scholarly journals Functional MRI with magnetization transfer effects: Determination of BOLD and arterial blood volume changes

2008 ◽  
Vol 60 (6) ◽  
pp. 1518-1523 ◽  
Author(s):  
Tae Kim ◽  
Kristy Hendrich ◽  
Seong-Gi Kim
Keyword(s):  
Functional Mri ◽  
Blood Volume ◽  
Magnetization Transfer ◽  
Transfer Effects ◽  
Volume Changes ◽  
Arterial Blood ◽  
Arterial Blood Volume

Reflection photoplethysmography of arterial-blood-volume pulses

1977 ◽  
Vol 15 (1) ◽  
pp. 22-31 ◽  
Author(s):  
J. Weinman ◽  
A. Hayat ◽  
G. Raviv
Keyword(s):  
Blood Volume ◽  
Arterial Blood ◽  
Arterial Blood Volume

scholarly journals The VEGF gene polymorphism impacts brain volume and arterial blood volume

2017 ◽  
Author(s):  
Hikaru Takeuchi ◽  
Hiroaki Tomita ◽  
Yasuyuki Taki ◽  
Yoshie Kikuchi ◽  
Chiaki Ono ◽  
...  
Keyword(s):  
Gene Polymorphism ◽  
Blood Volume ◽  
Brain Volume ◽  
Vegf Gene ◽  
Arterial Blood ◽  
Arterial Blood Volume ◽  
Vegf Gene Polymorphism

Detection of early central circulatory transits in patients with cirrhosis by gamma variate fit of indicator dilution profiles

2005 ◽  
Vol 288 (4) ◽  
pp. G677-G684 ◽  
Author(s):  
Jens H. Henriksen ◽  
Søren Møller ◽  
Stefan Fuglsang ◽  
Flemming Bendtsen
Keyword(s):  
Cardiac Output ◽  
Blood Volume ◽  
Indicator Dilution ◽  
Arterial Oxygen ◽  
Dilution Method ◽  
Gamma Variate ◽  
Arterial Blood ◽  
Flow Circulation ◽  
Cirrhotic Patients

Patients with cirrhosis have hyperdynamic circulation with abnormally distributed blood volume and widespread arteriovenous communications. We aimed to detect possible very early (i.e., before 4 s) and early (i.e., after 4 s) central circulatory transits and their potential influence on determination of central and arterial blood volume (CBV). Thirty-six cirrhotic patients and nineteen controls without liver disease undergoing hemodynamic catheterization were given central bolus injections of albumin with different labels. Exponential and gamma variate fits were applied to the indicator dilution curves, and the relations between flow, circulation times, and volumes were established according to kinetic principles. No significant very early central circulatory transits were identified. In contrast, early (i.e., 4 s to maximal) transits corresponding to a mean of 5.1% (vs. 0.8% in controls; P < 0.005) of cardiac output (equivalent to 0.36 vs. 0.05 l/min; P < 0.01) were found in cirrhotic patients. These early transits averaged 7.7 vs. 12.7 and 17.2 s of ordinary central transits of cirrhotic patients and controls, respectively ( P < 0.001). Early transits were directly correlated to the alveolar-arterial oxygen difference in the cirrhotic patients ( r = 0.46, P < 0.01) but not in controls ( r = 0.04; not significant). There was good agreement between the CBV determined by the conventional indicator dilution method and that determined by separation of early and ordinary transits by the gamma variate fit method (1.51 vs. 1.53 liter; not significant). In conclusion, no very early central circulatory transits were identified in cirrhotic patients. A significant part of the cardiac output undergoes an early transit, probably through pulmonary shunts or areas with low ventilation-perfusion ratios in cirrhotic patients. Composite determination of CBV by the gamma variate fit method is in close agreement with established kinetic methods. The study provides further evidence of abnormal central circulation in cirrhosis.

scholarly journals Observations on changes in the blood pressure and blood volume following operations in man. (Preliminary communication.)

1919 ◽  
Vol 90 (632) ◽  
pp. 415-437 ◽  
Keyword(s):  
Blood Pressure ◽  
Blood Volume ◽  
Capillary Blood ◽  
Volume Changes ◽  
Auscultatory Method ◽  
Blood Pressures ◽  
Preliminary Communication ◽  
Haemoglobin Content

The cases here investigated were wounded men undergoing operations, and repeated examinations were usually made. Most of the cases showed only slight symptoms of shock. Methods .—The systolic and diastolic blood pressures were measured before, during, and after operations, a Riva Rocci apparatus being used. The auscultatory method recommended by Oliver was used to determine the two levels. The hæmoglobin was estimated also, as far as possible, at the same time. The actual level of the hæmoglobin value was read by Haldane’s method, while the changes in any patient were determined by comparison of the different samples in a Du Borscq colourimeter. For this purpose suspensions of the corpuscles in a dilution of 1 in 200 in saline were used, the volume chosen being 10 c. c., and these samples were hæmolysed with saponin before being read in the colourimeter. For this method I am indebted to Prof. Dreyer, and it has proved more accurate than any other. The blood has been taken always from either the ear or the finger. In estimating the blood volume changes from these readings, it has been assumed that the blood volume varies inversely as the hæmoglobin percentage. During and after operations this will be only relatively true, since hæmorrhage occurs. The amount of blood lost may, however, be roughly estimated by the loss of hæmoglobin in the first 24 hours after operation. In cases of slight shock, equilibrium will probably have been reached in this time. That this is true is indicated by the results obtained and put forward in Case I. In this patient a fair amount of blood was lost during the process of decompression for a fractured skull, and nearly all the blood lost was washed into buckets by a stream of saline running over the wound. The saline in these buckets was collected after the operation and the hæmoglobin content was determined by reading the contents in the Du Borscq colourimeter against a sample of the patient’s own blood, taken before operation. In this way it was calculated that he lost 782 c. c. of blood. By the determination of the change in the hæmoglobin value in 24 hours, it was estimated that he lost 17⋅7 per cent, of his blood volume, and this was reckoned (taking Dreyer’s formula for blood volume) to correspond to a loss of 760 c. c. The agreement was therefore remarkable, and it is probable that the methods are moderately accurate. In all the Tables the calculations of blood volume are made neglecting this factor of hæmorrhage. At the bottom of the Tables the estimated blood lost is given, and in the last column of the Tables corrected values for the blood volume are given in which the hæmorrhage has been approximately allowed for. The results obtained seemed to indicate that the changes in the hæmoglobin percentage of capillary blood do demonstrate the changes seen in the blood volume, provided that the lag due to a slow circulation and partial stasis is allowed for, the hæmoglobin changes following those in the blood pressure.

scholarly journals Pathogenesis and Treatment of Refractory Oedema in Nephrotic Syndrome

EMJ Urology ◽  
2021 ◽  
pp. 107-117
Author(s):  
Priyanka Jethwani ◽  
Namrata Krishnan
Keyword(s):  
Clinical Trials ◽  
Nephrotic Syndrome ◽  
Blood Volume ◽  
Loop Diuretics ◽  
Primary Role ◽  
Sodium Retention ◽  
Oedema Formation ◽  
Arterial Blood ◽  
Filtration Barrier ◽  
Arterial Blood Volume

Oedema is a hallmark feature of nephrotic syndrome (NS) and can cause significant patient morbidity. The pathogenesis of oedema formation is complex and results from abnormalities in sodium retention, inter-play of neurohormonal factors, and changes in capillary filtration barrier. Salt retention is often primary (‘overfill’ theory) because of increased sodium-potassium adenosine triphosphatase activity in the collecting duct cells, increased direct epithelial sodium channel activation (ENaC) by urinary proteases (independent of aldosterone), and an overall increased effective arterial blood volume. However, a subset of patients with NS, especially children, demonstrate decreased effective arterial blood volume (‘underfill’ theory) and secondary sodium retention as the primary mechanism of oedema formation. Increased capillary permeability and vascular inflammation contributes as well. Loop diuretics with or without salt-poor albumin are the mainstay of therapy in adults, although no large clinical trials exist to guide diuretic choice or dosage. Combination diuretic therapy is recommended to achieve multi-site nephron blockade and overcome diuretic resistance, which is a frequent challenge. Use of direct ENaC inhibitors (amiloride) in combination with loop diuretics may be especially beneficial given the primary role of ENaC in sodium retention. Aquaretics such as vasopressin receptor antagonists may have a role in treatment as well. Well-designed clinical trials are essential to guide therapy of refractory oedema in NS. In this review, the authors discuss the pathogenesis of oedema formation in patients with NS and propose a treatment algorithm for management of resistant oedema based on the limited available evidence.

scholarly journals Similarities and Differences in Arterial Responses to Hypercapnia and Visual Stimulation

2010 ◽  
Vol 31 (2) ◽  
pp. 560-571 ◽  
Author(s):  
Yi-Ching Lynn Ho ◽  
Esben Thade Petersen ◽  
Ivan Zimine ◽  
Xavier Golay
Keyword(s):  
Blood Volume ◽  
Transit Time ◽  
Gray Matter ◽  
Visual Stimulation ◽  
Vascular System ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen Level ◽  
Functional Studies ◽  
Arterial Blood ◽  
Arterial Blood Volume

Despite the different origins of cerebrovascular activity induced by neurogenic and nonneurogenic conditions, a standard assumption in functional studies is that the consequence on the vascular system will be mechanically similar. Using a recently developed arterial spin labeling method, we examined arterial blood volume, arterial-microvascular transit time, and cerebral blood flow (CBF) in the gray matter and in areas with large arterial vessels under hypercapnia, visual stimulation, and a combination of the two. Spatial heterogeneity in arterial reactivity was observed between conditions. During hypercapnia, large arterial volume changes contributed to CBF increase and further downstream, there were reductions in the gray matter transit time. These changes were not significant during visual stimulation, and during the combined condition they were moderated. These findings suggest distinct vascular mechanisms for large and small arterial segments that may be condition specific. However, the power relationships between gray matter arterial blood volume and CBF in hypercapnia (α = 0.69 ± 0.24) and visual stimulation (α = 0.68 ± 0.20) were similar. Assuming consistent capillary and venous volume responses across these conditions, these results offer support for a consistent total CBV–flow relationship typically assumed in blood oxygen-level dependent calibration techniques.

scholarly journals Correlation between arterial blood volume obtained by arterial spin labelling and cerebral blood volume in intracranial tumours

2011 ◽  
Vol 24 (4) ◽  
pp. 211-223 ◽  
Author(s):  
Danielle van Westen ◽  
Esben T. Petersen ◽  
Ronnie Wirestam ◽  
Roger Siemund ◽  
Karin Markenroth Bloch ◽  
...  
Keyword(s):  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Arterial Spin Labelling ◽  
Intracranial Tumours ◽  
Arterial Blood ◽  
Arterial Blood Volume ◽  
Spin Labelling
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