title: Symptomatic cerebral air embolism during neuro-angiographic procedures: incidence and problem avoidance.
abstract: BACKGROUND
  While clinically symptomatic cerebral air embolism secondary to neuro-angiographic procedures is rare, the incidence in a large series of procedures is unknown. Understanding this complication's frequency and etiology is critical if systems are to be instituted to reduce its incidence.
  
  
  METHODS
  We prospectively reviewed 4,568 consecutive neuro-angiographic procedures performed between June 2000 and July 2005. The occurrence and etiology of a symptomatic air embolus was noted, and an incidence was calculated for all procedures and for diagnostic arteriograms and interventional procedures individually.
  
  
  RESULTS
  Four symptomatic cerebral arterial air emboli occurred in 4,568 neuro-angiographic procedures over the five-year period (0.08%). No events occurred in 3,150 diagnostic angiograms while four occurred during 1,418 interventional procedures (0.2%). Two cases occurred during aneurysm coiling embolization (2/548; 0.4%); one case occurred during a carotid stent placement (1/138; 0.7%); one occurred during an internal carotid artery balloon occlusion test (1/73; 1.3%). Three of these complications resulted in permanent neurologic deficits while one resulted in a transient neurologic change that cleared within 60 min of onset. Sources for the emboli included the pressurized arterial flush lines connected to internal carotid artery catheters (three cases) and sudden hypotension with air subsequently entering the internal carotid artery catheter (one case). Two patients were treated with hyperbaric oxygen therapy.
  
  
  CONCLUSIONS
  Symptomatic cerebral air embolism is a rare event during neuro-angiographic procedures. Analysis of the etiologies of this infrequent event may permit us to further reduce its incidence.
authors.affiliation: Department of Neurology, Michigan State University, Lansing, MI, USA.
authors.forename: Rishi
authors.initials: R
authors.lastname: Gupta
authors.forename: Nirav
authors.initials: N
authors.lastname: Vora
authors.forename: Ajith
authors.initials: A
authors.lastname: Thomas
authors.forename: Donald
authors.initials: D
authors.lastname: Crammond
authors.forename: Ronald
authors.initials: R
authors.lastname: Roth
authors.forename: Tudor
authors.initials: T
authors.lastname: Jovin
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
mesh_terms: D002533:Cerebral Angiography / Q000009:adverse effects*; D015331:Cohort Studies; D004618:Embolism, Air / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D004621:Embolization, Therapeutic / Q000009:adverse effects; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation; D015994:Incidence; D020766:Intracranial Embolism / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D012189:Retrospective Studies; D012307:Risk Factors