Further evidence for the unimportance of renal autoregulation

1961 ◽  
Vol 201 (3) ◽  
pp. 495-498 ◽  
Author(s):  
Jimmy B. Langston ◽  
Arthur C. Guyton ◽  
C. C. Hull ◽  
G. G. Armstrong
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Renal Circulation ◽  
Pressure Flow ◽  
Renal Autoregulation ◽  
Blood Flows ◽  
Mild Degree ◽  
Pressure Axis ◽  
Pressure Flow Study ◽  
Flow Study

Previous experiments from this laboratory indicated that normal kidneys may not have significant intrinsic ability to autoregulate their blood flow when renal arterial pressure is varied. However, in these earlier studies, the renal blood flow was less than that generally accepted as normal, and there was a possibility that the renal circulation had not been completely isolated. This could have resulted in extrarenal blood flow during the pressure-flow study. In the present experiments, renal blood flows were in the normal range at all pressure levels. This difference was achieved by rendering the animals areflex prior to the laparotomy. The pressure-flow relationship was studied under these conditions, and the resulting curves were slightly concave to the pressure axis in the lower pressure range, indicating only a mild degree of autoregulation, approximately the same degree as that found in other tissues. However, the renal blood flow still increased rapidly with each increase in perfusion pressure even in the range of so-called autoregulation. It was also shown that all the blood that passed through the perfusion system also passed through the kidney, eliminating the possibility of extrarenal blood flow.

Effect of pentobarbital and hemorrhage on renal autoregulation

1985 ◽  
Vol 249 (3) ◽  
pp. F356-F360
Author(s):  
P. C. Kremser ◽  
B. L. Gewertz
Keyword(s):  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Renal Blood Flow ◽  
Lower Limit ◽  
Conscious State ◽  
Pressure Flow ◽  
Renal Autoregulation ◽  
Pentobarbital Anesthesia ◽  
Arterial Hemorrhage

Renal blood flow and hemodynamic autoregulation were assessed in seven chronically instrumented canines studied in the conscious state and after pentobarbital anesthesia administration (30 mg/kg). The effects of acute arterial hemorrhage (10 and 15 ml/kg) were also studied. In the conscious state, no significant changes in autoregulation were observed following 10 mg/kg hemorrhage. With pentobarbital and 10 ml/kg hemorrhage, a significant change in the limits of autoregulation was noted (autoregulatory limit 78.5 +/- 16.6 vs. 88.4 +/- 25.3 mmHg, P less than 0.05). Four animals were also studied in the conscious state following 15 ml/kg acute arterial hemorrhage. In these animals, mean arterial pressure decreased (from 105.0 +/- 11.4 to 87.8 +/- 7.2 mmHg, P less than 0.025) but renal blood flow (from 293 +/- 38 to 272 +/- 65 ml/min) and autoregulatory limit did not change. We conclude that renal blood flow is unaffected by hemorrhage or pentobarbital alone. In the conscious state, renal pressure-flow autoregulation is maintained despite moderate hemorrhage and systemic hypotension. The lower limit of autoregulation is significantly changed by even minor hemorrhage in the pentobarbital-anesthetized state.

scholarly journals Correlation between penile cuff test and pressure-flow study in patients candidates for trans-urethral resection of prostate

BMC Urology ◽  
2014 ◽  
Vol 14 (1) ◽  
Author(s):  
Daniele Bianchi ◽  
Angelo Di Santo ◽  
Gabriele Gaziev ◽  
Roberto Miano ◽  
Stefania Musco ◽  
...  
Keyword(s):  
Pressure Flow ◽  
Pressure Flow Study ◽  
Flow Study

scholarly journals The Role of Urodynamic Investigations in Management of Stress Urinary Incontinence

2015 ◽  
Vol 61 (4) ◽  
pp. 298-302
Author(s):  
Veronica Maria Ghirca ◽  
D Porav-Hodade ◽  
C Chibelean ◽  
S Voidazan ◽  
M Vartolomei ◽  
...  
Keyword(s):  
Urinary Incontinence ◽  
Surgical Treatment ◽  
Stress Urinary Incontinence ◽  
Abdominal Pressure ◽  
Detrusor Contraction ◽  
Pressure Flow ◽  
Detrusor Contractility ◽  
Urodynamic Investigations ◽  
Pressure Flow Study ◽  
Flow Study

AbstractObjective: The aim of this study is to establish the importance of urodynamic investigations in women diagnosed with stress urinary incontinence (SUI) who have indication of surgical treatment.Methods: We performed a retrospective study over a period of 3 years (January 2012-December 2014) in Clinic of Urology from Tirgu Mures. The inclusion criteria were: female patients diagnosed with SUI having indication of surgical treatment and the existence of urodynamic investigations (uroflowmetry and pressure-flow study). We evaluated 118 patients with SUI. From this patients, 24 cases (20.3%) accomplished the criteria from above.Results: We included in this study 24 patients aged 64.25+/−8.25 (standard deviation). Pressure-flow study revealed an impaired detrusor contraction in 13 cases. Statistical anaysis pouved a relation between existence of post void residual urine (PVR) and underactive detrusor (UD) (p=0.01). There is no correlation between maximum flow rate (Qmax) and UD, r=0.18 (CI= −0.2-0.5), p=0.3 and between normal value of Qmax and normal detrusor pressure (Pdet), r= 0,28(CI=−0.6-0.8), p=0.58. Also there is no relation between a low Qmax and UD, p=0,5. There is a statistical relation between increased abdominal pressure (Pabd) and UD, p=0.02.Conclusions: Uroflowmetry has the role to guide us concerning the micturition process Pressure-flow study is indicated in management of SUI, in selected cases, in patients with voiding symptomatology, the suspicion of a detrusor contractility dysfunction, abnormal uroflowmetry results, existence of PVR, in prediction of the surgical treatment outcome or if we think that the findings can change the choice of treatment.

scholarly journals PRESSURE-FLOW STUDY AFTER PERCUTANEOUS NEPHROLITHOTRYPSY

1989 ◽  
Vol 80 (9) ◽  
pp. 1351-1356
Author(s):  
Naoki Kura ◽  
Takumi Yamada ◽  
Yukio Kageyama ◽  
Takeharu Negishi ◽  
Takehisa Ushiyama
Keyword(s):  
Pressure Flow ◽  
Pressure Flow Study ◽  
Flow Study

PRESSURE FLOW STUDY DATA IN A GROUP OF ASYMPTOMATIC MALE CONTROL PATIENTS 45 YEARS OLD OR OLDER

2001 ◽  
Vol 165 (2) ◽  
pp. 683-687 ◽  
Author(s):  
R.M.H. WALKER ◽  
G. ROMANO ◽  
A.H. DAVIES ◽  
N.A. THEODOROU ◽  
R.G. SPRINGALL ◽  
...  
Keyword(s):  
Study Data ◽  
Pressure Flow ◽  
Male Control ◽  
Pressure Flow Study ◽  
Flow Study

Patterns urodinamici in pazienti con prostatodinia

1995 ◽  
Vol 62 (4) ◽  
pp. 611-613
Author(s):  
M. Vella ◽  
G. Camilleri ◽  
D. Dl Trapani ◽  
M. Lamartina ◽  
M. Pavone-Macaluso
Keyword(s):  
Therapeutic Management ◽  
Pressure Flow ◽  
Pressure Flow Study ◽  
Flow Study

The Authors report their experience on 24 patients with prostatodynia. The Adynamic alterations, which occur in most cases, show the usefulness of cystomanometry and pressure-flow study for providing a better nosological picture and therapeutic management.

scholarly journals Quantification of conversion and degradation of circulating angiotensin in rats

1999 ◽  
Vol 277 (2) ◽  
pp. R412-R418 ◽  
Author(s):  
Johannes Bauer ◽  
Heike Berthold ◽  
Franz Schaefer ◽  
Heimo Ehmke ◽  
Niranjan Parekh
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Systemic Circulation ◽  
Left Renal Artery ◽  
Minor Importance ◽  
Ang Ii ◽  
Renal Circulation ◽  
Degradation Rates ◽  
Measured Change

The aim of the present study was to quantify with a uniform technique the rates of conversion of ANG I to ANG II in the lung and kidney and the degradation of both peptides to biologically inactive products in the pulmonary, renal, and systemic circulation. We infused the peptides intravenously, into the left ventricle, and into the left renal artery of rats and compared their effects on renal blood flow. The measured change in renal blood flow was used as a bioassay parameter to estimate the concentration of circulating ANG II. Mathematical analysis of our data allowed us to calculate conversion and degradation rates. Furthermore, the role of aminopeptidases A (EC 3.4.11.7 ) and N (EC 3.4.11.2 ) in the degradation of the peptides in the kidney was investigated by intrarenal infusion of the inhibitor amastatin. Our results show that the conversion rate of ANG I is 75% in the pulmonary and 21% in the renal circulation. Both peptides are degraded by 5% in the pulmonary, by 67% in the systemic, and by 93% in the renal circulation. Amastatin prevented 60% of the renal degradation of the peptides to inactive products, and this effect could be attributed to inhibition of aminopeptidase N. The results indicate that the converting capacity of the kidney is of minor importance for endocrine generation of ANG II but could be useful for the paracrine production.

Hepatic arterial and portal venous pressure-flow relationships in isolated, perfused liver

1962 ◽  
Vol 202 (6) ◽  
pp. 1090-1094 ◽  
Author(s):  
Robert E. Condon ◽  
Niles D. Chapman ◽  
Lloyd M. Nyhus ◽  
Henry N. Harkins
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Portal Vein ◽  
Venous Pressure ◽  
Perfused Liver ◽  
Perfusion Rate ◽  
Flow Curves ◽  
Pressure Flow ◽  
Pressure Axis ◽  
Blood Pressure Responses

Blood pressure responses to alteration in blood flow were studied in the completely isolated, excised liver of the calf during perfusion of the hepatic artery or portal vein. The pressure-flow curves in both of the afferent vessels of the liver are curvilinear, with concavity toward the pressure axis. Resistance increases progressively with increases in perfusion rate; resistance increases are proportionately of greater magnitude than the increases in blood flow demonstrating autoregulation in both hepatic arterial and portal venous systems. The autoregulatory nature of pressure-flow responses is not affected by prolonged perfusion or marked acidosis.

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