Seven-day in vivo testing of a novel, low-resistance, pumpless pediatric artificial lung for long-term support.

INTRODUCTION: For children with end-stage lung disease that cannot wean from extracorporeal life support (ECLS), a wearable artificial lung would permit extubation and provide a bridge to recovery or transplantation. We evaluate the function of the novel Pediatric MLung-a low-resistance, pumpless artificial lung developed specifically for children-in healthy animal subjects. METHODS: Adolescent "mini sheep" weighing 12-20 kg underwent left thoracotomy, cannulation of the main pulmonary artery (PA; inflow) and left atrium (outflow), and connection to the MLung. RESULTS: Thirteen sheep were studied; 6 were supported for 7 days. Mean PA pressure was 23.9 ± 6.9 mmHg. MLung blood flow was 633±258 mL/min or 30.0 ± 16.0% of CO. MLung pressure drop was 4.4 ± 3.4 mmHg. Resistance was 7.2 ± 5.2 mmHg/L/min. Device outlet oxygen saturation was 99.0 ± 3.3% with inlet saturation 53.8 ± 7.3%. Oxygen delivery was 41.1 ± 18.4 mL O2/min (maximum 84.9 mL/min) or 2.8 ± 1.5 mL O2/min/kg. Platelet count significantly decreased; no platelet transfusions were required. Plasma free hemoglobin significantly increased only on day 7, at which point 2 of the animals had plasma free hemoglobin levels above 50 mg/dL. CONCLUSION: The MLung provides adequate gas exchange at appropriate blood flows for the pediatric population in a PA-to-LA configuration. Further work remains to improve the biocompatibility of the device. LEVEL OF EVIDENCE: N/A.

A pumpless artificial lung without systemic anticoagulation: The Nitric Oxide Surface Anticoagulation system.

BACKGROUND: Artificial lungs have the potential to serve as a bridge to transplantation or recovery for children with end-stage lung disease dependent on extracorporeal life support, but such devices currently require systemic anticoagulation. We describe our experience using the novel Nitric Oxide (NO) Surface Anticoagulation (NOSA) system-an NO-releasing circuit with NO in the sweep gas-with the Pediatric MLung-a low-resistance, pumpless artificial lung. METHODS: NO flux testing: MLungs (n = 4) were tested using veno-venous extracorporeal life support in a sheep under anesthesia with blood flow set to 0.5 and 1 L/min and sweep gas blended with 100 ppm NO at 1, 2, and 4 L/min. NO and NO2 were measured in the sweep and exhaust gas to calculate NO flux across the MLung membrane. Pumpless implants: Sheep (20-100 kg, n = 3) underwent thoracotomy and cannulation via the pulmonary artery (device inflow) and left atrium (device outflow) using cannulae and circuit components coated with an NO donor (diazeniumdiolated dibutylhexanediamine; DBHD-N2O2) and argatroban. Animals were connected to the MLung with 100 ppm NO in the sweep gas under anesthesia for 24 h with no systemic anticoagulation after cannulation. RESULTS: NO flux testing: NO flux averaged 3.4 ± 1.0 flux units (x10-10 mol/cm2/min) (human vascular endothelium: 0.5-4 flux units). Pumpless implants: 3 sheep survived 24 h with patent circuits. MLung blood flow was 716 ± 227 mL/min. Outlet oxygen saturation was 98.3 ± 2.6%. Activated clotting time was 151±24 s. Platelet count declined from 334,333 ± 112,225 to 123,667 ± 7,637 over 24 h. Plasma free hemoglobin and leukocyte and platelet activation did not significantly change. CONCLUSIONS: The NOSA system provides NO flux across a gas-exchange membrane of a pumpless artificial lung at a similar rate as native vascular endothelium and achieves effective local anticoagulation of an artificial lung circuit for 24 h.

Prolonged (≥24 Hours) Normothermic (≥32 °C) Ex Vivo Organ Perfusion: Lessons From the Literature.

For 2 centuries, researchers have studied ex vivo perfusion intending to preserve the physiologic function of isolated organs. If it were indeed possible to maintain ex vivo organ viability for days, transplantation could become an elective operation with clinicians methodically surveilling and reconditioning allografts before surgery. To this day, experimental reports of successfully prolonged (≥24 hours) organ perfusion are rare and have not translated into clinical practice. To identify the crucial factors necessary for successful perfusion, this review summarizes the history of prolonged normothermic ex vivo organ perfusion. By examining successful techniques and protocols used, this review outlines the essential elements of successful perfusion, limitations of current perfusion systems, and areas where further research in preservation science is required.

Physiology of Extracorporeal Gas Exchange.

Circulating venous blood outside the body, through an artificial lung (membrane oxygenator), and returning oxygenated blood to the patient is extracorporeal gas exchange. Oxygen and carbon dioxide exchange in a membrane lung is controlled by regulating blood flow, blood composition, and device design. With this control, lung function can be replaced for weeks by artificial organs. © 2020 American Physiological Society. Compr Physiol 10:879-891, 2020.

Splenic development and injury in premature lambs supported by the artificial placenta.

INTRODUCTION: The purpose of this study is to evaluate splenic effects during artificial placenta (AP) support. METHODS: AP lambs (118-121 d, n = 14) were delivered and placed on the AP support for a goal of 10-14 days. Cannulation used right jugular drainage and umbilical vein reinfusion. Early (ETC; 115-120 d; n = 7) and late (LTC; 125-131 d; n = 7) tissue controls were delivered and immediately sacrificed. Spleens were formalin fixed, H&E stained, and graded for injury, response to inflammation, and extramedullary hematopoiesis (EMH). CD68 and CD163 stains were used to assess for macrophage activation and density. Clinical variables were correlated with splenic scores. Groups were compared using Fisher's Exact Test and descriptive statistics. p < 0.05 indicated significance. RESULTS: Mean survival for AP lambs was 12 ±â€¯5 d. There was no necrosis found in any of the groups. Vascular congestion and sinusoidal histiocytosis did not significantly differ between AP and control groups (p = 0.72; p = 0.311). There were significantly more pigmented macrophages (p = 0.008), CD163 (p = <0.001), and CD68 (p = <0.001) stained cells in the AP group. ETC and LTC demonstrated more EMH than AP spleens (p = <0.001). CONCLUSIONS: During AP support, spleens appear to develop normally and exhibit an appropriate inflammatory response. After initiation of AP support, EMH transitions away from the spleen. STUDY TYPE: Research Paper/Therapeutic Potential. LEVEL OF EVIDENCE: N/A.

An Artificial Placenta Protects Against Lung Injury and Promotes Continued Lung Development in Extremely Premature Lambs.

An artificial placenta (AP) utilizing extracorporeal life support (ECLS) could protect premature lungs from injury and promote continued development. Preterm lambs at estimated gestational age (EGA) 114-128 days (term = 145) were delivered by Caesarian section and managed in one of three groups: AP, mechanical ventilation (MV), or tissue control (TC). Artificial placenta lambs (114 days EGA, n = 3; 121 days, n = 5) underwent venovenous (VV)-ECLS with jugular drainage and umbilical vein reinfusion for 7 days, with a fluid-filled, occluded airway. Mechanical ventilation lambs (121 days, n = 5; 128 days, n = 5) underwent conventional MV until failure or maximum 48 hours. Tissue control lambs (114 days, n = 3; 121 days, n = 5; 128 days, n = 5) were sacrificed at delivery. At the conclusion of each experiment, lungs were procured and sectioned. Hematoxylin and eosin (H&E) slides were scored 0-4 in seven injury categories, which were summed for a total injury score. Slides were also immunostained for platelet-derived growth factor receptor (PDGFR)-α and α-actin; lung development was quantified by the area fraction of double-positive tips of secondary alveolar septa. Support duration of AP lambs was 163 ± 9 (mean ± SD) hours, 4 ± 3 for early MV lambs, and 40 ± 6 for late MV lambs. Total injury scores at 121 days were 1.7 ± 2.1 for AP vs. 5.5 ± 1.6 for MV (p = 0.02). Using immunofluorescence, double-positive tip area fraction at 121 days was 0.017 ± 0.011 in AP lungs compared with 0.003 ± 0.003 in MV lungs (p < 0.001) and 0.009 ± 0.005 in TC lungs. At 128 days, double-positive tip area fraction was 0.012 ± 0.007 in AP lungs compared with 0.004 ± 0.004 in MV lungs (p < 0.001) and 0.016 ± 0.009 in TC lungs. The AP is protective against lung injury and promotes lung development compared with mechanical ventilation in premature lambs.

The artificial placenta: Continued lung development during extracorporeal support in a preterm lamb model.

PURPOSE: An artificial placenta (AP) utilizing extracorporeal life support (ECLS) could avoid the harm of mechanical ventilation (MV) while allowing the lungs to develop. METHODS: AP lambs (n = 5) were delivered at 118 days gestational age (GA; term = 145 days) and placed on venovenous ECLS (VV-ECLS) with jugular drainage and umbilical vein reinfusion. Lungs remained fluid-filled. After 10 days, lambs were ventilated. MV control lambs were delivered at 118 ("early MV"; n = 5) or 128 days ("late MV"; n = 5), and ventilated. Compliance and oxygenation index (OI) were calculated. After sacrifice, lungs were procured and H&E-stained slides scored for lung injury. Slides were also immunostained for PDGFR-α and α-actin; alveolar development was quantified by the area fraction of alveolar septal tips staining double-positive for both markers. RESULTS: Compliance of AP lambs was 2.79 ±â€¯0.81 Cdyn compared to 0.83 ±â€¯0.19 and 3.04 ±â€¯0.99 for early and late MV, respectively. OI in AP lambs was lower than early MV lambs (6.20 ±â€¯2.10 vs. 36.8 ±â€¯16.8) and lung injury lower as well (1.8 ±â€¯1.6 vs. 6.0 ±â€¯1.2). Double-positive area fractions were higher in AP lambs (0.012 ±â€¯0.003) than early (0.003 ±â€¯0.0005) and late (0.004 ±â€¯0.002) MV controls. CONCLUSIONS: Lung development continues and lungs are protected from injury during AP support relative to mechanical ventilation. LEVEL OF EVIDENCE: n/a (basic/translational science).

Gastrointestinal mucosal development and injury in premature lambs supported by the artificial placenta.

BACKGROUND: An Artificial Placenta (AP) utilizing extracorporeal life support (ECLS) could revolutionize care of extremely premature newborns, but its effects on gastrointestinal morphology and injury need investigation. METHODS: Lambs (116-121days GA, term=145; n=5) were delivered by C-section, cannulated for ECLS, had total parenteral nutrition (TPN) provided, and were supported for 7days before euthanasia. Early and Late Tissue Controls (ETC, n=5 and LTC, n=5) delivered at 115-121days and 125-131days, respectively, were immediately sacrificed. Standardized jejunal samples were formalin-fixed for histology. Crypt depth (CD), villus height (VH), and VH:CD ratios were measured. Measurements also included enterocyte proliferation (Ki-67), Paneth cell count (Lysozyme), and injury scores (H&E). ANOVA and Chi Square were used with p<0.05 considered significant. RESULTS: CD, VH, and VH:CD were similar between groups (p>0.05). AP demonstrated more enterocyte proliferation (95.7±21.8) than ETC (49.4±23.4; p=0.003) and LTC (66.1+11.8; p=0.04), and more Paneth cells (81.7±17.5) than ETC (41.6±7.0; p=0.0005) and LTC (40.7±8.2, p=0.0004). Presence of epithelial injury and congestion in the bowel of all groups were not statistically different. No villus atrophy or inflammation was present in any group. CONCLUSIONS: This suggests preserved small bowel mucosal architecture, high cellular turnover, and minimal evidence of injury. STUDY TYPE: Research paper/therapeutic potential. LEVEL OF EVIDENCE: N/A.

Perfluorocarbons Prevent Lung Injury and Promote Development during Artificial Placenta Support in Extremely Premature Lambs.

BACKGROUND: Extremely premature neonates suffer high morbidity and mortality. An artificial placenta (AP) using extracorporeal life support (ECLS) is a promising therapy. OBJECTIVES: We hypothesized that intratracheal perfluorocarbon (PFC) instillation during AP support would reduce lung injury and promote lung development relative to intratracheal amniotic fluid or crystalloid. METHODS: Lambs at an estimated gestational age (EGA) 116-121 days (term 145 days) were placed on venovenous ECLS with jugular drainage and umbilical vein reinfusion and intubated. Airways were managed by the instillation of amniotic fluid and tracheal occlusion (TO; n = 4), or lactated Ringer's (LR; n = 4) or perfluorodecalin (a PFC) without occlusion (n = 4). After 7 days, the animals were sacrificed. Early (EGA 116-121 days) and late (EGA 125-131 days) tissue control lambs were delivered and sacrificed. Lungs were formalin-inflated to 30 cm H2O and sectioned for histology. Injury was scored by an unbiased pathologist. Slides were immunostained for PDGFR-α and α-actin; development was quantified by the area fraction of double-positive tips. Surfactant protein-C (SP-C) concentration in bronchoalveolar lavage fluid was quantified using ELISA. RESULTS: Total injury scores were lower in PFC lungs (1.8 ± 1.7) than in TO (6.5 ± 2.1; p = 0.01) and LR lungs (5.5 ± 2.4; p = 0.01). The area fraction of double-positive alveolar tips appeared higher in PFC lungs than in TO lungs (0.18 ± 0.007 vs. 0.008 ± 0.004; p = 0.07). SP-C concentration was higher in PFC lungs than in TO lungs (37.9 ± 7.6 vs. 20.0 ± 5.4 pg/mL; p = 0.005), and both early (12.4 ± 1.7 g/mL; p = 0.007) and late tissue control lungs (15.1 ± 5.0 pg/mL; p = 0.0008). CONCLUSION: During AP support, intratracheal PFC prevents lung injury and promotes normal lung development better than crystalloid or amniotic fluid with TO.

Portable Nitric Oxide (NO) Generator Based on Electrochemical Reduction of Nitrite for Potential Applications in Inhaled NO Therapy and Cardiopulmonary Bypass Surgery.

A new portable gas phase nitric oxide (NO) generator is described for potential applications in inhaled NO (INO) therapy and during cardiopulmonary bypass (CPB) surgery. In this system, NO is produced at the surface of a large-area mesh working electrode by electrochemical reduction of nitrite ions in the presence of a soluble copper(II)-ligand electron transfer mediator complex. The NO generated is then transported into gas phase by either direct purging with nitrogen/air or via circulating the electrolyte/nitrite solution through a gas extraction silicone fiber-based membrane-dialyzer assembly. Gas phase NO concentrations can be tuned in the range of 5-1000 ppm (parts per million by volume for gaseous species), in proportion to a constant cathodic current applied between the working and counter electrodes. This new NO generation process has the advantages of rapid production times (5 min to steady-state), high Faraday NO production efficiency (ca. 93%), excellent stability, and very low cost when using air as the carrier gas for NO (in the membrane dialyzer configuration), enabling the development of potentially portable INO devices. In this initial work, the new system is examined for the effectiveness of gaseous NO to reduce the systemic inflammatory response (SIR) during CPB, where 500 ppm of NO added to the sweep gas of the oxygenator or to the cardiotomy suction air in a CPB system is shown to prevent activation of white blood cells (granulocytes and monocytes) during extracorporeal circulation with cardiotomy suction conducted with five pigs.

Pushing the boundaries of ECLS: Outcomes in <34 week EGA neonates.

PURPOSE: Extracorporeal life support (ECLS) is usually reserved for infants ≥34weeks estimated gestational age (EGA) owing to concerns about increased mortality and incidence of intracranial hemorrhage (ICH). We sought to characterize survival, rates of ICH, and complications in <34week EGA neonates placed on ECLS. METHODS: 752 neonates of EGA 29-34weeks were identified in the Extracorporeal Life Support Organization (ELSO) Registry (1976-2008). Data analyzed included birthweight, survival, pre-ECLS conditions, ventilatory parameters and complications (including ICH and other neurological outcomes). Data were compared using t-test, Chi-square and logistic regression analyses. RESULTS: When compared to survival rates of 34week EGA neonates (58%), survival was statistically different for 29-33week EGA (48%, p=0.05). No significant difference in ICH incidence was seen between the 29-33week and 34week groups (21% vs. 17%, respectively), but a significant difference was seen in the incidence of cerebral infarct between groups (22% for 29-33weeks vs. 16% for 34weeks; p=0.03). ICH and survival did not correlate with EGA during logistic regression analysis. CONCLUSIONS: Though rates of survival and cerebral infarction were worse at 29-33weeks EGA compared with 34weeks, these differences were modest and may be clinically acceptable. This suggests that EGA<34weeks may not be an absolute contraindication to use of ECLS. LEVEL OF EVIDENCE: III.

Physiology of Gas Exchange During ECMO for Respiratory Failure.

Management of gas exchange using extracorporeal membrane oxygenation (ECMO) in respiratory failure is very different than management when the patient is dependent on mechanical ventilation. All the gas exchange occurs in the membrane lung, and the arterial oxygenation is the result of mixing the ECMO blood with the native venous blood. To manage patients on ECMO, it is essential to understand the physiology described in this essay.

Development and validation of the pediatric risk estimate score for children using extracorporeal respiratory support (Ped-RESCUERS).

PURPOSE: To develop and validate the Pediatric Risk Estimation Score for Children Using Extracorporeal Respiratory Support (Ped-RESCUERS). Ped-RESCUERS is designed to estimate the in-hospital mortality risk for children prior to receiving respiratory extracorporeal membrane oxygenation (ECMO) support. METHODS: This study used data from an international registry of patients aged 29 days to less than 18 years who received ECMO support from 2009 to 2014. We divided the registry into development and validation datasets by calendar date. Candidate variables were selected for model inclusion if the variable independently changed the mortality risk by at least 2 % in a Bayesian logistic regression model with in-hospital mortality as the outcome. We characterized the model's ability to discriminate mortality with the area under curve (AUC) of the receiver operating characteristic. RESULTS: From 2009 to 2014, 2458 non-neonatal children received ECMO for respiratory support, with a mortality rate of 39.8 %. The development dataset contained 1611 children receiving ECMO support from 2009 to 2012. The model included the following variables: pre-ECMO pH, pre-ECMO arterial partial pressure of carbon dioxide, hours of intubation prior to ECMO support, hours of admission at ECMO center prior to ECMO support, ventilator type, mean airway pressure, pre-ECMO use of milrinone, and a diagnosis of pertussis, asthma, bronchiolitis, or malignancy. The validation dataset included 438 children receiving ECMO support from 2013 to 2014. The Ped-RESCUERS model from the development dataset had an AUC of 0.690, and the validation dataset had an AUC of 0.634. CONCLUSIONS: Ped-RESCUERS provides a novel measure of pre-ECMO mortality risk. Future studies should seek external validation and improved discrimination of this mortality prediction tool.

Outcome of Adult Respiratory Failure Patients Receiving Prolonged (≥14 Days) ECMO.

OBJECTIVE: To examine the outcomes of prolonged (≥14 days) extracorporeal membrane oxygenation (P-ECMO) for adult severe respiratory failure and to assess characteristics associated with survival. BACKGROUND: The use of ECMO for treatment of severe respiratory adult patients is associated with overall survival rates of 50% to 70% with median ECMO duration of 10 days. No prior multi-institutional studies have examined outcomes of P-ECMO for severe respiratory failure. METHODS: Data on all adult (≥18 years) patients who required P-ECMO for severe respiratory failure from 1989 to 2013 were extracted from the Extracorporeal Life Support Organization international multi-institutional registry. We examined outcomes over 23 years and compared the 2 more recent time periods of 1989 to 2006 versus 2007 to 2013. RESULTS: Up to 974 patients, mean age 40.2 (18-83) years, had ECMO duration of mean 25.2 days/median 21.0 days (range: 14-208 days). Venovenous ECMO support was most common (venovenous: 79.5%, venoarterial: 9.9%). Reason for ECMO discontinuation included native lung recovery (54%), organ failure (23.7%), family request (6.7%), hemorrhage (2.7%), and diagnosis incompatible with life (5.6%). Forty patients (4.1%) underwent lung transplant with 50% postoperative in-hospital mortality. Increased prevalence of P-ECMO was noted with 72% (701/974) of all cases reported since 2008. Survival to hospital discharge was 45.4% (443/974) and did not vary with ECMO duration. Multivariate logistic regression analysis confirmed that P-ECMO patients 2007 to 2013 had a lower risk of death [odds ratio (OR): 0.650; 95% confidence interval (CI), 0.454-0.929; P = 0.010] compared with 1989 to 2006. Factors independently associated with survival were younger age (OR: 0.983; 95% CI, 0.974-0.993; P < 0.001) and lower PaCO2 (OR, 0.991; 95% CI, 0.986-0.996; P < 0.001). CONCLUSIONS: Prolonged ECMO use for adult respiratory failure was associated with a lower (45.4%) hospital survival rate, compared with prior reported survival rates of short duration ECMO. Prolonged ECMO survival significantly increased in recent years, and increasing ECMO duration did not alter the survival fraction in the 1989 to 2013 study cohort. Although P-ECMO survival rates are less than short ECMO runs, P-ECMO support is justified.

The Effect of Ex Situ Perfusion in a Swine Limb Vascularized Composite Tissue Allograft on Survival up to 24 Hours.

PURPOSE: To test the potential for the ex situ limb perfusion system to prolong limb allograft survival up to 24 hours. METHODS: We used 20 swine for the study. In group 1 (control), 4 limbs were perfused with heparin solution and preserved at 4°C for 6 hours. In group 2, 4 limbs were perfused with autologous blood at 27°C to 32°C for 24 hours. In both groups, limbs were transplanted orthotopically to recipients and monitored for 12 hours. In addition to perfusion parameters, we recorded perfusate gases and electrolytes (pH, pCO2, pO2, O2 saturation, Na, K, Cl, Ca, HCO3, glucose, and lactate) and obtained functional electrostimulation hourly throughout the experiment. Histology samples were obtained for TUNEL staining and single-muscle fiber contractility testing. RESULTS: In both groups, hemodynamic variables of circulation remained stable throughout the experiment. Neuromuscular electrical stimulation remained intact until the end of reperfusion in group 2 vs no response in group 1. In group 2, a gradual increase in lactate levels during pump perfusion returned to normal after transplantation. Compared with the contralateral limb in group 2, single-muscle fiber contractility testing showed no significant difference at the end of the experiment. CONCLUSIONS: We demonstrated extended limb survival up to 24 hours using normothermic pulsatile perfusion and autologous blood. CLINICAL RELEVANCE: Successful prolongation of limb survival using ex situ perfusion methods provides with more time for revascularization of an extremity.

Ex Situ Limb Perfusion System to Extend Vascularized Composite Tissue Allograft Survival in Swine.

BACKGROUND: Organ perfusion systems have successfully been applied in solid organ transplantations. Their use in limb transplantation and replantation has not been widely investigated. In this study, we tested the potential for ex situ perfusion system to prolong limb allograft viability in a swine forelimb amputation/replantation model. METHODS: Fourteen swine were used. In group 1 (n = 4), we perfused 4 amputated limbs for 12 hours using warm (27 °C-32 °C) autologous blood. Group 2 (n = 3) served as a cold preservation control group, preserving limbs for 6 hours at 4 °C. All limbs were transplanted into healthy swine (n = 7) and observed for another 12 hours. Hemodynamic variables of circulation, as well as perfusate gases and electrolytes (pH, pCO2, pO2, O2 saturation, Na(+), K(+), Cl(-), Ca(2+), HCO3(-), glucose, lactate) were measured. Muscle samples were used to measure single-muscle fiber contractility. RESULTS: In the control group, no microcirculation was observed after 6 hours of cold storage. In the pump perfusion group, all limbs displayed a gradual increase in lactate levels (P < 0.05) during ex situ perfusion that returned to normal after transplantation and reperfusion (P = 0.05). The pH and potassium remained stable throughout the experiment. Single-muscle fiber contractility testing showed near normal contractility at the end of the reperfusion period (P > 0.05). Limb weight did not increase significantly between the end of pump perfusion and reperfusion (P > 0.05). CONCLUSIONS: We demonstrated the potential to preserve limb allograft using ex vivo circulation. This approach promises to extend the narrow time frame for revascularization of procured extremities in limb transplantation.

Two decades' experience with interfacility transport on extracorporeal membrane oxygenation.

BACKGROUND: Interfacility transport of patients on extracorporeal membrane oxygenation (ECMO) has been performed in large numbers at only a few programs. Limited data are available on outcomes after ECMO transport to justify expanding or discontinuing these programs. METHODS: This was a retrospective review of a 20-year, single-institution experience with interhospital ECMO transport as well as a systematic review of reports of transfers of patients on ECMO. Results of both were compared with historical data from the international registry of the Extracorporeal Life Support Organization (ELSO). RESULTS: Between 1990 and 2012, ECMO was used to facilitate transport of 221 patients to our institution, and 135 (62%) survived to discharge. Review of an additional 27 case series describing ECMO transport of 643 patients showed an overall survival of 61%. After stratifying by age and primary indication for ECMO, survival of transported patients was not significantly different compared with all ECMO patients in the ELSO registry, with the exception of pediatric patients treated for respiratory failure (transported patients in this category had higher survival than those in the ELSO registry). CONCLUSIONS: Interfacility transport on ECMO is feasible and can be accomplished safely in the critically ill. Survival of transported patients is comparable to age-matched and treatment-matched ECMO patients at large.