Deoxyribonuclease I Alleviates Septic Liver Injury in a Rat Model Supported by Venoarterial Extracorporeal Membrane Oxygenation

Sepsis is an unusual systemic reaction with high mortality and secondary septic liver injury is proposed to be the major cause of mortality. Extracorporeal membrane oxygenation (ECMO) can enhance terminal organ perfusion by elevating circulatory support which is used in severe sepsis patients. However, the interaction of blood components with the biomaterials of the extracorporeal membrane elicits a systemic inflammatory response. Besides, inflammation and apoptosis are the main mediators in the pathophysiology of septic liver injury. Therefore, we investigated the protective effect of Deoxyribonuclease I (DNase I) against septic liver injury supported by ECMO in rats. Sepsis was induced by lipopolysaccharide (LPS) and 24 hours after the administration, the rats were treated with ECMO. Then blood samples and liver tissues were collected. DNase I significantly attenuated the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and significantly decreased hepatic levels of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome, myeloperoxidase (MPO), downstream inflammatory factor interleukin-1β (IL-1β) and interleukin-18 (IL-18), and improved neutrophil infiltration. Additionally, DNase I significantly reduced the expression of apoptosis key protein and terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL)-labeled apoptotic hepatocytes. In summary, our findings demonstrated that DNase I alleviates liver injury in ECMO-supported septic rats by reducing the inflammatory and apoptotic responses.

The Story of ECMO

Extracorporeal Circulation in Neonatal Respiratory Failure: A Prospective Randomized Study. By RH Bartlett, DW Roloff, RG Cornell, AF Andrews, PW Dillon, JB Zwischenberger. Pediatrics 1985; 76:479-87. Extracorporeal membrane oxygenation (ECMO) is the use of mechanical devices to replace cardiac and pulmonary function in critical care. In the 1960s, laboratory research showed that extracorporeal circulation could be maintained for days using a membrane oxygenator. In the 1970s, the first clinical trials showed that ECMO could sustain life in severe cardiac and pulmonary failure for days or weeks, leading to organ recovery. From 1980 to 2000, ECMO became standard practice for neonatal and pediatric respiratory and cardiac failure. The critical clinical trial was a prospective randomized trial of ECMO in newborn respiratory failure, published in 1985. This is the classic article reviewed in this publication. This was the first use of a randomized, adaptive design trial to minimize the potential ethical dilemma inherent to clinical trials in which the endpoint is death. Other randomized trials followed, and ECMO is now standard practice for severe respiratory and cardiac failure in all age groups.

Survival of Infants With Severe Congenital Kidney Disease After ECMO and Kidney Support Therapy

Congenital kidney failure not only affects the homeostatic functions of the kidney, but also affects neonatal respiratory integrity. Until recently, extracorporeal membrane oxygenation (ECMO) support was not used in this population because the need for ECMO clearly established nonviability. Since 2016, 31 neonates have been admitted to the NICU at Children's of Alabama with congenital kidney failure. Five patients were placed on ECMO for severe respiratory distress unresponsive to conventional interventions. We evaluated neonates with congenital kidney failure and pulmonary hypoplasia/hypertension refractory to conventional therapies who received ECMO support within the first 9 postnatal days. We describe the pre and postnatal diagnoses, ECMO course details, dialysis modalities, complications, procedures, and long-term outcomes of these patients. All 5 patients received kidney support therapy by postnatal day 7. Diagnoses included posterior urethral valves, bilateral renal dysplasia, and autosomal recessive polycystic kidney disease. Gestational age ranged from 35.6 to 37.1 weeks. Birth weight ranged from 2740 to 3140 g. Days on ECMO ranged from 4 to 23. Four survived and are living today. Pulmonary hypertension resolved in surviving patients. Three surviving patients require no oxygen support, and 1 patient requires nocturnal oxygen. Three survivors received a kidney transplant, and 1 awaits transplant evaluation. Patients with congenital kidney failure with severe pulmonary hypoplasia/pulmonary hypertension no longer warrant a reflexive assignment of nonviability. Meticulous ECMO, respiratory, nutritional, and kidney support therapies may achieve a favorable long-term outcome. Further investigation of strategies for optimal outcome is needed.

Prediction of In-Hospital Mortality for Ischemic Cardiogenic Shock Requiring Venoarterial Extracorporeal Membrane Oxygenation

BACKGROUND

Clinical outcome of ischemic cardiogenic shock (CS) requiring extracorporeal membrane oxygenation is highly variable, necessitating appropriate assessment of prognosis. However, a systemic predictive model estimating the mortality of refractory ischemic CS is lacking. The PRECISE (Prediction of In-Hospital Mortality for Patients With Refractory Ischemic Cardiogenic Shock Requiring Veno-Arterial Extracorporeal Membrane Oxygenation Support) score was developed to predict the prognosis of refractory ischemic CS due to acute myocardial infarction.

METHODS AND RESULTS

Data were obtained from the multicenter CS registry RESCUE (Retrospective and Prospective Observational Study to Investigate Clinical Outcomes and Efficacy of Left Ventricular Assist Device for Korean Patients With Cardiogenic Shock) that consists of 322 patients with acute myocardial infarction complicated by refractory ischemic CS requiring extracorporeal membrane oxygenation support. Fifteen parameters were selected to assess in-hospital mortality. The developed model was validated internally and externally using an independent external cohort (n=138). Among 322 patients, 138 (42.9%) survived postdischarge. Fifteen predictors were included for model development: age, diastolic blood pressure, hypertension, chronic kidney disease, peak lactic acid, serum creatinine, lowest left ventricular ejection fraction, vasoactive inotropic score, shock to extracorporeal membrane oxygenation insertion time, extracorporeal cardiopulmonary resuscitation, use of intra-aortic balloon pump, continuous renal replacement therapy, mechanical ventilator, successful coronary revascularization, and staged percutaneous coronary intervention. The PRECISE score yielded a high area under the receiver-operating characteristic curve (0.894 [95% CI, 0.860-0.927]). External validation and calibration resulted in competent sensitivity (area under the receiver-operating characteristic curve, 0.895 [95% CI, 0.853-0.930]).

CONCLUSIONS

The PRECISE score demonstrated high predictive performance and directly translates into the expected in-hospital mortality rate. The PRECISE score may be used to support clinical decision-making in ischemic CS (www.theprecisescore.com).

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02985008.

After ECMO Decannulation, Are Patients Thriving or Just Surviving?

The use of extracorporeal membrane oxygenation (ECMO) to support patients with cardiac arrest, cardiogenic shock, and acute respiratory distress syndrome is rising worldwide.1 While ECMO may save the lives of some of our sickest patients, the outlook of ECMO survivorship remains uncertain. Defining longer-term functional and neuropsychiatric outcomes in ECMO survivors is important for 3 reasons. First, critically ill patients are at high risk of experiencing postintensive care syndrome (PICS), defined as new physical, cognitive, or psychological impairments that present in survivors of critical illness after hospital discharge.2 PICS is associated with more severe illness and longer intensive care unit length of stay.3 Because ECMO is reserved for patients with refractory shock or hypoxia, patients treated with ECMO represent a severely ill patient population with prolonged length of stay, putting them at particularly high risk of developing PICS. Second, ECMO is associated with direct neurologic injury, including both macrohemorrhages and microhemorrhages, infarcts, and diffuse hypoxic-ischemic brain injury that likely contribute to long-term outcomes.4 Finally, ECMO is very expensive. A recent study determined that the average cost per admission for patients with COVID-19 placed on ECMO was nearly $850,000 more than those who received only mechanical ventilation.5 Understanding patient-centered outcomes will be an integral part of future cost-effectiveness analyses.

Impella Versus Intra-Aortic Balloon Pump in Patients With Cardiogenic Shock Treated With Venoarterial Extracorporeal Membrane Oxygenation: An Observational Study

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used for patients with cardiogenic shock. Although Impella or intra-aortic balloon pump (IABP) is frequently used for left ventricular unloading (LVU) during VA-ECMO treatment, there are limited data on comparative outcomes. We compared outcomes of Impella and IABP for LVU during VA-ECMO.

METHODS AND RESULTS

Using the Nationwide Readmissions Database between 2016 and 2020, we analyzed outcomes in 3 groups of patients with cardiogenic shock requiring VA-ECMO based on LVU strategies: extracorporeal membrane oxygenation (ECMO) only, ECMO with IABP, and ECMO with Impella. Of 15 980 patients on VA-ECMO, IABP and Impella were used in 19.4% and 16.4%, respectively. The proportion of patients receiving Impella significantly increased from 2016 to 2020 (6.5% versus 25.8%; P-trend<0.001). In-hospital mortality was higher with ECMO with Impella (54.8%) compared with ECMO only (50.4%) and ECMO with IABP (48.4%). After adjustment, ECMO with IABP versus ECMO only was associated with lower in-hospital mortality (adjusted odds ratio [aOR], 0.83; P=0.02). ECMO with Impella versus ECMO only had similar in-hospital mortality (aOR, 1.09; P=0.695) but was associated with more bleeding (aOR, 1.21; P=0.007) and more acute kidney injury requiring hemodialysis (aOR, 1.42; P<0.001). ECMO with Impella versus ECMO with IABP was associated with greater risk of acute kidney injury requiring hemodialysis (aOR, 1.49; P=0.002), higher in-hospital mortality (aOR, 1.32; P=0.001), and higher 40-day mortality (hazard ratio, 1.25; P<0.001).

CONCLUSIONS

In patients with cardiogenic shock on VA-ECMO, LVU with Impella, particularly with 2.5/CP, was not associated with improved survival at 40 days but was associated with increased adverse events compared with IABP. More data are needed to assess Impella platform-specific comparative outcomes of LVU.

Timing of Initiation of Extracorporeal Membrane Oxygenation Support and Outcomes Among Patients With Cardiogenic Shock

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (ECMO) provides full hemodynamic support for patients with cardiogenic shock, but optimal timing of ECMO initiation remains uncertain. We sought to determine whether earlier initiation of ECMO is associated with improved survival in cardiogenic shock.

METHODS AND RESULTS

We analyzed adult patients with cardiogenic shock who received venoarterial ECMO from the international Extracorporeal Life Support Organization (ELSO) registry from 2009 to 2019, excluding those cannulated following an operation. Multivariable logistic regression evaluated the association between time from admission to ECMO initiation and in-hospital death. Among 8619 patients (median, 56.7 [range, 44.8-65.6] years; 33.5% women), the median duration from admission to ECMO initiation was 14 (5-32) hours. Patients who had ECMO initiated within 24 hours (n=5882 [68.2%]) differed from those who had ECMO initiated after 24 hours, with younger age, more preceding cardiac arrest, and worse acidosis. After multivariable adjustment, patients with ECMO initiated >24 hours after admission had higher risk of in-hospital death (adjusted odds ratio, 1.20 [95% CI, 1.06-1.36]; P=0.004). Each 12-hour increase in the time from admission to ECMO initiation was incrementally associated with higher adjusted in-hospital mortality rate (adjusted odds ratio, 1.06 [95% CI, 1.03-1.10]; P<0.001). The association between longer time to ECMO and worse outcomes appeared stronger in patients with lower shock severity.

CONCLUSIONS

Longer delays from admission to ECMO initiation were associated with higher a mortality rate in a large-scale, international registry. Our analysis supports optimization of door-to-support time and the avoidance of inappropriately delayed ECMO initiation.

Asymmetric Triple-Functional Janus Membrane for Blood Oxygenation

The oxygenation membrane, a core material of extracorporeal membrane oxygenation (ECMO), is facing challenges in balancing anti-plasma leakage, gas exchange efficiency, and hemocompatibility. Here, inspired by the asymmetric structural features of alveolus pulmonalis, a novel triple-functional membrane for blood oxygenation with a Janus architecture is proposed, which is composed of a hydrophobic polydimethylsiloxane (PDMS) layer to prevent plasma leakage, an ultrathin polyamide layer to enhance gas exchange efficiency with a CO2 :O2 permeance ratio of ≈10.7, and a hydrophilic polyzwitterionic layer to improve the hemocompatibility. During the simulated ECMO process, the Janus oxygenation membrane exhibits excellent performance in terms of thrombus formation and plasma leakage prevention, as well as adequate O2 transfer rate (17.8 mL min-1 m-2 ) and CO2 transfer rate (70.1 mL min-1 m-2 ), in comparison to the reported oxygenation membranes. This work presents novel concepts for the advancement of oxygenation membranes and demonstrates the application potential of the asymmetric triple-functional Janus oxygenation membrane in ECMO.