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

Prevalence and impact of ECMO cannula colonization: a single center study

During ECMO therapy, infections are common and have substantial impact on treatment outcomes. However, data on the prevalence and clinical impact of microbial ECMO cannula colonization are scarce. Between October 2020 and May 2022, we evaluated 112 ECMO cannulas from 58 patients for microbial colonization using sonication fluid culture & 16S-rRNA-PCR (n = 105), or roll plate method (n = 7). 38 (33.9%) cannulas from 30 (51.7%) patients showed evidence for bacterial colonization with the predominance of coagulase-negative staphylococci (67.4%). Antipseudomonal β-Lactam treatment at cannulation and ECMO initiation at referring hospitals were associated with cannula colonization upon multivariable per-patient analysis. The prevalence of bloodstream infections was equally low and the occurrence of fever after and number of anti-infective drugs given during ECMO therapy was similar in patients with and without exposure to colonized cannulas. Finally, there was no association of cannula colonization with adverse outcomes. In summary, our data suggest that bacterial ECMO cannula colonization does not affect the clinical course of patients and thus discourage routine microbial assessment of cannula tips or even cannula exchange in the absence of clinical signs of cannula infection.

Diagnosis of coagulase-negative Staphylococcus bacteremia in patients receiving extracorporeal membrane oxygenation

BACKGROUND

Coagulase-negative Staphylococci (CoNS) are frequently cited as the most common cause of bacteremia in patients receiving extracorporeal membrane oxygenation (ECMO), yet there is significant variability in reporting rates between centers.

METHODS

All patients who received ECMO with CoNS isolated from blood cultures between January 2022 and March 2024 were included in this retrospective cohort study. Previously reported bacteremia definitions were applied to determine the variability in rates by definition.

RESULTS

In 68 patients who received ECMO during the study period, 424 blood culture sets were obtained, of which 20 (4%) yielded CoNS in 13 (19%) patients. Only 5 (38%) patients had repeat isolation. Clinical variables, such as fever and leukocytosis, did not predict repeat positivity. Rates of CoNS varied from 0 to 15 infections per 1,000 ECMO days depending on the definition utilized.

CONCLUSIONS

CoNS were frequently isolated in blood cultures from patients receiving ECMO. Despite the concern for biofilm formation, most CoNS were only isolated in a single culture. With the limited utility of clinical markers and frequent false positives, clinicians should order repeat blood cultures on those with CoNS isolated from blood cultures. We propose a standardized definition for CoNS bacteremia, which entails isolations of CoNS from 2 subsequent blood cultures.

Daily Surveillance Blood Cultures in Children Supported With Extracorporeal Membrane Oxygenation: Single-Center, Retrospective Cohort Study, 2021-2023

OBJECTIVE

Diagnosing bloodstream infections (BSIs) in patients on extracorporeal membrane oxygenation (ECMO) can be challenging due to circuit-controlled temperature, altered hemodynamics, and questionable reliability of inflammatory markers in critically ill patients. As a result, practice variability exists among ECMO centers regarding routine blood cultures for surveillance of BSI. Our study aimed to evaluate daily surveillance blood cultures in pediatric and neonatal ECMO patients.

DESIGN

Retrospective review of daily surveillance blood cultures from January 2021 to July 2023. We evaluated signs, symptoms, and laboratory results in patients with positive blood cultures.

SETTING

Academic children's hospital, New York, NY.

PATIENTS

All pediatric and neonatal patients supported on ECMO.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We identified a cohort of 111 patients (39 neonates and 72 children) who were supported with ECMO. Daily blood cultures were obtained on 1059 (99%) of 1065 completed ECMO days. Overall, 3% (35/1059) of blood cultures were positive, affecting 6% (7/111) of patients. All seven patients had new evidence of infection on the day of their first positive blood culture; six had clinical signs of infection, including new-onset hypotension, hypothermia, or respiratory decline, and the remaining patients had newly elevated inflammatory markers.

CONCLUSIONS

Daily surveillance blood cultures are low-yield in our practice with pediatric and neonatal ECMO patients. Our experience shows that changes in clinical status, including abnormal physical or laboratory findings consistent with infection, are associated with BSI, allowing for timely diagnosis. These criteria should prompt as-needed blood cultures, reducing blood draws and preventing costly and unnecessary daily surveillance cultures.

Rising Above the Limits of Critical Care ECMO: A Narrative Review

Extracorporeal membrane oxygenation (ECMO), an advanced life support method, was developed to treat severe cardiac and pulmonary failure in critically ill patients. ECMO was previously used to treat ARDS, cardiogenic shock, and after heart or lung transplant. It has since become a versatile therapeutic and surgical tool. When conventional methods fail, this technique works well for high-risk procedures such as tracheal resections, ventricular tachycardia ablations, and complicated percutaneous coronary interventions. These uses demonstrate ECMO's ability to oxygenate and stabilize the hemodynamics in challenging clinical circumstances. Clinical studies report survival rates exceeding 60% in ECMO-assisted thoracic surgeries, underscoring its efficacy in these settings. Recent advancements, such as portable ECMO systems and artificial intelligence-driven management tools, have further enhanced the safety and effectiveness of ECMO, enabling its use in diverse clinical environments. However, challenges remain, particularly in patient selection, resource allocation, and addressing ethical dilemmas. The integration of standardized protocols and technological innovations has mitigated complications such as vascular injury and infection, contributing to improved patient outcomes. This review examines ECMO applications and integration into multidisciplinary care, its configurations, and its growing role outside the intensive care unit in elective thoracic and cardiac surgery, trauma, and non-cardiac high-risk procedures.

Pharmacokinetic Changes and Influencing Factors of Polymyxin B in Different ECMO Modes

PURPOSE

With the development of extracorporeal membrane oxygenation (ECMO) technology, the duration of ECMO support has gradually increased, leading to an increased risk of ECMO-related bacterial resistance. Polymyxin B (PMB) is used to treat drug-resistant bacterial infections. However, the pharmacokinetic (PK) parameters of antibiotics may change during ECMO, resulting in over- or under-exposure. This study aimed to clarify the changes in PK parameters and identify factors influencing PMB levels in patients receiving venovenous or venoarterial ECMO.

PATIENTS AND METHODS

A prospective PK study was performed in 11 patients receiving ECMO with resistant bacteria. After reaching a steady state, the drug concentrations of PMB pre- and post-oxygenator were measured. Nonlinear mixed-effects modelling was used to construct a population PK model for PMB. Microbial results were assessed using repeated cultures at the end of treatment. Semiquantitative microbial culture results were used to form clearance and uncleared groups.

RESULTS

The PMB concentrations were not significantly different between pre- and post-oxygenator. A two-compartment model best described the PK of PMB. ECMO flow rate was included as a covariate of clearance (CL). Continuous renal replacement therapy (CRRT) were included as covariates on the volume of the central compartment. The PK parameters central compartment, volume of the peripheral compartment, CL, and inter-compartmental clearance or flow rate(Q) were 20.41 L, 9.86 L, 3.75 L/h, and 3.82 L/h. 7 patients (63.64%) had two consecutive negative bacterial cultures at discharge. The Css,avg shows a significant difference between clearance group (2.26±0.72) and uncleared group (1.25±0.24), P<0.05.

CONCLUSION

There were no significant differences in PMB concentrations between pre- and post-oxygenator. The PK of PMB may be altered in patients receiving CRRT-ECMO. The ECMO flow rate is strongly correlated with the CL. The Css,avg is correlated with the bacterial clearance rate. In clinical practice, increasing the incidence of therapeutic drug monitoring may improve the clinical outcomes.

Clinical Practice With Preprimed Extracorporeal Membrane Oxygenation: Safety, Sterility, and Functionality

This 5 year retrospective study presents the clinical experience with preprimed extracorporeal membrane oxygenation (ECMO) circuits used in a Single Hub Center Hospital, focusing on sterility, functionality, and safety. The ECMO program has been active since 2019, with a total of 223 circuits managed. Our preassembled and preprimed ECMO circuits were stored in a sterile environment and continuously circulated until implantation. Sterility and functionality testing was performed at the end of circuit preparation, every 7 days, and before implantation. Our results show that only 2 (0.3%) of the 570 samples tested positive for bacteria, and all implanted devices demonstrated satisfactory gas transfer performance. None of the ECMO devices demonstrated any loss of early functionality after implantation. The longest storage period of a preprimed circuit was 73 days, with no positive culture results. Our study highlights the importance of preassembled and preprimed ECMO circuits in improving clinical practice in emergency situations, highlighting their safety and potential to improve clinical practice. Furthermore, our findings suggest that standardizing guidelines for prepriming and storage of ECMO circuits can help minimize the risk of contamination.

Pre-assembled ECMO: Enhancing efficiency and reducing stress in refractory cardiac arrest care

Aim

Extracorporeal cardiopulmonary resuscitation (ECPR) by veno-arterial extracorporeal membrane oxygenation (VA-ECMO) during refractory cardiac arrest presents significant medical and psychological challenges for healthcare providers. Beyond managing cardiac arrest and preparing for potential coronary angiography, the ECMO circuit must be assembled and primed under strictly sterile conditions, contributing to additional psychological stress and potential delays in ECMO cannulation. This pragmatic study thought to evaluate whether pre-assembled and pre-primed ECMO circuits (pre-primed group) maintain sterility over a 21-day period, expedite ECMO initiation in ECPR patients and alleviate the psychological burden on the ECPR team, compared to newly assembled and primed ECMO circuits (on-demand group).

Methods

In a prospective manner, ECMO circuits were either pre-assembled and pre-primed under sterile conditions, maintained for 21 days with culture samples taken every seventh day, or newly assembled and primed during the acute emergency situation. The transition from on-demand assembly and priming of ECMO circuits to pre-primed ECMO circuits occurred on January 1st, 2021. The interval between patients' arrival in the cardiac catheterization laboratory and the initiation of ECMO was recorded and retrospectively compared between the two treatment groups. The ECPR team, comprising experienced cardiologists and nurses, was prospectively surveyed using the modified Perceived Stress Questionnaire (PSQ-20).

Results

All aseptically pre-assembled and pre-primed ECMO circuits demonstrated sterile cultures for aerobic and anaerobic microorganisms as well as fungal agents over the 21-day period: 0/120 positive cultures (0 %, 95 % CI for binomial probability 0-0.03). The time to ECMO initiation was significantly reduced in the pre-primed group compared to the on-demand group: 13 [IQR 9-17] versus 31 [IQR 27-44] minutes, P < 0.001. Responses from ECPR physicians and nurses on the PSQ-20 were similar across all items. With the use of pre-primed ECMO circuits, all ECPR professionals reported a greater sense of settled inner feeling, considerably less psychological tension, fewer worries and insecurities, as well as more effective ICU shifts with improved personal goal achievement. However, treating ECPR patients with pre-primed ECMO circuits did not lead to increased job satisfaction or higher physical energy levels.

Conclusion

Aseptically pre-assembled and pre-primed ECMO circuits maintain sterility for multiple weeks, significantly reducing ECMO initiation times and alleviating psychological strain on the ECPR team. Consequently, implementing these circuits in ECPR centers could enhance both patient outcomes and healthcare provider well-being.

VENOARTERIAL EXTRACORPOREAL MEMBRANE OXYGENATION REDUCES MYOCARDIAL AND MITOCHONDRIAL DAMAGE IN ACUTE MYOCARDIAL INFARCTION

ABSTRACT

Background: Myocardial infarction (MI) is a common cardiovascular disease with a high fatality rate once accompanied by cardiogenic shock. The efficacy of extracorporeal membrane oxygenation (ECMO) in treating MI is controversial. Methods: MI was induced by ligating the left anterior descending artery (LAD) in adult male rats. Groups were defined as follows: MI group, reperfusion for 90 min after 30 min of LAD occlusion; MI + ECMO group, reperfusion and ECMO were performed for 90 min immediately after 30 min of LAD occlusion; prolonged MI + ECMO group, ECMO was used immediately after 30 min of occlusion with persistent occlusion of the LAD for an additional 30 min, followed by 90 min of reperfusion. The myocardial infarct size and mitochondrial morphology and function data were collected and compared of each group. Results: The ECMO groups had a smaller myocardial infarct size and larger percentage ejection fraction. Compared with the prolonged MI + ECMO group, the immediate reperfusion group had a lower percentage of infarct size (63.28% vs. 17.97% vs. 31.22%, MI vs. MI + ECMO vs. prolonged MI + ECMO). Mitochondria isolated from the ischemic zone showed an intact mitochondrial structure, including fewer voids and broken cristae, and preserved activity of mitochondrial complex II and complex IV in ECMO groups. Conclusions: ECMO support in MI can reduce myocardial injury despite delayed coronary reperfusion.

Incidence, risk factors and outcomes of nosocomial infection in adult patients supported by extracorporeal membrane oxygenation: a systematic review and meta-analysis

BACKGROUND

An increasing number of patients requires extracorporeal membrane oxygenation (ECMO) for life support. This supportive modality is associated with nosocomial infections (NIs). This systematic review and meta-analysis aim to assess the incidence and risk factors of NIs in adult.

METHODS

We searched PubMed, Scopus, Web of Science, and ProQuest databases up to 2022. The primary endpoint was incidence of NI. Secondary endpoints included time to infection, source of infection, ECMO duration, Intensive care and hospital length of stay (LOS), ECMO survival and overall survival. Incidence of NI was reported as pooled proportions and 95% confidence intervals (CIs), while dichotomous outcomes were presented as risk ratios (RR) as the effective index and 95% CIs using a random-effects model.

RESULTS

Among the 4,733 adult patients who received ECMO support in the 30 included studies, 1,249 ECMO-related NIs per 1000 ECMO-days was observed. The pooled incidence of NIs across 18 studies involving 3424 patients was 26% (95% CI 14-38%).Ventilator-associated pneumonia (VAP) and bloodstream infections (BSI) were the most common NI sources. Infected patients had lower ECMO survival and overall survival rates compared to non-infected patients, with risk ratio values of 0.84 (95% CI 0.74-0.96, P = 0.01) and 0.80 (95% CI 0.71-0.90, P < 0.001), respectively.

CONCLUSION

Results showed that 16% and 20% lower of ECMO survival and overall survival in patients with NI than patients without NI, respectively. However, NI increased the risk of in-hospital mortality by 37% in infected patients compared with non-infected patients. In addition, this study identified the significant positive correlation between ECMO duration and ECMO-related NI.

Severe Legionnaires' disease

BACKGROUND

Legionnaires' disease (LD) is a common but under-diagnosed cause of community-acquired pneumonia (CAP), although rapid detection of urine antigen testing (UAT) and advances in molecular testing have improved the diagnosis. LD entails intensive care unit (ICU) admission in almost one-third of cases, and the mortality rate ranges from 4% to 40%. This review aims to discuss recent advances in the study of this condition and to provide an update on the diagnosis, pathogenesis and management of severe LD.

RESULTS

The overall incidence of LD has increased worldwide in recent years due to the higher number of patients with risk factors, especially immunosuppression, and to improvements in diagnostic methods. Although LD is responsible for only around 5% of all-cause CAP, it is one of the three most common causes of CAP requiring ICU admission. Mortality in ICU patients, immunocompromised patients or patients with a nosocomial source of LD can reach 40% despite appropriate antimicrobial therapy. Regarding pathogenesis, no Legionella-specific virulence factors have been associated with severity; however, recent reports have found high pulmonary Legionella DNA loads, and impairments in immune response and lung microbiome in the most severe cases. The clinical picture includes severe lung injury requiring respiratory and/or hemodynamic support, extrapulmonary symptoms and non-specific laboratory findings. LD diagnostic methods have improved due to the broad use of UAT and the development of molecular methods allowing the detection of all Lp serogroups. Therapy is currently based on macrolides, quinolones, or a combination of the two, with prolonged treatment in severe cases.

CONCLUSIONS

Numerous factors influence the mortality rate of LD, such as ICU admission, the underlying immune status, and the nosocomial source of the infection. The host immune response (hyperinflammation and/or immunoparalysis) may also be associated with increased severity. Given that the incidence of LD is rising, studies on specific biomarkers of severity may be of great interest. Further assessments comparing different regimens and/or evaluating host-directed therapies are nowadays needed.

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).

A Comprehensive Review of Extra Corporeal Membrane Oxygenation: The Lifeline in Critical Moments

Extracorporeal membrane oxygenation (ECMO) has evolved into a pivotal intervention in critical care, offering a lifeline for patients facing severe respiratory or cardiac failure. This review provides a comprehensive exploration of ECMO, spanning its definition and historical background to its contemporary advancements and ongoing impact in critical care. The versatility of ECMO in addressing diverse critical conditions, careful patient selection criteria, and the nuanced management of complications are discussed. Advances in technology, including miniaturization, novel circuit designs, and the integration of remote monitoring, showcase the evolving landscape of ECMO. The review underscores the ongoing impact of ECMO in improving survival rates, enhancing mobility, and enabling remote expertise. As a symbol of hope and innovation, ECMO's lifesaving potential is evident in its ability to navigate the complexities of critical care and redefine the boundaries of life support interventions.