BeneVision N Series Patient Monitor Operator’s Manual 18 - 1
18 Monitoring Cardiac Output (C.O.)
18.1 C.O. Introduction
The cardiac output (C.O.) measurement invasively measures cardiac output and other hemodynamic parameters 
using the right heart (atria) thermodilution method. A cold solution of known volume and temperature is 
injected into the right atrium through the proximal port of a pulmonary artery (PA) catheter. The cold solution 
mixes with the blood in the right ventricle and the change in blood temperature is measured with a thermistor 
at the distal end of the catheter in the pulmonary artery. The temperature change is displayed as a curve on the 
C.O. split screen, and the monitor calculates the C.O. value from this curve. The C.O. value is inversely 
proportional to the area under the curve. As cardiac output varies continuously, a series of measurements must 
be carried out to achieve a reliable C.O. average value. Always use the average of multiple thermodilution 
measurements for therapy decisions. The monitor is capable of storing 6 measurements.
C.O. monitoring is intended for adult patients only.
18.2 C.O. Safety Information
• The C.O. measurement results may be erroneous during electrosurgery.
• All invasive procedures involve risks to the patient. Use aseptic technique and follow catheter 
manufacturer's instructions.
• Use only accessories specified in this manual. Make sure that the accessories never come into
contact with conductive parts.
• C.O. monitoring is not intended for pediatric and neonatal patients.
(1) C.O. menu hard key (2) C.O. measure menu hard key (3) C.O. cable connector