Histopathologic Findings in Lungs of Patients Treated With Extracorporeal Membrane Oxygenation

Autoptic Findings in Patients Treated with (VA-ECMO) after Cardiac Arrest

Background: This study examines the results of autopsy examinations specifically aimed at documenting complications arising from the implantation phase and treatment with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in patients with refractory cardiac arrest. ECMO and VA-ECMO in particular are life-saving interventions that, in the case of cardiac arrest, can temporarily replace cardiac pump function. VA-ECMO is, however, a very invasive procedure and is associated with early mechanical, haemorrhagic, and thrombotic events, infections, and late multi-organ dysfunction. Aim: This research aims to evaluate autoptic and histologic findings in patients on VA-ECMO support, providing clinical and forensic evaluation elements with respect to the procedure and clinical settings. Materials and Methods: The study analysed 10 cases, considering variables such as the duration of cardiac arrest, understood as the time between the cardiac arrest event and reperfusion with VA-ECMO, the duration of VA-ECMO support, and any complications detected by clinicians during treatment. Results: The results highlighted the presence of numerous ischemic and haemorrhagic events affecting various organs. Among them, the intestines were particularly vulnerable, even after a short ECMO duration. Conclusions: ECMO was found to accelerate post-mortem decomposition, affecting post-mortem interval estimations, and cardiac damage from reperfusion, underlining the need to meticulously select indications for treatment with VA-ECMO and perform constant clinical evaluations during the treatment itself.

Successful management of harlequin syndrome due to pulmonary hemorrhage and atelectasis with VAV- ECMO

INTRODUCTION

Pulmonary hemorrhage is a life-threatening complication of VA-ECMO occasionally presenting with Harlequin syndrome.

CASE REPORT

We present a case of a VA-ECMO patient complicated with pulmonary hemorrhage, complete right lung atelectasis and differential hypoxia refractory to conventional treatment including optimal mechanical ventilation and bronchoscopy interventions. Patient was successfully managed by conversion of VA to VAV-ECMO.

DISCUSSION

Pulmonary hemorrhage and atelectasis treatment in a VA-ECMO patient includes transfusion, hold and reversal of anticoagulation, bronchoscopy interventions and optimization of VA-ECMO and ventilator support. Differential hypoxia may ensue due to residual native cardiac function. If refractory to conservative treatment, a VAV-ECMO configuration may be utilized to improve upper body oxygenation by inserting an additional cannula to the superior vena cava.

CONCLUSION

VAV-ECMO is an ECMO configuration support in patients at risk of Harlequin syndrome presenting with pulmonary hemorrhage.

Autopsy Histopathologic Lung Findings in Patients Treated With Extracorporeal Membrane Oxygenation

CONTEXT.—

Extracorporeal membrane oxygenation (ECMO) is increasingly used in the treatment of respiratory and cardiac failure, but data describing lung histopathology in ECMO recipients are limited.

OBJECTIVE.—

To examine pulmonary histopathologic findings in patients who underwent venovenous (VV) ECMO for pulmonary reasons or venoarterial (VA) ECMO for cardiac indications shortly before death, and to determine if the pulmonary changes provided insights into therapy that may prevent complications and improve outcome.

DESIGN.—

We conducted a retrospective study of lung autopsies, from VV and VA ECMO recipients and patients with acute respiratory distress syndrome (ARDS) and non-ECMO treatment, between 2008 and 2020 in Silesia Center for Heart Diseases in Zabrze, Poland.

RESULTS.—

Among 83 ECMO patients (42-64 years; men, 57 [68.7%]), the most common histopathologic findings were bronchopneumonia (44 [53.0%]), interstitial edema (40 [48.2%]), diffuse alveolar damage (DAD; 32 [38.6%]), hemorrhagic infarct (28 [33.7%]), and pulmonary hemorrhage (25 [30.1%]). DAD was associated with longer ECMO treatment and longer hospital stay. The use of VV ECMO was a predictor of DAD in patients with ARDS and undergoing ECMO, but it also occurred in 21 of 65 patients (32.3%) in the VA ECMO group, even though VA ECMO was used for heart failure.

CONCLUSIONS.—

Although DAD was significantly more common in lung autopsies of VV ECMO patients, one-third of VA ECMO patients had histopathologic changes characteristic of ARDS. The presence of DAD in lung autopsies of patients treated with VA ECMO indicates that in these patients, protective lung ventilation should be considered.

Nonspecific interstitial pneumonia pattern is a frequent finding in patients with post-acute COVID-19 syndrome treated with bilateral orthotopic lung transplantation: current best evidence

Patients with post-acute COVID-19 (PA-COVID) syndrome or long COVID-19 syndrome develop persistent symptoms and complications that last beyond 4 weeks of the initial infection. There is limited information regarding the pulmonary pathology in PA-COVID patients who require bilateral orthotopic lung transplantation (BOLT). Our experience with 40 lung explants from 20 PA-COVID patients who underwent BOLT is described. Clinicopathologic findings are correlated with best evidence from literature. The lung parenchyma showed bronchiectasis (n = 20) and severe interstitial fibrosis with areas resembling the nonspecific interstitial pneumonia (NSIP) pattern of fibrosis (n = 20), interstitial fibrosis not otherwise specified (n = 20), and fibrotic cysts (n = 9). None of the explants exhibited a usual interstitial pneumonia pattern of fibrosis. Other parenchymal changes included multinucleated giant cells (n = 17), hemosiderosis (n = 16), peribronchiolar metaplasia (n = 19), obliterative bronchiolitis (n = 6), and microscopic honeycombing (n = 5). Vascular abnormalities included thrombosis of a lobar artery (n = 1) and microscopic thrombi in small vessels (n = 7). Systematic literature review identified 7 articles reporting the presence in 12 patients of interstitial fibrosis showing the NSIP pattern (n = 3), organizing pneumonia/diffuse alveolar damage (n = 4) and not otherwise specified (n = 3) patterns. All but one of these studies also reported the presence of multinucleated giant cells and none of the studies reported the presence of severe vascular abnormalities. PA-COVID patients undergoing BOLT show a pattern of fibrosis that resembles a mixed cellular-fibrotic NSIP pattern and generally lack severe vascular complications. As the NSIP pattern of fibrosis is often associated with autoimmune diseases, additional studies are needed to understand the mechanism of disease and learn whether this information can be used for therapeutic purposes.

Pulmonary Protection from Left Ventricular Distension During Venoarterial Extracorporeal Membrane Oxygenation: Review and Management Algorithm

The use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in adults for refractory cardiogenic shock has risen exponentially during the prior decade. Although VA-ECMO provides cardiopulmonary support, it can alter left ventricular (LV) loading conditions leading to LV distension, which makes the lungs susceptible to congestion and promotes intracardiac thrombosis. These conditions can be alleviated by pharmacologic and mechanical unloading, but gaps in knowledge remain on optimal timing and methods of this approach. This review provides an overview of the epidemiology of VA-ECMO, describes pathophysiology and methods for monitoring and reducing LV loading and summarizes contemporary studies examining the association between LV unloading and adverse events. We offer a simple protocol for implementing LV unloading during VA-ECMO to provide pulmonary protection and improve outcomes.

The ABCDE approach to difficult weaning from venoarterial extracorporeal membrane oxygenation

Venoarterial extracorporeal membrane oxygenation (VA ECMO) has been increasingly applied in patients with cardiogenic shock in recent years. Nevertheless, many patients cannot be successfully weaned from VA ECMO support and 1-year mortality remains high. A systematic approach could help to optimize clinical management in favor of weaning by identifying important factors in individual patients. Here, we provide an overview of pivotal factors that potentially prevent successful weaning of VA ECMO. We present this through a rigorous approach following the relatable acronym ABCDE, in order to facilitate widespread use in daily practice.

Late Complications of COVID-19: A Morphologic, Imaging, and Droplet Digital Polymerase Chain Reaction Study of Lung Tissue

CONTEXT

Studies of lungs in patients with COVID-19 have focused on early findings.

OBJECTIVE

To systematically study histopathologic, imaging features and presence of SARSCoV-2 RNA in lung tissue from patients in later stages of COVID-19.

DESIGN

Autopsies, explants, surgical lung biopsies; and transbronchial, cryo, and needle biopsies were studied from patients with COVID-19, whose onset of symptoms/confirmed diagnosis was more than 28 days before the procedure. Available images were reviewed. Reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) for SARS-CoV-2 RNA was performed on lung tissue.

RESULTS

Forty-four specimens (43 patients, median age 59.3 years, 26 [60.5%] male) showed features of acute lung injury (ALI) in 39 (88.6%), predominantly organizing pneumonia (OP) and diffuse alveolar damage (DAD), up to 298 days after onset of COVID-19. Fibrotic changes were found in 33 specimens (75%), most commonly fibrotic DAD (N=22) and cicatricial OP (N=12). Time between acquiring COVID-19 and specimen was shorter in patients with diffuse ALI (median 61.5 days) compared to patients with focal (140 days) or no ALI (130 days) (P=.009). Sixteen (of 20, 80%) SARS-CoV-2 RT-ddPCR tests were positive, up to 174 days after COVID-19 onset. Time between COVID-19 onset and most recent CT in patients with consolidation on imaging was shorter (median 43.0 days) versus patients without consolidation (87.5 days; P=.02). Reticulations were associated with longer time after COVID-19 onset to CT (median 82 days vs 23.5 days, P=.006).

CONCLUSIONS

ALI and SARS-CoV-2 RNA can be detected in patients with COVID-19 for many months. ALI may evolve into fibrotic interstitial lung disease.

Extracorporeal membrane oxygenation in the forensic setting: A series of 19 forensic cases

Extracorporeal membrane oxygenation (ECMO) employs vascular cannulation and a gas exchange circuit to provide support to patients with severely compromised cardiopulmonary function. ECMO is often the last intervention taken before death and thus presents a unique challenge to medical examiners. This study describes the characteristics of decedents on ECMO at the time of death, including clinical indications, types of circuit configurations, causes and manners of death, gross findings at autopsy, and therapeutic complications. Files of a regional medical examiner office within an academic medical center were searched for the period between 2013 and 2019. Nineteen cases were identified with a median age of 36 years. The circumstances surrounding the initial presentation included: sudden death, trauma, substance abuse, homicide, therapeutic complication, work-related injury, drowning, and hypothermia. The underlying causes of death included injury-related, as well as respiratory and cardiac-related natural diseases. The time spent on ECMO varied from less than 1 h to 10 months. Complications encountered due to ECMO included cannulation site bleeding, pneumohemopericardium, retroperitoneal hematoma, limb ischemia, clotting, and cannula dislodgement. The patient population likely to receive ECMO has significant overlap with death circumstances likely to be reported to the medical examiner. As ECMO therapy has become increasingly available, it is of importance for medical examiners and death investigators to be familiar with the procedure as well as its limitations. Familiarity with ECMO and its sequelae allows for the proper documentation of postmortem findings and fosters an informed determination of the cause and manner of death.

Monitoring lung injury with particle flow rate in LPS- and COVID-19-induced ARDS

In severe acute respiratory distress syndrome (ARDS), extracorporeal membrane oxygenation (ECMO) is a life-prolonging treatment, especially among COVID-19 patients. Evaluation of lung injury progression is challenging with current techniques. Diagnostic imaging or invasive diagnostics are risky given the difficulties of intra-hospital transportation, contraindication of biopsies, and the potential for the spread of infections, such as in COVID-19 patients. We have recently shown that particle flow rate (PFR) from exhaled breath could be a noninvasive, early detection method for ARDS during mechanical ventilation. We hypothesized that PFR could also measure the progress of lung injury during ECMO treatment. Lipopolysaccharide (LPS) was thus used to induce ARDS in pigs under mechanical ventilation. Eight were connected to ECMO, whereas seven animals were not. In addition, six animals received sham treatment with saline. Four human patients with ECMO and ARDS were also monitored. In the pigs, as lung injury ensued, the PFR dramatically increased and a particular spike followed the establishment of ECMO in the LPS-treated animals. PFR remained elevated in all animals with no signs of lung recovery. In the human patients, in the two that recovered, PFR decreased. In the two whose lung function deteriorated while on ECMO, there was increased PFR with no sign of recovery in lung function. The present results indicate that real-time monitoring of PFR may be a new, complementary approach in the clinic for measurement of the extent of lung injury and recovery over time in ECMO patients with ARDS.

Frequency and Significance of Pathologic Pulmonary Findings in Postmortem Examinations-A Single Center Experience before COVID-19

Coronavirus disease 2019 (COVID-19) has shown the importance of postmortem investigation of deceased patients. For a correct interpretation of the pulmonary findings in this new era, it is, however, crucial to be familiar with pathologic pulmonary conditions observed in postmortem investigations in general. Adequate postmortem histopathological evaluation of the lungs may be affected by suboptimal gross work up, autolysis or poor fixation. Using a standardized preparation approach which consisted in instillation of 4% buffered formaldehyde through the large bronchi for proper fixation and preparing large frontal tissue sections of 1-2 cm thickness after at least 24 h fixation, we comprehensively analyzed postmortem pulmonary findings from consecutive adult autopsies of a two-year period before the occurrence of COVID-19 (2016-2017). In total, significant pathological findings were observed in 97/189 patients (51%), with 28 patients showing more than one pathologic condition. Acute pneumonia was diagnosed 33/128 times (26%), embolism 24 times (19%), primary pulmonary neoplasms 18 times (14%), organizing pneumonia and other fibrosing conditions 14 times (11%), pulmonary metastases 13 times (10%), diffuse alveolar damage 12 times (9%), severe emphysema 9 times (7%) and other pathologies, e.g., amyloidosis 5/128 times (4%). Pulmonary/cardiopulmonary disease was the cause of death in 60 patients (32%). Clinical and pathological diagnoses regarding lung findings correlated completely in 75 patients (40%). Autopsy led to confirmation of a clinically suspected pulmonary diagnosis in 57 patients (39%) and clarification of an unclear clinical lung finding in 16 patients (8%). Major discrepant findings regarding the lungs (N = 31; 16%) comprised cases with clinical suspicions that could not be confirmed or new findings not diagnosed intra vitam. A significant proportion of acute pneumonias (N = 8; 24% of all cases with this diagnosis; p = 0.011) was not diagnosed clinically. We confirmed the frequent occurrence of pulmonary pathologies in autopsies, including inflammatory and neoplastic lesions as the most frequent pathological findings. Acute pneumonia was an important cause for discrepancy between clinical and postmortem diagnostics.

Pulmonary Pathology of COVID-19 Following 8 Weeks to 4 Months of Severe Disease: A Report of Three Cases, Including One With Bilateral Lung Transplantation

OBJECTIVES

Current knowledge of the pulmonary pathology of coronavirus disease 2019 (COVID-19) is based largely on postmortem studies. In most, the interval between disease onset and death is relatively short (<1 month). Information regarding lung pathology in patients who survive for longer periods is scant. We describe the pathology in three patients with severe COVID-19 who underwent antemortem examination of lung tissue at least 8 weeks after initial diagnosis.

METHODS

We conducted a retrospective case series.

RESULTS

The first patient developed acute respiratory failure and was started on extracorporeal membrane oxygenation (ECMO) on day 21, with subsequent hemothorax. Debridement (day 38) showed extensive lung infarction with diffuse alveolar damage and Candida overgrowth. The second patient developed acute respiratory failure requiring mechanical ventilation that did not improve despite ECMO. Surgical lung biopsy on day 74 showed diffuse interstitial fibrosis with focal microscopic honeycomb change. The third patient also required ECMO and underwent bilateral lung transplantation on day 126. The explanted lungs showed diffuse interstitial fibrosis with focal microscopic honeycomb change.

CONCLUSIONS

This series provides histologic confirmation that complications of COVID-19 after 8 weeks to 4 months of severe disease include lung infarction and diffuse interstitial fibrosis.

Pulmonary complications associated with veno-arterial extra-corporeal membrane oxygenation: a comprehensive review

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a life-saving technology that provides transient respiratory and circulatory support for patients with profound cardiogenic shock or refractory cardiac arrest. Among its potential complications, VA-ECMO may adversely affect lung function through various pathophysiological mechanisms. The interaction of blood components with the biomaterials of the extracorporeal membrane elicits a systemic inflammatory response which may increase pulmonary vascular permeability and promote the sequestration of polymorphonuclear neutrophils within the lung parenchyma. Also, VA-ECMO increases the afterload of the left ventricle (LV) through reverse flow within the thoracic aorta, resulting in increased LV filling pressure and pulmonary congestion. Furthermore, VA-ECMO may result in long-standing pulmonary hypoxia, due to partial shunting of the pulmonary circulation and to reduced pulsatile blood flow within the bronchial circulation. Ultimately, these different abnormalities may result in a state of persisting lung inflammation and fibrotic changes with concomitant functional impairment, which may compromise weaning from VA-ECMO and could possibly result in long-term lung dysfunction. This review presents the mechanisms of lung damage and dysfunction under VA-ECMO and discusses potential strategies to prevent and treat such alterations.

Insult to Injury: Development of Alveolar Hemorrhage after Initiation of Extracorporeal Membrane Oxygenation

Background

Extracorporeal membrane oxygenation (ECMO) is associated with complications that are separate from the underlying diagnoses that require its use. One of the foremost complications of ECMO is a high incidence of bleeding, including alveolar hemorrhage (AH), which is believed to be due to both prophylactic anticoagulation and critical illness-induced systemic coagulopathy. However, akin to systemic inflammatory response syndrome after cardiopulmonary bypass, ECMO causes widespread systemic inflammation and acute lung injury, which likely further predisposes patients to AH. The burden of clinically significant AH among patients on ECMO for advanced lung disease remains unknown.

Patients and methods

Charts of patients with advanced lung disease who required ECMO at a single institution were reviewed. The clinical course and variables of patients who developed AH and those who did not were compared.

Results

This report describes five patients who developed AH after initiation of venovenous ECMO for refractory hypoxemia. Clinical and laboratory variables did not predict the development or the prognosis of AH. Two of these patients with refractory hypoxemia and AH were treated with pulse-dose corticosteroids, with a dramatic response in one case.

Conclusion

The acute decompensation of the patients and response to corticosteroids suggest AH was mediated by a systemic inflammatory process, as opposed to coagulopathy alone. Judicious use of steroids may be considered among select patients who develop AH without symptoms of systemic coagulopathy after initiation of ECMO.

How to cite this article

Williams S, Batra K, Mohanka M, Bollineni S, Kaza V, Torres F, et al. Insult to Injury: Development of Alveolar Hemorrhage after Initiation of Extracorporeal Membrane Oxygenation. Indian J Crit Care Med 2020;24(12):1201-1205.