title: Near-infrared spectroscopy as a possible device for continuous monitoring of arterial carbon dioxide tension during cardiac surgery.
abstract: BACKGROUND
  Insufflation of carbon dioxide (CO(2)) to the operative field has been used to prevent major organ injury attributed to air embolisms in cardiac surgery. However, it may be preferable to avoid hypercapnia induced by CO(2) insufflation, owing to its potentially harmful effect. To investigate the effectiveness of near-infrared spectroscopy (NIRS) as a possible method for continuous monitoring of arterial CO(2) tension during cardiac surgery, we evaluated the correlation between the change in arterial CO(2) tension and the change in regional cerebral oxygen saturation (rScO(2)) obtained from NIRS in as controlled a condition as possible.
  
  
  METHODS
  Thirty patients who underwent surgical correction for atrial or ventricular septal defects were enrolled in this study. Patients who had pulmonary hypertension or other intracardiac anomalies were excluded. Anesthetic and cardiopulmonary bypass (CPB) management were conducted according to our standard institutional practice. Data obtained from arterial blood gas analyses and corresponding regional cerebral oxygen saturation (rScO(2)) recorded from NIRS before and after the insufflations of CO(2) during CPB were used for analysis.
  
  
  RESULTS
  The change in arterial CO(2) tension correlated with the change in rScO(2) in the left hemisphere (r = 0.681, p <0.001, y = -1.393 + 0.547x) and right hemisphere (r = 0.690, p <0.001, y = -1.999 + 0.486x). To control the effects of other variables, including hematocrit and temperature, these relationship were not reduced (left hemisphere: r=0.678, p<0.001; right hemisphere: r=0.634, p<0.001).
  
  
  CONCLUSIONS
  Since the change in regional cerebral oxygen saturation was correlated with the change in arterial CO(2) tension during mild hypothermic CPB, NIRS might be a possible non-invasive method for monitoring of arterial CO(2) tension without incurring additional cost in this setting.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Sejong General Hospital, Sejong Heart Institute, Bucheon, Republic of Korea. hopang1974@hanmail.net
authors.forename: C S
authors.initials: CS
authors.lastname: Park
authors.forename: J G
authors.initials: JG
authors.lastname: Kwak
authors.forename: C
authors.initials: C
authors.lastname: Lee
authors.forename: C-H
authors.initials: CH
authors.lastname: Lee
authors.forename: S K
authors.initials: SK
authors.lastname: Lee
authors.forename: Y L
authors.initials: YL
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D001831:Body Temperature; D002245:Carbon Dioxide / Q000097:blood*; D006348:Cardiac Surgical Procedures / Q000379:methods; D002315:Cardiopulmonary Bypass / Q000379:methods*; D002552:Cerebral Ventricles / Q000098:blood supply / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D006325:Heart Atria / Q000601:surgery; D006352:Heart Ventricles / Q000601:surgery; D006400:Hematocrit; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide