There is no question that attempts to quantify volume responsiveness should be made in both surgical and medical patients who are ill. The determination of volume responsiveness in the setting of hypotension for instance is critical when determining first-line therapy. Patients in need of volume alone should not receive pressers and vice versa. Some may need volume and pressers or volume and inotropes (volume responsive and low tone or volume responsive and in need of inotropic support). I advocate a global approach to understanding a given patient's hemodynamics. delta IVC diameter, dynamic indices, measures of delta stroke volume, response to passive leg raise, even carotid artery flow should ALL be considered when caring for a given patient. The critical component, especially when caring for the critically ill, is that the physician must be ever cognizant of false-positives (ex: high dynamic index in right heart failure: the patient may be volume responsive or may not be- another test like delta stroke volume or measuring tricuspid annular systolic velocity by echo should be considered to confirm). Volume assessment should be standard in the care of all hospitalized patients. Thanks to the work of Doppler, Atzler, Forssman, Erlanger and others, we now have a host of tools which can be used to define who our patients are. JBMD

Ultrasound is still not a reliable approach to assess the volume status, such as patients with a dilated ventricle. Actually, there exists no approach to quantify the volume up to now. The way we consider helpful is to assess the volume responsiveness and do it repeatedly.

Ultrasound estimation is ONE of several methods of assessing volume responsiveness in haemodynamically unstable patients. As such, it provides a piece of the larger jigsaw puzzle, and together with other information will provide you with a better assessment than MAP or clinical judgement alone.

As with any monitoring technique, one needs to be aware of the advantages and pitfalls of ultrasound. For IVC filling and diameter, remember that different indices are used for spontaneously breathing and mechanically ventilated patients. Remember also that PEEP can convert a volume-responsive patient to a non-volume responsive one.

As far as I know (please correct me if I'm wrong) ultrasound can primarily only estimate volume status NOT volume responsiveness. In general we want to know if the engine needs more fuel or if it can be pushed to work harder (inotropy). A spot measurement of what effect the engine is giving at current demand and fuel mixture (which we actually know very little about) is of secondary importance because if we're asking ourselves the question, we're already making a (probably correct) guess about the heart producing too little effect. Even if we look at volume status, which ultrasound does quite well, it has NOTHING to do with volume responsiveness. It is well proven that any specific CVP value tells us nothing of wether the patient will benefit from fluids or not. Except for the extreme cases where simply looking at the patient would give us the same information i.e. the patient is in shock with obvious signs of hypovolemia. A reliable way of assessing volume responsiveness is what we need.

I do value ultrasound greatly, I do truly, but there seems to be a great deal of hyperbole about it's use as a hemodynamic tool.

I agree with Staffan Höstman, that the Ultrasaound, USG, doesnt allways give the answers you need, allthough you can measure specifice volumes of the heart as well as flows of volumes.

But in the clinical expirance I have meet, I have found The Navigator does give a lot better information of blodflow as well as volumes therapy for example during anesthesia and also in the critically ill patient.The Navigator is fairly simple to adapt too also. It does give good guidance to the effects of your actions during anesthesia too.

http://www.applied-physiology.com/wp-content/uploads/Navigator-brochure-download.pdf

Great conversation. I am concerned about the term "volume status." Concerned because, in and of itself, it has no specific definition. One can assume, I think, that volume responsiveness is exactly what we want to know. I vote, we abandon the term volume status OR define it specifically. As to the comments relative to echo, it is true that echo derived IVC diameter is not predictive of volume responsiveness, however, dynamic echo indices (as recently reviewed by Levitov and Marik (doi:10.1155/2012/819696) such as Delta IVC diameter are. Today, meaningful hemodynamic interpretation relative to volume responsiveness can be summarized by the following- "It is all about the delta."

I'm always concerned when I hear people looking at IVC size with Echo and trying to estimate volume. It is an indirect measure of Right atrial pressure only and not a measure of volume. preload is actually end-diastolic volume, and with echocardiography whether by transthoracic or transoesophageal route, can estimate left and right ventricular volume directly. however volume alone does not really give you a complete answer, nor does it indicate whether you need to give volume or use another therapy. What we actually need is to diagnose the haemodynamic state. Haemodynamic state is a combination of right and left ventricle function, and pulmonary and systemic circulations. It can be broadly categorised into conditions such as "empty", "systolic failure", primary diastolic failure, combined systolic and diastolic failure, vasodilation or right ventricular failure. for example, in diastolic heart failure the left ventricle appears a little empty, but there is a high left atrial filling pressure and distended left Atrium. This accounts for 50% of heart failure patients. It is poorly responsive to fluid administration, yet paradoxically sensitive to hypovolaemia. yet if you only look at the left ventricular volume, you could incorrectly diagnosed this as "empty". basic haemodynamic state assessment provides a much higher order of diagnosis, which should provide the clinician with a rational approach to therapy, rather than using the brainstem reflex of simply administering more fluid and see if it improves the BP.

So I see the great value of echocardiography is providing answers to the clinical questions that come from your history and examination of the patient. It gives a very rapid assessment of what the basic haemodynamic problem is, providing you look at more than a single dimension (IVC or LV dimension). I'm involved in a lot of education in echocardiography, and if you want to find out more-visit my website www.heartweb.com

I have been using US evaluation of the IVC for over 3-4 year clinically. A collapsing IVC allows me to aggressive volume resuscitate patients. In patient's with a non-respirophasic IVC, I evaluate the heart and the lung to look for lack of forward flow. Server CHF, TR or elevated pulmonary artery pressures are some of the items that can cause a large (non-collapsing) IVC in patients who would still benefit from fluid.

In very recent publication , physiological explanation of IVC variations are explained. http://ccforum.com/content/16/6/181. But, I find that delta of IVC diameter in a critical care patient, with the movement of diaphragm is very difficult to appreciate.For this reason and for quality of views I definitively prefer Superior vena cava variations for estimate volume status.

http://ccforum.com/content/16/6/181

I agree with Colin Royce. It is potentially misleading to look at single measurements or indices in determining a patient's haemodynamic state. IVC diameter or even delta IVC will give only one part of the answer, and will be un interpretable in some patients (RV infarct, acute cor pulmonale, moderate or greater grade of TR, tamponade, PEEP, NIV ...). A complete systematic approach is required: is the LV systolic function intact? Is the diastolic filling profile normal (if not, patient may require higher than "normal" LA pressures in order to generate adequate cardiac output)? What is the status of the IVC? Is the RV functioning normally? Is there a pericardial problem? What about the lungs on ultrasound (wet, dry, interstitial problem, pneumothorax?)? Any other clues (EFAST)? Only then can an assessment be made of the patient's suspected pathophysiology. Confirmation is only provided by documentation (clinical or ultrasound indices) of improvement after correction of the putative deficit.

Thanks to everyone for their answers, and I not only appreciate your contributions, and agree with most. It is important to point out that I did not suggest that assessment of IVC filling or response be used as some point-of-care 'yes or no' device, or a single index, but asked a simpler question about it's potential to contribute to overall assessment of haemodynamic status. Apologies if that was not clear, or if it led to apoplexy. In actual fact, I am more interested in evaluating vascular filling in instances where the patient is notionally 'hypervolaemic' rather than the other way round. The assumption of 'fluid overload' is a situation that is exceedingly common and is recurrently mismanaged by generation after generation of medical practitioners.

In that case, I think the answer is often in the lungs! Large rigid IVC with lung ultrasound not showing B lines in greater than 2 lung zones is "ok", whereas B lines in greater than 2 zones equals "wet"

Thanks Adam. Handy references?

Yes. Ultrasound is a wonderful way to assess this due to its non-invasive, repeatable, and validated properties. I certainly use it. Attached are a couple podcasts related to this.

http://www.ultrasoundpodcast.com/2012/02/episode-22-fluid-responsiveness-part-1/

Here's part two of the fluid responsiveness podcast:

http://www.ultrasoundpodcast.com/2012/02/episode-23-fluid-responsiveness-part-2/

References for B-line appearance as an end-point to fluid resuscitation (ie fill them up until they are wet !!):

http://ccforum.com/content/16/S1/P248

and

Daniel Lichtenstein's FALLS protocol:

http://www.researchgate.net/publication/223135347_Fluid_administration_limited_by_lung_sonography_the_place_of_lung_ultrasound_in_assessment_of_acute_circulatory_failure_%28the_FALLS-protocol%29

Article Fluid administration limited by lung sonography: The place o...

As a vet, I used to also check the MABP response of the patient to the resuscitated volume. Furthermore considering the diastolic BP as a measure for vasoconctraction may sometimes help.

It is well known that too much fluid is bad for you and most intensivists now are very aware of the detrimental effects fluids can have in the septic patient with capillary leak (the Ebb Phase). However, in the early phase of resuscitation in a haemodynamically unstable patient, your priority is adequate tissue perfusion with aggressive management to maintain MAP. Many tools are available to help us in the initial resuscitation process including US IVC but my priority would be MAP initially. I do believe that by day three (approximate) when your patient is responding to the treatment (MV, Vasopressors, antibiotics, CVVHD,....) , when capillary leak is in restoration phase (The Flow Phase), judicious fluid management is of utmost importance. That is when IVC evaluation with US becomes important amongst other parameters (EVLWI, GEDVI, capillary leak index, Intra abdominal pressure,...) to avoid further positive fluid balance which is associated with increased mortality. We all remember the typical "Michelin man" patient in ICU, difficult to ventilate, oedematous, with ongoing surgical issues and high intra-abdominal pressures.

So yes I would use US guided IVC fluid management but not in the early phase of resuscitation/shock, but more in the recovery phase after the initial event.

Fluid management in a critically ill patient is notoriously difficult, probably it is best managed by careful clinical evaluation and using the best evidence. I find it useful to depend on the dynamic variables like Stroke volume variation mainly but always relate that to other variables like Blood Pressure, Systemic vascular resistance, stroke volume to come up with the best possible management for the patient.

There are several tools to assess volume status and right cardiac function. Ultrasound is a simple and practice method for clinicians.

For trauma patients, you ca assess hemoperitoneum with a linear equation on US (Baque´ P, et al. A new method to approach exact hemoperitoneum volume in a splenic trauma model using ultrasonography. Surg Radiol Anat, 2005, 27:249–253) or CT (Massalou, et al. CT quantification of hemoperitoneum volume in abdominal haemorrhage: a new method. Surg Radiol Anat 2012, dec)

U/S is vital for assessing a critically ill patient requiring resus, not just for predicting preload responsiveness, but because of the other information you can glean....check a FAST, r/o Pneumothorax, breif echo. Blood pressure alone provides too little information, too late.

Hi,

As we all patiently await technology to catch up with ideals, utilization of US to assess volume status is a relevant component of the information tapestry needed to care for critically ill/injured patients. Blood pressure(MAP), CVP, urine output, CI,EF, and US evaluation of IVC diameter all count towards the "picture" of the patient. In our institution we have infrequently attempted to utilize this methodology mostly due to inexperience with technique and interpretation...and forgetfulness of the availability. The US evaluation of IVC diameter in the setting of presumed hypovolemia is non-invasive, readily available, and potentially insightful (similiar to the echocardiogram). Preliminary evidence of potential benefit was demonstrated in research addressing the "transient responder" population of trauma patients who demonstrated a reduced IVC diameter when compared to" responders" (to standard resuscitative measures). So, to answer your question... we do not on a regular basis... and probably should moving forward.

Yanagawa Y, Sakamoto T, Okada, Y. Hypovolemic shock evaluated by sonographic measurement of the inferior vena cava during resuscitation in trauma patients. Journal of Trauma & Critical Care. December 2007; 63:1245-1248.

Does anyone know how to adress this issue in the neonatal patient: a septic and hypotensive neonate, in shock? How to guide volume administration besides heart rate, capillary refil, tension values, etc?

I consider that is a very important tool, especially when the patient have special characteristics ( eg. aging, CHF). I evalue the lines B pattern and ICV diameter. We see daily the outcomes with the edematous patients at the critical areas, and I agree that isn`t only an cosmetic problem. Not all low MAP or urinary output are caused by fluid depletion.

When it is available, we have found utility using IVC compressibility (passive or "sniff test" if patient is capable), RV collapse and qualitative assessment of LV filling and contraction. Anecdotally, it is useful in field resuscitation not only to estimate start point, but to guide permissive-hypotensive resuscitation en route to surgery.

Its better to do