title: Thoracic epidural anesthesia increases tissue oxygenation during major abdominal surgery.
abstract: Intraoperative surgical stress may markedly increase adrenergic nerve activity and plasma catecholamine concentrations, which causes peripheral vasoconstriction and decreased tissue oxygen partial pressure possibly leading to tissue hypoxia. Tissue hypoxia is associated with an increased incidence of surgical wound infections. Thoracic epidural anesthesia blocks afferent neural stimuli and inhibits efferent sympathetic outflow in response to painful stimuli. Consequently, we tested the hypothesis that supplemental thoracic epidural anesthesia during major abdominal surgery improves tissue perfusion and subcutaneous oxygen tension. Thirty patients were randomly assigned to two groups: general (n = 15) or combined general and epidural anesthesia (n = 15). Anesthesia technique and fluid management were standardized. Subcutaneous tissue oxygen tension was measured continuously in the upper arm with a Clark type electrode. Data were compared with unpaired, two-tailed t-tests, Wilcoxon's ranked sum test, or repeated-measures analysis of variance and Scheffé F tests as appropriate; P < 0.05 was considered statistically significant. After 60 min, intraoperative tissue oxygen tension was significantly larger during combined anesthesia than during general anesthesia (54.3 +/- 7.4 mm Hg versus 42.1 +/- 8.6 mm Hg; P = 0.0002). Subcutaneous tissue oxygen tension remained significantly higher in the combined general/epidural anesthesia group throughout the observation period. Hemodynamic responses and global oxygen variables were similar in the groups. Thoracic epidural anesthesia improved intraoperative tissue oxygen tension outside the area of the epidural block. Thus, our results give evidence that supplemental neural nociceptive block blunts generalized vasoconstriction caused by surgical stress and adrenergic responses.
  
  
  CONCLUSIONS
  Thoracic epidural anesthesia blunts the decrease of subcutaneous tissue oxygen tension caused by surgical stress and adrenergic vasoconstriction during major abdominal surgery. Consequently, combined general and epidural anesthesia helps to provide sufficient tissue oxygenation.
authors: *Department of Anesthesiology, Washington University, St. Louis, Missouri, †Department of Anesthesiology and General Intensive Care and ‡Anesthesiology and Intensive Care Medicine, Vienna General Hospital, University of Vienna, Austria; §Department of Anesthesiology, University of Berne, Switzerland; and ∥Outcomes Research Institute™, University of Louisville, Kentucky.
authors: Barbara
authors: B
authors: Kabon
authors: Edith
authors: E
authors: Fleischmann
authors: Tanja
authors: T
authors: Treschan
authors: Akiko
authors: A
authors: Taguchi
authors: Stephan
authors: S
authors: Kapral
authors: Andrea
authors: A
authors: Kurz
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000767:Anesthesia, Epidural; D001132:Arm / Q000098:blood supply; D001166:Arteriovenous Shunt, Surgical; D001785:Blood Gas Monitoring, Transcutaneous; D001794:Blood Pressure / Q000502:physiology; D002496:Central Venous Pressure / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology