Failure of acute saralasin to reverse chronic hypertension in fetal lambs

1991 ◽  
Vol 260 (4) ◽  
pp. R811-R816
Author(s):  
D. F. Anderson ◽  
N. D. Binder
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Upper Body ◽  
Chronic Hypertension ◽  
Aortic Blood Flow ◽  
Flow Reduction ◽  
Arterial Blood ◽  
Aortic Blood ◽  
Blood Flow Reduction

Upper body arterial hypertension developed in 12 fetal lambs after chronic suprarenal aortic blood flow reduction. Sixty minutes after blood flow reduction, intravenous saralasin infusion was able to reduce upper body mean arterial blood pressure to control levels. Although saralasin infusion was able to decrease upper body arterial blood pressure after 1 day of hypertension, it was not able to return blood pressure to control levels. Three or more days later, saralasin was unable to cause a significant reduction in upper body arterial blood pressure. We conclude that, although the renin-angiotensin system has a role in maintaining the elevated blood pressure after greater than or equal to 1 day of suprarenal aortic blood flow reduction, some other mechanism also participates. We have ruled out a role for changing blood volume, and our results suggest that an elevation of plasma catecholamines is not responsible. Some other pathway for fluid regulation available to the fetus may be responsible.

scholarly journals Estimation of changes in instantaneous aortic blood flow by the analysis of arterial blood pressure

2012 ◽  
Vol 112 (11) ◽  
pp. 1832-1838 ◽  
Author(s):  
Tatsuya Arai ◽  
Kichang Lee ◽  
Robert P. Marini ◽  
Richard J. Cohen
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Arterial Blood Pressure ◽  
Aortic Blood Flow ◽  
Windkessel Model ◽  
Arx Model ◽  
Arterial Blood ◽  
Aortic Blood

The purpose of this study was to introduce and validate a new algorithm to estimate instantaneous aortic blood flow (ABF) by mathematical analysis of arterial blood pressure (ABP) waveforms. The algorithm is based on an autoregressive with exogenous input (ARX) model. We applied this algorithm to diastolic ABP waveforms to estimate the autoregressive model coefficients by requiring the estimated diastolic flow to be zero. The algorithm incorporating the coefficients was then applied to the entire ABP signal to estimate ABF. The algorithm was applied to six Yorkshire swine data sets over a wide range of physiological conditions for validation. Quantitative measures of waveform shape (standard deviation, skewness, and kurtosis), as well as stroke volume and cardiac output from the estimated ABF, were computed. Values of these measures were compared with those obtained from ABF waveforms recorded using a Transonic aortic flow probe placed around the aortic root. The estimation errors were compared with those obtained using a windkessel model. The ARX model algorithm achieved significantly lower errors in the waveform measures, stroke volume, and cardiac output than those obtained using the windkessel model ( P < 0.05).

Hepatosplanchnic Vasoregulation and Oxygen Consumption During Selective Aortic Blood Flow Reduction and Reperfusion

2011 ◽  
Vol 171 (2) ◽  
pp. 532-539 ◽  
Author(s):  
Ruy J. Cruz ◽  
Alejandra G. Garrido ◽  
Décio de Natale Caly ◽  
Mauricio Rocha-e-Silva
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Aortic Blood Flow ◽  
Flow Reduction ◽  
Aortic Blood ◽  
Blood Flow Reduction

scholarly journals Changes in regional blood flow and pCO2 gradients during isolated abdominal aortic blood flow reduction

2003 ◽  
Vol 29 (12) ◽  
pp. 2255-2265 ◽  
Author(s):  
Rafael Knuesel ◽  
Stephan M. Jakob ◽  
Lukas Brander ◽  
Hendrik Bracht ◽  
Andreas Siegenthaler ◽  
...  
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Aortic Blood Flow ◽  
Flow Reduction ◽  
Aortic Blood ◽  
Blood Flow Reduction ◽  
Abdominal Aortic

scholarly journals Organs Blood Flow during Elevation of Body Temperature in Sevoflurane Anesthetized Rats

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Koichi Shimo ◽  
Ko Takakura ◽  
Kenji Shigemi
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Body Temperature ◽  
Arterial Blood Pressure ◽  
Pulse Rate ◽  
Organ Blood Flow ◽  
Aortic Blood Flow ◽  
Sevoflurane Anesthesia ◽  
Arterial Blood ◽  
Small Intestinal

The aim of this study is to investigate how elevation of body temperature changes organs blood flow during sevoflurane anesthesia. We conducted in vivo research on 14 male Wistar rats to monitor pulse rate and arterial blood pressure and measure hepatic, small intestinal, renal, and descending aortic blood flow using a laser Doppler blood flowmeter. We assessed the changes in organ blood flow, pulse rate, and arterial blood pressure during elevation of the rats’ body temperatures up to 41.5°C under anesthesia with 2.0% or 3.0% sevoflurane. We concluded that elevation of body temperature up to 39.5°C does not change hepatic, small intestinal, and renal blood flow during 2.0 and 3.0% sevoflurane anesthesia.

Arterial pressure after chronic reductions in suprarenal aortic flow in fetal lambs

1987 ◽  
Vol 253 (4) ◽  
pp. H838-H844
Author(s):  
D. F. Anderson ◽  
C. M. Parks ◽  
J. J. Faber
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Arterial Blood Pressure ◽  
Plasma Renin ◽  
Aortic Flow ◽  
Renin Activity ◽  
Upper Body ◽  
Aortic Blood Flow ◽  
Arterial Blood

Experiments were performed on 13 fetal lambs of 126 days gestational age. Seven days after surgery, suprarenal aortic blood flow was reduced to 70% of control with an inflatable occluder for a period of at least 4 days. This produced an almost constant aortic pressure difference of 35 mmHg across the occluder. Plasma renin activity (PRA) rose in the next hour from 6 to 42 ng.ml-1.h-1 (P less than 0.01) but decreased to a level that was statistically insignificantly above normal by the next day. PRA as a function of lower body arterial blood pressure showed rapid adaptation. Upper body arterial blood pressure was statistically significantly elevated by 5 mmHg within 5 min and continued to rise while plasma renin activity was falling. Femoral artery blood pressure dropped immediately but returned to near normal within 1 h and remained there. The long-term upper body hypertension was irreversible with a 30-min infusion of saralasin. Subrenal aortic flow reduction caused none of these changes. We conclude that the fetal kidneys can regulate arterial blood pressure upward but that the long-term effect does not depend solely on a direct vasoconstrictive action of angiotensin.

The relationship of blood flow velocity fluctuations to intracranial pressure B waves

1992 ◽  
Vol 76 (3) ◽  
pp. 415-421 ◽  
Author(s):  
David W. Newell ◽  
Rune Aaslid ◽  
Renate Stooss ◽  
Hans J. Reulen
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Intracranial Pressure ◽  
Arterial Blood Pressure ◽  
Wave Amplitude ◽  
Transcranial Doppler Ultrasound ◽  
Normal Subjects ◽  
Content Type ◽  
Arterial Blood ◽  
Flow Fluctuations

✓ Intracranial pressure (ICP) and continuous transcranial Doppler ultrasound signals were monitored in 20 head-injured patients and simultaneous synchronous fluctuations of middle cerebral artery (MCA) velocity and B waves of the ICP were observed. Continuous simultaneous monitoring of MCA velocity, ICP, arterial blood pressure, and expired CO2 revealed that both velocity waves and B waves occurred despite a constant CO2 concentration in ventilated patients and were usually not accompanied by fluctuations in the arterial blood pressure. Additional recordings from the extracranial carotid artery during the ICP B waves revealed similar synchronous fluctuations in the velocity of this artery, strongly supporting the hypothesis that blood flow fluctuations produce the velocity waves. The ratio between ICP wave amplitude and velocity wave amplitude was highly correlated to the ICP (r = 0.81, p < 0.001). Velocity waves of similar characteristics and frequency, but usually of shorter duration, were observed in seven of 10 normal subjects in whom MCA velocity was recorded for 1 hour. The findings in this report strongly suggest that B waves in the ICP are a secondary effect of vasomotor waves, producing cerebral blood flow fluctuations that become amplified in the ICP tracing, in states of reduced intracranial compliance.

Forearm and finger blood flow responses to passive body tilts

1979 ◽  
Vol 46 (2) ◽  
pp. 288-292 ◽  
Author(s):  
Y. A. Mengesha ◽  
G. H. Bell
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Pulse Rate ◽  
Forearm Blood Flow ◽  
Body Tilt ◽  
Finger Blood Flow ◽  
Arterial Blood ◽  
Forearm Vascular Resistance

Ten to fifteen healthy subjects, ages 18--30 yr, were used to assess the correlation of forearm blood flow with graded passive body tilts and vascular resistance and also to discern the relative effects of body tilts on finger blood flow. In the head-up tilts forearm blood flow and arterial blood pressure fell progressively, whereas forearm vascular resistance and pulse rate increased. In the head-down tilts the forearm blood flow and the arterial blood pressure increased, whereas the forearm vascular resistance and pulse rate decreased. These changes were found to be significantly correlated with the different tilt angles and with one another. In a preliminary study it was found that infrared heating of the carpometacarpal region produced finger vasodilatation similar to the forearm vasodilatation observed by Crockford and Hellon (6). However, unlike forearm blood flow, finger blood flow showed no appreciable response to either the head-up or head-down tilts. This indicates that the sympathetic tone and the volume of blood in the finger are not appreciably altered by this test procedure at least 1 min after the body tilt is assumed.

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