What is PiCCO?

Recently, we admitted a very unstable motorcycle vs. van high speed collision to the Trauma ICU.  He sustained multiple injuries and remains hemodynamically unstable, not to mention extremely sensitive to each sedative, fluid bolus, and pressor we administer.   In order to continuously assess his volume and cardiac status, PiCCO will allow us to monitor real-time cardiac output.
PiCCO stands for Pulse Induced Contour Cardiac Output.  It utilizes the theory that stroke volume is proportional to arterial pulse contour. A central venous catheter as well as arterial line with an inserted thermister are required. A quantified volume of ice-cold or even room temperature saline is injected into a central vein which immediately distributes within the pulmonary and cardiac volumes -- representing intrathoracic volume.  When the thermal signal reaches the thermister within the arterial line, the temperature differential is noted and plotted onto a curve using a modified Stewart-Hamilton equation.

This equation states that

Equation from http://web.squ.edu.om/med-Lib/MED_CD/E_CDs/anesthesia/site/content/v03/030286r00.HTM

  The constant (K) adjusts for amount of thermal signal, catheter dimensions, and the material injected.


Cardiac Output remains inversely proportional to the area under the thermodilution curve. Accuracy is questioned with patients who are mechanically ventilated as stroke volume varies with the respiratory cycle; thus cardiac output will also vary.  Clinicians combat this variation by completing bolus injections at the same time of the respiratory cycle or averaging consecutive measurements.



More information can be viewed at: http://www.docstoc.com/docs/34438035/Philips-PiCCO-Technology-CMS


References:

http://www.pulsion.de/fileadmin/redaktion/Literature/Reviews/Cottis_ICCN_2003_301.pdf
http://www.healthcare.philips.com/main/products/patient_monitoring/products/picco/

thanks to Dr. Amina Merchant for this post