title: Cerebral oxygen saturation and cardiac output during anaesthesia in sitting position for neurosurgical procedures: a prospective observational study.
abstract: BACKGROUND
  Neurosurgical operations in the dorsal cranium often require the patient to be positioned in a sitting position. This can be associated with decreased cardiac output and cerebral hypoperfusion, and possibly, inadequate cerebral oxygenation. In the present study, cerebral oxygen saturation was measured during neurosurgery in the sitting position and correlated with cardiac output.
  
  
  METHODS
  Perioperative cerebral oxygen saturation was measured continuously with two different monitors, INVOS®and FORE-SIGHT®. Cardiac output was measured at eight predefined time points using transoesophageal echocardiography.
  
  
  RESULTS
  Forty patients were enrolled, but only 35 (20 female) were eventually operated on in the sitting position. At the first time point, the regional cerebral oxygen saturation measured with INVOS®was 70 (sd 9)%; thereafter, it increased by 0.0187% min-1(P<0.01). The cerebral tissue oxygen saturation measured with FORE-SIGHT®started at 68 (sd 13)% and increased by 0.0142% min-1(P<0.01). The mean arterial blood pressure did not change. Cardiac output was between 6.3 (sd 1.3) and 7.2 (1.8) litre min-1at the predefined time points. Cardiac output, but not mean arterial blood pressure, showed a positive and significant correlation with cerebral oxygen saturation.
  
  
  CONCLUSIONS
  During neurosurgery in the sitting position, the cerebral oxygen saturation slowly increases and, therefore, this position seems to be safe with regard to cerebral oxygen saturation. Cerebral oxygen saturation is stable because of constant CO and MAP, while the influence of CO on cerebral oxygen saturation seems to be more relevant.
  
  
  BACKGROUND
  NCT01275898.
authors.affiliation: Department of Anaesthesiology, University Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz 55131, Germany schrammp@uni-mainz.de.
authors.forename: P
authors.initials: P
authors.lastname: Schramm
authors.affiliation: Department of Anaesthesiology, University Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz 55131, Germany.|Department of Anaesthesiology, Christophorus-Hospital, Südring 41, Coesfeld 48653, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Tzanova
authors.affiliation: Department of Anaesthesiology, University Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz 55131, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Hagen
authors.affiliation: Institute of Medical Biometry, Epidemiology and Informatics (IMBEI), University Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz 55131, Germany.|Department of Mathematics and Technology, RheinAhrCampus Remagen, Joseph-Rovan-Allee 2, Remagen 53424, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Berres
authors.affiliation: Department of Anaesthesiology, University Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz 55131, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Closhen
authors.affiliation: Department of Anaesthesiology, University Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz 55131, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Pestel
authors.affiliation: Department of Anaesthesiology, University Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz 55131, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Engelhard
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia; D062186:Arterial Pressure; D001921:Brain / Q000378:metabolism*; D002302:Cardiac Output; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D010100:Oxygen / Q000378:metabolism*; D056888:Patient Positioning; D011446:Prospective Studies
chemical_list: D010100:Oxygen
keywords: anaesthesia; cardiac output; heart; neurosurgery; position, sitting