Plasma Volume Decrease and Elevated Evans Blue Disappearance Rate in Essential Hypertension

1973 ◽  
Vol 45 (2) ◽  
pp. 173-181 ◽  
Author(s):  
Milos Ulrych
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Essential Hypertension ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Volume ◽  
Evans Blue ◽  
Disappearance Rate ◽  
The Mean ◽  
Volume Decrease

1. The disappearance rate of intravenously injected Evans Blue, plasma volume, cardiac output, and blood pressure were measured in seven normotensive and eighteen hypertensive subjects. 2. Plasma volume was found to be negatively correlated with the mean arterial pressure, Evans Blue disappearance rate and packed cell volume. 3. Faster disappearance rate of Evans Blue in hypertensive subjects may be due to an abnormality of mixing of the label or of the capillaries.

Haemodynamics during Long-Term Thiazide Treatment in Essential Hypertension: Differences between Responders and Non-Responders

1979 ◽  
Vol 57 (s5) ◽  
pp. 359s-362s ◽  
Author(s):  
P. Van Brummelen ◽  
A. Man In 't Veld ◽  
M. A. D. H. Schalekamp
Keyword(s):  
Cardiac Output ◽  
Essential Hypertension ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Volume ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Haemodynamic Effect ◽  
Pronounced Increase

1. Blood pressure, systemic haemodynamics, plasma volume, renin and aldosterone were measured during placebo treatment and after 1, 4 and 12 weeks of hydrochlorothiazide in 13 patients with uncomplicated essential hypertension. Nine of these patients were also studied after 24 and 36 weeks of treatment. 2. Mean arterial pressure was lowered significantly during hydrochlorothiazide treatment. In seven patients the fall in mean arterial pressure was greater than 10% (responders); four of these were studied for 36 weeks. The remainder were considered non-responders. 3. Hydrochlorothiazide lowered cardiac output. The maximal decrease was observed after 12 weeks of treatment (P < 0·01). In responders this was followed by a return to pretreatment values and a significant decrease in total peripheral resistance, whereas in non-responders cardiac output remained reduced and total peripheral resistance was permanently elevated. 4. Changes in plasma volume, renin and aldosterone were not significantly different in responders and non-responders although non-responders tended to show a greater degree of plasma volume depletion and a more pronounced increase in plasma aldosterone. 5. Thus it is unlikely that the initial decrease in cardiac output is an important determinant of the long-term haemodynamic effect of thiazide diuretics.

Solitary Kidney and Ageing as Causes of Low Renin and Aldosterone Concentrations: Relevance to ‘Low-Renin’ Essential Hypertension

1976 ◽  
Vol 51 (s3) ◽  
pp. 177s-180s ◽  
Author(s):  
R. Gordon ◽  
Freda Doran ◽  
M. Thomas ◽  
Frances Thomas ◽  
P. Cheras
Keyword(s):  
Blood Pressure ◽  
Essential Hypertension ◽  
Plasma Renin Activity ◽  
Plasma Volume ◽  
Plasma Renin ◽  
Renin Activity ◽  
Dietary Sodium ◽  
Sodium Restriction ◽  
Normotensive Subjects ◽  
The Mean

1. As experimental models of reduced nephron population in man, (a) twelve men aged 15–32 years who had one kidney removed 1–13 years previously and (b) fourteen normotensive men aged 70–90 years were studied. Results were compared with those in eighteen normotensive men aged 18–28 years and eleven men aged 19–33 years with essential hypertension. 2. While the subjects followed a routine of normal diet and daily activity, measurements were made, after overnight recumbency and in the fasting state, of plasma volume and renin activity on one occasion in hospital and of blood pressure on five to fourteen occasions in the home. Blood pressure was also measured after standing for 2 min and plasma renin activity after 1 h standing, sitting or walking. Twenty-four hour urinary aldosterone excretion was also measured. 3. The measurements were repeated in the normotensive subjects and subjects in (a) and (b) above after 10 days of sodium-restricted diet (40 mmol of sodium/day). 4. The mean plasma renin activity (recumbent) in essential hypertensive subjects was higher than in normotensive subjects. In subjects of (a) and (b) above, it was lower than normotensive subjects, and was not increased by dietary sodium restriction in subjects of (a). 5. The mean aldosterone excretion level was lower in old normotensive subjects than in the other groups, and increased in each group after dietary sodium restriction. 6. Mean plasma volume/surface area was not different between the four groups and in normotensive, essential hypertensive and nephrectomized subjects but not subjects aged 70–90 years was negatively correlated with standing diastolic blood pressure.

Vascular Abnormalities and Pulmonary Hypertension in the Berkeley Sickle Mouse.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3185-3185
Author(s):  
David R. Archer ◽  
Shawn Elms ◽  
Joshua Boutwell ◽  
Jennifer Perry ◽  
Roy Sutliff
Keyword(s):  
Pulmonary Hypertension ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Endothelial Dysfunction ◽  
Mouse Model ◽  
Arterial Pressure ◽  
Right Ventricular ◽  
The Mean

Abstract Clinically, pulmonary hypertension is a major risk factor for mortality in adults with sickle cell disease. Contributing factors probably include red cell hemolysis and vaso-occlusive injury with their associated oxidative and inflammatory stimuli. Previously, we have described RBC hemolysis and endothelial oxidative stress in the Berkeley sickle mouse model and extend those studies in this work to investigate cardiovascular and endothelial dysfunction. Eight to ten month old homozygous and hemizygous Berkeley sickle mice and C57BL/6 control mice were used for all aspects of these experiments. In vivo measurements of mean arterial pressure and right ventricular pressures were conducted in fully anesthetized mice using a pressure transducer inserted in the carotid and right ventricle respectively. Following in vivo readings hearts were excised for measurement of ventricular mass. The ascending aorta was removed and cut into 5 mm rings for in vitro studies of agonist- induced contractility and relaxation. The mean arterial pressure of the hemizygous sickle mice (70.6 ± 3.4) was significantly lower than the control mice (86.0 ± 3.1) and the mean arterial pressure of homozygous sickle mice (59.0 ± 2.2 mmHg) was significantly lower than the hemizygous and control mice (p≤0.05 and p≤0.001, respectively). The right ventricular pressure showed a trend that approached significance (p= 0.08) such that pressures in homozygous mice were ≥ than those in hemizygous which were ≥ than those in control mice. Increased basal cardiac output was suggested by significant left ventricular hypertrophy. In vitro examination of potassium chloride activation of voltage gated calcium channels showed no significant difference in sensitivity or maximal contraction. Similarly, there was no difference in sensitivity to the α1 agonist, phenylephrine. However, both hemi- and homozygous mice showed a significant reduction in maximal force of contraction (normalized to cross sectional area when compared to controls. Maximal acetylcholine induced relaxation of aortic rings was significantly reduced (p≤0.05) in homozygous sickle mice compared to controls. The same effect was not seen with sodium nitroprusside induced relaxation indicating that the acetylcholine effect was not due to effects on the smooth muscle but was endothelium-dependent. The Berkeley mouse model shows cardiac hypertrophy consistent with the increased cardiac output associated with chronic anemia and a reduced basal mean arterial blood pressure similar to that seen in humans. 8–10 month old mice have increased right ventricular pressure and RV mass indicative of pulmonary hypertension. Further endothelial dysfunction is characterized by a reduction in the maximal relaxation elicited by acetylcholine. Therefore, the Berkeley mouse is a good model for investigating sickle related endothelial dysfunction.

The influence of different surgical procedures on hypertension after repair of coarctation

2005 ◽  
Vol 15 (5) ◽  
pp. 477-480 ◽  
Author(s):  
Ugo Giordano ◽  
Salvatore Giannico ◽  
Attilio Turchetta ◽  
Fatma Hammad ◽  
Flaminia Calzolari ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Systolic Blood Pressure ◽  
Diastolic Blood Pressure ◽  
Pulse Pressure ◽  
Ambulatory Monitoring ◽  
Peak Exercise ◽  
End To End

We measured resting and exercise haemodynamics, as well as 24-hour ambulatory blood pressure, so as to study the influence on development of hypertension in children after repair of coarctation by either construction of a subclavian flap or end-to-end anastamosis. The patients in both groups were studied a mean time of 13 years after surgery. Thus, we divided 43 children who had undergone surgical repair of coarctation, and who were not on antihypertensive therapy, into a group of 22 patients who had undergone subclavian flap repair, with a mean age of 14 plus or minus 2.6 years, and another group of 21 patients undergoing end-to-end anastomosis, with a mean age of 13.5 plus or minus 3.9 years. We examined blood pressure at rest and during exercise, along with the measurement of cardiac output using impedance cardiography, and during 24-hour ambulatory monitoring. We recorded systolic and diastolic blood pressures, pulse pressure, cardiac output and total peripheral vascular resistance at rest and at peak exercise. During ambulatory monitoring, we measured mean pressures over 24 hours, in daytime and nighttime, 24-hour pulse pressure, and 24-hour mean arterial pressure. Student's t test was used to judge significance, accepting this when p was less than 0.05. The group repaired using the subclavian flap showed significantly disadvantageous differences for diastolic blood pressure at rest, systolic blood pressure at peak exercise and for 24-hour systolic and diastolic blood pressure, 24-hour mean arterial pressure, and daytime and nighttime systolic blood pressure during ambulatory monitoring. Our findings suggest that, after repair using the subclavian flap in comparison to end-to-end anastomosis, patients show a higher incidence of late hypertension, both during exercise and ambulatory monitoring. The data indicate different residual aortic stiffnesses, these being lower after end-to-end anastomosis, which may be due to the greater resection of the abnormal aortic tissue when coarctation is repaired using the latter technique.

scholarly journals COMPARATIVE CHARACTERISTICS OF THE DYNAMICS OF CARDIOVASCULAR AND RESPIRATORY EFFECTS OF PNEUMOPERITONEUM BASED ON CARBON DIOXIDE AND ARGON IN LAPAROSCOPIC CHOLECYSTECTOMY

2021 ◽  
pp. 90-95
Author(s):  
O. L. Tkachuk ◽  
R. L. Parakhoniak ◽  
S. V. Melnyk ◽  
O. O. Tkachuk-Hryhorchuk
Keyword(s):  
Carbon Dioxide ◽  
Heart Rate ◽  
Cardiac Output ◽  
Laparoscopic Cholecystectomy ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Negative Impact ◽  
Abdominal Pressure ◽  
The Mean ◽  
Respiratory Systems

Pneumoperitoneum is one of the most critical components of laparoscopic surgery, which has a negative effect on gas exchange and stress to circulatory buffering system. One of the top priorities of laparoscopic technologies is to minimize the impact on the respiratory and cardiovascular systems, metabolic dynamics and compensatory abilities of homeostasis. The main goal of this research work is to compare the effects of carboxyperitoneum and argonoperitoneum on the intraoperative dynamics of CO2 concentration as well as cardiovascular and respiratory characteristics in patients undergoing laparoscopic cholecystectomy for various forms of cholelithiasis. Materials and methods. Four experimental groups involved patients based on their nosological form of cholelithiasis and the gas used to induce pneumoperitoneum. All patients underwent laparoscopic cholecystectomy by means of standard procedure. Either medical carbon dioxide or medical argon was used to induce pneumoperitoneum. Intraoperative monitoring of blood carbon dioxide levels PaCO2 was performed by taking venous blood every 15 minutes. Capnometry was performed by means of mainstream analysis using “BIOMED” BM1000C modular patient monitor by recording the discrete values of PetCO2 every 15 minutes, as well as by analyzing photocopies of capnography curves every 15 minutes. Intraoperative echocardiography was performed to identify the mean arterial pressure (MAP), heart rate (HR) and cardiac output (CO) in order to assess the effects of different types of pneumoperitoneum on the cardiovascular system. Results. The obtained data confirm the expected difference in the indices of cardiorespiratory functions between patients with acute cholecystitis and cholelithiasis without signs of inflammation. The investigation revealed that under the influence of pneumoperitoneum, heart rate and mean arterial pressure increase, while the cardiac output decreases. The respiratory pressure marker depends more on the intra-abdominal pressure and presumably the patient’s body type than on the presence of inflammatory syndrome. Argon insufflation has a slight negative impact on the cardiovascular system. Particularly, the mean arterial pressure and heart rate increase, while the cardiac output marker is less decreased as compared to the use of carbon dioxide. Abdominal pressure has a significant effect on the cardiovascular and respiratory systems regardless of the used type of gas. The combination of high intra-abdominal pressure with the elevated head end of the operating table, which is a common practise during cholecystectomy, has especially great influence on cardiovascular and respiratory functions. Operation which is carried out at decreased pressure allows reducing the deviations of practically all indices. Conclusions. Thus, the cardiovascular and respiratory systems adapt under the influence of pneumoperitoneum, providing compensation for the negative effects of mechanical and resorptive-metabolic character. Compensatory-adaptive abilities of the cardiovascular and respiratory systems increase with the decrease of intra-abdominal pressure. The use of argon as a working gas for insufflation into the abdominal cavity during laparoscopy reduces the negative impact of pneumoperitoneum on the cardiovascular and respiratory systems, providing a greater reserve of homeostatic and buffer systems of the body.

scholarly journals Augmented mean arterial pressure supersedes STS-PROM risk score in predicting 1-year mortality in TAVR patients

2021 ◽  
Author(s):  
Chieh-Ju Chao ◽  
Timothy Barry ◽  
Anusha G Shanbhag ◽  
Pradyumma Agasthi ◽  
Amith Seri ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Aortic Valve ◽  
Arterial Pressure ◽  
Risk Score ◽  
Cox Regression ◽  
Cardiac Computed Tomography ◽  
Receiver Operating Curve ◽  
Mortality Data ◽  
The Mean

Abstract Background/Introduction In the era transcatheter aortic valve replacement (TAVR), predicting post-procedural outcome of patients is one of the most important goals in structural heart research. We proposed new parameters (augmented blood pressure) derived from blood pressure and aortic valve gradient measurements and hypothesized that they can predict post-TAVR 1-year mortality. Materials and Methods Patients in the Mayo Clinic National Cardiovascular Diseases Registry (NCDR)-TAVR database who underwent TAVR between January 1, 2014 and June 30, 2017 were identified to retrieve baseline demographics, STS risk score ECG, cardiac computed tomography, echocardiographic and mortality data. Augmented blood pressure parameters and valvulo-arterial impedance were evaluated by Cox regression. After logistic model generation, receiver operating curve analysis was used to assess the model performance against STS risk score. Results The final cohort contains 883 patients. The mean age is 81.3+/-8.5 years old, 58.2% are male. The mean STS risk score is 8.1+/-5.1. The median follow-up duration is 353 days and one-year all-cause mortality rates is 13.3%. Multivariate Cox regression showed that augmented SBP and augmented MAP parameters are independently predictors of 1-year mortality (all p<0.0001). A single-parameter model based on augmented MAP1 supersedes STS risk score in prediction mortality (AUC 0.697 vs. 0.591, p=0.0055). Conclusion Augmented mean arterial pressure provides a simple but effective approach for clinicians to quickly estimate the clinical outcome of TAVR patients and should be incorporated in the assessment of TAVR candidacy.

scholarly journals Mean Blood Pressure and Velocity for Calculation of Ventricular Systolic Work

1998 ◽  
Vol 41 (1) ◽  
pp. 27-28
Author(s):  
Milan Valach
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Diastolic Pressure ◽  
Weighted Average ◽  
Average Pressure ◽  
Mean Pressure ◽  
The Mean ◽  
Definition Of ◽  
Ejection Phase

In physiology, the mean arterial pressure is defined as an average pressure during one or several cardiac cycles. When calculus is not used, the mean pressure is approximately calculated as the diastolic pressure plus one third of the pulse pressure. In this article it is demonstrated that, when ventricular systolic work is concerned, the above definition of mean pressure must be replaced by a weighted average during the ejection phase of the systole. This gives a formula, by which a much higher estimate of the mean pressure is obtained.

What Goes Around Comes Around—Venous Return

2011 ◽  
pp. 48-54
Author(s):  
James R. Munis
Keyword(s):  
Cardiac Output ◽  
Steady State ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Cardiovascular System ◽  
Venous Return ◽  
Atrial Pressure ◽  
Right Atrial ◽  
Interconnected System ◽  
The Mean

By its nature, circulatory physiology is also susceptible to circular reasoning because every part of an interconnected system is affected by, and affects, every other part. If we're not careful, we end up saying things like ‘venous return equals cardiac output’ when, in the steady state, that is true by definition and nothing new is gained. If we grant that right atrial pressure (PRA) is the ‘downstream’ pressure for venous return, then it follows that PRA should be inversely related to venous return (and therefore, to cardiac output). If we simply apply Ohm's law to the cardiovascular system, we forget that the mean arterial pressure not only contributes to venous return but also is sustained by venous return. If venous return fails for any other reason (unrelated to arterial pressure), so too will mean arterial pressure eventually fail.

scholarly journals Comparison between esmolol and verapamil in attenuation of cardiovascular stress response to laryngoscopy and endotracheal intubation in elective surgery

2021 ◽  
Vol 12 (7) ◽  
pp. 64-68
Author(s):  
Nitisha Chakraborty ◽  
Sankar Roy ◽  
Debajyoti Sur ◽  
Arunava Biswas ◽  
Dipasri Bhattacharya ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Weight ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Diastolic Blood Pressure ◽  
Endotracheal Intubation ◽  
Efficacy And Safety ◽  
Cardiovascular Stress ◽  
The Mean

Background: Cardiovascular stress due to reflex sympathetic over activity is a great concern during laryngoscopy and endotracheal intubation. Aims and Objectives: To compare the efficacy and safety of esmolol and verapamil for attenuation of hemodynamic effects (heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure) due to laryngoscopy and endotracheal intubation in elective surgical cases. Materials and Methods: A prospective, randomized, double blinded, controlled study was conducted on 60 patients divided equally into 30 each receiving esmolol (2 mg/kg body weight) and verapamil (0.1 mg/kg body weight) respectively. Heart rate, systolic and diastolic blood pressure and mean arterial pressure were recordedat pre-operative stage, after administration of the study drugs, immediately after intubation and at 1 ,3 ,5 minutes after intubation. Data collected were statistically analyzed. Results: The mean systolic blood pressure was lower in the esmolol group at all times of estimation compared with the verapamil group and the difference was at the time of intubation (p value <0.001).The mean diastolic blood pressure was lower in the esmolol group at all times of estimation compared to the verapamil group which was not statistically significant at any time of estimation. The mean arterial pressure was significantly lower at the time of immediately after intubation (p<0.001) in esmolol as compared to verapamil group. Adverse effects in both the study groups were insignificant. Conclusion: Esmololand Verapamil can effectively attenuate the cardiovascular stress to laryngoscopy and endotracheal intubation with the former appears to be a better alternative from efficacy and safety perspectives.

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