High Blood Flow Rates Research Articles

Reliable Stenosis Detection Based on Thrill Waveform Analysis Using Non-Contact Arteriovenous Fistula Imaging.

Hemodialysis therapy is an extracorporeal circulation treatment that serves as a substitute for renal function. In Japan, patients receive this efficient four-hour treatment, three times per week, allowing them to maintain a social life nearly equivalent to that of healthy individuals. Before the treatment, two punctures are performed to establish extracorporeal circulation, and a high blood flow rate is essential to ensure efficient therapy. Specialized blood vessels created through arteriovenous fistula (AVF) surgery are utilized to achieve high blood flow rates. Although the AVF allows safe and efficient dialysis treatment, AVF stenosis leads to a serious problem in dialysis. To early detect this abnormal blood flow, auscultation and palpation methods are widely used in hospitals. However, these methods can only provide qualitative judgment of the AVF condition, so the results cannot be shared among other doctors and staff. Additionally, since the conventional methods require contact with the skin, some issues require consideration regarding infection and low reproducibility. In our previous study, we proposed an alternative method for auscultation using non-contact optical imaging technology. This study aims to construct a reliable AVF stenosis detection method using Thrill waveform analysis based on the developed non-contact device to solve the problem with the contact palpation method. This paper demonstrates the performance validation of the non-contact imaging in the normal AVF group (206 total data, 75 patients, mean age: 69.1 years) and in the treatable stenosis group (107 total data, 17 patients, mean age: 70.1 years). The experimental results of the Mann-Whitney U test showed a significant difference (p=0.0002) between the normal and abnormal groups, which indicated the effectiveness of the proposed method as a new possible alternative to palpation.

Clinical diagnostic value of contrast-enhanced ultrasound combined with microflow imaging in benign and malignant renal tumors: A retrospective cohort study.

This study aims to evaluate the clinical diagnostic value of contrast-enhanced ultrasound combined with microflow imaging (CEUS-MFI) in the differential diagnosis of benign and malignant renal tumors. All patients underwent CEUS, MFI, color doppler flow imaging (CDFI), and CEUS-MFI. The efficacies of these different diagnostic modalities in diagnosing benign and malignant renal tumors were evaluated by Kappa consistency test and the receiver operating characteristic (ROC) curve, with pathological findings serving as the gold standard. CDFI, MFI and CEUS-MFI all demonstrated higher blood flow in malignant tumors compared with benign tumors. Compared with benign tumors, CDFI detected a higher rate of punctate and linear Adler grade 2 and 3 blood flows in malignant tumors, as well as peripheral semicircular or annular blood flow. MFI identified a high rate of peripheral circumferential blood flow and irregular vascular morphology in malignant tumors, with most exhibiting Adler grade 3 blood flow. In addition, CEUS-MFI showed more dendritic or irregular Adler grade 2 or 3 blood flows in malignant renal tumors than MFI alone. Further analysis showed that CEUS-MFI had the highest consistency with pathological diagnosis (Kappa = 0.808). The ROC curve showed that the area under the curve (AUC) for CEUS-MFI in differentiating between benign and malignant lesions was 0.898, significantly outperforming other single diagnostic methods. With its capability to display microvascular information and assess overall pathological characteristics, MFI can accurately predict the nature of renal tumors and assist in surgical planning.

Clinical diagnostic value of contrast-enhanced ultrasound combined with microflow imaging in benign and malignant renal tumors: A retrospective cohort study.

This study aims to evaluate the clinical diagnostic value of contrast-enhanced ultrasound combined with microflow imaging (CEUS-MFI) in the differential diagnosis of benign and malignant renal tumors. All patients underwent CEUS, MFI, color doppler flow imaging (CDFI), and CEUS-MFI. The efficacies of these different diagnostic modalities in diagnosing benign and malignant renal tumors were evaluated by Kappa consistency test and the receiver operating characteristic (ROC) curve, with pathological findings serving as the gold standard. CDFI, MFI and CEUS-MFI all demonstrated higher blood flow in malignant tumors compared with benign tumors. Compared with benign tumors, CDFI detected a higher rate of punctate and linear Adler grade 2 and 3 blood flows in malignant tumors, as well as peripheral semicircular or annular blood flow. MFI identified a high rate of peripheral circumferential blood flow and irregular vascular morphology in malignant tumors, with most exhibiting Adler grade 3 blood flow. In addition, CEUS-MFI showed more dendritic or irregular Adler grade 2 or 3 blood flows in malignant renal tumors than MFI alone. Further analysis showed that CEUS-MFI had the highest consistency with pathological diagnosis (Kappa = 0.808). The ROC curve showed that the area under the curve (AUC) for CEUS-MFI in differentiating between benign and malignant lesions was 0.898, significantly outperforming other single diagnostic methods. With its capability to display microvascular information and assess overall pathological characteristics, MFI can accurately predict the nature of renal tumors and assist in surgical planning.

Extracorporeal Blood Treatment Using Functional Magnetic Nanoclusters Mitigates Organ Dysfunction of Sepsis in Swine.

Mitigating sepsis-induced severe organ dysfunction with magnetic nanoparticles has shown remarkable advances in extracorporeal blood treatment. Nevertheless, treating large septic animals remains challenging due to insufficient magnetic separation at rapid blood flow rates (>6 L h-1) and limited incubation time in an extracorporeal circuit. Herein, superparamagnetic nanoclusters (SPNCs) coated with red blood cell (RBC) membranes are developed, which promptly capture and magnetically separate a wide range of pathogens at high blood flow rates in a swine sepsis model. The SPNCs exhibited an ultranarrow size distribution of clustered iron oxide nanocrystals and exceptionally high saturation magnetization (≈ 90 emu g-1) close to that of bulk magnetite. It is also revealed that CD47 on the RBCs allows the RBC-SPNCs to remain at a consistent concentration in the blood by evading innate immunity. The uniform size distribution of the RBC-SPNCs greatly enhances their effectiveness in eradicating various pathogenic materials in extracorporeal blood. The use of RBC-SPNCs for extracorporeal treatment of swine infected with multidrug-resistant E. coli is validated and found that severe bacteremic sepsis-induced organ dysfunction is significantly mitigated after 12 h. The findings highlight the potential application of RBC-SPNCs for extracorporeal therapy of severe sepsis in large animal models and potentially humans.

Vascular access for autologous peripheral blood stem cells collection by large volume leukapheresis: Single center experience.

Peripheral blood stem cell (PBSC) harvesting requires reliable and safe vascular access. In our institution, a change of practice was implemented and the central venous catheter (CVC) placement for all autologous PBSC collections was abandoned in favor of a careful evaluation of peripheral venous access (PVA) for each individual patient. The aim of this prospective study was to evaluate the rate of patients with adequate peripheral veins for autologous PBSC collection and compare patient characteristics, collection efficacy, and complication rate between patients with PVA and CVC. Peripheral veins were assessed by the apheresis nurse team in all patients referred between January 2020 and July 2021 to autologous PBSC collection. Only in case of difficult venous access, CVC was inserted. Large volume leukapheresis (LVL) procedures, which processed ≥3 total blood volumes, were performed. In 65 (57%) patients PVA was used, while 49 (43%) patients required placement of short-term CVC. Peripheral venous access was successfully used significantly more often in males (69.8%) (P = 0.010), and patients with multiple myeloma (71.0%) than in patients with non-Hodgkin's lymphoma (35.9%) and Hodgkin's lymphoma patients (33.3%) (P < 0.001). There was a significant difference in the type of prior administered chemotherapy; in the patients who received cytostatics free chemotherapy, PVA was used more often (75.0%) (P = 0.007). In terms of the efficacy and safety of LVLs, there were no differences between procedures performed using PVA and CVCs. Peripheral venous access is feasible for autologous PBSC collection in more than a half of patients, in particular in those with multiple myeloma. Changes in the treatment of multiple myeloma, using new proteasome inhibitors-based and immunomodulatory agents that do not adversely affect peripheral veins, have enabled the use of PVA even at the high blood flow rates required by LVL. Peripheral venous access is not associated with safety issues or with a lesser collection efficiency, and it is cost-effective as well. Each patient referred to autologous PBSC collection needs to be evaluated individually by the experienced apheresis team for the most appropriate venous access.

#5029 PERCUTANEOUS ARTERIOVENOUS FISTULA CREATION: A DUBAI HOSPITAL EXPERIENCE

Abstract Background and Aims Targeting to improve the quality of care for chronic kidney disease patients (CKD) a non -surgical creation of native arteriovenous fistulae (AVF) with potentially cosmetic advantages, was offered for CKD patients in Dubai. The procedure started in January 2021 and the follow up continued till January 2023. The goal of this report is to share the original first experience in Dubai for this technique using 4F WavelinQ EndoAVF System. Method Fourteen patients underwent sonographic vascular mapping for endovascular AVF creation using 4F WavelinQ EndoAVF System. Nine patients were deemed suitable for Endovascular AVF creation and underwent the procedure under regional anaesthesia. Concomitant ulnar artery and ulnar vein or the concomitant radial artery and radial vein was used for the procedure. Results In this case series, the patients have a mean age of 53 ± 17 years, majority of the cases were men (77.8%). All cases were hypertensives (100%) with 2 cases(22.2%) have biopsy proven Glomerulonephritis and 5 cases (55.5%) were diabetics. The technique succeeded (defined by blood flow from used artery to concomitant deep vein and through perforator vein to superficial vein) in all patients (100%). Maturation success (defined as estimated fistula flow rates exceeded 500 mL/min and access vessel diameter was more than 4 mm) with multiple venous outflows was achieved in 8 cases (88.1%). One case (11.1%) showed primary maturation failure. Five cases (55.5%) achieved successful cannulation with excellent blood flow and reliable arterial and venous pressure during dialysis. Time to maturation was 35 ± 17 days and time to successful cannulation averaged 63 ± 45 days. Among patients achieving maturation success, one patient requested AVF closure (using coil embolization) due to mild to moderate upper limb oedema that required reintervention, one case underwent pre-emptive kidney transplantation and did not require to use the AVF and one patient refused using the AVF. In our study 3 cases (33.3%) required reintervention to facilitate maturation. It worth mention that among the 3 cases underwent reintervention, one case requested closure of the fistula and one case refused to use the fistula and only one case of the successful cannulation group underwent single reintervention. Conclusion In our limited experience, AVF creation using Endovascular technique resulted in dependable haemodialysis access with reliable maturation time, achieving excellent patency in the successful cannulation group with high blood flow rate and accepted arterial and venous pressure during dialysis. It also showed that the procedure was safe with better cosmetic shape and no scars. However more studies with bigger sample size are needed for better evaluation of the technique and to confirm the endovascular AVF creation proper position in the guidelines for vascular access creation in haemodialysis.

PULM4: Silicone-Based Hollow Fiber Membrane Lungs For Long-Term Extracorporeal Respiratory Supports: Initial Results From A Pilot Study Using A Goat Model

Background: There has been an increasing demand of organs for lung transplant to save those who suffer from end-stage lung disease. However, the number of organ donations have never matched that of candidate recipients, leading to a high mortality rate on the waiting period for transplant. One potential approach to decrease the wait-list mortality is to develop an artificial gas-exchange device that can support lung function until the time of transplantation. We’ve started to develop a gas-exchange system that consists of silicone-based membrane lungs with methacryloyloxyethyl phosphorylcholine (MPC) polymer coating and tubing system for a longer-term use. Objective: The purpose of this study was to evaluate the long-term durability, oxygenation, and pressure loss of newly developed artificial lungs using a large animal model. Materials and methods: The surface area of the membrane lung is approximately 2 m2. Central ECMO from the pulmonary artery to the left atrium was introduced to a healthy female goat via left thoracotomy under general anesthesia (N=3). Unfractionated heparin infusion was utilized for anticoagulation (target activating clotting time: 150-200 sec). After recovery from the surgery, blood gas and flow pressure before and after the artificial lung with flow rates of 1, 2, and 3 L/min were tested weekly. Daily physiological data, regular blood biochemistry and coagulation tests, and histopathological findings after autopsy were also evaluated. Thrombus adhesion to the silicone membrane was evaluated using an electron microscopy after the experiments. Results: Durations for testing the artificial lungs were 53, 58, and 100 days. The experiments were terminated due to an accidental tubing event, a sudden cardiac complication, and massive renal hemorrhage. Averages of oxygen transfer rates (ml/min) and oxygen pressure gradients (mmHg) at each flow rate were 63.3 and 466.5 at 1 L/min, 118.3 and 291.3 at 2 L/min, and 152.7 and 138.2 at 3 L/min. Averages of flow pressures through the artificial lungs at each flow rate were 21.7 mmHg at 1 L/min, 44.7 at 2 L/min, and 66.9 at 3 L/min. No significant increase of pressure loss or decrease of oxygenation was observed throughout the experimental periods. Thrombus at the inlet of the membrane was mainly observed, but those inside and near the outlet were minor, indicating the long-term antithrombotic property of the polymer coating. Electron microscopical examinations revealed minimal thrombus formation on the hollow fiber membrane inside the lung. At autopsy, although micro-infarction and thrombus were observed in the heart and kidney, native lungs were well maintained without appreciable congestion. Conclusion: The newly developed MPC polymer-coated silicone-based lungs could be used stably for more than 50 days. Improving the oxygenation in higher blood flow rates with reduced pressure loss is our ongoing subject to work on.

A case report: extracorporeal membrane oxygenation for multitrauma patient with pneumorrhagia

BackgroundExtracorporeal membrane oxygenation (ECMO) can be used as salvage therapy for multitrauma patients with acute respiratory distress syndrome (ARDS) when conventional treatment fails to maintain oxygenation. However, controversy exists between ECMO application and the risk of bleeding due to systemic anticoagulation during the treatment. Non-heparin introduction seems to be a possible solution for this dilemma, owing to technical improvements in the device and management methods of ECMO.Case presentationA 58-year-old woman suffered from blunt thoracic, pelvic, and right lower limb fractures due to a falling accident, which resulted in acute respiratory distress syndrome (ARDS). Although the patient received intubation and mechanical ventilation (MV), respiratory failure was not alleviated. Venous-venous (V-V) ECMO was used as a salvage therapy. With the support of V-V ECMO, we safely cleared blood clots in the bronchus and avoided secondary lung injury caused by pressure trauma and oxygen poisoning of the MV. We introduced heparin-free ECMO management as a solution to reduce the risk of bleeding associated with pulmonary contusion and other organ injuries. To prevent thrombosis, we set the blood rate of ECMO to 4.0 L/min, which is much higher than the usual parameter. During ECMO, coagulation factors, such as prothrombin time, activated partial thromboplastin time, and D-dimer, were examined. ECMO was maintained for 5 days without any complications; MV was stopped on the 13th day, extubated on the 24th day, and discharged from ICU on the 28th day.ConclusionECMO with non-heparin could be an optimal treatment for multitrauma patients with ARDS when traditional treatment cannot sustain oxygenation. High blood flow rate could prevent thrombosis through ongoing ECMO therapy without systemic anticoagulation. In addition, monitoring D-dimer value change (Δ D-dimer) may be better than D-dimer value in predicting clot formation in the membrane oxygenator.

The Association Between Catheter Type and Dialysis Treatment: A Retrospective Data Analysis at Two U.S.-Based ICUs.

To evaluate the association between the catheter type and multiple dialysis treatment outcomes among the critically ill. Retrospective, observational study. Two U.S.-based ICUs. Critically ill patients receiving CRRT between April 1, 2018, and July 1, 2020. A total of 1,037 CRRT sessions were analyzed. Circuit life, alarm interruption frequency (including a subset of vascular access [VA]-related alarms), termination type (elective vs nonelective), and blood flow rates. Pre- (n = 530) and post-catheter change (n = 507) periods were assessed, and the post-change period was further divided into intervals of pre-COVID (n = 167) and COVID contemporaneous (n = 340) to account for the pandemic's impact. Compared with pre-change sessions, post-change sessions had 31% longer circuit life (95% CI, 1.14-1.49; p < 0.001), 3% higher blood flow rate (1.01-1.05; p < 0.01), and lower proportion of nonelective terminations (adjusted odds ratio [OR], 0.42 [0.28-0.62]; p < 0.001). There were fewer interruptions for all alarms (adjusted count ratio, 0.95 [0.87-1.05]; p = 0.31) and VA-related alarms (0.80 [0.66-0.96]; p = 0.014). The sessions during COVID period were statistically similar to pre-COVID sessions for all outcomes except a lower proportion of nonelective terminations (adjusted OR, 0.39 [0.22-0.70]; p < 0.01). A change in catheter type was associated with longer CRRT sessions with fewer interruptions and unexpected terminations in a population of critical patients.

The Science of Extracorporeal Ultrafiltration: Introducing a Novel Miniaturized Device

Introduction: Fluid overload has been associated with untoward outcomes in a variety of clinical settings. Isolated extracorporeal ultrafiltration (UF) allows for mechanical extraction of excess fluid and optimization of volume status without the established risks associated with use of high-dose diuretics. Conventional machines for renal replacement therapy can be used to perform isolated UF. However, they typically need high blood flow rates with high circuit volumes and the therapy has to be performed by trained nurses. Herein, we describe a novel device, the Artificial Diuresis-1, or AD 1 (Medica S.p.A., Medolla, Italy), which is a portable technology designed to perform extracorporeal UF at bedside. Materials and Methods: The AD 1 uses a polysulfone mini-filter to generate ultrafiltrate with the help of two forces: blood flow (Qb) and gravity (based on the height at which the ultrafiltrate collection bag is placed). In vitro experiments were performed using human blood to evaluate vascular access pressures and ultrafiltrate volumes using various central venous catheters (CVCs; 12 Fr bilume, 10 Fr with 2 separate lumens, pediatric catheter 7 Fr). A variety of combinations were tested with Qb of 20, 35, 50 mL/min and collection bag height at 20, 40, 60 cm, measuring the UF rate per minute while monitoring the pressures in the venous and arterial lines and filtration fraction. Results: The device’s performance was as expected. Regarding the pediatric CVC, it was possible to perform measurements only with a Qb of 20 mL/min due to increased venous pressure. UF rates when lines were directly connected to the blood container as well as for CVC Tesio ranged from 3.7 to 11 mL/min, for the CVC Niagara™ from 4.5 to 12.5 mL/min, and for the CVC 7 Fr from 8.5 to 10 mL/min. The pressures of the vascular accesses were kept within a range of −5/-40 mm Hg for the artery and +10/+70 mm Hg for the vein. The highest venous pressure values were found with the CVC 7 Fr (+80/+100 mm Hg). Conclusions: This novel device allows to treat patients with fluid overload in a variety of settings, from low-intensity department such as long-term care facilities to the intensive care unit. The device is small and portable, has a simple design, and is user friendly. Future studies will be needed to evaluate whether gentle UF and treatment of volume overload will translate into improvement in clinical outcomes such as a reduction in congestion-related hospital admissions.

A tactics for treating large skin wounds on the head

An open wound on the head is an injury (skin tear) of all scalp external layers including dermis, subcutaneous fatty tissue, aponeurosis, muscles, vessels and nerves with intact skull bones and intact neurological reactions [1].Extensive wounds of the external head layers, in addition to a standard threat to the human health, bear an additional risk due to their close localization to the brain. Because of the abundant blood supply to scalp soft tissues, high rate of volumetric blood flow (50–60 milliliters per 100 g of brain tissue), numerous extra-, intracranial arterial and venous anastomoses, there is a real danger of spreading the infection inside the skull and developing meningitis or encephalitis.Problems of care of patients with extensive head wounds, risk of complications that can cause severe consequences determine the relevance of the issue presented in this work.Objective. To analyze treatment results of patients admitted to the emergency department of Mariinskaya State City Hospital in St. Petersburg within three months in 2021 and to develop an optimal tactics for treating patients with extensive wounds of the scalp.Material and research methods. 2245 patients with various types of head injury were admitted to the hospital; 610 (27.2 %) of them had damage of the external scalp layers. Each patient had standard clinical and laboratory examination and multislice computed tomography (MSCT) examination of the head at 64-slice Definition AS (Siemens, Germany) CT scanner. In the emergency department, all patients who were injured by high-energy traumatic objects had the primary surgical debridement; all patients who were injured by low-energy traumatic objects had wound toilet and wound suturing. Three most representative cases with extensive wounds of the external scalp (over 10 cm) with illustrations are presented in the article as clinical examples.Results. All patients had good outcomes. There were no any signs of wound infection either.Conclusion. A thorough primary surgical debridement of scalp wounds with their drainage followed by observation and treatment in the hospital is a necessary condition for successful healing of large scalp wounds.

Global real-world data on hemodiafiltration: An opportunity to complement clinical trial evidence.

Hemodiafiltration (HDF) is a renal replacement therapy that utilizes both diffusive clearance and convective transport to achieve greater clearance of middle-molecular-weight solutes. Among other factors, important prerequisites for the implementation of HDF include access to high-flux dialyzers, achievement of high blood flow rates, and availability of high volumes of sterile substitution/replacement fluids. Online hemodiafiltration (OL-HDF) is an established kidney replacement therapy, frequently used in many countries. Although in the United States, some prerequisites (e.g., access to high-flux dialyzers and achievement of high blood flow rates) for OL-HDF treatment are readily available; however, a machine capable of generating the online solution for OL-HDF is currently not available. As the clinical experience with HDF accumulates globally, it is worth examining the evidence for this kidney replacement therapy as used in routine clinical care. Such real-world evidence is increasingly recognized as valuable by clinicians and may inform regulatory decisions. In this review, we will focus on emerging global real-world data derived from routine clinical practices and examine how these data may complement those derived from clinical trials.

Arterial and venous thrombosis. Is the Virchow’s triad always valid?

Despite the success of conservative and surgical treatment of vascular diseases, the prevention of arterial and venous thrombosis remains extremely actual. For more than a hundred years, the so-called «Virchow’s triad» has been used to explain the mechanism of thrombosis: 1–slowing of blood flow; 2–hypercoagulation; 3 – damage to the vascular wall. However, the combination of these factors is fully applicable only for venous thrombosis and limited for arterial thrombosis. The generally accepted strategy for the prevention of venous thrombosis is the use of anticoagulants, while for arterial thrombosis – antiaggregants. In recent years the mechanisms of blood clot formation at high blood flow rates in the areas of arterial stenosis, as well as the role of platelets and von Willebrand factor in this process, were investigated. In the presented review, the details of the mechanisms of thrombosis in the arteries are analyzed and the concept of «arterial triad» is introduced. Arterial triad includes: 1 – arterial stenosis (increase in shear rate); 2 – platelets (their activation and interaction with von Willebrand factor); 3 – damage of the vascular wall. The arterial triad describes the mechanisms of thrombosis in the presence of artery stenosis (usually due to atherosclerosis). Understanding similarities and differences between Virchow’s and arterial triads, will allow us to estimate the risk factors in patients with cardiovascular pathology and develop optimal methods of their prevention.

Prescription of online hemodiafiltration (ol-HDF).

HDF prescription should be able to satisfy the delivery of an optimal dialytic convective dose. Several factors are implicated in this endeavor. High blood flow rate is crucial to warranty processing an adequate blood volume and to ensure the highest shear rate per fiber needed to cleanse and prevent membrane fouling. A highly permeable dialyzer is needed with a surface area aligned to blood flow and performance needs. Anticoagulation requires specific adaptation in case of low molecular weight heparin use. By default, HDF prescription modality should ideally start by postdilution mode with a stepwise increment of convective dose by probing patient tolerance and efficacy. Alternative substitution modality should be considered if dialytic convective dose could not be achieved in the usual time frame. Convective dose prescription relies either on a manual mode (pressure control or volume control) or on automated mode (ultrafiltration control) depending on the technical options of the HDF machines. Dialysate flow rate is regulated by the HDF machine but should preferably keep constant dialysis fluid flowing the dialyzer with a Qb:Qd ratio of 1.4. Treatment time should not be reduced with HDF prescription. Treatment time should fit with patient tolerance (hemodynamic, osmotic, and solute shifts) and overall solute removal efficiency. Electrolytic prescription does not require specific adjustments as compared with conventional dialysis, but the patient needs to be monitored regularly and dialysate electrolyte adjusted to lab tests. A stepwise approach for implementing ol-HDF is preferable depending on the initial condition of the patient. Three particular cases may be considered: late-stage chronic kidney disease patient transitioning to renal replacement therapy, stable dialysis patient switching to HDF, and unstable or fragile patient or specific treatment schedule. Optimal dosing of HDF and personalized care to ensure treatment adequacy is the main goal for renal replacement therapy to improve patient outcomes. That should be ensured with HDF treatment.

Computational Modelling of Glucose Uptake by SGLT1 and Apical GLUT2 in the Enterocyte.

It has been suggested that glucose absorption in the small intestine depends on both constitutively expressed SGLT1 and translocated GLUT2 in the brush border membrane, especially in the presence of high levels of luminal glucose. Here, we present a computational model of non-isotonic glucose uptake by small intestinal epithelial cells. The model incorporates apical uptake via SGLT1 and GLUT2, basolateral efflux into the blood via GLUT2, and cellular volume changes in response to non-isotonic conditions. The dependence of glucose absorption on luminal glucose, blood flow rate, and inlet blood glucose concentration is studied. Uptake via apical GLUT2 is found to be sensitive to all these factors. Under a range of conditions, the maximum apical GLUT2 flux is about half of the SGLT1 flux and is achieved at high luminal glucose (> 50 mM), high blood flow rates, and low inlet blood concentrations. In contrast, SGLT1 flux is less sensitive to these factors. When luminal glucose concentration is less than 10 mM, apical GLUT2 serves as an efflux pathway for glucose to move from the blood to the lumen. The model results indicate that translocation of GLUT2 from the basolateral to the apical membrane increases glucose uptake into the cell; however, the reduction of efflux capacity results in a decrease in net absorption. Recruitment of GLUT2 from a cytosolic pool elicits a 10–20% increase in absorption for luminal glucose levels in the a 20–100 mM range. Increased SGLT1 activity also leads to a roughly 20% increase in absorption. A concomitant increase in blood supply results in a larger increase in absorption. Increases in apical glucose transporter activity help to minimise cell volume changes by reducing the osmotic gradient between the cell and the lumen.

Interrelation of cognitive functions and neural networks with blood flow velocity through the internal jugular vein in patients with chronic cerebral ischemia

Understanding age-related and functional changes in cerebral venous circulation is critical for the development of new preventive, diagnostic and therapeutic approaches to maintaining brain health in the elderly. Chronic cerebral ischemia is one of the widespread socially significant vascular diseases caused by a decrease in the level of blood circulation. To assess the role of venous outflow through the internal jugular veins in cognitive decline and neural networks in patients with chronic cerebral ischemia, 30 men and 40 women (average age 66.5 years), cognitive functions and organization of neural networks were studied at high and low levels of cerebral venous blood flow through the internal jugular veins. To assess the venous outflow, the systolic blood flow rate was measured by the internal jugular veins. A higher rate of venous outflow through internal jugular veins is associated with a more successful performance of the Luria test for verbal memory. A higher or lower blood flow rate affects the formation of neural networks of the brain. At a higher blood flow rate, the predominant areas of the resting neural networks (the passive mode network of the brain and the salient network) are localized in the frontal regions, at a low blood flow rate, the predominant neural network (frontal-parietal) is located in the left hemisphere. The state of faster and slower venous outflow forms neural networks using different neural formations that affect verbal memory. Reorganization of neural networks in this case, apparently, is the central mechanism responsible for cognitive decline in chronic cerebral ischemia (2 figs, 1 table, bibliography: 10 refs)

Safety and effectiveness of high flow extracranial to intracranial saphenous vein bypass grafting in the treatment of complex intracranial aneurysms: a single-centre long-term retrospective study

BackgroundTo summarize the safety and effectiveness of high flow extracranial to intracranial saphenous vein bypass grafting in the treatment of complex intracranial aneurysms.MethodsThe data of complex intracranial aneurysms patients for high flow extracranial to intracranial saphenous vein bypass grafting from January 2008 to January 2020 were retrospectively collected and analyzed. Eighty-two patients (31 men and 51 women) with 89 aneurysms underwent 82 saphenous vein bypass grafts followed by immediate parent vessel occlusion. The aneurysm was located at the internal carotid artery, middle cerebral artery, and basilar artery in 75, 11, and 3 cases, respectively.ResultsThe patency rate of bypass grafting was 100, 100, 96.3 and 92.4% on intraoperation, on the first postoperative day, at discharge and 6 months follow-up, respectively. At discharge and 6 months follow-up, 3 and 6 patients had graft occlusions. The main postoperative complications were transient hemiparesis and hemianopsia. 3 patients died due to bypass complications and poor physical condition.ConclusionsHigh flow extracranial to intracranial saphenous vein bypass grafting is safe and effective in the treatment of complex intracranial aneurysms and the saphenous vein can meet the requirements of brain blood supply. A high rate of graft patency and adequate cerebral blood flow can be achieved.HighlightsA single-centre long-term retrospective study was conducted to assess the safety and effectiveness of high flow EC-IC saphenous vein bypass grafting in the treatment of complex intracranial aneurysms. The data of 82 patients from January 2008 to January 2020 were retrospectively collected and analysed.We found the patency rate of bypass grafting was 100, 100, 96.3 and 92.4% on intraoperation, on the first postoperative day, at discharge and 6 months follow-up, respectively. At discharge and 6 months follow-up, 3 and 6 patients had graft occlusions.Finally, we conclude that high flow extracranial to intracranial saphenous vein bypass grafting is safe and effective in the treatment of complex intracranial aneurysms and the selected blood supply vessels can meet the requirements of blood supply.As far as we know, this study is one of the maximum number of cases in the treatment of complex intracranial aneurysms with saphenous vein bypass.

Veno-venous extracorporeal blood phototherapy increases the rate of carbon monoxide (CO) elimination in CO-poisoned pigs.

Carbon monoxide (CO) inhalation is the leading cause of poison-related deaths in the United States. CO binds to hemoglobin (Hb), displaces oxygen, and reduces oxygen delivery to tissues. The optimal treatment for CO poisoning in patients with normal lung function is the administration of hyperbaric oxygen (HBO). However, hyperbaric chambers are only available in medical centers with specialized equipment, resulting in delayed therapy. Visible light dissociates CO from Hb with minimal effect on oxygen binding. In a previous study, we combined a membrane oxygenator with phototherapy at 623 nm to produce a "mini" photo-ECMO (extracorporeal membrane oxygenation) device, which improved CO elimination and survival in CO-poisoned rats. The objective of this study was to develop a larger photo-ECMO device ("maxi" photo-ECMO) and to test its ability to remove CO from a porcine model of CO poisoning. The "maxi" photo-ECMO device and the photo-ECMO system (six maxi photo-ECMO devices assembled in parallel), were tested in an in vitro circuit of CO poisoning. To assess the ability of the photo-ECMO device and the photo-ECMO system to remove CO from CO-poisoned blood in vitro, the half-life of COHb (COHb-t1/2 ), as well as the percent COHb reduction in a single blood pass through the device, were assessed. In the in vivo studies, we assessed the COHb-t1/2 in a CO-poisoned pig under three conditions: (1) While the pig breathed 100% oxygen through the endotracheal tube; (2) while the pig was connected to the photo-ECMO system with no light exposure; and (3) while the pig was connected to the photo-ECMO system, which was exposed to red light. The photo-ECMO device was able to fully oxygenate the blood after a single pass through the device. Compared to ventilation with 100% oxygen alone, illumination with red light together with 100% oxygen was twice as efficient in removing CO from blood. Changes in gas flow rates did not alter CO elimination in one pass through the device. Increases in irradiance up to 214 mW/cm2 were associated with an increased rate of CO elimination. The photo-ECMO device was effective over a range of blood flow rates and with higher blood flow rates, more CO was eliminated. A photo-ECMO system composed of six photo-ECMO devices removed CO faster from CO-poisoned blood than a single photo-ECMO device. In a CO-poisoned pig, the photo-ECMO system increased the rate of CO elimination without significantly increasing the animal's body temperature or causing hemodynamic instability. In this study, we developed a photo-ECMO system and demonstrated its ability to remove CO from CO-poisoned 45-kg pigs. Technical modifications of the photo-ECMO system, including the development of a compact, portable device, will permit treatment of patients with CO poisoning at the scene of their poisoning, during transit to a local emergency room, and in hospitals that lack HBO facilities.

The efficiency of continuous renal replacement therapy for rewarming of patients in accidental hypothermia--An experimental study.

Severe accidental hypothermia carries high mortality and morbidity and is often treated with invasive extracorporeal methods. Continuous veno-venous hemodiafiltration (CVVHDF) is widely available in intensive care units. We sought to provide theoretical basis for CVVHDF use in rewarming of hypothermic patients. CVVHDF system was used in the laboratory setting. Heat balance and transferred heat units were evaluated for the system without using blood. We used 5L of crystalloid solution at the temperature of approximately 25°C, placed in a thermally insulated tank (representing the "central compartment" of a hypothermic patient). Time of warming the central compartment from 24.9 to 30.0°C was assessed with different flow combinations: "blood" (central compartment fluid) 50 or 100 or 150mL/min, dialysate solution 100 or 1500mL/h, and substitution fluid 0 or 500mL/h. The total circulation time was 1535minutes. There were no differences between heat gain values on the filter depending on blood flow (P=.53) or dialysate flow (P=.2). The mean heating time for "blood" flow rates 50, 100, and 150mL/min was 113.7minutes (95% CI, 104.9-122.6minutes), 83.3minutes (95% CI, 76.2-90.3minutes), and 74.7minutes (95% CI, 62.6-86.9minutes), respectively (P<.01). The respective median rewarming rate for different "blood" flows was 3.6°C/h (IQR, 3.0-4.2°C/h), 4.8 (IQR, 4.2-5.4°C/h), and 5.4 (IQR, 4.8-6.0°C/h), respectively (P<.01). The dialysate flow did not affect the warming rate. Based on our experimental model, CVVHDF may be used for extracorporeal rewarming, with the rewarming rates increasing achieved with higher blood flow rates.

Therapeutic Plasma Exchange with Continuous Renal Replacement Therapy for Pediatric Acute Liver Failure: A Case Series from Thailand

Aim and objectivePediatric acute liver failure (PALF) is a life-threatening condition. Extracorporeal support has been applied for toxic metabolite clearance and serves as a bridging therapy to liver transplantation (LT) or to the regeneration of the liver, but evidence for treatment approaches is still lacking in the pediatric population. We aim to report our experience on therapeutic plasma exchange with high-volume continuous renal replacement therapy (TPE + HV-CRRT) as a promising supportive treatment for PALF.Materials and methodsA total of eight PALF cases aged 9 months to 14 years, weighing 10–50 kg., who were admitted to PICU King Chulalongkorn Memorial Hospital, Thailand and treated with TPE + HV-CRRT from January 2016 to September 2019 were reviewed. Patient demographic data, indications, technical aspects, and clinical outcomes were recorded.ResultsAll patients who underwent TPE + HV-CRRT showed clinical improvement regarding serum bilirubin levels and coagulation studies after the therapy. Complications from the therapy were hemodynamic instability, symptomatic fluid overload, and bleeding from catheter sites. Among these, 6 (75%) patients survived with 4 (50%) successful LTs and 2 (25%) spontaneous recovery. Two children (25%) died while on the transplantation list.ConclusionTPE + HV-CRRT can be used safely as a bridging therapy in children with PALF. As opposed to the adult population, higher volume of TPE or higher blood flow rate in pediatric patients might associate with hemodynamic instability during the procedure.How to cite this articleTrepatchayakorn S, Chaijitraruch N, Chongsrisawat V, Chanakul A, Kongkiattikul L, Samransamruajkit R. Therapeutic Plasma Exchange with Continuous Renal Replacement Therapy for Pediatric Acute Liver Failure: A Case Series from Thailand. Indian J Crit Care Med 2021;25(7):812–816.