title: Evaluation of a regional oxygen saturation catheter for monitoring SjvO2 in head injured patients.
abstract: OBJECTIVE
  Monitoring jugular venous oxygen saturation (SjvO2) has been useful for the early identification and treatment of cerebral ischemia in patients with severe head injury. However, the catheters that have been used for this purpose have not performed optimally. The purpose of this study was to evaluate the performance of a new regional oxygen saturation catheter for monitoring SjvO2.
  
  
  METHODS
  Eighteen regional oxygen saturation catheters, 4-Fr in diameter (Baxter Healthcare Corporation, Edward Critical Care), were used in this study. Each catheter was inserted percutaneously into the dominant jugular vein and the catheter's tip position in the jugular bulb was verified by radiograph. The catheter was calibrated in vitro prior to insertion using the optic calibrator provided by the manufacturer. The catheter was recalibrated every 8 to 12 hours by comparing the oxygen saturation value from the catheter with that measured by a co-oximeter in a blood sample drawn through the catheter.
  
  
  RESULTS
  In vitro calibration using the optic calibrator was not always successful. Five catheters could not be calibrated. The remaining 13 catheters could all be calibrated, but only 9 provided a value that was within 4% of the oxygen saturation derived from the blood sample. After the first in vivo calibration, the correlation between the catheter and the blood sample values was improved. A total of 196 comparisons were made. The median, 25th, and 75th quartile differences between the catheter and the blood sample measurement of SjvO2 were 0.00, -1.15, and 1.25%, respectively. Using longitudinal data regression, the overall slope of the regression between the catheter and blood values was 0.997 (p = 0.001).
  
  
  CONCLUSIONS
  The new regional oxygen saturation catheter provided reliable measurement of SjvO2 83% of the time when the signal quality index was < or = 3, and may be useful for continuous monitoring of SjvO2.
authors.affiliation: Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Ritter
authors.forename: S P
authors.initials: SP
authors.lastname: Gopinath
authors.forename: C
authors.initials: C
authors.lastname: Contant
authors.forename: R K
authors.initials: RK
authors.lastname: Narayan
authors.forename: C S
authors.initials: CS
authors.lastname: Robertson
mesh_terms: D001784:Blood Gas Analysis / Q000295:instrumentation*; D001930:Brain Injuries / Q000097:blood; D002404:Catheterization / Q000295:instrumentation*; D006259:Craniocerebral Trauma / Q000097:blood*; D005069:Evaluation Studies as Topic; D006801:Humans; D066298:In Vitro Techniques; D007601:Jugular Veins; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood*; D013345:Subarachnoid Hemorrhage / Q000097:blood
chemical_list: D010100:Oxygen