Anestéziológia a intenzívna medicína 1/2017

Diagnosing hypovolemia by passive leg raising test (PLR)

Hypovolemia is relatively common in critically ill patients. There is no doubt that unrecognized and because of it untreated hypovolemia will worsen patient‘s condition. As a result, it is possible that suitable fluid resuscitation might improve the outcome of a big number of critically ill patients all over the world. The fluid resuscitation is a simple and cheap method, so diagnosis of hypovolemia is one of the barriers for optimal fluid therapy. When we determine whether a patient needs fluid therapy, we implement a diagnostic test to answer the question does this patient have hypovolemia? For reasonable answer, we must know the limitations of the different tests and use the suitable one to the specific patient. Also we have to know the cut-off point of the diagnostic test and its accuracy for hypovolemia, the positive and negative prognostic values. In an ideal world, the test must be simple and fast performing, independent on operator, noninvasive, cheap and usable to the most of patients in shock. As high positive, so and negative prognostic values are important, because extra fluid could have negative influence for the patient. The need of precise diagnostic test for hypovolemia is highlighted by the observation that only half of the patients included in trials of fluid responsiveness responded to the fluid challenge studied (1). Interpreted to everyday practice, only half of the patients we treat with resuscitation fluid will recover their cardiovascular function, the other half may show the side effects of overloading.

Keywords: hypovolemia, diagnostic test, PLR test, cardiac autput