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.

Outcomes of patients with respiratory failure declined for extracorporeal membrane oxygenation: a prospective observational study.

PURPOSE: Descriptive information on referral patterns and short-term outcomes of patients with respiratory failure declined for extracorporeal membrane oxygenation (ECMO) is lacking. METHODS: We conducted a prospective single-centre observational cohort study of ECMO referrals to Toronto General Hospital (receiving hospital) for severe respiratory failure (COVID-19 and non-COVID-19), between 1 December 2019 and 30 November 2020. Data related to the referral, the referral decision, and reasons for refusal were collected. Reasons for refusal were grouped into three mutually exclusive categories selected a priori: "too sick now," "too sick before," and "not sick enough." In declined referrals, referring physicians were surveyed to collect patient outcome on day 7 after the referral. The primary study endpoints were referral outcome (accepted/declined) and patient outcome (alive/deceased). RESULTS: A total of 193 referrals were included; 73% were declined for transfer. Referral outcome was influenced by age (odds ratio [OR], 0.97; 95% confidence interval [CI], 0.95 to 0.96; P < 0.01) and involvement of other members of the ECMO team in the discussion (OR, 4.42; 95% CI, 1.28 to 15.2; P < 0.01). Patient outcomes were missing in 46 (24%) referrals (inability to locate the referring physician or the referring physician being unable to recall the outcome). Using available data (95 declined and 52 accepted referrals; n = 147), survival to day 7 was 49% for declined referrals (35% for patients deemed "too sick now," 53% for "too sick before," 100% for "not sick enough," and 50% for reason for refusal not reported) and 98% for transferred patients. Sensitivity analysis setting missing outcomes to directional extreme values retained robustness of survival probabilities. CONCLUSION: Nearly half of the patients declined for ECMO consideration were alive on day 7. More information on patient trajectory and long-term outcomes in declined referrals is needed to refine selection criteria.

RéSUMé: OBJECTIF: On manque d'informations descriptives sur les schémas de références et les devenirs à court terme des patient·es atteint·es d'insuffisance respiratoire n'ayant pas pu recevoir une oxygénation par membrane extracorporelle (ECMO). MéTHODE: Nous avons réalisé une étude de cohorte observationnelle prospective monocentrique sur les références vers l'ECMO à l'Hôpital général de Toronto (hôpital d'accueil) pour insuffisance respiratoire grave (COVID-19 et non-COVID-19), entre le 1er décembre 2019 et le 30 novembre 2020. Les données relatives à la référence, à la décision de référence et aux motifs du refus ont été recueillies. Les motifs de refus ont été regroupés en trois catégories mutuellement exclusives sélectionnées a priori : « Trop malade maintenant ¼, « Trop malade avant ¼ et « Pas assez malade ¼. En ce qui concerne les références refusées, un sondage envoyé aux médecins traitant·es avait pour objectif de recueillir les devenirs des patient·es le jour 7 suivant la référence. Les critères d'évaluation principaux de l'étude étaient le résultat de la référence (accepté/refusé) et le devenir des patient·es (vivant·e/décédé·e). RéSULTATS: Au total, 193 références ont été incluses; le transfert a été refusé dans 73 % des cas. L'acceptation ou le refus de la référence était influencé par l'âge (rapport de cotes [RC], 0,97; intervalle de confiance [IC] à 95 %, 0,95 à 0,96; P < 0,01) et la participation d'autres membres de l'équipe ECMO à la discussion (RC, 4,42; IC 95 %, 1,28 à 15,2; P < 0,01). Les devenirs des patient·es étaient manquants pour 46 (24 %) des personnes référées (incapacité de localiser les médecins traitant·es ou incapacité des médecins de se souvenir du devenir). À l'aide des données disponibles (95 références refusées et 52 références acceptées; n = 147), la survie jusqu'au jour 7 était de 49 % pour les références refusées (35 % pour la patientèle jugée « trop malade maintenant ¼, 53 % pour celle « trop malade avant ¼, 100 % pour celle « pas assez malade ¼ et 50 % pour les cas où la raison du refus n'était pas déclarée) et 98 % pour les patient·es transféré·es. L'analyse de sensibilité établissant les résultats manquants à des valeurs extrêmes directionnelles a conservé la robustesse des probabilités de survie. CONCLUSION: Près de la moitié des patient·es pour lesquel·les un traitement sous ECMO a été refusé étaient en vie au jour 7. Davantage d'informations concernant la trajectoire et les devenirs à long terme des patient·es refusé·es sont nécessaires pour parfaire les critères de sélection.

Liberation From Venovenous Extracorporeal Membrane Oxygenation for Respiratory Failure: A Scoping Review.

BACKGROUND: Safe and timely liberation from venovenous extracorporeal membrane oxygenation (ECMO) would be expected to reduce the duration of ECMO, the risk of complications, and costs. However, how to liberate patients from venovenous ECMO effectively remains understudied. RESEARCH QUESTION: What is the current state of the evidence on liberation from venovenous ECMO? STUDY DESIGN AND METHODS: We systematically searched for relevant publications on liberation from venovenous ECMO in Medline and EMBASE. Citations were included if the manuscripts provided any of the following: criteria for readiness for liberation, a liberation protocol, or a definition of successful decannulation or decannulation failure. We included randomized trials, observational trials, narrative reviews, guidelines, editorials, and commentaries. We excluded single case reports and citations where the full text was unavailable. RESULTS: We screened 1,467 citations to identify 39 key publications on liberation from venovenous ECMO. We then summarized the data into five main topics: current strategies used for liberation, criteria used to define readiness for liberation, conducting liberation trials, criteria used to proceed with decannulation, and parameters used to predict decannulation outcomes. INTERPRETATION: Practices on liberation from venovenous ECMO are heterogeneous and are influenced strongly by clinician preference. Additional research on liberation thresholds is needed to define optimal liberation strategies and to close existing knowledge gaps in essential topics on liberation from venovenous ECMO.

Complications Associated With Venovenous Extracorporeal Membrane Oxygenation-What Can Go Wrong?

OBJECTIVES: Despite increasing use and promising outcomes, venovenous extracorporeal membrane oxygenation (V-V ECMO) introduces the risk of a number of complications across the spectrum of ECMO care. This narrative review describes the variety of short- and long-term complications that can occur during treatment with ECMO and how patient selection and management decisions may influence the risk of these complications. DATA SOURCES: English language articles were identified in PubMed using phrases related to V-V ECMO, acute respiratory distress syndrome, severe respiratory failure, and complications. STUDY SELECTION: Original research, review articles, commentaries, and published guidelines from the Extracorporeal Life support Organization were considered. DATA EXTRACTION: Data from relevant literature were identified, reviewed, and integrated into a concise narrative review. DATA SYNTHESIS: Selecting patients for V-V ECMO exposes the patient to a number of complications. Adequate knowledge of these risks is needed to weigh them against the anticipated benefit of treatment. Timing of ECMO initiation and transfer to centers capable of providing ECMO affect patient outcomes. Choosing a configuration that insufficiently addresses the patient's physiologic deficit leads to consequences of inadequate physiologic support. Suboptimal mechanical ventilator management during ECMO may lead to worsening lung injury, delayed lung recovery, or ventilator-associated pneumonia. Premature decannulation from ECMO as lungs recover can lead to clinical worsening, and delayed decannulation can prolong exposure to complications unnecessarily. Short-term complications include bleeding, thrombosis, and hemolysis, renal and neurologic injury, concomitant infections, and technical and mechanical problems. Long-term complications reflect the physical, functional, and neurologic sequelae of critical illness. ECMO can introduce ethical and emotional challenges, particularly when bridging strategies fail. CONCLUSIONS: V-V ECMO is associated with a number of complications. ECMO selection, timing of initiation, and management decisions impact the presence and severity of these potential harms.

Management of the Critically Ill Patient with Pulmonary Arterial Hypertension and Right Heart Failure.

Right ventricular (RV) failure is a recognized complication of pulmonary hypertension (PH). Pregnancy and surgery represent unique challenges to the patient with PH and require input from an interprofessional team. Approach to treatment must embrace sound physiologic principles that are based on optimization of RV preload, contractility, and afterload to improve cardiac function and tissue perfusion before the onset of multiorgan dysfunction. Failure of medical therapy needs to be recognized before the onset of irreversible shock. When appropriate, eligible patients should be considered for mechanical circulatory support as a bridge to recovery or transplantation.

When is tamponade not an echocardiographic diagnosis Or is it ever?

Although cardiac tamponade remains a clinical diagnosis, echocardiography is an essential tool to detect fluid in the pericardial space. Interpretation of echocardiographic findings and assessment of physiologic and hemodynamic consequences of a pericardial effusion require a thorough understanding of pathophysiologic processes. Certain echocardiographic signs point toward the presence of cardiac tamponade: a dilated inferior vena cava (IVC), collapse of the cardiac chambers, an inspiratory bulge of the interventricular septum into the left ventricle (LV) (the "septal bounce"), and characteristic respiratory variations of Doppler flow velocity recordings. However, in certain circumstances (e.g., mechanical ventilation, post-surgical patients, and pulmonary hypertension), these echocardiographic signs can be missing, despite the presence of clinical tamponade. Failure to recognize a potentially life-threatening clinical condition due to the absence of corresponding echocardiographic findings can delay both diagnosis and life-saving treatment. Thus, in the context of critical care, echocardiography should only be used to confirm the presence of pericardial fluid or localized hematoma, and the diagnosis of tamponade should rely on clinical criteria.

Monitoring during extracorporeal membrane oxygenation.

PURPOSE OF REVIEW: Extracorporeal membrane oxygenation (ECMO) offers advanced mechanical support to patients with severe acute respiratory and/or cardiac failure. Ensuring an adequate therapeutic approach as well as prevention of ECMO-associated complications, by means of timely liberation, forms an essential part of standard ECMO care and is only achievable through continuous monitoring and evaluation. This review focus on the cardiorespiratory monitoring tools that can be used to assess and titrate adequacy of ECMO therapy; as well as methods to assess readiness to wean and/or discontinue ECMO support. RECENT FINDINGS: Surrogates of tissue perfusion and near infrared spectroscopy are not standards of care but may provide useful information in select patients. Echocardiography allows to determine cannulas position, evaluate cardiac structures, and function, and diagnose complications. Respiratory monitoring is mandatory to achieve lung protective ventilation and identify early lung recovery, surrogate measurements of respiratory effort and ECMO derived parameters are invaluable in optimally managing ECMO patients. SUMMARY: Novel applications of existing monitoring modalities alongside evolving technological advances enable the advanced monitoring required for safe delivery of ECMO. Liberation trials are necessary to minimize time sensitive ECMO related complications; however, these have yet to be standardized.

How I Select Which Patients With ARDS Should Be Treated With Venovenous Extracorporeal Membrane Oxygenation.

ARDS is a lethal form of acute respiratory failure, and because no specific treatments exist, supportive care remains the primary management strategy in these patients. Extracorporeal membrane oxygenation (ECMO) has emerged as an intervention in patients with severe ARDS to facilitate gas exchange and the delivery of more lung protective ventilation. Over the past 20 years, improvements in ECMO technology have increased its safety and transportability, making it far more available to this patient population globally. Deciding which patients with ARDS should be initiated on ECMO remains a challenging question. Numerous clinical and laboratory markers have been investigated, and multiple risk scores developed, to aid physicians in this decision-making process. However, they are still imperfect, and the choice is often based on institutional guidelines and the clinical impression of the treating physician. Given the potential risks and resource implications for this intervention, patient selection is critical and it is important to provide ECMO only to patients who have a reasonable chance for recovery or bridge to transplantation. In patients undergoing ECMO where there is no potential for recovery or transplant, the only option may be withdrawal of ECMO and palliation. These patients may be awake and interactive, which is often a very challenging scenario for patients, families, and the clinical team. In this article, we present a more controversial case and a review of the literature regarding the selection of patients with ARDS who should receive ECMO.

Modelos de reanimación en la terapia intensiva y desarrollo de complicaciones en el postoperatorio de trasplante hepático / Resuscitation models for liver transplantation at the intensive care unit and the development of postoperatory complications / Modelos de reanimação na terapia intensiva e desenvolvimento das complicações pós-operatórias em transplante hepático

Resumen: El periodo de reanimación después del trasplante hepático ortotópico (THO) es un desafío debido a las alteraciones fisiológicas relacionadas con la enfermedad hepática terminal (EHT). Material y métodos: Este es un estudio retrospectivo que evalúa las primeras 48 horas de manejo en la unidad de cuidados intensivos (UCI) de un hospital de la Ciudad de México. Los pacientes se clasificaron en 4 grupos según la dosis de norepinefrina (NADR) utilizada y el balance neto de líquidos (BalT): Grupo 1 norepinefrina menos de 0.1 μg/1 kg/min/BalT 3,805 ml, grupo 2 norepinefrina mayor de 0.1 μg/kg/min/BalT menos de 3,805 ml, grupo 3 norepinefrina menos de 0.1 μg/kg/min/BalT mayor de 3,805 ml, grupo 4 norepinefrina mayor de 0.1 μg/kg/min/BalT mayor de 3,805 ml. Se evaluó el desarrollo de complicaciones Post-THO. Las variables principales de valoración fueron; complicaciones médicas generales, reoperación quirúrgica y duración de estancia en el hospital (DEH), duración de la ventilación mecánica, lesión renal aguda, función anormal del injerto y cultivos positivos. Resultados: 36.6% de los pacientes pertenecían al grupo 1, 18.8% al grupo 2, 17.8% al grupo 3 y 26.7% al grupo 4. La duración de la estancia fue de 3.39 días, tiempo medio de ventilación mecánica de 16.5 horas. El 67% desarrolló complicaciones médicas, el 15.8% de reoperación quirúrgica, el 62% de lesión renal aguda, el 50.5% de función anormal del injerto y el 45.5% de cultivos perioperatorios positivos. La duración de la estancia fue de 3.39 días, tiempo medio de ventilación mecánica de 16.5 horas. De estos criterios de valoración primarios, sólo la duración de la estancia y la duración de la ventilación mecánica fueron diferentes entre los grupos. Conclusiones: La duración de la estancia y la necesidad de ventilación mecánica, fueron diferentes entre los grupos. El desarrollo de otros criterios de valoración primarios fue independiente del modelo de resucitación.

Abstract: The resuscitation period after orthotopic liver transplantation (OLT) is challenging due to the physiological alterations related to end stage liver disease (ESLD). Material and methods: This is a retrospective study assessing the first 48 hours management at the intensive care unit (ICU) of at hospital in México City. Patients were categorized into 4 groups according to norepinephrine (NADR) dose used and net fluid balance (BalT): group 1 norepinephrine < 0.1 μg/1 kg/min/BalT 3,805 mL, group 2 norepinephrine > 0.1 μg/kg/min/BalT < 3,805 mL, group 3 norepinephrine < 0.1 μg/kg/min/BalT > 3,805 mL, group 4 norepinephrine > 0.1 μg/kg/min/BalT > 3,805 mL. The relationship with the development of Po-OLT complications was assessed. Primary endpoints were general medical complications, surgical reoperation, and length of stay (LOS), length of mechanical ventilation, acute kidney injury, abnormal graft function and positive cultures. Results: 36.6% of the patients belonged to group 1, 18.8% to group 2, 17.8% to group 3, and 26.7% to group 4. The length of stay was 3.39 days, mean time of mechanical ventilation of 16.5 hours. 67% developed medical complications, 15.8% surgical reoperation, 62% acute kidney injury, 50.5% abnormal graft function and 45.5% positive perioperative cultures. Of these primary endpoints, only length of stay and length of mechanical ventilation were different among groups. Conclusions: Length of stay and mechanical ventilation need was different among groups. Development of other primary endpoints was independent of the resuscitation model.

Resumo: O período de reanimação no pós-operatório de transplante hepático ortotópico (THO) é um desafio devido a alterações fisiológicas relacionados com a doença hepática terminal (DHT). Material e métodos: Realizou-se um estudo retrospectivo que avaliou as primeiras 48 horas do THO na unidade de terapia intensiva (UTI) de um hospital na Cidade do México. Os pacientes foram classificados em 4 grupos de acordo com a dose de norepinefrina (NADR) utilizada e o balaço hidrico (BalT): grupo 1 norepinefrina menor de 0.1 μg/1 kg/min/BalT menor de 3.805 ml, grupo 2 norepinefrina maior de 0.1 μg/kg/min/BalT menor de 3.805 ml, grupo 3 norepinefrina menor de 0.1 μg/kg/min/BalT maior de 3.805 ml, grupo 4 norepinefrina maior de 0.1 μg/kg /min/BalT maior de 3.805 ml. Analizou-se a relação que existe com o desenvolvimento de complicações Post-THO. As principais variáveis da avaliação foram: complicações médicas, reintervenção cirúrgica e tempo de permanência hospitalária, duração da ventilação mecânica, lesão renal aguda, função anormal do enxerto e cultivos positivos. Resultados: 36.6% dos pacientes pertenciam ao grupo 1, 18.8% ao grupo 2, 17.8% para o grupo 3 e 26.7% ao grupo 4. O tempo de permanência hospitalar foi 3.39 dias, ventilação mecânica de 16.5 horas tempo médio. 67% desenvolveram complicações médicas, 15.8% reintervenção cirúrgica, 62% de lesão renal aguda, 50.5% função anormal do enxerto e 45.5% de cultivos pré-operatórios positivos. Destes parâmetros, o TEUTI e TVM apresentaram diferenças entre os modelos de reanimação. Conclusão: O TEUTI e TVM variaram de acordo ao modelo de reanimação. Os outros resultados primários foram independentes ao modelo de reanimação.