Arteriovenous Blood Research Articles

Spontaneous resolution of low-flow spinal arteriovenous fistulas.

Spinal vascular anomalies with arteriovenous blood shunting include spinal arteriovenous malformations (SAVMs) and spinal arteriovenous fistulas (SAVFs), which are distinguished by the presence or absence of an interposed nidus. SAVFs can be further characterized based on their location (perimedullary, dural, or extradural) and flow pattern (high-flow versus low-flow shunts). The spontaneous resolution of a spinal vascular malformation, i.e., the complete disappearance-in the absence of therapeutic measures-of a lesion previously identified by angiography, seems to represent an exceptional phenomenon. This study retrospectively analyzed seven patients with spontaneously resolving spinal vascular malformations observed by the senior author between January 2008 and April 2017. A total of 143 spinal vascular malformations were angiographically evaluated during the considered time period, including nine spontaneously resolving SAVFs in six patients, seven spinal epidural fistulas, and two spinal dural arteriovenous fistula. The "spontaneous" resolution of spinal vascular malformations appears to selectively involve SAVFs. While vessel wall alterations previously documented on the venous side of SAVFs may play an important role in the regression of these lesions, angiography seems to represent a significant contributing factor, probably through the prothrombotic properties of nonionic contrast agents.

High adventure shunts old notions of pulmonary vascular control during hypoxic exercise: contrasting views that might just burst your bubble!

High adventure shunts old notions of pulmonary vascular control during hypoxic exercise: contrasting views that might just burst your bubble!

Protective effect of micro needle array drug delivery technology on the blood vessel of arteriovenous fistula

Objective To investigate the protective effect of mucopolysaccharide polysulfate cream(MPC) and micro needle array drug delivery technologarray(MNADDT) on the blood vessel of arteriovenous fistula. Methods Eighty cases maintenance hemodialysis patients with autogenous arteriovenous fistula were randomly divided into control group(with the treatment of MPC) and study group(with the treatment of MPC plus MNADDT), 40 patients in each group.Both groups were studied for the duration of 12 months.The vascular complications of puncture pain sense, puncture failure times, phlebitis, hardening of the arteries, internal fistula stenosis or embolism, pseudoaneurysm, swollen hands comprehensive syndrome of two groups were observed, and the changes of arteriovenous fistula blood flow, blood vessel diameter by Doppler ultrasound were observed in the two groups for 12 months. Results (1)The incidence of puncture pain(2.71±0.11 vs.2.76±0.14, t=2.21, P<0.05), puncture failure times(38 times vs.73 times, χ2=11.425, P<0.05), phlebitis(2 cases vs.8 cases, χ2=4.341, P<0.05) and blood vessel sclerosis(2 cases vs.9 cases, χ2=5.446, P<0.05) of the treatment group were significantly lower than that of the control group during the study(P<0.05). (2)Blood flow of arteriovenous fistulain of control group before and after treatment were (859.7±148.3) ml/min and ( 946.5±169.2) ml/min respectively, and the difference was significant(t=2.356, P<0.05). While blood flow of arteriovenous fistulain, cephalic vein diameter, head of venous flow velocity of study group before and after treatment were (824.6±171.5 ) ml/min and ( 1 218.1±241.9) ml/min, (5.59±0.74) mm and (6.02±0.57) mm, (94.23±27.35) cm/s and (115.85±36.63) cm/s, respectively, and the differences were significant(t=8.212, 2.382, 2.877, P<0.05), there were no significantly changes in the above indexes in the study group after treatment(t=5.3612, 2.152, 2.281, P<0.05). Conclusion MPC plus MNADDT can reduce the vascular complications of arteriovenous fistula, improve blood vessel diameter and increase blood flow. Key words: Hemodialysis; Arteriovenous fistula; Complication; Micro needle array administration; Doppler ultrasound

Effect of therapeutic hypercapnia on cerebral oxygen metabolism in patients undergoing thoracoscopic surgery in beach chair position

Objective To evaluate the effect of therapeutic hypercapnia on cerebral oxygen metabolism in the patients undergoing thoracoscopic surgery in beach chair position (BCP). Methods Sixty patients of both sexes, aged 18-32 yr, with body mass index of 19-24 kg/m2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, scheduled for elective bilateral thoracic sympathectomy performed via a thoracoscope, were divided into control group (group C) and hypercapnia group (group H), with 30 patients in each group using a random number table.After induction of anesthesia, all the patients in both groups were tracheally intubated and mechanically ventilated using the ventilation regimen low tidal volume intermittent positive pressure ventilation combined with low level of positive end-expiratory pressure (5 cmH2O), maintaining arterial carbon dioxide partial pressure (PaCO2) at 35-45 mmHg.PaCO2 was maintained at 45-55 mmHg by adjusting the respiratory rate after the patients were placed in BCP in group H. Anesthesia was maintained with target-controlled infusion of propofol and intermittent intravenous boluses of rocuronium and sufentanil.Bispectral index value was maintained at 45-55.Before anesthesia induction (baseline), at 5 min after intubation, and at 5, 10, 15 and 20 min after the patients were placed in BCP, blood samples were taken from the radial artery and jugular bulb for blood gas analysis, jugular venous bulb oxygen saturation was measured, and arteriovenous blood O2 content difference, cerebral O2 extraction rate, and venous to arterial blood lactate concentration difference were calculated. Results Compared with group C, PaCO2 and jugular venous bulb oxygen saturation were significantly increased, and arteriovenous blood O2 content difference and cerebral O2 extraction rate were significantly decreased at at 5, 10, 15 and 20 min after the patients were placed in BCP in group H (P 0.05). Conclusion Therapeutic hypercapnia can improve the cerebral oxygen metabolism in the patients undergoing thoracoscopic surgery in BCP. Key words: Hypercapnia; Posture; Oxygen consumption; Brain

Arteriovenous blood gas agreement in intensive care patients with varying levels of circulatory compromise

Arteriovenous blood gas agreement in intensive care patients with varying levels of circulatory compromise

Arteriovenous blood gas agreement in intensive care patients with varying levels of circulatory compromise

Arteriovenous blood gas agreement in intensive care patients with varying levels of circulatory compromise

Computer Simulations of the Tumor Vasculature: Applications to Interstitial Fluid Flow, Drug Delivery, and Oxygen Supply.

Tumor vasculature, the blood vessel network supplying a growing tumor with nutrients such as oxygen or glucose, is in many respects different from the hierarchically organized arterio-venous blood vessel network in normal tissues. Angiogenesis (the formation of new blood vessels), vessel cooption (the integration of existing blood vessels into the tumor vasculature), and vessel regression remodel the healthy vascular network into a tumor-specific vasculature. Integrative models, based on detailed experimental data and physical laws, implement, in silico, the complex interplay of molecular pathways, cell proliferation, migration, and death, tissue microenvironment, mechanical and hydrodynamic forces, and the fine structure of the host tissue vasculature. With the help of computer simulations high-precision information about blood flow patterns, interstitial fluid flow, drug distribution, oxygen and nutrient distribution can be obtained and a plethora of therapeutic protocols can be tested before clinical trials. This chapter provides an overview over the current status of computer simulations of vascular remodeling during tumor growth including interstitial fluid flow, drug delivery, and oxygen supply within the tumor. The model predictions are compared with experimental and clinical data and a number of longstanding physiological paradigms about tumor vasculature and intratumoral solute transport are critically scrutinized.

Arterio-venous differences in cord levels of catecholamines, glucose, lactate and blood gases.

Norepinephrine (NE) and epinephrine (EPI) levels are higher in cord arterial blood relative to venous blood, consistent with active mechanisms of placental-maternal clearance. There are no contemporary studies of cord arteriovenous blood levels of sulfated and non-sulfated catechols. To assess the arteriovenous differences in cord blood levels of dopamine (DA), the sulfated catecholamines and their sulfated and non-sulfated metabolites. To correlate levels of oxygen, H+/CO2, and glucose with cord catecholamine levels. Fifty-seven term infants, delivered by elective cesarean section, were recruited. Cord arterial and venous blood was sampled; levels of glucose, lactate, blood gases, six catechols and their sulfated conjugates were measured. With one exception (DOPA sulfate), mean cord arterial levels of sulfated and non-sulfated catechols were significantly higher than venous levels. Arterial lactate and glucose levels were independently associated with NE levels, but only lactate was associated with levels of EPI and DA. This study establishes that in vivo metabolic parameters of hypoxia, respiratory and metabolic acidosis are associated with catecholamine levels, a key relationship for perinatal adaptation and homeostasis, and findings that are consistent with in vitro studies of the regulators of catecholamine secretion.

Arteriovenous blood gas agreement in intensive care patients with varying levels of circulatory compromise: a pilot study

Arteriovenous blood gas agreement in intensive care patients with varying levels of circulatory compromise: a pilot study

Gut and sublingual microvascular effect of esmolol during septic shock in a porcine model.

IntroductionEsmolol may efficiently reduce heart rate (HR) and decrease mortality during septic shock. An improvement of microcirculation dissociated from its macrocirculatory effect may a role. The present study investigated the effect of esmolol on gut and sublingual microcirculation in a resuscitated piglet model of septic shock.MethodsFourteen piglets, anesthetized and mechanically ventilated, received a suspension of live Pseudomonas aeruginosa. They were randomly assigned to two groups: the esmolol (E) group received an infusion of esmolol, started at 7.5 μg⋅kg−1⋅min−1, and progressively increased to achieve a HR below 90 beats⋅min−1. The control (C) group received an infusion of Ringer’s lactate solution. HR, mean arterial pressure (MAP), cardiac index (CI), stroke index (SI), systemic vascular resistance (SVR), arterio-venous blood gas and lactate were recorded. Oxygen consumption (VO2), delivery (DO2) and peripheral extraction (O2ER) were computed. Following an ileostomy, a laser Doppler probe was applied on ileal mucosa to monitor gut microcirculatory laser Doppler flow (GMLDF). Videomicroscopy was also used on ileal mucosa and sublingual areas to evaluate mean flow index (MFI), heterogeneity, ratio of perfused villi and proportion of perfused vessels. Resuscitation maneuvers were performed following a defined algorithm.ResultsBacterial infusion induced a significant alteration of the gut microcirculation with an increase in HR. Esmolol produced a significant time/group effect with a decrease in HR (P <0.004) and an increase in SVR (P <0.004). Time/group effect was not significant for CI and MAP, but there was a clear trend toward a decrease in CI and MAP in the E group. Time/group effect was not significant for SI, O2ER, DO2, VO2, GMLDF and lactate. A significant time/group effect of ileal microcirculation was found with a lower ileal villi perfusion (P <0.025) in the C group, and a trend toward a better MFI in the E group. No difference between both groups was found regarding microcirculatory parameters in the sublingual area.ConclusionsEsmolol provided a maintenance of microcirculation during sepsis despite its negative effects on macrocirculation. Some parameters even showed a trend toward an improvement of the microcirculation in the gut area in the esmolol group.

Renal glucose release during hypoglycemia is partly controlled by sympathetic nerves - a study in pigs with unilateral surgically denervated kidneys.

Catecholamines are known to increase renal glucose release during hypoglycemia. The specific extent of the contribution of different sources of catecholamines, endocrine delivery via circulation or release from autonomous sympathetic renal nerves, though, is unknown. We tested the hypothesis that sympathetic renal innervation plays a major role in the regulation of renal gluconeogenesis. For this purpose, instrumented adolescent pigs had one kidney surgically denervated while the other kidney served as a control. A hypoglycemic clamp with arterial blood glucose below 2 mmol/L was maintained for 75 min. Arteriovenous blood glucose difference, inulin clearance, p-aminohippurate clearance, and sodium excretion were measured in intervals of 15 min separately for both kidneys. Blood glucose was lowered to 0.84 ± 0.33 mmol/L for 75 min. The side-dependent renal net glucose release (SGN) decreased significantly after the unilateral ablation of renal nerves. In the linear mixed model, renal denervation had a significant inhibitory effect on renal net glucose release (P = 0.036). The SGN of the ablated kidney decreased by 0.02 mmol/min and was equivalent to 43.3 ± 23.2% of the control (nonablated) kidney in the pigs. This allows the conclusion that renal glucose release is partly controlled by sympathetic nerves. This may be relevant in humans as well, and could explain the increased risk of severe hypoglycemia of patients with diabetes mellitus and autonomous neuropathy. The effects of denervation on renal glucose metabolism should be critically taken into account when considering renal denervation as a therapy in diabetic patients.

NUMERICAL SIMULATION OF THE EFFECT OF VENOUS NEEDLE'S FLOW RATE AND ANGLE ON FLOW PARAMETERS OF A HEMODIALYSIS GRAFT

Arterio-Venous grafts, which are used for hemodialysis, frequently develop intimal hyperplasia in venous anastomosis which ultimately leads to graft failure. It is observed in different studies that the wall shear stress can be correlated to intimal hyperplasia development. Although high Arterio-Venous access blood flow has been implicated in the pathogenesis of graft stenosis, the role of needle's angle and flow rate during the hemodialysis procedure are relatively unexplored. Since the flow field in the region of the venous needle may be a source of damage, in the current study, a numerical investigation of the effect of venous needle's angle and flow rate on hemodynamic parameters of the flow inside a hemodialysis graft has been carried out. Five cases of different needle angles and flow rates with graft flow rate of 500 ml/min have been investigated. Results indicate that in lower angle and lower flow rates the risk of damage is less because of lower wall shear stress and more uniform shear stress distribution on graft wall.

Accessing to arteriovenous blood flow dynamics response using combined laser speckle contrast imaging and skin optical clearing.

Laser speckle contrast imaging (LSCI) shows a great potential for monitoring blood flow, but the spatial resolution suffers from the scattering of tissue. Here, we demonstrate the capability of a combination method of LSCI and skin optical clearing to describe in detail the dynamic response of cutaneous vasculature to vasoactive noradrenaline injection. Moreover, the superior resolution, contrast and sensitivity make it possible to rebuild arteries-veins separation and quantitatively assess the blood flow dynamical changes in terms of flow velocity and vascular diameter at single artery or vein level.

Integrative models of vascular remodeling during tumor growth.

Malignant solid tumors recruit the blood vessel network of the host tissue for nutrient supply, continuous growth, and gain of metastatic potential. Angiogenesis (the formation of new blood vessels), vessel cooption (the integration of existing blood vessels into the tumor vasculature), and vessel regression remodel the healthy vascular network into a tumor-specific vasculature that is in many respects different from the hierarchically organized arterio-venous blood vessel network of the host tissues. Integrative models based on detailed experimental data and physical laws implement in silico the complex interplay of molecular pathways, cell proliferation, migration, and death, tissue microenvironment, mechanical and hydrodynamic forces, and the fine structure of the host tissue vasculature. With the help of computer simulations high-precision information about blood flow patterns, interstitial fluid flow, drug distribution, oxygen and nutrient distribution can be obtained and a plethora of therapeutic protocols can be tested before clinical trials. In this review, we give an overview over the current status of integrative models describing tumor growth, vascular remodeling, blood and interstitial fluid flow, drug delivery, and concomitant transformations of the microenvironment. © 2015 The Authors. WIREs Systems Biology and Medicine published by Wiley Periodicals, Inc.

フロープロファイル法およびパルスドプラ法による上腕動脈推定血流量と超音波希釈法によるarteriovenous fistula (AVF) 血流量との比較

われわれは濃度希釈法による動静脈瘻 (AVF) 推定血流量 (eAVF-FV) と, フロープロファイル法 (FP法) およびパルスドプラ法 (PD法) による上腕動脈推定血流量 (eBA-FV) の測定値を比較検討した. 維持血液透析17例に対し透析前にアロカメディカル社ProSoundα7 (以下A7), GEヘルスケア社LOGIQ Book XP (以下LB) により, eBA-FVおよびAVF血流途絶下のAVF側eBA-FV (pBA-FV), AVF反対側肢のeBA-FV (cBA-FV) を, さらに透析中Transonic Systems社HD02により濃度希釈法でeAVF-FVを各3回測定し, 再現性, 平均値, 誤差率 (誤差率=[|eBA-FV-eAVF-FV|]/eAVF-FV×100) を検討した. eAVF-FVは155～1,045mL/min (566±322mL/min) でA7-FP法とA7-PD法のeBA-FVと有意差はなく, LB-PD法は有意に高値だった. 誤差率はA7-FP法で39±42%, A7-PD法で47±45%で両者間に有意差はなく, LB-PDは83±59%で他2者より有意に大きく (p=0.025), pBA-FV, cPA-FV補正による有意の変化はなかった. 超音波による血流量測定値は, 誤差率を勘案すれば臨床的に有用と思われる.

Equipotent subanesthetic concentrations of sevoflurane and xenon preventing cold-stimulated vocalization of neonatal rats.

The effects of inhaled anesthetics on the developing brain are studied using neonatal rodents exposed to fractions of minimum alveolar concentration (to avoid cardiorespiratory compromise). However, these fractions cannot be assumed to be equipotent. Xenon's anesthetic and neuroprotective properties warrant investigation in these models. Therefore, equipotent, subanesthetic concentrations of inhaled anesthetics are needed. Forty-eight Wistar rats (Charles River Laboratories, Kent, United Kingdom) on postnatal day 9 were randomized to eight concentrations of inhaled anesthetics: isoflurane, sevoflurane, or xenon. Exposure was closely monitored in individual metal-based chambers resting on a 35°C mat to maintain normothermia. A 25°C mat was used to stimulate vocalization and a sound recording made (1 min, 1 to 100 kHz). Rectal temperature or partial pressure of carbon dioxide and pH of mixed arteriovenous blood were measured immediately after the exposure. Concentration-response models were constructed using logistic regression (dependent variable: vocalization and explanatory variable: concentration). The effects of all other explanatory variables were assessed by inserting them individually into the model. The effective inhaled concentrations preventing cold-stimulated vocalization in 50 and 95% of neonatal rats (EiC50 and EiC95) on postnatal day 9 were 0.46 and 0.89% sevoflurane and 20.15 and 34.81% xenon, respectively. The effect on the EiC50 of all other explanatory variables, including duration, was minimal. Stability of EiC50 isoflurane was not achieved over three durations (40, 80, and 120 min exposure). Partial pressure of carbon dioxide and pH in mixed arteriovenous blood appeared normal. The authors report equipotent subanesthetic concentrations of sevoflurane and xenon in neonatal rats with preserved cardiopulmonary function. This may be useful in designing neonatal rodent models of anesthesia.

人造血管在血液透析造瘘的应用及护理

Objective: To study the application of artificial blood vessels to build alternative standard arteriovenous fistula blood vessels for hemodialysis maintenance nursing. Methods: 17 cases of patients underwent artificial blood vessel transplantation, material for ptfe (PTEE), 30 cm in length, inner diameter 5mm, from 2012 to 2013 in Jinan military region general hospital. Artificial blood vessel transplantation is more operated on brachial vein, cephalic vein, median cubital vein and basilic vein. When the anastomosis among artificial blood vessels and brachial artery and vein anastomosis was established, the arterial end was on the inner side. When the anastomosis among brachial vein, median cubital vein and basilic vein was established, the arterial end was on the outside for the extension of vascular access. Results: 15 cases have hemodialysis after two months’ treatment, 1 case have artificial blood vessel fistula after swelling for 4 months, infection of thrombosis occurred one month after the operation in 1 case. Conclusion: Artificial blood vessel show good biocompatibility, high long-term patency rate, blood flow, and convenient puncture point. It builds the “lifeline” for the patients who are unable to establish a good vascular access. It is of great significance to improve the management of artificial blood vessel fistula for maintenance hemodialysis patients.

Beta2-adrenoceptor stimulation has no effect on skeletal muscle glucose uptake.

Blockade of the β-adrenergic receptor induces insulin resistance and chronic β-adrenoceptor stimulation improves insulin sensitivity in animals. We tested whether acute β2-adrenoceptor stimulation increased insulin-induced glucose uptake in human forearm skeletal muscle. During a hyperinsulinemic euglycemic clamp procedure, forearm glucose uptake was calculated by multiplying the arteriovenous glucose gradient and forearm blood flow before and during local infusion of the β2-adrenoceptor salbutamol into the brachial artery. β2-Adrenergic stimulation had no effect on insulin-stimulated glucose uptake in human forearm skeletal muscle.

Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle

Increasing amino acid availability (via infusion or ingestion) at rest or postexercise enhances amino acid transport into human skeletal muscle. It is unknown whether alterations in amino acid availability, from ingesting different dietary proteins, can enhance amino acid transport rates and amino acid transporter (AAT) mRNA expression. We hypothesized that the prolonged hyperaminoacidemia from ingesting a blend of proteins with different digestion rates postexercise would enhance amino acid transport into muscle and AAT expression compared with the ingestion of a rapidly digested protein. In a double-blind, randomized clinical trial, we studied 16 young adults at rest and after acute resistance exercise coupled with postexercise (1 h) ingestion of either a (soy-dairy) protein blend or whey protein. Phenylalanine net balance and transport rate into skeletal muscle were measured using stable isotopic methods in combination with femoral arteriovenous blood sampling and muscle biopsies obtained at rest and 3 and 5 h postexercise. Phenylalanine transport into muscle and mRNA expression of select AATs [system L amino acid transporter 1/solute-linked carrier (SLC) 7A5, CD98/SLC3A2, system A amino acid transporter 2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, cationic amino acid transporter 1/SLC7A1] increased to a similar extent in both groups (P < 0.05). However, the ingestion of the protein blend resulted in a prolonged and positive net phenylalanine balance during postexercise recovery compared with whey protein (P < 0.05). Postexercise myofibrillar protein synthesis increased similarly between groups. We conclude that, while both protein sources enhanced postexercise AAT expression, transport into muscle, and myofibrillar protein synthesis, postexercise ingestion of a protein blend results in a slightly prolonged net amino acid balance across the leg compared with whey protein.

Nursing of neonatal hyperbilirubinemia patients suffering from peripheral arteriovenous blood transfusion surgery

Objective To explore the effect and nursing point of peripheral arteriovenous blood transfusion surgery in neonatal hyperbilirubinemia patients .Methods One hundred and twelve neonatal hyperbilirubinemia patients from January 2006 to January 2013 were chosen and divided into the control group and the observation group , each with 56 cases.The two groups respectively received the radial artery and brachial blood transfusion surgery .The preparation , coordination and nursing work were strengthened before , during and after operation .The changes of bilirubin , blood routine , electrolyte , blood glucose and the rate of adverse reaction were compared between the two groups .Results The plugging , low posture , unstable blood pressure, leakage, bleeding and the disorder of respiratory and circulatory were not found in all patients .The levels of total and indirect bilirubin were respectively （473.81 ±135.97）, （373.34 ±115.87）μmol/L before the blood transfusion surgery, which were higher than （223.09 ±87.16）, （192.98 ±76.89）μmol/L after surgery, and the differences were statistically significant （t =2.812, 2.968, respectively; P 0.05）. Conclusions The sufficient preparation before operation , gentle movements and good operational details during operation, monitoring and careful nursing during and after operation are the effective means of ensuring the success of peripheral arteriovenous blood transfusion surgery . Key words: Hyperbilirubinemia,neonatal; Nursing; Peripheral arteriovenous blood transfusion surgery; Monitoring