Pulse Contour Cardiac Output (PiCCO)

PiCCO is yet another monitor on the market that attempts to give more accurate measurements for several variables.  This device uses thermodilution methods to then predict these physiologic parameters.  Using only 2 sites for monitoring and data collection, the PiCCO system provides a plethora of data.  Utilizing these endpoints, the clinician has a better sense of the pt's volume status and cardiac function, thus making the decision to start inotropic agents or continue resuscitation fluids becomes increasingly more objective.    The monitoring system is also less invasive and conforms to common practices of arterial line monitoring and CVP monitoring using common central vein catheters.  Employing patented algorithms, PiCCO combines real-time continuous monitoring through pulse contour analysis with intermittent thermodilution measurement via the transpulmonary method.       An advantage of the transpulmonary thermodilution method is that it is independent of ventilator and respiratory cycles, and therefore PiCCO gives consistent, reproducible results. Clinical studies support that cardiac output measurements obtained using the PiCCO method are comparable to those obtained using traditional right heart thermodilution.    The Stewart-Hamilton equation is used to calibrate and thus provide many of the data points.  This equation has been in use since the 1970's and has proven highly accurate.   During calibration a small bolus of cold saline (usually 15mL) is flushed through the CVC and the change in temperature is recorded by the arterial probe.  This measurement is the thermodilution and with it the graph is plotted (line is the temp but with colder temps moving up the Y axis).        Using the area under the curve and multiple derivations PiCCO is able to give estimations of:   Cardiac Output Preload via Global End-Diastolic Volume Stroke Volume Variation Systemic Vascular Resistance Cardiac contractility via Pressure Velocity Increase and Global Ejection Fraction Extravascular Lung Water   Numerous advantages have been postulated including: Complete hemodynamic monitoring Fast responding continuous monitoring of the cardiac output Direct bed side quantification of cardiac preload and pulmonary edema without complicated interpretation Fast therapy decision based on actual hard data Applicable in pediatrics No PAC-associated complications Shown to be more accurate when compared to the measurement of filling pressures No additional puncture risk by the use of the standard vascular accesses already used in the intensive care patient Safe and fast detection of sudden hemodynamic deterioration or impairment Broad range of applications in intensive and non-intensive areas: Intensive Care Unit, Operating Theater, Emergency Unit, Recovery Room Easy placement of the PiCCO catheter into a main artery Quick availability (Plug and Go) Easy handling and interpretation by doctors and nurses Less expensive and less time consuming than the interpretation of filling pressures and chest x-ray Goal directed therapy leading to an improved outcome Reduction of intensive care and hospital stay ·  Recommendations are to calibrate often in unstable pt's and always after a change of 20% of the Systemic Vascular Resistance, otherwise every 8 hours is acceptable in stable pt's. ·  The critical goal of the PiCCO system is goal directed therapy with fluids or inotropic agents or both.  As with any newer monitoring strategy, the clinician should proceed with caution and much more does need to learned about this system.  The algorithms used to predict all of these data do show much more accurate value in real pt's physiologic parameters than CVP and other methods to determine volume status and overall cardiac function.  However, there are multiple other confounding comorbidities that can affect these data and give false numbers.  The over pt trend may be more helpful in these situations and with further implementation of this monitoring system, more studies will be able to tease out how certain pt populations will affect interpretation of these data.   A review article follows that sheds light on some of these limitations.

 

Anaesth Intensive Care. 2012 May;40(3):393-409.

The PiCCO monitor: a review.

Litton E, Morgan M.

Source

Department of Intensive Care Medicine, Royal Perth Hospital, Perth, Western Australia, Australia. ed.litton@health.wa.gov.au

Abstract

Advanced haemodynamic monitoring remains a cornerstone in the management of the critically ill. While rates of pulmonary artery catheter use have been declining, there has been an increase in the number of alternatives for monitoring cardiac output as well as greater understanding of the methods and criteria with which to compare devices. The PiCCO (Pulse index Continuous Cardiac Output) device is one such alternative, integrating a wide array of both static and dynamic haemodynamic data through a combination of trans-cardiopulmonary thermodilution and pulse contour analysis. The requirement for intra-arterial and central venous catheterisation limits the use of PiCCO to those with evolving critical illness or at high risk of complex and severe haemodynamic derangement. While the accuracy of trans-cardiopulmonary thermodilution as a measure of cardiac output is well established, several other PiCCO measurements require further validation within the context of their intended clinical use. As with all advanced haemodynamic monitoring systems, efficacy in improving patient-centred outcomes has yet to be conclusively demonstrated. The challenge with PiCCO is in improving the understanding of the many variables that can be measured and integrating those that are clinically relevant and adequately validated with appropriate therapeutic interventions.

 

References:

Goepfert M, Reuter D, Akyol D, Lamm P, Kilger E, Goetz A.
Goal directed fluid management reduces vasopressor and catecholamine use in cardiac surgery patients
Intensive Care Medicine 2007; 33: 96-103

Michard F.
Bedside assessment of extravascular lung water by dilution methods: temptations and pitfalls
Crit Care Med 2007; 35:1186-92

Pulsion Medical Systems http://www.pulsion.com/index.php?id=6334

From Phillip Schafer DO