Cerebral and somatic near-infrared spectroscopy measurements during fluid challenge in cardiac surgery patients: a descriptive pilot study.
OBJECTIVE
Little is known about changes in near-infrared spectroscopy (NIRS)-derived cerebral (rSO(2)b) and somatic (rSO(2)s) oxygen saturation during a fluid challenge. The authors tested the hypothesis that they could differ from central venous oxygen saturation (ScvO(2)) and from one site to another.


METHODS
A prospective observational study.


METHODS
A teaching university hospital.


METHODS
Fifty consecutive adult patients.


METHODS
Admission to the intensive care unit after cardiac surgery and investigation before and after a fluid challenge.


RESULTS
Simultaneous comparative ScvO(2), rSO(2)b, and rSO(2)s data points were collected from a blood-gas analyzer and the EQUANOX monitor (Nonin Medical, Inc, Plymouth, MN). Correlations were determined by linear regression. Multiple stepwise linear regression models were used to assess independent variables associated with changes in ScvO(2), rSO(2)b, and rSO(2)s. A statistically significant relationship was found between absolute values of ScvO(2) and rSO(2)b (r = 0.42, p < 0.001) but not between absolute values of ScvO(2) and rSO(2)s (r = 0.18, p = 0.066). No relationship was found between percent changes in ScvO(2) and rSO(2)b (r = 0.05, p = 0.715) and between percent changes in ScvO(2) and rSO(2)s (r = 0.02, p = 0.886) after the fluid challenge. Cardiac index contributed to the prediction of changes in ScvO(2) (regression coefficient = -4.09, p = 0.006), whereas the mean arterial pressure contributed to the prediction of changes in rSO(2)b (regression coefficient = -0.05, p = 0.027).


CONCLUSIONS
rSO(2)b and rSO(2)s cannot be used to provide noninvasive estimation of ScvO(2), and trends in rSO(2)b and rSO(2)s cannot be considered as noninvasive surrogates for the trend in ScvO(2) after cardiac surgery. Different independent variables contribute to the prediction of ScvO(2), rSO(2)b, and rSO(2)s.
Department of Anesthesiology and Critical Care Medicine, CHU de Caen, Caen, France. fellahi-jl@chu-caen.fr
Jean-Luc
JL
Fellahi
Marc-Olivier
MO
Fischer
Olivier
O
Rebet
Audrey
A
Dalbera
Massimo
M
Massetti
Jean-Louis
JL
Gérard
Jean-Luc
JL
Hanouz
D000367:Age Factors; D000368:Aged; D000768:Anesthesia, General; D062186:Arterial Pressure / Q000502:physiology; D001923:Brain Chemistry / Q000502:physiology*; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D003422:Critical Care; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006438:Hemodilution / Q000009:adverse effects*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D020896:Hypovolemia / Q000503:physiopathology*; D002534:Hypoxia, Brain / Q000097:blood; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D010865:Pilot Projects; D011182:Postoperative Care; D012307:Risk Factors; D019265:Spectroscopy, Near-Infrared
D006454:Hemoglobins; D010100:Oxygen