Antithrombin Levels and Heparin Responsiveness during Venoarterial Extracorporeal Membrane Oxygenation: A Prospective Single-center Cohort Study

BACKGROUND

Unfractionated heparin, administered during venoarterial extracorporeal membrane oxygenation to prevent thromboembolic events, largely depends on plasma antithrombin for its antithrombotic effects. Decreased heparin responsiveness seems frequent on extracorporeal membrane oxygenation; however, its association with acquired antithrombin deficiency is poorly understood. The objective of this study was to describe longitudinal changes in plasma antithrombin levels during extracorporeal membrane oxygenation support and evaluate the association between antithrombin levels and heparin responsiveness. The hypothesis was that extracorporeal membrane oxygenation support would be associated with acquired antithrombin deficiency and related decreased heparin responsiveness.

METHODS

Adults receiving venoarterial extracorporeal membrane oxygenation were prospectively included. All patients received continuous intravenous unfractionated heparin using a standardized protocol (target anti-Xa 0.3 to 0.5 IU/ml). For each patient, arterial blood was withdrawn into citrate-containing tubes at 11 time points (from hour 0 up to day 7). Anti-Xa (without dextran or antithrombin added) and antithrombin levels were measured. The primary outcome was the antithrombin plasma level. In the absence of consensus, antithrombin deficiency was defined as a time-weighted average of antithrombin less than or equal to 70%. Data regarding clinical management and heparin dosage were collected.

RESULTS

Fifty patients, including 42% postcardiotomy, were included between April 2020 and May 2021, with a total of 447 samples. Median extracorporeal membrane oxygenation duration was 7 (interquartile range, 4 to 12) days. Median antithrombin level was 48% (37 to 60%) at baseline. Antithrombin levels significantly increased throughout the follow-up. Time-weighted average of antithrombin levels was 63% (57 to 73%) and was less than or equal to 70% in 32 (64%) of patients. Overall, 45 (90%) patients had at least one antithrombin value less than 70%, and 35 (70%) had at least one antithrombin value less than 50%. Antithrombin levels were not significantly associated with heparin responsiveness evaluated by anti-Xa assay or heparin dosage.

CONCLUSIONS

Venoarterial extracorporeal membrane oxygenation support was associated with a moderate acquired antithrombin deficiency, mainly during the first 72 h, that did not correlate with heparin responsiveness.

EDITOR’S PERSPECTIVE

Predicting the mortality of patients with cardiogenic shock after coronary artery bypass grafting

INTRODUCTION

Cardiogenic shock (CS) is a critical condition and the leading cause of mortality after coronary artery bypass grafting (CABG). To define the risk factors for CS in patients who undergo CABG and create a risk-predictive model is crucial.

METHODS

In this observational study, we retrospectively evaluated consecutive patients who underwent CABG between January 2018 and October 2022 at Beijing Anzhen Hospital. A total of 496 patients were enrolled and categorized into the training (396 cases) and internal test (100 cases) sets. The variables significantly associated with mortality (p < 0.05) were analyzed using logistic regression analyses.

RESULTS

The E/A ratio at admission, postoperative brain natriuretic peptide, postoperative arterial lactate, two or more arrhythmias at the same time after CABG, and carotid artery stenosis at admission were identified as independent prognostic factors for in-hospital mortality after multivariate logistic regression analysis. The CS after CABG score (ACCS) was established and three classes of ACCS, named classes I (ACCS, <20), II (ACCS, 20-30), and III (ACCS, >30), made up the risk model. The ACCS showed better discrimination with an AUROC of 0.937 (95% confidence interval, 0.982-0.892) and calibration with the Hosmer-Lemeshow test (X2 = 5.854 with 8 df; p = 0.664). In addition, tenfold cross-validation demonstrated that the mean misdiagnosis rate was 5.56% and the lowest misdiagnosis rate was 6.38%.

CONCLUSION

The ACCS score represents a risk-predictive model for in-hospital mortality of patients with CS after CABG in acute care settings. Patients identified as class III may have a worse prognosis.

Oxygenation management during veno-arterial ECMO support for cardiogenic shock: a multicentric retrospective cohort study

BACKGOUND

Hyperoxemia is common and associated with poor outcome during veno-arterial extracorporeal membrane oxygenation (VA ECMO) support for cardiogenic shock. However, little is known about practical daily management of oxygenation. Then, we aim to describe sweep gas oxygen fraction (FSO2), postoxygenator oxygen partial pressure (PPOSTO2), inspired oxygen fraction (FIO2), and right radial arterial oxygen partial pressure (PaO2) between day 1 and day 7 of peripheral VA ECMO support. We also aim to evaluate the association between oxygenation parameters and outcome. In this retrospective multicentric study, each participating center had to report data on the last 10 eligible patients for whom the ICU stay was terminated. Patients with extracorporeal cardiopulmonary resuscitation were excluded. Primary endpoint was individual mean FSO2 during the seven first days of ECMO support (FSO2 mean (day 1-7)).

RESULTS

Between August 2019 and March 2022, 139 patients were enrolled in 14 ECMO centers in France, and one in Switzerland. Among them, the median value for FSO2 mean (day 1-7) was 70 [57; 79] % but varied according to center case volume. Compared to high volume centers, centers with less than 30 VA-ECMO runs per year were more likely to maintain FSO2 ≥ 70% (OR 5.04, CI 95% [1.39; 20.4], p = 0.017). Median value for right radial PaO2 mean (day 1-7) was 114 [92; 145] mmHg, and decreased from 125 [86; 207] mmHg at day 1, to 97 [81; 133] mmHg at day 3 (p < 0.01). Severe hyperoxemia (i.e. right radial PaO2 ≥ 300 mmHg) occurred in 16 patients (12%). PPOSTO2, a surrogate of the lower body oxygenation, was measured in only 39 patients (28%) among four centers. The median value of PPOSTO2 mean (day 1-7) value was 198 [169; 231] mmHg. By multivariate analysis, age (OR 1.07, CI95% [1.03-1.11], p < 0.001), FSO2 mean (day 1-3)(OR 1.03 [1.00-1.06], p = 0.039), and right radial PaO2 mean (day 1-3) (OR 1.03, CI95% [1.00-1.02], p = 0.023) were associated with in-ICU mortality.

CONCLUSION

In a multicentric cohort of cardiogenic shock supported by VA ECMO, the median value for FSO2 mean (day 1-7) was 70 [57; 79] %. PPOSTO2 monitoring was infrequent and revealed significant hyperoxemia. Higher FSO2 mean (day 1-3) and right radial PaO2 mean (day 1-3) were independently associated with in-ICU mortality.

Infection in ECMO patients: Changes in epidemiology, diagnosis and prevention

Patients with prolonged duration of extracorporeal membrane oxygenation support (ECMO) are a vulnerable population for sepsis, particularly ventilator-associated pneumonia and bloodstream infections. Rates differ between venous-arterial and venous-venous ECMO patients and according to the cannulation technique used. The presence of particular organisms depends on local epidemiology, antibiotic exposure, and the duration of the intervention; patients undergoing ECMO for more than three weeks present a high risk of persistent candidemia. Recognizing predisposing factors, and establishing the best preventive interventions and therapeutic choices are critical to optimizing the management of these complications. Infection control practices, including shortening the period of the indwelling devices, and reducing antibiotic exposure, must be followed meticulously. Innovations in oxygenator membranes require an updated approach. Hand hygiene and avoiding breaking the circuit-oxygenator sterility are cornerstones. ECMO management would benefit from clearer definitions, optimization of infection control strategies, and updated infectious clinical practice guidelines.

Extracorporeal Membrane Oxygenation Without Invasive Ventilation for Respiratory Failure in Adults: A Systematic Review

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) is an advanced treatment for acute severe respiratory failure. Patients on ECMO are frequently maintained sedated and immobilized until weaning from ECMO, first, and then from mechanical ventilation. Avoidance of sedation and invasive ventilation during ECMO may have potential advantages. We performed a systematic literature review to assess efficacy and safety of awake ECMO without invasive ventilation in patients with respiratory failure.

DATA SOURCES

PubMed, Web of Science, and Scopus were searched for studies reporting outcome of awake ECMO for adult patients with respiratory failure.

STUDY SELECTION

We included all studies reporting outcome of awake ECMO in patients with respiratory failure. Studies on ECMO for cardiovascular failure, cardiac arrest, or perioperative support and studies on pediatric patients were excluded. Two investigators independently screened and selected studies for inclusion.

DATA EXTRACTION

Two investigators abstracted data on study characteristics, rate of awake ECMO failure, and mortality. Primary outcome was rate of awake ECMO failure (need for intubation). Pooled estimates with corresponding 95% CIs were calculated. Subgroup analyses by setting were performed.

DATA SYNTHESIS

A total of 57 studies (28 case reports) included data from 467 awake ECMO patients. The subgroup of patients with acute respiratory distress syndrome showed a pooled estimate for awake ECMO failure of 39.3% (95% CI, 24.0-54.7%), while in patients bridged to lung transplantation, pooled estimate was 23.4% (95% CI, 13.3-33.5%). Longest follow-up mortality was 121 of 439 (pooled estimate, 28%; 95% CI, 22.3-33.6%). Mortality in patients who failed awake ECMO strategy was 43 of 74 (pooled estimate, 57.2%; 95% CI, 40.2-74.3%). Two cases of cannula self-removal were reported.

CONCLUSIONS

Awake ECMO is feasible in selected patients, although the effect on outcome remains to be demonstrated. Mortality is almost 60% in patients who failed awake ECMO strategy.

Standardized approach for extubation during extracorporeal membrane oxygenation in severe acute respiratory distress syndrome: a prospective observational study

BACKGROUND

Extubation during extracorporeal oxygenation (ECMO) in severe acute respiratory distress syndrome (ARDS) has not been well studied. Despite the potential benefits of this strategy, weaning from ECMO before liberation from invasive mechanical ventilation remains the most frequent approach. Our aim was to evaluate the safety and feasibility of a standardized approach for extubation during ECMO in patients with severe ARDS.

RESULTS

We conducted a prospective observational study to assess the safety and feasibility of a standardized approach for extubation during ECMO in severe ARDS among 254 adult patients across 4 intensive care units (ICU) from 2 tertiary ECMO centers over 6 years. This consisted of a daily assessment of clinical and gas exchange criteria based on an Extracorporeal Life Support Organization guideline, with extubation during ECMO after validation by a dedicated intensive care medicine specialist. Fifty-four (21%) patients were extubated during ECMO, 167 (66%) did not reach the clinical criteria, and in 33 (13%) patients, gas exchange precluded extubation during ECMO. At ECMO initiation, there were fewer extrapulmonary organ dysfunctions (lower SOFA score [OR, 0.88; 95% CI, 0.79-0.98; P = .02] with similar PaO2/FiO2) when compared with patients not extubated during ECMO. Extubation during ECMO associated with shorter duration of invasive mechanical ventilation (7 (4-18) vs. 32 (18-54) days; P < .01) and of ECMO (12 (7-25) vs. 19 (10-41) days; P = .01). This was accompanied by a lower incidence of hemorrhagic shock (2 vs. 11%; P = .05), but more cannula-associated deep vein thrombosis (49 vs. 31%; P = .02) and failed extubation (20 vs. 6%; P < .01). There were no increased major adverse events. Extubation during ECMO is associated with a lower risk of all-cause death, independently of measured confounding (adjusted logistic regression OR 0.23; 95% confidence interval 0.08-0.69, P = .008).

CONCLUSIONS

A standardized approach was safe and feasible allowing extubation during ECMO in 21% of patients with severe ARDS, selecting patients who will have a shorter duration of invasive mechanical ventilation, ECMO course, and ICU stay, as well as fewer infectious complications, and high hospital survival.

Early extubation in extracorporeal life support patients: A propensity score-matched study

BACKGROUND

Extubation strategy in extracorporeal life support patients remains unclear, and literature only reports studies with significant biases.

OBJECTIVES

To explore the prognostic impact of an early ventilator-weaning strategy in assisted patients after controlling for confounding factors.

METHODS

A 10-year retrospective study included 241 patients receiving extracorporeal life support for at least 48 h, corresponding to a total of 977 days spent on assistance. The a priori probability of extubation for each day of assistance was calculated according to daily biological examinations, drug doses, clinical observations, and admission data to pair each day containing an extubation with one on which the patient was not extubated. The primary outcome was survival at day 28. The secondary outcomes were survival at day 7, respiratory infections, and safety criteria.

RESULTS

Two similar cohorts of 61 patients were generated. Survival at day 28 was better in patients extubated under assistance in univariate and multivariate (HR = 0.37 [0.2-0.68], p-value = 0.002) analyses. Patients who underwent failed early extubation did not have a different prognosis from those without early extubation. Successful early extubation was associated with a better outcome than a failed or no attempt at early extubation. Survival at day 7 and the rate of respiratory infections were better in early-extubated patients. Safety data did not differ between the two groups.

CONCLUSIONS

Early extubation during assistance was associated with a superior outcome in our propensity-matched cohort study. The safety data were reassuring. However, due to the lack of prospective randomized studies, the causality remains uncertain.

Nosocomial infections during extracorporeal membrane oxygenation

PURPOSE OF THE REVIEW

The aim of this review is to present the latest evidence regarding the prevention, diagnosis and treatment of nosocomial infections during extracorporeal membrane oxygenation (ECMO) support.

RECENT FINDINGS

New descriptive data from the Extracorporeal Life Support Organisation (ELSO) registry and single centre studies have been published. In parallel, there is an increase in the availability of evidence about the diagnostic accuracy of infection markers, yield of routine cultures, effectivity of antibiotic prophylaxis and other preventive measures.

SUMMARY

ECMO is a rescue therapy for severe hemodynamic or respiratory failure. Nosocomial infections on ECMO support are frequent (infection rate ranging between 20.5% to more than 50% of ECMO runs) and have impact in survival, with reported increases in the risk of death up to 63% in infected patients. However, diagnosis and treatment are challenging, as the unique relationship between patient and circuit may act as a confounder for infection and exacerbate the variability of antibiotic pharmacokinetics in critical illness. Clinical practice regarding antibiotic treatment and infection prevention is not yet supported by high-quality evidence.

Determinants of Arterial Pressure of Oxygen and Carbon Dioxide in Patients Supported by Veno-Arterial ECMO

Background: The present study aimed to assess the determinants of arterial partial pressure of oxygen (PaO₂) and carbon dioxide (PaCO₂) in the early phase of veno-arterial extracorporeal membrane oxygenation (VA ECMO) support. Even though the guidelines considered both the risks of hypoxemia and hyperoxemia during ECMO support, there are a lack of data concerning the patients supported by VA ECMO. Methods: This is a retrospective, monocentric, observational cohort study in a university-affiliated cardiac intensive care unit. Hemodynamic parameters, ECMO parameters, ventilator settings, and blood gas analyses were collected at several time points during the first 48 h of VA ECMO support. For each timepoint, the blood samples were drawn simultaneously from the right radial artery catheter, VA ECMO venous line (before the oxygenator), and from VA ECMO arterial line (after the oxygenator). Univariate followed by multivariate mixed-model analyses were performed for longitudinal data analyses. Results: Forty-five patients with femoro-femoral peripheral VA ECMO were included. In multivariate analysis, the patients' PaO₂ was independently associated with Q_EC, F_DO₂, and time of measurement. The patients' PaCO₂ was associated with the sweep rate flow and the P_preCO₂. Conclusions: During acute VA ECMO support, the main determinants of patient oxygenation are determined by VA ECMO parameters.

Optimizing PO2 during peripheral veno-arterial ECMO: a narrative review

During refractory cardiogenic shock and cardiac arrest, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is used to restore a circulatory output. However, it also impacts significantly arterial oxygenation. Recent guidelines of the Extracorporeal Life Support Organization (ELSO) recommend targeting postoxygenator partial pressure of oxygen (P_POSTO₂) around 150 mmHg. In this narrative review, we intend to summarize the rationale and evidence for this P_POSTO₂ target recommendation. Because this is the most used configuration, we focus on peripheral VA-ECMO. To date, clinicians do not know how to set the sweep gas oxygen fraction (F_SO₂). Because of the oxygenator's performance, arterial hyperoxemia is common during VA-ECMO support. Interpretation of oxygenation is complex in this setting because of the dual circulation phenomenon, depending on both the native cardiac output and the VA-ECMO blood flow. Such dual circulation results in dual oxygenation, with heterogeneous oxygen partial pressure (PO₂) along the aorta, and heterogeneous oxygenation between organs, depending on the mixing zone location. Data regarding oxygenation during VA-ECMO are scarce, but several observational studies have reported an association between hyperoxemia and mortality, especially after refractory cardiac arrest. While hyperoxemia should be avoided, there are also more and more studies in non-ECMO patients suggesting the harm of a too restrictive oxygenation strategy. Finally, setting F_SO₂ to target strict normoxemia is challenging because continuous monitoring of postoxygenator oxygen saturation is not widely available. The threshold of P_POSTO₂ around 150 mmHg is supported by limited evidence but aims at respecting a safe margin, avoiding both hypoxemia and severe hyperoxemia.

Awake extracorporeal life support and physiotherapy in adult patients: A systematic review of the literature

OBJECTIVE

The Awake Extracorporeal Life Support (ECLS) practice combined with physiotherapy is increasing. However, available evidence for this approach is limited, with unclear indications on timing, management, and protocols. This review summarizes available literature regarding Awake ECLS and physiotherapy application rates, practices, and outcomes in adults, providing indications for future investigations.

METHODS

Four databases were screened from inception to February 2021, for studies reporting adult Awake ECLS with/without physiotherapy. Primary outcome was hospital discharge survival, followed by Extracorporeal Membrane Oxygenation (ECMO) duration, extubation, Intensive Care Unit stay.

RESULTS

Twenty-nine observational studies and one randomized study were selected, including 1,157 patients (males n = 611/691, 88.4%) undergoing Awake ECLS. Support type was reported in 1,089 patients: Veno-Arterial ECMO (V-A = 39.6%), Veno-Venous ECMO (V-V = 56.8%), other ECLS (3.6%). Exclusive upper body cannulation and femoral cannulation were applied in 31% versus 69% reported cases (n = 931). Extubation was successful in 63.5% (n = 522/822) patients during ECLS. Physiotherapy details were given for 676 patients: exercises confined in bed for 47.9% (n = 324) patients, mobilization until standing in 9.3% (n = 63) cases, ambulation performed in 42.7% (n = 289) patients. Femoral cannulation, extubation and V-A ECMO were mostly correlated to complications. Hospital discharge survival observed in 70.8% (n = 789/1114).

CONCLUSION

Awake ECLS strategy associated with physiotherapy is performed regardless of cannulation approach. Ambulation, as main objective, is achieved in almost half the population examined. Prospective studies are needed to evaluate safety and efficacy of physiotherapy during Awake ECLS, and suitable patient selection. Guidelines are required to identify appropriate assessment/evaluation tools for Awake ECLS patients monitoring.

Mechanical Ventilation during ECMO: Lessons from Clinical Trials and Future Prospects

Acute Respiratory Distress Syndrome (ARDS) accounts for 10% of ICU admissions and affects 3 million patients each year. Despite decades of research, it is still associated with one of the highest mortality rates in the critically ill. Advances in supportive care, innovations in technologies and insights from recent clinical trials have contributed to improved outcomes and a renewed interest in the scope and use of Extracorporeal life support (ECLS) as a treatment for severe ARDS, including high flow veno-venous Extracorporeal Membrane Oxygenation (VV-ECMO) and low flow Extracorporeal Carbon Dioxide Removal (ECCO2R). The rationale being that extracorporeal gas exchange allows the use of lung protective ventilator settings, thereby minimizing ventilator-induced lung injury (VILI). Ventilation strategies are adapted to the patient's condition during the different stages of ECMO support. Several areas in the management of mechanical ventilation in patients on ECMO, such as the best ventilator mode, extubation-decannulation sequence and tracheostomy timing, are tailored to the patients' recovery. Reduction in sedation allowing mobilization, nutrition and early rehabilitation are subsequent therapeutic goals after lung rest has been achieved.

Technique for circuit exchange in high-risk patients on extracorporeal life support

Exchanging circuits in patients undergoing extracorporeal life support (ECLS) for component failure can be a life-threatening endeavor if the patient has no native organ function and is fully dependent on ECLS. Traditional circuit exchanges involve replacing the entire circuit at once, leading to a sufficient loss of support that risks hemodynamic deterioration in the absence of mechanical ventilation or mechanical circulatory support. A staged approach is described using a parallel circuit configuration to reduce the risk of physiologic decompensation in patients with total dependence on ECLS. The approach involves splicing in a second primed circuit in parallel, transitioning flow incrementally from old to new circuit, and removing the old circuit. This approach provides hemodynamic and physiologic stability even in patients with absent underlying cardiopulmonary function.

Clinical Benefit of Extubation in Patients on Venoarterial Extracorporeal Membrane Oxygenation

OBJECTIVES

Although patients on venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock are usually supported with mechanical ventilation, it is not clear whether sedation cessation and extubation might improve outcomes.

DESIGN

Retrospective cohort study with propensity score overlap weighting analysis.

SETTING

Three ICUs in a 1,500-bed tertiary university hospital.

PATIENTS

From an overall cohort of 641 patients with venoarterial-extracorporeal membrane oxygenation support, the primary analysis was performed in 344 patients who had been successfully decannulated in order to reduce immortal time bias.

MEASUREMENTS AND MAIN RESULTS

Seventy-five patients (22%) were extubated during extracorporeal membrane oxygenation support and were subsequently decannulated alive. Forty-nine percent received noninvasive ventilation, and 25% had emergency reintubation for respiratory, neurologic, or hemodynamic reasons. Higher Simplified Acute Physiology Score II at admission (odds ratio, 0.97; 95% CI [0.95-0.99]; p = 0.008) was associated with a lower probability of extubation, whereas cannulation in cardiac surgery ICU (odds ratio, 3.14; 95% CI [1.21-8.14]; p = 0.018) was associated with an increased probability. Baseline characteristics were well balanced after propensity score overlap weighting. The number of ICU-free days within 30 days of extracorporeal membrane oxygenation decannulation was significantly higher among extubated patients compared with nonextubated patients (22 d [11-26 d] vs 18 d [7-25 d], respectively; p = 0.036). There were no differences in other outcomes including ventilator-associated pneumonia (odds ratio, 0.96; 95% CI [0.51-1.82]; p = 0.90) and all-cause mortality within 30 days of extracorporeal membrane oxygenation decannulation (5% vs 17%; hazard ratio, 0.54; 95% CI [0.19-1.59]; p = 0.27).As a secondary analysis, outcomes were compared in the overall cohort of 641 venoarterial extracorporeal membrane oxygenation-supported patients. Results were consistent with the primary analysis as extubated patients had a higher number of ICU-free days (18 d [0-24 d] vs 0 d [0-18 d], respectively; < 0.001) and a lower risk of death within 30 days of extracorporeal membrane oxygenation cannulation (hazard ratio, 0.45; 95% CI [0.29-0.71]; p = 0.001).

CONCLUSIONS

Extubation during venoarterial-extracorporeal membrane oxygenation support is safe, feasible, and associated with greater ICU-free days.

Ultrasound Assessment in Cardiogenic Shock Weaning: A Review of the State of the Art

Cardiogenic shock (CS) is associated with a high in-hospital mortality despite the achieved advances in diagnosis and management. Invasive mechanical ventilation and circulatory support constitute the highest step in cardiogenic shock therapy. Once established, taking the decision of weaning from such support is challenging. Intensive care unit (ICU) bedside echocardiography provides noninvasive, immediate, and low-cost monitoring of hemodynamic parameters such as cardiac output, filling pressure, structural disease, congestion status, and device functioning. Supplemented by an ultrasound of the lung and diaphragm, it is able to provide valuable information about signs suggesting a weaning failure. The aim of this article was to review the state of the art taking into account current evidence and knowledge on ICU bedside ultrasound for the evaluation of weaning from mechanical ventilation and circulatory support in cardiogenic shock.

Evaluation of the Oxiris Membrane in Cardiogenic Shock Requiring Extracorporeal Membrane Oxygenation Support: Study Protocol for a Single Center, Single-Blind, Randomized Controlled Trial

Background: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is the rescue treatment proposed to patients with refractory cardiogenic shock. The VA-ECMO implantation promotes inflammation and ischemia-reperfusion injuries through the VA-ECMO flow, causing digestive mucosa barrier disrupture and inducing translocation of bacterial wall components-Lipopolysaccharides (LPS) with further inflammation and circulatory impairment. LPS is a well-studied surrogate indicator of bacterial translocation. Oxiris membrane is a promising and well-tolerated device that can specifically remove LPS. The main study aim is to compare the LPS elimination capacity of Oxiris membrane vs. a non-absorbant classical renal replacement (RRT) membrane in patients with cardiogenic shock requiring VA-ECMO. Methods: ECMORIX is a randomized, prospective, single-center, single-blind, parallel-group, controlled study. It compares the treatment with Oxiris membrane vs. the standard continuous renal replacement therapy care in patients with cardiogenic shock support by peripheral VA-ECMO. Forty patients will be enrolled in both treatment groups. The primary endpoint is the value of LPS serum levels after 24 h of treatment. LPS serum levels will be monitored during the first 72 h of treatment, as clinical and cardiac ultrasound parameters, biological markers of inflammation and 30-day mortality. Discussion: Oxiris membrane appears to be beneficial in controlling the VA-ECMO-induced ischemia-reperfusion inflammation by LPS removal. ECMORIX results will be of major importance in the management of severe cases requiring VA-ECMO and will bring pathophysiological insights about the LPS role in this context. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT04886180.

Management of Adult Patients Supported with Venovenous Extracorporeal Membrane Oxygenation (VV ECMO): Guideline from the Extracorporeal Life Support Organization (ELSO)

Disclaimer: The use of venovenous extracorporeal membrane oxygenation (VV ECMO) in adults has rapidly increased worldwide. This ELSO guideline is intended to be a practical guide to patient selection, initiation, cannulation, management, and weaning of VV ECMO for adult respiratory failure. This is a consensus document which has been updated from the previous version to provide guidance to the clinician.

Extracorporeal Carbon Dioxide Removal in the Treatment of Status Asthmaticus

OBJECTIVES

Venovenous extracorporeal carbon dioxide removal may be lifesaving in the setting of status asthmaticus.

DESIGN

Retrospective review.

SETTING

Medical ICU.

PATIENTS

Twenty-six adult patients with status asthmaticus treated with venovenous extracorporeal carbon dioxide removal.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic data and characteristics of current and prior asthma treatments were obtained from the electronic medical record. Mechanical ventilator settings, arterial blood gases, vital signs, and use of vasopressors were collected from the closest time prior to cannulation and 24 hours after initiation of extracorporeal carbon dioxide removal. Extracorporeal carbon dioxide removal settings, including blood flow and sweep gas flow, were collected at 24 hours after initiation of extracorporeal carbon dioxide removal. Outcome measures included rates of survival to hospital discharge, ICU and hospital lengths of stay, duration of invasive mechanical ventilation and extracorporeal carbon dioxide removal support, and complications during extracorporeal carbon dioxide removal. Following the initiation of extracorporeal carbon dioxide removal, blood gas values were significantly improved at 24 hours, as were peak airway pressures, intrinsic positive end-expiratory pressure, and use of vasopressors. Survival to hospital discharge was 100%. Twenty patients (76.9%) were successfully extubated while receiving extracorporeal carbon dioxide removal support; none required reintubation. The most common complication was cannula-associated deep venous thrombosis (six patients, 23.1%). Four patients (15.4%) experienced bleeding that required a transfusion of packed RBCs.

CONCLUSIONS

In the largest series to date, use of venovenous extracorporeal carbon dioxide removal in patients with status asthmaticus can provide a lifesaving means of support until the resolution of the exacerbation, with an acceptably low rate of complications. Early extubation in select patients receiving extracorporeal carbon dioxide removal is safe and feasible and avoids the deleterious effects of positive-pressure mechanical ventilation in this patient population.

Risk factors and prognosis of nosocomial pneumonia in patients undergoing extracorporeal membrane oxygenation: a retrospective study

Objective

We aimed to examine the risk factors and prognosis of nosocomial pneumonia (NP) during extracorporeal membrane oxygenation (ECMO).

Methods

We retrospectively analyzed data of patients who received ECMO at the Affiliated Hangzhou Hospital of Nanjing Medical University between January 2013 and August 2019. The primary outcome was the survival-to-discharge rate.

Results

Sixty-nine patients who received ECMO were enrolled, median age 42 years and 26 (37.7%) women; 14 (20.3%) patients developed NP. The NP incidence was 24.7/1000 ECMO days. Patients with NP had a higher proportion receiving veno-venous (VV) ECMO (50% vs. 7.3%); longer ECMO support duration (276 vs. 140 hours), longer ventilator support duration before ECMO weaning (14.5 vs. 6 days), lower ECMO weaning success rate (50.0% vs. 81.8%), and lower survival-to-discharge rate (28.6% vs. 72.7%) than patients without NP. Multivariable analysis showed independent risk factors that predicted NP during ECMO were ventilator support duration before ECMO weaning (odds ratio [OR] = 1.288; 95% confidence interval [CI]: 1.111–1.494) and VV ECMO mode (OR = 10.970; 95% CI: 1.758–68.467).

Conclusion

NP during ECMO was associated with ventilator support duration before ECMO weaning and VV ECMO mode. Clinicians should shorten the respiratory support duration for patients undergoing ECMO to prevent NP.

Awake venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock

BACKGROUND 

Venoarterial-extracorporeal membrane oxygenation (VA-ECMO) is currently one of the first-line therapies for refractory cardiogenic shock (CS), but its applicability is undermined by the high morbidity associated with its complications, especially those related to mechanical ventilation (MV). We aimed to assess the prognostic impact of keeping patients in refractory CS awake at cannulation and during the VA-ECMO run.

METHODS 

A 7-year database of patients given peripheral VA-ECMO support was used to conduct a propensity-score (PS)-matched analysis to balance their clinical profiles. Patients were classified as 'awake ECMO' or 'non-awake ECMO', respectively, if invasive MV was used during ≤50% or >50% of the VA-ECMO run. Primary outcomes included ventilator-associated pneumonia and ECMO-related complication rates, and secondary outcomes were 60-day and 1-year mortality. A multivariate logistic-regression analysis was used to identify whether MV at cannulation was independently associated with 60-day mortality.

RESULTS 

Among 231 patients included, 91 (39%) were 'awake' and 140 (61%) 'non-awake'. After PS-matching adjustment, the 'awake ECMO' group had significantly lower rates of pneumonia (35% vs. 59%, P = 0.017), tracheostomy, renal replacement therapy, and less antibiotic and sedative consumption. This strategy was also associated with reduced 60-day (20% vs. 41%, P = 0.018) and 1-year mortality rates (31% vs. 54%, P = 0.021) compared to the 'non-awake' group, respectively. Lastly, MV at ECMO cannulation was independently associated with 60-day mortality.

CONCLUSION 

An 'awake ECMO' management in VA-ECMO-supported CS patients is feasible, safe, and associated with improved short- and long-term outcomes.

Extubation during extracorporeal membrane oxygenation in adults: An international qualitative study on experts' opinions

BACKGROUND

Extracorporeal membrane oxygenation in adults (adult-ECMO), a modification of cardiopulmonary bypass is increasingly used. Liberation from mechanical ventilation, or extubation, during adult-ECMO remains a challenge.

OBJECTIVES

This study aimed to understand expert perceptions of the reasonableness of extubation during adult-ECMO and the usefulness of an extubation clinical practice guideline (ECPG).

METHODS

Homogeneous purposive sampling, focus groups, and interviews with a discussion guide, and direct content, thematic analysis were used.

RESULTS

Fourteen volunteers participated with different educational levels (79% Doctor of Medicine, 14% Registered Nurse, 7% Nurse Practitioner), from high-volume ECMO centers of various annual ECMO runs (50% 30-49 ECMO/year, 36% 50-99 ECMO/year, 14% >100 ECMO/year) worldwide (64% North America, 21% South America, 7% Europe, 7% Asia). Seven themes were identified: paucity of evidence, mindsets towards using an ECPG, barriers, criteria and benefits of extubation, culture towards extubation and vision of the future. Participants recommended aiming for extubation based on patient selection, and a standardized extubation approach with an ECPG or team decision-making.

CONCLUSION

Application of adult-ECMO is expanding, during which extubation remains difficult. Experts recommend two methods of a standardized extubation approach.

Characteristics of Patients Managed without Positive Pressure Ventilation While on Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome

Background: Extracorporeal membrane oxygenation (ECMO) has expanding indications for cardiopulmonary resuscitation including severe acute respiratory distress syndrome (ARDS). Despite the adjunct of ECMO for patients with severe ARDS, they often have prolonged mechanical ventilation and are subject to many of its inherent complications. Here, we describe patients who were cannulated for venovenous (VV) ECMO and were taken off positive pressure ventilation. Methods: This is a primary analysis of patients admitted at a tertiary medical center between the dates of August 2014 to January 2020 who were cannulated to ECMO for refractory respiratory failure. We included all patients ≥18 years old. Patients who were extubated or had a tracheostomy and taken off positive pressure while on ECMO were classified as “off positive pressure ventilation (PPV)” and were compared to patients who remained “on PPV” while on ECMO. Primary outcome was survival to hospital discharge. Secondary outcomes were ventilator free days at 30 days and 60 days after ECMO cannulation, time from cannulation to date of first out-of-bed (OOB), and hospital length of stay (LOS). Patient characteristics were derived from routine clinical information in the electronic health record (EHR). Categorical characteristics were compared using chi-square test or Fisher exact test. Continuous characteristics were compared using independent samples t-test or Wilcoxon–Mann–Whitney test. p-values were reported from all analysis. Results: Sixty-five patients were included in this retrospective analysis. Forty-eight were managed on ECMO with PPV and 17 patients were removed from PPV. Patients removed from PPV had significantly higher lung injury scores prior to cannulation (2.5 ± 0.6 vs. 1.04 ± 0.3; p = 0.031) and non-significantly longer duration of ventilation prior to ECMO (6.1 days ± 2.1 vs. 5.0 days ± 01.1; p = 0.634). One hundred percent (100%) of patients removed from PPV survived to hospital discharge compared to 45% who received PPV throughout their duration of ECMO management (p < 0.001). The mean ventilator free days at day 60 was 15 with PPV and 36 without PPV (p = 0.003). The average duration from cannulation to mobilization (i.e., out-of-bed) was 18 days with PPV and 7 days without PPV (p = 0.015). Conclusions: Patients taken off PPV while on ECMO had a very high likelihood of survival to discharge and were mobilized in half as many days. While this likely reflects patient selection, the benefit of early mobilization is well documented and the approach of extubating while on ECMO warrants further investigation.

Extracorporeal and advanced therapies for progressive refractory near-fatal acute severe asthma in children

Asthma is the most common chronic illness and is one of the most common medical emergencies in children. Progressive refractory near-fatal asthma requiring intubation and mechanical ventilation can lead to death. Extracorporeal membrane oxygenation (ECMO) can provide adequate gas exchange during acute respiratory failure although data on outcomes in children requiring ECMO support for status asthmaticus is sparse with one study reporting survival rates of nearly 85% with asthma being one of the best outcome subsets for patients with refractory respiratory failure requiring ECMO support. We describe the current literature on the use of ECMO and other advanced extracorporeal therapies available for children with acute severe asthma. We also review other advanced invasive and noninvasive therapies in acute severe asthma both before and while on ECMO support.

Pulmonary complications associated with veno-arterial extra-corporeal membrane oxygenation: a comprehensive review

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a life-saving technology that provides transient respiratory and circulatory support for patients with profound cardiogenic shock or refractory cardiac arrest. Among its potential complications, VA-ECMO may adversely affect lung function through various pathophysiological mechanisms. The interaction of blood components with the biomaterials of the extracorporeal membrane elicits a systemic inflammatory response which may increase pulmonary vascular permeability and promote the sequestration of polymorphonuclear neutrophils within the lung parenchyma. Also, VA-ECMO increases the afterload of the left ventricle (LV) through reverse flow within the thoracic aorta, resulting in increased LV filling pressure and pulmonary congestion. Furthermore, VA-ECMO may result in long-standing pulmonary hypoxia, due to partial shunting of the pulmonary circulation and to reduced pulsatile blood flow within the bronchial circulation. Ultimately, these different abnormalities may result in a state of persisting lung inflammation and fibrotic changes with concomitant functional impairment, which may compromise weaning from VA-ECMO and could possibly result in long-term lung dysfunction. This review presents the mechanisms of lung damage and dysfunction under VA-ECMO and discusses potential strategies to prevent and treat such alterations.

Extubation and Noninvasive Ventilation of Patients Supported by Extracorporeal Life Support for Cardiogenic Shock: A Single-Center Retrospective Observational Cohort Study

Background:

Temporary extracorporeal life support (ECLS) by venoarterial extracorporeal membrane oxygenation is an emerging therapy for patients with severe, ongoing cardiogenic shock. After stabilization of the hemodynamic status and end-organ function, sedation weaning, extubation, and noninvasive ventilation (NIV) can be attempted. The goal of this study was to analyze the feasibility of extubation and NIV during versus after ECLS for cardiogenic shock.

Methods:

Single-center retrospective observational study of 132 patients undergoing ECLS due to severe cardiogenic shock between January 2015 and December 2016 at a tertiary care university hospital.

Results:

Patients received ECLS due to acute myocardial infarction (20.6%), ongoing cardiogenic shock (15.2%), postoperative low-cardiac-output syndrome (24.2%), and extracorporeal cardiopulmonary resuscitation (40.2%). Overall, intensive care unit survival was 44.7%. Sixty-nine (52.3%) patients could never be extubated. Forty-three (32.6%) were extubated while on ECLS support (group 1) and 20 (15.1%) were extubated after weaning from ECLS (group 2). Patients extubated during ECLS had a significantly shorter total time on ventilator (P = .003, mean difference: −284 hours [95% confidence limits: −83 to −484]) and more invasive ventilation free days (P = .0018; mean difference 8 days [95%CL: 2-14]). Mortality and NIV failure rates were similar between groups.

Conclusions:

Extubation and NIV are feasible in patients who stabilize during ECLS therapy. Further studies need to address whether extubation has the potential to improve patients outcome or if the feasibility to extubate is a surrogate for disease severeness.

Risk Factors of Bleeding in Patients Undergoing Venoarterial Extracorporeal Membrane Oxygenation

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (VA ECMO) is increasingly being used for circulatory shock. Bleeding is a frequent complication and is associated with increased mortality. The purpose of our study was to identify factors associated with early major bleeding after VA ECMO initiation.

METHODS

We performed a retrospective observational study based on our database. In accordance with the Extracorporeal Life Support Organization definition, the population was divided in two groups: major bleeding events (group B) and no major bleeding events (group O). We collected data on all major bleeding events occurring during the first 48 hours after VA ECMO initiation.

RESULTS

Of the 243 patients analyzed, 111 patients (46%) had an early major bleeding event. Independent risk factors associated with early major bleeding events were postcardiotomy VA ECMO (odds ratio [OR] 1.98; 95% confidence interval [CI], 1.08 to 3.62; P = .02), body mass index (OR 0.91; 95% CI, 0.85 to 0.98; P = .01), hemoglobinemia (OR 0.8; 95% CI, 0.7 to 0.92; P = .002), fibrinogen (OR 0.67; 95% CI, 0.52 to 0.84; P = .001), and pH (OR 0.15; 95% CI, 0.02 to 1.04; P = .05). By using a receiver-operating characteristics curve analysis, hemoglobin level less than 9 g dL^-1, fibrinogen level less than 2 g L^-1, pH lower than 7.12, and body mass index below 25 kg/m² were identified to predict early major bleeding events. Major bleeding events were independently associated with mortality (OR 2.54; CI 95%, 1.38 to 4.66; P = .01).

CONCLUSIONS

We found that postcardiotomy VA ECMO, hemoglobin levels less than 9 g dL^-1, fibrinogen levels less than 2 g L^-1, pH lower than 7.12, and body mass index below 25 kg/m² were associated with a higher risk for early major bleeding events.

A winter to remember! Extracorporeal membrane oxygenation for life-threatening asthma in children: A case series and review of literature

Progressive refractory near-fatal asthma requiring intubation and mechanical ventilation can lead to death. Data on outcomes in children requiring extracorporeal membrane oxygenation (ECMO) support for status asthmaticus is sparse. We describe our experience of three patients in the winter of 2018 to 2019 successfully rescued with ECMO. We also report our novel use of extubation while still being on ECMO support. Awareness and use of ECMO in refractory asthma can help lower the mortality for this very common disease in children. We also review the current literature on the use of ECMO and other extracorporeal therapies in asthma.

Mechanical thrombectomy in acute ischemic stroke patients under venoarterial extracorporeal membrane oxygenation

BACKGROUND

Use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in adult patients to treat refractory cardiogenic shock has increased in recent years, and ischemic stroke is the most frequent VA-ECMO-induced cerebrovascular complication. No adult case of mechanical thrombectomy (MT) has been reported.

METHODS

Retrospective observational study of hospital medical records of patients who received circulatory support with VA-ECMO with acute ischemic stroke treated with MT, from 2006 to 2018.

RESULTS

Two adult patients on VA-ECMO with acute ischemic stroke treated with MT were found. Both cases were successfully treated.

CONCLUSION

These cases illustrate the feasibility of performing MT in adult patients on ECMO.