What is the best way to assess volume status?
Khalid Azzam, MD: In terms of volume status examination, we are traditionally used to physical exams with vital signs, skin turgor, auscultation, S3, rales in the lung, as well as jugular venous pressure (JVP). Internists and physicians who practice inpatient medicine or acute medicine pride themselves very much in JVP examination; however, we know that the accuracy of JVP examination is really poor and the interrater reliability is not up to par.
Using point-of-care ultrasound (PoCUS) in assessing your right-sided and left-sided filling pressures gives you a good idea about patients with difficult physical examination—which may be due to body habitus, obesity, short neck—whom you cannot really assess by physical exam. You do not know whether they are intravascularly depleted or intravascularly overloaded, especially when you are dealing with situations where the patient is a bit hypotensive and you do not know whether to give them fluids, whether they are in shock, whether they need inotropes, and what their volume status is exactly. So using ultrasound and mostly focusing on inferior vena cava (IVC) assessment, the size of the IVC, the IVC collapsibility, and calculating delta IVC or collapsibility index, looking at the lung and seeing if there is an interstitial pattern with B-lines which could be indicative of fluid, maybe pleural effusion, maybe acidic fluid—that all can be assessed easily with bedside ultrasound.
You can look at the left-sided pressures as well, and in a certain group of patients we find that there is discordance between left-sided pressure and right-sided pressure. You can calculate your stroke volume and cardiac index by using your ultrasound and coming up with a very good idea of whether the patient is really intravascularly depleted or expanded, whether they need inotropes, fluids, or diuretics based on your findings with a significant certainty compared to just doing the physical examination without the use of ultrasound.