Triage of V-V ECMO referrals for COVID-19 respiratory failure.

BACKGROUND: As the pandemic progressed, the use of extracorporeal membrane oxygenation (ECMO) for COVID-19-related acute respiratory distress syndrome increased, and patient triage and transfer to ECMO centers became important to optimize patient outcomes. Our objectives are to identify predictors of patient transfer for veno-venous extracorporeal membrane oxygenation (V-V ECMO) evaluation as well as to describe the outcomes of accepted patients. METHODS: This is a single-center, retrospective analysis of V-V ECMO transfer requests for adult patients with known or suspected COVID-19 and respiratory failure from March 2020 until March 2021. Data were collected prospectively during the triage process for transfer requests as part of clinical patient care at our institution. RESULTS: Of 341 referred patients, 112 (33%) were accepted for transfer to our facility, whereas 229 (67%) patients were declined for transfer. The Classification and Regression Tree analysis showed that patients' high pressure during airway pressure release ventilation (APRV) and age were the variables most significantly associated with the decision to accept or decline patients for transfer. CONCLUSIONS: Our triage process enabled one-third of referred patients to be transferred for evaluation, with nearly 70% of those patients ultimately receiving ECMO support. High ventilator settings on APRV and young age were associated with acceptance for transfer. Accepted patients also had a higher incidence of adjunctive therapies (proning and paralysis) prior to transfer request, less cardiac or renal dysfunction, and a shorter duration of mechanical ventilation. Further research is warranted to investigate the outcomes of nontransferred patients.

Cannula associated deep vein thromboses in COVID-19 patients supported with VV ECMO.

BACKGROUND: VV ECMO is increasingly used as a rescue strategy for hypercarbic and hypoxic respiratory failure refractory to conventional management, and more than 14,000 patients with COVID-19 related respiratory failure have been supported with VV ECMO to date. One of the known complications of VV ECMO support is the development of cannula-associated deep vein thromboses (CaDVT). The purpose of this study was to identify the incidence of CaDVT in COVID-19 patients supported with VV ECMO as compared to non-COVID-19 patients. We hypothesized that due to the hypercoagulable state and longer duration of VV ECMO support required for patients with COVID-19, a higher incidence of CaDVT would be observed in these patients. METHODS: This is a single center, retrospective observational study. About 291 non-trauma adult patients who were cannulated for VV ECMO and managed at our institution from January 1, 2014 to January 10, 2022 were included. The primary outcome was the presence of CaDVT 24 h after decannulation in COVID-19 versus non-COVID-19 patients. Our secondary outcome was continued presence of DVT on follow up imaging. CaDVT were defined as venous thrombi detected at prior cannulation sites. RESULTS: Both groups had a high incidence of CaDVT. There was no significant difference in the incidence of CaDVT in COVID-19 patients compared to non-COVID-19 patients (95% vs 88%, p = 0.13). Patients with COVID-19 had an increased incidence of persistent CaDVT on repeat imaging (78% vs 56%, p = 0.03). CONCLUSION: Given the high number of post-decannulation CaDVT in both groups, routine screening should be a part of post ECMO care in both populations. Repeat venous duplex ultrasound should be performed to assess for the need for ongoing treatment given the high incidence of CaDVT that persisted on repeat duplex scans.

Spinal Cord Infarction With Prolonged Femoral Venoarterial Extracorporeal Membrane Oxygenation.

OBJECTIVES: There have been sporadic reports of ischemic spinal cord injury (SCI) during venoarterial extracorporeal membrane oxygenation (VA-ECMO) support. The authors observed a troubling pattern of this catastrophic complication and evaluated the potential mechanisms of SCI related to ECMO. DESIGN: This study was a case series. SETTING: This study was performed at a single institution in a University setting. PARTICIPANTS: Patients requiring prolonged VA-ECMO were included. INTERVENTIONS: No interventions were done. This was an observational study. MEASUREMENTS AND MAIN RESULTS: Four hypotheses of etiology were considered: (1) hypercoagulable state/thromboembolism, (2) regional hypoxia/hypocarbia, (3) hyperperfusion and spinal cord edema, and (4) mechanical coverage of spinal arteries. The SCI involved the lower thoracic (T7-T12 level) spinal cord to the cauda equina in all patients. Seven out of 132 (5.3%) patients with prolonged VA-ECMO support developed SCI. The median time from ECMO cannulation to SCI was 7 (range: 6-17) days.There was no evidence of embolic SCI or extended regional hypoxia or hypocarbia. A unilateral, internal iliac artery was covered by the arterial cannula in 6/7 86%) patients, but flow into the internal iliac was demonstrated on imaging in all available patients. The median total flow (ECMO + intrinsic cardiac output) was 8.5 L/min (LPM), and indexed flow was 4.1 LPM/m2. The median central venous oxygen saturation was 88%, and intracranial pressure was measured at 30 mmHg in one patient, suggestive of hyperperfusion and spinal cord edema. CONCLUSIONS: An SCI is a serious complication of extended peripheral VA-ECMO support. Its etiology remains uncertain, but the authors' preliminary data suggested that spinal cord edema from hyperperfusion or venous congestion could contribute.

COVID-19 outcomes of venovenous extracorporeal membrane oxygenation for acute respiratory failure vs historical cohort of non-COVID-19 viral infections.

INTRODUCTION: Veno-venous extracorporeal membrane oxygenation (VV ECMO) has become a support modality for patients with acute respiratory failure refractory to standard therapies. VV ECMO has been increasingly used during the current COVID-19 pandemic for patients with refractory respiratory failure. The object of this study was to evaluate the outcomes of VV ECMO in patients with COVID-19 compared to patients with non-COVID-19 viral infections. METHODS: We retrospectively reviewed all patients supported with VV ECMO between 8/2014 and 8/2020 whose etiology of illness was a viral pulmonary infection. The primary outcome of this study was to evaluate in-hospital mortality. The secondary outcomes included length of ECMO course, ventilator duration, hospital length of stay, incidence of adverse events through ECMO course. RESULTS: Eighty-nine patients were included (35 COVID-19 vs 54 non-COVID-19). Forty (74%) of the non-COVID-19 patients had influenza virus. Prior to cannulation, COVID-19 patients had longer ventilator duration (3 vs 1 day, p = .003), higher PaCO2 (64 vs 53 mmHg, p = .012), and white blood cell count (14 vs 9 ×103/µL, p = .004). Overall in-hospital mortality was 33.7% (n = 30). COVID-19 patients had a higher mortality (49% vs. 24%, p = .017) when compared to non-COVID-19 patients. COVID-19 survivors had longer median time on ECMO than non-COVID-19 survivors (24.4 vs 16.5 days p = .03) but had a similar hospital length of stay (HLOS) (41 vs 48 Extracorporeal Membrane Oxygenationdays p = .33). CONCLUSION: COVID-19 patients supported with VV ECMO have a higher mortality than non-COVID-19 patients. While COVID-19 survivors had significantly longer VV ECMO runs than non-COVID-19 survivors, HLOS was similar. This data add to a growing body of literature supporting the use of ECMO for potentially reversible causes of respiratory failure.

A descriptive evaluation of causes of death in venovenous extracorporeal membrane oxygenation.

Veno-venous extracorporeal membrane oxygenation (VV ECMO) has become an important support modality for patients with acute respiratory failure refractory to optimal medical therapy, such as low tidal volume mechanical ventilator support, early paralytic infusion, and early prone positioning. The objective of this cohort study was to investigate the causes and timing of in-hospital mortality in patients on VV ECMO. All patients, excluding trauma and bridge to lung transplant, admitted 8/2014-6/2019 to a specialty ICU for VV ECMO were reviewed. Two hundred twenty-five patients were included. In-hospital mortality was 24.4% (n = 55). Most non-survivors (46/55, 84%) died prior to lung recovery and decannulation from VV ECMO. Most common cause of death (COD) for patients who died on VV ECMO was removal of life sustaining therapy (LST) in setting of multisystem organ failure (MSOF) (n = 24). Nine patients died a median of 9 days [6, 11] after decannulation. Most common COD in these patients was palliative withdrawal of LST due to poor prognosis (n = 3). Non-survivors were older and had worse predictive mortality scores than survivors. We found that death in patients supported with VV ECMO in our study most often occurs prior to decannulation and lung recovery. This study demonstrated that the most common cause of death in patients supported with VV ECMO was removal of LST due MSOF. Acute hemorrhage (systemic or intracranial) was not found to be a common cause of death in our patient population.

Neurologic Outcomes After Extracorporeal Cardiopulmonary Resuscitation: Recent Experience at a Single High-Volume Center.

Extracorporeal cardiopulmonary resuscitation (ECPR)-veno-arterial extracorporeal membrane oxygenation (ECMO) for refractory cardiac arrest-has grown rapidly, but its widespread adoption has been limited by frequent neurologic complications. With individual centers developing best practices, utilization may be increasing with an uncertain effect on outcomes. This study describes the recent ECPR experience at the University of Maryland Medical Center from 2016 through 2018, with attention to neurologic outcomes and predictors thereof. The primary outcome was dichotomized Cerebral Performance Category (≤2) at hospital discharge; secondary outcomes included rates of specific neurologic complications. From 429 ECMO runs over 3 years, 57 ECPR patients were identified, representing an increase in ECPR utilization compared with 41 cases over the previous 6 years. Fifty-two (91%) suffered in-hospital cardiac arrest, and 36 (63%) had an initial nonshockable rhythm. Median low-flow time was 31 minutes. Overall, 26 (46%) survived hospitalization and 23 (88% of survivors, 40% overall) had a favorable discharge outcome. Factors independently associated with good neurologic outcome included lower peak lactate, initial shockable rhythm, and higher initial ECMO mean arterial pressure. Neurologic complications occurred in 18 patients (32%), including brain death in 6 (11%), hypoxic-ischemic brain injury in 11 (19%), ischemic stroke in 6 (11%), intracerebral hemorrhage in 1 (2%), and seizure in 4 (7%). We conclude that good neurologic outcomes are possible for well-selected ECPR patients in a high-volume program with increasing utilization and evolving practices. Markers of adequate peri-resuscitation tissue perfusion were associated with better outcomes, suggesting their importance in neuroprognostication.

Association of Volume Status During Veno-Venous Extracorporeal Membrane Oxygenation with Outcome.

Fluid overload in acute respiratory distress syndrome is associated with increased mortality. The purpose of this study was to investigate the association of cumulative fluid balance (CFB) during the first 7 days of veno-venous extracorporeal membrane oxygenation (VV ECMO) and mortality. Adult patients on VV ECMO for greater than 168 hours, between November 2015 and October 2019, were included. CFB during the first 7 ECMO days was compared between survivors and nonsurvivors, and survival was analyzed using Kaplan-Meier analysis and cox proportional hazards modeling. One hundred forty-six patients were included. Median age was 45 years [32, 55], respiratory ECMO survival prediction score was 3 [0, 5], and P/F ratio was 70 [55, 85]. CFB for ECMO days 1-3 was +2,350 cc [-540, 5,941], days 4-7 -3,070 cc [-6,545, 437], and days 1-7 -341 cc [-4,579, 5,290]. One hundred seventeen patients (80%) survived to hospital discharge. Survivors were younger (41 years [31, 53] vs. 53 years [45, 60], p < 0.001) and had a higher respiratory ECMO survival prediction score, (3 [1, 5] vs. 1.5 [-1, 3], p = 0.002). VV ECMO survivors had a significantly more negative CFB during the first 7 days of VV ECMO (-1,311 cc [-4,755, 4,217] vs. 3,617 cc [-2,764, 9,413], p = 0.02), and CFB was an independent predictor of 90 day mortality (HR = 1.07 [1.01, 1.14], p = 0.02). Further studies are needed to determine the causal relationship between fluid balance and survival during VV ECMO.

Intraoperative Management of Adult Patients on Extracorporeal Membrane Oxygenation: an Expert Consensus Statement From the Society of Cardiovascular Anesthesiologists-Part I, Technical Aspects of Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) is used to support patients with refractory cardiopulmonary failure. Given ECMO's increased use in adults and the fact that many ECMO patients are cared for by anesthesiologists, the Society of Cardiovascular Anesthesiologists ECMO working group created an expert consensus statement that is intended to help anesthesiologists manage adult ECMO patients who are cared for in the operating room. In the first part of this 2-part series, technical aspects of ECMO are discussed, and related expert consensus statements are provided.

Intraoperative Management of Adult Patients on Extracorporeal Membrane Oxygenation: An Expert Consensus Statement From the Society of Cardiovascular Anesthesiologists-Part I, Technical Aspects of Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) is used to support patients with refractory cardiopulmonary failure. Given ECMO's increased use in adults and the fact that many ECMO patients are cared for by anesthesiologists, the Society of Cardiovascular Anesthesiologists ECMO working group created an expert consensus statement that is intended to help anesthesiologists manage adult ECMO patients who are cared for in the operating room. In the first part of this 2-part series, technical aspects of ECMO are discussed, and related expert consensus statements are provided.

Intraoperative Management of Adult Patients on Extracorporeal Membrane Oxygenation: An Expert Consensus Statement From the Society of Cardiovascular Anesthesiologists-Part II, Intraoperative Management and Troubleshooting.

In the second part of the Society of Cardiovascular Anesthesiologists Extracorporeal Membrane Oxygenation (ECMO) working group expert consensus statement, venoarterial (VA) and venovenous (VV) ECMO management and troubleshooting in the operating room are discussed. Expert consensus statements are provided about intraoperative monitoring, anesthetic drug dosing, and management of intraoperative problems in VA and VV ECMO patients.

A Dedicated Veno-Venous Extracorporeal Membrane Oxygenation Unit during a Respiratory Pandemic: Lessons Learned from COVID-19 Part I: System Planning and Care Teams.

BACKGROUND: The most critically ill patients with coronavirus disease 2019 (COVID-19) may require advanced support modalities, such as veno-venous extracorporeal membrane oxygenation (VV-ECMO). A systematic, methodical approach to a respiratory pandemic on a state and institutional level is critical. METHODS: We conducted retrospective review of our institutional response to the COVID-19 pandemic, focusing on the creation of a dedicated airlock biocontainment unit (BCU) to treat patients with refractory COVID-19 acute respiratory distress syndrome (CARDS). Data were collected through conversations with staff on varying levels in the BCU, those leading the effort to make the BCU and hospital incident command system, email communications regarding logistic changes being implemented, and a review of COVID-19 patient census at our institution from March through June 2020. RESULTS: Over 2100 patients were successfully admitted to system hospitals; 29% of these patients required critical care. The response to this respiratory pandemic augmented intensive care physician staffing, created a 70-member nursing team, and increased the extracorporeal membrane oxygenation (ECMO) capability by nearly 200%. During this time period, 40 COVID-19 patients on VV-ECMO were managed in the BCU. Challenges in an airlock unit included communication, scarcity of resources, double-bunking, and maintaining routine care. CONCLUSIONS: Preparing for a surge of critically ill patients during a pandemic can be a daunting task. The implementation of a coordinated, system-level approach can help with the allocation of resources as needed. Focusing on established strengths of hospitals within the system can guide triage based on individual patient needs. The management of ECMO patients is still a specialty care, and a systematic and hospital based approach requiring an ECMO team composed of multiple experienced individuals is paramount during a respiratory viral pandemic.

A Dedicated Veno-Venous Extracorporeal Membrane Oxygenation Unit during a Respiratory Pandemic: Lessons Learned from COVID-19 Part II: Clinical Management.

(1) Background: COVID-19 acute respiratory distress syndrome (CARDS) has several distinctions from traditional acute respiratory distress syndrome (ARDS); however, patients with refractory respiratory failure may still benefit from veno-venous extracorporeal membrane oxygenation (VV-ECMO) support. We report our challenges caring for CARDS patients on VV-ECMO and alterations to traditional management strategies. (2) Methods: We conducted a retrospective review of our institutional strategies for managing patients with COVID-19 who required VV-ECMO in a dedicated airlock biocontainment unit (BCU), from March to June 2020. The data collected included the time course of admission, VV-ECMO run, ventilator length, hospital length of stay, and major events related to bleeding, such as pneumothorax and tracheostomy. The dispensation of sedation agents and trial therapies were obtained from institutional pharmacy tracking. A descriptive statistical analysis was performed. (3) Results: Forty COVID-19 patients on VV-ECMO were managed in the BCU during this period, from which 21 survived to discharge and 19 died. The criteria for ECMO initiation was altered for age, body mass index, and neurologic status/cardiac arrest. All cannulations were performed with a bedside ultrasound-guided percutaneous technique. Ventilator and ECMO management were routed in an ultra-lung protective approach, though varied based on clinical setting and provider experience. There was a high incidence of pneumothorax (n = 19). Thirty patients had bedside percutaneous tracheostomy, with more procedural-related bleeding complications than expected. A higher use of sedation was noted. The timing of decannulation was also altered, given the system constraints. A variety of trial therapies were utilized, and their effectiveness is yet to be determined. (4) Conclusions: Even in a high-volume ECMO center, there are challenges in caring for an expanded capacity of patients during a viral respiratory pandemic. Though institutional resources and expertise may vary, it is paramount to proceed with insightful planning, the recognition of challenges, and the dynamic application of lessons learned when facing a surge of critically ill patients.

Clinical Outcomes of Pregnant and Postpartum Extracorporeal Membrane Oxygenation Patients.

BACKGROUND: The use of extracorporeal membrane oxygenation (ECMO) as a rescue therapy for cardiopulmonary failure is expanding in critical care medicine. In this case series, we describe the clinical outcomes of 21 consecutive pregnant or postpartum patients that required venovenous (VV) or venoarterial (VA) ECMO. Our objective was to characterize maternal and fetal survival in peripartum ECMO and better understand ECMO-related complications that occur in this unique patient population. METHODS: Between January 2009 and June 2019, all pregnant and postpartum patients treated with ECMO for respiratory or circulatory failure at a single quaternary referral center were identified. For all patients, indications for ECMO, maternal and neonatal outcomes, details of ECMO support, and anticoagulation and bleeding complications were collected. RESULTS: Twenty-one obstetric patients were treated with ECMO over 10 years. Thirteen patients were treated with VV ECMO and 8 patients were treated with VA ECMO. Six patients were pregnant at the time of cannulation and 3 patients delivered while on ECMO; all 6 maternal and infant dyads survived to hospital discharge. The median gestational age at cannulation was 28 weeks (interquartile range [IQR], 24-31). In the postpartum cohort, ECMO initiation ranged from immediately after delivery up to 46 days postpartum. Fifteen women survived (72%). Major bleeding complications requiring surgical intervention were observed in 7 patients (33.3%). Two patients on VV ECMO required bilateral orthotopic lung transplantation and 1 patient on VA ECMO required orthotopic heart transplantation to wean from ECMO. CONCLUSIONS: Survival for mother and neonate are excellent with peripartum ECMO in a high-volume ECMO center. Neonatal and maternal survival was 100% when ECMO was used in the late second or early third trimester. Based on these results, ECMO remains an important treatment option for peripartum patients with cardiopulmonary failure.

A Retrospective Study of Infection in Patients Requiring Extracorporeal Membrane Oxygenation Support.

BACKGROUND: Healthcare-associated infections (HAIs) in critically ill patients are a serious public health problem. Extracorporeal membrane oxygenation (ECMO) has been used increasingly for patients with severe cardiac or respiratory failure, but it may increase HAI risk. The goal of our study was to characterize HAIs in ECMO patients at an ECMO referral center. METHODS: This institutional review board-approved study identified all consecutive adult ECMO patients admitted to the cardiac surgery intensive care unit (CSICU) between January 1, 2015, and December 31, 2017. Demographic data, diagnosis, ECMO cannulation technique, and survival were collected. Urinary tract infection, pneumonia, and bacteremia incidence during ECMO and within 3 months of decannulation were collected. Outcomes of patients with HAIs were compared with noninfected patients, the CSICU infection incidence, and overall Extracorporeal Life Support Organization survival data. RESULTS: There were 288 ECMO patients and 3396 CSICU admissions during this period. Survival was 72.3% for venoarterial ECMO, 85.3% for venovenous ECMO, and 57.1% for multimodality or veno-arteriovenous ECMO, with discharge survival of 60.2%, 72.0%, and 28.6%, respectively. Bacteremia incidence while cannulated was 6.8% for venoarterial ECMO and 9.3% for venovenous ECMO. Bacteremia occurred in 22 of 288 (7.6%) ECMO patients, compared with 48 of 3109 (1.5%) in non-ECMO CSICU patients, which was statistically significant (P < .002). Bacteremia and pneumonia were associated with decreased VA-ECMO survival, with prolonged overall requirements for ECMO support. CONCLUSIONS: Nosocomial ECMO infections are significantly higher than in other CSICU patients. Infection risk remains significant even after decannulation. Infection is associated with increased mortality and longer duration of ECMO support. Further efforts are needed to determine HAI reduction strategies in this high-risk patient population.

Von Willebrand Factor Concentrate Administration for Acquired Von Willebrand Syndrome- Related Bleeding During Adult Extracorporeal Membrane Oxygenation.

OBJECTIVE: To review the use of Von Willebrand Factor (VWF) concentrate for treatment of acquired Von Willebrand syndrome (VWS)-related bleeding in adult extracorporeal membrane oxygenation (ECMO) patients and determine if it was associated with improved VWF laboratory parameters. DESIGN: Retrospective observational cohort study. SETTING: Tertiary care academic medical center. PARTICIPANTS: Adult ECMO patients who received VWF concentrate for treatment of acquired VWS- related bleeding. INTERVENTIONS: None, observational study. MEASUREMENTS AND MAIN RESULTS: Ten adult ECMO patients received VWF concentrate for treatment of bleeding with evidence of acquired VWS over a 15-month period. Six patients were on veno-arterial ECMO and 4 were on veno-venous ECMO. The most common site of bleeding was airway or tracheal bleeding. The mean dose of VWF concentrate was 41 IU/kg. Mean VWF antigen was 263 ± 93 IU/dL before treatment and 394 ± 54 after treatment. Mean ristocetin cofactor activity was 127 ± 47 IU/dL before treatment and 240 ± 33 after treatment. The mean VWF ristocetin cofactor activity antigen ratio increased from 0.52 ± 0.14 before treatment to 0.62 ± 0.04 after treatment. Four of 10 patients had complete resolution of their bleeding within 24 hours, and 6 of 10 had complete resolution of their bleeding within 2- to- 4 days. There were 3 patients who had thrombotic events potentially related to VWF concentrate administration. No patient had an arterial thrombosis, stroke, or myocardial infarction. CONCLUSIONS: VWF concentrate administration increases VWF function in adult ECMO patients, but also may be associated with increased thrombotic risk. Larger studies are needed to determine VWF concentrate's safety, efficacy, and optimal dosing in adult ECMO patients.

Platelet factor-4 concentration in adult veno-arterial ECMO patients.

BACKGROUND: Heparin induced thrombocytopenia (HIT) is reported at a variable rate in extracorporeal membrane oxygenation (ECMO) patients. A critical factor impacting platelet factor-4 (PF4)-heparin antibody formation is plasma PF4 concentration. We hypothesized that PF4 concentration would be increased during veno-arterial (VA) ECMO. METHODS: Plasma PF4 concentration was measured during the first 5 ECMO days in 20 VA ECMO patients and 10 control plasma samples. PF4-heparin ratios were estimated using an assumed heparin concentration of 0.4 IU/mL. This correlates with an activated partial thromboplastin time of 60 to 80 seconds, which is the anticoagulation target in our center. RESULTS: Twenty VA ECMO patients were enrolled, 10 of which had pulmonary embolism. Median PF4 concentration was 0.03 µg/mL [0.01, 0.13] in control plasma. Median PF4 concentration was 0.21 µg/mL [0.12, 0.34] on ECMO day 1 or 2, 0.16 µg/mL [0.09, 0.25] on ECMO day 3, and 0.12 µg/mL [0.09, 0.22] on ECMO day 5. Estimated median PF4-heparin ratios were 0.04, 0.03, and 0.02 respectively. Two patients (10%) developed HIT that was confirmed by serotonin release assay. PF4 concentration did not differ significantly in these patients compared to non-HIT patients (p = 0.37). No patient had an estimated PF4-heparin ratio between 0.7 and 1.4, which is the reported optimal range for PF4-heparin antibody formation. CONCLUSION: Our data suggest that PF4 concentration is mildly elevated during VA ECMO compared to control plasma. Estimated PF4-heparin ratios were not optimal for HIT antibody formation. These data support epidemiologic studies where HIT incidence is low during VA ECMO.

High-efficiency, high-flux in-line hemofiltration using a high blood flow extracorporeal circuit.

The ability of current renal replacement therapy modalities to achieve rapid solute removal is limited by membrane surface area and blood flow rate. Extracorporeal membrane oxygenation offers high blood flow and hemodynamic support that may be harnessed to overcome limitations in traditional renal replacement therapy. Using an extracorporeal membrane oxygenation circuit, we describe a high blood flow, high-efficiency hemofiltration technique using in-line hemofilters (hemoconcentrators) and standard replacement fluid to enhance solute clearance. Using this approach and a total of 5 L of replacement volume per treatment, creatinine (Cr) clearances of 8.3 L/hour and 11.2 L/hour using one and two hemoconcentrators, respectively, were achieved. With use of a high blood flow rate of up to 5 L/min, this hemofiltration technique can potentially offer clearance of 30 times that of continuous renal replacement therapy and of 6 times that of hemodialysis which may expand the ability to remove substances traditionally not considered removable via existing extracorporeal therapies.

Pilot study evaluating a non-titrating, weight-based anticoagulation scheme for patients on veno-venous extracorporeal membrane oxygenation.

OBJECTIVE: There is no universally accepted algorithm for anticoagulation in patients on veno-venous extracorporeal membrane oxygenation. The purpose of this pilot study was to compare a non-titrating weight-based heparin infusion to that of a standard titration algorithm. METHODS: We performed a prospective randomized non-blinded study of patients: Arm 1-standard practice of titrating heparin to activated partial thromboplastin times goal of 45-55 seconds, and Arm 2-a non-titrating weight-based (10 units/kg/h) infusion. Primary outcome was need for oxygenator/circuit changes. Secondary outcomes included differences in hemolysis and bleeding episodes. Descriptive statistics were performed for the continuous data, and primary and secondary outcomes were compared using Fisher's exact test as appropriate. RESULTS: Six patients were randomized to Arm 1 and four to Arm 2. There was no difference in age, pH, PaO2/FiO2 ratio, peak inspiratory pressure, positive end expiratory pressure, mean airway pressure at time of cannulation, time on extracorporeal membrane oxygenation, or survival to hospital discharge in the two arms. Arm 1 had a statistically higher median activated partial thromboplastin times (48 (43, 52) vs 38 (35, 42), p < 0.008) and lower LDH (808 units/L (727, 1112) vs 940 units/L (809, 1137), p = 0.02) than Arm 2. There was no difference in plasma hemoglobin (4.3 (2.5, 8.7) vs 4.3 (3.0, 7.3), p = 0.65) between the two arms. There was no difference in mean oxygenator/circuit change, transfused packed red blood cell, or documented bleeding complications per patient in each arm (p = 0.56, 0.43, 0.77, respectively). CONCLUSION: In this pilot study, a non-titrating, weight-based heparin infusion appears safe and as effective in preventing veno-venous extracorporeal membrane oxygenation circuit thrombotic complications as compared to a titration algorithm. Larger studies are needed to confirm these preliminary findings.