Spatially resolved spectroscopy (NIRO-300) does not agree with jugular bulb oxygen saturation in patients undergoing warm bypass surgery.
OBJECTIVE
Near infrared spectroscopy (NIRS) is a promising non-invasive method for continuous monitoring of cerebral oxygenation during cardiac surgery with cardiopulmonary bypass (CPB). This study was designed to study the agreement between tissue oxygen index (TOI) measured by spatially resolved spectroscopy (NIRO-300) and jugular bulb oxygen saturation (SjO2) in patients undergoing warm coronary bypass surgery.


METHODS
Seventeen patients undergoing warm coronary artery bypass surgery were studied. NIRS was continuously monitored and was averaged before CPB, five, 20, 40, 60 min on CPB, five minutes before end of CPB and ten minutes after CPB to coincide with SjO2 measurements. Bypass temperature was maintained at 34-37 degrees C.


RESULTS
Bland and Altman analysis showed a bias (TOI-SjO2) of -6.7%, and wide limits of agreement (from 16% to -28%) between the two methods. In addition, mean TOI was lower than mean SjO2 during and after CPB. We observed a statistically significant correlation between arterial carbon dioxide and SjO2 measurements (r2=0.33; P=0.0003), but the former did not correlate with TOI values (r2=0.001; P=0.7).


CONCLUSIONS
Our results demonstrate a lack of agreement between SjO2 and TOI for monitoring cerebral oxygenation during cardiac surgery. We conclude that the two methods are not interchangeable.
Ali
M S
MS
Department of Anaesthetics and Intensive Care Medicine, University of Wales College of Medicine, Health Hospital, Cardiff, UK. msali58@hotmail.com
Harmer
M
M
Vaughan
R S
RS
Dunne
J A
JA
Latto
I P
IP
D000368:Aged; D001784:Blood Gas Analysis / Q000379:methods*; D001831:Body Temperature; D002245:Carbon Dioxide / Q000097:blood; D002315:Cardiopulmonary Bypass; D005260:Female; D006801:Humans; D007601:Jugular Veins / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000502:physiology; D019265:Spectroscopy, Near-Infrared
D002245:Carbon Dioxide; D010100:Oxygen