Venovenous Extracorporeal Membrane Oxygenation For Respiratory Failure Research Articles

The role of inflammation and antithrombin supplementation on thromboelastographic parameters during veno-venous ECMO for respiratory failure.

Extracorporeal membrane oxygenation (ECMO) may act as a driver or propagator of systemic inflammation. In turn, cytokine release can modify thromboelastographic (TEG) tests which are commonly used for anticoagulation monitoring. In this context, antithrombin (AT) supplementation might further modify TEG. This is a pre-specified sub-study of the "Randomized Controlled Trial of Antithrombin Supplementation During Extracorporeal Membrane Oxygenation" study (investigator-initiated, randomized, single-blind, two-arm trial) conducted in two Italian ECMO referral ICUs. Adult patients requiring vv-ECMO for respiratory failure and undergoing unfractioned heparin (UFH) administration were enrolled and randomized whether to receive AT supplementation. Plasma samples for cytokine assay (IL-8, IL-10, IL-6, IL-1β, TNF-α and Pro-ADM) and heparinase TEG were collected from every patient before ECMO start, 24h and 72h after ECMO start, before ECMO removal, and 7days after ECMO removal or upon ICU discharge whichever happened first. AT concentration, coagulation and clinical data were collected before ECMO start and at pre-fixed time points. Thirty-nine patients were enrolled (21 treatments, 18 controls). TEG-R had a weak-to-moderate positive correlation with IL-8, IL-6, IL-10 and TNF-α and a moderate positive correlation with Pro-ADM. TEG-ANG showed a weak negative correlation with IL-8, IL-6 and TNF-α, while TEG-MA negatively correlated with IL-8, TNF-α and Pro-ADM. AT supplementation seemed to modify the association between TEG-MA and IL-8, IL-10 and Pro-ADM; conversely, AT did not affect the relationship among TEG-R or TEG-ANG and the studied cytokines. High concentrations of systemic cytokines correlated with longer reaction times and decreased angle and amplitude at TEG, suggesting that an increase in inflammation is related with hypocoagulability as revealed by thromboelastography.

A.5 Neurovascular complications of veno-venous extracorporeal membrane oxygenation in critically ill COVID-19 patients

Background: Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is an invasive intervention for patients with respiratory failure associated with COVID-19. This meta-analysis aims to determine the incidence of neurovascular complications in COVID-19 patients requiring VV-ECMO. Methods: Systematic literature search of MEDLINE, Embase, PsycINFO, and Cochrane databases was performed to identify studies that reported neurovascular complications of adult COVID-19 patients on VV-ECMO for respiratory failure. Case series and reports were excluded. Studies with 95% or more of its patients on VV-ECMO were pooled for meta-analysis. Results: Eighteen studies (n=1968) were included for meta-analyses. In COVID-19 patients requiring VV-ECMO, the incidences of intracranial hemorrhage and ischemic stroke were 11% [95% CI, 8–15%] and 2% [95% CI, 1–3%], respectively. Intraparenchymal and subarachnoid hemorrhages accounted for 73% and 8% of all intracranial hemorrhages, respectively. The risk ratio of mortality in COVID-19 patients with neurovascular complications on VV-ECMO compared to patients without neurovascular complications was 2.24 [95% CI, 1.46–3.46]. Conclusions: COVID-19 patients requiring VV-ECMO have a higher incidence of intracranial hemorrhage compared to historical data in non-COVID-19 patients (11% vs. 8%), while the incidence of ischemic stroke is similar (2%) in both cohorts. COVID-19 patients with neurovascular complications on VV-ECMO are at an increased risk of death.

This Month in Anesthesiology

This Month in Anesthesiology

Hybrid and parallel extracorporeal membrane oxygenation circuits

Hybrid and parallel extracorporeal membrane oxygenation circuits

The Known Unknowns of Obesity and Extracorporeal Membrane Oxygenation.

The Known Unknowns of Obesity and Extracorporeal Membrane Oxygenation.

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.

Blood Transfusion Strategies in Patients Undergoing Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) is frequently associated with bleeding and coagulopathy complications, which may lead to the need for transfusion of multiple blood products. However, blood transfusions are known to increase morbidity and mortality, as well as hospital cost, in critically ill patients. In current practice, patients on ECMO receive a transfusion, on average, of 1-5 packed red blood cells (RBCs)/day, with platelet transfusion accounting for the largest portion of transfusion volume. Generally, adult patients require more transfusions than neonates or children, and patients receiving venovenous ECMO for respiratory failure tend to need smaller transfusion volumes compared to those receiving venoarterial ECMO for cardiac failure. Observation studies have reported that a higher transfusion volume was associated with increased mortality. To date, the evidence for transfusion in patients undergoing ECMO is limited; most knowledge on transfusion strategies was extrapolated from studies in critically ill patients. However, current data support a restrictive blood transfusion strategy for ECMO patients, and a low transfusion trigger seems to be safe and reasonable.

Early extracorporeal life support experiences in 2 tertiary pediatric intensive care units in Turkey.

Extracorporeal membrane oxygenation (ECMO) is a unique life-support modality offered to patients unresponsive to optimal medical therapy. The aim of this study was to evaluate early experiences with ECMO support in 2 tertiary Turkish pediatric intensive care units (PICUs). We retrospectively evaluated a total of 10 ECMO-supported patients between March 2012 and March 2013 in Marmara and Ege University Hospital PICUs. We reported data regarding demographics, laboratory and diagnostic information, and the clinical course of the patients. The study consisted of 6 males and 4 females from 5 months to 14 years of age (mean age: 0.5 ± 5.01 years) supported with ECMO. Out of the 10 patients, 8 were on venovenous ECMO for respiratory failure and 2 received venoarterial ECMO for cardiac failure. Mean ECMO and intensive care duration was 11.1 ± 7.3 days and 23.5 ± 17.8 days, respectively. Bleeding was the most common complication (60%). Forty percent of the patients were weaned from ECMO, among which 50% were discharged in good health without sequelae. Initial experiences build the learning curve of institutions, and our early results are encouraging. Giving time to heal to the right patient at the right time is the key to success.

Blood oxygenation and decarboxylation determinants during venovenous ECMO for respiratory failure in adults

This study was designed to optimize the latest generation venovenous (vv)-extracorporeal membrane oxygenation (ECMO)-circuit configuration and settings based on the evaluation of blood oxygenation and CO2 removal determinants in patients with severe acute respiratory distress syndrome (ARDS) on ultraprotective mechanical ventilation. Blood gases and hemodynamic parameters were evaluated after changing one of three ECMO settings, namely, circuit blood flow, FiO(2ECMO) (fraction of inspired oxygen in circuit), or sweep gas flow ventilating the membrane, while leaving the other two parameters at their maximum setting. Ten mechanically ventilated ARDS patients (mean age 44 ± 16 years; 6 males; mean hemoglobin 8.0 ± 1.8 g/dL) on ECMO for a mean of 9.0 ± 3.8 days) receiving femoro-jugular vv-ECMO were evaluated. vv-ECMO blood flow and FiO(2ECMO) determined arterial oxygenation. Decreasing the ECMO flow from its baseline maximum value (5.8 ± 0.8 L/min) to 40% less (2.4 ± 0.3 L/min) significantly decreased mean PaO2 (arterial oxygen tension; 88 ± 24 to 45 ± 9 mm Hg; p < 0.001) and SaO2 (oxygen saturation; 97 ± 2 to 82 ± 10%; p < 0.001). When the ECMO flow/cardiac output was >60%, SaO2 was always >90%. Alternatively, the rate of sweep gas flow through the membrane lung determined blood decarboxylation, while PaCO2 (arterial carbon dioxide tension) was unaffected when the ECMO blood flow and FiO(2ECMO) were reduced to <2.5 L/min and 40%, respectively. In three additional patients evaluated before and after red blood cell transfusion, O2 delivery increased after transfusion, allowing lower ECMO flows to reach adequate SaO2. For severe ARDS patients receiving femoro-jugular vv-ECMO, blood flow was the main determinant of arterial oxygenation, while CO2 elimination depended on sweep gas flow through the oxygenator. An ECMO flow/cardiac output >60% was constantly associated with adequate blood oxygenation and oxygen transport and delivery.

Systemic hypertension associated with venovenous extracorporeal membrane oxygenation for pediatric respiratory failure

Background/purpose Arterial hypertension (HTN) is common in neonates on venoarterial (VA) extracorporeal membrane oxygenation (ECMO), but HTN in pediatric venovenous (VV) ECMO has not been well described. The authors noted HTN in their VV ECMO experience and hypothesized that HTN was associated with fluid status, steroid use, and renal insufficiency. Methods Records of 50 patients receiving VV ECMO for respiratory failure were reviewed. HTN was defined as systolic blood pressure greater than 95th percentile for age for ≥1 hour, unresponsive to sedation/analgesia. Hypertensive index (HI) is defined as total hypertensive hours per total ECMO hours. Fluid status was estimated by a fluid index (FI = total fluid balance during ECMO per ECMO hours per weight). Results Forty-seven of 50 patients (94%) had HTN. Median HI was 0.21 (range, 0.01 to 1.0). Thirteen patients had renal insufficiency, 39 received steroids, and 23 received continuous venovenous hemofiltration (CVVH). There was no association between HI and FI, steroid use, or renal insufficiency. Thirty-three patients were treated for HTN, often requiring multiple agents. Bleeding complicated the course of 18 patients, and HI was significantly higher in those patients ( P = .03). HI was not different between survivors (37 of 39 with HTN) and nonsurvivors (10 of 11 with HTN). Conclusions Hypertension is a common complication associated with VV ECMO with unclear etiology. HTN was frequently difficult to control. This study emphasizes the need for the development of treatment protocols to decrease the incidence, severity, and associated morbidity. Improved insight into the etiology of HTN associated with pediatric VV ECMO, including evaluation of the renin-angiotensin system, would help guide therapy.

Successful Use of ECMO in Adults with Life-threatening Infections

Two cases of critically ill patients who received extracorporeal membrane oxygenation (ECMO) using different forms of circuitry and for different indications are presented. Both patients had life-threatening infections with septic shock and were not able to be supported by conventional means. The first patient had staphylococcal septicaemia and received venoarterial ECMO for circulatory failure. The second patient had psittacosis and received venovenous ECMO for respiratory failure. We discuss the expanding indications for this technology and the role it has to play in adult intensive care.