Infections in patients with burn injuries receiving extracorporeal membrane oxygenation

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Infectious diseases and infection control prevention strategies in adult and pediatric population on ECMO

As survival after ECMO improves and use of ECMO support increases in both pediatric and adult population, there is a need to focus on both the morbidities and complications associated with ECMO and how to manage and prevent them. Infectious complications during ECMO often have a significant clinical impact, resulting in increased morbidity or mortality irrespective of the underlying etiology necessitating cardiorespiratory support. In this review article, we discuss the prevention, management, challenges, and differences of infectious complications in adult and pediatric patients receiving ECMO support.

Efficacy and safety of extracorporeal membrane oxygenation for burn patients: a comprehensive systematic review and meta-analysis

BACKGROUND

Respiratory and circulatory dysfunction are common complications and the leading causes of death among burn patients, especially in severe burns and inhalation injury. Recently, extracorporeal membrane oxygenation (ECMO) has been increasingly applied in burn patients. However, current clinical evidence is weak and conflicting. This study aimed to comprehensively evaluate the efficacy and safety of ECMO in burn patients.

METHODS

A comprehensive search of PubMed, Web of Science and Embase from inception to 18 March 2022 was performed to identify clinical studies on ECMO in burn patients. The main outcome was in-hospital mortality. Secondary outcomes included successful weaning from ECMO and complications associated with ECMO. Meta-analysis, meta-regression and subgroup analyses were conducted to pool the clinical efficacy and identify influencing factors.

RESULTS

Fifteen retrospective studies with 318 patients were finally included, without any control groups. The commonest indication for ECMO was severe acute respiratory distress syndrome (42.1%). Veno-venous ECMO was the commonest mode (75.29%). Pooled in-hospital mortality was 49% [95% confidence interval (CI) 41-58%] in the total population, 55% in adults and 35% in pediatrics. Meta-regression and subgroup analysis found that mortality significantly increased with inhalation injury but decreased with ECMO duration. For studies with percentage inhalation injury ≥50%, pooled mortality (55%, 95% CI 40-70%) was higher than in studies with percentage inhalation injury <50% (32%, 95% CI 18-46%). For studies with ECMO duration ≥10 days, pooled mortality (31%, 95% CI 20-43%) was lower than in studies with ECMO duration <10 days (61%, 95% CI 46-76%). In minor and major burns, pooled mortality was lower than in severe burns. Pooled percentage of successful weaning from ECMO was 65% (95% CI 46-84%) and inversely correlated with burn area. The overall rate of ECMO-related complications was 67.46%, and infection (30.77%) and bleedings (23.08%) were the two most common complications. About 49.26% of patients required continuous renal replacement therapy.

CONCLUSIONS

ECMO seems to be an appropriate rescue therapy for burn patients despite the relatively high mortality and complication rate. Inhalation injury, burn area and ECMO duration are the main factors influencing clinical outcomes.

Infections complicating extracorporeal membrane oxygenation in patients with traumatic injuries

INTRODUCTION

Extracorporeal Membrane Oxygenation (ECMO) has increasing utility in adult patients with traumatic injuries. There is currently limited data on the pathogens complicating a trauma patient's ECMO course, making empiric antibiotic decisions difficult. This study aims to characterize the types of infection among patients with traumatic injuries on ECMO.

METHODS

A chart review was performed on all trauma patients at Brooke Army Medical Center receiving ECMO between February 2013 and July 2021. Charts were reviewed to identify pathogens by culture site as well as time to infection following cannulation.

RESULTS

Twenty-one trauma patients underwent ECMO during the study period. The majority of patients were men (90%) with a median age of 30 [IQR 27-38], and a median ECMO course of 9.8 days [IQR 3.9-14.1]. Motor vehicle crashes (81%) accounted for the majority of mechanisms of injury. Of the 24 infections, the majority were respiratory (n = 13, 58/1000 ECMO days) followed by skin and soft tissue (n = 6, 26/1000 ECMO days), blood stream (n = 4, 18/1000 ECMO days), and urinary tract (n = 1, 5/1000 ECMO days). Gram-negative bacteria were the most commonly isolated organism from all sites and at all time periods following cannulation. Multi-drug resistant organisms accounted for 35% (n = 9) of infections and were independent of time from cannulation.

DISCUSSION/CONCLUSION

This is the first study to describe infections in trauma patients requiring ECMO support. We observed majority Gram-negative infections regardless of culture site or time after cannulation. Thus, with infection in this population, empiric antibiotics should have broad spectrum coverage of Gram-negative organisms.

Extracorporeal Membrane Oxygenation in Acute Respiratory Distress Syndrome Caused by Anhydrous Ammonia Burns: Two Case Reports

Acute anhydrous ammonia burns are relatively rare but lethal and often occur as a mass occupational incident worldwide. Anhydrous ammonia mainly leads to severe inhalation injury and skin/mucosa wound because of its high water solubility and strong alkalinity. Acute respiratory distress syndrome (ARDS) induced by inhalation injury is the main cause of death. Extracorporeal membrane oxygenation (ECMO), also known as extracorporeal life support, has been recommended as the salvage treatment for severe ARDS based on low-level evidence. However, the application of ECMO in ammonia burns is still limited. Here, we presented two cases of anhydrous ammonia burn patients, one 62-year-old man with 15% total body surface area (TBSA) and one 47-year-old man with 27% TBSA, accompanying severe inhalation injury. They both developed severe ARDS and started vv ECMO on 3, 6, and 15 days after injury, respectively. ECMO lasted 118, 247, and 72 h, respectively. All ECMO were successfully weaned off although only one patient survived. Meanwhile, one patient had the coagulopathy complication of ECMO, mainly bleeding, deep vein thrombosis, and hemolysis. In conclusion, this report provided evidence for use of ECMO as supportive care in ammonia burn patients with severe ARDS.

The Use of Extracorporeal Membrane Oxygenation for Burns: A Systematic Review and Meta-Analysis

Burns are among the leading causes of trauma worldwide, and acute respiratory distress syndrome (ARDS) is a common cause of death in burn patients. Some patients develop hypoxemia refractory to conventional therapies and may be initiated on extracorporeal membrane oxygenation (ECMO) as rescue therapy. We conducted a meta-analysis for studies reporting on survival rates of patients receiving ECMO for burns or inhalation injuries, which was the primary outcome. Secondary outcomes included the hospital and intensive care unit length of stay and duration of ECMO. Random-effects (DerSimonian and Laird) were conducted. The pooled survival from 10 studies was 53.6% (95% confidence interval [CI]: 37.6-69.2%, high certainty). Survival was significantly associated with age (regression coefficient [B]: -0.0088, 95% CI: -0.0155 to -0.0021, p = 0.011) and the proportion of male patients (B: -1.0137 95% CI: -1.9695 to -0.0580, p = 0.038). Patients were cannulated on ECMO for a mean of 8.4 days (95% CI: 6.1-10.7) and remained in the ICU for a mean of 40.4 days (95% CI: 11.4-69.3). Mean hospital length of stay was 45.4 days (95% CI: 31.7-59.0). In conclusion, patients with burn and inhalation injuries who develop ARDS refractory to conservative management have a survival rate of 54% when placed on ECMO.

Extracorporeal Life Support for Severely Burned Patients with Concurrent Inhalation Injury and Acute Respiratory Distress Syndrome: Experience from a Military Medical Burn Center

BACKGROUND

Both inhalation injury and acute respiratory distress syndrome (ARDS) are risk factors that predict mortality in severely burned patients. Extracorporeal life support (ECLS) is widely used to rescue these patients; however, its efficacy and safety in this critical population have not been well defined. We report our experience of using ECLS for the treatment of severely burned patients with concurrent inhalation injury and ARDS.

METHODS

This was a retrospective analysis of 14 patients collected from a single medical burn center from 2012 to 2019. All patients suffered from major burns with inhalation injury and ARDS, and were treated with ECLS.

RESULTS

The median total body surface area of deep dermal or full thickness burns was 94.5%, ranging 47.7-99.0 %. The median revised Baux score was 122.0, ranging 90.0-155.0. All patients developed ARDS with a median partial pressure of arterial oxygen to a fraction of inspired oxygen ratio of 61.5, ranging 49.0-99.0. Indications for ECLS included sustained hypoxemia and unstable hemodynamics. The median interval for initiating ECLS was 2.5 days, ranging 1.0-156.0 days. The median duration of ECLS was 2.9 days, ranging 0.3-16.7 days. The overall survival to discharge was 42.8%. Causes of death included sepsis and multiple organ failure. ECLS-related complications included cannulation bleeding, catheter-related infection, and hemolysis. The incidence of risk factors reported in literature were higher in non-survivors, including Baux>120, albumin < 3.0 g/dL, and lactate > 8 mmol/L.

CONCLUSIONS

For severely burned patients with concurrent inhalation injury and ARDS, ECLS could be a salvage treatment to improve sustained hypoxemia. However, the efficacy of hemodynamic support was limited. Identifying definite ECLS indications and rigorous patient selection would contribute to better clinical outcomes.

A Systematic Review and Meta-Analysis of Extracorporeal Membrane Oxygenation in Patients with Burns

BACKGROUND

Severely burned patients are at high risk for cardiopulmonary failure. Promising studies have stimulated interest in using extracorporeal membrane oxygenation as a potential therapy for burn patients with refractory cardiac and/or respiratory failure. However, the findings from previous studies vary.

METHODS

In this study, the authors conducted a systematic review and meta-analysis using standardized mortality ratios to elucidate the benefits associated with the use of extracorporeal membrane oxygenation in patients with burn and/or inhalation injuries. A literature search was performed, and clinical outcomes in the selected studies were compared.

RESULTS

The meta-analysis found that the observed mortality was significantly higher than the predicted mortality in patients receiving extracorporeal membrane oxygenation (standardized mortality ratio, 2.07; 95 percent CI, 1.04 to 4.14). However, the subgroup of burn patients with inhalation injuries had lower mortality rates compared to their predicted mortality rates (standardized mortality ratio, 0.95; 95 percent CI, 0.52 to 1.73). Other subgroup analyses reported no benefits from extracorporeal membrane oxygenation; however, these results were not statistically significant. Interestingly, the pooled standardized mortality ratio values decreased as the selected patients' revised Baux scores increased (R = -0.92), indicating that the potential benefits from the treatment increased as the severity of patients with burns increased.

CONCLUSIONS

The authors' meta-analysis revealed that burn patients receiving extracorporeal membrane oxygenation treatment were at a higher risk of death. However, select patients, including those with inhalation injuries and those with revised Baux scores over 90, would benefit from the treatment. The authors suggest that burn patients with inhalation injuries or with revised Baux scores exceeding 90 should be considered for the treatment and early transfer to an extracorporeal membrane oxygenation center.

Rates of nosocomial infection associated with interhospital transfer of patients receiving extracorporeal membrane oxygenation

OBJECTIVES

Critically ill patients requiring extracorporeal membrane oxygenation (ECMO) frequently require interhospital transfer to a center that has ECMO capabilities. Patients receiving ECMO were evaluated to determine whether interhospital transfer was a risk factor for subsequent development of a nosocomial infection.

DESIGN

Retrospective cohort study.

SETTING

A 425-bed academic tertiary-care hospital.

PATIENTS

All adult patients who received ECMO for >48 hours between May 2012 and May 2020.

METHODS

The rate of nosocomial infections for patients receiving ECMO was compared between patients who were cannulated at the ECMO center and patients who were cannulated at a hospital without ECMO capabilities and transported to the ECMO center for further care. Additionally, time to infection, organisms responsible for infection, and site of infection were compared.

RESULTS

In total, 123 patients were included in analysis. For the primary outcome of nosocomial infection, there was no difference in number of infections per 1,000 ECMO days (25.4 vs 29.4; P = .03) by univariate analysis. By Cox proportional hazard analysis, transport was not significantly associated with increased infections (hazard ratio, 1.7; 95% confidence interval, 0.8-4.2; P = .20).

CONCLUSION

In this study, we did not identify an increased risk of nosocomial infection during subsequent hospitalization. Further studies are needed to identify sources of nosocomial infection in this high-risk population.

The Use of Extracorporeal Membrane Oxygenation in Severely Burned Patients: A Survey of North American Burn Centers

Respiratory failure and acute respiratory distress syndrome can occur in burn patients with or without inhalational injury, and can significantly increase mortality. For patients with severe respiratory failure who fail conventional therapy with mechanical ventilation, the use of veno-venous extracorporeal membrane oxygen (ECMO) may be a lifesaving salvage therapy. There have been a series of case reports detailing the use of ECMO in burn patients over the last twenty years, but very little is currently known about the status of ECMO use at burn centers in North America. Using a web-based survey of burn center directors in Canada and the United States, we examined the rate of usage of ECMO in burn care, barriers to its use, and the perioperative management of burn patients receiving ECMO therapy. Our findings indicate that approximately half of burn centers have used ECMO in the care of burn patients, but patient volume is very low on average (less than 1 per year). Of centers that do use ECMO in burn care, only 40% have a specified protocol for doing so. Approximately half have operated on patients being actively treated with ECMO therapy, but perioperative management of anticoagulation varies widely. A lack of experience and institutional support, and a perceived lack of evidence to support ECMO use in burn patients were the most commonly identified barriers to more widespread uptake. Better collaboration between burn centers will allow for the creation of consensus statements and protocols to improve outcomes for burn patients who require ECMO.