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.

Nosocomial Infections in Nonsurgical Patients Undergoing Extracorporeal Membrane Oxygenation: A Retrospective Analysis in a Chinese Hospital

Background

The effect of nosocomial infections (NIs) in adult patients undergoing ECMO has been rarely reported in China. Moreover, the effect of NIs on ECMO patients’ mortality is still unclear and inconclusive according to literature data. In this study, we examined the prevalence, risk factors, causative organisms, and effects on outcomes of NIs in ECMO patients.

Methods

A total of 79 nonsurgical patients (mean age 53.3±15.2 year (yr); 66% male) who underwent ECMO between January 2011 and September 2020 were enrolled in this retrospective study. Patients’ demographic and clinical data and ECMO parameters were collected from all patients.

Results

Among 79 patients who underwent ECMO for a total of 1253 ECMO days (mean time 15.9±14.1 d), 42 developed NIs. We observed 30 ventilator-associated pneumonia (VAP), 19 bloodstream infections (BSIs), and 4 urinary tract infections, corresponding to 23.9/1000 ECMO days, 15.2/1000 ECMO days, and 3.2/1000 ECMO days, respectively. ECMO duration (22.0±16.5 VS 8.9±5.3 d, P < 0.001), invasive mechanical ventilation (IMV) duration (27.4±20.5 VS 11.4±10.1 d, P < 0001), and ICU length of stay (35.9±22.9 VS 15.7±9.2 d, P < 0.001) were longer in patients with NIs. The independent risk factors for NIs were ECMO duration (Odds Ratio [OR], 1.414; 95% Confidence Interval [CI], (1.051–1.238); P = 0.002) and viral pneumonia (OR, 5.788; 95% CI, (1.551–21.596); P = 0.009). Gram-negative bacteria were the most common causative organisms of NIs; Acinetobacter baumannii (A. baumannii), Klebsiella pneumoniae (K. pneumoniae), and Pseudomonas aeruginosa (P. aeruginosa) were the most common bacteria. BSI (OR, 8.106; 95% CI, (1.384–47.474); P = 0.02) was an independent predictor for mortality.

Conclusion

NIs are common complications in patients during ECMO treatment, especially VAP, followed by BSI. Also, BSI can negatively affect the survival rate.

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.

Hospital-Acquired Infection in Pediatric Subjects With Congenital Heart Disease Postcardiotomy Supported on Extracorporeal Membrane Oxygenation

OBJECTIVE

To determine prevalence of and risk factors for infection in pediatric subjects with congenital heart disease status postcardiotomy supported on extracorporeal membrane oxygenation, as well as outcomes of these subjects.

DESIGN

Retrospective cohort from the Extracorporeal Life Support Organization.

SETTING

U.S. and international medical centers providing care to children with congenital heart disease status postcardiotomy.

PATIENTS

Critically ill pediatric subjects less than 8 years old admitted to medical centers between January 1, 2013, and December 31, 2015, who underwent cardiac surgery for congenital heart disease and required extracorporeal membrane oxygenation support within the first 14 postoperative days. Subjects were excluded if they underwent orthotopic heart transplantation, required preoperative extracorporeal membrane oxygenation, and had more than one postoperative extracorporeal membrane oxygenation run.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 1,314 extracorporeal membrane oxygenation subject encounters in the Extracorporeal Life Support Organization registry met inclusion criteria. Neonates comprised 53% (n = 696) of the cohort, whereas infants made up 33% (n = 435). Of the 994 subjects with Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery categorizable surgery, 33% (n = 325) were in Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 4 and 23% (n = 231) in Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 5. While on extracorporeal membrane oxygenation, 229 subjects (17%) acquired one or more extracorporeal membrane oxygenation-related infections, which represents an occurrence rate of 67 infections per 1,000 extracorporeal membrane oxygenation days. Gram-negative (62%) and Gram-positive (42%) infections occurred most commonly. Forty percent had positive blood cultures. Infants and children were at higher infection risk compared with neonatal subjects; subjects undergoing less complex surgery had higher infection rates. Unadjusted survival to hospital discharge was lower in infected subjects compared with noninfected subjects (43% vs 51%; p = 0.01). After adjusting for confounders via propensity matching, we identified no significant mortality difference between infected and noninfected subjects.

CONCLUSIONS

Neonatal and pediatric subjects in this study have a high rate of acquired infection. Infants and children were at higher infection risk compared with neonatal subjects. There was not, however, a significant association between extracorporeal membrane oxygenation-related infection and survival to hospital discharge after propensity matching.

A Systematic Review of Preexisting Sepsis and Extracorporeal Membrane Oxygenation

We retrospectively reviewed all pertinent extracorporeal membrane oxygenation (ECMO) studies (January 1995 to September 2017) of adults with sepsis as a primary indication for intervention and its association with morbidity and mortality. Collected data included study type, ECMO configuration, outcomes, effect size, and other features. Advanced age was a risk factor for death. Compared with nonsurvivors, survivors had a lower median Sepsis-Related Organ Failure Assessment score on day 3 (15 vs. 18, p = 0.01). Biomarkers in survivors and nonsurvivors, respectively, were peak lactate (from two studies: 4.5 vs. 15.1 mmol/L, p = 0.03; 3.6 ± 3.7 vs. 3.3 ± 2.4 mmol/L, p = 0.850) and procalcitonin levels (41 vs. 164 ng/ml, p = 0.008). Bacteremia was associated with catheter colonization, and 90.5% of a group without bloodstream infections survived to discharge; ECMO weaning was possible for less than half the bloodstream infection group. Myocarditis portended favorable outcomes for patients with sepsis who received ECMO. Extracorporeal membrane oxygenation was used in immunosuppressed patients with refractory cardiopulmonary insufficiency from severe sepsis with successful weaning from ECMO for most patients. Overall survival varied substantially among studies (15.38-71.43%). Existing studies do not present well-defined patterns supporting use of ECMO in sepsis because of sample sizes and disparate study designs.

Extracorporeal membrane oxygenation as a bridge to lung transplantation in a Turkish lung transplantation program: our initial experience

Lung transplantation is a life-saving treatment for patients with end-stage lung disease. Although the number of lung transplants has increased over the years, the number of available donor lungs has not increased at the same rate, leading to the death of transplant candidates on waiting lists. In this paper, we presented our initial experience with the use of extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation. Between December 2016 and August 2018, we retrospectively reviewed the use of ECMO as a bridge to lung transplantation. Thirteen patients underwent preparative ECMO for bridging to lung transplantation, and seven patients successfully underwent bridging to lung transplantation. The average age of the patients was 45.7 years (range, 19–62 years). The ECMO support period lasted 3–55 days (mean, 18.7 days; median, 13 days). In seven patients, bridging to lung transplantation was performed successfully. The mean age of patients was 49.8 years (range 42–62). Bridging time was 3–55 days (mean, 19 days; median, 13 days). Two patients died in the early postoperative period. Five patients survived until discharge from the hospital. One-year survival was achieved in four patients. ECMO can be used safely for a long time to meet the physiological needs of critically ill patients. The use of ECMO as a bridge to lung transplantation is an acceptable treatment option to reduce the number of deaths on the waiting list. Despite the successful results achieved, this approach still involves risks and complications.

Sepsis and ECMO

Sepsis is being recognized as an important complication of extracorporeal membrane oxygenation (ECMO) and its presence is a poor prognostic marker and increases the overall mortality. The survival rate differs in the various types of cannulation techniques. Adult patients with prolonged duration of ECMO constitute the major risk population. Ventilator-associated pneumonia and bloodstream infections form the main sources of sepsis in these patients. It is important to know the most common etiological agents for sepsis in ECMO, which varies partly with the local epidemiology of the hospitals. A high index of suspicion, drawing adequate volumes for blood culture and early and timely administration of appropriate empirical antimicrobials can substantially decrease the morbidity and mortality in this high-risk population. The dosing of antimicrobials is influenced by the pharmacological variations on ECMO machine and is an important consideration. Infection control practices are of paramount importance and need to be followed meticulously to prevent sepsis in ECMO.

Infection profile in neonatal patients during extracorporeal membrane oxygenation

OBJECTIVES

To describe risk factors for acquired infection during neonatal extracorporeal membrane oxygenation and to examine the predictive value of inflammatory markers in the diagnosis of infection.

METHODS

A retrospective study was conducted with data for patients under 30 days supported with extracorporeal membrane oxygenation from 2003 to April 2016, in a neonatal intensive care unit.

RESULTS

Our study included 160 neonatal patients, the average age of connection was 8.5 days and the duration of extracorporeal membrane oxygenation support was 9.7 days. The incidence of confirmed infection was 23%. Patients with confirmed infection present more frequently: vaginal delivery, lower birth weight, female sex, diagnosis of congenital diaphragmatic hernia, and longer duration of extracorporeal membrane oxygenation. When comparing the group of patients with confirmed infection and suspicion of infection, there were no significant differences in the inflammatory markers. When calculating the slope for each one, the difference in white blood cell count slope 72 h before the infection is significant; in patients with confirmed infection, the count of white blood cell increases (slope: 0.25), versus the group of patients with suspected infection in whom the count decreases (slope: -0.39). No differences were found in other variables.

CONCLUSION

Our study describes that the factors that increase the risk of infection are lower birth weight, vaginal birth, duration of extracorporeal membrane oxygenation, and a positive trend of white blood cell 72 h prior to infection/suspicion. Further studies are necessary to include or definitively rule out the use of these factors and the biomarkers as predictors of infection in neonatal patients supported with extracorporeal membrane oxygenation.

Nosocomial Infections During Extracorporeal Membrane Oxygenation in Neonatal, Pediatric, and Adult Patients: A Comprehensive Narrative Review

OBJECTIVES

Extracorporeal membrane oxygenation is increasingly used in critically ill patients with refractory cardiopulmonary failure. Nosocomial infection acquired during extracorporeal membrane oxygenation represents one of the most frequent complications but the available evidence on the risk of infection and its association with outcomes has not been comprehensively analyzed. We performed a narrative review examining the epidemiology of nosocomial infection during extracorporeal membrane oxygenation, association with clinical outcomes, and preventive strategies.

DATA SOURCES

We searched PubMed, Web of Science, EMBASE, and the Cochrane Library between 1972 and June 2018.

STUDY SELECTION

We included any article which detailed nosocomial infection during extracorporeal membrane oxygenation. Articles were excluded if they were not written in English, detailed extracorporeal membrane oxygenation use for infections acquired prior to extracorporeal membrane oxygenation, or used other forms of extracorporeal support such as ventricular assist devices.

DATA EXTRACTION

Two reviewers independently assessed eligibility and extracted data. We screened 984 abstracts and included 59 articles in the final review.

DATA SYNTHESIS

The reported risk of nosocomial infection among patients receiving extracorporeal membrane oxygenation ranged from 3.5% to 64% per extracorporeal membrane oxygenation run, while the incidence of infection ranged from 10.1 to 116.2/1,000 extracorporeal membrane oxygenation days. Nosocomial infections during extracorporeal membrane oxygenation were consistently associated with longer duration of extracorporeal membrane oxygenation and, in several large multicenter studies, with increased mortality. Risk factors for nosocomial infection included duration of extracorporeal membrane oxygenation, mechanical and hemorrhagic complications on extracorporeal membrane oxygenation, and use of venoarterial and central extracorporeal membrane oxygenation. Biomarkers had low specificity for infection in this population. Few studies examined strategies on how to prevent nosocomial infection on extracorporeal membrane oxygenation.

CONCLUSIONS

Nosocomial infections in extracorporeal membrane oxygenation patients are common and associated with worse outcomes. There is substantial variation in the rates of reported infection, and thus, it is possible that some may be preventable. The evidence for current diagnostic, preventive, and therapeutic strategies for infection during extracorporeal membrane oxygenation is limited and requires further investigation.

Outcomes of pediatric oncology and hematopoietic cell transplant patients receiving extracorporeal membrane oxygenation

BACKGROUND/OBJECTIVES

There is controversy regarding the utilization of extracorporeal membrane oxygenation in pediatric patients with an underlying oncologic diagnosis or who have undergone hematopoietic cell transplant. We hypothesized that these patients have higher mortality, more bleeding complications, more blood product utilization, and a higher rate of new infections than the general pediatric intensive care unit population supported with extracorporeal membrane oxygenation.

DESIGN/METHODS

This is a retrospective chart review at a single center quaternary care pediatric hospital including all pediatric intensive care unit extracorporeal membrane oxygenation patients from 2011 to 2016. Patients were categorized as either oncology/hematopoietic cell transplant or general pediatric intensive care unit. Patients from the cardiovascular intensive care unit or the neonatal intensive care unit were excluded.

RESULTS

A total of 38 patients met inclusion criteria of which 7 were oncology/hematopoietic cell transplant patients. The oncology/hematopoietic cell transplant group had lower platelets at the start of extracorporeal membrane oxygenation (p = 0.02) but other pre-extracorporeal membrane oxygenation characteristics were similar. Extracorporeal membrane oxygenation survival was lower in the oncology/hematopoietic cell transplant group (29% vs 77%, p = 0.02). The incidence of bleeding complications and new infections did not differ. The oncology/hematopoietic cell transplant group received more platelets (median of 15.9 mL/kg/day (interquartile range 8.4, 36.6) vs 7.9 mL/kg/day (3.3, 21.9), p = 0.04) and fresh frozen plasma (14.0 mL/kg/day (3, 15.7) vs 1.8 mL/kg/day (0.5, 5.9), p = 0.04).

CONCLUSION

Oncology and hematopoietic cell transplant patients had a higher mortality and received more blood products while on extracorporeal membrane oxygenation than the general pediatric intensive care unit patients despite similar pre-extracorporeal membrane oxygenation characteristics. Physicians should use caution when deciding whether or not to utilize extracorporeal membrane oxygenation in this population.

Bloodstream infections during post-cardiotomy extracorporeal membrane oxygenation: Incidence, risk factors, and outcomes

Introduction:

Veno-arterial extracorporeal membrane oxygenation after heart surgery is a relatively common procedure. It is easily applicable but associated with a number of complications, including bloodstream infections. The aim of this study is to determine the current rate and the risk factors related to bloodstream infections acquired during post-cardiotomy veno-arterial extracorporeal membrane oxygenation.

Methods:

Single-center retrospective study. From the overall population receiving any kind of extracorporeal membrane oxygenation from March 2013 through December 2017, the post-cardiotomy patient population was extracted, with a final sample of 92 veno-arterial extracorporeal membrane oxygenations. The risk of developing bloodstream infections as a function of extracorporeal membrane oxygenation exposure was analyzed with appropriate statistical analyses, including a Kaplan–Meier analysis.

Results:

Overall, 14 (15.2%) patients developed a bloodstream infection during extracorporeal membrane oxygenation or within the first 48 h after extracorporeal membrane oxygenation removal. The total extracorporeal membrane oxygenation duration in the population was 567 days, and the incidence of bloodstream infections was 24.7 bloodstream infections/1000 extracorporeal membrane oxygenation days. There was a progressive increase in the cumulative hazard ratio during the first 7 days, reaching a value of 20% on day 7; from day 7 and day 15, the hazard ratio remained stable, with a second increase after day 15. The independent risk factors associated with bloodstream infections were adult age, pre-implantation serum total bilirubin level, and the amount of chest drain blood loss.

Discussion:

Infections acquired during veno-arterial extracorporeal membrane oxygenation are common. Identify the risk factors that may improve strategies for treatment and prevention.

Acquired infection during neonatal and pediatric extracorporeal membrane oxygenation

INTRODUCTION

Our objectives are to (1) describe the pathogens, site, timing and risk factors for acquired infection during neonatal and pediatric ECMO and (2) explore the association between acquired infection and mortality.

METHODS

Secondary analysis of prospective data collected by the Collaborative Pediatric Critical Care Research Network between December 2012 and September 2014. Clinical factors associated with acquired infection were assessed with multivariable Cox regression. Factors associated with mortality were assessed with logistic regression.

RESULTS

Of 481 patients, 247 (51.3%) were neonates and 400 (83.2%) received venoarterial ECMO. Eighty (16.6%) patients acquired one or more infections during ECMO; 60 (12.5%) patients had bacterial, 21 (4.4%) had fungal and 11 (2.3%) had viral infections. The site of infection included respiratory for 53 (11.0%) patients, bloodstream for 21 (4.4%), urine for 20 (4.2%) and other for 7 (1.5%). Candida species were most common. Median time to infection was 5.2 days (IQR 2.3, 9.6). On multivariable analysis, a greater number of procedures for ECMO cannula placement was independently associated with increased risk of acquired infection during ECMO (Hazard Ratio 2.13 (95% CI 1.22, 3.72), p<0.01) and receiving ECMO in a neonatal ICU compared to a pediatric or cardiac ICU was associated with decreased risk (Hazard Ratio pediatric ICU 4.25 (95% CI 2.20, 8.20), cardiac ICU 2.91 (95% CI 1.48, 5.71), neonatal ICU as reference, p<0.001). Acquired infection was not independently associated with mortality.

CONCLUSION

ECMO procedures and location may contribute to acquired infection risk; however, acquired infection did not predict mortality in this study.

Infections in Children Receiving Extracorporeal Life Support

Objective.

To describe risk factors for and the outcome of infections in children receiving extracorporeal life support (ECLS) and to determine the need for removal of foreign bodies with bloodstream infections (BSIs) in children receiving ECLS.

Design.

Retrospective cohort study.

Setting.

Tertiary care children's hospital.

Patients.

Children receiving ECLS from May 1997 through May 2007.

Methods.

For patients with documented infections, medical records were examined for demographic, clinical, and laboratory details. Patients with and without documented infections were compared with regard to demographic characteristics and ECLS course.

Results.

One hundred seventeen patients underwent ECLS for a total of 878 days (median, 5.12 days). Thirty-five patients (29.9%) developed 55 infections, including 21 BSIs (38.2%), 20 urinary tract infections (36.4%), 6 ventilator-associated pneumonia episodes (10.9%), 2 viral infections (3.6%), and 6 miscellaneous infections (10.9%). The rates (in cases per 1,000 ECLS-days) were 23.9 for BSI, 22.8 for urinary tract infection, and 6.8 for ventilator-associated pneumonia. There were no significant differences in the demographic characteristics, indications for ECLS, or ECLS course between infected and uninfected patients, except for the median duration of ECLS (10.1 vs 3.8 days; P < .001). One death was attributed to infection. Resolution of BSI occurred without removal of foreign bodies in 18 (85.7%) of 21 children.

Conclusions.

Longer duration of ECLS was the only identified risk factor for infection. Mortality was not statistically significantly different between infected and uninfected patients. Most BSIs that occurred during ECLS cleared without removal of foreign bodies.

Risk factors associated with adverse outcome following extracorporeal life support: analysis from 360 consecutive patients

OBJECTIVE

Risk factors for adverse outcome after extracorporeal life support (ECLS) are yet to be defined. For this purpose, we reviewed our institutional data from more than a decade, focusing on patients with ECLS.

METHODS

Between December 2001 and June 2013, 360 consecutive cardiac surgical patients received ECLS for post-cardiotomy cardiogenic shock, with high mortality risk despite optimal conventional therapy. Patient demographics, clinical characteristics, ECLS-related morbidity, as well as in-hospital and long-term mortality were analysed. Multivariate logistic regression analysis was performed to identify independent predictors of adverse outcome (failed ECLS weaning, in-hospital mortality).

RESULTS

The mean age was 62±17 years, 76% were male and the mean preoperative ejection fraction was 35±16%. ECLS was established through peripheral (90%) or central thoracic cannulation. The mean duration of ECLS was 7±1 days. Intra-aortic balloon pumps were implanted in 22% of the patients. ECLS weaning was successful in 58% and 30% could be discharged from hospital. The main cause of death was sepsis (69%). Overall, major cerebrovascular events occurred in 12% (bleeding 3%, embolic 9%), limb ischaemia in 13%, gastrointestinal complications in 16% and renal replacement therapy in 61%. Independent risk factors for adverse outcome were prior cardiorespiratory resuscitation (OR: 4.1, 95%CI: 0.34-4.21, p=0.04), pH <7.1 (OR: 2.8, 95%CI: 0.45-3.28, p=0.01), serum lactate >120 mg/dL (OR: 2.6, 95%CI: 0.75-2.96, p< 0.01), norepinephrine dosage >0.5 µg/kg/min (OR: 2.4, 95%CI: 0.35-2.92, p=0.02) and age >75 years (OR: 2.0, 95%CI: 0.41-2.88, p=0.02). Kaplan Meier estimates for long-term survival were 26±3% at one year and 22±2% at five years.

CONCLUSION

ECLS therapy offers one-year survival to one quarter of patients with an otherwise fatal prognosis. Procedural mortality is low and morbidity at the implantation site typically moderate. Thus, prolonged metabolic deterioration in combination with high-dose vasopressor support prior to ECLS therapy should be avoided, particularly in younger patients.

Microbial adhesion on membrane oxygenators in patients requiring extracorporeal life support detected by a universal rDNA PCR test

Extracorporeal membrane oxygenation (ECMO) represents a temporary life-saving therapy for respiratory or circulatory failure, but infections during ECMO support are a life-threatening complication. Surface-related infections of ECMO are mentioned, but rarely described in the literature. A universal rDNA polymerase chain reaction (PCR) test was used to investigate the potential microbiological colonization of membrane oxygenators (MOs) in 20 patients undergoing ECMO. The overall patient-based positivity by PCR was 45%. Gram-positive bacteria (71%) represented the most abundant microorganisms on MO surfaces, followed by Gram-negative bacteria (22%) and fungi (7%). The most frequently detected causative pathogens were staphylococci (58%). Bacterial mixed infections represented 56% of all infections. In four PCR-positive cases, the pathogens detected on the MO surfaces were also found by blood culture or by culture of specimens obtained from the infectious focus. In conclusion, hollow fiber membranes of MOs can be colonized by microorganisms and appear to be a potential source of bacterial and fungal infections in ECMO patients. These infections may pose an increased risk for clinical worsening. As a consequence, persistent septic complications have to be discussed as an indication for MO exchange. The initial results suggest that the applied PCR assay is a valuable tool to investigate MOs.

Infections acquired by adults who receive extracorporeal membrane oxygenation: risk factors and outcome

OBJECTIVES

To analyze infectious complications that occur in patients who receive extracorporeal membrane oxygenation (ECMO), associated risk factors, and consequences on patient outcome.

DESIGN

Retrospective observational survey from 2005 through 2011.

PARTICIPANTS AND SETTING

Patients who required ECMO in an Australian referral center.

METHODS

Cases of bloodstream infection (BSI), catheter-associated urinary tract infection (CAUTI), and ventilator-associated pneumonia (VAP) that occurred in patients who received ECMO were analyzed.

RESULTS

A total of 146 ECMO procedures were performed for more than 48 hours in 139 patients, and 36 patients had a total of 46 infections (30.1 infectious episodes per 1,000 days of ECMO). They included 24 cases of BSI, 6 of them secondary to VAP; 23 cases of VAP; and 5 cases of CAUTI. The most frequent pathogens were Enterobacteriaceae (found in 16 of 46 cases), and Candida was the most common cause of BSI (in 9 of 24 cases). The Sequential Organ Failure Assessment score before ECMO initiation and the number of days of support were independently associated with a risk of BSI, with odds ratios of 1.23 (95% confidence interval [CI], 1.03-1.47; [Formula: see text]) and 1.08 (95% CI, 1.03-1.19]; [Formula: see text]), respectively. Infected patients did not have a significantly higher mortality compared with uninfected patients (41.7% vs 32%; [Formula: see text]), but intensive care unit length of stay (16 days [interquartile range, 8-26 days] vs 11 days [IQR, 4-19 days]; [Formula: see text]) and hospital length of stay (33.5 days [interquartile range, 15.5-55.5] vs 24 days [interquartile range, 9-42 days]; [Formula: see text]) were longer.

CONCLUSION

The probability of infection increased with the duration of support and the severity of illness before initiation of ECMO. Infections affected length of stay but did not have an impact on mortality.

Fungal infections and antifungal prophylaxis in pediatric cardiac extracorporeal life support

OBJECTIVE

Infections acquired by children during extracorporeal membrane oxygenation (ECMO) increase mortality. Our aim was to evaluate the effectiveness of prophylactic fluconazole on the incidence of fungal infections and to assess whether hospital-acquired fungal infection is associated with increased in-hospital mortality in pediatric cardiac patients requiring ECMO.

METHODS

We retrospectively reviewed a prospectively maintained database and collected data on all hospital-acquired infections in patients supported for cardiac indications at a tertiary children's hospital from 1989 to 2008.

RESULTS

ECMO was deployed 801 times in 767 patients. After exclusion criteria were applied, 261 pediatric patients supported for cardiac indications were studied. Fungal infection (blood, urine, or surgical site) occurred in 12% (31/261) of patients, 9 (7%) of 127 patients receiving fluconazole prophylaxis versus 22 (16.4%) of 134 without antifungal prophylaxis (P = .02). Using a multivariable logistic regression model, the absence of fluconazole prophylaxis was associated with an increased risk of fungal infection (odds ratio [OR] = 2.8; 95% confidence intervals [CI], 1.2, 6.7; P = .016). In a multivariable logistic regression model for in-hospital mortality, the presence of fungal infection was associated with increased odds (OR = 3.8; 95% CI, 1.5, 9.6; P = .005) of in-hospital mortality among cardiac patients requiring ECMO, and the absence of antifungal prophylaxis showed a trend toward the same (OR = 1.6; 95% CI, 0.96, 2.8; P = .072).

CONCLUSIONS

Children with cardiac disease supported with ECMO who acquire fungal infections have increased mortality. Routine fluconazole prophylaxis is associated with lower rates of fungal infections in these patients.

Infections occurring during extracorporeal membrane oxygenation use in adult patients

OBJECTIVE

The application of extracorporeal membrane oxygenation in adults has been increasing, but infections occurring during extracorporeal membrane oxygenation use are rarely described.

METHODS

We retrospectively analyzed the prospectively collected data on nosocomial infection surveillance of 334 patients aged 16 years or more undergoing their first extracorporeal membrane oxygenation for more than 48 hours at a university hospital from 1996 to 2007 for respiratory (20.4%) and cardiac (79.6%) support.

RESULTS

During a total of 2559 extracorporeal membrane oxygenation days, 55 episodes of infections occurred in 45 patients (13.5%), including 38 bloodstream (14.85 per 1000 extracorporeal membrane oxygenation days), 6 surgical site, 4 respiratory tract, 3 urinary tract, and 4 other infections. Stenotrophomonas maltophilia (16.7%) and Candida species (14.6%) were the predominant blood isolates. In stepwise logistic regression analysis, longer duration of extracorporeal membrane oxygenation use (odds ratio 1.003; 95% confidence interval, 1.001-1.005; P = .004), mechanical complications (odds ratio, 4.849; 95% confidence interval, 1.569-14.991; P = .006), autoimmune disease (odds ratio, 6.997; 95% confidence interval, 1.541-31.766; P = .012), and venovenous mode (odds ratio, 4.473; 95% confidence interval, 1.001-19.977; P = .050) were independently associated with a higher risk for infections during extracorporeal membrane oxygenation use. Overall in-hospital mortality was 68.3%, and its independent risk factors included older age (odds ratio, 1.037; 95% confidence interval, 1.021-1.054; P < .001), neurologic complications (odds ratio, 51.153; 95% confidence interval, 6.773-386.329; P < .001), and vascular complications (odds ratio, 1.922; 95% confidence interval, 1.112-3.320; P < .001), but not infections during extracorporeal membrane oxygenation use.

CONCLUSIONS

Bloodstream infection was the most common infection during extracorporeal membrane oxygenation use. Duration of extracorporeal membrane oxygenation, mechanical complications, autoimmune disease, and venovenous mode seemed to be independently associated with infections.

Potential drug sequestration during extracorporeal membrane oxygenation: results from an ex vivo experiment

OBJECTIVE

Using an ex vivo simulation model we set out to estimate the amount of drug lost due to sequestration within the extracorporeal circuit over time.

DESIGN

Simulated closed-loop extracorporeal membrane oxygenation (ECMO) circuits were prepared using a 1.5-m2 silicone membrane oxygenator. Group A consisted of heparin, dopamine, ampicillin, vancomycin, phenobarbital and fentanyl. Group B consisted of epinephrine, cefazolin, hydrocortisone, fosphenytoin and morphine. Drugs were tested in crystalloid and blood-primed circuits. After administration of a one-time dose of drugs in the priming fluid, baseline drug concentrations were obtained (P0). A simultaneous specimen was stored for stability testing at 24 h (P4). Serial post-membrane drug concentrations were then obtained at 30 min (P1), 3 h (P2) and 24 h (P3) from circuit fluid.

MEASUREMENTS AND RESULTS

One hundred and one samples were analyzed. At the end of 24 h in crystalloid-primed circuits, 71.8% of ampicillin, 96.7% of epinephrine, 17.6% of fosphenytoin, 33.3% of heparin, 17.5% of morphine and 87% of fentanyl was lost. At the end of 24 h in blood-primed extracorporeal circuits, 15.4% of ampicillin, 21% of cefazolin, 71% of voriconazole, 31.4% of fosphenytoin, 53.3% of heparin and 100% of fentanyl was lost. There was a significant decrease in overall drug concentrations from 30 min to 24 h for both crystalloid-primed circuits (p = 0.023) and blood-primed circuits (p = 0.04).

CONCLUSIONS

Our ex vivo study demonstrates serial losses of several drugs commonly used during ECMO therapy. Therapeutic concentrations of fentanyl, voriconazole, antimicrobials and heparin cannot be guaranteed in patients on ECMO.

Healthcare-associated infection in pediatric patients on extracorporeal life support: The role of multidisciplinary surveillance

OBJECTIVE

To describe the use of a multidisciplinary approach to sepsis surveillance and evaluate impact on outcome.

DESIGN

Prospective clinical study or clinical audit cycle.

SETTING

Tertiary pediatric extracorporeal membrane oxygenation (ECMO) center.

PATIENTS

Patients were 215 children supported with ECMO January 1999 to December 2004.

INTERVENTIONS

A multidisciplinary team met monthly to evaluate cases of bloodstream infection and mediastinitis, review trends, and update unit policies. Changes in practice were made at the end of 2001 in order to address a perceived high rate of sepsis: a) reeducation; b) introduction of electively preprimed ECMO circuits; and c) preference for neck rather than chest cannulation in cardiac patients. Prophylactic antibiotics were used from preprocedure for 24 hrs only throughout the study.

MEASUREMENTS AND MAIN RESULTS

Over the entire study period, 39 children had 47 septic episodes, with a rate of 24.9 per 1000 ECMO days. Multiple logistic regression analyses indicated that infection was associated with duration of ECMO support (odds ratio 1.24; 95% confidence interval 1.15, 1.35 per day) and case type: Closed vs. open chest was protective in cardiac patients (odds ratio 0.08; 95% confidence interval 0.01, 0.50). Infection increased the odds of death by 2.01 (95% confidence interval 1.00, 4.05), but this effect was less important than case type and ECMO days. After policy changes were implemented, there was a reduction in sepsis from 29.3 to 20.1 episodes per 1000 ECMO days. There was reduced sepsis in respiratory patients: neonates from 28.0 to 6.6 and pediatric patients from 42.4 to 16.9 episodes per 1000 ECMO days. Despite policy changes, sepsis remained a problem in cardiac patients with open sternum: 65.1 per 1000 ECMO days.

CONCLUSIONS

ECMO support is a high-risk setup for nosocomial infection, in particular for cardiac patients with open sternum for whom antibiotic prophylaxis is justified. Multidisciplinary surveillance offers an excellent approach for quality improvement in this challenging field.

Nosocomial catheter-related bloodstream infections in a pediatric intensive care unit: risk and rates associated with various intravascular technologies

OBJECTIVE

Nosocomial bloodstream infections are associated with increased patient morbidity, mortality, and hospital costs. More than 90% of these infections are related to the use of intravascular catheter devices. This study was done to assess the risk and rates of catheter related-bloodstream infections (CR-BSI) associated with different intravascular technologies in a pediatric intensive care unit population.

DESIGN

Retrospective cohort study.

SETTING

A 16-bed pediatric intensive care unit in a tertiary children's hospital.

STUDY POPULATION

All admissions between July 1997 and December 1999 requiring placement of an intravascular access device for care were examined. Patients with CR-BSI were identified through ongoing surveillance using Centers for Disease Control/National Nosocomial Infections Surveillance System definitions for bloodstream infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 2,728 admissions during the review period, 1,043 (38.3%) required placement of an intravascular access device. Bivariate analysis revealed that patients who required intravascular cannulae for extracorporeal life support had a 10-fold increased risk of developing a CR-BSI, and patients requiring vascular access for renal replacement therapy demonstrated a 4-fold increase in the risk of developing CR-BSI compared with the referent group. There was a significant increase in the CR-BSI rate associated with the use of more intravascular access devices per patient admission. Multivariate logistic regression identified the use of extracorporeal life support therapy and the total duration of use of intravascular access devices as significant independent predictors of CR-BSI when controlling for other predictors.

CONCLUSION

The use of extracorporeal life support therapy, the presence of multiple intravascular access devices, and the total duration of intravascular access device use were associated with an increase in the rate and risk of developing CR-BSI in our pediatric intensive care unit population. Larger, prospective studies may help elucidate additional factors responsible for these observations.

Usefulness of surveillance cultures in neonatal extracorporeal membrane oxygenation

Sepsis is difficult to identify in patients treated with extracorporeal membrane oxygenation (ECMO). This study evaluates the usefulness of surveillance cultures obtained during ECMO. We retrospectively reviewed the records of 187 patients from four ECMO centers with birth weights 1,574 to 4,900 gm and gestational ages 33-43 weeks, over a 4 year interval. Most patients had surveillance blood cultures daily, and tracheal aspirates and urine culture every other day. Charts were reviewed for culture results before, during, and for the 7 days after ECMO, and clinical response to the culture results. A total of 2,423 cultures were obtained during 1,487 days of ECMO, of which 155 were positive (6.4%): 13 of 1,370 blood cultures (0.9%), 137 of 850 tracheal aspirate cultures (16%), and 5 of 203 urine cultures (2.3%). After 72 hours, tracheal aspirate cultures became positive with nosocomial organisms in 33 of 131 patients. None of 153 bacterial urine cultures were positive, and only one of 34 viral urine cultures were positive (CMV). We conclude that routine daily blood cultures are not useful in neonatal ECMO. Tracheal aspirate cultures may be helpful in the management of antibiotic therapy in patients on ECMO for more than 5 days. Routine bacterial urine cultures did not provide useful information.

Mechanical Cardiopulmonary Support of Infants and Children With Congenital Heart Disease

Cardiac indications for the use of mechanical cardiopulmo nary support techniques in infants and children include short-term circulatory support during reversible myocardial failure, cardiopulmonary support before and after cardiac surgery, and a bridge to cardiac transplantation. For practi cal purposes, 3 modalities are currently available for these patients: extracorporeal membrane oxygenation, use of ven tricular assist devices, and intra-aortic balloon pump coun terpulsation. Although a variety of devices are available for larger patients, the need for smaller sizes and a wider range of sizes has delayed their use in children. This article sum marizes the current systems available for children as well as indications and outcome data related to their use in infants and children with congenital or acquired heart disease. Copyright © 2001 by W.B. Saunders Company.