Hemodynamic Monitoring

 

This program was originally written by Michael Zbowroski, BSRN, RRT in 1984 for Medsoft. It has revised and rewritten by Catherine K. Blaine, MA, MS, RRT and Donald Friel, MEd, RRT in 1997. Funds for this project were received through the Pew Grant for Faculty development at Community College of Philadelphia. The artwork involving the Swan-Ganz catheters and the waveform test were ably provided by Jim Dever, a 1997 graduate of the Respiratory Care Program.

 

Welcome to the Community College of Philadelphia's program on Hemodynamic monitoring. If you're nervous remember you have already participated in Hemodynamic monitoring by taking a blood pressure.

Invasive, continuous hemodynamic monitoring has become a routine procedure in the intensive care unit (ICU). This program concentrates on the Swan-Ganz catheter, which has proved to be invaluable in the management of critically ill patients with a whole range of cardiopulmonary disorders.

*"The Lee Shore" by Edward Hopper

 

First a little history of how the catheter came into being. Dr. Swan was a critical care physician who was also an avid sailor. One sunny day he was sitting on a hill overlooking San Francisco bay watching the sailboats pass by. He wondered if boats could sail in the ocean and change their position, why a catheter could not sail through the heart to different destinations and give us valuable patient information. Thus he begin experimenting with a primitive catheter whose descendants we use today routinely in the ICU.

The word monitoring implies evaluation over time. That is, we collect data and compare them to subsequent findings. We will be monitoring three values in order to evaluate the forces influencing blood pressure.

These three values are:

CVP (Central Venous Pressure)

PA (Pulmonary Artery Pressure)

PCWP (Pulmonary Capillary Wedge Pressure)

These three values in conjunction or individually provide information about the factors that influence blood pressure.

The three factors that affect blood pressure are:

1) The condition of the left Ventricle (the Pump)

  1. The volume of blood in the cardiovascular system (the Volume)

    2. * This diagram illustrates that the majority of systemic blood is stored in the veins thus venomoter tone is essential in determining preload. Secondly, during inspiration, the drop in negative pressure in the thorax from -2 to -5 helps suck blood back toward the heart (i.e., the thoracic pump).

     

  2. The relative size of the Intravascular Space (The Space)

* This diagram of the microcirculation illustrates the relationship between the veins (v), and the capillaries (c). AVA is an example of an arterial-venous anastomosis (i.e., a shunt) while PS illustrates the precapillary sphincters, (i.e., the smooth muscle that determines if blood will flow into particular capillaries, as in capillary recruitment during exercise).

 

The Swan-Ganz catheter is used most commonly on patients going into SHOCK. Shock is defined as lack of blood flow to any tissues/organs in the body. Once we diagnose the type of Shock a patient has, individualized treatment can begin.

This program will help you to understand how a Swan-Ganz catheter is used and how to interpret measured values. You may proceed through this material at your own pace in any order. If you are unfamiliar with this topic, we suggest you follow the sequence presented in the Menu.