title: Large visible gas bubbles in the internal jugular vein: a common occurrence during supine radical neck surgery?
abstract: OBJECTIVE
  To establish the frequency of large visible bubbles or collections of bubbles in the jugular vein during radical neck dissection in the supine position.
  
  
  METHODS
  Prospective observation by at least two investigators of random consecutive patients scheduled for radical neck surgery.
  
  
  METHODS
  Operating room suite in a university hospital specializing in head and neck cancer surgery.
  
  
  METHODS
  Twelve consecutive ASA physical status II and III patients undergoing modified radical dissection for cancer.
  
  
  METHODS
  General anesthesia with fentanyl, oxygen (O2) 30% to 40%, nitrous oxide (N2O) 60% to 70%, and isoflurane 0.5% to 1.5%, with mechanical ventilation. Table position horizontal. Modified radical neck dissections performed by attending surgeons. Surgical field (jugular vein) carefully observed by the surgeons and an independent anesthesiologist investigator for the presence of bubbles during the dissection.
  
  
  RESULTS
  Easily visible bubbles were observed in the jugular veins of 42% (5 of 12) of the consecutive radical neck dissection patients studied. Some of the collections of bubbles were large (greater than 2.5 cm in diameter). In one case, the appearance and subsequent disappearance of bubbles was followed by a transient drop in arterial blood pressure (BP) and in end-tidal carbon dioxide (PETCO2), which was suggestive of a diagnosis of central venous air embolization.
  
  
  CONCLUSIONS
  We theorize that some unexplained, undesirable intraoperative events (hypotension, arrhythmia, and hypoxemia) during radical neck dissection could be a result of venous air embolus or paradoxical air embolus. The anesthesia community should be aware of the high frequency of these visible bubbles in the jugular veins during radical neck surgery, even in the supine position. At minimum, this phenomenon is a frequent event of intellectual interest. At worst, these bubbles may be harbingers of significant central air embolism.
authors.affiliation: Department of Anesthesiology, Eye and Ear Hospital, University of Pittsburgh, PA 15213.
authors.forename: J H
authors.initials: JH
authors.lastname: Rice
authors.forename: R M
authors.initials: RM
authors.lastname: Gonzalez
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000769:Anesthesia, Inhalation; D004618:Embolism, Air / Q000097:blood / Q000209:etiology*; D005260:Female; D005283:Fentanyl; D006801:Humans; D007530:Isoflurane; D007601:Jugular Veins / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection / Q000009:adverse effects*; D009609:Nitrous Oxide; D011446:Prospective Studies; D016683:Supine Position
chemical_list: D007530:Isoflurane; D009609:Nitrous Oxide; D005283:Fentanyl