, but do not demonstrate a mortality difference. Multiple adjunctive therapies such as surfactant, routine pulmonary clearance and respiratory physiotherapy, iNO, prone positioning, bronchoscopy, POCUS, CT imaging, and extubation or "awake ECLS" can significantly affect pulmonary recovery. Patience is necessary as lung recovery may take weeks or even months on the nontoxic settings. On these settings, dynamic recovery will be revealed by improvement in tidal volume, minute ventilation and radiographic pulmonary aeration, prompting discussion about weaning. When this pulmonary compliance recovery becomes evident, decreasing ECLS flow while also decreasing circuit FiO2 and/or sweep gas are common components to ECMO weaning strategies.

Venovenous vs. Venoarterial Extracorporeal Membrane Oxygenation in Infection-Associated Severe Pediatric Acute Respiratory Distress Syndrome: A Prospective Multicenter Cohort Study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been increasingly used as rescue therapy for severe pediatric acute respiratory distress syndrome (PARDS) over the past decade. However, a contemporary comparison of venovenous (VV) and venoarterial (VA) ECMO in PARDS has yet to be well described. Therefore, the objective of our study was to assess the difference between VV and VA ECMO in efficacy and safety for infection-associated severe PARDS patients.

METHODS

This prospective multicenter cohort study included patients with infection-associated severe PARDS who received VV or VA ECMO in pediatric intensive care units (PICUs) of eight university hospitals in China between December 2018 to June 2021. The primary outcome was in-hospital mortality. Secondary outcomes included ECMO weaning rate, duration of ECMO and mechanical ventilation (MV), ECMO-related complications, and hospitalization costs.

RESULTS

A total of 94 patients with 26 (27.66%) VV ECMO and 68 (72.34%) VA ECMO were enrolled. Compared to the VA ECMO patients, VV ECMO patients displayed a significantly lower in-hospital mortality (50 vs. 26.92%, p = 0.044) and proportion of neurologic complications, shorter duration of ECMO and MV, but the rate of successfully weaned from ECMO, bleeding, bloodstream infection complications and pump failure were similar. By contrast, oxygenator failure was more frequent in patients receiving VV ECMO. No significant intergroup difference was observed for the hospitalization costs.

CONCLUSION

These positive findings showed the conferred survival advantage and safety of VV ECMO compared with VA ECMO, suggesting that VV ECMO may be an effective initial treatment for patients with infection-associated severe PARDS.

Neonatal extra corporeal membrane oxygenation

Extracorporeal life support (ECLS) has been proven to be very useful in the neonatal period. For reversible respiratory and cardiac disorders, when maximal conventional measures have failed to provide life support, extracorporeal membrane oxygenation (ECMO) becomes the treatment of choice. The indications, contra-indications for ECMO, optimization of the care prior to embracing ECMO, cannulation techniques, daily management of ECMO from the practical standpoint, weaning and decannulation, complications, and special circumstances in neonatal period have been described. The follow-up of neonatal ECMO and various system manifestations necessitating careful review will be highlighted.

Venovenous Versus Venoarterial Extracorporeal Membranous Oxygenation in Inotrope Dependent Pediatric Patients With Respiratory Failure

Patients with respiratory failure requiring inotropes or vasopressors are often placed on venoarterial (VA) extracorporeal membrane oxygenation (ECMO), as venovenous (VV) ECMO does not provide direct circulatory support. This retrospective multicenter study compared outcomes for 103 pediatric patients, with hemodynamic compromise, placed on VV ECMO for respiratory failure to those placed on VA ECMO. The primary outcome was survival to hospital discharge. Fifty-seven (55%) study participants were supported on VV ECMO. The two groups had similar PRISM III scores at pediatric intensive care unit (PICU) admission, and vasoactive-inotropic scores at ECMO cannulation. More VV ECMO patients received inhaled nitric oxide (iNO) (54.4 vs. 34.8%; p = 0.04) and had a higher oxygenation index (median 41.5 vs. 19.5; p = 0.04) pre-ECMO. More VA ECMO patients had cardiac dysfunction and cardiac arrest pre-ECMO (50 vs. 14%; p < 0.0001). In univariable analysis, survival to hospital discharge was higher in the VV vs. VA ECMO group (72 vs. 44%; p = 0.005), however, in multivariable models, cannulation type was confounded by cardiopulmonary resuscitation and was not independently associated with survival. VV survivors had longer ECMO duration compared with VA survivors (median, 7 vs. 4.5 days; p = 0.036) but similar PICU and hospital days. No significant difference was noted in functional outcomes or comorbidities at discharge. Cannulation type is not independently associated with survival to hospital discharge in pediatric patients on vasoactive infusions at the time of ECMO cannulation for respiratory indications.

Venoarterial to venovenous extracorporeal life support conversion in pediatric acute respiratory distress syndrome

In patients with pediatric acute respiratory distress syndrome (PARDS) and hemodynamic compromise who need venoarterial (VA) extracorporeal life support (ECLS), we have adopted a strategy to promote early VA-to-venovenous (VV) conversion since 2018. A single-center retrospective review was performed of all 22 patients who underwent ECLS for PARDS from 2008 to 2019. Variables were analyzed to determine factors affecting initial cannulation mode and in-hospital mortality. Outcomes were compared between before and after 2018. Of the 22 patients, 9 patients underwent initial VA-support. Small patient size and severe cardiopulmonary compromise prior to ECLS favored initial VA- over VV-support. Lactate level and vasoactive inotrope score at 24 hours post-ECLS initiation predicted in-hospital mortality. After 2018, all five patients with initial VA-support were converted to VV-support at 4.4 ± 1.3 days post-ECLS initiation without complications. In-hospital mortality decreased after 2018 (3/9) compared with before (10/13) (p = 0.041) despite longer ECLS run time (723.4 ± 384.2 vs 286.5 ± 235.1 hours, p = 0.003). The number of ECLS-related complications per ECLS 1000 run hours decreased after 2018 (7.2 ± 4.2 vs 46.9 ± 66.5, p = 0.063). Our strategy to promote early VA-to-VV conversion may be worth further evaluation in larger cohort studies.

Extracorporeal Membrane Oxygenation for Adults With Refractory Septic Shock

Because of a severe dysregulation of the host response to infection, septic shock may induce a profound imbalance between oxygen consumption and delivery, which in some cases may be refractory to conventional support measures. In this setting, extracorporeal membrane oxygenation (ECMO) may help to restore this ratio. Indeed, in neonates and children, this technique is already established as a valid salvage therapy. In spite of the rapid growth in the use of ECMO in recent years, the evidence of its benefits in adult patients is weak, particularly in cases of refractory septic shock. Nevertheless, several case series have reported good outcomes in selected cases with specific management. Here we explore the links between sepsis and ECMO, starting with the basic biology underlying the two entities. We then review the published literature on the use of extracorporeal support in adult patients with septic shock and finally conclude with a review of the key points of management that can optimize the results after this critical situation.

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.

Extra-corporeal membrane oxygenation in paediatric acute respiratory distress syndrome: overrated or underutilized?

Extracorporeal membrane oxygenation (ECMO) is a modified form of cardiopulmonary bypass which may provide support for severe cardiorespiratory failure including paediatric acute respiratory distress syndrome (PARDS). While ECMO was initially demonstrated to successfully support neonates with severe respiratory failure, the use of ECMO has expanded rapidly to support both paediatric and adult respiratory failure. Extracorporeal Life Support Organization (ELSO) registry data shows that the use of ECMO for paediatric respiratory failure has expanded rapidly over the past decades with increasing use of venovenous ECMO. Despite the increasing complexity of children supported by ECMO for ARDS, outcomes have remained consistent with survival to hospital discharge greater than 50%. ECMO complications are still common and potentially devastating, especially neurological complications. There is grade 1 evidence to support the use of ECMO in both neonatal and adult respiratory failure but evidence in paediatric respiratory failure is confined to case series and case-control studies. While there are no published guidelines for use of ECMO in PARDS, in particular no clearly defined inclusion and exclusion criteria, current evidence suggests that children with severe ARDS may benefit from ECMO support, with survival to hospital discharge equivalent or better than conventional management in children with severe ARDS.

Venoarterial extracorporeal membrane oxygenation support for neonatal and pediatric refractory septic shock: more than 15 years of learning

The objective of the study was to report our institutional experience in the management of children and newborns with refractory septic shock who required venoarterial extracorporeal membrane oxygenation (VA ECMO) treatment, and to identify patient-and infection-related factors associated with mortality. This is a retrospective case series in an intensive care unit of a tertiary pediatric center. Inclusion criteria were patients ≤ 18 years old who underwent a VA ECMO due to a refractory septic shock due to circulatory collapse. Patient conditions and support immediately before ECMO, analytical and hemodynamic parameter evolution during ECMO, and post-canulation outcome data were collected. Twenty-one patients were included, 13 of them (65%) male. Nine were pediatric and 12 were newborns. Median septic shock duration prior to ECMO was 29.5 h (IQR, 20-46). Eleven patients (52.4%) suffered cardiac arrest (CA). Neonatal patients had worse Sepsis Organ Failure Assessment (SOFA) score, Oxygenation Index and PaO₂/FiO₂ ratio, blood gas analysis, lactate levels, and left ventricular ejection fraction compared to pediatric patients. Survival was 33.3% among pediatric patients (60% if we exclude pneumococcal cases) and 50% among newborns. Hours of sepsis evolution and mean airway pressure (MAP) prior to ECMO were significantly higher in the non-survivor group. CA was not a predictor of mortality. Streptococcus pneumoniae infection was a mortality risk factor. There was an improvement in survival during the second period, from 14.3 to 57.2%, related to shorter sepsis evolution before ECMO placement, better candidate selection, and greater ECMO support once the patient was placed.

CONCLUSION

Patients with refractory septic shock should be transferred precociously to a referral ECMO center. However, therapy should be used with caution in patients with vasoplegic pattern shock or S. pneumoniae sepsis. What is Known: • Children with refractory septic shock have significant mortality rates, and although ECMO is recommended, overall survival is low. • There are no studies regarding characteristics of infections as predictors of pediatric survival in ECMO. What is New: • Septic children should be transferred precociously to referral ECMO centers during the first hours if patients do not respond to conventional therapy. • Treatment should be used with caution in patients with vasoplegic pattern shock or S. pneumoniae sepsis.

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.

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.

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.

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.

Extracorporeal life support for the neonatal cardiac patient: outcomes and new directions

Extracorporeal life support is an important therapy for neonates with life-threatening cardiopulmonary failure. Utilization of extracorporeal life support in neonates with congenital heart disease has increased dramatically during the past three decades. Despite increased usage, overall survival in these patients has changed very little and extracorporeal life support-related morbidity, including bleeding, neurologic injury, and renal failure, remains a major problem. Although survival is lower and neurologic complications are higher in premature infants than term infants, cardiac extracorporeal life support including extracorporeal cardiopulmonary resuscitation is effective in preventing death in many of these high-risk patients. Miniaturized ventricular assist devices and compact integrated extracorporeal life support systems are being developed to provide additional therapeutic options for neonates.

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.

Effect of venovenous extracorporeal membrane oxygenation on the heart in a healthy piglet model

Background

Cardiac function is important for patients treated by venovenous extracorporeal membrane oxygenation (VV ECMO), but data about the effect of VV ECMO on the heart in nonneonates is absent. We studied the effect of VV ECMO on cardiac performance, cardiomyocyte and mitochondria in an animal model.

Methods

Twelve farm piglets were randomly assigned into two groups: control group and ECMO group. In the ECMO group, ECMO cannulaes were placed and ECMO was instituted. Hemodynamics was recorded at baseline, 1 hour after induction, and every 4 hours thereafter, to assess the cardiac performance. All animals were monitored for 24 hours and were euthanized and myocardium was harvested. Myocardial histology, ultrastructure of cardiomyocyte and mitochondria were observed, and activities of mitochondrial complexes I-V were measured, to assess the effect to cardiomyocyte and mitochondria.

Results

Hemodynamics were stable in each group of animals throughout the experiment. Interstitial edema, disorderd and dissolved of focal myofilament, morphological deformations of mitochondria were observed in the ECMO group. The activities of mitochondrial complexes were decreased in the ECMO group, and complex I and IV reached significance.

Conclusions

VV ECMO therapy is associated with changes of ultrastructure and function of cardiomyocyte and mitochondria, inducing myocardium injury. However, the injury was mild and had no effect on the cardiac performance for healthy piglets.

Use of venovenous extracorporeal life support in pediatric patients for cardiac indications: a review of the Extracorporeal Life Support Organization registry

OBJECTIVE

To describe survival outcomes for pediatric patients supported on venovenous extracorporeal life support with cardiac indications and identify predictors of successful application of venovenous extracorporeal life support.

DESIGN

Retrospective review of Extracorporeal Life Support Organization registry database.

SETTING

Data reported from extracorporeal membrane oxygenation centers to the Extracorporeal Life Support Organization.

PATIENTS

Patients ≤18 yrs of age with cardiac diagnoses initiated on venovenous extracorporeal life support during 1985 to 2007.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 8,551 reported pediatric extracorporeal life support cases for cardiac indications during 1985 to 2007, 133 patients received venovenous extracorporeal life support (1.6%); 56 (42%) survived to hospital discharge, comprising the venovenous success group. Of 77 (58%) in the venovenous failure group, 45 (34%) died on venovenous extracorporeal life support and 32 (24%) were converted to venoarterial extracorporeal life support. Median duration of extracorporeal life support course was shorter in the venovenous success group (76 vs. 133 hrs, odds ratio 1.01, 95% confidence interval 1.00-1.01). In the univariate analysis, patients in the venovenous failure group had lower median arterial pH (odds ratio 0.06, 95% confidence intervals 0.01-0.61) and higher PaO(2) (odds ratio 1.02, 95% confidence interval 1.00-1.04). Complications from extracorporeal life support, including receipt of renal replacement therapy (odds ratio 4.35, 95% confidence interval 1.87-10.11), surgical hemorrhage (odds ratio 2.56, 95% confidence interval 1.05-6.25), use of inotropic infusions (odds ratio 2.53, 95% confidence interval 1.24-5.15), and infections (odds ratio 4.99, 95% confidence interval 1.07-23.25), were associated with increased odds for venovenous failure. In a multivariable model, the highest PaO(2) (PaO(2) ≥52 torr) compared to the lowest (PaO(2) ≤ 22 torr) (odds ratio 3.75, 95% confidence interval 1.11-12.57), and use of renal replacement therapy (odds ratio 4.35, 95% confidence interval 1.8710.11) were associated with increased odds of venovenous failure.

CONCLUSION

Venovenous extracorporeal life support appears to be an appropriate choice in some children with cardiac failure but better definition of this population is needed.

Improved survival in venovenous vs venoarterial extracorporeal membrane oxygenation for pediatric noncardiac sepsis patients: a study of the Extracorporeal Life Support Organization registry

BACKGROUND/PURPOSE

There are few studies comparing venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO) in pediatric noncardiac sepsis patients.

METHODS

Following approval, we reviewed the Extracorporeal Life Support Organization registry data from 1990 to 2008 for patients 0 to 18 years with a diagnosis of sepsis and without diagnosis of congenital heart disease. Survival to discharge was compared between VA and VV ECMO using χ(2) analysis and multivariable logistic regression.

RESULTS

Four thousand three hundred thirty-two ECMO runs were reviewed, 3256 VA (75%) and 1076 VV (25%). A majority of VA modality was noted in each decade studied. Overall survival was 68% and was higher in VV (79%) than in VA ECMO (64%, P < .001). Survival decreased with increasing age (73% in newborns ≤ 1 month, 40% in children 1 month to 12 years, and 32% in adolescents >12 years, P < .001). VA ECMO had increased mortality risk after adjustment for age, use of vasoactive agents, and advanced respiratory support (odds ratio, 2.06; 95% confidence interval, 1.74-2.44; P < .001).

CONCLUSIONS

These data demonstrate improved survival in VV vs. VA ECMO in select pediatric septic patients without congenital heart disease. When technically feasible, physicians should consider VV ECMO as first therapeutic choice in this patient population.

Factors associated with survival in pediatric extracorporeal membrane oxygenation--a single-center experience

AIM

We aimed to examine outcomes of extracorporeal membrane oxygenation (ECMO) therapy in the pediatric population and identify pre-ECMO and on-ECMO characteristics that are associated with survival.

METHODS

We retrospectively reviewed the ECMO records at our institution between 1999 and 2008 and selected pediatric patients who were cannulated for respiratory failure or hemodynamic instability resistant to conventional interventions. We recorded details of pre-ECMO clinical characteristics, including blood gas variables and mechanical ventilatory support, and details of ECMO therapy including survival off ECMO and to hospital discharge. Predictors of survival were analyzed using logistic regression modeling and a prediction algorithm was developed.

RESULTS

Of the 445 ECMO runs, data from 58 consecutive patients were analyzed: 57% were successfully decannulated, and 48% survived to discharge from the hospital. The cohort included 32 (55%) female patients, 22 postoperative patients (38%), and 15 (26%) with an immunosuppressive condition, with a median age of 5 years and weight 19.5 kg, The mean duration of pre-ECMO respiratory support was 3 days, in the form of high-frequency oscillatory ventilation (n = 28, 48%) and conventional mechanical ventilation (n = 13, 22%). The median duration (interquartile range) of ECMO support was 142 hours (60, 321) or 5.9 days. Pre-ECMO pH above 7.2 (P < .001) and oxygenation index below 35 (P = .021) were associated with the highest survival rates. Pre-ECMO PaCO(2) and duration of mechanical ventilation were not associated with survival.

CONCLUSIONS

Based on our results, ECMO therapy should be considered early in children with oxygenation index greater than 35 with worsening metabolic status. The restriction of ECMO based on ventilator days alone needs to be revisited in this era of lung protective ventilation.

Case report: pediatric liver retransplantation on an extracorporeal membrane oxygenation-dependent child

We describe the perioperative management of a venovenous extracorporeal membrane oxygenator-dependent child requiring liver retransplantation after emergent hepatectomy because of an ischemic liver graft. This child required renal replacement and inotropic support as well as treatment for heparin-induced thrombocytopenia (HIT). We describe each step in this child's perioperative management leading to the successful liver retransplantation. This is the first description, to our knowledge, of a pediatric patient undergoing liver transplantation while supported by extracorporeal membrane oxygenation (ECMO).

Decompressive laparotomy for abdominal compartment syndrome in children: before it is too late

PURPOSE

Abdominal compartment syndrome (ACS) in children is an infrequently reported, rapidly progressive, and often lethal condition underappreciated in the pediatric population. This underrecognition can result in a critical delay in diagnosis causing increased morbidity and mortality. This study examines the clinical course of patients treated for ACS at our institution.

METHODS

A review of children requiring an emergency laparotomy (n = 264) identified 26 patients with a diagnosis of ACS. ACS was defined as sustained intraabdominal hypertension (bladder pressure >12 mm Hg) that was associated with new onset organ dysfunction or failure.

RESULTS

Patients ranged in age from 3 months to 17 years old and were cared for in the pediatric intensive care unit (PICU). Twenty-seven percent (n = 7) were transferred from referring hospitals, 50% (n = 13) were admitted directly from the emergency department, and 23% (n = 6) were inpatients before being transferred to PICU. Admission diagnoses included infectious enterocolitis (n = 12), postsurgical procedure (n = 10), and others (n = 4). Patients progressed to ACS rapidly, with most requiring decompressive laparotomy within 8 hours of PICU admission (range, <1-96 hours). Preoperatively, all patients had maximum ventilatory support and oliguria, 85% (n = 22) required vasopressors/inotropes, and 31% (n = 8) required hemodialysis. Mean bladder pressure was 25 mm Hg (range, 12-44 mm Hg). In 42% (n = 11), cardiac arrest preceeded decompressive laparotomy. All patients showed evidence of tissue ischemia before decompressive laparotomy with an average preoperative lactate of 8 (range, 1.2-20). Decompressive laparotomy was done at the bedside in the PICU in 13 patients and in the operating room in 14 patients. Abdominal wounds were managed with open vacuum pack or silastic silo dressings. Physiologic data including fluid resuscitation, oxygen index, mean airway pressure, vasopressor score, and urine output were recorded at 6-hour intervals beginning 12 hours before decompressive laparotomy and extending 12 hours after operation. The data demonstrate improvement of all physiologic parameters after decompressive laparotomy except for urine output, which continued to be minimal 12 hours post intervention. Mortality was 58% (n = 15) overall. The only significant factor related to increased mortality was bladder pressure (P = .046; odds ratio, 1.258). Cardiac arrest before decompressive laparotomy, need for hemodialysis, and transfer from referring hospital also trended toward increased mortality but did not reach significance.

CONCLUSION

Abdominal compartment syndrome in children carries a high mortality and may be a consequence of common childhood diseases such as enterocolitis. The diagnosis of ACS and the potential need for emergent decompressive laparotomy may be infrequently discussed in the pediatric literature. Increased awareness of ACS may promote earlier diagnosis, treatment, and possibly improve outcomes.

Calculating mixed venous saturation during veno-venous extracorporeal membrane oxygenation

INTRODUCTION

Recirculation (R), the shunting of arterial blood back into to the venous lumen, commonly occurs during veno-venous extracorporeal membrane oxygenation (VV-ECMO) and renders the monitoring of the venous line oxygen saturation no longer reflective of patient mixed venous oxygen saturation (S(V)O(2)). Previously, we failed to prove the hypothesis that, once R is known, it is possible to calculate the S(V)O(2) of a patient on VV-ECMO. We hypothesize that we can calculate S(V)O(2) during VV-ECMO if we account for and add an additional correction factor to our model for dissolved oxygen content. Therefore, the purpose of this study is to derive a more accurate model that will allow clinicians to determine S(V)O(2) during VV-ECMO when ultrasound dilution is being used to quantify R.

METHODS

Using an extracorporeal circuit primed with fresh porcine blood, two stocks of blood were produced; (1) arterial blood (AB), and (2) venous blood (VB). To mimic recirculation, the AB and VB were mixed together in precise ratios using syringes and a stopcock manifold. Six paired stock AB/VB sets were prepared. Two sets were mixed at 20% R increments and 4 sets were mixed at 10% R increments. The partial pressure of oxygen (pO(2) ) and oxygen (O(2)) saturation of the stock blood and resultant mixed blood was determined. The original model was modified by modeling the residual errors with linear regression.

RESULTS

When using the original model, as the partial pressure of arterial oxygen (P(a)O( 2)) of the stock AB increased, the calculated S(V)O(2) was higher than actual, especially at higher R levels. An iteration of the original model incorporating the P(a)O(2) level (low, medium, high) and R was derived to fit the data.

CONCLUSIONS

The original model using R and circuit saturations for the calculation of S(V)O( 2) in VV-ECMO patients is an oversimplification that fails to consider the influence of the high pO(2) of arterial blood during therapy. In the future, further improvements in this model will allow clinicians accurately to calculate S(V)O(2) in conjunction with recirculation measurements.

Clinical impact of vasopressin infusion on hemodynamics, liver and renal function in pediatric patients

OBJECTIVE

To study effects of vasopressin on hemodynamic, clinical, and laboratory variables in children with advanced vasodilatory shock.

DESIGN AND SETTING

Retrospective study in a multidisciplinary tertiary pediatric critical care unit.

PATIENTS AND PARTICIPANTS

Patients (n = 117; 32 noncardiac, 85 postcardiac surgery) requiring intravenous vasopressin infusion longer than 60 min for advanced shock (January 2004 to December 2005).

INTERVENTIONS

Vasopressin infusion (n =157).

MEASUREMENTS AND RESULTS

Both cardiac and noncardiac patients showed a significant decrease in inotrope requirement without change in central venous saturation or lactate during infusion. Both groups had increased urea and creatinine and decreased urine output with longer duration/higher cumulative dose of vasopressin. There was a significant increase in conjugated bilirubin level in the noncardiac group during vasopressin infusion; noncardiac patients showed higher AST levels with higher cumulative dose or longer duration of infusion. Postcardiac surgical patients showed a trend towards normal INR values which persisted after vasopressin infusion. Platelet counts were significantly lower during infusion in both groups.

CONCLUSIONS

Vasopressin infusion improved the hemodynamic state in advanced shock without compromising cardiac function. Urine output and creatinine levels were adversely affected but were reversible. This effect was more pronounced with higher dose or duration of infusion. There was no major effect on liver function but a significant reduction in platelet counts. These data suggest that vasopressin is useful in states of vasodilatory shock with limitations regarding to its adverse renal effects and on platelet counts.

Versatile use of extra-corporeal life support to resuscitate acute respiratory distress patients

Extra-corporeal life support (ECLS) has been applied successfully to congenital respiratory defects but less optimally to acquired pulmonary failure. We extended this support to certain extreme complexities of patients with acute respiratory distress. From January 2003 to June 2005, 16 (nine men and seven women) patients refractory to ventilator support were treated with ECLS. Their median age was 32.4 years (1.5-70). The triggering events were pulmonary haemorrhage (n = 4), pneumonia (n = 7), aspiration (n = 2) and pancreatitis (n = 3). The indications for support were hypoxaemia in 13 and hypercapnia in three patients. Ten (63%) met the criteria of fast entry. Thirteen (81%) received veno-venous (V-V) mode support and the other three received veno-arterial mode support initially, but then converted to V-V mode after sufficient oxygenation stabilised haemodynamics. Initial pump flow was maximised to improve (mean 3250 +/- 1615 ml/min) to improve the oxygenation. Four patients with active pulmonary haemorrhage were heparin free in the first 12-24 h of support without complications. Excluding one prematurely terminated patient because of brain permanent damage, the duration of support was 162 +/- 95 h (67-363). Eleven (69%) weaned successfully from ECLS and 10 (63%) discharged and regained normal pulmonary performance in a median of 26.8 months follow-up. Pulmonary support using ECLS was feasible in selected patients with acute respiratory distress. Modification of guidelines for liberal use, early deployment before secondary organ damage and prevention of complications during support were the key to final success.

Update on extracorporeal life support 2004

Since its beginnings in 1989, the Extracorporeal Life Support Organization (ELSO) Registry has collated and reported data on over 30,000 patients. The majority of patients entered into the Registry have been neonates with respiratory failure from meconium aspiration, persistent pulmonary hypertension, or congenital diaphragmatic hernia. These patients suffer from refractory hypoxemia; thus, this supportive technique came to be called "Extracorporeal Membrane Oxygenation (ECMO)" for its ability to provide excellent gas exchange. With advances in prevention, diagnosis, and treatment measures for neonatal respiratory failure, need for ECMO support has fallen from the peak of 1500 cases in the early 1990s to 800 cases annually. Sixty-six percent (over 19,000) of patients in the Registry are under the category of neonatal respiratory failure, with a 77% overall survival reported to discharge. The success of neonatal ECMO has led to expansion of the field to pediatric, cardiac, and adult patients. An average of 200 pediatric patients receive ECMO for respiratory failure per year with an overall survival of 55%. Adult respiratory failure patients form a smaller group, with less than 100 cases reported to the ELSO registry per year. Survival mirrors that noted in the pediatric ECMO population. The application of ECMO or related techniques continues to increase for cardiac failure across all age groups. Overall survival in cardiac patients ranges from 33% to 43%. A novel form of extracorporeal support is "ECPR" or ECMO during cardiac arrest. Bypass circuits and equipment can be set up and instituted within a very short period of time in this circumstance, thus the name "rapid deployment ECMO" has become associated with this form of support. Overall survival in the near-600 patients placed on ECMO during resuscitation is 40%.