scholarly journals Effect of spontaneous breathing on umbilical venous blood flow and placental transfusion during delayed cord clamping in preterm lambs

2019 ◽  
Vol 105 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Emma Brouwer ◽  
Arjan B te Pas ◽  
Graeme R Polglase ◽  
Erin V McGillick ◽  
Stefan Böhringer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Body Weight ◽  
Spontaneous Breathing ◽  
Venous Blood ◽  
Vena Cava ◽  
Venous Blood Flow ◽  
Delayed Cord Clamping ◽  
Venous Flow ◽  
Cord Clamping ◽  
Pregnant Sheep

IntroductionDuring delayed umbilical cord clamping, the factors underpinning placental transfusion remain unknown. We hypothesised that reductions in thoracic pressure during inspiration would enhance placental transfusion in spontaneously breathing preterm lambs.ObjectiveInvestigate the effect of spontaneous breathing on umbilical venous flow and body weight in preterm lambs.MethodsPregnant sheep were instrumented at 132–133 days gestational age to measure fetal common umbilical venous, pulmonary and cerebral blood flows as well as arterial and intrapleural (IP) pressures. At delivery, doxapram and caffeine were administered to promote breathing. Lamb body weights were measured continuously and breathing was assessed by IP pressure changes.ResultsIn 6 lambs, 491 out of 1117 breaths were analysed for change in body weight. Weight increased in 46.6% and decreased in 47.5% of breaths. An overall mean increase of 0.02±2.5 g per breath was calculated, and no net placental transfusion was observed prior to cord clamping (median difference in body weight 52.3 [−54.9–166.1] g, p=0.418). Umbilical venous (UV) flow transiently decreased with each inspiration, and in some cases ceased, before UV flow normalised during expiration. The reduction in UV flow was positively correlated with the standardised reduction in (IP) pressure, increasing by 109 mL/min for every SD reduction in IP pressure. Thus, the reduction in UV flow was closely related to inspiratory depth.ConclusionsSpontaneous breathing had no net effect on body weight in preterm lambs at birth. UV blood flow decreased as inspiratory effort increased, possibly due to constriction of the inferior vena cava caused by diaphragmatic contraction, as previously observed in human fetuses.

Blood flow in the ovary and adjacent structures of the non-pregnant sheep

1983 ◽  
Vol 103 (2) ◽  
pp. 259-265 ◽  
Author(s):  
P. O. Janson ◽  
D. Williams ◽  
O. M. Petrucco ◽  
F. Amato ◽  
R. F. Seamark ◽  
...  
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Vascular Pedicle ◽  
Venous Flow ◽  
Adjacent Structures ◽  
Pregnant Sheep ◽  
Rapid Changes ◽  
Capillary Bed

Abstract. Blood flow to the ovary, vascular pedicle and oviduct was measured in anaesthetized non-cycling and cycling ewes by timed collection of ovarian venous blood. The degree of arterio-venous shunting across the ovary and pedicle was estimated both in vivo and in vitro by perfusing the tissues with 15 ± 5 μm radioactive microspheres. The mean ovarian blood flow in non-cycling animals was 1.9 ml/min, which was 51% of blood flow in the ovarian vein. In cycling animals ovarian blood flow at midcycle was 2.9 ml/min (66% of ovarian venous flow) in non-luteal ovaries and 4.3 ml/min (79% of venous flow) in luteal ovaries. The degree of arterio-venous shunting was low in all stages of the cycle (1.0–2.6% across ovary + pedicle). The degree of shunting was also found to be very small in vitro (0.007–1.38%) in both non-luteal and luteal ovaries. A considerable number of microspheres was entrapped in the vascular pedicle of the ovary indicating the presence of an extensive capillary bed. There was an inverse relationship between blood flow in the ovary and flow in the vascular pedicle. Alterations in distribution of blood flow between the ovary and adjacent structures supplied by the ovarian artery may be of functional significance in allowing rapid changes in ovarian blood flow. The results of the present study indicate that changes in ovarian blood flow during the oestrous cycle are not caused by an action on arteriovenous shunt vessels.

scholarly journals SURGICAL ANATOMY OF VENOUS BLOOD FLOW OF THE I NFERIOR VENA CAVA SYSTEM

2021 ◽  
pp. 17-22
Author(s):  
V. I. Rusin ◽  
S. O. Boyko ◽  
V. V. Rusin ◽  
S. Sh. S. Boyko
Keyword(s):  
Blood Flow ◽  
Average Length ◽  
Venous Blood ◽  
Vena Cava ◽  
Anatomical Study ◽  
Surgical Anatomy ◽  
Hepatic Veins ◽  
Common Trunk ◽  
Clinical Anatomy ◽  
Venous Blood Flow

Summary. Purpose. Conduct an anatomical examination of the inferior vena cava (IVC) and its branches and determine the paths of collateral venous blood flow. Materials and methods. An anatomical examination of the IVC and its branches was performed on 27 corpses as a result of autopsy. The bodies of the corpses were hypostenic-normosthenic type. The organ complex was eviscerated by the Shore method. The degree of IVC coverage by the liver in relation to the circumference of the IVC was determined. Measurements of the total length of the IVC and for each of the individual 6 segments of the IVC were performed. The hepatic and lumbar veins were studied and the paths of collateral venous blood flow were analyzed. Results and discussion. The average length of IVC in the infrarenal segment was 107.6 mm, in the retrohepatic — 59.3 mm, in the suprarenal — 26.2 mm, in the interrenal — 23.4 mm, in the infradiaphragm — 15.2 mm, in the supradiaphragm — 12.0 mm, along the entire subdiaphragm segment — 197.8 mm. The coverage of IVC by the liver by 1/2 of its circumference was detected in 13 (48.1 %), by 2/3 — in 11 (40.7 %), by 1/3 — in 2 (7.4 %), by the whole length – in 1 (3.7 %) cases. Up to 23 venous trunks flow into the retrohepatic part of the IVC. The avascular area is located under the main hepatic veins with an average length of 13.1 mm and under the right renal vein with an average length of 17.8 mm. In 92.6 % of cases, the lumbar veins had an odd nature of confluence with the IVC – one common trunk. Conclusions: The anatomical study presented new knowledge of the clinical anatomy of IVС branches.

scholarly journals Effect of breathing on venous return during delayed cord clamping: an observational study

2021 ◽  
pp. fetalneonatal-2020-321431
Author(s):  
Emma Brouwer ◽  
Ronny Knol ◽  
Annie Kroushev ◽  
Thomas Van Den Akker ◽  
Stuart B Hooper ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Right Atrium ◽  
Spontaneous Breathing ◽  
Venous Return ◽  
Vena Cava ◽  
Ductus Venosus ◽  
Delayed Cord Clamping ◽  
Cord Clamping ◽  
Digital Format ◽  
The Right

ObjectiveTo investigate the effect of spontaneous breathing on venous return in term infants during delayed cord clamping at birth.MethodsEchocardiographic ultrasound recordings were obtained directly after birth in healthy term-born infants. A subcostal view was used to obtain an optimal view of the inferior vena cava (IVC) entering the right atrium, including both the ductus venosus (DV) and the hepatic vein (HV). Colour Doppler was used to assess flow direction and flow velocity. Recordings continued until the umbilical cord was clamped and were stored in digital format for offline analyses.ResultsUltrasound recordings were obtained in 15 infants, with a median (IQR) gestational age of 39.6 (39.0–40.9) weeks and a birth weight of 3560 (3195–4205) g. Flow was observed to be antegrade in the DV and HV in 98% and 82% of inspirations, respectively, with flow velocity increasing in 74% of inspirations. Retrograde flow in the DV was observed sporadically and only occurred during expiration. Collapse of the IVC occurred during 58% of inspirations and all occurred caudal to the DV inlet (100%).ConclusionSpontaneous breathing was associated with collapse of the IVC and increased antegrade DV and HV flow velocity during inspiration. Therefore, inspiration appears to preferentially direct blood flow from the DV into the right atrium. This indicates that inspiration could be a factor driving placental transfusion in infants.

scholarly journals Arterio-Venous Branchial Blood Flow in the Atlantic Cod Gadus Morhua

1992 ◽  
Vol 165 (1) ◽  
pp. 73-84 ◽  
Author(s):  
LENA SUNDIN ◽  
STEFAN NILSSON
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Atlantic Cod ◽  
Vascular System ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
Venous Flow ◽  
Flow Measurements ◽  
Vasomotor Function

We have estimated the branchial venous blood flow in the Atlantic cod by direct single-crystal Doppler blood flow measurements in vivo. In the undisturbed animal, this flow amounts to 1.7 ml min−1 kg−1, which corresponds to about 8 % of the cardiac output. Studies of both an isolated perfused gill apparatus in situ and simultaneous measurements of cardiac output and branchial venous flow in vivo were made to assess the effects of some putative vasoregulatory substances. Adrenaline dilates the arterio-arterial pathway and constricts the arterio-venous pathway, thus decreasing branchial venous drainage. 5-Hydroxytryptamine (5-HT), in contrast, produced marked vasoconstriction in the arterio-arterial pathway of the branchial vasculature, increasing the branchial venous blood flow. Cholecystokinin-8 (CCK-8) and caerulein produced similar cardiovascular effects, with marked constriction of both arterio-arterial and arterio-venous pathways. The study demonstrates the ability of the vascular system of the gills to regulate the distribution of branchial blood flow, and summarizes the vasomotor effects of some substances with possible vasomotor function in the cod gills.

H2S contributes to the hepatic arterial buffer response and mediates vasorelaxation of the hepatic artery via activation of KATP channels

2008 ◽  
Vol 295 (6) ◽  
pp. G1266-G1273 ◽  
Author(s):  
Nikolai Siebert ◽  
Daniel Cantré ◽  
Christian Eipel ◽  
Brigitte Vollmar
Keyword(s):  
Blood Flow ◽  
Portal Vein ◽  
Hepatic Artery ◽  
Buffer Capacity ◽  
Venous Blood ◽  
Control Level ◽  
Vena Cava ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Arterial Blood

Hepatic blood supply is uniquely regulated by the hepatic arterial buffer response (HABR), counteracting alterations of portal venous blood flow by flow changes of the hepatic artery. Hydrogen sulfide (H2S) has been recognized as a novel signaling molecule with vasoactive properties. However, the contribution of H2S in mediating the HABR is not yet studied. In pentobarbital-anesthetized and laparotomized rats, flow probes around the portal vein and hepatic artery allowed for assessment of the portal venous (PVBF) and hepatic arterial blood flow (HABF) under baseline conditions and stepwise reduction of PVBF for induction of HABR. Animals received either the H2S donor Na2S, DL-propargylglycine as inhibitor of the H2S synthesizing enzyme cystathionine-γ-lyase (CSE), or saline alone. Additionally, animals were treated with Na2S and the ATP-sensitive potassium channel (KATP) inhibitor glibenclamide or with glibenclamide alone. Na2S markedly increased the buffer capacity to 27.4 ± 3.0% ( P < 0.05 vs. controls: 15.5 ± 1.7%), whereas blockade of H2S formation by DL-propargylglycine significantly reduced the buffer capacity (8.5 ± 1.4%). Glibenclamide completely reversed the H2S-induced increase of buffer capacity to the control level. By means of RT-PCR, Western blot analysis, and immunohistochemistry, we observed the expression of both H2S synthesizing enzymes (CSE and cystathionine-β-synthase) in aorta, vena cava, hepatic artery, and portal vein, as well as in hepatic parenchymal tissue. Terminal branches of the hepatic afferent vessels expressed only CSE. We show for the first time that CSE-derived H2S contributes to HABR and partly mediates vasorelaxation of the hepatic artery via activation of KATP channels.

scholarly journals VENOUS BLOOD INDICES AFTER CAVAPLICATION IN PATIENTS WITH THROMBOSIS OF THE VENA CAVA INFERIOR

2020 ◽  
pp. 143-147
Author(s):  
V. I. Rusin ◽  
Ya. M. Popovich
Keyword(s):  
Blood Flow ◽  
Inferior Vena Cava ◽  
Inferior Vena ◽  
Venous Blood ◽  
Vena Cava ◽  
Volume Index ◽  
Venous Blood Flow ◽  
Vena Cava Inferior ◽  
Systolic Volume ◽  
Before And After

Summary. Despite reports of plication with inferior vena cava thrombosis, the venous hemodynamics before and after hardware cavaplication has been not evaluated. The aim of research. Estimate the changes of the venous blood flow indices after complication in patients with vena cava inferior thrombosis. Materials and methods. Quantitative assessment of venous blood flow was performed in 34 patients with inferior vena cava thrombosis before and after incomplete hardware cavaplication. Cavaplication was performed in 11 (32.4 %) patients with non-tumor and in 23 (67.6 %) patients with tumors of the vena cava inferior. For selecting the site of cavaplication, the infrarenal branch of the vena cava inferior directly below the renal veins was prevailed – in 29 (85.3 %) patients, the plication of vena cava inferior lower or higher hepatic veins in 4 (11.8 %) and 1 (2.9 %) patients were performed respectively. Results. Increases of following indices of central and regional hemodynamics after hardware cavaplication were observed, in particular, volume (by 56.5 %) and the linear rate of blood flow (by 40.4 %), minute volume of blood flow (by 16.2 %), cardiac index (by 8.8 %), systolic volume (by 6 %), end-systolic volume index (by 4.5 %), end-diastolic volume index (by 3.9 %) and ejection fraction (by 2.1 %). Instead, the pressure in the inferior vena cava (by 18.2 %) and stroke volume (by 8.9 %) decreased, which, however, was also considered as a positive result of thrombectomy from the vena cava inferior and hardware cavaplication. Conclusions. Within a year after inferior vena plication, indicators of central and peripheral hemodynamics were within the physiological norm and collateral pathways during radioisotope phleboscintigraphy weren`t determined. At the same time, the lumen of the vena cava inferior was completely restored, after 12-18 months, in all cases after plication.

Norethynodrel with mestranol and venous blood flow

JAMA ◽  
1966 ◽  
Vol 198 (7) ◽  
pp. 784-785 ◽  
Author(s):  
A. Neistadt
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Venous Blood Flow
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