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1.
Rev. flum. odontol ; 3(59): 1-7, set.-dez. 2022. ilus
Artigo em Português | LILACS, BBO - Odontologia | ID: biblio-1380373

RESUMO

A Fibrina Rica em Plaquetas (PRF) é caracterizada por sua abrangente aplicabilidade na Odontologia. Neste sentido, a venopunção é uma etapa fundamental para sua obtenção. Tal procedimento consiste na identificação das veias superficiais, localizadas na região da fossa antecubital dos membros superiores, para que através da utilização do sistema a vácuo de coleta seja obtido o sangue venoso do paciente. O objetivo deste trabalho é realizar um guia prático abordando cada etapa que compreende a coleta sanguínea para produção do PRF permitindo sua reprodutibilidade de forma segura e eficiente.


Platelet Rich Fibrin (PRF) is characterized by its wide applicability in Dentistry. In this sense, venipuncture is a fundamental step towards obtaining it. Such procedure consists of the identification of superficial veins, located in the region of the antecubital fossa of the upper limbs, so that through the use of the vacuum collection system, the patient's venous blood is obtained. The objective of this work is to carry out a practical guide covering each step that comprises the blood collection for the production of the PRF allowing its reproducibility in a safe and efficient way.


Assuntos
Veias , Coleta de Amostras Sanguíneas , Odontologia , Fibrina Rica em Plaquetas
2.
Sci Rep ; 12(1): 15277, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-36088359

RESUMO

Refilling of the vascular space through absorption of interstitial fluid by micro vessels is a crucial mechanism for maintaining hemodynamic stability during hemodialysis (HD) and allowing excess fluid to be removed from body tissues. The rate of vascular refilling depends on the imbalance between the Starling forces acting across the capillary walls as well as on their hydraulic conductivity and total surface area. Various approaches have been proposed to assess the vascular refilling process during HD, including the so-called refilling coefficient (Kr) that describes the rate of vascular refilling per changes in plasma oncotic pressure, assuming that other Starling forces and the flow of lymph remain constant during HD. Several studies have shown that Kr decreases exponentially during HD, which was attributed to a dialysis-induced decrease in the whole-body capillary hydraulic conductivity (LpS). Here, we employ a lumped-parameter mathematical model of the cardiovascular system and water and solute transport between the main body fluid compartments to assess the impact of all Starling forces and the flow of lymph on vascular refilling during HD in order to explain the reasons behind the observed intradialytic decrease in Kr. We simulated several HD sessions in a virtual patient with different blood priming procedures, ultrafiltration rates, session durations, and constant or variable levels of LpS. We show that the intradialytic decrease in Kr is not associated with a possible reduction of LpS but results from the inherent assumption that plasma oncotic pressure is the only variable Starling force during HD, whereas in fact other Starling forces, in particular the oncotic pressure of the interstitial fluid, have an important impact on the transcapillary fluid exchange during HD. We conclude that Kr is not a good marker of LpS and should not be used to guide fluid removal during HD or to assess the fluid status of dialysis patients.


Assuntos
Capilares , Diálise Renal , Simulação por Computador , Humanos , Ultrafiltração , Veias
3.
J Infus Nurs ; 45(5): 252-257, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36112872

RESUMO

No information exists on the minimum number of times that fist clenching should be performed to increase vein visibility and palpability. In this study, the researchers aimed to determine the average number and duration of fist clenching to increase vein visibility and palpability before peripheral intravenous catheter insertion. This observational study included 207 healthy individuals. Participants meeting the inclusion criteria were asked to perform fist clenching. The number and duration of fist clenches performed to increase dorsal metacarpal vein and cephalic vein grade were determined. The participants carried out fist clenching 7.57 ± 4.26 times for the first increase and 22.16 ± 7.93 times for the second increase in dorsal metacarpal vein grade. Fist clenching was carried out 10.05 ± 7.30 times for the first increase and 21.30 ± 7.86 times for the second increase in cephalic vein visibility. A statistically significant, weak, but positive relationship was observed between the duration of fist clenching and the change in dorsal metacarpal vein grade and anxiety level ( r = 0.194, P < .005). However, the relationship was negative between room temperature and the duration of fist clenching in dorsal metacarpal vein grade ( r = -0.207, P = .003). This inexpensive and simple technique should be performed in specified numbers before catheter insertion.


Assuntos
Cateterismo Periférico , Veias , Mãos , Humanos
4.
Sensors (Basel) ; 22(16)2022 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-36015799

RESUMO

In today's information age, how to accurately identify a person's identity and protect information security has become a hot topic of people from all walks of life. At present, a more convenient and secure solution to identity identification is undoubtedly biometric identification, but a single biometric identification cannot support increasingly complex and diversified authentication scenarios. Using multimodal biometric technology can improve the accuracy and safety of identification. This paper proposes a biometric method based on finger vein and face bimodal feature layer fusion, which uses a convolutional neural network (CNN), and the fusion occurs in the feature layer. The self-attention mechanism is used to obtain the weights of the two biometrics, and combined with the RESNET residual structure, the self-attention weight feature is cascaded with the bimodal fusion feature channel Concat. To prove the high efficiency of bimodal feature layer fusion, AlexNet and VGG-19 network models were selected in the experimental part for extracting finger vein and face image features as inputs to the feature fusion module. The extensive experiments show that the recognition accuracy of both models exceeds 98.4%, demonstrating the high efficiency of the bimodal feature fusion.


Assuntos
Identificação Biométrica , Algoritmos , Identificação Biométrica/métodos , Biometria , Humanos , Redes Neurais de Computação , Veias
5.
Zh Vopr Neirokhir Im N N Burdenko ; 86(4): 104-108, 2022.
Artigo em Russo | MEDLINE | ID: mdl-35942844

RESUMO

BACKGROUND: Intracranial hemorrhage is the most common complication of cerebral arteriovenous malformations (AVM). In recent years, most studies devoted to the features of AVM functioning consider venous drainage as important factor influencing the rupture of malformation. OBJECTIVE: To review the literature data on the relationship between the features of venous drainage of cerebral arteriovenous malformations and intracranial hemorrhage. MATERIAL AND METHODS: We found 43 studies discussing the features of AVM venous drainage for the period from 1982 to 2020. Most of reports were published between 2005 and 2020. RESULTS: Deep venous drainage and a single drainage vein were the most significant factors influencing the risk of hemorrhage. Venous ectasia, reflux, stenosis, number, length and tortuosity of drainage veins were less important for the risk of AVM rupture. CONCLUSION: Analysis of the features of AVM venous drainage can make it possible to predict the natural course of disease and risk of intracranial hemorrhage. These aspects are essential for neurosurgical treatment.


Assuntos
Hemorragia Cerebral , Malformações Arteriovenosas Intracranianas , Drenagem/efeitos adversos , Humanos , Malformações Arteriovenosas Intracranianas/complicações , Malformações Arteriovenosas Intracranianas/diagnóstico por imagem , Malformações Arteriovenosas Intracranianas/cirurgia , Hemorragias Intracranianas/etiologia , Estudos Retrospectivos , Veias
6.
Cell Mol Life Sci ; 79(9): 491, 2022 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-35987946

RESUMO

Endothelial cells in veins differ in morphology, function and gene expression from those in arteries and lymphatics. Understanding how venous and arterial identities are induced during development is required to understand how arterio-venous malformations occur, and to improve the outcome of vein grafts in surgery by promoting arterialization of veins. To identify factors that promote venous endothelial cell fate in vivo, we isolated veins from quail embryos, at different developmental stages, that were grafted into the coelom of chick embryos. Endothelial cells migrated out from the grafted vein and their colonization of host veins and/or arteries was quantified. We show that venous fate is promoted by sympathetic vessel innervation at embryonic day 11. Removal of sympathetic innervation decreased vein colonization, while norepinephrine enhanced venous colonization. BMP treatment or inhibition of ERK enhanced venous fate, revealing environmental neurotransmitter and BMP signaling and intrinsic ERK inhibition as actors in venous fate acquisition. We also identify the BMP antagonist Noggin as a potent mediator of venous arterialization.


Assuntos
Células Endoteliais , Veias , Animais , Artérias , Diferenciação Celular/fisiologia , Embrião de Galinha , Transdução de Sinais , Veias/metabolismo
7.
Medicina (Kaunas) ; 58(8)2022 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-36013532

RESUMO

Background and Objectives: Retrograde free venous flaps represent a separate entity among free venous flaps: their physiology is still unclear, but they provide an immediate visible refill after reconnection, with a similar behaviour to conventional flaps. Therefore, the dimensions and the indications of these flaps can be extended beyond what was previously believed, and they can be easily customized, including with respect to tendons and nerves. Nevertheless, they are still debated and regarded as unsafe. Materials and Methods: From 2012 to 2019, we performed 31 retrograde free venous flaps on 31 patients to reconstruct hands, digits, and in one case the heel. All the flaps were arterialized in a retrograde manner; the donor site was the forearm in 28 cases, the foot in 2 cases, and the calf in 1 case. We recorded the size, vein architecture, donor site, donor artery, donor morbidity, function for composite and non-composite flaps, immediate complications, late complications, survival rate, and the number of revisions. We recorded the hand function when appropriate. A total of 10 flaps were also intraoperatively studied with indocyanine green to monitor their hemodynamical behaviour. Results: All the patients were followed for an average of 8 months (6-15). The flap dimensions ranged from 6 cm2 to 136 cm2. All the flaps, except two that had complete necrosis, survived. Two flaps had partial necrosis. There was no correlation between necrosis and the size of the flap, with one case of necrosis and one of partial necrosis in the small flaps (<10 cm2). None of the cases with partial necrosis needed a new flap. Two flaps developed a late arterio-venous shunt that was ligated. Conclusions: The retrograde free venous flaps proved to be a useful tool for complex reconstructions of the hand and extremities. They can provide a large island of pliable skin and composite tissue with tendons and nerves, but surgeons must be aware of some caveats.


Assuntos
Traumatismos da Mão , Lesões dos Tecidos Moles , Antebraço/cirurgia , Traumatismos da Mão/cirurgia , Humanos , Necrose , Lesões dos Tecidos Moles/cirurgia , Retalhos Cirúrgicos/irrigação sanguínea , Veias/cirurgia
8.
PLoS One ; 17(8): e0272566, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35939451

RESUMO

BACKGROUND: Although compression therapy is well established for patients with deep venous thrombosis (DVT) and chronic venous disease (CVD), considerable variation exists in its organization in clinical practice which may impact patient outcomes. The current study aims to deepen our understanding of the main drivers of the complex care organization for compression therapy and to identify targets for improvement. METHODS: This realist evaluation includes a mixed-method design consisting of semi-structured interviews with patients and health care professionals involved in compression therapy (n = 30), stakeholder meetings (n = 2) and surveys (n = 114). Data were collected to create the content of context-mechanism-outcome-configurations (CMOcs) important in compression therapy. Based on these CMOcs, targets for improvement to optimize the organization of compression care were identified. RESULTS: We identified overarching context factors and mechanisms targeting four optimal outcomes for the organization of compression therapy: selecting initial compression therapy types that support patient's self-reliance (1), evidence based selection of elastic compression stocking type and class (2), patient-based selection of assistive devices (3), individualizing treatment duration for DVT patients (4a) and providing follow-up for CVD patients (4b). We found that increasing health care professionals' knowledge of compression therapy, the availability of unambiguous protocols and guidelines, increasing patient involvement (and if applicable their informal care giver) in the decision making process, the accessible availability of resources, and increasing interdisciplinary consultation enhanced desirable outcomes. These targets triggered mechanisms such as increased health care professionals' willingness, confidence and motivation to provide patient-based care and increased patients' self-confidence and self-efficacy. CONCLUSIONS: This study provides a detailed insight into what needs to be in place to optimize compression care and identified five main targets for improvement.


Assuntos
Síndrome Pós-Trombótica , Doenças Vasculares , Doença Crônica , Humanos , Síndrome Pós-Trombótica/etiologia , Meias de Compressão/efeitos adversos , Inquéritos e Questionários , Doenças Vasculares/etiologia , Veias
9.
Respir Care ; 67(9): 1190-1204, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36002161

RESUMO

In the absence of an indwelling arterial catheter, capillary blood gas sampling may be used to evaluate the acid/base and ventilation status of neonatal and pediatric patients with cardiorespiratory conditions. These guidelines were developed from a comprehensive review of the literature to provide guidance for the collection, handling, and interpretation of blood obtained from an arterialized capillary sample. Capillary and venous blood gas measurements are a useful alternative to arterial blood gas measurements for neonatal and pediatric patients who do not require close monitoring of [Formula: see text] In the presence of alterations in body temperature, blood pressure, or peripheral perfusion, agreement between a capillary blood gas with an arterial sample is recommended to determine whether changes in these physiologic conditions reduce reliability. Perfusion to the sample site should be assessed and preference given to blood sampling from a well perfused site, and blood should be analyzed within 15 min of sampling to minimize the propensity for pre-analytical errors. Clinicians should consider re-collecting a blood sample, obtained from an artery, vein, or capillary, when the blood gas or analyte result interpretation does not align with the patient's clinical presentation. A pneumatic tube system can be reliably used to transport blood gas samples collected in a syringe and capillary tube to a clinical laboratory for analysis. To reduce the cumulative pain effect and risk of complications, the capillary puncture procedure should be minimized when possible. Non-pharmacologic interventions should be used to reduce pain associated with capillary blood gas sampling. Automatic lancets are preferred to puncture the skin for capillary blood gas collection.


Assuntos
Coleta de Amostras Sanguíneas , Veias , Gasometria/métodos , Coleta de Amostras Sanguíneas/métodos , Capilares , Criança , Humanos , Recém-Nascido , Dor , Reprodutibilidade dos Testes
10.
Biosensors (Basel) ; 12(8)2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-36005008

RESUMO

The study of brain venous drainage has gained attention due to its hypothesized link with various neurological conditions. Intracranial and neck venous flow rate may be estimated using cardiac-gated cine phase-contrast (PC)-MRI. Although previous studies showed that breathing influences the neck's venous flow, this aspect could not be studied using the conventional segmented PC-MRI since it reconstructs a single cardiac cycle. The advent of real-time PC-MRI has overcome these limitations. Using this technique, we measured the internal jugular veins and superior sagittal sinus flow rates in a group of 16 healthy subjects (12 females, median age of 23 years). Comparing forced-breathing and free-breathing, the average flow rate decreased and the respiratory modulation increased. The flow rate decrement may be due to a vasoreactive response to deep breathing. The respiratory modulation increment is due to the thoracic pump's greater effect during forced breathing compared to free breathing. These results showed that the breathing mode influences the average blood flow and its pulsations. Since effective drainage is fundamental for brain health, rehabilitative studies might use the current setup to investigate if respiratory exercises positively affect clinical variables and venous drainage.


Assuntos
Coração , Imageamento por Ressonância Magnética , Adulto , Encéfalo , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Respiração , Veias , Adulto Jovem
12.
Ulus Travma Acil Cerrahi Derg ; 28(9): 1312-1316, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36043933

RESUMO

BACKGROUND: Ultrasound-guided vein cannulation is an essential skill in emergency medicine. Prohibitive costs of commercial ultrasound phantoms limit the ability to adequately train residents. We assess the clinical utility of homemade phantoms for medical education. METHODS: Eighteen emergency medicine residents each performed 10 ultrasound-guided IV attempts on patients, half of the attempts before and half after a training course using two homemade ultrasound phantoms with 14 total Penrose drains. We conducted a prospective feasibility study using pre- and post-training surveys comparing confidence and success rates of IV cannulation attempts on patients. RESULTS: Residents demonstrated an improvement in successful ultrasound-guided peripheral vein cannulations from an average of 47.8% during the first five attempts to 71.1% in the last five attempts. No benefit was noted from the first to the fifth attempts, nor from the six to the tenth attempts, suggesting minimal benefit from experience early on. Residents reported increased confidence in performing ultrasound-guided venous cannulation on patients, identifying the correct probe, adjusting gain and depth, visualizing veins in short and long axis, differentiating arteries from veins, and vein cannulation on a phantom model. CONCLUSION: Homemade ultrasound phantoms are cost effective, increase confidence, and improve emergency medicine residents' ability to perform ultrasound-guided vein cannulation.


Assuntos
Cateterismo Venoso Central , Medicina de Emergência , Cateterismo , Medicina de Emergência/educação , Humanos , Veias Jugulares , Estudos Prospectivos , Ultrassonografia de Intervenção , Veias/diagnóstico por imagem
13.
J Infus Nurs ; 45(4): 220-224, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35820127

RESUMO

In the past 30 years, midline catheter use has grown rapidly. For several reasons, many providers and facilities are attempting to reduce the number of central venous catheters and subsequent central line-associated bloodstream infections (CLABSIs) by using midline catheters. Vessel preservation requires attention to all vascular access device (VAD)-associated complications and not only central line bloodstream infection. There is still much confusion about the appropriate tip location and the characteristics of fluids and medications that can safely be infused through a midline catheter residing in a peripheral vein. The Infusion Therapy Standards of Practice (the Standards) focuses on assessment of characteristics of infusion therapies that must be considered for VAD selection as an evidence-based list of fluids and medications for infusion through peripheral veins has yet to be established. This review of midline catheter studies evaluates the evidence regarding the substitution of a midline catheter for a central venous catheter. Many issues need to be addressed, such as studies that include an outcome list that mixes defined clinical complications (eg, thrombosis) with signs and symptoms of complications (eg, leaking). Another issue is basing a major change of clinical practice on retrospective chart reviews. Although a midline catheter may be appropriate for some patients, additional studies of a higher level of evidence are needed before this major practice change should occur.


Assuntos
Cateterismo Periférico , Cateteres Venosos Centrais , Trombose , Cateteres Venosos Centrais/efeitos adversos , Humanos , Estudos Retrospectivos , Veias
14.
Med Eng Phys ; 105: 103814, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35781379

RESUMO

Despite arteriovenous fistulae (AVF) being the preferred vascular access for haemodialysis, high primary failure rates (30-70%) and low one-year patency rates (40-70%) hamper their use. Furthermore, AVF creation has been associated with haemodynamic changes causing maladaptive cardiac remodelling leading to cardiovascular (CV) complications. In this study, we present a new workflow for characterising the haemodynamic profile prior to and following surgical creation of a successful left radiocephalic AVF in a 20-year-old end-stage kidney disease patient. The reconstructed vasculature was generated using multiple ferumoxytol-enhanced magnetic resonance angiography (FeMRA) datasets. Computational fluid dynamics (CFD) simulations utilising a scale-resolving turbulence model were completed to investigate the changes in the proximal haemodynamics following AVF creation, in addition to the post-AVF juxta-anastomosis flow patterns, which is impractical to obtain in-vivo. Following AVF creation, a significant 2-3-fold increase in blood flow rate was induced downstream of the left subclavian artery. This was validated through comparison with post-AVF patient-specific phase-contrast data. Proximal to the anastomosis, the increased flow rate yielded an increase in time-averaged wall shear stress (WSS), which is a key marker of adaptive vascular remodelling. In the juxta-anastomosis region, the success of the AVF was discussed with respect to the National Kidney Foundation's vascular access guidelines, where the patient-specific AVF met the flow rate and geometry criterion. The AVF venous diameter exceeded 6mm and the venous flow rate surpassed 600mL/min. This workflow may potentially be significant clinically when applied to multi-patient cohorts, with population-wide patient-specific conclusions being ascertained for the haemodynamic assessment of AVFs and improved surgical planning.


Assuntos
Fístula Arteriovenosa , Adulto , Fístula Arteriovenosa/cirurgia , Humanos , Rim , Diálise Renal , Artéria Subclávia , Veias , Adulto Jovem
15.
PLoS One ; 17(7): e0269825, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35862379

RESUMO

OBJECTIVE: The hemodynamic benefit of novel arteriovenous graft (AVG) designs is typically assessed using computational models that assume highly idealized graft configurations and/or simplified boundary conditions representing the peripheral vasculature. The objective of this study is to evaluate whether idealized AVG models are suitable for hemodynamic evaluation of new graft designs, or whether more realistic models are required. METHODS: An idealized and a realistic, clinical imaging based, parametrized AVG geometry were created. Furthermore, two physiological boundary condition models were developed to represent the peripheral vasculature. We assessed how graft geometry (idealized or realistic) and applied boundary condition models of the peripheral vasculature (physiological or distal zero-flow) impacted hemodynamic metrics related to AVG dysfunction. RESULTS: Anastomotic regions exposed to high WSS (>7, ≤40 Pa), very high WSS (>40 Pa) and highly oscillatory WSS were larger in the simulations using the realistic AVG geometry. The magnitude of velocity perturbations in the venous segment was up to 1.7 times larger in the realistic AVG geometry compared to the idealized one. When applying a (non-physiological zero-flow) boundary condition that neglected blood flow to and from the peripheral vasculature, we observed large regions exposed to highly oscillatory WSS. These regions could not be observed when using either of the newly developed distal boundary condition models. CONCLUSION: Hemodynamic metrics related to AVG dysfunction are highly dependent on the geometry and the distal boundary condition model used. Consequently, the hemodynamic benefit of a novel graft design can be misrepresented when using idealized AVG modelling setups.


Assuntos
Modelos Cardiovasculares , Diálise Renal , Simulação por Computador , Hemodinâmica/fisiologia , Diálise Renal/métodos , Veias
17.
Clin Imaging ; 89: 136-146, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35809476

RESUMO

The Superior Ophthalmic Vein (SOV) is the largest vein of the orbit and represents an important orbital venous drainage pathway. SOV is well identifiable on CT and MRI, and its alterations may be a clue for differential diagnosis. In this pictorial work we illustrate the most frequent conditions in which SOV appearance may be influenced by various pathologies, providing a pictorial guide for imaging interpretation.


Assuntos
Seio Cavernoso , Humanos , Imageamento por Ressonância Magnética , Órbita/irrigação sanguínea , Órbita/diagnóstico por imagem , Veias/diagnóstico por imagem
18.
J Plast Reconstr Aesthet Surg ; 75(8): 2831-2870, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35821010

RESUMO

Immediate lymphatic reconstruction (ILR) is targeted at preventing breast cancer related lymphedema (BCRL) by anastomosing disrupted arm lymphatic channels to axillary vein tributaries. Inadequate vein length and venous back-bleeding are two technical reasons that lead to ILR procedures being aborted intraoperatively. Recently, our team began routinely harvesting a lower extremity vein graft (LEVG) for all ILR procedures to reduce our abort rate. We describe the surgical approach of an LEVG and evaluate the effects on aborted case rates and intraoperative time. A retrospective review of our institutional lymphatic database was conducted. Two hundred and forty-seven breast cancer patients were taken to the operating room for attempted ILR in the past 5 years. Prior to the use of an LEVG (n = 205), our abort rate was 14%. Since routinely performing an LEVG with ILR (n = 42), we have not aborted a single case. Despite an LEVG requiring one additional anastomosis to connect the vein graft to the native axillary vein tributary, this technique has not changed the intraoperative time for ILR procedures. In this technical contribution, we describe our early experience performing immediate lymphatic reconstruction utilizing a lower extremity vein graft. Implementation of this technique appears to have promising effects on aborted case rates without affecting intraoperative time, and greatly facilitates the lymphovenous anastomosis.


Assuntos
Linfedema Relacionado a Câncer de Mama , Vasos Linfáticos , Linfedema , Anastomose Cirúrgica , Humanos , Extremidade Inferior/cirurgia , Vasos Linfáticos/cirurgia , Linfedema/etiologia , Linfedema/prevenção & controle , Linfedema/cirurgia , Veias/cirurgia
19.
Radiographics ; 42(5): 1532-1545, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35867595

RESUMO

The pelvic venous system is complex, with the potential for numerous pathways of collateralization. Owing to stenosis or occlusion, both thrombotic and nonthrombotic entities in the pelvis may necessitate alternate routes of venous return. Although the pelvic venous anatomy and collateral pathways may demonstrate structural variability, a number of predictable paths often can be demonstrated on the basis of the given disease and the level of obstruction. Several general categories of collateral pathways have been described. These pathway categories include the deep pathway, which is composed of the lumbar and sacral veins and vertebral venous plexuses; the superficial pathway, which is composed of the circumflex and epigastric vessels; various iliofemoral collateral pathways; the intermediate pathway, which is composed of the gonadal veins and the ovarian and uterine plexuses; and portosystemic pathways. The pelvic venous anatomy has been described in detail in cadaveric and anatomic studies, with the aforementioned collateral pathways depicted on CT and MR images in several imaging studies. A comprehensive review of the native pelvic venous anatomy and collateralized pelvic venous anatomy based on angiographic features has yet to be provided. Knowledge of the diseases involving a number of specific pelvic veins is of clinical importance to interventional and diagnostic radiologists and surgeons. The ability to accurately identify common collateral patterns by using multiple imaging modalities, with accurate anatomic descriptions, may assist in delineating underlying obstructive hemodynamics and diagnosing specific occlusive disease entities. ©RSNA, 2022.


Assuntos
Doenças Vasculares , Veias , Abdome , Circulação Colateral , Humanos , Pelve/irrigação sanguínea , Pelve/diagnóstico por imagem , Flebografia/métodos
20.
Adv Physiol Educ ; 46(3): 461-467, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35759527

RESUMO

Pulse oximetry has become the standard of care in operating rooms, intensive care units, and hospitals worldwide. A pulse oximeter continuously and noninvasively monitors the functional oxygen saturation of hemoglobin in arterial blood ([Formula: see text]). [Formula: see text] is so important in medical care that it is often regarded as a fifth vital sign. Before pulse oximetry, arterial puncture for blood gas analysis was the only method available to determine [Formula: see text] and to identify the presence of hypoxemia. Pulse oximetry is based on the principle that oxygenated hemoglobin (O2Hb) absorbs more near-infrared light than deoxyhemoglobin (HHb) and HHb absorbs more red light than O2Hb. It is important to understand the principles of pulse oximetry, how the equipment works, and its limitations to interpret the information it provides. Accordingly, we used colored balloons to introduce the physics of how a pulse oximeter detects and measures oxyhemoglobin and deoxyhemoglobin in pulsatile (arterial) and nonpulsatile (venous and capillary) blood. The foundations of oximetry started in the 1700s with Johann Lambert (1728-1777). We approached this complex physics in a straightforward way while still providing an understanding of the fundamental concepts developed by Johann Lambert in 1760.NEW & NOTEWORTHY Educators must go beyond teaching the facts and encourage students to think, investigate, and appreciate the subject matter in a broader framework. To achieve these goals, we used a simple and inexpensive experimental approach to introduce the physics of how a pulse oximeter detects and measures oxyhemoglobin and deoxyhemoglobin in blood. We approached this complex physics in a straightforward way while still providing an understanding of the fundamental concepts developed by Johann Lambert in 1760.


Assuntos
Oximetria , Oxiemoglobinas , Hemoglobinas , Humanos , Oximetria/métodos , Oxigênio , Veias
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