An Electrical Method to Determine Hematocrits

Okada, R; Schwan, Herman P.

doi:10.1109/iret-me.1960.5008044

Cited by 33 publications

(15 citation statements)

References 12 publications

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“…In four dogs, electrical resistance in the outflow blood to a 4000 Hz current was measured to assess haematocrit changes (Okada & Schwan, 1960;Devonshire, Nashat & Palmer, 1971) RESULTS All values reported are means + one standard error of mean except where otherwise indicated.…”

Section: Methodsmentioning

confidence: 99%

Responses of abdominal vascular capacitance in the anaesthetized dog to changes in carotid sinus pressure.

Hainsworth¹,

Karim²

1976

The Journal of Physiology

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SUMMARY1. The abdominal circulation of anaesthetized dogs was vascularly isolated without opening the abdomen, by cutting or tying all structures immediately above the diaphragm and tying the proximal ends of the hind limbs. The region was perfused at constant flow through the aorta and drained at constant pressure from the inferior vena cava.2. Vascular resistance responses were expressed as the changes in perfusion pressure and capacitance responses were determined by integrating changes in vena caval outflow.3. Decreasing the pressure in the isolated carotid sinuses over the whole baroreceptor sensitivity range increased mean perfusion pressure from 91 to 149 mmHg (a 67 % increase in resistance) and decreased mean capacitance by 111 ml. (5 ml. kg-').4. The range of carotid sinus pressures over which capacitance responses occurred was at a significantly higher level than the corresponding range for resistance responses.5. Comparison of the reflex responses with the responses to direct stimulation of efferent sympathetic nerves shows that quantitatively similar responses of resistance and capacitance to those induced by a large step decrease in carotid pressure could be produced by stimulating maximally the efferent sympathetic nerves at 5 Hz. These results also suggest that at all levels of carotid sinus pressure there is no difference in the impulse traffic to resistance and capacitance vessels.

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Section: Methodsmentioning

confidence: 99%

Responses of abdominal vascular capacitance in the anaesthetized dog to changes in carotid sinus pressure.

Hainsworth¹,

Karim²

1976

The Journal of Physiology

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“…Or, on the contrary, if the conductivity of each phase is known, the volume fraction of particles can be deduced from the value of the average conductivity. These techniques are frequently used in biomedical applications for instance to determine the hematocrit [1] and are generally known as bioimpedance methods [2]. We could also cite some methods of soils analysis based on the measurement of the effective conductivity [3].…”

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confidence: 99%

How Insulating Particles Increase the Conductivity of a Suspension

2007

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Nonconducting particles suspended in a liquid usually decreases the bulk conductivity since they form obstacles to the ions' migration. However, for sufficiently high dc electric fields, these particles rotate spontaneously (Quincke rotation) and facilitate the ions migration: the effective conductivity of the suspension is thus increased. We present a theoretical analysis and show experimental results which demonstrate that the apparent conductivity of the whole suspension can be higher than that of the suspending liquid.

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“…Ave AVb proportional to AHt and proportional to AVb (GEDDES and BAKER 1967;GEDDES, 1973;GEEDES and KIDDER, 1976;OKADA and SCHWAN, 1960;SAKAMOTO and KANAI, 1979;YAMAKOSHI et al, 1980):…”

Section: Relationship Between the Leg Admittance And The Whole-body Amentioning

confidence: 99%

Electrical admittance method for estimating fluid removal during artificial dialysis

Sakamoto

Kanai

Furuya³

2004

Med. Biol. Eng. Comput.

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Because the conductivity of blood changes remarkably during artificial dialysis, sometimes by more than 20%, changes in tissue admittance at low frequency are caused by changes not only in the extracellular fluid volume but also in blood conductivity. Therefore the changes in blood conductance due to artificial dialysis must be considered for the estimation of water removal by the admittance method. An accurate bio-impedance measurement system was developed. Measurement error was less than 1% at low frequency and 10% at high frequency. A new electrical bio-admittance method (NAM) was evaluated for the continuous measurement of removed fluid volume, using a three parallel-compartment tissue model, consisting of intracellular, interstitial and blood compartments, which takes into account the blood conductivity change. NAM used the equivalent conductivity calculated from the leg admittances of patients, measured at 1 min intervals during various artificial dialysis procedures. The actual amount of excess water removed by ultra-filtration agreed with the NAM-estimated amount within an error of 20%. NAM was also applied to estimate the intra- and extracellular fluid changes. The results were consistent with the physiological changes known to occur during the various forms of dialysis.

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An Electrical Method to Determine Hematocrits

Cited by 33 publications

References 12 publications

Responses of abdominal vascular capacitance in the anaesthetized dog to changes in carotid sinus pressure.

Responses of abdominal vascular capacitance in the anaesthetized dog to changes in carotid sinus pressure.

How Insulating Particles Increase the Conductivity of a Suspension

Electrical admittance method for estimating fluid removal during artificial dialysis

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