The Ventilatory Ratio as a Predictor of Successful Weaning from a Veno-Venous Extracorporeal Membrane Oxygenator.

Background: Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is a critical intervention for patients with severe lung failure, especially acute respiratory distress syndrome (ARDS). The weaning process from ECMO relies largely on expert opinion due to a lack of evidence-based guidelines. The ventilatory ratio (VR), which correlates with dead space and mortality in ARDS, is calculated as [minute ventilation (mL/min) x arterial pCO2 (mmHg)]/[predicted body weight × 100 × 37.5]. Objectives: The aim of this study was to determine whether the VR alone can serve as a reliable predictor of safe or unsafe liberation from VV-ECMO in critically ill patients. Methods: A multicenter retrospective analysis was conducted, involving ARDS patients undergoing VV-ECMO weaning at Massachusetts General Hospital (January 2016 - December 2020) and at the University Hospital Aachen (January 2012-December 2021). Safe liberation was defined as no need for ECMO recannulation within 48 h after decannulation. Clinical parameters were obtained for both centers at the same time point: 30 min after the start of the SGOT (sweep gas off trial). Results: Of the patients studied, 83.3% (70/84) were successfully weaned from VV-ECMO. The VR emerged as a significant predictor of unsafe liberation (OR per unit increase: 0.38; CI: 0.17-0.81; p = 0.01). Patients who could not be safely liberated had longer ICU and hospital stays, with a trend towards higher mortality (38% vs. 13%; p = 0.05). Conclusions: The VR may be a valuable predictor for safe liberation from VV-ECMO in ARDS patients, with higher VR values associated with an elevated risk of unsuccessful weaning and adverse clinical outcomes.

Venovenous Extracorporeal Membrane Oxygenation Candidacy Decision-Making: Lessons and Hypotheses From a Single-Center Observational Analysis.

BACKGROUND: Use of venovenous extracorporeal membrane oxygenation (ECMO) is increasing, but candidacy selection processes are variable and subject to bias. RESEARCH QUESTION: What are the reasons behind venovenous ECMO candidacy decisions, and are decisions made consistently across patients? STUDY DESIGN AND METHODS: Prospective observational study of all patients, admitted or outside hospital referrals, considered for venovenous ECMO at a tertiary referral center. Relevant clinical data and reasons for candidacy determination were cross-referenced with other noncandidates and candidates and were assessed qualitatively. RESULTS: Eighty-one consultations resulted in 44 noncandidates (54%), 29 candidates (36%; nine of whom subsequently underwent cannulation), and eight deferred decisions (10%). Fifteen unique contraindications were identified, variably present across all patients. Five contraindications were invoked as the sole reason to deny ECMO to a patient. In patients with three or more contraindications, additional contraindications were cited even if the severity was relatively minor. All but four contraindications invoked to deny ECMO to a patient were nonprohibitive for at least one other candidate. Contraindications documented in noncandidates were present but not mentioned in 21 other noncandidates (47%). Twenty-six candidates (90%) had at least one contraindication that was prohibitive in a noncandidate, including a contraindication that was the sole reason to deny ECMO. Contraindications were proposed as informing three prognostic domains, through which patterns of inconsistency could be understood better: (1) irreversible underlying pulmonary process, (2) unsurvivable critical illness, and (3) clinical condition too compromised for meaningful recovery. INTERPRETATION: ECMO candidacy decisions are inconsistent. We identified four patterns of inconsistency in our center and propose a three-domain model for understanding and categorizing contraindications, yielding five lessons that may improve candidacy decision processes until further research can guide practice more definitively.

Fatal ampicillin-sulbactam anaphylaxis in a 34-year-old male.

A 34-year-old man receiving his first dose of ampicillin-sulbactam for osteomyelitis in a hospital setting experienced fatal drug-induced anaphylaxis.

Severe Tricuspid Valve Endocarditis: A Tale of 2 Circuits.

A 25-year-old woman with severe tricuspid valve endocarditis and septic pulmonary emboli required VA-ECMO for recurrent hypoxemia-induced cardiac arrest. We present the clinical challenges requiring ECMO circuit reconfiguration and a percutaneous approach for vegetation debulking. (Level of Difficulty: Intermediate.).

How to Turn It Down: The Evidence and Opinions Behind Adult Venoarterial Extracorporeal Membrane Oxygenation Weaning.

Adequate and durable recovery in patients supported with venoarterial (VA) extracorporeal membrane oxygenation (ECMO) can be challenging to predict. Extracorporeal membrane oxygenation weaning is the process by which the ECMO flows are decreased to assess if a patient is ready for decannulation. The optimal strategies for deciding who to wean and how to wean VA ECMO remain undefined. A retrospective literature review was performed to understand the evidence supporting current practices in ECMO weaning and in particular patient selection and methods. Most published work and expert opinions agree that once the underlying process has resolved, the minimum required physiologic parameters for weaning from ECMO include: hemodynamic stability and cardiac pulsatility, adequate lung function to support oxygenation and ventilation, and evidence of recovered end organ function. Echocardiography is universally used to assess cardiac function during the weaning process. Currently, there is no consensus regarding who is eligible to wean or how to wean ECMO in adults. We have reviewed the literature to summarize the evidence and expert opinions behind VA ECMO weaning, and give an example of the protocol used at our center. We believe this protocol optimizes patient selection for weaning and helps to predict successful decannulation.

Veno-venous Extracorporeal Membrane Oxygenation for Respiratory Failure in COVID-19 Patients: Early Experience From a Major Academic Medical Center in North America.

AND BACKGROUND DATA: VV ECMO can be utilized as an advanced therapy in select patients with COVID-19 respiratory failure refractory to traditional critical care management and optimal mechanical ventilation. Anticipating a need for such therapies during the pandemic, our center created a targeted protocol for ECMO therapy in COVID-19 patients that allows us to provide this life-saving therapy to our sickest patients without overburdening already stretched resources or excessively exposing healthcare staff to infection risk. METHODS: As a major regional referral program, we used the framework of our well-established ECMO service-line to outline specific team structures, modified patient eligibility criteria, cannulation strategies, and management protocols for the COVID-19 ECMO program. RESULTS: During the first month of the COVID-19 outbreak in Massachusetts, 6 patients were placed on VV ECMO for refractory hypoxemic respiratory failure. The median (interquartile range) age was 47 years (43-53) with most patients being male (83%) and obese (67%). All cannulations were performed at the bedside in the intensive care unit in patients who had undergone a trial of rescue therapies for acute respiratory distress syndrome including lung protective ventilation, paralysis, prone positioning, and inhaled nitric oxide. At the time of this report, 83% (5/6) of the patients are still alive with 1 death on ECMO, attributed to hemorrhagic stroke. 67% of patients (4/6) have been successfully decannulated, including 2 that have been successfully extubated and one who was discharged from the hospital. The median duration of VV ECMO therapy for patients who have been decannulated is 12 days (4-18 days). CONCLUSIONS: This is 1 the first case series describing VV ECMO outcomes in COVID-19 patients. Our initial data suggest that VV ECMO can be successfully utilized in appropriately selected COVID-19 patients with advanced respiratory failure.

A Focused Transesophageal Echocardiography Protocol for Intraoperative Management During Orthotopic Liver Transplantation.

OBJECTIVE: The value of a simplified, focused intraoperative transesophageal echocardiography (TEE) protocol in patients undergoing liver transplantation (LT) is unknown. We sought to create and assess a 5-view LT TEE examination focused on 5 prespecified common causes of hypotension during LT. DESIGN: Retrospective cohort study. SETTING: Single-center tertiary academic hospital. PARTICIPANTS: All patients undergoing LT with TEE from January 2010 through May 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A 5-view LT TEE protocol adapted from a published rescue TEE protocol was assessed retrospectively in a cohort of 106 patients. The primary outcome was the frequency with which the protocol would have detected a composite of 5 prespecified causes of hypotension if the TEE exam had been limited to those views. To assess potential influence on intraoperative care, management changes associated with TEE images were extracted from the medical record. The prespecified diagnoses occurred 24 times; the LT TEE protocol would have detected 22 of 24 of these (92%, 95% confidence interval [CI]: 74%-98%). Intraoperative management changes occurred in 15 of 16 patients (94%) with 1 of the prespecified TEE findings, compared with 1 of 27 patients (3.7%) with TEE findings outside those diagnoses (p < 0.0001). CONCLUSIONS: In a retrospective cohort study, a simplified LT TEE protocol would have detected 92% of prespecified TEE findings. Management changes occurred in 94% of those patients, while changes rarely occurred in patients with other TEE findings. A focused LT TEE protocol may diagnose critical pathology adequately and guide management during LT when standard monitors are insufficient.