Post-Cardiac Arrest Care in Adult Patients After Extracorporeal Cardiopulmonary Resuscitation.

OBJECTIVES: Extracorporeal cardiopulmonary resuscitation (ECPR) serves as a lifesaving intervention for patients experiencing refractory cardiac arrest. With its expanding usage, there is a burgeoning focus on improving patient outcomes through optimal management in the acute phase after cannulation. This review explores systematic post-cardiac arrest management strategies, associated complications, and prognostication in ECPR patients. DATA SOURCES: A PubMed search from inception to 2023 using search terms such as post-cardiac arrest care, ICU management, prognostication, and outcomes in adult ECPR patients was conducted. STUDY SELECTION: Selection includes original research, review articles, and guidelines. DATA EXTRACTION: Information from relevant publications was reviewed, consolidated, and formulated into a narrative review. DATA SYNTHESIS: We found limited data and no established clinical guidelines for post-cardiac arrest care after ECPR. In contrast to non-ECPR patients where systematic post-cardiac arrest care is shown to improve the outcomes, there is no high-quality data on this topic after ECPR. This review outlines a systematic approach, albeit limited, for ECPR care, focusing on airway/breathing and circulation as well as critical aspects of ICU care, including analgesia/sedation, mechanical ventilation, early oxygen/C o2 , and temperature goals, nutrition, fluid, imaging, and neuromonitoring strategy. We summarize common on-extracorporeal membrane oxygenation complications and the complex nature of prognostication and withdrawal of life-sustaining therapy in ECPR. Given conflicting outcomes in ECPR randomized controlled trials focused on pre-cannulation care, a better understanding of hemodynamic, neurologic, and metabolic abnormalities and early management goals may be necessary to improve their outcomes. CONCLUSIONS: Effective post-cardiac arrest care during the acute phase of ECPR is paramount in optimizing patient outcomes. However, a dearth of evidence to guide specific management strategies remains, indicating the necessity for future research in this field.

Characteristics and Outcomes of Prolonged Venoarterial Extracorporeal Membrane Oxygenation After Cardiac Surgery: The Post-Cardiotomy Extracorporeal Life Support (PELS-1) Cohort Study.

OBJECTIVES: Most post-cardiotomy (PC) extracorporeal membrane oxygenation (ECMO) runs last less than 7 days. Studies on the outcomes of longer runs have provided conflicting results. This study investigates patient characteristics and short- and long-term outcomes in relation to PC ECMO duration, with a focus on prolonged (> 7 d) ECMO. DESIGN: Retrospective observational cohort study. SETTING: Thirty-four centers from 16 countries between January 2000 and December 2020. PATIENTS: Adults requiring post PC ECMO between 2000 and 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Characteristics, in-hospital, and post-discharge outcomes were compared among patients categorized by ECMO duration. Survivors and nonsurvivors were compared in the subgroup of patients with ECMO duration greater than 7 days. The primary outcome was in-hospital mortality. Two thousand twenty-one patients were included who required PC ECMO for 0-3 days (n = 649 [32.1%]), 4-7 days (n = 776 [38.3%]), 8-10 days (n = 263 [13.0%]), and greater than 10 days (n = 333 [16.5%]). There were no major differences in the investigated preoperative and procedural characteristics among ECMO duration groups. However, the longer ECMO duration category was associated with multiple complications including bleeding, acute kidney injury, arrhythmias, and sepsis. Hospital mortality followed a U-shape curve, with lowest mortality in patients with ECMO duration of 4-7 days (n = 394, 50.8%) and highest in patients with greater than 10 days ECMO support (n = 242, 72.7%). There was no significant difference in post-discharge survival between ECMO duration groups. In patients with ECMO duration greater than 7 days, age, comorbidities, valvular diseases, and complex procedures were associated with nonsurvival. CONCLUSIONS: Nearly 30% of PC ECMO patients were supported for greater than 7 days. In-hospital mortality increased after 7 days of support, especially in patients undergoing valvular and complex surgery, or who had complications, although the long-term post-discharge prognosis was comparable to PC ECMO patients with shorter support duration.

Point-of-Care Bedside Brain Magnetic Resonance Imaging Is Safe in Extracorporeal Membrane Oxygenation Patients With Swan Ganz Catheters: A Phantom Experiment and Single Center Experience.

INTRODUCTION: More than 1.2 million pulmonary artery catheters (PACs) are used in cardiac patients per annum within the United States. However, it is contraindicated in traditional 1.5 and 3T magnetic resonance imaging (MRI) scans. We aimed to test preclinical and clinical safety of using this imaging modality given the potential utility of needing it in the clinical setting. METHODS: We conducted two phantom experiments to ensure that the electromagnetic field power deposition associated with bare and jacketed PACs was safe and within the acceptable limit established by the Food and Drug Administration. The primary end points were the safety and feasibility of performing Point-of-Care (POC) MRI without imaging-related adverse events. We performed a preclinical computational electromagnetic simulation and evaluated these findings in nine patients with PACs on veno-arterial extracorporeal membrane oxygenation. RESULTS: The phantom experiments showed that the baseline point specific absorption rate through the head averaged 0.4 W/kg. In both the bare and jacketed catheters, the highest net specific absorption rates were at the neck entry point and tip but were negligible and unlikely to cause any heat-related tissue or catheter damage. In nine patients (median age 66, interquartile range 42-72 y) with veno-arterial extracorporeal membrane oxygenation due to cardiogenic shock and PACs placed for close hemodynamic monitoring, POC MRI was safe and feasible with good diagnostic imaging quality. CONCLUSIONS: Adult ECMO patients with PACs can safely undergo point-of-care low-field (64 mT) brain MRI within a reasonable timeframe in an intensive care unit setting to assess for acute brain injury that might otherwise be missed with conventional head computed tomography.

Incidence, risk factors, and outcomes of postoperative stroke in combined heart-lung transplantation: A retrospective cohort study of the UNOS registry.

Stroke is a well-characterized complication of isolated heart and lung transplantation, but has not been described in combined heart-lung transplantation (HLTx). We retrospectively reviewed national U.S. data to describe the incidence, risk factors, and impact of postoperative stroke in HLTx recipients. Of 871 heart-lung recipients between 1994-2022, 35 (4.0%) experienced stroke, and the incidence increased over time, trending toward significance (p-trend = .07). After adjustment, extracorporeal membrane oxygenation (ECMO) (Adjusted odds ratio [aOR] = 2.63, 95%CI = [1.13-6.11]) and pre-transplant implantable defibrillator (aOR = 2.86, 95%CI = [1.20-6.81]) were independent risk factors for stroke. Postoperative stroke is common and is increasing in an era where organ allocation is driven by mechanical circulatory support (MCS) bridging.

Post-cardiotomy extracorporeal life support: A cohort of cannulation in the general ward.

OBJECTIVES: Post-cardiotomy extracorporeal life support (ECLS) cannulation might occur in a general post-operative ward due to emergent conditions. Its characteristics have been poorly reported and investigated This study investigates the characteristics and outcomes of adult patients receiving ECLS cannulation in a general post-operative cardiac ward. METHODS: The Post-cardiotomy Extracorporeal Life Support (PELS) is a retrospective (2000-2020), multicenter (34 centers), observational study including adult patients who required ECLS for post-cardiotomy shock. This PELS sub-analysis analyzed patients´ characteristics, in-hospital outcomes, and long-term survival in patients cannulated for veno-arterial ECLS in the general ward, and further compared in-hospital survivors and non-survivors. RESULTS: The PELS study included 2058 patients of whom 39 (1.9%) were cannulated in the general ward. Most patients underwent isolated coronary bypass grafting (CABG, n = 15, 38.5%) or isolated non-CABG operations (n = 20, 51.3%). The main indications to initiate ECLS included cardiac arrest (n = 17, 44.7%) and cardiogenic shock (n = 14, 35.9%). ECLS cannulation occurred after a median time of 4 (2-7) days post-operatively. Most patients' courses were complicated by acute kidney injury (n = 23, 59%), arrhythmias (n = 19, 48.7%), and postoperative bleeding (n = 20, 51.3%). In-hospital mortality was 84.6% (n = 33) with persistent heart failure (n = 11, 28.2%) as the most common cause of death. No peculiar differences were observed between in-hospital survivors and nonsurvivors. CONCLUSIONS: This study demonstrates that ECLS cannulation due to post-cardiotomy emergent adverse events in the general ward is rare, mainly occurring in preoperative low-risk patients and after a postoperative cardiac arrest. High complication rates and low in-hospital survival require further investigations to identify patients at risk for such a complication, optimize resources, enhance intervention, and improve outcomes.

Machine Learning from Veno-Venous Extracorporeal Membrane Oxygenation Identifies Factors Associated with Neurological Outcomes.

BACKGROUND: Neurological complications are common in patients receiving veno-venous extracorporeal membrane oxygenation (VV-ECMO) support. We used machine learning (ML) algorithms to identify predictors for neurological outcomes for these patients. METHODS: All demographic, clinical, and circuit-related variables were extracted for adults with VV-ECMO support at a tertiary care center from 2016 to 2022. The primary outcome was good neurological outcome (GNO) at discharge defined as a modified Rankin Scale of 0-3. RESULTS: Of 99 total VV-ECMO patients (median age = 48 years; 65% male), 37% had a GNO. The best performing ML model achieved an area under the receiver operating characteristic curve of 0.87. Feature importance analysis identified down-trending gas/sweep/blender flow, FiO2, and pump speed as the most salient features for predicting GNO. CONCLUSION: Utilizing pre- as well as post-initiation variables, ML identified on-ECMO physiologic and pulmonary conditions that best predicted neurological outcomes.

Characterizing the Racial Discrepancy in Hypoxemia Detection in Venovenous Extracorporeal Membrane Oxygenation: An Extracorporeal Life Support Organization Registry Analysis.

PURPOSE: Skin pigmentation influences peripheral oxygen saturation (SpO2) compared to arterial saturation of oxygen (SaO2). Occult hypoxemia (SaO2 ≤ 88% with SpO2 ≥ 92%) is associated with increased in-hospital mortality in venovenous-extracorporeal membrane oxygenation (VV-ECMO) patients. We hypothesized VV-ECMO cannulation, in addition to race/ethnicity, accentuates the SpO2-SaO2 discrepancy due to significant hemolysis. METHODS: Adults (≥ 18 years) supported with VV-ECMO with concurrently measured SpO2 and SaO2 measurements from over 500 centers in the Extracorporeal Life Support Organization Registry (1/2018-5/2023) were included. Multivariable logistic regressions were performed to examine whether race/ethnicity was associated with occult hypoxemia in pre-ECMO and on-ECMO SpO2-SaO2 calculations. RESULTS: Of 13,171 VV-ECMO patients, there were 7772 (59%) White, 2114 (16%) Hispanic, 1777 (14%) Black, and 1508 (11%) Asian patients. The frequency of on-ECMO occult hypoxemia was 2.0% (N = 233). Occult hypoxemia was more common in Black and Hispanic patients versus White patients (3.1% versus 1.7%, P < 0.001 and 2.5% versus 1.7%, P = 0.025, respectively). In multivariable logistic regression, Black patients were at higher risk of pre-ECMO occult hypoxemia versus White patients (adjusted odds ratio [aOR] = 1.55, 95% confidence interval [CI] = 1.18-2.02, P = 0.001). For on-ECMO occult hypoxemia, Black patients (aOR = 1.79, 95% CI = 1.16-2.75, P = 0.008) and Hispanic patients (aOR = 1.71, 95% CI = 1.15-2.55, P = 0.008) had higher risk versus White patients. Higher pump flow rates (aOR = 1.29, 95% CI = 1.08-1.55, P = 0.005) and on-ECMO 24-h lactate (aOR = 1.06, 95% CI = 1.03-1.10, P < 0.001) significantly increased the risk of on-ECMO occult hypoxemia. CONCLUSION: SaO2 should be carefully monitored if using SpO2 during ECMO support for Black and Hispanic patients especially for those with high pump flow and lactate values at risk for occult hypoxemia.

Temporary Mechanical Circulatory Support after Cardiac Surgery.

Postcardiotomy shock in the cardiac surgical patient is a highly morbid condition characterized by profound myocardial impairment and decreased systemic perfusion inadequate to meet end-organ metabolic demand. Postcardiotomy shock is associated with significant morbidity and mortality. Poor outcomes motivate the increased use of mechanical circulatory support (MCS) to restore perfusion in an effort to prevent multiorgan injury and improve patient survival. Despite growing acceptance and adoption of MCS for postcardiotomy shock, criteria for initiation, clinical management, and future areas of clinical investigation remain a topic of ongoing debate. This article seeks to (1) define critical cardiac dysfunction in the patient after cardiotomy, (2) provide an overview of commonly used MCS devices, and (3) summarize the relevant clinical experience for various MCS devices available in the literature, with additional recognition for the role of MCS as a part of a modified approach to the cardiac arrest algorithm in the cardiac surgical patient.

Continuous Monitoring of Cerebral Autoregulation in Adults Supported by Extracorporeal Membrane Oxygenation.

BACKGROUND: Impaired cerebral autoregulation (CA) is one of several proposed mechanisms of acute brain injury in patients supported by extracorporeal membrane oxygenation (ECMO). The primary aim of this study was to determine the feasibility of continuous CA monitoring in adult ECMO patients. Our secondary aims were to describe changes in cerebral oximetry index (COx) and other metrics of CA over time and in relation to functional neurologic outcomes. METHODS: This is a single-center prospective observational study. We measured COx, a surrogate measurement of cerebral blood flow measured by near-infrared spectroscopy, which is an index of CA derived from the moving correlation between mean arterial pressure (MAP) and slow waves of regional cerebral oxygen saturation. A COx value that approaches 1 indicates impaired CA. Using COx, we determined the optimal MAP (MAPOPT) and lower and upper limits of autoregulation for individual patients. These measurements were examined in relation to modified Rankin Scale (mRS) scores. RESULTS: Fifteen patients (median age 57 years [interquartile range 47-69]) with 150 autoregulation measurements were included for analysis. Eleven were on veno-arterial ECMO (VA-ECMO), and four were on veno-venous ECMO (VV-ECMO). Mean COx was higher on postcannulation day 1 than on day 2 (0.2 vs. 0.09, p < 0.01), indicating improved CA over time. COx was higher in VA-ECMO patients than in VV-ECMO patients (0.12 vs. 0.06, p = 0.04). Median MAPOPT for the entire cohort was highly variable, ranging from 55 to 110 mm Hg. Patients with mRS scores 0-3 (good outcome) at 3 and 6 months spent less time outside MAPOPT compared with patients with mRS scores 4-6 (poor outcome) (74% vs. 82%, p = 0.01). The percentage of time when observed MAP was outside the limits of autoregulation was higher on postcannulation day 1 than on day 2 (18.2% vs. 3.3%, p < 0.01). CONCLUSIONS: In ECMO patients, it is feasible to monitor CA continuously at the bedside. CA improved over time, most significantly between postcannulation days 1 and 2. CA was more impaired in VA-ECMO patients than in VV-ECMO patients. Spending less time outside MAPOPT may be associated with achieving a good neurologic outcome.

Brain injury plasma biomarkers in patients on veno-arterial extracorporeal membrane oxygenation: A pilot prospective observational study.

INTRODUCTION: Early diagnosis of acute brain injury (ABI) is critical for patients on veno-arterial extracorporeal membrane oxygenation (V-A ECMO) to guide anticoagulation strategy; however, neurological assessment in ECMO is often limited by patient sedation. METHODS: In this pilot study of adults from June 2018 to May 2019, plasma samples of glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL), and tubulin associated unit (Tau) were collected daily after V-A ECMO cannulation and measured using a multiplex platform. Primary outcomes were occurrence of ABI, assessed clinically, and neurologic outcome, assessed by modified Rankin Scale (mRS). RESULTS: Of 20 consented patients (median age = 48.5°years; 55% female), 8 (40%) had ABI and 15 (75%) had unfavorable neurologic outcome at discharge. 10 (50%) patients were centrally cannulated. Median duration on ECMO was 4.5°days (IQR: 2.5-9.5). Peak GFAP, NFL, and Tau levels were higher in patients with ABI vs. without (AUC = 0.77; 0.85; 0.57, respectively) and in patients with unfavorable vs. favorable neurologic outcomes (AUC = 0.64; 0.59; 0.73, respectively). GFAP elevated first, NFL elevated to the highest degree, and Tau showed limited change regardless of ABI. CONCLUSION: Further studies are warranted to determine how plasma biomarkers may facilitate early detection of ABIs in V-A ECMO to assist timely clinical decision-making.

Hemorrhage, Disseminated Intravascular Coagulopathy, and Thrombosis Complications Among Critically Ill Patients with COVID-19: An International COVID-19 Critical Care Consortium Study.

OBJECTIVES: To determine the prevalence and outcomes associated with hemorrhage, disseminated intravascular coagulopathy, and thrombosis (HECTOR) complications in ICU patients with COVID-19. DESIGN: Prospective, observational study. SETTING: Two hundred twenty-nine ICUs across 32 countries. PATIENTS: Adult patients (≥ 16 yr) admitted to participating ICUs for severe COVID-19 from January 1, 2020, to December 31, 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: HECTOR complications occurred in 1,732 of 11,969 study eligible patients (14%). Acute thrombosis occurred in 1,249 patients (10%), including 712 (57%) with pulmonary embolism, 413 (33%) with myocardial ischemia, 93 (7.4%) with deep vein thrombosis, and 49 (3.9%) with ischemic strokes. Hemorrhagic complications were reported in 579 patients (4.8%), including 276 (48%) with gastrointestinal hemorrhage, 83 (14%) with hemorrhagic stroke, 77 (13%) with pulmonary hemorrhage, and 68 (12%) with hemorrhage associated with extracorporeal membrane oxygenation (ECMO) cannula site. Disseminated intravascular coagulation occurred in 11 patients (0.09%). Univariate analysis showed that diabetes, cardiac and kidney diseases, and ECMO use were risk factors for HECTOR. Among survivors, ICU stay was longer (median days 19 vs 12; p < 0.001) for patients with versus without HECTOR, but the hazard of ICU mortality was similar (hazard ratio [HR] 1.01; 95% CI 0.92-1.12; p = 0.784) overall, although this hazard was identified when non-ECMO patients were considered (HR 1.13; 95% CI 1.02-1.25; p = 0.015). Hemorrhagic complications were associated with an increased hazard of ICU mortality compared to patients without HECTOR complications (HR 1.26; 95% CI 1.09-1.45; p = 0.002), whereas thrombosis complications were associated with reduced hazard (HR 0.88; 95% CI 0.79-0.99, p = 0.03). CONCLUSIONS: HECTOR events are frequent complications of severe COVID-19 in ICU patients. Patients receiving ECMO are at particular risk of hemorrhagic complications. Hemorrhagic, but not thrombotic complications, are associated with increased ICU mortality.

Heart Allocation Change and Multiple Temporary Circulatory Support as Bridge-to-Bridge.

INTRODUCTION: We investigated how the 2018 Organ Procurement and Transplantation Network heart allocation policy change was associated with changes in characteristics and outcomes of candidates receiving multiple temporary mechanical circulatory support (mtMCS) devices. MATERIALS AND METHODS: We included adult heart transplant candidates listed October 2014-January 2018 and October 2018-January 2022 in the United Network of Organ Sharing dataset. Prepolicy and postpolicy mtMCS recipients were compared at listing, transplant, 90-days, and 1-year post-transplant. Time between first and second devices and time between first device and transplant were modeled via multivariable linear regression. Transplantation likelihood was modeled using competing risks analysis. RESULTS: Postpolicy, a higher proportion of transplant candidates received mtMCS (4% versus 1%, P < 0.001), and received their second device an adjusted 49 d sooner versus prepolicy (P = 0.001). Time to transplant was also an adjusted 35 d shorter postpolicy, with an 80% increased transplantation likelihood versus prepolicy (95% confidence interval: 1.6-1.9, P < 0.001). Postpolicy patients experienced reduced waitlist mortality (8% versus 14%, P = 0.04) with marked improvements in 90-day (93% versus 85%, P < 0.001) and 1-year (88% versus 70%, P = 0.01) post-transplant survival. CONCLUSIONS: Postpolicy mtMCS recipients are more likely to progress to transplantation sooner on the waitlist and their shorter waitlist course together with earlier change to a secondary device was associated with improved post-transplant survival versus prepolicy.

Epidemiology of ischemic stroke and hemorrhagic stroke in venoarterial extracorporeal membrane oxygenation.

BACKGROUND: While venoarterial extracorporeal membrane oxygenation (V-A ECMO) provides lifesaving support for cardiopulmonary failure, complications may increase mortality, with few studies focusing on ischemic/hemorrhagic stroke. We aimed to determine the trends and associations of stroke incidence and mortality, and their risk factors, including the effects of annual case volumes of ECMO centers. METHODS: Retrospective analysis was performed on the Extracorporeal Life Support Organization (ELSO) registry, including adult V-A ECMO patients from 534 international centers between 2012 and 2021, excluding extracorporeal cardiopulmonary resuscitation. Temporal trend analyses were performed for stroke incidence and mortality. Univariate testing, multivariable regression, and survival analysis were used to evaluate the associations of stroke, 90-day mortality, and impact of annual center volume. RESULTS: Of 33,041 patients, 20,297 had mortality data, and 12,327 were included in the logistic regression. Between 2012 and 2021, ischemic stroke incidence increased (p < 0.0001), hemorrhagic stroke incidence remained stable, and overall 90-day mortality declined (p < 0.0001). Higher 24-h PaO2 and greater decrease between pre-ECMO PaCO2 and post-cannulation 24-h PaCO2 were associated with greater ischemic stroke incidence, while annual case volume was not. Ischemic/hemorrhagic strokes were associated with increased 90-day mortality (both p < 0.0001), while higher annual case volume was associated with lower 90-day mortality (p = 0.001). Hazard of death was highest in the first several days of V-A ECMO. CONCLUSION: In V-A ECMO patients between 2012 and 2021, 90-day mortality decreased, while ischemic stroke incidence increased. ELSO centers with higher annual case volumes had lower mortality, but were not associated with ischemic/hemorrhagic stroke incidence. Both ischemic/hemorrhagic strokes were associated with increased mortality.

Heterogeneity in Clinical Practices for Post-Cardiotomy Extracorporeal Life Support: a Pilot Survey from the PELS-1 Multicenter Study.

BACKGROUND: High-quality evidence for post-cardiotomy extracorporeal life support (PC-ECLS) management is lacking. This study investigated the real-world PC-ECLS clinical practices. METHODS: This cross-sectional, multi-institutional, international pilot survey explored center organization, anticoagulation management, left ventricular unloading, distal limb perfusion, PC-ECLS monitoring and transfusions practices. Twenty-nine questions were distributed among 34 hospitals participating in the Post-cardiotomy Extra-Corporeal Life Support Study. RESULTS: Of the 32 centers [16 low-volume (50%); 16 high-volume (50%)] that responded, 16 (50%) had dedicated ECLS specialists. Twenty-six centers (81.3%) reported using additional mechanical circulatory supports. Anticoagulation practices were highly heterogeneous: 24 hospitals (75%) reported using patient's bleeding status as a guide, without a specific threshold in 54.2% of cases. Transfusion targets ranged 7-10 g/dL. Most centers used cardiac venting on a case-by-case basis (78.1%) and regular distal limb perfusion (84.4%). Nineteen (54.9%) centers reported dedicated monitoring protocols including daily echocardiography (87.5%), Swan-Ganz catheterization (40.6%), cerebral near-infrared spectroscopy (53.1%) and multimodal assessment of limb ischemia. Inspection of the circuit (71.9%), oxygenator pressure drop (68.8%), plasma free hemoglobin (75%), d-dimer (59.4%), lactate dehydrogenase (56.3%) and fibrinogen (46.9%) are used to diagnose hemolysis and thrombosis. CONCLUSIONS: This study shows remarkable heterogeneity in clinical practices for PC-ECLS management. More standardized protocols and better implementation of available evidence are recommended.

Lower Oxygen Tension and Intracranial Hemorrhage in Veno-venous Extracorporeal Membrane Oxygenation.

INTRODUCTION AND METHODS: We examined the relationship between 24-h pre- and post-cannulation arterial oxygen tension (PaO2) and arterial carbon dioxide tension (PaCO2) and subsequent acute brain injury (ABI) in patients receiving veno-venous extracorporeal membrane oxygenation (VV-ECMO) with granular arterial blood gas (ABG) data and institutional standardized neuromonitoring. RESULTS: Eighty-nine patients underwent VV-ECMO (median age = 50, 63% male). Twenty (22%) patients experienced ABI; intracranial hemorrhage (ICH) was the most common diagnosis (n = 14, 16%). Lower post-cannulation PaO2 levels were significantly associated with ICH (66 vs. 81 mmHg, p = 0.007) and a post-cannulation PaO2 level < 70 mmHg was more frequent in these patients (71% vs. 33%, p = 0.007). PaCO2 parameters were not associated with ABI. By multivariable logistic regression, hypoxemia post-cannulation increased the odds of ICH (OR = 5.06, 95% CI:1.41-18.17; p = 0.01). CONCLUSION: In summary, lower oxygen tension in the 24-h post-cannulation was associated with ICH development. The precise roles of peri-cannulation ABG changes deserve further investigation, as they may influence the management of VV-ECMO patients.

Impact of Preoperative Hematocrit, Body Mass Index, and Red Cell Mass on Allogeneic Blood Product Usage in Adult Cardiac Surgical Patients: Report From a Statewide Quality Initiative.

OBJECTIVE: The study aims were to evaluate current blood transfusion practice in cardiac surgical patients and to explore associations between preoperative anemia, body mass index (BMI), red blood cell (RBC) mass, and allogeneic transfusion. DESIGN: Multicenter retrospective study. SETTING: Academic and non-academic centers. PARTICIPANTS AND INTERVENTIONS: After Institutional Review Board approval, 26,499 patients who underwent coronary artery bypass grafting ± valve replacement/repair between 2011 and 2019 were included from the Maryland Cardiac Surgery Quality Initiative database. Patients were stratified into BMI categories (<25, 25 to <30, and ≥30 kg/m2), and a multivariable logistic regression model was fit to determine if preoperative hematocrit, BMI, and RBC mass were associated independently with allogeneic transfusion. RESULTS: Preoperative anemia was found in 55.4%, and any transfusion was administered to 49.3% of the entire cohort. Females and older patients had lower BMI and RBC mass. Increased RBC and cryoprecipitate transfusions occurred more frequently after surgery in the lower BMI group. After adjustments, increased transfusion was associated with a BMI <25 relative to a BMI ≥30 at an odds ratio (OR) of 1.26 (95% confidence interval [CI]: 1.08-1.39). For each 1% increase in preoperative hematocrit, transfusion was decreased by 9% (OR: 0.91; 95% CI: 0.90-0.92). For every 500 mL increase in RBC mass, there was a 43% reduction of transfusion (OR: 0.57; 95% CI: 0.55-0.58). CONCLUSIONS: Transfusion probability modeling based on calculated RBC mass eliminated sex differences in transfusion risk based on preoperative hematocrit, and may better delineate which patients may benefit from more rigorous perioperative blood conservation strategy.

What Factors Are Associated With Arterial Line-Related Limb Ischemia in Patients on Extracorporeal Membrane Oxygenation? A Single-Center Retrospective Cohort Study.

OBJECTIVES: The primary purpose of this study was to identify factors associated with the development of arterial line-related limb ischemia in patients on extracorporeal membrane oxygenation (ECMO). The authors also sought to characterize and report the outcomes of patients who developed arterial line-related limb ischemia. DESIGN: Retrospective cohort study. SETTING: A single academic tertiary referral ECMO center. PARTICIPANTS: Consecutive patients who were treated with ECMO over 6 years. INTERVENTIONS: Use of arterial line. MEASUREMENTS AND MAIN RESULTS: A total of 278 consecutive ECMO patients were included, with 19 (7%) patients developing arterial line-related limb ischemia during the ECMO run. Postcannulation Sequential Organ Failure Assessment (SOFA) (adjusted odds ratio [aOR] 1.20, 95% CI 1.08-1.32), Acute Physiology and Chronic Health Evaluation-II (aOR 0.84, 95% CI 0.74-0.95), and adjusted Vasopressor Dose Equivalence (aOR 1.03, 95% CI 1.01-1.05) scores were independently associated with the development of arterial line-associated limb ischemia. A SOFA score of ≥17 at the time of ECMO cannulation had an 80% sensitivity and 87% specificity for predicting arterial line-related limb ischemia. CONCLUSIONS: Arterial line-related limb ischemia is much more common in ECMO patients than in the typical intensive care unit setting. The SOFA score may be useful in identifying which patients may be at risk for arterial line-related limb ischemia. As this was a single-center retrospective study, these results are inherently exploratory, and prospective multicenter studies are necessary to validate these results.

Characterization of Cerebral Hemodynamics with TCD in Patients Undergoing VA-ECMO and VV-ECMO: a Prospective Observational Study.

BACKGROUND: Extracorporeal membrane oxygenation has a high risk of acute brain injury and resultant mortality. Transcranial Doppler characterizes cerebral hemodynamics in real time, but limited data exist on its interpretation in ECMO. Here, we report TCD mean flow velocity and pulsatility index in a large ECMO population. METHODS: This was a prospective cohort study at a tertiary care center. The patients were adults on venoarterial ECMO or venovenous ECMO undergoing TCD studies. RESULTS: A total of 135 patients underwent a total of 237 TCD studies while on VA-ECMO (n = 95, 70.3%) or VV-ECMO (n = 40, 29.6%). MFVs were captured reliably (approximately 90%) and were similar to a published healthy cohort in all vessels except the internal carotid artery. Presence of a recordable PI was strongly associated with ECMO mode (57% in VA vs. 95% in VV, p < 0.001). Absence of TCD pulsatility was associated with intraparenchymal hemorrhage (14.7 vs. 1.6%, p = 0.03) in VA-ECMO patients. CONCLUSIONS: Transcranial Doppler analysis in a single-center cohort of VA-ECMO and VV-ECMO patients demonstrates similar MFVs and PIs. Absence of PIs was associated with a higher frequency of intraparenchymal hemorrhage and a composite bleeding event. However, cautious interpretation and external validation is necessary for these findings with a multicenter study with a larger sample size.

Early Low Pulse Pressure in VA-ECMO Is Associated with Acute Brain Injury.

BACKGROUND: Pulse pressure is a dynamic marker of cardiovascular function and is often impaired in patients on venoarterial extracorporeal membrane oxygenation (VA-ECMO). Pulsatile blood flow also serves as a regulator of vascular endothelium, and continuous-flow mechanical circulatory support can lead to endothelial dysfunction. We explored the impact of early low pulse pressure on occurrence of acute brain injury (ABI) in VA-ECMO. METHODS: We conducted a retrospective analysis of adults with VA-ECMO at a tertiary care center between July 2016 and January 2021. Patients underwent standardized multimodal neuromonitoring throughout ECMO support. ABI included intracranial hemorrhage, ischemic stroke, hypoxic ischemic brain injury, cerebral edema, seizure, and brain death. Blood pressures were recorded every 15 min. Low pulse pressure was defined as a median pulse pressure < 20 mm Hg in the first 12 h of ECMO. Multivariable logistic regression was performed to investigate the association between pulse pressure and ABI. RESULTS: We analyzed 5138 blood pressure measurements from 123 (median age 63; 63% male) VA-ECMO patients (54% peripheral; 46% central cannulation), of whom 41 (33%) experienced ABI. Individual ABIs were as follows: ischemic stroke (n = 18, 15%), hypoxic ischemic brain injury (n = 14, 11%), seizure (n = 8, 7%), intracranial hemorrhage (n = 7, 6%), cerebral edema (n = 7, 6%), and brain death (n = 2, 2%). Fifty-eight (47%) patients had low pulse pressure. In a multivariable model adjusting for preselected covariates, including cannulation strategy (central vs. peripheral), lactate on ECMO day 1, and left ventricle venting strategy, low pulse pressure was independently associated with ABI (adjusted odds ratio 2.57, 95% confidence interval 1.05-6.24). In a model with the same covariates, every 10-mm Hg decrease in pulse pressure was associated with 31% increased odds of ABI (95% confidence interval 1.01-1.68). In a sensitivity analysis model adjusting for systolic pressure, pulse pressure remained significantly associated with ABI. CONCLUSIONS: Early low pulse pressure (< 20 mm Hg) was associated with ABI in VA-ECMO patients. Low pulse pressure may serve as a marker of ABI risk, which necessitates close neuromonitoring for early detection.

Challenges in determining death by neurologic criteria in extracorporeal membrane oxygenation - A single center experience.

INTRODUCTION: Apnea test (AT) in patients on extracorporeal membrane oxygenation (ECMO) support is challenging, leading to variation in determining death by neurologic criteria (DNC). We aim to describe the diagnostic criteria and barriers for DNC in adults on ECMO in a tertiary care center. METHODS: A retrospective review of a prospective observational standardized neuromonitoring study was conducted in adult VA- and VV-ECMO patients at a tertiary center from June 2016 to March 2022. Brain death was defined according to the 2010 American Academy of Neurology guidelines and following the 2020 World Brain Death Project recommendations for performing AT in ECMO patients. RESULTS: Eight (2.7%) ECMO patients (median age = 44 years, 75% male, 50% VA-ECMO) met criteria for DNC, six (75%) of whom were determined with AT. In the other two patients who did not undergo AT due to safety concerns, ancillary tests (transcranial doppler and electroencephalography) were consistent with DNC. An additional seven (2.3%) patients (median age = 55 years, 71% male, 86% VA-ECMO) were noted to have absent brainstem reflexes but failed to complete determination of DNC as they underwent withdrawal of life-sustaining treatment (WLST) before a full evaluation was completed. In these patients, AT was never performed, and ancillary tests were inconsistent with either neurological exam findings and/or neuroimaging supporting DNC, or with each other. CONCLUSION: AT was used safely and successfully in 6 of the 8 ECMO patients diagnosed with DNC and was always consistent with the neurological exam and imaging findings, as opposed to ancillary tests alone.