ABSTRACT
Clinical assessment of intravascular volume is of paramount importance in the management of critically ill patients. Intravascular volume assessment relies on physical examination findings, weight measurements, and urine output as a means of determining a patient’s fluid status. While this approach provides a global evaluation of intravascular volume, overreliance on physical examination findings in a critically ill patient may be misleading (1,2). Furthermore, lack of data regarding individual organ perfusion and function limits the use of the physical examination as an accurate assessment of a patient’s volume status. Consequently, invasive hemodynamic monitoring using pulmonary artery catheters has been incorporated and accepted as an integral part of intensive care medicine. While pulmonary artery catheters are being widely used in many intensive care units (ICUs), concern has been raised regarding the lack of improvement in patient outcomes (3-5). An observational study involving over 5700 critically ill medical and surgical patients raised issues related to use of the pulmonary artery catheter and patient safety (6). Various reports have indicated that potential problems with the use of the pulmonary artery catheter may be related to patient selection and data interpretation (7-11). Furthermore, a recent, prospective randomized trial reported no benefit to therapy directed by the pulmonary artery catheter compared with standard care of elderly, high-risk surgical patients (12). Therefore, there is a need for novel, alternative techniques that will complement bedside findings and thereby provide an improved means of assessing intravascular fluid in critically ill patients (13). The following review will examine currently available devices and techniques to directly or indirectly determine intravascular volume status in critically ill patients.
