ECLS-associated infections in adults: what we know and what we don't yet know

The utility of sepsis scores for predicting blood stream infections in extracorporeal membrane oxygenation

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is an increasingly used modality of life support with high risk for nosocomial infections. The accuracy of sepsis prediction tools in identifying blood stream infections (BSI) in this population is unknown as measurement of multiple variables commonly associated with infection are altered by the circuit.

METHODS

This study compares all blood stream infections for patients receiving ECMO between January 2012 and December 2020 to timepoints when blood cultures were negative using the Sequential Organ Failure Assessment (SOFA), Logistic Organ Dysfunction Score (LODS), American Burn Association Sepsis Criteria (ABA), Systemic Inflammatory Response Syndrome (SIRS) scores.

RESULTS

Of the 220 patients who received ECMO during the study period, 40 (18%) had 51 blood stream infections and were included in this study. Gram-positive infections composed 57% (n = 29) of infections with E. faecalis (n = 12, 24%) being the most common organism isolated. There were no significant differences in sepsis prediction scores at the time of infection compared to infection-free time points for SOFA (median (IQR) 7 (5-9) vs. 6 (5-8), p = 0.22), LODS (median (IQR) 12 (10-14) vs. 12 (10-13), p = 0.28), ABA (median (IQR) 2 (1-3) vs. 2 (1-3) p = 0.75), or SIRS (median (IQR) 3 (2-3) vs. 3 (2-3), p = 0.20).

CONCLUSIONS

Our data shows that previously published sepsis scores are elevated throughout a patient's ECMO course, and do not correlate with bacteremia. Better predictive tools are needed to determine the appropriate timing for blood cultures in this population.

The International Society for Heart and Lung Transplantation (ISHLT): 2024 infection definitions for durable and acute mechanical circulatory support devices

Infections remain a significant concern in patients receiving mechanical circulatory support (MCS), encompassing both durable and acute devices. This consensus manuscript provides updated definitions for infections associated with durable MCS devices and new definitions for infections in acute MCS, integrating a comprehensive review of existing literature and collaborative discussions among multidisciplinary specialists. By establishing consensus definitions, we seek to enhance clinical care, facilitate consistent reporting in research studies, and ultimately improve outcomes for patients receiving MCS.

Frequency, Characteristics and Outcome of Adult Patients with Multiple Consecutive Healthcare-Associated Infections Undergoing Extracorporeal Membrane Oxygenation: A Retrospective Analysis

BACKGROUND

Data on multiple consecutive healthcare-associated infections (HAIs) in patients undergoing extracorporeal membrane oxygenation (ECMO) are limited. We aim to identify the characteristics and outcomes of multiple, consecutive HAIs.

METHODS

This retrospective cohort study included adult patients who underwent ECMO in a single cardiac intensive care unit in China from May 2015 to December 2022. The incidence, clinical characteristics, risk factors, and impact on in-hospital mortality were analyzed among patients with non-HAI, single HAI, and multiple HAIs. The pathogens and sites of each new episode of infection were evaluated and compared.

RESULTS

Of 192 patients, 92 (47.92%) developed 141 separate infections, with 41 (21.35%) experiencing multiple infections during a single ECMO period. Respiratory tract infections (RTIs) constituted the majority (75.89%), and Gram-negative bacteria were the predominant pathogens (71.63%). The proportion of RTIs decreased from 86.9% in the first infection episode to 14.3% in the third (p < 0.001), while bloodstream infections increased from 10.9% to 57.1% (p < 0.001). Furthermore, from the first to the third HAI, the proportion of Gram-positive bacteria increased from 9.8% to 42.9% (p = 0.032). Prolonged ECMO duration was the only independent risk factor for multiple consecutive HAI (OR = 1.220; p < 0.001).

CONCLUSIONS

The frequency of consecutive multiple HAIs during ECMO support was high, with distinct microbiological changes between initial and subsequent HAIs.

Diagnosis and Management of Vasoplegia in Temporary Mechanical Circulatory Support: A Narrative Review

Refractory vasodilatory shock, or vasoplegia, is a pathophysiologic state observed in the intensive care unit and operating room in patients with a variety of primary diagnoses. Definitions of vasoplegia vary by source but are qualitatively defined clinically as a normal or high cardiac index and low systemic vascular resistance causing hypotension despite high-dose vasopressors in the setting of euvolemia. This definition can be difficult to apply to patients undergoing mechanical circulatory support (MCS). A large body of mostly retrospective literature exists on vasoplegia in the non-MCS population, but the increased use of temporary MCS justifies an examination of vasoplegia in this population. MCS, particularly extracorporeal membrane oxygenation, adds complexity to the diagnosis and management of vasoplegia due to challenges in determining cardiac output (or total blood flow), lack of clarity on appropriate dosing of noncatecholamine interventions, increased thrombosis risk, the difficulty in determining the endpoints of adequate volume resuscitation, and the unclear effects of rescue agents (methylene blue, hydroxocobalamin, and angiotensin II) on MCS device monitoring and function. Care teams must combine data from invasive and noninvasive sources to diagnose vasoplegia in this population. In this narrative review, the available literature is surveyed to provide guidance on the diagnosis and management of vasoplegia in the temporary MCS population, with a focus on noncatecholamine treatments and special considerations for patients supported by extracorporeal membrane oxygenation, transvalvular heart pumps, and other ventricular assist devices.

Practices surrounding antimicrobial use in patients managed with extracorporeal membrane oxygenation: An international survey

PURPOSE

This study aimed to survey critical care clinicians and characterize their perception of antimicrobial dosing strategies in patients receiving extracorporeal membrane oxygenation (ECMO).

METHODS

International, cross-sectional survey distributed to members of the Society of Critical Care Medicine in October 2022.

RESULTS

Respondents were primarily physicians (45%), with 92% practicing in North America. Ninety-seven percent of respondents reported antimicrobial dosing in critically ill patients to be challenging, due to physiological derangements seen in the patient population. Eighty-seven percent reported consideration of physicochemical drug properties when dosing antimicrobials in ECMO-supported patients, with lipophilicity (83%) and degree of protein binding (74%) being the two most common. Respondents' approach to antimicrobial dosing strategies did not significantly differ in critically ill ECMO-supported patients, compared to patients with equal severity of illness not receiving ECMO support.

CONCLUSION

Approaches to antimicrobial dosing strategies do not significantly differ among respondents between critically ill patients on ECMO support, compared to patients with equal severity of illness not receiving ECMO support. These findings were unexpected considering the added physiologic complexity of the ECMO circuit to critically ill adult patients and the need for well designed and adequately powered studies to inform empiric dosing guidance for ECMO-supported patients.

Biofilm Assessment and Metagenomic Analysis of Venoarterial Extracorporeal Membrane Oxygenation Cannulas and Membrane Oxygenators

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) exposes the patient to infectious complications related to the cannulas or the site of insertion. The aim of the current study was to investigate and compare the prevalence of cannula and membrane oxygenators colonization using three different methods: microbiological culture, scanning electron microscopy, and metagenomic (rRNA 16S analysis). A monocentric prospective study was conducted between December 2017 and June 2018. Consecutive patients undergoing VA-ECMO support for refractory cardiac arrest or cardiogenic shock were included. Ten patients were included with a median age of 64 (52-62) years. Venoarterial extracorporeal membrane oxygenation was inserted for refractory cardiac arrest in five (50%), cardiogenic shock in four (40%), and self-poisoning in one (10%) cases. Microbiological culture of all (8/8, 100%) membrane oxygenators was negative, whereas all (10/10, 100%) were colonized by biofilm, and eight (8/9, 89%) presented bacterial DNA. Three (3/9, 33%) arterial and venous cannulas were positive in culture and seven (7/9, 78%) were colonized by biofilm, respectively. Seven (7/9, 78%) arterial and four (4/9, 44%) venous cannulas presented bacterial DNA. Colonization of cannulas and membranes is more frequent when assessed by electron microscopy or metagenomic analysis than with culture. Membrane oxygenators are more often colonized than cannulas.

Healthcare-associated infections in patients with severe COVID-19 supported with extracorporeal membrane oxygenation: a nationwide cohort study

BACKGROUND

Both critically ill patients with coronavirus disease 2019 (COVID-19) and patients receiving extracorporeal membrane oxygenation (ECMO) support exhibit a high incidence of healthcare-associated infections (HAI). However, data on incidence, microbiology, resistance patterns, and the impact of HAI on outcomes in patients receiving ECMO for severe COVID-19 remain limited. We aimed to report HAI incidence and microbiology in patients receiving ECMO for severe COVID-19 and to evaluate the impact of ECMO-associated infections (ECMO-AI) on in-hospital mortality.

METHODS

For this study, we analyzed data from 701 patients included in the ECMOSARS registry which included COVID-19 patients supported by ECMO in France.

RESULTS

Among 602 analyzed patients for whom HAI and hospital mortality data were available, 214 (36%) had ECMO-AI, resulting in an incidence rate of 27 ECMO-AI per 1000 ECMO days at risk. Of these, 154 patients had bloodstream infection (BSI) and 117 patients had ventilator-associated pneumonia (VAP). The responsible microorganisms were Enterobacteriaceae (34% for BSI and 48% for VAP), Enterococcus species (25% and 6%, respectively) and non-fermenting Gram-negative bacilli (13% and 20%, respectively). Fungal infections were also observed (10% for BSI and 3% for VAP), as were multidrug-resistant organisms (21% and 15%, respectively). Using a Cox multistate model, ECMO-AI were not found associated with hospital death (HR = 1.00 95% CI [0.79-1.26], p = 0.986).

CONCLUSIONS

In a nationwide cohort of COVID-19 patients receiving ECMO support, we observed a high incidence of ECMO-AI. ECMO-AI were not found associated with hospital death. Trial registration number NCT04397588 (May 21, 2020).

The impact of extracorporeal membrane oxygenation on antifungal pharmacokinetics: A systematic review

BACKGROUND AND OBJECTIVE

The use of extracorporeal membrane oxygenation (ECMO) as a cardiocirculatory or respiratory support has tremendously increased in critically ill patients. In the setting of ECMO support, invasive fungal infections are a severe cause of morbidity and mortality. This vulnerable population is at risk of suboptimal antifungal exposure due to an increased volume of distribution (Vd), drug sequestration and decreased clearance. Here, we aimed to summarize ex-vivo and clinical studies on the potential impact of ECMO on the pharmacokinetics (PK) of antifungal agents and dosing requirements.

METHODS

A systematic search of the literature within electronic databases PubMed and EMBASE was conducted from database inception to 30 April 2023. Inclusion criteria were as follows: critically ill patients receiving ECMO regardless of age and reporting at least one PK parameter.

RESULTS

Thirty-six studies met inclusion criteria, including seven ex-vivo experiments and 29 clinical studies evaluating three classes of antifungals: polyenes, triazoles and echinocandins. Based on the available ex-vivo PK data, we found a significant sequestration of highly lipophilic and protein-bound antifungals within the ECMO circuit such as voriconazole, posaconazole and micafungin but the PK of several antifungals remains to be addressed such as amphotericin B, isavuconazole and anidulafungin. Most clinical studies have shown increased Vd of some antifungals like fluconazole and micafungin, particularly in the pediatric population. Conflicting data exist about caspofungin exposure.

CONCLUSIONS

The available literature on the antifungal PK changes in ECMO setting is scarce. Whenever possible, therapeutic drug monitoring is highly advised to personalize antifungal therapy.

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 in adult patients with sepsis and septic shock: Why, how, when, and for whom

Sepsis and septic shock remain the leading causes of death in intensive care units. Some patients with sepsis fail to respond to routine treatment and rapidly progress to refractory respiratory and circulatory failure, necessitating extracorporeal membrane oxygenation (ECMO). However, the role of ECMO in adult patients with sepsis has not been fully established. According to existing studies, ECMO may be a viable salvage therapy in carefully selected adult patients with sepsis. The choice of venovenous, venoarterial, or hybrid ECMO modes is primarily determined by the patient's oxygenation and hemodynamics (distributive shock with preserved cardiac output, septic cardiomyopathy (left, right, or biventricular heart failure), or right ventricular failure caused by acute respiratory distress syndrome). Veno-venous ECMO can be used in patients with sepsis and severe acute respiratory distress syndrome when conventional mechanical ventilation fails, and early application of veno-arterial ECMO in patients with sepsis-induced refractory cardiogenic shock may be critical in improving their chances of survival. When ECMO is indicated, the choice of an appropriate mode and determination of the optimal timing of initiation and weaning are critical, particularly in an experienced ECMO center. Furthermore, some special issues, such as ECMO flow, anticoagulation, and antibiotic therapy, should be noted during the management of ECMO support.

Prone Positioning During Extracorporeal Membrane Oxygenation in Patients With Severe ARDS: The PRONECMO Randomized Clinical Trial

Importance

Prone positioning may improve outcomes in patients with severe acute respiratory distress syndrome (ARDS), but it is unknown whether prone positioning improves clinical outcomes among patients with ARDS who are undergoing venovenous extracorporeal membrane oxygenation (VV-ECMO) compared with supine positioning.

Objective

To test whether prone positioning vs supine positioning decreases the time to successful ECMO weaning in patients with severe ARDS supported by VV-ECMO.

Design, Setting, and Participants

Randomized clinical trial of patients with severe ARDS undergoing VV-ECMO for less than 48 hours at 14 intensive care units (ICUs) in France between March 3, 2021, and December 7, 2021.

Interventions

Patients were randomized 1:1 to prone positioning (at least 4 sessions of 16 hours) (n = 86) or to supine positioning (n = 84).

Main Outcomes and Measures

The primary outcome was time to successful ECMO weaning within 60 days following randomization. Secondary outcomes included ECMO and mechanical ventilation-free days, ICU and hospital length of stay, skin pressure injury, serious adverse events, and all-cause mortality at 90-day follow-up.

Results

Among 170 randomized patients (median age, 51 [IQR, 43-59] years; n = 60 women [35%]), median respiratory system compliance was 15.0 (IQR, 10.7-20.6) mL/cm H2O; 159 patients (94%) had COVID-19-related ARDS; and 164 (96%) were in prone position before ECMO initiation. Within 60 days of enrollment, 38 of 86 patients (44%) had successful ECMO weaning in the prone ECMO group compared with 37 of 84 (44%) in the supine ECMO group (risk difference, 0.1% [95% CI, -14.9% to 15.2%]; subdistribution hazard ratio, 1.11 [95% CI, 0.71-1.75]; P = .64). Within 90 days, no significant difference was observed in ECMO duration (28 vs 32 days; difference, -4.9 [95% CI, -11.2 to 1.5] days; P = .13), ICU length of stay, or 90-day mortality (51% vs 48%; risk difference, 2.4% [95% CI, -13.9% to 18.6%]; P = .62). No serious adverse events were reported during the prone position procedure.

Conclusions and Relevance

Among patients with severe ARDS supported by VV-ECMO, prone positioning compared with supine positioning did not significantly reduce time to successful weaning of ECMO.

Trial Registration

ClinicalTrials.gov Identifier: NCT04607551.

Interaction of ceftazidime and clindamycin with extracorporeal life support

BACKGROUND

Ceftazidime and clindamycin are commonly prescribed to critically ill patients who require extracorporeal life support such as ECMO and CRRT. The effect of ECMO and CRRT on the disposition of ceftazidime and clindamycin is currently unknown.

METHODS

Ceftazidime and clindamycin extraction were studied with ex vivo ECMO and CRRT circuits primed with human blood. The percent recovery of these drugs over time was calculated to determine the degree of interaction between these drugs and circuit components.

RESULTS

Neither ceftazidime nor clindamycin exhibited measurable interactions with the ECMO circuit. In contrast, CRRT cleared 100% of ceftazidime from the experimental circuit within the first 2 h. Clearance of clindamycin from the CRRT circuit was slower, with about 20% removed after 6 h.

CONCLUSION

Clindamycin and ceftazidime dosing adjustments are likely required in patients who are supported with CRRT, and future studies to quantify these adjustments should consider the pathophysiology of the patient in combination with the clearance due to CRRT. Dosing adjustments to account for adsorption to ECMO circuit components are likely unnecessary and should focus instead on the pathophysiology of the patient and changes in volume of distribution. These results will help improve the safety and efficacy of ceftazidime and clindamycin in patients requiring ECMO and CRRT.

SARS-CoV-2-Infected Pregnant Woman Requiring 38 Days of Extracorporeal Membrane Oxygenation Experiences Rectal Ulcer Bleeding: A Case Report

Pregnancy has been shown to be associated with an adverse clinical course and symptomatic patients with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. Extracorporeal membrane oxygenation (ECMO) is rarely used in pregnant or postpartum women with severe coronavirus disease 2019 (COVID-19). Here, we report the rare case of a pregnant woman diagnosed with SARS-CoV-2 infection placed on ECMO postpartum who subsequently received treatment for active rectal ulcer bleeding. Despite being placed on ECMO for 38 days and receiving a massive transfusion of 95 packs of red blood cells, she recovered and was discharged on hospital day 112. ECMO can be used in most patients with severe COVID-19, including pregnant patients, although potential coagulopathy complications must be considered.

Bloodstream infections in COVID-19 patients undergoing extracorporeal membrane oxygenation in ICU: An observational cohort study

BACKGROUND

COVID-19 patients undergoing ECMO are at highly increased risk of nosocomial infections.

OBJECTIVES

To study incidence, clinical outcomes and microbiological features of bloodstream infections (BSI) occurring during ECMO in COVID-19 patients.

METHODS

Observational prospective cohort study enrolling consecutive COVID-19 patients undergoing veno-venous-ECMO in an Italian ICU from March 2020 to March 2022.

RESULTS

In the study population of 68 patients (age 53 [49-60] years, 82% males), 30 (44%) developed bloodstream infections (BSI group) while 38 did not (N-BSI group) with an incidence of 32 events/1000 days of ECMO. In BSI group pre-ECMO respiratory support was shorter (6 [4-9] vs 9 [5-12] days, p = 0.02) and ECMO treatment was longer (18 [10-29] vs 11 [7-18] days, p = 0.03) than in N-BSI group. The overall ECMO and ICU mortality were 50% and 59%, respectively, without any inter-group difference (p = 1.00). A longer ECMO treatment was independently correlated with higher rate of BSI (p = 0.04, OR [95% CI] 1.06 [1.02-1.11]). Sixteen primary and 14 secondary infectious events were documented. Gram-positive pathogens were more common in primary than secondary BSI (88% vs 43%, p = 0.02) and Enterococcus faecalis (56%) was the most frequent one. Conversely, Gram-negative microorganisms were more often isolated in secondary rather than primary BSI (57% vs 13%, p = 0.02), with Acinetobacter baumannii (21%) and Pseudomonas aeruginosa (21%) as most represented species. The administration of Sars-CoV-2 antiviral drug showed independent correlation with a reduced rate of ICU mortality (p = 0.01, OR [95% CI] 0.22 [0.07-0.73]).

CONCLUSIONS

Bloodstream infections represented a frequent complication without worsening clinical outcomes in our COVID-19 patients undergoing ECMO. Primary and secondary BSI events showed peculiar microbiological profiles.

Interrater agreement in classifying infections during extracorporeal membrane oxygenation

Infectious complications are common during extracorporeal membrane oxygenation (ECMO) and may negatively impact outcomes. However, there is considerable variation in the reported rates of incidence, which hampers the use of infections as a quality benchmark for ECMO centers. To assess the contributing role of poor interrater agreement, three independent raters reviewed medical records from all intensive care unit (ICU) patients who received ECMO for >24 h in our tertiary center between October 2019 and October 2021 for suspected episodes of infection, which were rated based on their date of onset and presumed site/diagnosis. To establish a gold standard, any discrepancies were resolved using an expert panel consisting of two intensivists/infectious disease specialists. During 83 ECMO-runs in 77 patients, we observed a total of 62 adjudicated infectious episodes (incidence rate 62, 95% CI: 48-80, per 1000 days at risk). Among 81 episodes suspected by at least one observer, 66 (81%) were identified by two, and only 44 (54%) by all three raters, resulting in Fleiss' kappa of 0.10 (95% CI: 0.00-0.19; slight agreement). However, if raters concurred regarding infection onset, subsequent agreement on infection site was good (concordance 89%; kappa 0.85, 95% CI: 0.72-0.98; near perfect agreement). In conclusion, adjudication of infectious episodes during ECMO is associated with poor interrater agreement regarding occurrence-but not site-of infection. This finding might partially explain the significant disparities observed in reported infection rates during ECMO, emphasizing the need for caution when interpreting infection data in this particular population due to the potential for inherent measurement error.

Extracorporeal membrane oxygenation (ECMO) and beyond in near fatal asthma: A comprehensive review

The treatment of choice in severe asthma exacerbations with respiratory failure includes ventilatory support, both invasive and/or non-invasive, along with different kinds of asthma medication. Of note, the rate of mortality of patients with asthma has decreased substantially in recent years mainly due to significant advances in pharmacological treatment and other management strategies. However, the risk of death in patients with severe asthma who require invasive mechanical ventilation has been estimated between 6.5% and 10.3%. When conventional measures fail, rescue strategies, such as extracorporeal membrane oxygenation (ECMO) or extracorporeal CO2 removal (ECCO2R) may need to be implemented. While ECMO does not constitute a definitive treatment per se, it can minimize further ventilator associated lung injury (VALI) and can enable diagnostic-therapeutic maneuvers that cannot be performed without ECMO such as bronchoscopy and transfer for diagnostic imaging. Asthma is one of the diseases that is associated with excellent outcomes for patients with refractory respiratory failure requiring ECMO support, as shown by the Extracorporeal Life Support Organization (ELSO) registry. Moreover, in such situations, the use of ECCO2R for rescue has been described and utilized in both children and adults and is more widely spread in different hospitals than ECMO. In this article, we aim to review the evidence for the usefulness of extracorporeal respiratory support measures in the management of severe asthma exacerbations that lead to respiratory failure.

Prevalence and Impact of Infection during Extracorporeal Membrane Oxygenation in Oncologic Patients: A Retrospective Analysis of the Extracorporeal Life Support Organization (ELSO) Registry

Background: Extracorporeal membrane oxygenation (ECMO) is widely utilized for severe cardiopulmonary insufficiency, but its application to the oncologic population has been debated given concern for increased risk of infection. This study aims to analyze the implications of infections acquired during ECMO runs in patients with malignancy. Methods: The Extracorporeal Life Support Organization (ELSO) database was queried for patients with an International Classification of Diseases code of neoplasms over the last two decades (2000-2019). Culture-proven infections during ECMO runs were analyzed and compared to previously reported data for all ECMO runs. Results: Two thousand, seven hundred and fifty-seven patients met inclusion criteria. Infection acquired during ECMO run was found in 687 patients, a significantly greater proportion compared to all ECMO runs (24.9% vs 11.7%; P = .001). Adult patients had a significantly higher rate of infection (27.0%; P < .001) compared to neonatal (11.0%) and pediatric (21.4%) patients. Prevalence of infection was highest in pulmonary ECMO (29.0%), while the infection rate standardized with ECMO duration was highest in extracorporeal cardiopulmonary resuscitation (55.03/1000-day ECMO run). Compared with ECMO for all diagnoses, the prevalence of Candida and Klebsiella infection was significantly higher in adult and pediatric oncologic patients. Regardless of the pathogen, the presence of infection was not associated with lower survival (38.6% vs 40.0%; P = .522). Conclusions: Oncologic patients had a significantly higher infection rate while on ECMO compared with the general ECMO population. However, the prognostic impact of these infections was minimal, thus ECMO should not be withheld in oncologic patients solely with concern for infection.

The Influence of Extracorporeal Membrane Oxygenation on Antibiotic Pharmacokinetics

Extracorporeal membrane oxygenation (ECMO) is becoming increasingly utilized to support critically ill patients who experience life-threatening cardiac or pulmonary compromise. The provision of this intervention poses challenges related to its complications and the optimization of medication therapy. ECMO's mechanical circulatory support is facilitated via various devices and equipment that have been shown to sequester lipophilic- and protein-bound medications, including anti-infectives. Since infectious outcomes are dependent on achieving specific anti-infectives' pharmacodynamic targets, the understanding of these medications' pharmacokinetic parameters in the setting of ECMO is important to clinicians. This narrative, non-systematic review evaluated the findings of the most recent and robust pharmacokinetic analyses for commonly utilized anti-infectives in the setting of ECMO. The data from available literature indicates that anti-infective pharmacokinetic parameters are similar to those observed in other non-ECMO critically ill populations, but considerable variability in the findings was observed between patients, thus prompting further evaluation of therapeutic drug monitoring in this complex population.

First nosocomial infections in children supported by veno-arterial extracorporeal membrane oxygenation (VA-ECMO)

BACKGROUND

Veno-arterial Extracorporeal Membrane Oxygenation (VA-ECMO) is a standard procedure for patient with refractory shock in Pediatric Intensive Care Unit (PICU). There is a paucity of data on the time relationship between VA-ECMO support, nosocomial infection occurrence, and PICU length of stay (LOS). The aim of this study was to determine the characteristics and impact of ECMO-related infections.

METHODS

This is a retrospective study from 01/2008 to 12/2014, enrolling children with a VA-ECMO support for > 6 h. We recorded the first PICU infection during the VA-ECMO run, defined as a positive microbiological sample with clinical signs of infection or clinical signs of severe infection without positive sample.

RESULTS

During the study period, 41 patients (25/41 male) were included, with a median age of 41.2 months (IQR 12.9-89.9) and a 53% mortality rate. Median time on VA-ECMO was 4.2 d (IQR 2-7.1), median PICU LOS was 14.7 d (IQR 4,7-26,9). Overall, 34% patients developed an infection, with an incidence of 60/1000 VA-ECMO days. Median time to first infection was 4 d (IQR 3-5), with Pseudomonas spp. being the most commonly detected microorganism (42%). Infected sites were ventilator-associated pneumonia (9/14), sternotomy infection (2/14), bloodstream (2/14) and urinary tract infections (1/14). Longer VA-ECMO support (> 5 d) (OR 5.9 (CI 95% 1.4-24.6; p = 0.01) and longer PICU stay (> 14 d) (OR 12 (95% CI 2.2-65.5; p = 0.004) were associated with infection.

CONCLUSION

In this single-center study, we underlined the high proportion and early occurrence of infections in patient on VA-ECMO, mostly in the first week. As infection was an early event, it may prolong the duration of VA-ECMO support and PICU LOS. Further research is needed to better understand the impact of infections on VA-ECMO and develop prevention strategies.

Complications Associated With Venovenous Extracorporeal Membrane Oxygenation-What Can Go Wrong?

OBJECTIVES

Despite increasing use and promising outcomes, venovenous extracorporeal membrane oxygenation (V-V ECMO) introduces the risk of a number of complications across the spectrum of ECMO care. This narrative review describes the variety of short- and long-term complications that can occur during treatment with ECMO and how patient selection and management decisions may influence the risk of these complications.

DATA SOURCES

English language articles were identified in PubMed using phrases related to V-V ECMO, acute respiratory distress syndrome, severe respiratory failure, and complications.

STUDY SELECTION

Original research, review articles, commentaries, and published guidelines from the Extracorporeal Life support Organization were considered.

DATA EXTRACTION

Data from relevant literature were identified, reviewed, and integrated into a concise narrative review.

DATA SYNTHESIS

Selecting patients for V-V ECMO exposes the patient to a number of complications. Adequate knowledge of these risks is needed to weigh them against the anticipated benefit of treatment. Timing of ECMO initiation and transfer to centers capable of providing ECMO affect patient outcomes. Choosing a configuration that insufficiently addresses the patient's physiologic deficit leads to consequences of inadequate physiologic support. Suboptimal mechanical ventilator management during ECMO may lead to worsening lung injury, delayed lung recovery, or ventilator-associated pneumonia. Premature decannulation from ECMO as lungs recover can lead to clinical worsening, and delayed decannulation can prolong exposure to complications unnecessarily. Short-term complications include bleeding, thrombosis, and hemolysis, renal and neurologic injury, concomitant infections, and technical and mechanical problems. Long-term complications reflect the physical, functional, and neurologic sequelae of critical illness. ECMO can introduce ethical and emotional challenges, particularly when bridging strategies fail.

CONCLUSIONS

V-V ECMO is associated with a number of complications. ECMO selection, timing of initiation, and management decisions impact the presence and severity of these potential harms.

The Use of ECMO for COVID-19: Lessons Learned

The coronavirus disease 2019 (COVID-19) pandemic has seen an increase in global cases of severe acute respiratory distress syndrome (ARDS), with a concomitant increased demand for extracorporeal membrane oxygenation (ECMO). Outcomes of patients with severe ARDS due to COVID-19 infection receiving ECMO support are evolving. The need for surge capacity, practical and ethical limitations on implementing ECMO, and the prolonged duration of ECMO support in patients with COVID-19-related ARDS has revealed limitations in organization and resource utilization. Coordination of efforts at multiple levels, from research to implementation, resulted in numerous innovations in the delivery of ECMO.

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.

Risk factors for bloodstream infection (BSI) in patients with severe acute respiratory distress syndrome (ARDS) supported by veno-venous extracorporeal membrane oxygenation (VV-ECMO)

Background

There were relatively few studies about the incidence and risk factors for bloodstream infection (BSI) in patients with severe acute respiratory distress syndrome (ARDS) supported by veno–venous extracorporeal membrane oxygenation (VV–ECMO).

Methods

Patients who were diagnosed with severe ARDS and received VV–ECMO treatment in the medical intensive care unit of China–Japan Friendship Hospital from August 2013 to March 2019 were retrospectively studied. The pathogens isolated from blood culture (BC) were identified and analyzed for drug sensitivity. The risk factors for BSI were analyzed by logistic regression.

Results

A total of 105 patients were included in this single–center retrospective cohort study. Among them, 23 patients (22%) had BSIs. 19 cases were identified as primary BSI; while the other 4 cases were as secondary BSI. A total of 23 pathogenic strains were isolated from BCs, including gram–negative (G^–) bacilli in 21 (91%) cases, gram–positive (G⁺) cocci in 1 case, fungus in 1 case, and multidrug–resistant (MDR) organisms in 8 cases. Compared with patients without BSI, patients with BSI had a higher Murray score (odds ratio = 6.29, P = 0.01) and more blood transfusion (odds ratio = 1.27, P = 0.03) during ECMO.

Conclusions

The incidence of BSI in patients with severe ARDS supported by VV–ECMO was 22%. G^– bacilli was the main pathogen, and most of them were MDR–G^– bacilli (MDR–GNB). Higher Murray score and more blood transfusion may be the independent risk factors for BSI.

Veno-venous Extracorporeal Membrane Oxygenation for pregnant women with Acute Respiratory Distress Syndrome: a narrative review

Acute respiratory distress syndrome remains an uncommon condition during pregnancy. In patients with severe acute respiratory distress syndrome, when oxygenation or ventilation cannot be supported sufficiently using best practice conventional mechanical ventilation and additional therapies, veno-venous extracorporeal membrane oxygenation may be considered. In the past two decades, there has been increasing adoption of this technique to support adult patients with refractory acute respiratory distress syndrome. However, its use for the management of pregnant women is rare and remains a challenge. This narrative review addresses acute respiratory distress syndrome and its management during pregnancy, and then focuses on indications, contraindications, challenges, potential complications, and outcomes of the use of veno-venous extracorporeal membrane oxygenation for acute respiratory distress syndrome in the pregnant patient.

Outcome and Clinical Characteristics of Nosocomial Infection in Adult Patients Undergoing Extracorporeal Membrane Oxygenation: A Systematic Review and Meta-Analysis

Objective

This study conducts a meta-analysis of clinical outcomes of nosocomial infection in adult patients receiving extracorporeal membrane oxygenation (ECMO) and systematically evaluates clinical epidemiological characteristics.

Methods

Document retrieval strategies were determined, and all adult patients treated by ECMO were included. The prevalence, incidence, mortality, ECMO use time, intensive care unit (ICU) stay time, hospital stay time, and risk factors of nosocomial infection were systematically evaluated. Subsequently, a meta-analysis of the impact of nosocomial infection on risk of in-hospital mortality was conducted.

Results

A total of 25 retrospective studies were included, and 19 studies were included in the meta-analysis. The prevalence of nosocomial infection was 8.8–64.0%, incidence was 1.7–85.4‰ (per 1,000 ECMO days), and in-hospital mortality was 31.5–75.4%. The duration of ECMO usage and length of ICU stay were longer for infected patients. Compared with non-infected patients, the meta-analysis revealed that nosocomial infection increased the relative risk of death of adult patients receiving ECMO by 32%. The risk factors included the duration of ECMO usage and disease severity score.

Conclusions

Adult patients treated by ECMO have high prevalence of nosocomial infection. In addition, their ECMO use time and ICU stays are longer. Nosocomial infection significantly increases the relative risk of in-hospital mortality.

Extracorporeal Membrane Oxygenation during Respiratory Pandemics: Past, Present, and Future

The role of extracorporeal membrane oxygenation (ECMO) in the management of severe acute respiratory failure, including acute respiratory distress syndrome, has become better defined in recent years in light of emerging high-quality evidence and technological advances. Use of ECMO has consequently increased throughout many parts of the world. The coronavirus disease (COVID-19) pandemic, however, has highlighted deficiencies in organizational capacity, research capability, knowledge sharing, and resource use. Although governments, medical societies, hospital systems, and clinicians were collectively unprepared for the scope of this pandemic, the use of ECMO, a highly resource-intensive and specialized form of life support, presented specific logistical and ethical challenges. As the pandemic has evolved, there has been greater collaboration in the use of ECMO across centers and regions, together with more robust data reporting through international registries and observational studies. Nevertheless, centralization of ECMO capacity is lacking in many regions of the world, and equitable use of ECMO resources remains uneven. There are no widely available mechanisms to conduct large-scale, rigorous clinical trials in real time. In this critical care review, we outline lessons learned during COVID-19 and prior respiratory pandemics in which ECMO was used, and we describe how we might apply these lessons going forward, both during the ongoing COVID-19 pandemic and in the future.

Extracorporeal Membrane Oxygenation Cannula-Related Infections: Epidemiology and Risk Factors

Although being a potential major source of infection in extracorporeal membrane oxygenation (ECMO) patients, data regarding cannula-related infections (CRI) remain scarce. We therefore aimed at describing the epidemiology of CRI among critically ill patients supported by ECMO. Between October 2017 and November 2019, adult patients supported by either venoarterial (VA), venopulmonary arterial, or venovenous (VV) ECMO for more than 24 hours were prospectively enrolled. When CRI was suspected, cannula swab and subcutaneous needle aspirate samples were obtained for microbiological culture. Cannula tips were systematically sent for culture at the time of ECMO removal. Primary end-point was CRI, which was defined by sepsis or local sign of cannula infection and at least one positive culture among swab, subcutaneous needle aspirate or tip. Multivariate analysis was performed to identify risk factors of CRI. Hundred patients were included, including 77 VA, 12 venopulmonary arterial, and 11 VV ECMO. Cannula-related infections were diagnosed after a median duration of ECMO of 10 [7-13] days. Rate of CRI was 24%, including 10% with bacteremia. Most frequent involved pathogens were Enterobacteriaceae (n = 14), Enterococci (n = 8), and coagulase-negative Staphylococci (n = 7). By multivariate analysis, diabetes and ECMO duration were independently associated with CRI.

Cause of In-Hospital Death After Weaning from Venoarterial-Extracorporeal Membrane Oxygenation

PURPOSE

A survival gap between weaning from venoarterial-extracorporeal membrane oxygenation (VA-ECMO) and the hospital discharge has been consistently reported. The aim of this study is to investigate the clinical features of patients who underwent successful VA-ECMO decannulation at our institution and to identify the major contributors responsible for adverse outcomes.

METHODS

We retrospectively reviewed all patients supported with VA-ECMO in our institution between January 2013 and June 2020. Only patients that survived VA-ECMO and underwent successful decannulation were included and dichotomized based on survival to hospital discharge: non-survivors versus survivors. The primary study outcome was the cause of death after successful VA-ECMO decannulation.

RESULTS

Of the 262 adult patients who underwent VA-ECMO decannulation, 72 (27.5%) patients did not survive to hospital discharge. Non-survivors were older (62 vs. 54 years, p < 0.001) and suffering from many pre-existing comorbidities. Pneumonia and sepsis were the most frequent infectious complication and almost twice as likely in non-survivors. Major causes of death were: cardiovascular (31.9%), infections (25.0%) and neurological (20.8%). The survival curve demonstrated that 51.4% of our patients died within 8 days after decannulation. Multivariate analysis identified older age, central venous cannulation, pulmonary bleeding and infection, dialysis after VA-ECMO, sepsis, and ischemic stroke (OR = 7.86, 95% CI: 2.76-2.43, p < 0.001) as factors significantly predisposing to patients' death.

CONCLUSION

In our study, one-third of patients decannulated off VA-ECMO did not survive to hospital discharge due to end-stage heart failure, infections or neurological injury. The first 8 post-decannulation days were recognized as a critical period where thorough strategies to prevent acquired infections and cautious support of end-organ function should be warranted. Future large-scale trials are needed to confirm our results.

Perinatal outcomes of pregnant women with severe COVID-19 requiring extracorporeal membrane oxygenation (ECMO): a case series and literature review

Purpose

Pregnant women with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have a higher risk of hospitalization, admission to intensive care unit (ICU) and invasive ventilation, and of acute respiratory distress syndrome (ARDS). In case of ARDS and critical severe coronavirus disease 2019 (COVID-19), the use of extracorporeal membrane oxygenation (ECMO) is recommended when other respiratory support strategies (oxygen insufflation, non-invasive ventilation [NIV], invasive ventilation through an endotracheal tube) are insufficient. However, available data on ECMO in pregnant and postpartum women with critical COVID-19 are very limited.

Methods

A case series of three critically ill pregnant women who required ECMO support for COVID-19 in pregnancy and/or in the postpartum period.

Results

The first patient tested positive for COVID-19 during the second trimester, she developed ARDS and required ECMO for 38 days. She was discharged in good general conditions and a cesarean-section [CS] at term was performed for obstetric indication. The second patient developed COVID-19-related ARDS at 28 weeks of gestation. During ECMO, she experienced a precipitous vaginal delivery at 31 weeks and 6 days of gestation. She was discharged 1 month later in good general conditions. The third patient, an obese 43-year-old woman, tested positive at 38 weeks and 2 days of gestation. Because of the worsening of clinical condition, a CS was performed, and she underwent ECMO. 143 days after the CS, she died because of sepsis and multiple organ failure (MOF). Thrombosis, hemorrhage and infections were the main complications among our patients. Neonatal outcomes have been positive.

Conclusion

ECMO should be considered a life-saving therapy for pregnant women with severe COVID-19.

Neutrophil dysfunction due to continuous mechanical shear exposure in mechanically assisted circulation in vitro

OBJECTIVE

Leukocytes play an important role in the body's immune system. The aim of this study was to assess alterations in neutrophil phenotype and function in pump-assisted circulation in vitro.

METHODS

Human blood was circulated for four hours in three circulatory flow loops with a CentriMag blood pump operated at a flow of 4.5 L/min at three rotational speeds (2100, 2800, and 4000 rpm), against three pressure heads (75, 150, and 350 mm Hg), respectively. Blood samples were collected hourly for analyses of neutrophil activation state (Mac-1, CD62L, CD162), neutrophil reactive oxygen species (ROS) production, apoptosis, and neutrophil phagocytosis.

RESULTS

Activated neutrophils indicated by both Mac-1 expression and decreased surface expression of CD62L and CD162 receptors increased with time in three loops. The highest level of neutrophil activation was observed in the loop with the highest rotational speed. Platelet-neutrophil aggregates (PNAs) progressively increased in two loops with lower rotational speeds. PNAs peaked at one hour after circulation and decreased subsequently in the loop with the highest rotational speed. Neutrophil ROS production dramatically increased at one hour after circulation and decreased subsequently in all three loops with similar levels and trends. Apoptotic neutrophils increased with time in all three loops. Neutrophil phagocytosis capacity in three loops initially elevated at one hour after circulation and decreased subsequently. Apoptosis and altered phagocytosis were dependent on rotational speed.

CONCLUSIONS

Our study revealed that the pump-assisted circulation induced neutrophil activation, apoptosis, and functional impairment. The alterations were strongly associated with pump operating condition and duration.

Multiple Secondary Healthcare-Associated Infections Due to Carbapenem-Resistant Organisms in a Critically Ill COVID-19 Patient on Extensively Prolonged Venovenous Extracorporeal Membrane Oxygenation Support-A Case Report

Patients with severe Coronavirus disease 2019 (COVID-19) are at high risk for secondary infection with multidrug-resistant organisms (MDROs). Secondary infections contribute to a more severe clinical course and longer intensive care unit (ICU) stays in patients with COVID-19. A man in his 60s was admitted to the ICU at a university hospital for severe COVID-19 pneumonia requiring mechanical ventilation. His respiratory condition worsened further due to persistent bacteremia caused by imipenem-non-susceptible Klebsiella aerogenes and he required VV-ECMO. Subsequently, he developed a catheter-related bloodstream infection (CRBSI) due to Candida albicans, ventilator-associated pneumonia (VAP) due to multidrug-resistant Pseudomonas aeruginosa (MDRP), and a perianal abscess due to carbapenem-resistant K. aerogenes despite infection control procedures that maximized contact precautions and the absence of MDRO contamination in the patient’s room environment. He was decannulated from VV-ECMO after a total of 72 days of ECMO support, and was eventually weaned off ventilator support and discharged from the ICU on day 138. This case highlights the challenges of preventing, diagnosing, and treating multidrug-resistant organisms and healthcare-associated infections (HAIs) in the critical care management of severe COVID-19. In addition to the stringent implementation of infection prevention measures, a high index of suspicion and a careful evaluation of HAIs are required in such patients.

Endotoxin Activity in Patients With Extracorporeal Membrane Oxygenation Life Support: An Observational Pilot Study

Background: Extracorporeal membrane oxygenation (ECMO) life support has become an integral part of intensive care. The endotoxin activity assay (EAA) is a useful test to measure endotoxemia severity in whole blood. To date, no information is available regarding the EAA levels and their effect on clinical outcomes in critically ill patients with ECMO support.

Methods: This prospective observational pilot study enrolled adult critically ill patients with ECMO support from August 2019 to December 2020. The EAA levels were measured within 24 h (T1), and at 25–48 (T2), 49–72 (T3), and 73–96 h (T4) after ECMO initiation. This study primarily aimed to investigate the incidence of high EAA levels (≥0.6) at each time point. Subsequent exploratory analyses were conducted to compare the EAA levels of venoarterial ECMO (VA-ECMO) patients between 30-day survivors and non-survivors. Post-hoc analysis was performed to compare the clinical outcomes of VA-ECMO patients with elevated EAA levels at T3 (vs. T1) and those without elevated EAA levels.

Results: A total of 39 VA-ECMO patients and 15 venovenous ECMO (VV-ECMO) patients were enrolled. At T1, the incidence of high EAA level (≥0.6) was 42% in VV-ECMO patients and 9% in VA-ECMO patients (P = 0.02). At T2, the incidence of high EAA level was 40% in VV-ECMO patients and 5% in VA-ECMO patients (P = 0.005). In VA-ECMO patients, EAA levels at T3 were significantly higher in 30-day non-survivors than in survivors (median [interquartile range]: 0.49 [0.37–0.93] vs. 0.31 [0.19–0.51], median difference 0.16 [95% confidence interval [CI], 0.02–0.31]; P = 0.024). Moreover, VA-ECMO patients with elevated EAA levels at T3 (vs. T1) had lower 30-day survival than patients without elevated EAA levels (39 vs. 83%, P = 0.026) and fewer ECMO free days by day 30 (median: 3 vs. 23 days, median difference 12 days [95% CI, 0–22]; P = 0.028).

Conclusions: A certain proportion of patients experienced high EAA levels (≥0.6) after VV-ECMO or VA-ECMO initiation. VA-ECMO patients with an elevated EAA level at 49–72 h were associated with poor clinical outcomes.

Long-term survival and health-related quality of life in patients with severe acute respiratory distress syndrome and veno-venous extracorporeal membrane oxygenation support

Background

There is limited information about the long-term outcome of patients suffering from acute respiratory distress syndrome (ARDS) supported with veno-venous extracorporeal membrane oxygenation (VV ECMO). Most studies focused on short- to mid-term follow-up. We aimed to investigate long-term survival and health-related quality of life (HRQL) in these patients.

Methods

We report retrospective data from a single-centre registry of patients with severe ARDS treated with VV ECMO at the Interdisciplinary Medical Intensive Care Unit at the Medical Centre, University of Freiburg, Germany, between 10/2010 and 06/2019. Follow-up data of all patients that survived the index hospitalisation were collected by telephone interviews from 02/2020 till 09/2020. Long-term survival, HRQL (Short-Form Health Survey-36 (SF-36), St. Georges Respiratory Questionnaire (SGRQ), Hospital Anxiety and Depression Scale (HADS)) and the return to work rate were documented.

Results

In total, 289 patients were treated with VV ECMO during the study period (median age 55 years, 67% males, hospital survival 45%). After a median duration of 3.9 years, follow-up assessment was complete in 94 of 129 hospital survivors (73%). Fifty-three patients completed the HRQL assessment. Hospital survivors showed a high 6- and 12-month survival rate (89% and 85%, respectively). Estimated survival rate of those discharged alive from ICU was 68.5% (95%-CI 56.9–80.1%) after 9.7 years. These patients reported high levels of HRQL (median SF-36 total score 73) and only few pulmonary (median SGRQ total score 19) and mental limitations (median HAD-D score 2 and HAD-A score 3). In total, 80% of the patients were able to resume employment.

Conclusion

This analysis of VV ECMO patients showed favourable long-term survival and high levels of HRQL suggesting promising prospects for VV ECMO survivors.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03821-0.

Candidaemia incidence in prolonged veno-venous extracorporeal membrane oxygenation

This single-centre retrospective study reports the dynamics of candida bloodstream infection (CBSI) incidence in 145 patients receiving venovenous ECMO for respiratory support, between January 2014 and December 2018. Incidence rate and odds ratio (OR) of CBSI were calculated, stratified by week of ECMO exposure. Weekly incidence increased throughout the ECMO run, with a rising trend in OR (P = 0.005), and a window of continued risk after decannulation was observed. Of the 13 patients that developed CBSI, five (38%) received empirical micafungin treatment before positive culture due to clinical suspicion. Prospective studies, aiming to improve ECMO diagnostic stewardship practices and discourage antifungal prophylaxis or empiric management where unnecessary, are needed.

Diagnostic yield of routine daily blood culture in patients on veno-arterial extracorporeal membrane oxygenation

BACKGROUND

Bloodstream infections (BSIs) are frequent on veno-arterial extracorporeal membrane oxygenation (V-A ECMO). Performing routine blood cultures (BCs) may identify early paucisymptomatic BSIs. We investigated the contribution of systematic daily BCs to detect BSIs on V-A ECMO.

METHODS

This was a retrospective study including all adult patients requiring V-A ECMO and surviving more than 24 h. Our protocol included routine daily BCs, from V-A ECMO insertion up to 5 days after withdrawal; other BCs were performed on-demand.

RESULTS

On the 150 V-A ECMO included, 2146 BCs were performed (1162 routine and 984 on-demand BCs); 190 (9%) were positive, including 68 contaminants. Fifty-one (4%) routine BCs revealed BSIs; meanwhile, 71 (7%) on-demand BCs revealed BSIs (p = 0.005). Performing routine BCs was negatively associated with BSIs diagnosis (OR 0.55, 95% CI [0.38; 0.81], p = 0.002). However, 16 (31%) BSIs diagnosed by routine BCs would have been missed by on-demand BCs. Independent variables for BSIs diagnosis after routine BCs were: V-A ECMO for cardiac graft failure (OR 2.43, 95% CI [1.20; 4.92], p = 0.013) and sampling with on-going antimicrobial therapy (OR 2.15, 95% CI [1.08; 4.27], p = 0.029) or renal replacement therapy (OR 2.05, 95% CI [1.10; 3.81], p = 0.008). Without these three conditions, only two BSIs diagnosed with routine BCs would have been missed by on-demand BCs sampling.

CONCLUSIONS

Although routine daily BCs are less effective than on-demand BCs and expose to contamination and inappropriate antimicrobial therapy, a policy restricted to on-demand BCs would omit a significant proportion of BSIs. This argues for a tailored approach to routine daily BCs on V-A ECMO, based on risk factors for positivity.

Pharmacokinetics of Commonly Used Antimicrobials in Critically Ill Adults During Extracorporeal Membrane Oxygenation: A Systematic Review

PURPOSE

Adequate dosing of antimicrobials is critical to properly treat infections and limit development of resistance and adverse effects. Limited guidance exists for antimicrobial dosing adjustments in patients requiring extracorporporeal membrane oxygenation (ECMO) therapy. A systematic review was conducted to delineate the pharmacokinetics (PK) and pharmacodynamics (PD) of antimicrobials in critically ill adult patients requiring ECMO.

METHODS

Medline, EMBASE, Global Health, and All EBM Reviews databases were searched. Grey literature was examined. All studies reporting PK/PD parameters of antimicrobials in critically ill adults treated with ECMO were included, except for case reports and congress abstracts. Ex vivo studies were included. Two independent reviewers applied the inclusion and exclusion criteria. Reviewers were then paired to independently abstract data and evaluate methodological quality of studies using the ROBINS-I tool and the compliance with ClinPK guidelines. Patients' and studies' characteristics, key PK/PD findings, details of ECMO circuits and co-treatments were summarized qualitatively. Dosing recommendations were formulated based on data from controlled studies.

RESULTS

Thirty-two clinical studies were included; most were observational and uncontrolled. Fourteen ex vivo studies were analysed. Information on patient characteristics and co-treatments was often missing. The effect of ECMO on PK/PD parameters of antimicrobials varied depending on the studied drugs. Few dosing recommendations could be formulated given the lack of good quality data.

CONCLUSION

Limited data exist on the PK/PD of antimicrobials during ECMO therapy. Rigorously designed and well powered populational PK studies are required to establish empiric dosing guidelines for antimicrobials in patients requiring ECMO support.

PROSPERO REGISTRATION NUMBER

CRD42018099992 (Registered: July 24th 2018).

Meropenem Pharmacokinetics and Target Attainment in Critically Ill Patients Are Not Affected by Extracorporeal Membrane Oxygenation: A Matched Cohort Analysis

Existing evidence is inconclusive whether meropenem dosing should be adjusted in patients receiving extracorporeal membrane oxygenation (ECMO). Therefore, the aim of this observational matched cohort study was to evaluate the effect of ECMO on pharmacokinetic (PK) variability and target attainment (TA) of meropenem. Patients admitted to the intensive care unit (ICU) simultaneously treated with meropenem and ECMO were eligible. Patients were matched 1:1, based on renal function and body weight, with non-ECMO ICU patients. Meropenem blood sampling was performed over one or two dosing intervals. Population PK modelling was performed using NONMEM7.5. TA was defined as free meropenem concentrations >2 or 8 mg/L (i.e., 1 or 4× minimal inhibitory concentration, respectively) throughout the whole dosing interval. In total, 25 patients were included, contributing 27 dosing intervals. The overall TA was 56% and 26% for the 2 mg/L and 8 mg/L target, respectively. Population PK modelling identified estimated glomerular filtration rate according to the Chronic Kidney Disease Epidemiology equation and body weight, but not ECMO, as significant predictors. In conclusion, TA of meropenem was confirmed to be poor under standard dosing in critically ill patients but was not found to be influenced by ECMO. Future studies should focus on applying dose optimisation strategies for meropenem based on renal function, regardless of ECMO.

Tissue adhesives for bacterial inhibition in extracorporeal membrane oxygenation cannulae

BACKGROUND

One of the most serious complications of extracorporeal membrane oxygenation (ECMO) therapy is ECMO cannulae infection, which can occur at quadruple the rate of central venous catheter infections, and significantly impact morbidity and paediatric mortality. The objective of this in vitro observational study was to assess antimicrobial properties of two n-butyl-2-octyl cyanoacrylate tissue adhesive (TA) formulations for bacterial inhibition at peripheral ECMO cannulae insertion sites.

METHODS

Antimicrobial properties were assessed using modified agar disk-diffusion (n = 3) and simulated agar cannulation insertion site (n = 20) models. Both assays used Staphylococcus epidermidis which was seeded at the edge of the TA or dressing. Microorganism inhibition was visually inspected and evidenced by the presence or absence of a TA bacterial inhibition zone at 24 and 72 h.

RESULTS

Both TAs provided effective barriers to bacterial migration under cannula dressings, to cannula insertion sites and down cannula tunnels. Additionally, both TAs demonstrated distinct zones of inhibition produced when left to polymerise onto agar plates seeded with S. epidermidis.

CONCLUSIONS

N-Butyl-2-octyl cyanoacrylate TA appears to inhibit bacterial growth and migration of S. epidermidis. Application of TA to cannulae insertion sites may therefore be a potential bedside strategy for infection prevention in ECMO cannulae, but requires further testing before being used clinically for this purpose.

Different characteristics of bloodstream infection during venoarterial and venovenous extracorporeal membrane oxygenation in adult patients

Currently, there is scarcity of data on whether differences exist in clinical characteristics and outcomes of bloodstream infection (BSI) between venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO) and whether they differ between Candida BSI and bacteremia in adult ECMO patients. We retrospectively reviewed data of patients who required ECMO for > 48 h and had BSIs while receiving ECMO between January 2015 and June 2020. Cases with a positive blood culture result within 24 h of ECMO implantation were excluded. We identified 94 (from 64 of 194 patients) and 38 (from 17 of 56 patients) BSI episodes under VA and VV ECMO, respectively. Fifty nine BSIs of VA ECMO (59/94, 62.8%) occurred in the first 2 weeks after ECMO implantation, whereas 24 BSIs of VV ECMO (24/38, 63.2%) occurred after 3 weeks of ECMO implantation. Gram-negative bacteremia (39/59, 66.1%) and gram-positive bacteremia (10/24, 41.7%) were the most commonly identified BSI types in the first 2 weeks after VA ECMO implantation and after 3 weeks of VV implantation, respectively. Timing of Candida BSI was early (6/11, 54.5% during the first 2 weeks) in VA ECMO and late (6/9, 66.7% after 3 weeks of initiation) in VV ECMO. Compared with bacteremia, Candida BSI showed no differences in clinical characteristics and outcomes during VA and VV ECMO, except the significant association with prior exposure to carbapenem in VA ECMO (vs. gram-negative bacteremia [P = 0.006], vs. gram-positive bacteremia [P = 0.03]). Our results suggest that ECMO modes may affect BSI clinical features and timing. In particular, Candida BSI occurrence during the early course of VA ECMO is not uncommon, especially in patients with prior carbapenem exposure; however, it usually occurs during the prolonged course of VV ECMO. Consequently, routine blood culture surveillance and empiric antifungal therapy might be warranted in targeted populations of adult ECMO patients, regardless of levels of inflammatory markers and severity scores.

Efficacy of Prophylactic Antibiotics during Extracorporeal Membrane Oxygenation: A Nationwide Cohort Study

RATIONALE

Extracorporeal membrane oxygenation (ECMO) is widely used worldwide, and many hospitals consider using antibiotics to prevent nosocomial infection in ECMO patients. However, the efficacy of antimicrobial prophylaxis for patients receiving ECMO remains unclear.

OBJECTIVE

This study aimed to evaluate the efficacy of prophylactic antibiotics for ECMO patients.

METHODS

This retrospective cohort study was performed using data recorded in the Japanese Diagnosis Procedure Combination database from July 1, 2010, to March 31, 2017. We compared in-hospital mortality, nosocomial pneumonia, acute kidney injury, and diarrhea between patients receiving prophylactic antibiotics (prophylaxis group) and those not receiving antibiotics (control group) using propensity score matching, multivariable logistic regression models fitted using generalized estimating equation, stabilized inverse probability of treatment weighting, and instrumental variable analysis.

RESULTS

We identified 9615 eligible patients and classified them into the prophylaxis (n = 5552) and control (n = 4063) groups. In the propensity score-matched analysis, 3650 pairs were generated. Significant differences between the prophylaxis group and the control group were detected in in-hospital mortality (56.4% vs 59.8%, risk difference: -3.7%, 95% confidence interval [CI]: -6.0 to -1.3) and nosocomial pneumonia (12.9% vs. 15.3%, risk difference: -2.4%, 95% CI: -4.3 to -0.6). In the multivariable logistic regression models fitted using generalized estimating equation, stabilized inverse probability of treatment weighting, and instrumental variable analysis, the point estimates a suggested similar direction to that found in the propensity score analysis. The proportions of patients with acute kidney injury or diarrhea did not significantly increase with the use of prophylactic antibiotics.

CONCLUSION

Using prophylactic antibiotics during ECMO was associated with reduced in-hospital mortality and lower proportions of patients with nosocomial pneumonia. Future prospective studies are needed to validate these results.

Infectious complications associated with short-term mechanical circulatory support in urgent heart transplant candidates

INTRODUCTION AND OBJECTIVES

Short-term mechanical circulatory support is frequently used as a bridge to heart transplant in Spain. The epidemiology and prognostic impact of infectious complications in these patients are unknown.

METHODS

Systematic description of the epidemiology of infectious complications and analysis of their prognostic impact in a multicenter, retrospective registry of patients treated with short-term mechanical devices as a bridge to urgent heart transplant from 2010 to 2015 in 16 Spanish hospitals.

RESULTS

We studied 249 patients, of which 87 (34.9%) had a total of 102 infections. The most frequent site was the respiratory tract (n=47; 46.1%). Microbiological confirmation was obtained in 78 (76.5%) episodes, with a total of 100 causative agents, showing a predominance of gram-negative bacteria (n=58, 58%). Compared with patients without infection, those with infectious complications showed higher mortality during the support period (25.3% vs 12.3%, P=.009) and a lower probability of receiving a transplant (73.6% vs 85.2%, P=.025). In-hospital posttransplant mortality was similar in the 2 groups (with infection: 28.3%; without infection: 23.4%; P=.471).

CONCLUSIONS

Patients supported with temporary devices as a bridge to heart transplant are exposed to a high risk of infectious complications, which are associated with higher mortality during the organ waiting period.

Outcomes of severe systemic rheumatic disease patients requiring extracorporeal membrane oxygenation

BACKGROUND

Systemic rheumatic diseases (SRDs) are a group of inflammatory disorders that can require intensive care unit (ICU) admission because of multiorgan involvement with end-organ failure(s). Critically ill SRD patients requiring extracorporeal membrane oxygenation (ECMO) were studied to gain insight into their characteristics and outcomes.

METHODS

This French monocenter, retrospective study included all SRD patients requiring venovenous (VV)- or venoarterial (VA)-ECMO admitted to a 26-bed ECMO-dedicated ICU from January 2006 to February 2020. The primary endpoint was in-hospital mortality.

RESULTS

Ninety patients (male/female ratio: 0.5; mean age at admission: 41.6 ± 15.2 years) admitted to the ICU received VA/VV-ECMO, respectively, for an SRD-related flare (n = 69, n = 38/31) or infection (n = 21, n = 10/11). SRD was diagnosed in-ICU for 31 (34.4%) patients. In-ICU and in-hospital mortality rates were 48.9 and 51.1%, respectively. Nine patients were bridged to cardiac (n = 5) or lung transplantation (n = 4), or left ventricular assist device (n = 2). The Cox multivariable model retained the following independent predictors of in-hospital mortality: in-ICU SRD diagnosis, day-0 Simplified Acute Physiology Score (SAPS) II score ≥ 70 and arterial lactate ≥ 7.5 mmol/L for VA-ECMO-treated patients; diagnosis other than vasculitis, day-0 SAPS II score ≥ 70, ventilator-associated pneumonia and arterial lactate ≥ 7.5 mmol/L for VV-ECMO-treated patients.

CONCLUSIONS

ECMO support is a relevant rescue technique for critically ill SRD patients, with 49% survival at hospital discharge. Vasculitis was independently associated with favorable outcomes of VV-ECMO-treated patients. Further studies are needed to specify the role of ECMO for SRD patients.

Venoarterial extracorporeal membrane oxygenation induces early immune alterations

Background

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides heart mechanical support in critically ill patients with cardiogenic shock. Despite important progresses in the management of patients under VA-ECMO, acquired infections remain extremely frequent and increase mortality rate. Since immune dysfunctions have been described in both critically ill patients and after surgery with cardiopulmonary bypass, VA-ECMO initiation may be responsible for immune alterations that may expose patients to nosocomial infections (NI). Therefore, in this prospective study, we aimed to study immune alterations induced within the first days by VA-ECMO initiation.

Methods

We studied immune alterations induced by VA-ECMO initiation using cytometry analysis to characterize immune cell changes and enzyme-linked immunosorbent assay (ELISA) to explore plasma cytokine levels. To analyze specific changes induced by VA-ECMO initiation, nine patients under VA-ECMO (VA-ECMO patients) were compared to nine patients with cardiogenic shock (control patients).

Results

Baseline immune parameters were similar between the two groups. VA-ECMO was associated with a significant increase in circulating immature neutrophils with a significant decrease in C5a receptor expression. Furthermore, we found that VA-ECMO initiation was followed by lymphocyte dysfunction along with myeloid-derived suppressor cells (MDSC) expansion. ELISA analysis revealed that VA-ECMO initiation was followed by an increase in pro-inflammatory cytokines such as IL-6, IL-8 and TNF-α along with IL-10, a highly immunosuppressive cytokine.

Conclusion

VA-ECMO is associated with early immune changes that may be responsible for innate and adaptive immune alterations that could confer an increased risk of infection.

Diagnostic Accuracy of Infection Markers to Diagnose Infections in Neonates and Children Receiving Extracorporeal Membrane Oxygenation

BACKGROUND

Infections represent one of the most common complications in patients managed on Extracorporeal Membrane Oxygenation (ECMO) and are associated with poorer outcomes. Clinical signs of infection in patients on ECMO are non-specific. We assessed the diagnostic accuracy of Procalcitonin (PCT), C-reactive protein (CRP) and White cell count (WCC) to diagnose infection on ECMO.

METHODS

Retrospective single center observational study including neonates and children <18 years treated with ECMO in 2015 and 2016. Daily data on PCT, CRP and WCC were assessed in relation to microbiologically confirmed, and clinically suspected infection on ECMO using operating characteristics (ROC) curves.

RESULTS

Sixty-five ECMO runs in 58 patients were assessed. CRP had the best accuracy with an area under the ROC curve (AUC) of 0.79 (95%-CI 0.66-0.92) to diagnose confirmed infection and an AUC of 0.72 (0.61-0.84) to diagnose confirmed and suspected infection. Abnormal WCC performed slightly worse with an AUC of 0.70 (0.59-0.81) for confirmed and AUC of 0.66 (0.57-0.75) for confirmed and suspected infections. PCT was non-discriminatory.

CONCLUSION

The diagnosis of infections acquired during ECMO remains challenging. Larger prospective studies are needed that also include novel infection markers to improve recognition of infection in patients on ECMO.

Neutrophil injury and function alterations induced by high mechanical shear stress with short exposure time

High mechanical shear stresses (HMSS) can cause damage to blood, which manifests as morphologic changes, shortened life span, biochemical alterations, and complete rupture of blood cells and proteins, leading to the alterations of normal blood function. The aim of this study is to determine the state of neutrophil activation and function alterations caused by HMSS with short exposure time relevant to ventricular assist devices. Blood from healthy donors was exposed to three levels of HMSS (75Pa, 125Pa, and 175Pa) for a short exposure time (0.5 s) using our Couette-type blood-shearing device. Neutrophil activation (Mac-1, platelet-neutrophil aggregates) and surface expression levels of two key functional receptors (CD62L and CD162) on neutrophils were evaluated by flow cytometry. Neutrophil phagocytosis and transmigration were also examined with functional assays. Results showed that the expression of Mac-1 on neutrophils and platelet-neutrophil aggregates increased significantly while the level of CD62L expression on neutrophils decreased significantly after the exposure to HMSS. The Mac-1 expression progressively increased while the CD62L expression progressively decreased with the increased level of HMSS. The level of CD162 expression on neutrophils slightly increased after the exposure to HMSS, but the increase was not significant. The phagocytosis assay data revealed that the ability of neutrophils to phagocytose latex beads coated with fluorescently labeled rabbit IgG increased significantly with the increased level of HMSS. The transmigration ability of neutrophils slightly increased after the exposure to HMSS, but did not reach a significant level. In summary, HMSS with a short exposure time of 0.5 seconds could induce neutrophil activation, platelet-neutrophil aggregation, shedding of CD62L receptor, and increased phagocytic ability. However, the exposure to the three levels of HMSS did not cause a significant change in neutrophil transmigration capacity and shedding of CD162 receptor on neutrophils.