Integrative Volume Status Assessment.

Volume status assessment is a critical but challenging clinical skill and is especially important for the management of patients in the emergency department, intensive care unit, and dialysis unit where accurate intravascular assessment is necessary to guide appropriate fluid management. Assessment of volume status is subjective and can vary from provider to provider, posing clinical dilemmas. Traditional non-invasive methods of volume assessment include assessment of skin turgor, axillary sweat, peripheral edema, pulmonary crackles, orthostatic vital signs, and jugular venous distension. Invasive assessments of volume status include direct measurement of central venous pressure and pulmonary artery pressures. Each of these has their own limitations, challenges, and pitfalls and were often validated based on small cohorts with questionable comparators. In the past 30 years, the increased availability, progressive miniaturization, and falling price of ultrasound devices has made point of care ultrasound (POCUS) widely available. Emerging evidence base and increased uptake across multiple subspecialities has facilitated the adoption of this technology. POCUS is now widely available, relatively inexpensive, free of ionizing radiation, and can help providers make medical decisions with more precision. POCUS is not intended to replace the physical exam, but rather to complement clinical assessment, guiding providers to give thorough and accurate clinical care to their patients. We should be mindful of the nascent literature supporting the use of POCUS and other limitations as uptake increases among providers and be wary not to use POCUS to substitute clinical judgement, but integrate ultrasonographic findings carefully with history and clinical examination.

Comprehensive Assessment of Fluid Status by Point-of-Care Ultrasonography.

The management of complex fluid and electrolyte disorders is central to the practice of nephrologists. The sensitivity of physical examination alone to determine fluid status is limited, precluding accurate clinical decision making. Point-of-care ultrasonography (POCUS) is emerging as a valuable, noninvasive, bedside diagnostic tool for objective evaluation of physiologic and hemodynamic parameters related to fluid status, tolerance, and responsiveness. Rapid bedside sonographic evaluation can obtain qualitative data on cardiac function and quantitative data on pulmonary congestion. Advanced POCUS, including goal-directed Doppler echocardiography, provides additional quantitative information, including flow velocities and pressures across the cardiac structures. Recently, abnormal Doppler flow patterns in abdominal organs secondary to increased right atrial pressure have been linked to congestive organ damage, adding another component to the hemodynamic assessment. Integrating POCUS findings with clinical and laboratory data can further elucidate a patient's hemodynamic status. This drives decisions regarding crystalloid administration or, conversely, diuresis or ultrafiltration and allows tailored therapy for individual patients. In this article, we provide an overview of the focused assessment of cardiovascular function and pulmonary and venous congestion using POCUS and review relevant literature.

Feasibility of Assessing Sodium-Associated Body Fluid Composition in End-Stage Renal Disease.

BACKGROUND: Cardiovascular disease accounts for more than half of all deaths in the hemodialysis (HD) population. Although much of this mortality is associated with fluid overload (FO), FO is difficult to measure, and many HD patients have significant pulmonary congestion despite the absence of clinical presentation. Cohort studies have observed that FO, as measured by bioimpedance spectroscopy (BIS), correlates with mortality. Other studies have observed that lower sodium intake is associated with less fluid-related weight gain, improved hypertension, and survival. Whether sodium intake influences FO in HD patients as measured by BIS is not known. OBJECTIVE: The aims of the study were to determine the feasibility of assessing the impact of sodium restriction on body fluid composition as measured by BIS among patients with three levels of sodium intake and to determine if there are statistical and/or clinical differences in BIS measures across sodium intake groups. METHODS: We used a double-blinded randomized controlled trial design with three levels of sodium restriction, 2,400 mg per day, 1,500 mg per day, and unrestricted (control group), to test our aims. Forty-two HD patients from a tertiary acute care academic institution associated with three urban DaVita dialysis centers were enrolled. Participants remained in the inpatient center for 5 days and 4 nights and were randomly assigned to sodium intake groups. Body fluid composition was measured with BIS. RESULTS: Recruitment, enrollment, and retention statistics supported the feasibility of the study design. Regression analyses showed that there were no statistically significant differences among sodium intake groups on any of the outcomes. DISCUSSION: Our data suggest the need for additional research into the effects of sodium restriction on body fluid composition.