title: Carbon dioxide field flooding reduces the hemodynamic effects of venous air embolism occurring in the sitting position.
abstract: OBJECTIVE
  Although the utility of the sitting position is undisputed for biomechanical and ergonomic reasons, it has been debated in recent years for its risks, particularly venous air embolism (VAE). In order to reduce the hemodynamic effect of VAE, we changed the composition of the surgical field air partially replacing nitrogen with carbon dioxide (CO2) that better dissolves in human tissues.
  
  
  METHODS
  First, we tested our method on a test dummy in the sitting position. Infrared CO2 sensors were placed close to the wound opening and on the facial mask of the surgeon. An oxygen sensor was connected to a computer for data recording (ALTAIR(®), MSA Safety). This model showed that 10 L/min CO2 flow provides efficient air displacement, maintaining safety for the surgeon. We reproduced the above-described surgical field environment in ten consecutive cases of posterior fossa surgery performed in the sitting position. A homogeneous group of ten patients operated in the sitting position with standard setting environment was used for control. We intraoperatively monitored VAE with trans-esophageal echocardiography (TEE), end-tidal CO2 (ETCO2), CO2 arterial pressure (PaCO2), and hemodynamic changes.
  
  
  RESULTS
  Although the percentage of VAE was 70% in both groups, hemodynamic effects occurred in 10% of cases in the study group and in 40% of cases in the control group.
  
  
  CONCLUSIONS
  Our preliminary study shows that a CO2-enriched sitting position surgical microenvironment significantly reduces the hemodynamic effects of VAE, more likely because arterial CO2 emboli are more soluble and consequently much better tolerated than air emboli.
authors.affiliation: Department of Neurosurgery, Treviso Hospital, University of Padova, Piazza Ospedale 1, 31100, Treviso, Italy.
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Longatti
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Marton
authors.forename: Alberto
authors.initials: A
authors.lastname: Feletti
authors.forename: Marco
authors.initials: M
authors.lastname: Falzarano
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Canova
authors.forename: Carlo
authors.initials: C
authors.lastname: Sorbara
mesh_terms: D001254:Astrocytoma / Q000601:surgery; D001794:Blood Pressure; D001932:Brain Neoplasms / Q000601:surgery; D002245:Carbon Dioxide / Q000008:administration & dosage*; D017548:Echocardiography, Transesophageal; D004618:Embolism, Air / Q000209:etiology*; D004806:Ependymoma / Q000601:surgery; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative; D009464:Neuroma, Acoustic / Q000601:surgery; D019635:Neurosurgical Procedures; D011187:Posture
chemical_list: D002245:Carbon Dioxide