Evaluation of an ultrasonic blood volume monitor

Johner, C; Chamney, Paul; Schneditz, Daniel; M, Kramer

doi:10.1093/ndt/13.8.2098

Cited by 57 publications

(52 citation statements)

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“…RPV monitoring technology uses optical transmission/optical absorbance [100] to measure the intradialytic concentration change of hemoglobin/hematocrit [101,102,103] or it uses ultrasound speed in blood to measure the concentration of total plasma proteins including hemoglobin [104,105,106]. The original aim of RPV monitors was to prevent intradialytic hypotension and related morbid events [107].…”

Section: Methods Of Dry Weight Assessment: An Overviewmentioning

confidence: 99%

Significance of Interdialytic Weight Gain versus Chronic Volume Overload: Consensus Opinion

et al. 2013

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Predialysis volume overload is the sum of interdialytic weight gain (IDWG) and residual postdialysis volume overload. It results mostly from failure to achieve an adequate volume status at the end of the dialysis session. Recent developments in bioimpedance spectroscopy and possibly relative plasma volume monitoring permit noninvasive volume status assessment in hemodialysis patients. A large proportion of patients have previously been shown to be chronically volume overloaded predialysis (defined as >15% above ‘normal' extracellular fluid volume, equivalent to >2.5 liters on average), and to exhibit a more than twofold increased mortality risk. By contrast, the magnitude of the mortality risk associated with IDWG is much smaller and only evident with very large weight gains. Here we review the available evidence on volume overload and IDWG, and question the use of IDWG as an indicator of ‘nonadherence' by describing its association with postdialysis volume depletion. We also demonstrate the relationship between IDWG, volume overload and predialysis serum sodium concentration, and comment on salt intake. Discriminating between volume overload and IDWG will likely lead to a more appropriate management of fluid withdrawal during dialysis. Consensually, the present authors agree that this discrimination should be among the primary goals for dialysis caretakers today. In consequence, we recommend objective measures of volume status beyond mere evaluations of IDWG.

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Section: Methods Of Dry Weight Assessment: An Overviewmentioning

confidence: 99%

Significance of Interdialytic Weight Gain versus Chronic Volume Overload: Consensus Opinion

et al. 2013

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“…Hct and relative blood density changes online during HD have been advocated as tools for assessing blood volume (BV) changes induced by ultrafiltration (UF) (1). The assumptions that changes in the measured systemic Hct (Hct sys ) result solely from circulating plasma volume (PV) changes induced by UF and that there is uniform mixing of a constant circulating mass of red cells and plasma components in the whole circulation during UF form the basis of such indirect measurements.…”

mentioning

confidence: 99%

The Relationship Between Systemic and Whole-Body Hematocrit Is Not Constant during Ultrafiltration on Hemodialysis

Mitra¹,

Chamney

Greenwood

et al. 2004

Journal of the American Society of Nephrology

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Abstract. The measurement of relative blood volume (RBV) changes during ultrafiltration assume a constant mass and distribution of circulating blood components such as hematocrit. The authors examine the validity of this assumption in 10 subjects undergoing repeated direct measurements of systemic hematocrit and plasma volume (PV icg ) using indocyanine green dilution at four stages of dialysis with intermittent ultrafiltration. Ultrasonic RBV changes were monitored. Absolute blood volumes (ABV) were initially derived for each PV icg estimate, and corresponding measured systemic hematocrit was adjusted by a factor of 0.86 to correct for the difference between the systemic and whole-body hematocrit (constant Fcell ratio). PV icg and ABV changes correlated closely (R ϭ 0.98; P Ͻ0.001). ABV changes overestimated reduction in PV icg during ultrafiltration (mean difference, Ϫ140 Ϯ 202 ml). The calculated red cell mass however was variable (P Ͻ0.01). Fcell ratio was then adjusted at each blood volume measurement (Fcell 1 , 0.87 Ϯ 0.02; Fcell 2 , 0.89 Ϯ 0.03; Fcell 3 , 0.94 Ϯ 0.06; Fcell 4 , 0.94 Ϯ 0.04; P Ͻ0.01) to maintain a constant red cell mass (2146 Ϯ 460 ml). When ABV was recalculated using PV icg , systemic hematocrit and variable Fcell (ABV Fvariable ), the mean difference between PV icg changes and ABV Fvariable changes, was negligible (Ϫ0.2 Ϯ 35 ml). During intermittent ultrafiltration, RBV changes systematically underestimated the percentage reduction in ABV (mean difference, 7.7 Ϯ 10.6%). When corrected for variations in Fcell, ABV Fvariable and RBV differences were negligible (mean difference 1.2 Ϯ 2.6%). Varying Fcell ratio probably reflects microvascular volume change with net fluid shift from the microcirculation to macrocirculation (intravascular refill). This may result in underestimation of changes in systemic hematocrit and RBV during dialysis such that they were less than those predicted by directly measured changes in plasma volume.Technological advances have allowed the development of devices that can continuously and noninvasively monitor biologic constituents (hematocrit [Hct] and plasma protein concentration) during hemodialysis (HD) treatment. Hct and relative blood density changes online during HD have been advocated as tools for assessing blood volume (BV) changes induced by ultrafiltration (UF) (1). The assumptions that changes in the measured systemic Hct (Hct sys ) result solely from circulating plasma volume (PV) changes induced by UF and that there is uniform mixing of a constant circulating mass of red cells and plasma components in the whole circulation during UF form the basis of such indirect measurements.Attempts to quantify volume shifts precisely in the vascular compartment using relative changes have been difficult as they often underestimate directly measured BV changes (2). Apparent relative BV (RBV) changes therefore cannot be explained by PV depletion alone. Observational studies to analyze the RBV traces or determine the critical Hct for hypotension suggest wide degrees ...

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“…Since these methods were impractical and invasive, todays' devices, which are noninvasive and allowing continuous real-time monitoring of RBV, were invented [92,93]. These new devices either measure hematocrit (Ht) levels by measuring hemoglobin levels using an optic spectroscopic technique [94,95], which is also called Crit-Line method, or by measuring velocity of ultrasonographic waves traveling within the blood, which depends on the concentration of the total blood proteins [92,96]. Both methods give relative changes in the blood volume and usually represented as relative % changes.…”

Section: Blood Volume Monitoringmentioning

confidence: 99%

Effects of Volume Overload and Current Techniques for the Assessment of Fluid Status in Patients with Renal Disease

et al. 2018

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Volume overload is an important, may be the foremost, independent prognostic factor determining the outcome of hemodialysis patients. Therefore, it is crucial to measure fluid status of these patients and avoid volume overload. This review aims to evaluate volume overload, its effects on patients with renal diseases and current methodologies measuring volume status in the body. These techniques will be first classified as clinical evaluation and non-clinical and/or instrumental techniques, which includes biomarkers, ultrasonography, relative blood volume monitoring, bioimpedance, echocardiography, pulmonary artery catheterization, esophageal and/or suprasternal Doppler, and blood viscosity. Advantages and limitations of these different techniques will be reviewed extensively by comparing each other. At last, insights gained from this review can highlight the future prospects in this active area of research.

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Evaluation of an ultrasonic blood volume monitor

Abstract: In summary the blood volume monitor allows precise and reliable measurement of relative blood volume. It provides the instrumentation essential for feedback control of relative blood volume during dialysis.

Cited by 57 publications

References 0 publications

Significance of Interdialytic Weight Gain versus Chronic Volume Overload: Consensus Opinion

Significance of Interdialytic Weight Gain versus Chronic Volume Overload: Consensus Opinion

The Relationship Between Systemic and Whole-Body Hematocrit Is Not Constant during Ultrafiltration on Hemodialysis

Effects of Volume Overload and Current Techniques for the Assessment of Fluid Status in Patients with Renal Disease

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