Today I had the pleasure to interview Dr. Paul Marik, Professor and Division Chief of Pulmonary Critical Care at Eastern Virginia Medical Center. We got to speak on the topic of fluid responsiveness–one of the toughest questions in critical care.
The definition we are using for fluid responsiveness is an increase of stroke volume of 10-15% after the patient receives 500 ml of crystalloid over 10-15 minutes
Dr. Marik's Path through the Morass
this is a modification of the algorithm from Dr. Marik's upcoming paper
* if using passive leg raise, give a 500 ml bolus if the response is positive
What is Passive Leg Raising?
For a brief period of time, a bolus of fluid is sent to the heart, allowing you to test fluid responsiveness without doing anything permanent to the patient's fluid status.
What is the Monitor that Dr. Marik mentioned?
The NICOM Monitor by Cheetah Med uses bio-reactance to yield cardiac output/stroke volume non-invasively. I have been trialing the monitor and have been very impressed so far. It is inexpensive and correlates with my echocardiograms.
Articles of Interest
- This systematic review basically was the end of using CVP in the ICU for fluid responsiveness: Does central venous pressure predict fluid responsiveness? A systematic review of the literature and the tale of seven mares
- Marik's review of hemodynamic parameters to guide fluid therapy
- An even better review by Dr. Marik will be published in the journal Resuscitation, as soon as it is published, I'll put it up on the site
- If using Pulse Pressure Variation, probably only helpful if <9 or >13: Assessing the diagnostic accuracy of pulse pressure variations for the prediction of fluid responsiveness: a “gray zone” approach. by Maxime Cannesson (Anesthesiology. 2011 Aug;115(2):231-41.)
Neither Dr. Marik nor I have any Conflicts of Interest!
Here is an amazing review article by Dr. Marik on this topic