Project description:BackgroundVenovenous extracorporeal membrane oxygenation (ECMO) is increasingly being used for acute respiratory distress syndrome and as a bridge to lung transplantation. After initiation of venovenous ECMO, systemic anticoagulation therapy is traditionally administered and can cause bleeding diathesis. Here, we investigated whether venovenous ECMO can be administered without continuous systemic anticoagulation administration for patients with acute respiratory distress syndrome.MethodsThis is a retrospective review of an institutional ECMO database. We included consecutive patients from January 2015 through February 2019. Overall, 38 patients received low levels of continuous systemic anticoagulation (AC+) whereas the subsequent 36 patients received standard venous thromboprophylaxis (AC-). Published Extracorporeal Life Support Organization guidelines were used for the definition of outcomes and complications.ResultsOverall, survival was not different between the two groups (P = .58). However, patients in the AC+ group had higher rates of gastrointestinal bleeding (28.9%, vs AC- group 5.6%; P < .001). The events per patient-day of gastrointestinal bleeding was 0.00025 in the AC- group and 0.00064 in the AC+ group (P < .001). In addition, oxygenator dysfunction was increased in the AC+ group (28.9% and 0.00067 events per patient-day, vs AC- 11.1% and 0.00062 events per patient-day; P = .02). Furthermore, the AC+ group received more transfusions: packed red blood cells, AC+ group 94.7% vs AC- group 55.5% (P < .001); fresh frozen plasma, AC+ 60.5% vs AC- 16.6% (P = .001); and platelets, AC+ 84.2% vs AC- 27.7% (P < .001). There was no circuit thrombosis in either groups throughout the duration of ECMO support.ConclusionsOur results suggest that venovenous ECMO can be safely administered without continuous systemic anticoagulation therapy. This approach may be associated with reduced bleeding diathesis and need for blood transfusions.
Project description:Venovenous extracorporeal membrane oxygenation is a treatment for acute respiratory distress syndrome. Femoro-atrial cannulation means blood is drained from the inferior vena cava and returned to the superior vena cava; the opposite is termed atrio-femoral. Clinical data comparing these two methods is scarce and conflicting. Using computational fluid dynamics, we aim to compare atrio-femoral and femoro-atrial cannulation to assess the impact on recirculation fraction, under ideal conditions and several clinical scenarios. Using a patient-averaged model of the venae cavae and right atrium, commercially-available cannulae were positioned in each configuration. Additionally, occlusion of the femoro-atrial drainage cannula side-holes with/without reduced inferior vena cava inflow (0-75%) and retraction of the atrio-femoral drainage cannula were modelled. Large-eddy simulations were run for 2-6L/min circuit flow, obtaining time-averaged flow data. The model showed good agreement with clinical atrio-femoral recirculation data. Under ideal conditions, atrio-femoral yielded 13.5% higher recirculation than femoro-atrial across all circuit flow rates. Atrio-femoral right atrium flow patterns resembled normal physiology with a single large vortex. Femoro-atrial cannulation resulted in multiple vortices and increased turbulent kinetic energy at > 3L/min circuit flow. Occluding femoro-atrial drainage cannula side-holes and reducing inferior vena cava inflow increased mean recirculation by 11% and 32%, respectively. Retracting the atrio-femoral drainage cannula did not affect recirculation. These results suggest that, depending on drainage issues, either atrio-femoral or femoro-atrial cannulation may be preferrable. Rather than cannula tip proximity, the supply of available venous blood at the drainage site appears to be the strongest factor affecting recirculation.
Project description:BACKGROUND:Nosocomial infections occurring during extracorporeal membrane oxygenation (ECMO) support have already been reported, but few studied infections directly related to ECMO devices. This study aims to evaluate the rate of both colonisations and infections related to ECMO devices at the time of ECMO removal. RESULTS:We included all consecutive adult patients treated with venovenous ECMO (VV-ECMO) for at least 48 h during a 34-month study. At the time of ECMO removal, blood cultures, swab cultures on insertion cannula site and intravascular cannula extremity cultures were systematically performed. Each ECMO device was classified according to the infectious status into three groups: (1) uninfected/uncolonised ECMO device, (2) ECMO device colonisation and (3) ECMO device infection. Ninety-nine patients underwent 103 VV-ECMO, representing 1472 ECMO days. The ECMO device infection rate was 9.7% (10 events), including 7 ECMO device-related bloodstream infections (6.8%). The ECMO device colonisation rate was 32% (33 events). No difference was observed between the three groups, regarding days of mechanical ventilation, ICU length of stay, ICU mortality and in-hospital mortality. We observed a longer ECMO duration in the ECMO device colonisation group as compared to the uninfected/uncolonised ECMO device group [12 (9-20 days) vs. 5 days (5-16 days), respectively, p < 0.05]. CONCLUSIONS:At the time of ECMO removal, systematic blood culture and intravascular extremity cannula culture may help to diagnose ECMO device-related infection. We reported a quite low infection rate related to ECMO device. Further studies are needed to evaluate the benefits of systematic strategies of cannula culture at the time of ECMO removal.
Project description:No major study has been performed on the conversion from venovenous (VV) to venoarterial (VA) extracorporeal membrane oxygenation (ECMO) in adults. This single-center retrospective cohort study aimed to investigate the incidence, indication, and outcome in patients who converted from VV to VA ECMO. All adult patients (≥18 years) who commenced VV ECMO at our center between 2005 and 2018 were screened. Of 219 VV ECMO patients, 21% (n = 46) were converted to VA ECMO. The indications for conversion were right ventricular failure (RVF) (65%), cardiogenic shock (26%), and other (9%). In the converted patients, there was a significant increase in Sequential Organ Failure Assessment (SOFA) scores between admission 12 (9-13) and conversion 15 (13-17, p < 0.001). Compared to non-converted patients, converted patients also had a higher mortality rate (62% vs. 16%, p < 0.001) and a lower admission Respiratory Extracorporeal Membrane Oxygenation Survival Prediction (RESP) score (p < 0.001). Outcomes were especially unfavorable in those converted due to RVF. These results indicate that VA ECMO, as opposed to VV ECMO, should be considered as the first mode of choice in patients with respiratory failure and signs of circulatory impairment, especially in those with impaired RV function. For the remaining patients, Pre-admission RESP score, daily echocardiography, and SOFA score trajectories may help in the early identification of those where conversion from VV to VA ECMO is warranted. Multi-centric studies are warranted to validate these findings.
Project description:BackgroundA life-threatening complication of coronavirus disease 2019 (COVID-19) is acute respiratory distress syndrome (ARDS) refractory to conventional management. Venovenous (VV) extracorporeal membrane oxygenation (ECMO) (VV-ECMO) is used to support patients with ARDS in whom conventional management fails. Scoring systems to predict mortality in VV-ECMO remain unvalidated in COVID-19 ARDS. This report describes a large single-center experience with VV-ECMO in COVID-19 and assesses the utility of standard risk calculators.MethodsA retrospective review of a prospective database of all patients with COVID-19 who underwent VV-ECMO cannulation between March 15 and June 27, 2020 at a single academic center was performed. Demographic, clinical, and ECMO characteristics were collected. The primary outcome was in-hospital mortality; survivor and nonsurvivor cohorts were compared by using univariate and bivariate analyses.ResultsForty patients who had COVID-19 and underwent ECMO were identified. Of the 33 patients (82.5%) in whom ECMO had been discontinued at the time of analysis, 18 patients (54.5%) survived to hospital discharge, and 15 (45.5%) died during ECMO. Nonsurvivors presented with a statistically significant higher Prediction of Survival on ECMO Therapy (PRESET)-Score (mean ± SD, 8.33 ± 0.8 vs 6.17 ± 1.8; P = .001). The PRESET score demonstrated accurate mortality prediction. All patients with a PRESET-Score of 6 or lowers survived, and a score of 7 or higher was associated with a dramatic increase in mortality.ConclusionsThese results suggest that favorable outcomes are possible in patients with COVID-19 who undergo ECMO at high-volume centers. This study demonstrated an association between the PRESET-Score and survival in patients with COVID-19 who underwent VV-ECMO. Standard risk calculators may aid in appropriate selection of patients with COVID-19 ARDS for ECMO.
Project description:BackgroundExtracorporeal membrane oxygenation (ECMO) serves as a rescue therapy when systemic hypoxia persists despite conventional care for severe acute respiratory distress syndrome (ARDS). Due to the extracorporeal gas exchange, the p aO2/F iO2 ratio cannot be used as the primary marker for disease severity and progression. Therefore, we performed a propensity score-matched analysis to identify other potential predictors of outcomes in patients supported by ECMO therapy.ResultsBetween December 2014 and May 2018, 105 patients underwent venovenous ECMO in our institution. From these patients, we identified 28 who died during ECMO therapy and assigned 28 control patients using propensity score matching based on the following criteria: age, ARDS severity, and SAPSII score at admission. A statistical evaluation of the patient characteristics, intensive care data, morbidities, respiratory system variables, and outcomes was performed. The baseline patient characteristics did not differ between groups and ECMO was placed on day 1 in all patients. The analyzed variables of respiratory mechanics, such as the plateau pressure, positive end-expiratory pressure, and tidal volume, did not differ between groups. The driving pressure before ECMO was equal between the nonsurvivors and the controls. Twelve hours after initiation of ECMO therapy, the driving pressure decreased by 40.8% in the survivors but by only 20.1% in the nonsurvivors.ConclusionsWe report that very early driving pressure changes can serve as an indicator of disease severity and predict patient survival following ECMO therapy.
Project description:When determining extracorporeal oxygen transfer (V ML O 2 ) during venovenous extracorporeal membrane oxygenation (VV ECMO) dissolved oxygen is often considered to play a subordinate role due to its poor solubility in blood plasma. This study was designed to assess the impact of dissolved oxygen on systemic oxygenation in patients with acute respiratory distress syndrome (ARDS) on VV ECMO support by differentiating between dissolved and hemoglobin-bound extracorporeal oxygen transfer. We calculated both extracorporeal oxygen transfer based on blood gas analysis using the measuring energy expenditure in extracorporeal lung support patients (MEEP) protocol and measured oxygen uptake by the native lung with indirect calorimetry. Over 20% of V ML O 2 and over 10% of overall oxygen uptake (VO 2 total ) were realized as dissolved oxygen. The transfer of dissolved oxygen mainly depended on ECMO blood flow (BF ML ). In patients with severely impaired lung function dissolved oxygen accounted for up to 28% of VO 2 total . A clinically relevant amount of oxygen is transferred as physically dissolved fraction, which therefore needs to be considered when determining membrane lung function, manage ECMO settings or guiding the weaning procedure.