Right ventricular dysfunction and Pre Implantation Vasopressors in Refractory ARDS Supported by VV-ECMO

Predictors and outcomes associated with right ventricular function in patients with acute respiratory distress syndrome treated with Veno-venous extracorporeal membrane oxygenation

INTRODUCTION

Right ventricular dysfunction is associated with mortality in patients with acute respiratory distress syndrome (ARDS) but information in veno-venous extracorporeal membrane oxygenation (ECMO) settings is limited. Study objectives were to examine factors associated with right ventricular (RV) systolic dysfunction (RVSD) and RV dilation in ECMO patients with ARDS, to compare outcomes in those with and without RVSD and RV dilation defined by qualitative and quantitative parameters, and to describe RVSD evolution during ECMO.

METHODS

Retrospective observational study of adult ARDS patients supported with ECMO at a tertiary care hospital.

RESULTS

Of a total of 62 patients, 56% had RVSD and 61% had RV dilation by qualitative assessment. Male gender, COVID-19, hypercarbia, and pneumothorax were associated with RVSD and RV dilation. In-hospital mortality was significantly higher in patients with RV dilation vs. no dilation (42% vs. 17%, p = .05) but comparisons for patients with and without RVSD (37% vs. 26%, respectively) did not reach statistical significance. Findings were similar when RV size and function were quantified by right to left ventricle end-diastolic area ratio and fractional area change (39% vs. 21% and 36% vs. 20% respectively; p = NS). Of 39 patients with multiple echocardiograms, 9 of 18 with initially normal RV function developed RVSD while RV function normalized in 10 of 21 patients who began ECMO with RVSD.

CONCLUSIONS

Study results suggest an association of RV dilation and RVSD with worse outcomes and a dynamic nature of RV function necessitating close monitoring during the ECMO course.

Head-to-toe bedside ultrasound for adult patients on extracorporeal membrane oxygenation

Bedside ultrasound represents a well-suited diagnostic and monitoring tool for patients on extracorporeal membrane oxygenation (ECMO) who may be too unstable for transport to other hospital areas for diagnostic tests. The role of ultrasound, however, starts even before ECMO initiation. Every patient considered for ECMO should have a thorough ultrasonographic assessment of cardiac and valvular function, as well as vascular anatomy without delaying ECMO cannulation. The role of pre-ECMO ultrasound is to confirm the indication for ECMO, identify clinical situations for which ECMO is not indicated, rule out contraindications, and inform the choice of ECMO configuration. During ECMO cannulation, the use of vascular and cardiac ultrasound reduces the risk of complications and ensures adequate cannula positioning. Ultrasound remains key for monitoring during ECMO support and troubleshooting ECMO complications. For instance, ultrasound is helpful in the assessment of drainage insufficiency, hemodynamic instability, biventricular function, persistent hypoxemia, and recirculation on venovenous (VV) ECMO. Lung ultrasound can be used to monitor signs of recovery on VV ECMO. Brain ultrasound provides valuable diagnostic and prognostic information on ECMO. Echocardiography is essential in the assessment of readiness for liberation from venoarterial (VA) ECMO. Lastly, post decannulation ultrasound mainly aims at identifying post decannulation thrombosis and vascular complications. This review will cover the role of head-to-toe ultrasound for the management of adult ECMO patients from decision to initiate ECMO to the post decannulation phase.

Extracorporeal membrane oxygenation in adult patients with sepsis and septic shock: Why, how, when, and for whom

Sepsis and septic shock remain the leading causes of death in intensive care units. Some patients with sepsis fail to respond to routine treatment and rapidly progress to refractory respiratory and circulatory failure, necessitating extracorporeal membrane oxygenation (ECMO). However, the role of ECMO in adult patients with sepsis has not been fully established. According to existing studies, ECMO may be a viable salvage therapy in carefully selected adult patients with sepsis. The choice of venovenous, venoarterial, or hybrid ECMO modes is primarily determined by the patient's oxygenation and hemodynamics (distributive shock with preserved cardiac output, septic cardiomyopathy (left, right, or biventricular heart failure), or right ventricular failure caused by acute respiratory distress syndrome). Veno-venous ECMO can be used in patients with sepsis and severe acute respiratory distress syndrome when conventional mechanical ventilation fails, and early application of veno-arterial ECMO in patients with sepsis-induced refractory cardiogenic shock may be critical in improving their chances of survival. When ECMO is indicated, the choice of an appropriate mode and determination of the optimal timing of initiation and weaning are critical, particularly in an experienced ECMO center. Furthermore, some special issues, such as ECMO flow, anticoagulation, and antibiotic therapy, should be noted during the management of ECMO support.

Cardiac dysfunction in severe pediatric acute respiratory distress syndrome: the right ventricle in search of the right therapy

Severe acute respiratory distress syndrome in children, or PARDS, carries a high risk of morbidity and mortality that is not fully explained by PARDS severity alone. Right ventricular (RV) dysfunction can be an insidious and often under-recognized complication of severe PARDS that may contribute to its untoward outcomes. Indeed, recent evidence suggest significantly worse outcomes in children who develop RV failure in their course of PARDS. However, in this narrative review, we highlight the dearth of evidence regarding the incidence of and risk factors for PARDS-associated RV dysfunction. While we wish to draw attention to the absence of available evidence that would inform recommendations around surveillance and treatment of RV dysfunction during severe PARDS, we leverage available evidence to glean insights into potentially helpful surveillance strategies and therapeutic approaches.

Right ventricular dysfunction in patients with acute respiratory distress syndrome receiving venovenous extracorporeal membrane oxygenation

Acute respiratory distress syndrome is characterized by non-cardiogenic pulmonary edema, decreased pulmonary compliance, and abnormalities in gas exchange, especially hypoxemia. Patients with acute respiratory distress syndrome (ARDS) who receive support with venovenous (V-V) extracorporeal membrane oxygenation (ECMO) usually have severe lung disease. Many patients with ARDS have associated pulmonary vascular injury which can result in elevated pulmonary vascular resistance and right heart dysfunction. Since V-V ECMO relies upon preserved cardiac function, right heart failure has important implications for patient evaluation, management, and outcomes. Worsening right heart function complicates ARDS and disease processes. Given the increasing use of ECMO to support patients with ARDS, an understanding of right ventricular-ECMO and cardiopulmonary interactions is essential for the clinician. A narrative review of the manifestations of right heart dysfunction, as well as diagnosis and management strategies for the patient with ARDS on ECMO, is provided.

Right Ventricular Function in Acute Respiratory Distress Syndrome: Impact on Outcome, Respiratory Strategy and Use of Veno-Venous Extracorporeal Membrane Oxygenation

Acute respiratory distress syndrome (ARDS) is characterized by protein-rich alveolar edema, reduced lung compliance and severe hypoxemia. Despite some evidence of improvements in mortality over recent decades, ARDS remains a major public health problem with 30% 28-day mortality in recent cohorts. Pulmonary vascular dysfunction is one of the pivot points of the pathophysiology of ARDS, resulting in a certain degree of pulmonary hypertension, higher levels of which are associated with morbidity and mortality. Pulmonary hypertension develops as a result of endothelial dysfunction, pulmonary vascular occlusion, increased vascular tone, extrinsic vessel occlusion, and vascular remodeling. This increase in right ventricular (RV) afterload causes uncoupling between the pulmonary circulation and RV function. Without any contractile reserve, the right ventricle has no adaptive reserve mechanism other than dilatation, which is responsible for left ventricular compression, leading to circulatory failure and worsening of oxygen delivery. This state, also called severe acute cor pulmonale (ACP), is responsible for excess mortality. Strategies designed to protect the pulmonary circulation and the right ventricle in ARDS should be the cornerstones of the care and support of patients with the severest disease, in order to improve prognosis, pending stronger evidence. Acute cor pulmonale is associated with higher driving pressure (≥18 cmH₂O), hypercapnia (PaCO₂ ≥ 48 mmHg), and hypoxemia (PaO₂/FiO₂ < 150 mmHg). RV protection should focus on these three preventable factors identified in the last decade. Prone positioning, the setting of positive end-expiratory pressure, and inhaled nitric oxide (INO) can also unload the right ventricle, restore better coupling between the right ventricle and the pulmonary circulation, and correct circulatory failure. When all these strategies are insufficient, extracorporeal membrane oxygenation (ECMO), which improves decarboxylation and oxygenation and enables ultra-protective ventilation by decreasing driving pressure, should be discussed in seeking better control of RV afterload. This review reports the pathophysiology of pulmonary hypertension in ARDS, describes right heart function, and proposes an RV protective approach, ranging from ventilatory settings and prone positioning to INO and selection of patients potentially eligible for veno-venous extracorporeal membrane oxygenation (VV ECMO).

Persistent Right Ventricle Dilatation in SARS-CoV-2-Related Acute Respiratory Distress Syndrome on Extracorporeal Membrane Oxygenation Support

Objectives

Venovenous extracorporeal membrane oxygenation (ECMO) support may be considered in experienced centers for patients with acute respiratory distress syndrome (ARDS) due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection refractory to conventional treatment. In ECMO patients, echocardiography has emerged as a clinical tool for implantation and clinical management; but to date, little data are available on COVID-related ARDS patients requiring ECMO. The authors assessed the incidence of right ventricular dilatation and dysfunction (RvDys) in patients with COVID-related ARDS requiring ECMO.

Design

Single-center investigation.

Setting

Intensive care unit (ICU).

Participants

A total of 35 patients with COVID-related ARDS requiring ECMO, consecutively admitted to the ICU (March 1, 2020, to February 28, 2021).

Interventions

Serial echocardiographic examinations. RvDys was defined as RV end-diastolic area/LV end-diastolic area >0.6 and tricuspid annular plane excursion <15 mm.

Measurements and Main Results

The incidence of RvDys was 15/35 (42%). RvDys patients underwent ECMO support after a longer period of mechanical ventilation (p = 0.006) and exhibited a higher mortality rate (p = 0.024) than those without RvDys. In nonsurvivors, RvDys was observed in all patients (n = nine) who died with unfavorable progression of COVID-related ARDS. In survivors, weaned from ECMO, a significant reduction in systolic pulmonary arterial pressures was detectable.

Conclusions

According to the authors’ data, in COVID-related ARDS requiring ECMO support, RvDys is common, associated with increased ICU mortality. Overall, the data underscored the clinical role of echocardiography in COVID-related ARDS supported by venovenous ECMO, because serial echocardiographic assessments (especially focused on RV changes) are able to reflect pulmonary COVID disease severity.

ECMO and Right Ventricular Failure: Review of the Literature

Right ventricular (RV) failure is the inability of the RV to maintain sufficient cardiac output in the setting of adequate preload, due to either intrinsic injury to the RV or increased afterload. Medical treatment of RV failure should include optimizing preload, augmenting contractility with vasopressors and inotropes, and considering inhaled pulmonary vasodilators. However, when medical therapies are insufficient, mechanical circulatory support (MCS) is needed to maintain systemic and RV perfusion. The data on MCS for isolated RV failure are limited, but extracorporeal membrane oxygenation (ECMO) appears to be the most efficient and effective modality. For patients with isolated RV failure from acute hypoxemic respiratory failure, veno-venous (VV) ECMO is an appropriate initial configuration, even if the patient is in shock. With primary RV injury or RV failure with concomitant left ventricle (LV) failure, however, venoarterial (VA) ECMO is indicated. Both modalities provide indirect support to the RV by reducing preload, reducing RV wall tension, and delivering oxygenated blood to the coronary circulation. Peripheral cannulation is required in VV-ECMO and is most commonly used in VA-ECMO, allowing for rapid cannulation even in emergencies. Changes in pulsatility on an arterial catheter waveform can indicate changes in clinical status including changes in myocardial function, inadequate preload, worsening RV failure, and excessive VA-ECMO support leading to an elevated LV afterload. Myocardial function may be improved by titration of inotropes or vasodilators, utilization of an Impella or an intra-aortic balloon counterpulsation support devices, or by changes in VA-ECMO support.

Extracorporeal Membrane Oxygenation in Transport Part 1: Extracorporeal Membrane Oxygenation Configurations and Physiology

Extracorporeal membrane oxygenation (ECMO), a term used to describe oxygenation that occurs outside of the body, is an increasingly common means of supporting the most critically ill patients. Because of the invasiveness and high probability of serious complications during ECMO, ECMO is typically indicated only when there is a high likelihood of death with conventional treatment. With continued improvements in technology and increasing clinical experience, transport clinicians are increasingly likely to be called on to transport patients on ECMO. ECMO can be initiated in 2 distinct forms, venovenous or venoarterial, and can primarily support the respiratory system or the cardiac and respiratory systems concurrently. This review will cover the basic physiology and components of ECMO as well as the preparation for ECMO transport for adults.