Abstract 13649: Asymmetric Cerebral Perfusion in Comatose Extracorporeal Membrane Oxygenation Patients

Asymmetric cerebral perfusion can occur when extracorporeal membrane oxygenation (ECMO) flow competes with native cardiac circulation. It is unclear whether this phenomenon associates with brain injury. Diffuse correlation spectroscopy (DCS) provides continuous, laser-based, non-invasive, bedside monitoring of relative cerebral blood flow (rCBF). This study measured rCBF in ECMO patients via DCS to determine whether comatose patients experience asymmetric cerebral perfusion. Adults receiving ECMO for any indication were prospectively recruited from 12/2019-3/2021. Patients with prior neurologic injury, scalp/facial lacerations, and SARS-CoV-2 infection were excluded. DCS monitoring was performed daily during ECMO support with sensors placed on bilateral foreheads. Mean arterial pressure (MAP) was continuously recorded from the bedside monitor. The Glasgow Coma Scale (GCS) was assessed by clinical staff multiple times daily with sedation pauses, if possible, per standard of care. rCBF was calculated by comparing continuous cerebral blood flow (CBF) measurements to the daily median CBF, then averaged at each MAP value. Daily rCBF asymmetry was calculated by summing the absolute difference of rCBF between the two hemispheres at each MAP value, normalized for the total MAP range experienced by the patient that day. Twelve subjects were enrolled in this study (ages 21-78, 6 with cardiac arrest, 4 with acute heart failure, 2 with ARDS) and grouped by maximum GCS motor (GCS-M) score during ECMO, with 3 “comatose” subjects (GCS-M ≤ 4), and 9 “awake” subjects (GCS-M > 4). DCS was performed over 66 sessions with a mean duration of 131.83 ± 1.13 minutes. Comatose subjects exhibited more rCBF asymmetry than awake subjects (0.28 ± 0.06 mmHg-1 vs. 0.10 ± 0.001 mmHg-1, p=0.045). No difference in asymmetry was noted between patients with or without cardiac arrest. We found that comatose ECMO subjects exhibited higher inter-hemispheric rCBF asymmetry over a range of blood pressures than awake subjects. Though our comatose sample is small, further validation of this finding and its causes, such as cerebrovascular dysregulation, is warranted.

Re-Norwood operation using femoral artery cannulation

Re-Norwood operation is technically difficult to perform and is a high risk procedure due to the underlying hypocardiac function. Herein, we describe our successful re-Norwood operation approach in a 6-month old infant with persistent severe cyanosis and aortic re-coarctation. Our procedure was performed using femoral artery cannulation to protect cerebrospinal and lower body perfusion. Safe reopening of the chest was achieved, despite strong adhesions due to prior surgeries. Our repair and anastomosis techniques are described in detail. Cardiac circulation and function improved post-surgery. The patient was maintained on anti-heart failure drug therapy after surgery while awaiting a Glenn procedure.

History in medicine: the aortic valve

This paper on the aortic valve covers five centuries. From Galenus to the first accurate drawing by da Vinci in 1515, it moves on to Harvey who described the cardiac circulation in 1628. This pivotal work was the start of new developments and inventions (stethoscope by Laennec, 1816) that progressively enabled diagnosis and treatment of aortic valve disorders. From first descriptions of aortic stenosis (Riviere, 1663) and regurgitation (Cowper, 1706), via the first clinical diagnostic procedures (Forssmann, catheterisation, 1929; Edler and Hertz, ultrasound cardiography, 1953), the story ends with ground-breaking therapeutic interventions (Hufnagel, prosthesis, 1952, and Cribier, transcatheter aortic valve implantation, 2002).

Successful multimodality management of severe pulmonary arterial hypertension during pregnancy with VA-ECMO and atrial septostomy using stent

A 30-year-old Thai woman (gravida 1, para 0) at 33 weeks gestation was referred to our hospital due to acute right ventricular failure. Pulmonary vasodilators were gradually administered before delivery. On the verge of sudden postpartum cardiac circulation collapse, she was resuscitated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Abdominal compartment syndrome was developed in the early period of the mechanical support. Knowledge of pathophysiology about pulmonary arterial hypertension during pregnancy was applied. Atrial septostomy was the effective procedure for discontinuing mechanical support (VA-ECMO) corresponding to the suitable timing for maximal effect of pulmonary vasodilators. The patient and her child were safe and discharged in 2 months after the admission.

Gross Anatomy of the Heart of Pampas Deer (Ozotoceros bezoarticus, Linnaeus 1758)

The pampas deer belongs to the Cervidae family (Artiodactyla order). It used to be a common and abundant species that had a wide distribution. However, at the end of the 19th century, the populations were decimated. In general, the hearts of mammals share many similarities, but size, shape, position, vessel organization and branching can vary among species. The objective of the present study was to describe the macroscopic morphology, topography and irrigation of the heart of the pampas deer. The anatomical study was conducted with 20 animals that had died of natural causes. The animals were studied by simple dissection. All animals had colored latex injected into one of the common carotid arteries to facilitate the visualization. The position of the heart, with a 45° axis, the presence of a double sternopericardial ligament, and the bilateral cardiac circulation were some of the notable findings.