Clearance of blood stream infections in patients receiving extracorporeal membrane oxygenation: a retrospective single-center cohort study.

BACKGROUND: There are limited data on the treatment of blood stream infections (BSIs) in patients receiving extracorporeal membrane oxygenation (ECMO). Current guidance recommends documenting clearance only in fungal and Gram-positive BSIs. This study investigates the incidence and clinical significance of blood stream infections with positive repeat cultures (BSIPRC) in ECMO as well as clinical factors that may predict positive repeat cultures. METHODS: All BSIs in patients receiving ECMO at Brooke Army Medical Center between September 2012 and October 2021 were included in this study. BSIPRC was defined as re-isolation of the same organism on repeat blood cultures following an initial positive blood culture. RESULTS: A total of 60 patients developed 87 BSI (38.5 BSI per 1000 ECMO days). Of the 80 (92%) BSIs who had repeat blood cultures drawn, patients had BSIPRC in 35 (44%) of cases. Fever, leukocytosis, and vasopressor requirement on day of repeat culture were not associated with persistent positivity. There was no difference in survival to discharge for patients with BSIPRC as compared to single day BSI (58% vs. 63%, p = 0.78). 19% of patients with Gram-negative bacteremia had BSIPRC, and gram-negative bacteremia in general was associated with an 83% morality. CONCLUSIONS: There were no clinical findings that differentiated patients with BSIPRC from those who had a single day of positivity. BSI was associated with high mortality in patients with Gram-negative bacteremia. Given high incidence of positive repeat cultures being seen in Gram-negative BSIs, repeat blood cultures have utility for all BSIs in patients receiving ECMO.

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.

Adjunct Use of Continuous Renal Replacement Therapy with Extracorporeal Membrane Oxygenation Achieves Negative Fluid Balance and Enhances Oxygenation Which Improves Survival in Critically Ill Patients without Kidney Failure.

INTRODUCTION: Fluid overload in extracorporeal membrane oxygenation (ECMO) patients has been associated with increased mortality. Patients receiving ECMO and continuous renal replacement therapy (CRRT) who achieve a negative fluid balance have improved survival. Limited data exist on the use of CRRT solely for fluid management in ECMO patients. METHODS: We performed a single-center retrospective review of 19 adult ECMO patients without significant renal dysfunction who received CRRT for fluid management. These patients were compared to a cohort of propensity-matched controls. RESULTS: After 72 h, the treatment group had a fluid balance of -3840 mL versus + 425 mL (p ≤ 0.05). This lower fluid balance correlated with survival to discharge (odds ratio 2.54, 95% confidence interval 1.10-5.87). Improvement in the ratio of arterial oxygen content to fraction of inspired oxygen was also significantly higher in the CRRT group (102.4 vs. 0.7, p ≤ 0.05). We did not observe any significant difference in renal outcomes. CONCLUSIONS: The use of CRRT for fluid management is effective and, when resulting in negative fluid balance, improves survival in adult ECMO patients without significant renal dysfunction.

The utility of procalcitonin for identifying secondary infections in patients with influenza or COVID-19 receiving extracorporeal membrane oxygenation.

Background: Identifying secondary infections in patients receiving extracorporeal membrane oxygenation (ECMO) presents challenges due to the ECMO circuit's influence on traditional signs of infection. Objectives: This study evaluates procalcitonin as a diagnostic marker for secondary infections in patients receiving ECMO with influenza or COVID-19 infection. Design: Single-center retrospective cohort study. Methods: All adult patients receiving veno-venous ECMO with underlying influenza or COVID-19 from November 2017 to October 2021 were included. Patient demographics, time receiving ECMO, culture data, and procalcitonin levels were examined. The first procalcitonin within 3 days of infection was compared to negative workups that were collected at least 10 days from the last positive culture. Furthermore, we compared procalcitonin levels by the type of pathogen and site of infection. Results: In this study, 84 patients with influenza or COVID-19 who received ECMO were included. A total of 276 procalcitonin labs were ordered in this cohort, with 33/92 (36%) of the secondary infections having an associated procalcitonin value. When comparing procalcitonin levels, there was no significant difference between the infection and negative workup groups [1 ng/mL (interquartile ranges, IQR: 0.4-1.2) versus 1.3 (0.5-4.3), p = 0.19]. Using 0.5 ng/mL as the cut-off, the sensitivity of procalcitonin was 67% and the specificity was 30%. In our cohort, the positive predictive value of procalcitonin was 14.5% and the negative predictive value was 84%. There was no difference in procalcitonin by type of organism or site of infection. Procalcitonin levels did not routinely decline even after an infection was identified. Conclusion: While procalcitonin is a proposed potential diagnostic marker for secondary infections in patients receiving ECMO, this single-center study demonstrated low sensitivity and specificity of procalcitonin in identifying secondary infections. Furthermore, there was no association of procalcitonin levels with etiology of infection when one was present. Procalcitonin should be used cautiously in identifying infections in veno-venous ECMO.

BACKGROUND: It is very difficult to determine whether patients receiving ECMO have infections as both vital signs and laboratory markers have not shown good utility. Procalcitonin is a laboratory test sometimes used to identify infections, but its test performance is not known in this population. METHODS: We performed a study of adult patient patients receiving ECMO to determine if there were differences in procalcitonin levels when patients had infections as compared to when they did not have infections. We also looked to see if procalcitonin levels routinely dropped after an infection was diagnosed. RESULTS: Procalcitonin values were no different when patients had an infection as compared to when they did not have an infection. Using standard laboratory cut-offs, the procalcitonin sensitivity was 67%, and specificity was 30%. Procalcitonin levels did not routinely decline even after an infection was identified. CONCLUSIONS: Procalcitonin poorly differentiated patients with infections from those without infections and should be used with caution in patients receiving ECMO.

The utility of procalcitonin for identifying secondary infections in patients with influenza or COVID-19 receiving extracorporeal membrane oxygenation Aim: To determine if procalcitonin performs well as a diagnostic marker in identifying additional infections in adult patients receiving ECMO with influenza or COVID-19.

Fever and Leukocytosis Are Poor Predictors of Bacterial Coinfection in Patients With COVID-19 and Influenza Who Are Receiving Extracorporeal Membrane Oxygenation.

Background: Fever and leukocytosis are 2 parameters commonly cited in clinical practice as indications to perform an infectious workup in patients receiving extracorporeal membrane oxygenation (ECMO), but their utility is unknown. Methods: All patients who received ECMO between December 2014 and December 2020 with influenza or COVID-19 were included in this retrospective cohort study. Cultures were included if they were drawn from patients without signs of decompensation. Maximum temperature and white blood cell count were recorded on the day of culture collection. Workups with infections were compared with those that were negative. Results: Of the 137 infectious workups in this 45-patient cohort, 86 (63%) were performed in patients with no signs of decompensation, totaling 165 cultures. These workups yielded 10 (12%) true infections. There were no differences in median (IQR) temperature (100.4 °F [100.2-100.8] vs 100.4 °F [99.3-100.9], P = .90) or white blood cell count (18.6 cells/mL [16.8-20.1] vs 16.7 cells/mL [12.8-22.3], P = .90) between those with and without infections. Conclusions: In patients with influenza or COVID-19 who require ECMO, fever and leukocytosis were common indications for infectious workups, yet results were frequently negative. Despite their use in clinical practice, fever and leukocytosis are not reliable indicators of infection in patients who are hemodynamically stable and receiving ECMO.

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.

Tube Thoracostomy Complications in Patients With ARDS Requiring ECMO: Worse in COVID-19 Patients?

INTRODUCTION: The incidence and management outcomes of COVID-19 patients with acute respiratory distress syndrome (ARDS) on veno-venous extracorporeal membrane oxygenation (V-V ECMO) requiring chest tubes are not well-described. This study sought to explore differences in tube thoracostomy rates and subsequent complications between patients with and without COVID-19 ARDS on V-V ECMO. MATERIALS AND METHODS: This study is a single institution, retrospective cohort study of patients with COVID-19 ARDS requiring V-V ECMO. The control cohort consisted of patients who required V-V ECMO for ARDS-related diagnoses from January 2018 to January 2021. The primary outcome was any complication following initial tube thoracostomy placement. Study approval was obtained from the Brooke Army Medical Center Institutional Review Board (C.2017.152d). RESULTS: Twenty-five COVID-19 patients and 38 controls were included. Demographic parameters did not differ between the groups. The incidence of pneumothorax was not significantly different between the two groups (44% COVID-19 vs. 22% control, OR 2.8, 95% CI 0.95-7.9, P = 0.09). Patients with COVID-19 were as likely to receive tube thoracostomy as controls (36% vs. 24%, OR 1.8, 95% CI 0.55-5.7). Complications, however, were more likely to occur in the COVID-19 group (89% vs. 33%, OR 16, 95% CI, 1.6-201, P = 0.0498). CONCLUSIONS: Tube thoracostomy placement in COVID-19 patients with ARDS requiring V-V ECMO is common, as are complications following initial placement. Clinicians should anticipate the need for re-intervention in this patient population. Small-bore (14Fr and smaller) pigtail catheters appeared to be safe and efficacious in this setting, but further study on tube thoracostomy management in ECMO patients is needed.

Treatment and outcome of gram-positive bacteremia in patients receiving extracorporeal membrane oxygenation.

BACKGROUND: While guidance exists for management of blood stream infections with various invasive devices, there are currently limited data to guide antibiotic selection and duration for bacteremia in patients receiving extracorporeal membrane oxygenation (ECMO). OBJECTIVE: To evaluate the treatment and outcomes of thirty-six patients with Staphylococcus aureus and Enterococcus bacteremia on ECMO support. METHODS: Blood culture data was retrospectively analyzed from patients with Staphylococcus aureus bacteremia (SAB) or Enterococcus bacteremia who underwent ECMO support between March 2012 and September 2021 at Brooke Army Medical Center. RESULTS: Of the 282 patients who received ECMO during this study period, there 25 (9%) patients developed Enterococcus bacteremia and 16 (6%) developed SAB. SAB occurred earlier in ECMO as compared to Enterococcus (median day 2 IQR (1-5) vs. 22 (12-51), p = 0.01). The most common duration of antibiotics was 28 days after clearance for SAB and 14 days after clearance for Enterococcus. 2 (5%) patients underwent cannula exchange with primary bacteremia, and 7 (17%) underwent circuit exchange. 1/3 (33%) patients with SAB and 3/10 (30%) patients with Enterococcus bacteremia who remained cannulated after completion of antibiotics had a second episode of SAB or Enterococcus bacteremia. CONCLUSION: This single center case series is the first to describe the specific treatment and outcomes of patients receiving ECMO complicated by SAB and Enterococcus bacteremia. For patients who remain on ECMO after completion of antibiotics, there is a risk of a second episode of Enterococcus bacteremia or SAB.

Outcomes of Fungemia in Patients Receiving Extracorporeal Membrane Oxygenation.

There are limited data on the treatment of fungal infections complicating extracorporeal membrane oxygenation (ECMO). In 14 patients who developed fungal bloodstream infections on ECMO, 8 (57%) survived to discharge. Of the 5 patients completing treatment prior to decannulation, 2 (40%) developed recurrent fungal infections.

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.

Percutaneous Pulmonary Artery Cannulation to Treat Acute Secondary Right Heart Failure While on Veno-venous Extracorporeal Membrane Oxygenation.

Right heart failure (RHF) is a common, yet difficult to manage, complication of severe acute respiratory distress syndrome requiring extracorporeal membrane oxygenation (ECMO) that is associated with increased mortality. Reports of the use of percutaneous mechanical circulatory support devices for concurrent right heart and respiratory failure are limited. This series describes the percutaneous cannulation of the pulmonary artery for conversion from veno-venous to veno-pulmonary artery return ECMO in 21 patients who developed secondary RHF. All patients cannulated between May 2019 and September 2021 were included. Either a 19 or 21 French venous cannula was placed percutaneously into the pulmonary artery via the internal jugular or subclavian vein, providing a total of 821 days of support (median 23 [4-71] days per patient) with flows up to 6 L/min. Five patients underwent cannulation at the bedside, with the remainder performed in the cardiac catheterization laboratory. Pulmonary artery cannulation occurred after 12 [8.5-23.5] days of ECMO support. Vasoactive infusion requirements decreased significantly within 24 hours of pulmonary artery cannula placement (p = 0.0004). Nonetheless, 75% of these patients expired after a median of 12 [4-63] days of support, with three patients found to have had significant pericardial effusions peri-arrest. This cannulation technique may be an effective alternative to veno-arterial ECMO cannulation or the placement of a dual-lumen cannula for the treatment of RHF.

Critical Care Education and Skills Validation Course for Internal Medicine Physicians in the Military.

INTRODUCTION: Military internist and internal medicine (IM) subspecialist physicians must be prepared to function in both traditional inpatient and outpatient settings, as well as manage critically ill patients within a deployed austere environment. As many critical care procedures are not performed on a routine basis in general IM practice, many active duty IM physicians experience skills degradation and lack confidence in performing these procedures. In order to address this perceived deficiency, the U.S. Army and Air Force Internal Medicine Education and Skills Validation Course was developed to provide essential training in critical care procedures for active duty military IM physicians and subspecialists. MATERIALS AND METHODS: Staff internist and subspecialist physicians at multiple military treatment facilities participated in a 2-day simulation-based training course in critical care procedures included in the Army Individual Critical Task Lists and the Air Force Comprehensive Medical Readiness Program. Educational content included high-yield didactic lectures, multi-disciplinary Advanced Cardiac Life Support/Advanced Trauma Life Support high-fidelity simulation scenarios, and competency training/validation in various bedside procedures, including central venous and arterial line placement, trauma-focused ultrasound exam, airway management and endotracheal intubation, chest tube thoracotomy, and mechanical ventilation, among others. RESULTS: A total of 87 staff IM physicians participated in the course with an average of 2-4 years of experience following completion of graduate medical education. Upon course completion, all participants successfully achieved rigorous, checklist-based, standardized validation in all the required procedures. Survey data indicated a significant improvement in overall skills confidence, with 100% of participants indicating improvement in their ability to function independently as deployed medical officers. CONCLUSIONS: Broad implementation of this program at military hospitals would improve pre-deployment critical care procedural readiness in military IM physicians.

Argatroban for Anticoagulation in Patients Requiring Venovenous Extracorporeal Membrane Oxygenation in Coronavirus Disease 2019.

A significant proportion of patients with coronavirus disease 2019 requiring venovenous extracorporeal membrane oxygenation at our institution demonstrated heparin resistance, which in combination with a heparin shortage resulted in the transition to argatroban with or without aspirin as an alternative anticoagulation strategy. The optimal anticoagulation strategy for coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation is unknown, and therefore, we sought to evaluate the efficacy and safety of argatroban with or without aspirin as an alternative anticoagulation strategy in this patient population. DESIGN: Retrospective cohort. SETTING: Single-center tertiary-care facility in Fort Sam Houston, TX, from 2020 to 2021. PATIENTS: Twenty-four patients who were cannulated for venovenous extracorporeal membrane oxygenation due to respiratory failure secondary to coronavirus disease 2019. INTERVENTIONS: Argatroban, with or without aspirin, was substituted for heparin in coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS: Eighty percent of our coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation demonstrated heparin resistance, and patients who were initially started on heparin were significantly more likely to require a change to argatroban than vice versa due to difficulty achieving or maintaining therapeutic anticoagulation goals (93.4% vs 11.1%; p < 0.0001). The time to reach the therapeutic anticoagulation goal was significantly longer for patients who were initially started on heparin in comparison with argatroban (24 vs 6 hr; p = 0.0173). Bleeding and thrombotic complications were not significantly different between the two cohorts. CONCLUSIONS: Argatroban, with or without aspirin, is an effective anticoagulation strategy for patients who require venovenous extracorporeal membrane oxygenation support secondary to coronavirus disease 2019. In comparison with heparin, this anticoagulation strategy was not associated with a significant difference in bleeding or thrombotic complications, and was associated with a significantly decreased time to therapeutic anticoagulation goal, likely as a result of high rates of heparin resistance observed in this patient population.

Thermal ablation for asthma: current status and technique.

Bronchial thermoplasty (BT) is a novel technique used in the treatment of severe asthma. A catheter is advanced through the bronchoscope and directed radiofrequency waves are applied to the segmental bronchi to reduce airway smooth muscle mass. Several randomized clinical trials demonstrate improvement in quality of life and reduction in exacerbation rates after treatment. BT is a safe and cost effective treatment option for severe asthma which is refractory to medical treatment. Further studies are needed in order to better describe the mechanism of action and the asthma subphenotype that was best benefit from this treatment.