FloTrac

Arterial line waveforms can be analyzed in various ways to obtain information about a patient's hemodynamic status. On the basic monitor, we can get the systolic and diastolic pressures, MAP, rate, and systolic pressure variation (SPV) and pulse pressure variation (PPV). The Flotrac system is an add-on package to the normal arterial line setup to provide additional arterial line waveform analysis. The Flotrac is an analysis device patented by Edwards LifeSciences and may also be referred to by some attendings as a Vigileo.

Basic Setup

The normal arterial line setup goes in this order: catheter (in patient's artery) → pressure tubing → transducer → art line cable → vital signs monitor where the tracing is shown.

With the FloTrac, the setup goes like this: catheter → pressure tubing → special Flotrac transducer → then this connects to two different cables: the red one goes into the normal monitor where you can see the art line tracing like usual, and the green cable goes to a separate Edwards monitor on a stand that shows additional waveform analysis.

If you and your attending decide to use the FloTrac, then the night before the case, indicate on the OR request form that you will need a FloTrac in your room. Your tech should have the system set up, with the green and red cables plugged in to their respective monitors, the FloTrac transducer ready to go, and the pressure tubing primed. As you are setting up the OR for the day, you can follow the prompts on the screen to enter the patient information, including height, weight, and age.

After placing the art line using a normal catheter and the usual short pressure tubing J-loop, then hook up the FloTrac tubing to the J-loop. When zeroing the transducer, remove the cap and turn the stopcock so the transducer is open to air (just like a normal transducer), then hit "zero" on both the normal vital signs monitor and also the FloTrac screen, to zero both waveforms. Then the screen should begin to track whatever values you would like to monitor.

This is a quick video showing the basic setup. The techs will do everything before 2:01, and everything after this point you will do after you have placed the art line.

https://www.youtube.com/watch?v=myEpYNssbxU

FYI: on a normal art line transducer, we use a white tab to force flush the line. On the FloTrac transducer, this comes in the form of a blue rubber tab that you pull to flush the line.

FloTrac Waveform Analysis

The Flotrac tracks the arterial pressure by taking many pinpoint pressure readings from the transducer, and connecting these points together to form the arterial line waveform. The software then analyzes many details of this waveform (including respiratory variation, shape/curtosis of the waveform, etc), and uses this information in equations to display the cardiac output (CO), cardiac index (CI), stroke volume (SV), and stroke volume variation (SVV).

You can follow these trends, compare changes in these parameters from the baseline, and observe them during events like blood loss or a fluid challenge, to help assess a patient's volume status. It is particularly useful and most often used in cases that may have large hemodynamic shifts such as complex hepatobiliary cases, HIPECs, and traumas. It is also sometimes used in the ICU as additional volume status information.