title: Experimental treatment of superior venous congestion during cardiopulmonary bypass.
abstract: OBJECTIVE
  Superior venous outflow obstruction affects cerebral perfusion negatively by reducing cerebral perfusion pressure (CPP). We present a randomized study designed to compare two alternative strategies to preserve the CPP during superior vena cava (SVC) congestion and cardiopulmonary bypass (CPB).
  
  
  METHODS
  Fourteen pigs on bi-caval CPB were subjected to 75% occlusion of the SVC flow. CPP was restored either by vasopressor treatment (VP, n = 7) or by partial relief (PR) of the congestion (n = 7). The cerebral effects of the interventions were studied for 60 min with intracranial pressure (ICP) monitoring, cerebral blood flow measurement, the near-infrared light spectroscopy tissue oxygen saturation index (StO2), arterial and venous blood gas analyses and serial measurements of the glial cell damage marker protein S100β.
  
  
  RESULTS
  Both strategies restored the CPP to baseline levels and no signs of severe ischaemia were observed. In the PR group, the venous and ICPs were normalized in response to the intervention, while in the VP group those parameters remained elevated throughout the experiment. The haemoglobin oxygen saturation in the sagittal sinus (SsagO2) was increased by both VP and PR, while significant improvement in the StO2 was observed only in the PR group. The S100β concentrations were similar in the two groups.
  
  
  CONCLUSIONS
  Experimental SVC obstruction during CPB may reduce the CPP, resulting in impaired cerebral perfusion. Both vasopressor treatment and improved venous drainage can, in the short term, individually restore the CPP during these circumstances.
authors.affiliation: Department of Surgical Sciences, Section of Cardiothoracic Surgery and Anesthesiology, Uppsala University Hospital, Uppsala, Sweden. thomas.tovedal@surgsci.uu.se
authors.forename: Thomas
authors.initials: T
authors.lastname: Tovedal
authors.forename: Gunnar
authors.initials: G
authors.lastname: Myrdal
authors.forename: Ove
authors.initials: O
authors.lastname: Jonsson
authors.forename: Maria
authors.initials: M
authors.lastname: Bergquist
authors.forename: Vitas
authors.initials: V
authors.lastname: Zemgulis
authors.forename: Stefan
authors.initials: S
authors.lastname: Thelin
authors.forename: Fredrik
authors.initials: F
authors.lastname: Lennmyr
mesh_terms: D000818:Animals; D002315:Cardiopulmonary Bypass / Q000379:methods*; D002496:Central Venous Pressure / Q000187:drug effects / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D007427:Intracranial Pressure / Q000187:drug effects / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D010100:Oxygen / Q000097:blood; D011897:Random Allocation; D064568:S100 Calcium Binding Protein beta Subunit / Q000097:blood; D019265:Spectroscopy, Near-Infrared; D013479:Superior Vena Cava Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D013552:Swine; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D064568:S100 Calcium Binding Protein beta Subunit; D014662:Vasoconstrictor Agents; D010100:Oxygen; D009638:Norepinephrine
keywords: Cardiopulmonary bypass; Cerebral protection; Venous obstruction