Risk factors for nosocomial infection during extracorporeal membrane oxygenation

Recent advances in venovenous extracorporeal membrane oxygenation for severe acute respiratory distress syndrome

PURPOSE OF REVIEW

To summarize results of the most recent trials on venovenous extracorporeal membrane oxygenation (VV-ECMO) in severe acute respiratory distress syndrome (ARDS) and to elaborate on the unmet needs regarding VV-ECMO management in this setting.

RECENT FINDINGS

Although it was terminated early for futility (i.e., failure to demonstrate a difference in 60-day mortality of 20%), the ECMO to Rescue Lung Injury in Severe ARDS trial of VV-ECMO for severe ARDS reported a nonsignificant, but clinically important, reduction in mortality (35 vs. 46%; relative risk 0.76; 95% confidence interval 0.55-1.04, P = 0.09). Refractory hypoxemia led to rescue ECMO in 28% of controls, who had more severe ARDS at inclusion, were extremely sick at the time of ECMO cannulation and for whom mortality was 57%. Beyond the rescue of patients dying of refractory hypoxemia, ECMO may now be used early in severe ARDS patients to reduce the intensity of mechanical ventilation and to minimize ventilator-induced lung injury. Future research in the field should focus on identification of patients who are more likely to benefit from this technique and the right timing for its initiation, optimization of daily management of patients under ECMO to further reduce complications, and selection of optimal ventilator management on ECMO.

SUMMARY

VV-ECMO is a reasonable therapeutic option for patients with severe ARDS and major hypoxemia or excessive pressures. Future trials should be designed to optimize patients' management while on VV-ECMO support.

Cannula and circuit management in peripheral extracorporeal membrane oxygenation: An international survey of 45 countries

Effective and safe practices during extracorporeal membrane oxygenation (ECMO) including infection precautions and securement of lines (cannulas and circuits) are critical to prevent life-threatening patient complications, yet little is known about the practices of bedside clinicians and data to support best practice is lacking. Therefore, the aim of this study was to identify and describe common line-related practices for patients supported by peripheral ECMO worldwide and to highlight any gaps for further investigation. An electronic survey was conducted to examine common line practices for patients managed on peripheral ECMO. Responses were obtained from 45 countries with the majority from the United States (n = 181) and United Kingdom (n = 32). Standardised infection precautions including hand hygiene, maximal barrier precautions and skin antisepsis were commonplace for cannulation. The most common antisepsis strategies included alcohol-based chlorhexidine gluconate (CHG) for cannula insertion (53%) and maintenance (54%), isopropyl alcohol on circuit access ports (39%), and CHG-impregnated dressings to cover insertion sites (36%). Adverse patient events due to line malposition or dislodgement were reported by 34% of respondents with most attributable to ineffective securement. Centres 'always' suturing peripheral cannula sites were more likely to experience a cannula adverse event than centres that 'never' sutured (35% [95% CI 30, 41] vs 0% [95% CI 0, 28]; Chi-square 4.40; p = 0.04) but this did not meet the a priori significance level of <0.01. An evidence-based guideline would be beneficial to improve ECMO line management according to 78% of respondents. Evidence gaps were identified for antiseptic agents, dressing products and regimens, securement methods, and needleless valves. Future research addressing these areas may provide opportunities for consensus guideline development and practice improvement.

Gastrointestinal colonization with multidrug-resistant Gram-negative bacteria during extracorporeal membrane oxygenation: effect on the risk of subsequent infections and impact on patient outcome

Background

In ICU patients, digestive tract colonization by multidrug-resistant (MDR) Gram-negative (G−) bacteria is a significant risk factor for the development of infections. In patients undergoing extracorporeal membrane oxygenation (ECMO), colonization by MDR bacteria and risk of subsequent nosocomial infections (NIs) have not been studied yet. The aim of this study is to evaluate the incidence, etiology, risk factors, impact on outcome of gastrointestinal colonization by MDR G− bacteria, and risk of subsequent infections in patients undergoing ECMO.

Methods

This is a retrospective analysis of prospectively collected data: 105 consecutive patients, treated with ECMO, were admitted to the ICU of an Italian tertiary referral center (San Gerardo Hospital, Monza, Italy) from January 2010 to November 2015. Rectal swabs for MDR G− bacteria were cultured at admission and twice a week. Only colonization and NIs by MDR G− bacteria were analyzed.

Results

Ninety-one included patients [48.5 (37–56) years old, 63% male, simplified acute physiology score II 37 (32–47)] underwent peripheral ECMO (87% veno-venous) for medical indications (79% ARDS). Nineteen (21%) patients were colonized by MDR G− bacteria. Male gender (OR 4.03, p = 0.029) and duration of mechanical ventilation (MV) before ECMO > 3 days (OR 3.57, p = 0.014) were associated with increased risk of colonization. Colonized patients had increased odds of infections by the colonizing germs (84% vs. 29%, p < 0.001, OR 12.9), longer ICU length of stay (LOS) (43 vs. 24 days, p = 0.002), MV (50 vs. 22 days, p < 0.001) and ECMO (28 vs. 12 days, p < 0.001), but did not have higher risk of death (survival rate 58% vs. 67%, p = 0.480, OR 0.68). Infected patients had almost halved ICU survival (46% vs. 78%, p < 0.001, OR 4.11).

Conclusions

In patients undergoing ECMO for respiratory and/or circulatory failure, colonization by MDR G− bacteria is frequent and associated with more the tenfold odds for subsequent infection. Those infections are associated with an increased risk of death.

Infections in patients with burn injuries receiving extracorporeal membrane oxygenation

INTRODUCTION

Extracorporeal Membrane Oxygenation (ECMO) has only recently been described in patients with burn injuries. We report the incidence and type of infections in critically ill burn and non-burn patients receiving ECMO.

METHODS

A retrospective chart review was performed on all patients at Brooke Army Medical Center who received ECMO between September 2012 and May 2018.

RESULTS

78 patients underwent ECMO. Approximately half were men with a median age of 34 years with a median time on ECMO of 237 h (IQR 121-391). Compared to patients without burns (n = 58), patients with burns (n = 20) had no difference in time on ECMO, but had more overall infections (86 vs. 31 per 1000 days, p = 0.0002), respiratory infections (40 vs. 15 per 1000 days, p = 0.01), skin and soft tissue infections (21 vs. 5 per 1000 days, p = 0.02) and fungal infections (35% vs 10%, p = 0.02). Twenty percent of bacterial burn infections were due to drug resistant organisms.

CONCLUSION

This is the first study to describe the incidence of infection in burn injury patients who are undergoing ECMO. We observed an increase in infections in burn patients on ECMO compared to non-burn patients. ECMO remains a viable option for critically ill patients with burn injuries.

Nosocomial infection prevalence in patients undergoing extracorporeal membrane oxygenation (ECMO): protocol for a point prevalence study across Australia and New Zealand

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) provides cardiac and/or respiratory support when other therapies fail. Nosocomial infection is reported in up to 64% of patients receiving ECMO and increases morbidity and mortality. These patients are at high risk of infection due, in part, to the multiple invasive devices required in their management, the largest being the cannulae through which ECMO is delivered. Prevalence of nosocomial infection in ECMO patients, including ECMO cannula-related infection, is not well described across Australia and New Zealand.

METHODS AND ANALYSIS

This is a prospective, observational point prevalence study of 12 months duration conducted at 11 ECMO centres across Australia and New Zealand. Data will be collected for every patient receiving ECMO during 12 predetermined data collection weeks. The primary outcome is the prevalence of laboratory-confirmed bloodstream infection, and suspected or probable nosocomial infections; and the secondary outcomes include describing ECMO cannula dressing and securement practices, and adherence to local dressing and securement guidelines. Data collection will be finalised by March 2019.

ETHICS AND DISSEMINATION

Relevant ethical and governance approvals have been received. Study results will describe the prevalence of suspected and confirmed nosocomial infection in adult, paediatric and neonatal patients receiving ECMO across Australia and New Zealand. It is expected that the results will be hypothesis generating and lead to interventional trials aimed at reducing the high infection rates seen in this cohort. Results will be published in peer-reviewed journals and presented at relevant conferences.

TRIAL REGISTRATION NUMBER

ANZCTRN12618001109291; Pre-results.

Infections on Extracorporeal Life Support in Adults and Children-A Survey of International Practice on Prevention, Diagnosis, and Treatment

OBJECTIVES

To assess nosocomial infection management practices in pediatric and adult patients supported with extracorporeal life support.

DESIGN

A 23-question online survey was developed to assess practices related to infection prevention, surveillance, diagnosis, and treatment in patients managed on extracorporeal life support. The survey was distributed internationally to intensivists via online newsletters and e-mail from June to December 2017.

SETTING

Extracorporeal life support centers.

SUBJECTS

Intensivists working in extracorporeal life support centers.

INTERVENTIONS

None.

RESULTS

We analyzed 147 responses from 25 countries. Most centers have bundles implemented as standard of care to prevent against ventilator-associated pneumonia (77%) and central catheter-associated bloodstream infections (91%). Prophylactic antibiotics beyond cannulation are at least occasionally used by 61% of respondents. Daily C-reactive protein (35%) and white cell count (80%) are the most commonly used surveillance biomarkers, and 25% of respondents reported collecting daily surveillance cultures. Participants responded that new onset of hemodynamic instability and rising C-reactive protein (49%) or rising procalcitonin (30%) are the most common triggers to commence antibiotics.

CONCLUSION

There is considerable variability surrounding practices on prevention and diagnosis of infection in patients treated with extracorporeal life support. In view of the impact of infections acquired during extracorporeal life support, further research to inform recommendations on prevention, diagnosis, and management of infection on extracorporeal life support is urgently needed.

The Evaluation of Nosocomial Infections in Pediatric Patients with Extracorporeal Membrane Oxygenation Support

Introduction

Extracorporeal membrane oxygenation (ECMO) has become a standard technique over the past few decades in intensive care unit (ICU).

Objective

A review of pediatric patients who received ECMO support in the pediatric cardiac ICU was conducted to determine the incidence, risk factors and causal organisms related to acquired infections and assess the survival rates of ECMO patients with nosocomial infections.

Methods

Sixty-six patients who received ECMO support in the pediatric cardiac ICU between January 2011 and June 2014 were included in the study. Demographic, echocardiographic, hemodynamic features and surgical procedures were reviewed.

Results

Sixty-six patients received a total of 292.5 days of venoarterial ECMO support. Sixty were postoperative patients. Forty-five patients were weaned from ECMO support with an ECMO survival rate of 68.2%. The rate of infection was 116.2/1000 ECMO days. Prolonged ICU stay, duration of ventilation and ECMO were found associated with development of nosocomial infection and only the duration of ECMO was an independent risk factor for nosocomial infections in ECMO patients.

Conclusion

The correction of the underlying process leading to ECMO support and shortening the length of ECMO duration together with stricter application of ECMO indications would improve the infection incidence and hospital surveillance of the patient group.

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.

Clinical complications during veno-arterial extracorporeal membrane oxigenation in post-cardiotomy and non post-cardiotomy shock: still the achille's heel

Extracorporeal membrane oxygenation (ECMO) is life-saving for potentially reversible heart failure and respiratory injuries not responsive to conventional therapies. Technological innovations have produced over the years significant improvements in ECMO devices (pump, cannula design and oxygenator) and have allowed a better risk/benefit profile. Alongside with recognized advantages in the treatment of very sick patients, ECMO remains an invasive procedure for mechanical circulatory support (MCS) and it is associated with complications that strongly influence the prognosis. Current review was designed to provide a comprehensive outline on ECMO complications, analyzing risk factors and strategies of management, focusing on adult population undergoing veno-arterial ECMO (VA-ECMO) therapy.

Ventilator-associated pneumonia in extracorporeal membrane oxygenation-assisted patients

Extracorporeal membrane oxygenation (ECMO) provides a circulatory and/or respiratory assistance in case of refractory cardiogenic shock or acute respiratory distress syndrome (ARDS). Due to their extreme critical illness, these patients usually require prolonged mechanical ventilation, which is an inherent risk of ventilator-associated pneumonia (VAP). Although microorganisms responsible of VAP on ECMO are similar to those found in non-ECMO patients, classical suspicion criteria of VAP are no longer relevant on ECMO. Frequent severe chest X-Ray impairments, and poor specificity of the classical biomarkers on ECMO make VAP diagnosis challenging. In addition, significant drug pharmacokinetic modifications by the device may lead to low plasmatic antibiotic concentration and potential treatment failure. Consequently, rate of treatment failure and relapse appear high in that population (up to 30%), with significant impact on mortality and on the ECMO duration.

Incidence of nosocomial infections in adult patients undergoing extracorporeal membrane oxygenation

INTRODUCTION

Critically ill patients requiring extracorporeal membrane oxygenation (ECMO) are at increased risk for developing nosocomial infections owing to their underlying disease process along with numerous invasive monitoring devices.

METHODS

We retrospectively analyzed the rate, type, pathogens, outcomes, and risk factors of nosocomial infections that developed during adult patients on ECMO at our institution from 2012-2015.

RESULTS

Compared to current ELSO reported adult nosocomial infections rate of 20.5%, we report our rate of 26% (CI 17.2%-34.7%). No significant differences were observed in mortality (42.3% vs. 36.5%; p=0.598), and presence of either antibiotics prior to ECMO (57.7% vs. 56.7%; p=0.934) or culture-proven infection prior to ECMO (19.2% vs. 32.4%; p=0.201). Patients who developed nosocomial infections had longer duration of ECMO (13 vs. 5 days; p<0.001), longer length of stay (36.5 vs. 18.5 days; p=0.004), and more days on ventilator (29 vs. 12.5; p=0.002). Duration of ECMO (OR=1.20, 95% CI 1.02-1.39; p=0.020) and duration of ECMO greater than 10 days (OR=14.65, 95% CI 1.81-118.78; p=0.012) were independent risk factors for developing nosocomial infections. However, there was no difference in mortality when duration of ECMO >10 days was compared with ≤10 days (28.5% vs. 43.1%; p=0.154).

CONCLUSION

Nosocomial infections have no effect on survival in adult ECMO patients. Presence of either antibiotics or infection prior to ECMO has no effect on developing nosocomial infections while on ECMO. Duration of ECMO longer than 10 days is a major risk factor for developing nosocomial infection.

Blood Stream Infection in Patients on Venovenous Extracorporeal Membrane Oxygenation for Respiratory Failure

Bloodstream infection (BSI) occurred in 21 of 121 patients (17%) receiving venovenous extracorporeal membrane oxygenation within the median time of 6 days after initiation (interquartile range, 4-19 days). Longer duration of arterial catheterization and more blood transfusions were independently associated with BSI, which is associated with poor clinical outcomes.Infect Control Hosp Epidemiol 2018;1-4.

Idiopathic pulmonary fibrosis patient supported with extracorporeal membrane oxygenation for 403 days while waiting for a lung transplant: A case report

According to the Extracorporeal Life Support Organization, the average duration of veno-venous extracorporeal membrane oxygenation (V-V ECMO) in adults with acute respiratory failure is 10.5-13.5 days. Some patients on V-V ECMO may not recover in such a short period of time, and recently, there have been more reports of prolonged V-V ECMO. However, we do not know how long it is feasible to wait for native lung recovery or lung transplant (LTx) with the use of ECMO. We describe a patient with acute exacerbation of idiopathic pulmonary fibrosis supported by ECMO for 403 days while waiting for a LTx. In this case, we kept the patient awake, and he was communicating frequently with his family. We changed the membrane oxygenator 23 times and the cannula 10 times without complication. However, we terminated the treatment on day 403 of ECMO because there was no access site for cannula insertion due to blockage by a venous thrombotic occlusion, making it impossible to continue this bridge to lung transplantation. It has become possible to maintain patients on ECMO for extended periods of time, but it is difficult to manage ECMO for more than one year without the development of a more durable lung support system.

Extracorporeal membrane oxygenation line-associated complications: in vitro testing of cyanoacrylate tissue adhesive and securement devices to prevent infection and dislodgement

Background

Extracorporeal membrane oxygenation (ECMO) delivers cardiac and/or respiratory support to critically ill patients who have failed conventional medical therapies. If the large-bore cannulas used to deliver ECMO become infected or dislodged, the patient consequences can be catastrophic. ECMO cannula-related infection has been reported to be double the rate of other vascular devices (7.1 vs 3.4 episodes/1000 ECMO days respectively). The aim of this study was to assess the ability of cyanoacrylate tissue adhesive (TA) to inhibit bacterial growth at the ECMO cannulation site, and the effectiveness of TA and securement devices in securing ECMO cannulas and tubing.

Methods

This in vitro study tested the (1) antimicrobial qualities of TA against standard transparent dressing with ECMO cannula; (2) chemical compatibility between cannula, TA and removal agent; (3) pull-out strength of transparent dressing and TA at the cannula insertion site; and (4) pull-out strength of adhesive bandage and commercial sutureless securement devices (SSDs) on circuit tubing. Fisher’s exact test was used to evaluate differences in bacterial growth observed between the transparent dressing and TA groups. Data from mechanical testing were analysed using one-way ANOVA, followed by Tukey’s multiple comparison test or t test as appropriate. Statistical significance was defined as p < 0.05.

Results

No bacterial growth occurred under TA-covered cannulas compared with transparent dressing-covered cannulas (p = 0.002). Compared to plates lacking TA or transparent dressing, growth was observed at the insertion point and under the dressing in the transparent dressing group; however, no growth was observed in the TA group (p = 0.019). TA did not weaken the cannulas; however, the TA removal agent did after 60 min of exposure, compared with control (p < 0.01). Compared with transparent dressing, TA increased the pull-out force required for cannula dislodgement from the insertion point (p < 0.0001). SSDs significantly increased the force required to remove the tubing from the fixation points compared with adhesive bandage (p < 0.01).

Conclusions

Our findings suggest that the combined use of TA at the cannula insertion site with a commercial device for tubing securement could provide an effective bedside strategy to prevent or minimise infection and line dislodgement.

Infectious complications in paediatric patients treated with extracorporeal membrane oxygenation

INTRODUCTION

The aim of this study was to analyse the incidence, treatment and evolution of infections in children treated with ECMO.

METHODS

A retrospective study based on a prospective database was performed. Children under the age of 18 years treated with ECMO from September 2006 to November 2015 were included. The patients' clinical characteristics were collected, together with ECMO technique, cultures and treatment of infection.

RESULTS

One hundred patients with a median age of 11 months were analysed. Heart disease was diagnosed in 94 patients. An infection was suspected and antibiotic treatment was initiated in 51 patients, although only 22 of them were microbiologically confirmed. The most common infection was sepsis (49%), followed by pneumonia (35.3%) and urinary tract infection (9.8%). There were no differences in haematological parameters and acute phase reactants between children with infection and those without. Children who died had a higher incidence of infection during ECMO (60.4%) than the survivors (40.3%), but the difference did not reach statistical significance (P=.07). The duration of admission in the PICU was 57 days in patients with infection vs 37 days in patients without infection but the difference was not statistically significant (P=.067).

CONCLUSIONS

Infection in children with ECMO is common. There are no specific infection parameters and less than half of the clinical infections are confirmed microbiologically. There was no statistically significant correlation between infection and mortality or duration of PICU stay.

Nosocomial Infections During Extracorporeal Membrane Oxygenation: Incidence, Etiology, and Impact on Patients' Outcome

OBJECTIVE

To study incidence, type, etiology, risk factors, and impact on outcome of nosocomial infections during extracorporeal membrane oxygenation.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

Italian tertiary referral center medical-surgical ICU.

PATIENTS

One hundred five consecutive patients who were treated with extracorporeal membrane oxygenation from January 2010 to November 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Ninety-two patients were included in the analysis (48.5 [37-56] years old, simplified acute physiology score II 37 [32-47]) who underwent peripheral extracorporeal membrane oxygenation (87% veno-venous) for medical indications (78% acute respiratory distress syndrome). Fifty-two patients (55%) were infected (50.4 infections/1,000 person-days of extracorporeal membrane oxygenation). We identified 32 ventilator-associated pneumonia, eight urinary tract infections, five blood stream infections, three catheter-related blood stream infections, two colitis, one extracorporeal membrane oxygenation cannula infection, and one pulmonary-catheter infection. G+ infections (35%) occurred earlier compared with G- (48%) (4 [2-10] vs. 13 [7-23] days from extracorporeal membrane oxygenation initiation; p < 0.001). Multidrug-resistant organisms caused 56% of bacterial infections. Younger age (2-35 years old) was independently associated with higher risk for nosocomial infections. Twenty-nine patients (31.5%) died (13.0 deaths/1,000 person-days of extracorporeal membrane oxygenation). Infected patients had higher risk for death (18 vs. 8 deaths/1,000 person-days of extracorporeal membrane oxygenation; p = 0.037) and longer ICU stay (32.5 [19.5-78] vs. 19 [10.5-27.5] days; p = 0.003), mechanical ventilation (36.5 [20-80.5] vs. 16.5 [9-25.5] days; p < 0.001), and extracorporeal membrane oxygenation (25.5 [10.75-54] vs. 10 [5-13] days; p < 0.001). Older age (> 50 years old), reason for connection different from acute respiratory distress syndrome, higher simplified acute physiology score II, diagnosis of ventilator-associated pneumonia, and infection by multidrug-resistant bacteria were independently associated to increased death rate.

CONCLUSIONS

Infections (especially ventilator-associated pneumonia) during extracorporeal membrane oxygenation therapy are common and frequently involve multidrug-resistant organisms. In addition, they have a negative impact on patients' outcomes.

Population Pharmacokinetics and Dose Optimization of Teicoplanin during Venoarterial Extracorporeal Membrane Oxygenation

The pharmacokinetics (PK) of drugs are known to be significantly altered in patients receiving extracorporeal membrane oxygenation (ECMO). However, clinical studies of the PK of drugs administered during ECMO are scarce, and the proper dosing adjustment has yet to be established. We developed a population PK model for teicoplanin, investigated covariates influencing teicoplanin exposure, and suggested an optimal dosing regimen for ECMO patients. Samples for PK analysis were collected from 10 adult patients, and a population PK analysis and simulations were performed to identify an optimal teicoplanin dose needed to provide a >50% probability of target attainment at 72 h using a trough concentration target of >10 μg/ml for mild to moderate infections and a trough concentration target of >15 μg/ml for severe infections. Teicoplanin was well described by a two-compartment PK model with first-order elimination. The presence of ECMO was associated with a lower central volume of distribution, and continuous renal replacement therapy (CRRT) was associated with a higher peripheral volume of distribution. For mild to moderate infections, an optimal dose was a loading dose (LD) of 600 mg and a maintenance dose (MD) of 400 mg for ECMO patients not receiving CRRT and an LD of 800 mg and an MD of 600 mg for those receiving CRRT. For severe infections, an optimal dose was an LD of 1,000 mg and an MD of 800 mg for ECMO patients not receiving CRRT and an LD of 1,200 mg and an MD of 1,000 mg for those receiving CRRT. In conclusion, doses higher than the standard doses are needed to achieve fast and appropriate teicoplanin exposure during ECMO. (This study has been registered at ClinicalTrials.gov under identifier NCT02581280.).

Outcomes and survival prediction models for severe adult acute respiratory distress syndrome treated with extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS) has known a growing interest over the last decades with promising results during the 2009 A(H1N1) influenza epidemic. Targeting populations that can most benefit from this therapy is now of major importance.

Survival has steadily improved for a decade, reaching up to 65% at hospital discharge in the most recent cohorts. However, ECMO is still marred by frequent and significant complications such as bleeding and nosocomial infections. In addition, physiological and psychological symptoms are commonly described in long-term follow-up of ECMO-treated ARDS survivors. Because this therapy is costly and exposes patients to significant complications, seven prediction models have been developed recently to help clinicians identify patients most likely to survive once ECMO has been initiated and to facilitate appropriate comparison of risk-adjusted outcomes between centres and over time. Higher age, immunocompromised status, associated extra-pulmonary organ dysfunction, low respiratory compliance and non-influenzae diagnosis seem to be the main determinants of poorer outcome.

Delayed extracorporeal membrane oxygenation in children after cardiac surgery: two-institution experience

OBJECTIVE

There are limited data on the outcomes of children receiving delayed (≥7 days) extracorporeal membrane oxygenation after cardiac surgery. The primary aim of this project is to identify the aetiology and outcomes of extracorporeal membrane oxygenation in children receiving delayed (≥7 days) extracorporeal membrane oxygenation after cardiac surgery.

PATIENTS AND METHODS

We conducted a retrospective review of all children ≤18 years supported with delayed extracorporeal membrane oxygenation after cardiac surgery between the period January, 2001 and March, 2012 at the Arkansas Children's Hospital, United States of America, and Royal Children's Hospital, Australia. The data collected in our study included patient demographic information, diagnoses, extracorporeal membrane oxygenation indication, extracorporeal membrane oxygenation support details, medical and surgical history, laboratory, microbiological, and radiographic data, information on organ dysfunction, complications, and patient outcomes. The outcome variables evaluated in this report included: survival to hospital discharge and current survival with emphasis on neurological, renal, pulmonary, and other end-organ function.

RESULTS

During the study period, 423 patients undergoing cardiac surgery were supported with extracorporeal membrane oxygenation at two institutions, with a survival of 232 patients (55%). Of these, 371 patients received extracorporeal membrane oxygenation <7 days after cardiac surgery, with a survival of 205 (55%) patients, and 52 patients received extracorporeal membrane oxygenation ≥7 days after cardiac surgery, with a survival of 27 (52%) patients. The median duration of extracorporeal membrane oxygenation run for the study cohort was 5 days (interquartile range: 3, 10). In all, 14 patients (25%) received extracorporeal membrane oxygenation during active cardiopulmonary resuscitation with chest compressions. There were 24 patients (44%) who received dialysis while being on extracorporeal membrane oxygenation. There were eight patients (15%) who had positive blood cultures and four patients (7%) who had positive urine cultures while being on extracorporeal membrane oxygenation. There were nine patients (16%) who had bleeding complications associated with extracorporeal membrane oxygenation runs. There were 10 patients (18%) who had cerebrovascular thromboembolic events associated with extracorporeal membrane oxygenation runs. Of these, 19 patients are still alive with significant comorbidities.

CONCLUSIONS

This study demonstrates that mortality outcomes are comparable among children receiving extracorporeal membrane oxygenation ≥7 days and <7 days after cardiac surgery. The proportion of patients receiving extracorporeal membrane oxygenation ≥7 days is small and the aetiology diverse.

Influence of different oxygenator types on changing frequency, infection incidence, and mortality in ARDS patients on veno-venous ECMO

PURPOSE

Veno-venous extracorporeal membrane oxygenation (vv-ECMO) is pivotal in the treatment of patients suffering from acute respiratory distress syndrome (ARDS). Comparative data with different oxygenator models have not yet been reported. The aim of this retrospective investigation was therefore to assess whether different oxygenator types might influence changing frequency, infection incidence, and mortality in patients on vv-ECMO.

METHODS

42 patients undergoing vv-ECMO between 1998 and 2009 were identified. In 20 out of these patients, a polypropylene (PP) microporous hollow fiber membrane oxygenator, and in 22 patients a nonmicroporous polymethylpentene (PMP) diffusion membrane oxygenator was used. Infection incidence, changing frequency, and mortality were documented.

RESULTS

In the PMP group, an oxygenator change was necessary less often than in the PP group (p<0.001). The incidence of bacterial, viral, or fungal growth was similar in the groups, thus independent of the frequency of oxygenator change. Irrespective of the groups, the occurrence of Candida sp. tended to correlate with death (p = 0.06). In general, there was a trend towards a higher infection incidence in the subgroup with pulmonary ARDS (p = 0.07). Moreover, infection incidence was associated with a longer ICU stay (p = 0.03) and longer ECMO therapy (p = 0.03). ICU mortality was lower in the PMP group than in the PP group, although not statistically significant (p = 0.10).

CONCLUSIONS

The PMP oxygenator membranes showed benefits with regards to changing frequency, but not infection incidence, length of ICU stay, and length of ECMO therapy. There was a trend towards a lower ICU mortality in patients with PMP oxygenators.

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.

Invasive pulmonary aspergillosis post extracorporeal membrane oxygenation support and literature review

The use of extracorporeal membrane oxygenation (ECMO) for reversible pulmonary failure in critically ill patients has increased over the last few decades. Nosocomial infections are a major complication of ECMO and fungi have been found to be a common cause. Herein, we describe a case of invasive pulmonary aspergillosis following ECMO, which was successfully treated with combination antifungal therapy and interferon-gamma.

Factors associated with outcomes of patients on extracorporeal membrane oxygenation support: a 5-year cohort study

Introduction

Mortality of patients on extracorporeal membrane oxygenation (ECMO) remains high. The objectives of this study were to assess the factors associated with outcome of patients undergoing ECMO in a large ECMO referral centre and to compare veno-arterial ECMO (VA ECMO) with veno-venous ECMO (VV ECMO).

Methods

We reviewed a prospectively obtained ECMO database and patients' medical records between January 2005 and June 2011. Demographic characteristics, illness severity at admission, ECMO indication, organ failure scores before ECMO and the ECMO mode and configuration were recorded. Bleeding, neurological, vascular and infectious complications that occurred on ECMO were also collected. Demographic, illness, ECMO support descriptors and complications associated with hospital mortality were analysed.

Results

ECMO was initiated 158 times in 151 patients. VA ECMO (66.5%) was twice as common as VV ECMO (33.5%) with a median duration significantly shorter than for VV ECMO (7 days (first and third quartiles: 5; 10 days) versus 10 days (first and third quartiles: 6; 16 days)). The most frequent complications during ECMO support were bleeding and bloodstream infections regardless of ECMO type. More than 70% of the ECMO episodes were successfully weaned in each ECMO group. The overall mortality was 37.3% (37.1% for the patients who underwent VA ECMO, and 37.7% for the patients who underwent VV ECMO). Haemorrhagic events, assessed by the total of red blood cell units received during ECMO, were associated with hospital mortality for both ECMO types.

Conclusions

Among neurologic, vascular, infectious and bleeding events that occurred on ECMO, bleeding was the most frequent and had a significant impact on mortality. Further studies are needed to better investigate bleeding and coagulopathy in these patients. Interventions that reduce these complications may improve outcome.

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.

Nosocomial infections in adult cardiogenic shock patients supported by venoarterial extracorporeal membrane oxygenation

BACKGROUND

Incidence and impact on adult patients' outcomes of nosocomial infections (NIs) occurring during venoarterial extracorporeal membrane oxygenation (VA-ECMO) support for refractory cardiogenic shock have rarely been described.

METHODS

We retrospectively reviewed the charts of a large series of patients who received VA-ECMO in our intensive care unit (ICU) from January 2003 through December 2009. Incidence, types, risk factors, and impact on outcomes of NIs occurring during ECMO support were analyzed.

RESULTS

Among 220 patients (49 ± 16 years old, simplified acute physiology score (SAPS) II 61 ± 20) who underwent ECMO support for >48 hours for a total of 2942 ECMO days, 142 (64%) developed NIs. Ventilator-associated pneumonia (VAP), bloodstream infections, cannula infections, and mediastinitis infections occurred in 55%, 18%, 10% and 11% of the patients, respectively. More critical condition at ICU admission, but not antibiotics at the time of ECMO cannulation, was associated with subsequently developing NIs (hazard ratio, 0.73; 95% confidence interval [CI], .50-1.05; P = .09). Infected patients had longer durations of mechanical ventilation, ECMO support, and hospital stays. Independent predictors of death were infection with severe sepsis or septic shock (odds ratio, 1.93; 95% CI, 1.26-2.94; P = .002) and SAPS II, whereas immunosuppression and myocarditis as the reason for ECMO support were associated with better outcomes.

CONCLUSIONS

Cardiogenic shock patients who received the latest generation VA-ECMO still had a high risk of developing NIs, particularly VAP. Strategies aimed at preventing these infections may improve the outcomes of these critically ill patients.

Trends in and perspectives on extracorporeal membrane oxygenation for severe adult respiratory failure

Various approaches such as ventilator management involving lung-protective ventilation, corticosteroids, prone positioning, and nitric oxide have failed to maintain sufficient lung oxygenation or appropriate ventilation competence in very severe acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) has been aggressively introduced for such patients, although in only a few institutions. The clinical usefulness of ECMO in a large-scale multicenter study (CESAR trial, 2009) and continued development/improvement of ECMO devices have facilitated performance of ECMO, with further increase in the number of institutions adopting ECMO therapy. Clinical usefulness of ECMO was documented in many cases of severe ARDS secondary to influenza A (H1N1) 2009 infection. ECMO requires establishment of an appropriate management system to minimize fatal complications (e.g., hemorrhage), which requires a multidisciplinary team. This, in combination with a new technique, interventional lung assist, will further extend the indications for ECMO. ECMO can be expected to gain importance as a respiratory support technique.

20-year experience of prolonged extracorporeal membrane oxygenation in critically ill children with cardiac or pulmonary failure

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a rescue therapy for life-threatening respiratory or circulatory failure. Although outcomes are favorable with short-term ECMO therapy, data on the outcomes of prolonged ECMO therapy in children are very limited. This study aimed to study morbidity and mortality associated with prolonged ECMO therapy (≥28 days) in children with refractory cardiac or pulmonary failure.

METHODS

We conducted a retrospective review of all children≤18 years supported with ECMO for ≥28 days between January 1991 and September 2011 at the Arkansas Children's Hospital. The data collected in our study included patient demographic information; diagnosis; indication for ECMO; ECMO support details; medical and surgical history; laboratory, microbiologic, and radiographic data; information on organ dysfunction; complications; and patient outcomes. The outcome variables evaluated in this report included survival to ECMO decannulation, survival to hospital discharge, and current survival with emphasis on neurologic, renal, pulmonary, and other end organ function.

RESULTS

During the study period, 984 events in 951 patients were supported with ECMO with a 30-day survival of 666 events (68%). Only 22 ECMO runs were ≥28 days and were eligible for inclusion in this report. The longest ECMO run in our series was 1,206 hours (50 days). The average length of ECMO run in this cohort was 855±133 hours, with a mean intensive care unit length of stay of 56±27 days. Ten patients (45%) were successfully decannulated from ECMO. Six patients (27%) were alive 30 days after decannulation, and only 4 patients (19%) survived to hospital discharge. Of the 4 survivors, only 3 patients (14%) are living to date. Of the 3 living children, 2 have significant neurologic issues with brain atrophy and developmental delay, and 1 is awaiting renal transplant; all 3 survivors have chronic lung disease.

CONCLUSIONS

This case series highlights that the prolonged use of ECMO in children with refractory cardiac failure, respiratory failure, or both is associated with low survival. Furthermore, it suggests that the survivors of prolonged ECMO runs have significant long-term sequelae.

Defining risk for infectious complications on extracorporeal life support

BACKGROUND/PURPOSE

Little is known about potentially modifiable risk factors associated with infectious complications (IC) acquired during extracorporeal life support (ECLS).

PATIENTS AND METHODS

The Extracorporeal Life Support Organization registry was accessed, and data on patient demographics, run characteristics, infections, and outcomes were collected. Patients who developed IC while on ECLS were compared to those that did not. Regression analysis was performed. Results are expressed as odds ratios, with P < .05 considered significant.

RESULTS

Infectious complications developed in 10.2% of 38,661 patients and was associated with increased odds of death. Risk factors for IC included increasing age, diagnosis, more remote decade, complications, presence of multiple complications, and ECLS mode. The risk of IC increased with the number of complications (P < .001). Patients with positive cultures before ECLS also had increased odds of IC (OR 2.12, 95% CI 1.92-2.34, P < .001). Those with IC were more likely to have cultures grow aggressive organisms (non-lactose fermenting gram negative rods, methicillin resistant Staphylococcus aureus, and fungi).

CONCLUSIONS

Strategies to reduce IC while on ECLS should be aimed at prevention of complications and treatment of pre-existing infections. Future studies should address whether broader spectrum antibiotic prophylaxis and/or empiric coverage for suspected sepsis is indicated in ECLS patients.

Prolonged venovenous extracorporeal membrane oxygenation in a child with leukemia and persistent bacteremia

OBJECTIVE

In patients who require extracorporeal membrane oxygenation for prolonged periods, it is uncertain whether nosocomial bacteremia that persists throughout an entire extracorporeal membrane oxygenation run can be associated with good outcomes.

DESIGN

Case report.

SETTING

Tertiary pediatric intensive care unit.

PATIENT

A 6-yr-old boy with acute myeloid leukemia and prolonged mechanical ventilatory support.

INTERVENTIONS

Venovenous extracorporeal membrane oxygenation.

MEASUREMENTS AND MAIN RESULTS

The patient required extracorporeal membrane oxygenation for refractory hypoxia secondary to nosocomial pneumonia. On day 2 of the extracorporeal membrane oxygenation run and every day thereafter, blood cultures were consistently positive for Stenotrophomonas maltophilia despite combination therapy with intravenous polymyxin B and cotrimoxazole. Excluding the cannulae, the extracorporeal membrane oxygenation circuit was electively changed once during the run but without any effect on bacteremia. After 38 days of extracorporeal membrane oxygenation, the patient was successfully decannulated and the bacteremia ceased. He remains completely well and disease-free at 6-month follow-up.

CONCLUSIONS

Sustained bacteremia during an extracorporeal membrane oxygenation run should not be regarded as a reason to withdraw extracorporeal support, although efforts are clearly warranted to identify possible sources of sepsis and wean off extracorporeal membrane oxygenation at the earliest opportunity.

Characteristics of hospital patients colonized with livestock-associated meticillin-resistant Staphylococcus aureus (MRSA) CC398 versus other MRSA clones

Meticillin-resistant Staphylococcus aureus (MRSA) associated with the clonal complex (CC) 398 has emerged among livestock and humans exposed to these animals. MRSA CC398 has so far contributed relatively little to spread of MRSA and the burden of disease in the healthcare setting. This study aimed to assess whether demographic and clinical differences in patients colonized with MRSA CC398 and those carrying other MRSA clones contribute to the observed differences in transmission and infection rates. Age, sex, length of stay (LOS), diagnoses and medical procedures were assessed in all patients with MRSA admitted to a university hospital in 2008 and 2009. S. aureus protein A gene (spa) typing was performed on the first MRSA isolate from each patient. Patients colonized or infected with MRSA that had spa types indicative of CC398 (MRSA CC398) were compared with patients who had other MRSA clones (MRSA non-CC398). Age (53 vs 59 years), mean LOS (8 vs 13 days) and percentage of patients admitted to an intensive care unit (12% vs 17%) differed significantly between MRSA CC398 and MRSA non-CC398 patients, respectively. The mean numbers and types of diagnoses and medical procedures performed for patients in these two groups also differed significantly. The differences in patient characteristics could explain, at least in part, the relatively low rates of transmission and infection associated with MRSA CC398 in the healthcare setting.

Pharmacokinetics of cefotaxime and desacetylcefotaxime in infants during extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is used to temporarily sustain cardiac and respiratory function in critically ill infants but can cause pharmacokinetic changes necessitating dose modifications. Cefotaxime (CTX) is used to prevent and treat infections during ECMO, but the current dose regimen is based on pharmacokinetic data obtained for non-ECMO patients. The objective of this study was to validate the standard dose regimen of 50 mg/kg of body weight twice a day (postnatal age [PNA], <1 week), 50 mg/kg three times a day (PNA, 1 to 4 weeks), or 37.5 mg/kg four times a day (PNA, >4 weeks). We included 37 neonates on ECMO, with a median (range) PNA of 3.3 (0.67 to 199) days and a median (range) body weight of 3.5 (2.0 to 6.2) kg at the onset of ECMO. Median (range) ECMO duration was 108 (16 to 374) h. Plasma samples were taken during routine care, and pharmacokinetic analysis of CTX and its active metabolite, desacetylcefotaxime (DACT), was done using nonlinear mixed-effects modeling (NONMEM). A one-compartment pharmacokinetic model for CTX and DACT adequately described the data. During ECMO, CTX clearance (CL(CTX)) was 0.36 liter/h (range, 0.19 to 0.75 liter/h), the volume of distribution of CTX (V(CTX)) was 1.82 liters (0.73 to 3.02 liters), CL(DACT) was 1.46 liters/h (0.48 to 5.93 liters/h), and V(DACT) was 11.0 liters (2.32 to 28.0 liters). Elimination half-lives for CTX and DACT were 3.5 h (1.6 to 6.8 h) and 5.4 h (0.8 to 14 h). Peak CTX concentration was 98.0 mg/liter (33.2 to 286 mg/liter). DACT concentration varied between 0 and 38.2 mg/liter, with a median of 10 mg/liter in the first 12 h postdose. Overall, CTX concentrations were above the MIC of 8 mg/liter over the entire dose interval. Only 1 of the 37 patients had a sub-MIC concentration for over 50% of the dose interval. In conclusion, the standard cefotaxime dose regimen provides sufficiently long periods of supra-MIC concentrations to provide adequate treatment of infants on ECMO.