I do not work in an intensive care unit. I am a mathematician/physicist and I collaborate with those with the necessary skills on different application areas.

The EV1000 works very well. Non-invasive and invasive modes.

It depends if the patient is mechanically ventilated or spontaneously breathing. Beside the clinical signs of dehydration, leg raise test associated with change in pulse pressure or cardiac output (by CO monitor or echo) is a good test. Most studies define fluid responsiveness as increase in CO/SV by 10-15%.

In mechanically ventilated patients, we use the heart-lung interaction and positive pressure ventilation, either by IVC assessment by echo (collapse more than 12%) or stroke volume variation (LIDCO). PICCO also is of great help.

Fluid responsiveness is a dynamic test and should be repeated through the management till the shock state had been resolved.

This has always been "the Holy Grail" question in critical care.  For intubated patients the PVI (Plethysmographic Variability Index) has been very successful (great monitor is made by Masimo in Irvine, California).  Even though I do not have a PVI monitor, whenever I have a critical patient with the question that a fluid bolus may be needed, I will look at the plethsmographic tracing to see how much variability there is.  We used to use the PA line and compare the wedge pressures, but that is more of an inferred reading and not always reliable.  The PA line also presents many risks to the patient as well.  CVP readings can also be helpful but not always reliable and like the PA line requires the insertion of a central line.  I also look at the "whole picture" of all of the vital signs, any changes in the patient's status, underlying disease, and how they have responded to any previous fluid boluses.

I never answer to these Q&A but here... How is it possible that the most basic procedure in the critically ill (give fluid or not) is still a question,  in 2016 ? Does it prove that the question is still open ?? As you can see, my answers are other questions. Since there are many tools (too many?), I added mine, see www.CEURF.net, section FALLS-protocol.

in absence of specific monitors for CO or SVV, pulse pressure variation(PPV) is useful in patients with arterial line in place in ventilated patients. Though  plathysmography variation and PVI can identify fluid responsiveness by showing increased variability, it does not respond rapidly to fluid bolus like other parameters like SVV or PPV and hence is inadequate.

May I add : we must respect all the tools available for answering this difficult question. One word on FALLS-protocol : aims at  detecting patients who can receive fluids, aims at detecting the fluid overfload at an early, infraclinical step. Tool : lung ultrasound. Issue: the FALLS-protocol wants to be validated by an absolute gold standard of clinical volemia. We currently wait for such a gold standard.

Professor Lichtenstein,

Thank you for your remarks. I asked that question to find out what is going on around the globe. I personally assess fluid responsiveness by PLR and EEO test using pulse contour analysis (Lidco system), TTE and lung ultrasound. I do not rely on one method only because of gray zones and other confounding factors. As you said we urgently need validated method and broadly accepted gold standart of fluid responsiveness assessment method. Even in Surviving Sepsis Campaign Guidelines we still have CVP monitoring which is obsolete and strange. We need it right now.

As for the use of CVP, I have observed adequate values while the SVV indicates substantial variation. I have followed this question in an attempt to glen what others have found. @TomaszCzarnik Great Question

Echo remains a very good tool, but operator dependent and not continuous. The shining side is that it can assess preload, after load, cardiac function both right and left. Apart from machine and training cost is nearly zero. In resource-limited settings, I think it has a great value.

More details: http://m.echorespract.com/content/1/1/D1.full

In my ICU the use of the lung echography is the main tool for assessing the fluid responsiveness in patients receiving or not mechanical ventilation.

We use the principles of early goal directed therapy. We use this way in patient mechanically ventilated or no.

This is indeed a very important question. The overview on fluid responsiveness is basically: There are two methods that have been repeatedly validated:

1. Dynamic variables induced by controlled positive pressure ventilation where the applied tidal volumes are higher than recommended.

2. Passive leg raising, where flow monitoring (cardiac output/stroke volume) is available.

Now, for the ICU, dynamic variables are valid in only 2-3% of ICU patients, primarily because they are not ventilated with the right ventilator settings, which is certainly justified to protect the lungs.

For passive leg raising, it is applicable but rarely done with flow monitoring (at least, in most patients admitted to Danish ICUs), and if clinicians are not experts with the echo probe and can measure flow adequately in relation to the PLR, then they are left with the blood pressure response (either MAP or pulse pressure), which is an inadequate assessment. I have never seen intensivists in Denmark measuring flow with ultrasound during a PLR.

To conclude, unfortunately we do not have really reliable and easy-to-use fluid responsiveness methods to apply broadly in the ICU, but the validated methods, dynamic variables and PLR, certainly tell us, what the ambition should be: To use a dynamic approach and (definitely!) not rely on e.g. CVP.

There are new and more applicable techniques underway, I think. Personally, I have thought of a simple physiological (dynamic) approach that I currently work on - using the preload fluctiations induced by extrasystoles that occur in most non-atrial-fibrillation ICU patients most of the time anyway... (Using extra systoles to predict fluid responsiveness in cardiothoracic critical care patients, J Clin Monit Comput. 2016 Jul 26. [Epub ahead of print])

Response to fluid challenge is usually immediately reflected in hemodynamic monitoring system that is being practiced in ICU. The most important point is the

recognition of the pathophysiology that trigerred the necessity for fluid resuscitation.

Is it severe sepsis or septic shock or capillary leak sydrome or excess fluid loss in 

situation like gastroenteritis or diabetes insipidus in Head Injury or brain death cases or cerebral salt wasting syndrome, or sepsis induced myocardial depression?. Certainly cardiogenic shock would have a different approach but the issue of dilated cardiomyopathy with severe sepsis is a complex situation. The issue of massive pulmonary embolism with shock is another complicated situation needing skilled monitoring and accurate management.

In the ICU, CVP is the commonest hemodynamic reading immediately available.

SVV is another adjuvant. But when Tricuspid regurgitation is there, PCWP is better choice. When there is continuous CO monitoring, SVV and Straight Leg Raising test

is another good adjuvant. The issue of LVEDV or Ultrasonic IVC dimension is not a

routine choice in most ICUs. Finally, every case has to be individualised and has

to be  delt accordingly.

that is 

In our Intensive Care Unit I intend to check every patient with US as a main tool to assess intrathoracic and pulmonary state following the BLUE and FALLS protocol estimating the A,B,C profiles and PLAPS. It is a reliable and convenient, tool to examine patients for fluid responsiveness receiving or not mechanical ventilation, in acoordance with PiCCO, as well.

We are all focused on fluid responsiveness. What proves us this is the right approach ?? (This is just a question, not an answer, please).

@ Daniel Lichtenstein: You have a relevant point, but I think it deserves a bit more elaboration.

Fluids are given with the primary purpose of improving hemodynamics, but fluids do not always do so and fluids have side effects. So, predicting whether fluids actually improve hemodynamics seems obviously essential, hence the need for fluid responsiveness prediction monitoring - in my opinion. It is correct, however, that for the ICU there is no RCT evidence to support "fluid responsiveness prediction" methods but that is merely because we do not yet have monitoring methods that we trust to do correct prediction that we in turn would expect to have impact on more important clinical outcomes. If we had, studies with reliable fluid responsiveness monitoring implemented in the treatment protocol would expectedly be conducted soon after.

Of note regarding previous comments in the thread, fluid responsiveness monitoring is distinct from treatment protocols/approaches, e.g. liberal, restrictive, or goal-directed.

Goal-directed therapy appears reasonably supported in major surgery, but there is no convincing support for applying a (similar)  goal-directed therapy approach in ICU patients - on the contrary.