title: Sitting position for removal of pineal region lesions: the Helsinki experience.
abstract: OBJECTIVE
  To present a summary of anesthetic considerations for use of the sitting position in procedures to remove lesions of the occipital and suboccipital regions, with a special reference to the Helsinki experience with more than 300 operations in 1997-2007, and a retrospective study evaluating the incidence of venous air embolism (VAE) and hemodynamic stability in patients operated in the steep sitting position.
  
  
  METHODS
  Anesthesiology reports of 72 patients with a mean (± standard deviation [SD]) age of 33 years ± 18 treated by the senior author (J.H.) for pineal region tumors using the infratentorial supracerebellar approach in the sitting position during an 11-year period were retrospectively reviewed for the incidence of VAE and hemodynamic stability.
  
  
  RESULTS
  In the sitting position, median systolic blood pressure changed -8 (-95 to +50) mm Hg without alteration in heart rate. Based on patient records, the incidence of VAE was 19% (14 of 72 patients). In five patients, end-tidal carbon dioxide (ETCO(2)) decreased more than 0.7 kPa (5.25 mm Hg), possibly indicating VAE. Comparing patients with and without VAE, no differences in change of blood pressure, heart rate, or amount of administered vasoactive agents were observed. Postoperative duration of ventilator treatment and hospital stay were similar in patients with and without VAE. No signs of arterial embolization were seen postoperatively.
  
  
  CONCLUSIONS
  The sitting position is associated with risk for hypotension. The same surgical approach and procedure does not exclude the occurrence of VAE. In this study, the unaltered hemodynamics in patients during VAE indicates relatively small VAE. Possible explanations for this are early recognition of air leakage and good cooperation between the surgical and anesthesia teams.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Helsinki University Central Hospital, Helsinki, Finland. Ann-Christine.Lindroos@hus.fi
authors.forename: Ann-Christine
authors.initials: AC
authors.lastname: Lindroos
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Niiya
authors.forename: Tarja
authors.initials: T
authors.lastname: Randell
authors.forename: Rossana
authors.initials: R
authors.lastname: Romani
authors.forename: Juha
authors.initials: J
authors.lastname: Hernesniemi
authors.forename: Tomi
authors.initials: T
authors.lastname: Niemi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004618:Embolism, Air / Q000209:etiology* / Q000517:prevention & control / Q000601:surgery; D005260:Female; D005387:Finland; D006801:Humans; D007223:Infant; D019585:Intracranial Hypotension / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects* / Q000379:methods / Q000592:standards; D056888:Patient Positioning / Q000009:adverse effects* / Q000379:methods / Q000592:standards; D010870:Pineal Gland / Q000473:pathology / Q000601:surgery*; D010871:Pinealoma / Q000601:surgery*; D012189:Retrospective Studies