title: Xenon-enhanced cerebral blood flow at 28% xenon provides uniquely safe access to quantitative, clinically useful cerebral blood flow information: a multicenter study.
abstract: OBJECTIVE
  Xe-CT measures CBF and can be used to make clinical treatment decisions. Availability has been limited, in part due to safety concerns. Due to improvements in CT technology, the concentration of inhaled xenon gas has been decreased from 32% to 28%. To our knowledge, no data exist regarding the safety profile of this concentration. We sought to better determine the safety profile of this lower concentration through a multicenter evaluation of adverse events reported by all centers currently performing xenon/CT studies in the US.
  
  
  METHODS
  Patients were prospectively recruited at 7 centers to obtain safety and efficacy information. All studies were performed to answer a clinical question. All centers used the same xenon delivery system. CT imaging was used during a 4.3-minute inhalation of 28% xenon gas. Vital signs were monitored on all patients throughout each procedure. Occurrence and severity of adverse events were recorded by the principal investigator at each site.
  
  
  RESULTS
  At 7 centers, 2003 studies were performed, 1486 (74.2%) in nonventilated patients. The most common indications were occlusive vascular disease and ischemic stroke; 93% of studies were considered clinically useful. Thirty-nine studies (1.9%) caused respiratory suppression of >20 seconds, all of which resolved spontaneously. Shorter respiratory pauses occurred in 119 (5.9%), and hyperventilation, in 34 (1.7%). There were 53 additional adverse events (2.9%), 7 of which were classified as severe. No adverse event resulted in any persistent neurologic change or other sequelae.
  
  
  CONCLUSIONS
  Xe-CT CBF can be performed safely, with a very low risk of adverse events and, to date, no risk of permanent morbidity or sequelae. On the basis of the importance of the clinical information gained, Xe-CT should be made widely available.
authors.affiliation: Department of Neurosurgery, University of New Mexico, Albuquerque, New Mexico, USA.
authors.forename: A P
authors.initials: AP
authors.lastname: Carlson
authors.forename: A M
authors.initials: AM
authors.lastname: Brown
authors.forename: E
authors.initials: E
authors.lastname: Zager
authors.forename: K
authors.initials: K
authors.lastname: Uchino
authors.forename: M P
authors.initials: MP
authors.lastname: Marks
authors.forename: C
authors.initials: C
authors.lastname: Robertson
authors.forename: G P
authors.initials: GP
authors.lastname: Sinson
authors.forename: A
authors.initials: A
authors.lastname: Marmarou
authors.forename: H
authors.initials: H
authors.lastname: Yonas
mesh_terms: D000280:Administration, Inhalation; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000009:adverse effects; D001007:Anxiety / Q000139:chemically induced; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000139:chemically induced; D055420:Perfusion Imaging / Q000009:adverse effects / Q000379:methods*; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000139:chemically induced; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000379:methods*; D014978:Xenon / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D018685:Anesthetics, Inhalation; D014978:Xenon