Management of Neurogenic Pulmonary Edema and Differential Hypoxemia in an Adult Supported on Venoarterial Extracorporeal Membrane Oxygenation

Drainage From Superior Vena Cava Improves Upper Body Oxygenation in Patients on Femoral Veno-Arterial Extracorporeal Membrane Oxygenation

Objective

To investigate the feasibility of drainage from the superior vena cava (SVC) to improve upper body oxygenation in patients with cardiogenic shock undergoing femoral veno-arterial extracorporeal membrane oxygenation (VA ECMO).

Methods

Seventeen adult patients receiving peripheral femoral VA ECMO for circulatory support were enrolled. The femoral drainage cannula was shifted three times (from the inferior vena cava (IVC) level to the SVC level and then the IVC level again), all under ultrasound guidance, at an interval of 15 minutes. The blood gas levels of the right radial artery (RA) and SVC and cerebral oxygen saturation (ScO₂) were measured and compared.

Results

Fifteen patients (88.2%) were successfully weaned from ECMO, and 12 patients (70.6%) survived to discharge. The oxygen saturation (SO₂) and oxygen partial pressure (PO₂) of the RA (97.0 ± 3.5% to 98.3 ± 1.5%, P < 0.05, SO₂; 127.4 ± 58.2 mmHg to 153.1 ± 67.8 mmHg, P < 0.05, PO₂) and SVC (69.5 ± 9.0% to 75.7 ± 8.5%, P < 0.05, SO₂; 38.5 ± 5.6 mmHg to 43.6 ± 6.4 mmHg, P < 0.05, PO₂) were increased; ScO₂ was also increased on both sides (left: 50.6 ± 8.6% to 55.0 ± 9.0%, P < 0.05; right: 48.7 ± 9.2% to 52.3 ± 9.8%, P < 0.05) when the femoral drainage cannula was shifted from the IVC level to the SVC level. When the femoral drainage cannula was shifted from SVC level to the IVC level again, the SO₂ and PO₂ of RA (98.3 ± 1.5% to 96.9 ± 3.2%, P <0.05, SO₂; 153.1 ± 67.8 mmHg to 125.8 ± 63.3 mmHg, P <0.05, PO₂) and SVC (75.7 ± 38.5% to 70.4 ± 7.6%, P <0.05, SO₂; 43.6 ± 6.4 mmHg to 38.9 ± 4.5 mmHg, P <0.05, PO₂) were decreased; ScO₂ was also reduced on both sides (left: 55.0 ± 9.0% to 50.7 ± 8.2%, P < 0.05; right: 52.3 ± 9.8% to 48.7 ± 9.3%, P <0.05).

Conclusion

Drainage from the SVC by shifting the cannula upward could improve upper body oxygenation in patients with cardiogenic shock undergoing femoral VA ECMO. This cannulation strategy provides an alternative solution for differential hypoxia.

Veno-arteriovenous (V-AV) ECMO configuration: A single-center experience

BACKGROUND

With increasing extracorporeal membrane oxygenation (ECMO) utilization over the last decade, clinicians have developed "hybrid" configurations to meet complex perfusion requirements. In the setting of differential hypoxemia, a veno-arteriovenous (V-AV) configuration provides oxygenated cardiac preload and hemodynamic support to satisfy physiologic demands. We aim to further characterize the patient population, indications, and outcomes associated with this hybrid configuration.

METHODS

We retrospectively reviewed all adult patients placed on V-AV ECMO at our institution from June 2016 to December 2019. Through a review of the electronic medical records, data describing demographic features, comorbidities, and ECMO-specific information were analyzed systematically.

RESULTS

14 patients were placed on V-AV ECMO during the study period. Our cohort was 79% male with a median age of 54 and BMI of 30.3. These patients had a median SOFA-0 score of 15 and SAVE score of -12. Patients were treated with ECMO support for a median of 144.1 (IQR 98.5 - 183.1) hours, consisting of 0.2 (IQR 0 - 17.7) hours of VA and 92.4 (IQR 53.7 - 115.1) hours of V-AV followed by 67.4 (IQR 20.3 - 96.6) hours of VV support. Of these 14 patients, 11 survived to decannulation (79%) and 9 survived to hospital discharge (64%).

CONCLUSION

ECMO patients with recovering left ventricular function and persistent gas exchange abnormalities are at risk for developing differential hypoxemia. We describe an approach to utilizing V-AV configuration when the likelihood of differential hypoxemia is extremely high, with a survival rate that compares favorably to Extracorporeal Life Support Organization statistics and published case series.

Neurocognitive impairments and brain abnormalities resulting from opioid-related overdoses: A systematic review

BACKGROUND

Non-fatal opioid-related overdoses have increased significantly over the past two decades and there have been increasing reports of brain injuries and/or neurocognitive impairments following overdose events. Limited preclinical research suggests that opioid overdoses may cause brain injury; however, little is known about such injuries in humans. The purpose this systematic review is to summarize existing studies on neurocognitive impairments and/or brain abnormalities associated with an opioid-related overdose in humans.

METHODS

PubMed, Web of Science, Ovid MEDLINE and PsyINFO were searched, without year restrictions, and identified 3099 articles. An additional 24 articles were identified by reviewing references. Articles were included if they were published in English, reported study findings in humans, included individuals 18 years of age or older, and reported an objective measure of neurocognitive impairments and/or brain abnormalities resulting from an opioid-related overdose. Six domains of bias (selection, performance, attrition, detection (two dimensions) and reporting were evaluated and themes were summarized.

RESULTS

Seventy-nine journal articles, published between 1973-2020, were included in the review. More than half of the articles were case reports (n = 44) and there were 11 cohort studies, 18 case series, and 6 case-control studies. All of the studies were categorized as at-risk of bias, few controlled for confounding factors, and methodological differences made direct comparisons difficult. Less than half of the studies reported toxicology results confirming an opioid-related overdose; 64.6 % reported brain MRI results and 27.8 % reported results of neuropsychological testing. Only two studies had within subject comparative data to document changes in the brain possibly associated with an overdose. Despite these limitations, existing publications suggest that brain injuries and neurocognitive impairments are associated with opioid overdose. Additional research is needed to establish the incidence of overdose-related brain injuries and the potential impact on functioning, as well as engagement in treatment of substance use disorders.

CONCLUSIONS

Respiratory depression is a defining characteristic of opioid overdose and prolonged cerebral hypoxia may cause brain injuries and/or neurocognitive impairments. The onset, characteristics, and duration of such injuries is variable and additional research is needed to understand their clinical implications.

Hybrid extracorporeal membrane oxygenation

Veno-venous (VV) and veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) therapy is widely used in critically ill patients with refractory cardiogenic shock and cardiac arrest or suffering from severe respiratory failure. Besides traditional ECMO cannulation, changes in patients' conditions or the occurrence of specific complications (i.e., cerebral hypoxia or left ventricular dilation) may require modifications in cannulation strategies or the combination of ECMO with additional invasive or minimally invasive procedures, to improve organ function and ECMO efficiency. In this review, we described all these "hybrid" approaches, such as the addition of a third or fourth ECMO cannula to improve venous drainage and/or optimize systemic hemodynamics/oxygenation, or the implementation of surgical or percutaneous unloading of the left ventricle (LV), to reduce cardiac dilation and pulmonary edema. Although few data are still available about the effectiveness of such interventions, clinicians should be aware of these advances in ECMO management to improve the management of more complex cases.