No redistribution of lung blood flow by inhaled nitric oxide in endotoxemic piglets pretreated with an endothelin receptor antagonist

Impairment of hypoxic pulmonary vasoconstriction in acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a serious complication of severe systemic or local pulmonary inflammation, such as caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. ARDS is characterised by diffuse alveolar damage that leads to protein-rich pulmonary oedema, local alveolar hypoventilation and atelectasis. Inadequate perfusion of these areas is the main cause of hypoxaemia in ARDS. High perfusion in relation to ventilation (V/Q<1) and shunting (V/Q=0) is not only caused by impaired hypoxic pulmonary vasoconstriction but also redistribution of perfusion from obstructed lung vessels. Rebalancing the pulmonary vascular tone is a therapeutic challenge. Previous clinical trials on inhaled vasodilators (nitric oxide and prostacyclin) to enhance perfusion to high V/Q areas showed beneficial effects on hypoxaemia but not on mortality. However, specific patient populations with pulmonary hypertension may profit from treatment with inhaled vasodilators. Novel treatment targets to decrease perfusion in low V/Q areas include epoxyeicosatrienoic acids and specific leukotriene receptors. Still, lung protective ventilation and prone positioning are the best available standard of care. This review focuses on disturbed perfusion in ARDS and aims to provide basic scientists and clinicians with an overview of the vascular alterations and mechanisms of V/Q mismatch, current therapeutic strategies, and experimental approaches.

Anesthetic Management During Surgery for Tetralogy of Fallot With Pulmonary Atresia and Major Aortopulmonary Collateral Arteries

Tetralogy of Fallot with pulmonary atresia and major aortopulmonary collaterals (TOF/PA/MAPCAs) is a heterogeneous disease with varying degrees of severity, requiring complex anesthetic management. Our institution has adopted the approach of early complete repair with incorporation of all lung segments, extensive lobar and branch segmental pulmonary artery reconstruction, and ventricular septal defect closure. While the surgical management of TOF/PA/MAPCAs has been extensively described and varies depending on the institution, there is a paucity of literature on the anesthetic management for such procedures. Herein, we describe our anesthetic management based on our own institution’s surgical approach at Lucile Packard Children’s Hospital/Stanford University.