Kidney Function and Circulatory Collapse. Post-Syncopal Oliguria 1

Brun, Claus; Knudsen, E. O. E.; Raaschou, Flemming

doi:10.1172/jci101739

Cited by 53 publications

(10 citation statements)

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“…Although this may be open to some question, our subjects did not have the circulatory disturbances present in the subjects of Brun, Knudsen, and Raaschou (22,23). In the experiments of Pearce and Newman (19) in which water diuresis was not maximal, a head-up tilt usually produced a greater percentage fall in water excretion than in electrolyte excretion with resultant increase in electrolyte concentration.…”

Section: Discussionmentioning

confidence: 90%

Postural Effects on Renal Tubular Activity 1

Surtshin¹,

White²

1956

J. Clin. Invest.

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A nunber of observers have reported that acute reduction of glomerular filtration rate (GFR) in experimental animals induces a considerable fall in renal excretion of sodium and water. Chronic constriction of one renal artery is followed by persistent fall in salt and water excretion by that kidney (1). In man, change from the recumbent to the erect position is followed by a considerable fall in urinary flow and sodium excretion and by small decrease in inulin and exogenous or endogenous creatinine clearances (2-4). The above findings were on subjects not in maximal water diuresis. In human subjects with a large water load who had been sitting for four to eight hours, change to recumbency was followed by increase in urine flow, sodium excretion and sodium urinary concentration while creatinine U/P ratios fell and endogenous creatinine clearance rose slightly (5).Whether more nearly complete reabsorption of sodium and water following maneuvers reducing GFR is accomplished in the proximal or the distal segment of the tubule is not certain. Pitts and Duggan (6, 7) inferred that organic mercurial diuretics depress the distal reabsorption of sodium, and after observing that aortic constriction produced marked fall in sodium excretion even after administration of a large dose of Mercuhydrin®: in dogs they concluded that the increased sodium and water reabsorption resulting from fall in GFR takes place in the proximal segment. The inference that mercurial diuretics act solely distally has been supported (8) and rejected (9,10) and the loci of the more complete reabsorption remain unidentified.As has been reviewed previously (4) most workers have found a fall in GFR with postural change from the horizontal to a head-up tilt or standing.We here report the effects of postural change on the excretion of water, sodium, creatinine and os- motically active solutes in normal human subjects in maximum water diuresis. We have attempted to localize within the nephron some of the changes observed, using the following assumptions: 1) Distal water reabsorption is abolished in maximum water diuresis with the subject at ease, recumbent or standing (11). 2) Proximal reabsorption is isotonic (12-15). Evidence for the first assumption is that urine flow in maximal water diuresis or in complete diabetes insipidus about equals the volume of fluid leaving the proximal tubules, as estimated by observations on proximal fluid samples obtained by micropuncture (13).If it should be found that the percentage fall in water excretion on changing from recumbency to standing with subjects in maximal water diuresis is significantly greater than the percentage fall in GFR it would follow that the percentage of filtered water reabsorbed proximally is increased on standing. Since proximal reabsorption is considered as isotonic, the percentage of filtered sodium reabsorbed proximally is also increased. If it should further be found that urine and plasma osmolarity remain unchanged, free water clearance also shows a greater percentage fall than does GFR. T...

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Section: Discussionmentioning

confidence: 90%

Postural Effects on Renal Tubular Activity 1

Surtshin¹,

White²

1956

J. Clin. Invest.

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“…Since pituitrin depresses urea clearance in addition to the urine volume, posterior pituitary activity may also play a significant part in the lag in return of kidney function to normal after cessation of pressure breathing (3). That this hormone is involved is suggested by the report of Brun et al (14) who studied kidney function during the circulatory collapse pro-duced by prolonged maintenance of the upright position on the tilt table. They found that the inulin and diodrast clearances were reduced during the period of collapse and for periods of a quarter of an hour or more thereafter.…”

Section: Discussionmentioning

confidence: 95%

The Effects of Continuous Pressure Breathing on Kidney Function 1

Drury¹,

Henry²,

Goodman³

1947

J. Clin. Invest.

104

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Continuous pressure breathing is a technique developed to increase the alveolar oxygen tension by breathing oxygen at higher than ambient pressure. In other words the pressure within the alveoli of the lungs is higher than that outside the chest wall. It is found that as much as 16 mm. Hg of such extra pressure can be tolerated for periods of 30 to 60 minutes by the average healthy man. However, as the extra pressure is increased above this figure, evidence of a deleterious effect upon the circulation becomes increasingly apparent. At pressures of 25 to 40 mm. Hg circulatory collapse and fainting become frequent. Often in cases in which this does not ensue there may develop sensations of impending collapse with pallor and sweating, necessitating termination of the test. Although the blood pressure remains above the control level the pulse is small and difficult to feel and the cardiac output is diminished (1). When using these higher pressures not only is much blood pooled in the veins of the arms and legs but also there is a progressive hemoconcentration due to the passage of fluid from the blood stream into the tissue spaces under .the influence of the raised intravascular pressure (2). A considerable fraction of the total blood volume is thus more or less sequestrated from the general circulation under these conditions and when collapse ensues it is in large part due to decreased effective blood volume. The actual total volume of blood thus isolated cannot be readily assessed and there is need of a reliable but simple test which could be used to assay the impairment of circulation induced by pressure breathing.With this aim in view we studied the blood pressure changes occurring during continuous pressure breathing. This was determined in the usual manner on the arm. Such an approach proved unsatisfactory since a fall in the pressure was usually only observed when the subject was on the verge of syncope. Otherwise the blood pressure was the same as the control value or, as was usual, it was somewhat elevated. We then decided to investigate the value of a determination of the changes in kidney function produced by pressure breathing. METHODThe specific function of the kidney studied was its capacity to excrete urea. This information is obtained by determining the rate of urea excretion during any period and dividing this by the blood urea concentration at the time, thus obtaining a value essentially the same as the kidney clearance. Urea was chosen because of the accuracy with which it can be determined and the constancy of its clearance in a given individual under standard conditions. In addition it has been shown to be responsive to physiological changes in the circulatory system which take place in such conditions as severe exercise (3) and hemorrhage (4). The test was carried out as follows: The subject went without breakfast in the morning and drank a liter of water on rising and 500 ml.

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“…They suggested that constriction of the renal arterioles was produced by some humoral agent following spinal anesthesia. Observations on hemorrhagic shock in man and animal (12,(25)(26)(27), as well as in the post-syncopal state (28), have shown a reduction in renal blood flow and glomerular filtration rate and an increase in renal arterial resistance in most cases where there was a significant drop in the systemic blood pressure accompanied by a drop in the cardiac output.…”

Section: Discussionmentioning

confidence: 99%