Sepsis and ECMO

Protective effects of Dioscin against sepsis-induced cardiomyopathy via regulation of toll-like receptor 4/MyD88/p65 signal pathway

BACKGROUND

Dioscin has many pharmacological effects; however, its role in sepsis-induced cardiomyopathy (SIC) is unknown. Accordingly, we concentrate on elucidating the mechanism of Dioscin in SIC rat model.

METHODS

The SIC rat and H9c2 cell models were established by lipopolysaccharide (LPS) induction. The heart rate (HR), left ventricle ejection fraction (LVEF), mean arterial blood pressure (MAP), and heart weight index (HWI) of rats were evaluated. The myocardial tissue was observed by hematoxylin and eosin staining. 4-Hydroxy-2-nonenal (4-HNE) level in myocardial tissue was detected by immunohistochemistry. Superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) activities in serum samples of rats and H9c2 cells were determined by colorimetric assay. Bax, B-cell lymphoma-2 (Bcl-2), toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), phosphorylated-p65 (p-p65), and p65 levels in myocardial tissues of rats and treated H9c2 cells were measured by quantitative real-time PCR and Western blot. Viability and reactive oxygen species (ROS) accumulation of treated H9c2 cells were assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and dihydroethidium staining assays.

RESULTS

Dioscin decreased HR and HWI, increased LVEF and MAP, alleviated the myocardial tissue damage, and reduced 4-HNE level in SIC rats. Dioscin reversed LPS-induced reduction on SOD, CAT, GSH, and Bcl-2 levels, and increment on Bax and TLR4 levels in rats and H9c2 cells. Overexpressed TLR4 attenuated the effects of Dioscin on promoting viability, as well as dwindling TLR4, ROS and MyD88 levels, and p-p65/p65 value in LPS-induced H9c2 cells.

CONCLUSION

Protective effects of Dioscin against LPS-induced SIC are achieved via regulation of TLR4/MyD88/p65 signal pathway.

Analysis of Vancomycin Dosage and Plasma Levels in Critically Ill Adult Patients Requiring Extracorporeal Membrane Oxygenation (ECMO)

Introduction: Critically ill patients undergoing extracorporeal membrane oxygenation (ECMO) exhibit unique pharmacokinetics. This study aimed to assess the achievement of vancomycin therapeutic targets in these patients. Methods: This retrospective cohort study included patients on ECMO treated with vancomycin between January 2010 and December 2018. Ninety patients were analyzed based on ECMO connection modality, baseline creatinine levels, estimated glomerular filtration rate (eGFR), renal replacement therapy (RRT) requirements, and vancomycin loading dose administration. Results: Twenty-three percent of the patients achieved the therapeutic range defined by baseline levels. No significant differences in meeting the therapeutic goal were found in multivariate analysis considering ECMO cannulation modality, initial creatinine level, initial eGFR, RRT requirement, or loading dose use. All trough levels between 15 and 20 mcg/mL achieved an estimated area under the curve/minimum inhibitory concentration (AUC/MIC) between 400 and 600, almost all trough levels over 10 mcg/mL predicted an AUC/MIC >400. Discussion: Achieving therapeutic plasma levels in these patients remains challenging, potentially due to factors such as individual pharmacokinetics and pathophysiology. A trough plasma level between 12 and 20 estimated the therapeutic AUC/MIC for all models, proposing a possible lower target, maintaining exposure, and potentially avoiding adverse effects. Despite being one of the largest cohorts of vancomycin use in ECMO patients studied, its retrospective nature and single-center focus limits its broad applicability.

Epidemiology and outcomes of infections during extracorporeal membrane oxygenation in adult patients with COVID-19 ARDS- A single center study

BACKGROUND

There is a scarcity of data regarding nosocomial infections in patients with COVID-19 treated with ECMO. This observational study from India aims to describe the epidemiology and microbiology of infections in patients with COVID-19 associated ECMO.

METHODS

This is an ambi-directional observational study of COVID-19 ECMO patients admitted from April 2021 to June 2022 in a tertiary care hospital. The total number of sepsis episodes for each patient was recorded and were categorized as bloodstream infections (BSI), pneumonias, skin and soft tissue infections (SSTI), invasive candidiasis (IC), catheter associated urinary tract infection (CAUTI), intra-abdominal infections (IAI), and Clostridioides difficile infections. Details regarding each infection including the microbiological profile and outcomes were recorded.

RESULTS

29 patients who received ECMO for COVID-19 pneumonia during the study period were identified. Of the 29 patients, there were a total of 185 septic episodes. The incidence of septic episodes was 72.4 per 1000 ECMO days. Of the 185 sepsis events, 82 (44.3%) were BSI, 72 (39%) were pneumonia, 19 (10.3%) were SSTI, 7 (3.8%) were CAUTI and 5 (2.7%) were IAIs. Of these 29 patients, 16 (55.2%) patients were discharged and 13 (44.8%) died.

CONCLUSIONS

The most common infections in our patients were bloodstream infections followed by pneumonia. High rates of gram negative infections, including those caused by carbapenem resistant bacteria, reflect the Indian critical care unit epidemiology in general. Despite these high infection rates with antimicrobial resistant set of micro-organisms, we had a successful outcome in 55.2% of patients.

Venoarterial Extracorporeal Membrane Oxygenation Implementation in Septic Shock Rat Model

Septic shock, a global health concern, boasts high mortality rates. Research exploring the efficacy of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in septic shock remains limited. Our study aimed to establish a rodent model employing VA-ECMO in septic shock rats, assessing the therapeutic impact of VA-ECMO on septic shock. Nineteen Sprague-Dawley rats were randomly assigned to sham, septic shock, and (septic shock + VA-ECMO; SSE) groups. Septic shock was induced by intravenous lipopolysaccharides, confirmed by a mean arterial pressure drop to 25-30% of baseline. Rats in the SSE group received 2 hours of VA-ECMO support and 60 minutes of post-weaning ventilation. Sham and septic shock groups underwent mechanical ventilation for equivalent durations. Invasive mean arterial pressure monitoring, echocardiographic examinations, and blood gas analysis revealed the efficacy of VA-ECMO in restoring circulation and ensuring adequate tissue oxygenation in septic shock rats. Post-experiment pathology exhibited the potential of VA-ECMO in mitigating major organ injury. In summary, our study successfully established a stable septic shock rat model with the implementation of VA-ECMO, offering a valuable platform to explore molecular mechanisms underlying VA-ECMO's impact on septic shock.

A nomogram to predict nosocomial infection in patients on venoarterial extracorporeal membrane oxygenation after cardiac surgery

INTRODUCTION

After cardiac surgery, patients on venoarterial extracorporeal membrane oxygenation (VA-ECMO) have a higher risk of nosocomial infection in the intensive care unit (ICU). We aimed to establish an intuitive nomogram to predict the probability of nosocomial infection in patients on VA-ECMO after cardiac surgery.

METHODS

We included patients on VA-ECMO after cardiac surgery between January 2011 and December 2020 at a single center. We developed a nomogram based on independent predictors identified using univariate and multivariate logistic regression analyses. We selected the optimal model and assessed its performance through internal validation and decision-curve analyses.

RESULTS

Overall, 503 patients were included; 363 and 140 patients were randomly divided into development and validation sets, respectively. Independent predictors derived from the development set to predict nosocomial infection included older age, white blood cell (WBC) count abnormality, ECMO environment in the ICU, and mechanical ventilation (MV) duration, which were entered into the model to create the nomogram. The model showed good discrimination, with areas under the curve (95% confidence interval) of 0.743 (0.692-0.794) in the development set and 0.732 (0.643-0.820) in the validation set. The optimal cutoff probability of the model was 0.457 in the development set (sensitivity, 0.683; specificity, 0.719). The model showed qualified calibration in both the development and validation sets (Hosmer-Lemeshow test, p > .05). The threshold probabilities ranged from 0.20 to 0.70.

CONCLUSIONS

For adult patients receiving VA-ECMO treatment after cardiac surgery, a nomogram-monitoring tool could be used in clinical practice to identify patients with high-risk nosocomial infections and provide an early warning.

Extracorporeal Life Support for Patients With Newly Diagnosed HIV and Acute Respiratory Distress Syndrome: A Systematic Review and Analysis of Individual Patient Data

Extracorporeal membrane oxygenation (ECMO) may improve survival in patients with severe acute respiratory distress syndrome (ARDS). However, presence of immunosuppression is a relative contraindication for ECMO, which is withheld in HIV patients. We performed a systematic review to investigate the outcome of newly diagnosed HIV patients with ARDS receiving ECMO support. Our search yielded 288 publications, with 22 studies finally included. Initial presentation included fever, respiratory distress, and cough. Severe immunodeficiency was confirmed in most patients. Deceased patients had a higher viral load, a lower Horovitz index, and antiretroviral therapy utilized before ECMO. Moreover, ECMO duration was longer ( p = 0.0134), and all deceased suffered from sepsis ( p = 0.0191). Finally, despite the development of therapeutic options for HIV patients, ECMO remains a relative contraindication. We found that ECMO may successfully bridge the time for pulmonary recovery in 93% of patients, with a very good outcome. Using ECMO, the time for antimicrobial therapy, lung-protective ventilation, and immune system restitution may be gained. Further studies clarifying the role of ECMO in HIV are crucial and until these data are available, ECMO might be appropriate in immunocompromised patients. This holds especially true in newly diagnosed HIV patients, who are usually young, without comorbidities, with a good rehabilitation potential.

Adverse Outcomes Associated With Atrial Arrhythmias After Veno-Venous Extracorporeal Membrane Oxygenation

Veno-venous extracorporeal membrane oxygenation (VV ECMO) is used as a treatment modality in those who fail to respond to conventional care. Hypoxia and medications used in the intensive care unit may increase risk for atrial arrhythmias (AA). This study aims to evaluate the impact of AA on post-VV ECMO outcome. A retrospective review of patients who were placed on VV ECMO between October 2016 and October 2021. One hundred forty-five patients were divided into two groups, AA and no AA. Baseline characteristic and potential risk factors were assessed. Uni- and multivariate analysis using logistic regression models were constructed to evaluate the predictors of mortality between groups. Survival between groups was estimated by the Kaplan-Meier method using the log-rank test. Advanced age with history of coronary artery disease and hypertension were associated with increased risk to develop AA post-VV ECMO placement ( p value < 0.05). Length on ECMO, time intubated, hospital length of stay, and sepsis were significantly increased in patients in the AA group ( p value < 0.05). There was no difference in the overall mortality between the two groups. AAs were associated with worse hospital course and complications but no difference in overall mortality rate. Age and cardiovascular disease seem to be predisposing risk factors for this. Further studies are needed to investigate potential strategies to prevent AAs development in this population.

Sepsis in postcardiotomy cardiogenic shock patients supported with veno- arterial extracorporeal membrane oxygenation

BACKGROUND

Sepsis could affect the outcomes of patients with postcardiotomy cardiogenic shock supported with extracorporeal membrane oxygenation (ECMO). Our objectives were to characterize sepsis patients with ECMO support for postcardiotomy cardiogenic shock and assess its predictors and effect on patients' outcomes.

METHODS

This retrospective study included 103 patients with ECMO for postcardiotomy cardiogenic shock from 2009 to 2020. Patients were divided according to the occurrence and timing of sepsis into three groups. Group 1 included patients with no sepsis (n = 67), Group 2 included patients with ECMO-related sepsis (n = 10), and Group 3 included patients with non-ECMO-related sepsis (n = 26).

RESULTS

Lactate level before ECMO was highest in the ECMO-associated sepsis group (Group 1 and 2 p = 0.003 and Group 2 and 3 p = 0.003). Dialysis and gastrointestinal bleeding were highest in ECMO-associated sepsis (p = 0.03 and 0.04, respectively). Blood transfusion was higher in ECMO-associated sepsis than in patients with no sepsis (p = 0.01). Mortality was nonsignificantly higher in patients with ECMO-associated sepsis. High BMI (OR: 1.11; p = 0.004), preoperative dialysis (OR: 7.35; p = 0.02), preoperative IABP (OR: 9.9.61; p = 0.01) and CABG (OR: 6.29; p = 0.01) were significantly associated with sepsis. Older age (OR: 1.08; p = 0.004), lower BSA (OR: 0.004; p = 0.003), peripheral cannulation (OR: 29.82; p = 0.03), and high pre ECMO lactate level (OR: 1.24; p = 0.001) were associated with increased mortality. Sepsis did not predict mortality (OR: 1.83; p = 0.21).

CONCLUSIONS

Sepsis is a dreaded complication in patients with postcardiotomy cardiogenic shock, especially ECMO-associated sepsis. Preoperative risk factors could predict postoperative sepsis in ECMO patients.

Impact of surface coating and systemic anticoagulants on hemostasis and inflammation in a human whole blood model

BACKGROUND

Surface compatibility with blood is critical both for scientific investigations on hemostasis and clinical applications. Regarding in vitro and ex vivo investigations, minimal alteration in physiological hemostasis is of particular importance to draw reliable conclusions on the human coagulation system. At the same time, artificial coagulation activation must be avoided, which is relevant for the patient, for example to prevent stent graft occlusion. The aim was to evaluate the advantages and disadvantages of antithrombotic and antifouling surface coatings in the context of their suitability for ex vivo incubation and the study of coagulation properties.

METHODS

We investigated the impact of different protocols for surface coating of synthetic material and different anticoagulants on hemostasis and platelet activation in ex vivo human whole blood. Blood samples from healthy donors were incubated in coated microtubes on a rotating wheel at 37°C. Two protocols for surface coating were analyzed for hemostatic parameters and metabolic status, a heparin-based coating (CHC, Corline Heparin Conjugate) without further anticoagulation and a passivating coating (MPC, 2-methacryloyloxethyl phosphorylcholine) with added anticoagulants (enoxaparin, ENOX; or fondaparinux, FPX). Employing the MPC-based coating, the anticoagulants enoxaparin and fondaparinux were compared regarding their differential effects on plasmatic coagulation by thrombelastometry and on platelet activation by flowcytometry and platelet function assays.

RESULTS

Using the CHC coating, significant coagulation cascade activation was observed, whereas parameters remained mostly unchanged with MPC-based protocols. Extended incubation caused significantly elevated levels of the soluble membrane attack complex. Neither ENOX nor FPX caused a relevant impairment of platelet function or activation capacity and thrombelastometric parameters remained unchanged with both protocols. For translational purposes, we additionally modeled endotoxemia with the MPC-based protocols by incubating with lipopolysaccharide plus/minus thrombin. While coagulation parameters remained unchanged, elevated Interleukin 8 and Matrix Metalloproteinase 9 demonstrated preserved immune cell responsiveness.

CONCLUSIONS

The MPC-based protocols demonstrated better hemocompatibility compared to CHC, and ENOX and FPX proved useful for additional anticoagulation. Furthermore, this simple-to-use whole blood model may be useful for experimental analyses of the early coagulatory and immunological response without decalcification.

Sepsis Associated with Extracorporeal Membrane Oxygenation

Sepsis in patients on extracorporeal membrane oxygenation (ECMO) remains a serious complication. Its presence is a poor prognostic marker and increases overall mortality. Adult patients with prolonged duration on ECMO are at high risk of developing sepsis. Ventilator-associated pneumonia and bloodstream infections are the main sources of infection these patients. A strong early suspicion, drawing adequate volume for blood cultures, and early and timely administration of empirical antibiotics can help control the infection and decrease the morbidity and mortality. The diagnostic and the treatment are both challenging. Cardiac patients have increased risk of nosocomial infection while on ECMO, which may be in part due to longer cannulation times, as well as increased likelihood of undergoing major procedures or having an open chest.

Infections Acquired During Venoarterial Extracorporeal Membrane Oxygenation Postcardiac Surgery in Children: A Retrospective Observational Study

Introduction Extracorporeal membrane oxygenation (ECMO) is increasingly being used in refractory cardiac and pulmonary dysfunction as a rescue modality. The common indications for establishing venoarterial ECMO (VA-ECMO) support in children postcardiac surgery are failure to wean from cardiopulmonary bypass (CPB), postcardiotomy cardiogenic shock (PCCS), refractory pulmonary arterial hypertension, and as a bridge to recovery or transplant. The survival rate of children on VA-ECMO support is 45%. The most frequently encountered complications during VA-ECMO are bleeding, thrombosis, acute kidney injury, and infections. Among those, infections acquired during VA-ECMO lead to high morbidity and mortality. Hence, this study aimed to determine infection rates, causal microorganisms, and mortality risk factors in children developing an infection during VA-ECMO therapy.

Methods This retrospective observational study was conducted on 106 children under 14 years of age who underwent elective or emergent cardiac surgery (between 2016 and 2020) and required VA-ECMO support. Medical records were reviewed to collect the targeted variables and analyzed.

Results Out of 106 children, 49 (46.23%) acquired infections representing a prevalence of 46.23% and an infection rate of 186.4 episodes per 1,000 ECMO days. Prevalence and acquired infection rate/1,000 ECMO days were higher in the nonsurvivor group than in the survivor group (26.42 vs.19.81%) and (215.07 vs. 157.49), respectively. The bloodstream infection (BSI) and catheter-associated urinary tract infection (CAUTI) episodes were 53.04 and 68.19 per 1,000 ECMO days, and the ventilator-associated pneumonia (VAP) rate was 44.50 per 1,000 ventilator days. The mean preoperative admission duration, aortic cross-clamping duration, CPB duration (minutes), and vasoactive-inotropic score were higher in the nonsurviving children (p < 0.001). Similarly, prolonged mean ECMO duration was also found in the nonsurvivor group compared with the survivor group (p = 0.03).

Conclusion In our study, the prevalence of acquired infection during VA-ECMO was 46.23%. The incidence of BSI, CAUTI, and VAP per 1,000 ECMO days was higher in the nonsurvivor group than in survivors. Acinetobacter baumannii was the most common cultured gram-negative organism in VAP and BSI, with 67.65% Acinetobacter spp. resistant to carbapenems. CAUTI was predominately due to Candida species during VA-ECMO.

Antibiotics and ECMO in the Adult Population—Persistent Challenges and Practical Guides

Extracorporeal membrane oxygenation (ECMO) is an emerging treatment modality associated with a high frequency of antibiotic use. However, several covariables emerge during ECMO implementation, potentially jeopardizing the success of antimicrobial therapy. These variables include but are not limited to: the increased volume of distribution, altered clearance, and adsorption into circuit components, in addition to complex interactions of antibiotics in critical care illness. Furthermore, ECMO complicates the assessment of antibiotic effectiveness as fever, or other signs may not be easily detected, the immunogenicity of the circuit affects procalcitonin levels and other inflammatory markers while disrupting the immune system. We provided a review of pharmacokinetics and pharmacodynamics during ECMO, emphasizing practical application and review of patient-, illness-, and ECMO hardware-related factors.

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.