User's Manual

Contents
20-3
SvO
2
Overview
Measurements of venous oxygen saturation (SvO
2
) provide a status indicator of
the oxygen transport system in the critically ill patient.
Low or rapidly decreasing saturation values indicate an imbalance between
oxygen consumption and oxygen delivery. Normal values reflect a balance of the
oxygen transport system or the patient’s ability to successfully compensate for
alterations in oxygen supply or demand. Continuous Sv
O
2
monitoring can reduce
the frequency of additional invasive measurements and enhance the timeliness of
intervention in the critically ill patient.
This system utilizes three-wavelength reflectance spectrophotometry to sense the
amount of light absorbed by the blood. The use of three wavelengths
compensates for changes in light reflectance from red blood cell surfaces, blood
vessel walls, and for variations in hematocrit values. Digital filtering reduces
vessel-wall artifacts.
Data acquisition begins when an Abbott Opticath catheter is positioned at a site
within the pulmonary artery. The catheter connects to an Abbott Oximetrix optical
module which contains three LEDs emitting red and infrared wavelengths of light.
The catheter returns reflected light through a second optical fiber to the optical
module. Here the light is converted to an electrical signal which the Sv
O
2
module
recognizes and displays as a saturated venous oximetry value (percent Sv
O
2
).
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Setting Up SvO2 Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Display Detail. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Preparing the Catheter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Performing Pre-insertion (in vitro) Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Inserting the Catheter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Performing Light Intensity Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Performing In Vivo Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Displaying Intensity Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Setting Alarm Limits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Setting the Light Intensity Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Adjusting Trend Display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Obtaining Oximetry Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Printing Oximetry Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Storing or Reading Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Correcting Out-of-Range Light Intensity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Correcting Insufficient Light Intensity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Correcting Calibration Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Correcting Optical Module Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Correcting SvO2 Display Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Ensuring Catheter Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
SvO2 Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14