Biomaterial Database

Evaluation of an ultrasonic blood volume monitor. 1998

C Johner, and P W Chamney, and D Schneditz, and M Krämer

Fresenius Medical Care, Innovation and Technology, Bad Homburg, Germany.

BACKGROUND Hypotension complicates approximately 30% of all dialysis treatments. Although the genesis of hypotension is multifactorial, hypovolaemia is thought to play a major role as a direct result of decreased blood volume, particularly during ultrafiltration. The described blood volume monitor enables blood volume to be measured continuously by a non-invasive technique. METHODS The blood volume monitor is based on the principle that the total protein concentration, the sum of haemoglobin and plasma proteins in the vascular space, changes during ultrafiltration. Changes of total protein concentration are determined from the velocity of sound waves in blood, measured using a cuvette in the extracorporeal circuit designed for this purpose. The precision of the blood volume monitor was evaluated in 180 dialysis treatments in 49 patients. The relative blood volume obtained by the monitor was compared with a standard reference method involving calculation of relative blood volume from serial measurements of haemoglobin. RESULTS A very good agreement between the two methods was achieved (SD = 1.70%, r > 0.96). The results showed no sensitivity to changes in serum sodium concentration (range 130-145 mmol). The 'noise' introduced in the blood volume signal was low (< or = 0.2%, sampling rate 10 s) allowing subtle blood volume changes to be detected with high resolution. In addition the device enabled the measurement of haematocrit (Hct) and haemoglobin (Hb) to be made since this is the largest blood component determining total protein concentration. A comparison with the centrifuge method revealed an accuracy of +/-2.9 Hct-%, and a comparison with the photometer an accuracy of +/-0.8 g Hb/dl. CONCLUSIONS 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.

UI	MeSH Term	Description	Entries
D007676	Kidney Failure, Chronic	The end-stage of CHRONIC RENAL INSUFFICIENCY. It is characterized by the severe irreversible kidney damage (as measured by the level of PROTEINURIA) and the reduction in GLOMERULAR FILTRATION RATE to less than 15 ml per min (Kidney Foundation: Kidney Disease Outcome Quality Initiative, 2002). These patients generally require HEMODIALYSIS or KIDNEY TRANSPLANTATION.	ESRD,End-Stage Renal Disease,Renal Disease, End-Stage,Renal Failure, Chronic,Renal Failure, End-Stage,Chronic Kidney Failure,End-Stage Kidney Disease,Chronic Renal Failure,Disease, End-Stage Kidney,Disease, End-Stage Renal,End Stage Kidney Disease,End Stage Renal Disease,End-Stage Renal Failure,Kidney Disease, End-Stage,Renal Disease, End Stage,Renal Failure, End Stage
D008297	Male		Males
D001810	Blood Volume	Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.	Blood Volumes,Volume, Blood,Volumes, Blood
D004867	Equipment Design	Methods and patterns of fabricating machines and related hardware.	Design, Equipment,Device Design,Medical Device Design,Design, Medical Device,Designs, Medical Device,Device Design, Medical,Device Designs, Medical,Medical Device Designs,Design, Device,Designs, Device,Designs, Equipment,Device Designs,Equipment Designs
D005069	Evaluation Studies as Topic	Works about studies that determine the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies.	Critique,Evaluation Indexes,Evaluation Methodology,Evaluation Report,Evaluation Research,Methodology, Evaluation,Pre-Post Tests,Qualitative Evaluation,Quantitative Evaluation,Theoretical Effectiveness,Use-Effectiveness,Critiques,Effectiveness, Theoretical,Evaluation Methodologies,Evaluation Reports,Evaluation, Qualitative,Evaluation, Quantitative,Evaluations, Qualitative,Evaluations, Quantitative,Indexes, Evaluation,Methodologies, Evaluation,Pre Post Tests,Pre-Post Test,Qualitative Evaluations,Quantitative Evaluations,Report, Evaluation,Reports, Evaluation,Research, Evaluation,Test, Pre-Post,Tests, Pre-Post,Use Effectiveness
D005260	Female		Females
D006400	Hematocrit	The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.	Erythrocyte Volume, Packed,Packed Red-Cell Volume,Erythrocyte Volumes, Packed,Hematocrits,Packed Erythrocyte Volume,Packed Erythrocyte Volumes,Packed Red Cell Volume,Packed Red-Cell Volumes,Red-Cell Volume, Packed,Red-Cell Volumes, Packed,Volume, Packed Erythrocyte,Volume, Packed Red-Cell,Volumes, Packed Erythrocyte,Volumes, Packed Red-Cell
D006435	Renal Dialysis	Therapy for the insufficient cleansing of the BLOOD by the kidneys based on dialysis and including hemodialysis, PERITONEAL DIALYSIS, and HEMODIAFILTRATION.	Dialysis, Extracorporeal,Dialysis, Renal,Extracorporeal Dialysis,Hemodialysis,Dialyses, Extracorporeal,Dialyses, Renal,Extracorporeal Dialyses,Hemodialyses,Renal Dialyses
D006454	Hemoglobins	The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.	Eryhem,Ferrous Hemoglobin,Hemoglobin,Hemoglobin, Ferrous
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man