Which of the following is not useful in measuring cardiac output?

Ans. B. Central venous catheter* Central venous catheter alone is not useful for measuring cardiac output.* Various methods to measure cardiac output are as follows:- Pulmonary artery flotation catheter (PAFC): Use dye dilution and thermodilution techniques (bolus and continuous thermodilution cardiac output monitoring)- Arterial waveform analysis- Thoracic electrical bioimpedance- Fick partial rebreathing method (uses CO2 )- Aortic Doppler (transesophageal and transcutaneous)- Point-of-care Echo (transthoracic as well as transesophageal)--LVOT is analyzed for cross-sectional area (CSA) and velocity time integral (VTI). Cardiac output (CO) is measured by the formula CO=CSAxVTIxHR- Lithium dilution (uses peripheral vein)- Combined lithium dilution and pulse contour analysis