Clinical comparison of two- and three-wavelength systems for continuous measurement of venous oxygen saturation.
OBJECTIVE
To evaluate clinically the accuracy of continuous SvO2 systems to reflect reference SvO2 values over a 24-hour period.


METHODS
Randomized clinical trial.


METHODS
Six-bed cardiac surgical intensive care unit of a 540-bed federal facility.


METHODS
Sixty postoperative cardiac patients.


METHODS
Random assignment to a two- or three-wavelength continuous SvO2 catheter for postoperative SvO2 monitoring. At 4-hour intervals over a 24-hour period, mixed venous blood samples were analyzed with a reference cooximeter and compared with the monitor value of the SvO2 catheter.


METHODS
A reference cooximeter method to measure SvO2 in mixed venous blood; SvO2 as measured by the in-line, SvO2 catheter system.


RESULTS
SvO2 measured by the three-wavelength system did not differ significantly from the reference SvO2 measurement. In contrast, SvO2 measured by the two-wavelength system was significantly lower than the reference SvO2 measurement within 4 hours of admission to the critical care unit and remained significantly lower throughout the 24-hour study period.


CONCLUSIONS
The results of this clinical study confirmed a previous study in dogs, showing that SvO2 is measured more accurately by the three-wavelength continuous monitoring system.
Chulay
M
M
Critical Care Nursing Service, Warren Grant Magnuson Clinical Center, Bethesda, MD.
Palmer
J
J
Neblett
J
J
Nancherla
A R
AR
Tripodi
D
D
Caden
D
D
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002138:Calibration; D006348:Cardiac Surgical Procedures; D002407:Catheterization, Swan-Ganz / Q000295:instrumentation / Q000379:methods*; D003422:Critical Care; D005163:Factor Analysis, Statistical; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D010092:Oximetry / Q000295:instrumentation / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D011182:Postoperative Care; D015203:Reproducibility of Results; D013815:Thermodilution / Q000295:instrumentation / Q000379:methods*
D010100:Oxygen