<i>Dynamic Response Characteristics of Systems for Continuous Recording of Concentration Changes in a Flowing Liquid (for Example, Indicator-Dilution Curves)</i>

Fox, Irwin J.; Sutterer, William F.; Wood, Earl H.

doi:10.1152/jappl.1957.11.3.390

Cited by 60 publications

(20 citation statements)

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“…The MTT of each length of sampling system was determined by drawing (at 45.9 ml per minute) undyed blood followed by a "square wave" of dyed blood through the system. The technique was similar to that of Fox, Sutterer, and Wood (10) except that the change in blood sampled was accomplished by rapidly turning a stopcock. The MTT of the sampling systems ranged from 1.6 to 2.0 seconds.…”

Section: Methodsmentioning

confidence: 99%

Reductions in cardiac output, central blood volume, and stroke volume with thermal stress in normal men during exercise.

Rowell¹,

Marx²,

Bruce³

et al. 1966

J. Clin. Invest.

223

164

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Section: Methodsmentioning

confidence: 99%

Reductions in cardiac output, central blood volume, and stroke volume with thermal stress in normal men during exercise.

Rowell¹,

Marx²,

Bruce³

et al. 1966

J. Clin. Invest.

223

164

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“…This avoids mixing and streaming of the dye which occur when long catheters are used between the sampling site and the densitometer. 9 "" A major portion of Results are mean ± SE. SH = sedentary; CH = conditioned.…”

Section: Modification Of the Isolated Heart Preparationmentioning

confidence: 99%

Effects of physical training on end-diastolic volume and myocardial performance of isolated rat hearts.

Bersohn¹,

Scheuer²

1977

Circulation Research

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SUMMARY We studied the performance of ventricular muscle and cardiac function of hearts from rats conditioned by swimming (CH) and from sedentary rats (SH) in an isolated working heart apparatus modified to measure end-diastolic volume by dye dilution. Instantaneous aortic flow, left ventricular (LV) pressure and oxygen consumption were measured. Heart rate and mean aortic pressure were kept constant, and atrial filling pressure was varied from 5 to 20 cm H 2 O. Heart weights of SH and CH were equal and end-diastolic pressures and volumes were similar at all atrial pressures. However, ejection fraction, calculated circumferential fiber velocity, peak systolic pressure, peak aortic flow, cardiac output, and stroke work were all greater in CH than in SH, and the differences increased as atrial pressure was increased. Maximal negative dP/dt was greater in CH than SH at all preloads (P < 0.001). Oxygen consumption of CH was increased in proportion to the increase in work. These results indicate that the improved pumping performance of CH is due to a change in ventricular muscle function. Faster relaxation is a prominent effect of physical training on the rat heart and may foster more complete filling at high heart rates.THE ISOLATED working rat heart apparatus was originally developed by Neely et al. 1 to study cardiac metabolism in a heart performing external work. Performance could be assessed from measurements of left ventricular (LV) and aortic pressures and cardiac output. 1 and from these approximate values for external work could be obtained. However, more precise measurement of the pumping characteristics of the heart (instantaneous flow as well as pressure) was not possible, and the inability to measure ventricular volume precluded making extrapolations to muscle function.The contractile performance of the heart is determined in part by the amount of stretch applied prior to contraction, as governed by the end-diastolic volume. Although end-diastolic pressure could be measured in the isolated working rat heart apparatus, the relation between enddiastolic pressure and volume might vary in different experimental conditions, and a change in this relationship would make alterations in cardiac performance impossible to interpret in terms of muscle function. For instance. Penpargkul and Scheuer 2 showed that cardiac performance was enhanced in hearts from rats subjected to moderate physical conditioning but. in the absence of information about ventricular volumes, it was not known whether the enhanced pumping performance resulted from greater muscle fiber-shortening from the same end-diastolic volume (increased contractility) or from an increased enddiastolic volume due to a change in compliance.This paper reports modifications of the rat heart apparatus so that end-diastolic volume can be determined by a dye-dilution technique and aortic flow can be measured with an electromagnetic flowmeter. From these data, ejection fraction, ventricular volume, peak values and first derivatives of pressure and flow, external ...

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“…The characteristics of the photocells, light source, and electronics as well as the design of the cuvette lumen must be taken into consideration in order to achieve optimal light transmission and maximum frequency response [7]. However, as it is the primary purpose of this review to acquaint the reader with a knowledge of nonspecific effects, emphasis will be placed only on the design considerations directly relating to undesired optical signals, namely consideration of proper choice of optical filter wavebands.…”

Section: Some Optical Design Considerations For Jvons~ecific Rejectionmentioning

confidence: 99%

“…This was due both to the increased dynamic response of these systems [7] and to the use of monochromatic densitometers. Some method had to be devised to compensate for the nonspecific effects and still maintain insensitivity to oxygen saturation.…”

Section: An Approach To Compensation For Nonspecific Effects With Carmentioning

confidence: 99%

Optical Artifacts in Whole Blood Densitometry: A Review of Undesirable Optical Signals, Nonspecific Effects, Encountered during Measurements of Oxygen Saturation and Dye Dilution Curves by Light Transmission

Sutterer¹

1967

Pediatr Res

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Dynamic Response Characteristics of Systems for Continuous Recording of Concentration Changes in a Flowing Liquid (for Example, Indicator-Dilution Curves)

Cited by 60 publications

References 0 publications

Reductions in cardiac output, central blood volume, and stroke volume with thermal stress in normal men during exercise.

Reductions in cardiac output, central blood volume, and stroke volume with thermal stress in normal men during exercise.

Effects of physical training on end-diastolic volume and myocardial performance of isolated rat hearts.

Optical Artifacts in Whole Blood Densitometry: A Review of Undesirable Optical Signals, Nonspecific Effects, Encountered during Measurements of Oxygen Saturation and Dye Dilution Curves by Light Transmission

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