Cerebral Microbleeds and Intracranial Hemorrhages in Adult Patients on Extracorporeal Membrane Oxygenation-Autopsy Study

Association Between Cerebral Microbleeds and Neurological Outcomes in Patients Who Underwent Extracorporeal Membrane Oxygenation

BACKGROUND

Cerebral microbleeds (CMBs) are common and varied in patients receiving extracorporeal membrane oxygenation (ECMO). Here, the authors describe CMB findings in patients receiving ECMO and their association with clinical factors.

METHODS AND RESULTS

A total of 138 patients receiving ECMO were enrolled and categorized as venovenous and venoarterial. Blood coagulation profiles during ECMO support and Glasgow Coma Scale (GCS) scores within 7 days were recorded. Patients with CMBs exhibited prolonged activated clotting time (P<0.001), decreased fibrinogen levels (P<0.001), reduced platelet counts (P<0.001), and extended prothrombin time (P<0.001). A significant correlation (P<0.05) was observed between the presence of CMBs and most coagulation parameters among all patients. Patients with venoarterial ECMO had significantly higher activated partial thromboplastin time, activated clotting time, and prothrombin time compared with those with venovenous ECMO (all P<0.05). Patients with a less severe CMB burden exhibited higher GCS scores and better neurological injury outcomes at both 7 and 90 days. CMB burden in all patients with ECMO was significantly correlated (P<0.05) with most blood coagulation profiles and neurological injury.

CONCLUSIONS

CMB burdens after ECMO are common, varied, and associated with a variety of clinical conditions. These findings may guide ECMO management.

Cerebral Microbleeds in Critically Ill Patients with Respiratory Failure or Sepsis: A Scoping Review

BACKGROUND

Cerebral microbleeds (CMBs) have been described in critically ill patients with respiratory failure, acute respiratory distress syndrome (ARDS), or sepsis. This scoping review aimed to systematically summarize existing literature on critical illness-associated CMBs.

METHODS

Studies reporting on adults admitted to the intensive care unit for respiratory failure, ARDS, or sepsis with evidence of CMBs on magnetic resonance imaging were included for review following a systematic search across five databases (MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and Web of Science) and a two-stage screening process. Studies were excluded if patients' CMBs were clearly explained by another process of neurological injury.

RESULTS

Forty-eight studies reporting on 216 critically ill patients (mean age 57.9, 18.4% female) with CMBs were included. Of 216, 197 (91.2%) patients developed respiratory failure or ARDS, five (2.3%) patients developed sepsis, and 14 (6.5%) patients developed both respiratory failure and sepsis. Of 211 patients with respiratory failure, 160 (75.8%) patients had coronavirus disease 2019. The prevalence of CMBs among critically ill patients with respiratory failure or ARDS was 30.0% (111 of 370 patients in cohort studies). The corpus callosum and juxtacortical area were the most frequently involved sites for CMBs (64.8% and 41.7% of all 216 patients, respectively). Functional outcomes were only reported in 48 patients, among whom 31 (64.6%) were independent at discharge, four (8.3%) were dependent at discharge, and 13 (27.1%) did not survive until discharge. Cognitive outcomes were only reported in 11 of 216 patients (5.1%), all of whom showed cognitive deficits (nine patients with executive dysfunction and two patients with memory deficits).

CONCLUSIONS

Cerebral microbleeds are commonly reported in patients with critical illness due to respiratory failure, ARDS, or sepsis. CMBs had a predilection for the corpus callosum and juxtacortical area, which may be specific to critical illness-associated CMBs. Functional and cognitive outcomes of these lesions are largely unknown.

Critical illness-associated cerebral microbleeds: What we learned after the COVID-19 pandemic. A systematic review

BACKGROUND

Cerebral microbleeds in critically ill patients have been a reported complication of COVID-19. However, they have also been described in patients with other respiratory infections and conditions requiring intensive care unit (ICU) admission. Here, we aim to describe the clinical characteristics of critical illness-associated cerebral microbleeds and compare COVID-19 cases with those related to other conditions.

METHODS

We performed a systematic literature review in PubMed and Embase for Critical Illness-Associated Cerebral Microbleeds to describe the clinical characteristics of this entity, in both COVID-19 and non-COVID-19 patients.

RESULTS

Of 157 manuscripts screened, 23 were included, totalling 143 cases (median age 61, interquartile range [IQR] 54-66), 104 (73 %) men. SARS-CoV2-associated pneumonia was found in 105 (73 %) cases. The median ICU stay was 34 (IQR 26-42) days and the median mechanical ventilation time was 24 (IQR 14-35) days. Cerebral microbleeds were more frequently juxtacortical (79 %) or located in the corpus callosum (75 %) and deep white matter (71 %) for both COVID-19 and non-COVID-19 individuals, whilst brainstem location was more frequent in non-COVID-19 patients (37 % vs 13 %; p = 0.02). Non-COVID-19 patients were younger (median age 42, IQR 30-54 years) than COVID-19 patients (median age 62, IQR 57-67 years; p < 0.001), and the median platelet count was significantly higher (200,000; IQR 116,000-284,000 ng/dL) in COVID-19 patients than non-COVID-19 patients (50,000; IQR 39,000-61,000 ng/mL; (p < 0.001).

CONCLUSIONS

In this systematic review, most patients presented respiratory failure with prolonged mechanical ventilation and ICU stay. Juxtacortical white matter and corpus callosum are characteristic locations of critical illness-associated microbleeds.

Intracranial hemorrhage in COVID-19 patients during extracorporeal membrane oxygenation for acute respiratory failure: a nationwide register study report

BACKGROUND

In severe cases, SARS-CoV-2 infection leads to acute respiratory distress syndrome (ARDS), often treated by extracorporeal membrane oxygenation (ECMO). During ECMO therapy, anticoagulation is crucial to prevent device-associated thrombosis and device failure, however, it is associated with bleeding complications. In COVID-19, additional pathologies, such as endotheliitis, may further increase the risk of bleeding complications. To assess the frequency of bleeding events, we analyzed data from the German COVID-19 autopsy registry (DeRegCOVID).

METHODS

The electronic registry uses a web-based electronic case report form. In November 2021, the registry included N = 1129 confirmed COVID-19 autopsy cases, with data on 63 ECMO autopsy cases and 1066 non-ECMO autopsy cases, contributed from 29 German sites.

FINDINGS

The registry data showed that ECMO was used in younger male patients and bleeding events occurred much more frequently in ECMO cases compared to non-ECMO cases (56% and 9%, respectively). Similarly, intracranial bleeding (ICB) was documented in 21% of ECMO cases and 3% of non-ECMO cases and was classified as the immediate or underlying cause of death in 78% of ECMO cases and 37% of non-ECMO cases. In ECMO cases, the three most common immediate causes of death were multi-organ failure, ARDS and ICB, and in non-ECMO cases ARDS, multi-organ failure and pulmonary bacterial ± fungal superinfection, ordered by descending frequency.

INTERPRETATION

Our study suggests the potential value of autopsies and a joint interdisciplinary multicenter (national) approach in addressing fatal complications in COVID-19.

Brain injury in extracorporeal cardiopulmonary resuscitation: translational to clinical research

The addition of extracorporeal membrane oxygenation (ECMO) to conventional cardiopulmonary resuscitation (CPR), termed extracorporeal cardiopulmonary resuscitation (ECPR), has significantly improved survival in selected patient populations. Despite this advancement, significant neurological impairment persists in approximately half of survivors. ECPR represents a potential advancement for patients who experience refractory cardiac arrest (CA) due to a reversible etiology and do not regain spontaneous circulation. Important risk factors for acute brain injury (ABI) in ECPR include lack of perfusion, reperfusion, and altered cerebral autoregulation. The initial hypoxic-ischemic injury caused by no-flow and low-flow states after CA and during CPR is compounded by reperfusion, hyperoxia during ECMO support, and nonpulsatile blood flow. Additionally, ECPR patients are at risk for Harlequin syndrome with peripheral cannulation, which can lead to preferential perfusion of cerebral vessels with deoxygenated blood. Lastly, the oxygenator membrane is prothrombotic and requires systemic anticoagulation. The two competing phenomena result in thrombus formation, hemolysis, and thrombocytopenia, increasing the risk of ischemic and hemorrhagic ABI. In addition to clinical studies, we assessed available ECPR animal models to identify the mechanisms underlying ABI at the cellular level. Standardized multimodal neurological monitoring may facilitate early detection of and intervention for ABI. With the increasing use of ECPR, it is critical to understand the pathophysiology of ABI, its prevention, and the management strategies for improving the outcomes of ECPR. Translational and clinical research focusing on acute ABI immediately after ECMO cannulation and its short- and long-term neurological outcomes are warranted.