Spectral characterization of intraoperative renal perfusion using hyperspectral imaging and artificial intelligence.

Accurate intraoperative assessment of organ perfusion is a pivotal determinant in preserving organ function e.g. during kidney surgery including partial nephrectomy or kidney transplantation. Hyperspectral imaging (HSI) has great potential to objectively describe and quantify this perfusion as opposed to conventional surrogate techniques such as ultrasound flowmeter, indocyanine green or the subjective eye of the surgeon. An established live porcine model under general anesthesia received median laparotomy and renal mobilization. Different scenarios that were measured using HSI were (1) complete, (2) gradual and (3) partial malperfusion. The differences in spectral reflectance as well as HSI oxygenation (StO2) between different perfusion states were compelling and as high as 56.9% with 70.3% (± 11.0%) for "physiological" vs. 13.4% (± 3.1%) for "venous congestion". A machine learning (ML) algorithm was able to distinguish between these perfusion states with a balanced prediction accuracy of 97.8%. Data from this porcine study including 1300 recordings across 57 individuals was compared to a human dataset of 104 recordings across 17 individuals suggesting clinical transferability. Therefore, HSI is a highly promising tool for intraoperative microvascular evaluation of perfusion states with great advantages over existing surrogate techniques. Clinical trials are required to prove patient benefit.

Influence of Aortic Arch Morphology on Renal Perfusion in Patients with Coarctation of the Aorta: An Exploratory Study.

Objectives: The configuration of the aortic arch, particularly a Gothic arch shape, in individuals with corrected coarctation of the aorta (CoA) has been associated with a decreased systolic wave amplitude across the arch, which could potentially impair renal perfusion and elevate the risk of arterial hypertension. This study aims to explore the relationship between the morphological characteristics of the aortic arch and their impact on renal perfusion in patients with CoA. Methods: Seventy-one subjects with corrected CoA underwent continuous 24 h ambulatory blood pressure monitoring, computed tomography to assess the aortic arch, and renal perfusion scanning. Subjects were stratified into three groups based on the height-to-width (H/W) ratio of their aortic arch: Group 1 with a H/W ratio of <0.65, Group 2 with a H/W ratio between 0.65 and 0.85, and Group 3 with a H/W ratio of >0.85. Results: Groups 1 and 2 (53,78% and 62.63%) presented with a higher hypertension prevalence of elevated blood pressure than Group 3 (38.89%). Notable variations were observed among the subjects in the time to peak perfusion (Tmax) in the left kidney across the groups. Group 1 showed a median Tmax at 0.27, Group 2 at 0.13, and Group 3 at -0.38 (p-value = 0.079). The differences in Tmax for the right kidney followed a similar trend but were not statistically significant (Group 1 at 0.61, Group 2 at 0.22, and Group 3 at 0.11; p-value = 0.229). Conclusions: This study suggests that variations in the aortic arch morphology might not significantly influence renal perfusion in CoA patients. This indicates the potential adaptability of the renal blood flow, which appears to compensate for reduced perfusion, thus minimizing adverse effects on the kidney function. This adaptability suggests an inherent physiological resilience, emphasizing the need for further targeted research to understand the specific interactions and impacts on treatment strategies for CoA.

Periods of low renal perfusion pressure are associated with acute kidney injury following paediatric cardiac surgery.

INTRODUCTION: Acute kidney injury is associated with worse outcomes after cardiac surgery. The haemodynamic goals to ameliorate kidney injury are not clear. Low post-operative renal perfusion pressure has been associated with acute kidney injury in adults. Inadequate oxygen delivery may also cause kidney injury. This study evaluates pressure and oximetric haemodynamics after paediatric cardiac surgery and their association with acute kidney injury. MATERIALS AND METHODS: Retrospective case-control study at a children's hospital. Patients were < 6 months of age who underwent a Society of Thoracic Surgery-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery categories ≥ 3. Low renal perfusion pressure was time and depth below several tested thresholds. The primary outcome was serum creatine-defined acute kidney injury in the first 7 days. RESULTS: Sixty-six patients (median age 8 days) were included. Acute kidney injury occurred in 36%. The time and depth of renal perfusion pressure < 42 mmHg in the first 24 hours was greater in acute kidney injury patients (94 versus 35 mmHg*minutes of low renal perfusion pressure/hour, p = 0.008). In the multivariable model, renal perfusion pressure < 42 mmHg was associated with acute kidney injury (aOR: 2.07, 95%CI: 1.25-3.82, p = 0.009). Mean arterial pressure, central venous pressure, and measures of inadequate oxygen delivery were not associated with acute kidney injury. CONCLUSION: Periods of low renal perfusion pressure (<42 mmHg) in the first 24 post-operative hours are associated with acute kidney injury. Renal perfusion pressure is a potential modifiable target that may mitigate the impact of acute kidney injury after paediatric cardiac surgery.

Dynamic rubidium-82 PET/CT as a novel tool for quantifying hemodynamic differences in renal blood flow using a one-tissue compartment model.

PURPOSE: Assessing renal perfusion in-vivo is challenging and quantitative information regarding renal hemodynamics is hardly incorporated in medical decision-making while abnormal renal hemodynamics might play a crucial role in the onset and progression of renal disease. Combining physiological stimuli with rubidium-82 positron emission tomography/computed tomography (82Rb PET/CT) offers opportunities to test the kidney perfusion under various conditions. The aim of this study is: (1) to investigate the application of a one-tissue compartment model for measuring renal hemodynamics with dynamic 82Rb PET/CT imaging, and (2) to evaluate whether dynamic PET/CT is sensitive to detect differences in renal hemodynamics in stress conditions compared to resting state. METHODS: A one-tissue compartment model for the kidney was applied to cardiac 82Rb PET/CT scans that were obtained for ischemia detection as part of clinical care. Retrospective data, collected from 17 patients undergoing dynamic myocardial 82Rb PET/CT imaging in rest, were used to evaluate various CT-based volumes of interest (VOIs) of the kidney. Subsequently, retrospective data, collected from 10 patients (five impaired kidney functions and five controls) undergoing dynamic myocardial 82Rb PET/CT imaging, were used to evaluate image-derived input functions (IDIFs), PET-based VOIs of the kidney, extraction fractions, and whether dynamic 82Rb PET/CT can measure renal hemodynamics differences using the renal blood flow (RBF) values in rest and after exposure to adenosine pharmacological stress. RESULTS: The delivery rate (K1) values showed no significant (p = 0.14) difference between the mean standard deviation (SD) K1 values using one CT-based VOI and the use of two, three, and four CT-based VOIs, respectively 2.01(0.32), 1.90(0.40), 1.93(0.39), and 1.94(0.40) mL/min/mL. The ratio between RBF in rest and RBF in pharmacological stress for the controls were overall significantly lower compared to the impaired kidney function group for both PET-based delineation methods (region growing and iso-contouring), with the smallest median interquartile range (IQR) of 0.40(0.28-0.66) and 0.96(0.62-1.15), respectively (p < 0.05). The K1 of the impaired kidney function group were close to 1.0 mL/min/mL. CONCLUSIONS: This study demonstrated that obtaining renal K1 and RBF values using 82Rb PET/CT was feasible using a one-tissue compartment model. Applying iso-contouring as the PET-based VOI of the kidney and using AA as an IDIF is suggested for consideration in further studies. Dynamic 82Rb PET/CT imaging showed significant differences in renal hemodynamics in rest compared to when exposed to adenosine. This indicates that dynamic 82Rb PET/CT has potential to detect differences in renal hemodynamics in stress conditions compared to the resting state, and might be useful as a novel diagnostic tool for assessing renal perfusion.

Kidney Doppler Ultrasonography in Critical Care Nephrology.

Color pulsed-wave Doppler ultrasound (CPWD-US) emerges as a pivotal tool in intensive care units (ICUs) for diagnosing acute kidney injury (AKI) swiftly and non-invasively. Its bedside accessibility allows for rapid assessments, making it a primary imaging modality for AKI characterization. Furthermore, CPWD-US serves as a guiding instrument for key diagnostic-interventional procedures such as renal needle biopsy and percutaneous nephrostomy, while also facilitating therapy response monitoring and AKI progression tracking. This review shifts focus towards the integration of renal ultrasound into ICU workflows, offering contemporary insights into its utilization through a diagnostic-standard-oriented approach. By presenting a flow chart, this review aims to provide practical guidance on the appropriate use of point-of-care ultrasound (POC-US) in critical care scenarios, enhancing diagnostic precision, patient management, and safety, albeit amidst a backdrop of limited evidence regarding long-term outcomes.

Transmission of high arterial pressure into renal microvessels during venous-clamping augments ischaemia/reperfusion-induced acute kidney injury in anaesthetized rats.

AIM: In two recent studies, we observed that a 30-min renal vein clamping caused formation of interstitial haemorrhagic congestion in ischaemic and ischaemic/reperfused kidney along with the development of severer acute kidney injury (AKI) than renal artery or pedicle clamping. It was suggested that the transmission of high arterial pressure into renal microvessels during vein occlusion probably causes the occurrence of interstitial haemorrhagic congestion that augments AKI. The present investigation aimed to evaluate this suggestion by reducing renal perfusion pressure (RPP) during renal venous occlusion. METHODS: Anaesthetized male Sprague-Dawley rats were divided into three groups (n = 8), which underwent a 2-h reperfusion period following 30-min bilateral renal venous clamping along with reduced RPP (VIR-rRPP group) or without reduced RPP (VIR group) and an equivalent period after sham-operation (Sham group). RESULTS: The VIR-rRPP group compared with VIR group had lower levels of kidney malondialdehyde and tissue damages as epithelial injuries of proximal tubule and thick ascending limb, vascular congestion, intratubular cast and oedema, along with the less reductions in renal blood flow, creatinine clearance, Na+ -reabsorption, K+ and urea excretion, urine osmolality and free-water reabsorption. Importantly, the formation of intensive interstitial haemorrhagic congestion in the VIR group was not observed in the VIR-rRPP group. CONCLUSION: These results indicate that the transmission of high arterial pressure into renal microvessels during venous occlusion leads to rupturing of their walls and the formation of interstitial haemorrhagic congestion, which has an augmenting impact on ischaemia/reperfusion-induced renal structural damages and haemodynamic, excretory and urine-concentrating dysfunctions.

Re-understanding of the clinical application value of dopamine in kidney transplantation / 器官移植

Dopamine is the precursor of biosynthesis of norepinephrine. Low-dose dopamine mainly excites dopamine receptors, which may dilate renal and mesenteric vessels, increase renal blood flow and improve the microcirculation. In recent years, low-dose dopamine has been widely applied in the field of kidney transplantation due to its vasoactive effect. However, with the development of evidence-based medicine, the role of dopamine in protecting the perfusion function of renal allograft in kidney transplantation has been questioned. Multiple studies have shown that dopamine brings no significant benefit to renal and cardiac function in kidney transplantation, exerts low pressor effect, and may even increase the risk of perioperative complications. Norepinephrine may be used as a safe substitute. In this article, recent progress in the effect of dopamine upon renal and cardiac function and hemodynamics during kidney transplantation was reviewed, aiming to provide reference for clinical application of dopamine in kidney transplantation.

Renal elasticity and perfusion changes on ultrasonography in an early-stage diabetic rat model.

Background: Renal hemodynamic changes in early diabetes occur before the onset of significant structural abnormalities or clinical manifestations, and timely detection of these changes has clinical significance. This study aimed to evaluate renal elasticity and perfusion changes in an early-stage diabetic rat model by shear wave elastography (SWE) and contrast-enhanced ultrasound (CEUS), and to explore the potential correlations between renal elasticity and perfusion parameters. Methods: A total of 18 male Sprague-Dawley rats were randomly divided into three groups: a control group (group 1, n=6), a diabetic group (group 2, n=6), and a diabetic group receiving drug therapy (group 3, n=6). An intraperitoneal injection of streptozotocin (STZ) for 2 days combined with a high-fat diet (HFD) was used as the early-stage diabetic rat model. The diabetic rats in group 3 were treated with canagliflozin and losartan for 6 weeks, whereas the rats in groups 1 and 2 were given equal amounts of purified water. Renal stiffness on SWE and perfusion parameters on CEUS were measured and compared among the three groups, then the rats were sacrificed, and serum, urine, and renal histopathology were evaluated to confirm the development of early diabetes. Results: The early-stage diabetic rats without significant pathological changes exhibited bigger kidneys and higher blood glucose (all P<0.05). Among the CEUS parameters, peak enhancement (PE), wash-in area under the curve (WiAUC), wash-in perfusion index (WiPI), wash-out AUC (WoAUC), wash-in and wash-out AUC (WiWoAUC), rise time (RT), and time to peak (TTP) of diabetic rats in group 2 were significantly increased (all P<0.05), and the hyperperfusion ameliorated significantly after drug treatment. The renal elasticity measured by SWE varied in accordance with certain perfusion parameters, and was strongly positively correlated with WiAUC (r=0.701, P<0.001), WoAUC (r=0.647, P<0.001), and WiWoAUC (r=0.655, P<0.001), and moderately positively correlated with PE (r=0.539, P=0.001), WiPI (r=0.555, P<0.001), RT (r=0.425, P=0.010), and TTP (r=0.439, P=0.007). Conclusions: Renal elasticity and perfusion changes in the early stage of diabetes, and renal elasticity was positively associated with delayed and increased perfusion.

Renal Function Improvement after Aortic Valve Replacement in a Patient with Chronic Kidney Disease - A Case Report.

Inadequate peripheral perfusion due to cardiac diseases can worsen renal function in patients with chronic kidney disease (CKD). Due to the nature of the simultaneous cardiac and renal disease, it is often difficult to determine which is the primary cause, and hence many surgeons hesitate to operate on patients with end-stage kidney disease. However, when the primary cause is cardiac related, renal function can improve after successful cardiac surgery. Here, we describe a 55-year-old female patient with CKD Stage 5 who was on maintenance hemodialysis with severe aortic stenosis (AS) and underwent surgical aortic valve replacement and recovered from dialysis-dependent kidney disease. Drastic improvement in renal function after cardiac surgery can occur even in patients with CKD due to improved renal perfusion, especially in cases of AS. Therefore, diagnosing the primary cause of renal dysfunction is essential.

Application of Contrast-enhanced Ultrasound in Evaluation of Renal Function for Patients with Spinal Cord Injury Complicated with Hydronephrosis / 中国康复理论与实践

Objective:To apply contrast-enhanced ultrasound in renal function evaluation for patients with spinal cord injury complicated with hydronephrosis. Methods:From October, 2015 to November, 2018, 23 patients with spinal cord injury complicated with hydronephrosis and renal disfunction (spinal cord injury group) and 19 cases of normal kidneys (control group) accepted contrast-enhanced ultrasonography and the image was analyzed with software. The region of interest (ROI) in the renal cortex, and the time intensity curve was drawn. Logistic regression was performed with time to initial peak (TTP), peak intensity (DPI), slope of ascending time (A), area under the curve (AUC) as the independent variable and renography as the dependent variable. The data was analyzed with ROC. Results:There was no significant difference in serum creatinine and ureophil between two groups (P > 0.05). TTP was longer (t = 5.068, P < 0.001), and A and AUC were lower (t > 3.784, P < 0.01) in the spinal cord injury group than in the control group. AUC was the factor related to renography (P < 0.01). The smaller the AUC was, the greater the likelihood of kidney damage was. The sum of sensitivity and specificity was 1.759 and the corresponding AUC was 982.518 dBS. Conclusion:Contrast-enhanced ultrasound can evaluate renal function of patients with spinal cord injury complicated with hydronephrosis. The decrease in AUC of the time-intensity curve indicates that the renal function is impaired.

Variables hemodinámicas y desenlace de la función renal en pacientes de terapia intensiva / Haemodynamic variables and outcomes of renal function on intensive care patients / Variáveis hemodinâmicas e resultados da função renal em pacientes de terapia intensiva

Resumen: Introducción: Las variables hemodinámicas nos informan sobre la progresión de lesión renal aguda (AKI por sus siglas en inglés). Material y métodos: Estudio prospectivo, observacional, longitudinal, de pacientes ingresados a la Unidad de Terapia Intensiva del 2017 al 2018. Se incluyeron mayores de 18 años, con lesión renal aguda (AKI 1 o 2), monitoreo hemodinámico de tensión arterial media (TAM), tensión arterial diastólica (PAD), frecuencia cardiaca (FC) y de presión venosa central (PVC). Determinados desde las 24 horas del diagnóstico hasta el egreso. Resultados: Fueron 164 pacientes, 105 (64%) presentaron progresión de AKI cuando TAM < 75.98 mmHg. PAD < 61, PVC >8 cm H2O, FC > 90 x', TAM-PVC < 67.64 mmHg, PAD-PVC < 53.28 mmHg. Conclusiones: La TAM, PAD y la PVC tienen el mayor impacto en el riesgo de progresión de AKI cuando se calcula la presión de perfusión media con estas variables.

Abstract: Introduction: Haemodynamic variables inform us about the progression of acute kidney injury (AKI). Material and methods: Prospective, observational and longitudinal study of patients admitted to Intensive Care (ICU) from 2017-2018. patients over 18 years were included, with acute kidney injury (AKI 1, 2), and hemodynamic monitoring of mean arterial blood pressure (MAP), diastolic blood pressure (DBP), heart rate (HR) and central venous pressure (CVP). Determined from 24 hours after diagnosis and its evolution was recorded until discharge. Results: A total of 164 patients were included, progression of AKI presented when MAP < 75.98 mmHg, DBP < 61 mmHg, CVP < 8 cmH2O, FC 90 x', MAP-CVP 67.64 mmHg, DBP-CVP 53.28 mmHg, HR > 90 beats/minute. Conclusions: MAP, DBP and CVP have the greatest impact on the risk of AKI progression, especially when the mean perfusion pressure (PPM) is calculated with these two variables.

Resumo: Introdução: As variáveis hemodinâmicas informam sobre a progressão da lesão renal aguda (LRA). Materiais e métodos: Estudo prospectivo, observacional, longitudinal de pacientes admitidos em terapia intensiva (UTI) de 2017-2018. Foram incluídos pacientes maiores de 18 anos, com lesão renal aguda (LRA 1 ou 2), monitorização hemodinâmica da pressão arterial média (TAM), pressão arterial diastólica (PAD), freqüência cardíaca (FC) e pressão venosa central (PVC). Determinada a partir de 24 horas de diagnóstico até a alta. Resultados: 164 pacientes (p), 105 p (64%) apresentaram progressão da LRA quando TAM < 75.98 mmHg, PAD < 61 mmHg, PVC > 8 cmH2O, FC > 90 x´, TAM-PVC < 67.64 mmHg, PAD- PVC < 53.28 mmHg. Conclusões: TAM, PAD e PVC têm o maior impacto no risco de progressão da LRA quando a pressão média de perfusão (PMP) é calculada com essas variáveis.

Effects of Norepinephrine Combined with Dobutamine on Hemodynamics, Blood Lactic Acid, CCr, FEH2O and FENa of Patients with Septic Shock / 现代生物医学进展

Objective:To explore the effects of norepinephrine combined with dobutamine on the hemodynamics,blood lactic acid,creatinine clearance rate (CCr),fractional excretion ofH2O (FEH2O) and fractional excretion of sodium (FENa) of patients with septic shock.Methods:120 cases of patients with septic shock from January 2016 to December 2016 were selected as the research objectives and randomly divided into two groups with 60 cases in each group.Dobutamine was given to both groups,then norepinephrine was additionally given to the observation group,dopamine was additionally given to the control group.The clinical effect,changes of hemodynamics,blood lactic acid,CCr,FEH2O and FENa levels before and after treatment were compared between two groups.Results:The blood lactic acid and FENa levels of both groups were gradually decreased at 6,12,24 and 48 hours after treatment and were significantly lower than those before treatment;the CCr and FEH2O levels were gradually increased and significantly higher than those before treatment (P＜0.01).The blood lactic acid and FENa levels were gradually decreased at 6,12,24 and 48 hours after treatment and were significantly lower than those of the control group at same time (P＜0.01),the FEH2O level was significantly higher than that of the control group at the same time (P＜0.01).The MAP,SVRI of both groups at 6,12,24 and 48 hours after treatment were significantly higher than those before treatment,but the CI at 24,48 hours after treatment were significantly higher than those before treatment (P＜0.01),the MAP of observation group at 6,12,24 and 48 hours after treatment were significantly lower than those before treatment (P＜0.01),the MAP at 6,12 hours after treatment were significantly higher than those before treatment (P＜0.01),the HR of observation group at 6,12,24 and 48 hours after treatment were significantly lower than those of the control group,but SVRI was significantly higher than those of the control group (P＜0.01).The mortality of observation group was 18.33％ at 28th days after treatment,which was 35.00％ in the control group and significantly higher than that of the observation group (P＜0.05).Conclusion:Norepinephrine combined with dobutamine could improve the hemodynamics,reduce the blood lactate level,improve the renal perfusion and prognosis of patients with septic shock.

Quantitative analysis of renal injury using CEUS in hypertensive rabbits model induced by L-NAME / 天津医药

Objective To assess the value of contrast-enhanced ultrasound (CEUS) on quantitative analysis of re?nal cortex perfusion in hypertensive rabbits model. Methods Hypertensive rabbit modal (n=10) were established by inject?ing N-nitro-L-arginin methylester (L-NAME). CEUS and Cystatin C (CysC) serum level analysis were performed at differ?ent time points:before and the 2nd, 4th, 6th and 8th week after injecting L-NAME. Time-intensity curve and area under curve (AUC) were analyzed quantatively while correlation of AUC and CysC were also analyzed. Results Serum level of Cys C in?creased significantly at the 6th week after L-NAME administration which is earlier than the increase of serum levels of Scr and BUN. AUC decreased at first then increased after L-NAME administration. Upon addition of L-NAME, rise time (RT) and peak intensity (PI) decreased while mean transit time (MTT), time from peak to one half (HPT) and time to peak (TTP) in?creased. Our study confirmed a positive correlation between AUC and Cys C (r=0.950, P<0.001). Conclusion Setting up rabbits model by L-NAME is convenient and reproducible, which is an useful tool in experimental study of preclinical and clinical phase of hypertensive renal injury. CEUS combining with CysC serum level analysis is considered as an effective technology for evaluating renal function in hypertensive patients.

Validação conceitual e clínica do diagnóstico de enfermagem "risco de perfusão renal ineficaz" em transplantados de células tronco hematopoéticas / The nursing diagnosis of

O transplante de células tronco hematopoéticas é uma modalidade terapêutica para o tratamento de doenças oncológicas, hematológicas e congênitas. Este é complexo e pode implicar em complicações como a toxicidade renal. Para esses pacientes, o diagnóstico de enfermagem de risco de perfusão renal ineficaz é estabelecido, porém pouco estudado. Questiona-se se os fatores de risco relacionados na NANDA Internacional para o referido diagnóstico podem ser identificados e se são válidos para pacientes submetidos a este tipo de transplante. O presente estudo teve por objetivo geral validar o diagnóstico de enfermagem de “Risco de Perfusão Renal Ineficaz” em pacientes submetidos ao transplante de células tronco hematopoéticas. Como objetivos específicos foram estabelecidos: definir o conceito de perfusão renal ineficaz; buscar medidas padrão ouro na determinação de perfusão renal ineficaz; identificar fatores de risco para o desenvolvimento deste diagnóstico em pacientes submetidos ao transplante; propor modelo de predição de risco de desenvolvimento de perfusão renal ineficaz. O estudo foi conduzido em duas etapas metodológicas: revisão integrativa da literatura e validação clínica por meio de uma coorte histórica. Na revisão integrativa foram consultadas as bases de dados MEDLINE, LILACS, CINAHL e Biblioteca Cochrane. A amostra constitui-se de 30 estudos avaliados quanto ao tipo, local de publicação, língua utilizada e nível de evidência utilizando instrumento estruturado. A coorte histórica foi realizada em uma amostra de 216 prontuários de pacientes transplantados. Os dados foram submetidos à análise descritiva, univariada e multivariada. Na validação conceitual estabeleceu-se o conceito, identificação e fatores de risco de perfusão renal ineficaz a partir de publicações de nível de evidência grau III e VI. Para a validação clínica conduziu-se estudo nos prontuários de pacientes de modo a identificar os fatores de contribuintes para o risco de perfusão...

The hematopoietic stem cell transplantation is a therapeutic modality for the treatment of malignancies, and hematologic defects. It is full of complexity and may offer complications such as renal toxicity. For these patients, the nursing diagnosis of riskfor ineffective renal perfusion is established, but little studied specially related to risk factors listed in NANDA International and its identification and validity for patients undergoing to this type of transplantation. This study aimed to validated the nursing diagnosis of "Risk of Renal Perfusion Ineffective" with patients undergoing to hematopoietic stem cell transplantation. The specific goals established that define the concept of renal perfusion ineffective; for seek gold standard measures for determining ineffective renal perfusion; established to identify risk factors for the problem development in patients undergoing to transplantation and risk factors study and to propose a model for predicting the risk of ineffective renal perfusion. The study was conducted in two stages: an integrative literature review and clinical validation using a historical cohort. The databases MEDLINE, LILACS, CINAHL and the Cochrane Library were consulted for the integrative review. The sample consisted of 30 studies evaluated by the type, country, language and level of evidence using a structured instrument. A historical cohort study was conducted in 216transplant patients records. The data were submitted to descriptive, univariate and multivariate analysis. The concept of ineffective renal perfusion and the identification of the risk factors were established by the conceptual validation from publications level of evidence grade III and VI. Clinical validation was conducted in patient’s records in order to identify thefactors contributing to the risk of renal perfusion ineffective. The risk of ineffective renal perfusion was present in 54/216 patients (25%) and the normal renal function occurred...

Triplex Doppler da artéria renal e a relação entre a ecobiometria dos rins com distância atlanto-coccígea e altura em Canis familiaris / Renal artery Triplex Doppler and the relationship between kidney ecobiometry with atlanto-coccyges distance (ACD) and height (H) in Canis familiaris

O objetivo do trabalho foi estabelecer a relação entre a ecobiometria renal com medidas de conformação corporal como a distância atlanto-coccígea (DAC) e a altura (H) de cães adultos saudáveis, obtendo-se parâmetros de normalidade para avaliar o tamanho e volume renal, bem como estabelecer valores de referência para avaliar a perfusão sanguínea dos rins por meio do índice de resistividade (IR) e do índice de pulsatilidade (IP) do ramo principal da artéria renal. No estudo foram utilizados 22 cães adultos sem raça definida, sendo 11 machos e 11 fêmeas. Os animais foram previamente aferidos quanto a DAC e a H. Os exames ultra-sonográficos foram realizados com um aparelho HDI 4000 PHILIPS munido de um transdutor microconvexo multifreqüêncial (5-8 MHz), dispositivos Doppler Colorido e Doppler de Fluxo. Os animais foram posicionados em decúbito lateral direito ou esquerdo, de acordo com o rim a ser avaliado. Os diâmetros longitudinal (DL) e dorsoventral (DDV) dos rins foram mensurados na secção longitudinal e, o diâmetro transversal (DT) foi aferido no plano transversal. O volume (V) foi calculado automaticamente pelo software do ultra-som. Com o uso do Triplex Doppler, o IR e o IP das artérias renais direita e esquerda foram obtidos. Todos os dados foram apresentados em média ± EPM. Análises de regressão linear foram realizadas tendo o DL, DDV, DT e V como variáveis dependentes e a DAC e H como variáveis independentes. Os IR e IP dos rins direito e esquerdo foram comparados pelo teste t de Student. A DAC variou de 54-78cm para machos e 37-71cm para fêmeas e a altura variou entre 34-64 cm para os machos e 24-57cm para as fêmeas. As médias obtidas para DL, DDV, DT e V dos rins esquerdo e direito foram: 5,24±0,27cm, 3,07±0,15cm, 3,07±0,9cm, 28,01±3,4mL e 4,50±0,19cm, 2,88±0,14cm, 2,71±0,15cm, 21,27±2,6mL, respectivamente. As análises de regressão linear entre as medidas lineares e volume renal com a DAC e a H foram significativas para os interceptos ...

The aim of this paper was to establish the relation between the kidney ecobiometry with atlanto-coccyges distance (ACD) and height (H) in adult healthy dogs, to obtain normality parameters for assessment of renal size and volume, as well as establish reference values to evaluate kidney blood perfusion by the resistivity index (RI) and pulsatility index (PI) of main renal artery. The study was applied at 22 adult dogs, 11 males and 11 females. Previously, the DAC and H of all animals were measured. For ultrasonographic examination, the ultra-sound system HDI 4000 PHILIPS equipped with a multi-frequency microconvex transducer, Color Doppler and Spectral Doppler devices was used. The animals were placed into right or left lateral decubitus position, in agreement with the kidney to be assessed. The longitudinal (LD) and dorsoventral diameters (DVD) of kidney were measured in longitudinal plane, and the transverse diameter (TD) was determined in transversal section. The renal volume (V) was automatically calculated by the ultrasound software. With Triplex Doppler, the RI and PI of right and left main renal arteries were obtained. All data were represented in mean ± SEM. Linear regression analyses were performed with renal LD, DVD, TD and V as dependent variable, and ACD and H as independent variable. RI and PI were compared between right and left renal arteries with Student's t-test. The LD, DVD, TD (cm) and V (ml) mean measurements for the left and right kidneys were: 5.24±0.27, 3.07±0.15, 3.07±0.9, 28.01±3.4 and 4.50±0.19, 2.88±0.14, 2.71±0.15, 21.27±2.6. All regression analyses were significant for the intercept and regression coefficient (P<0.01). There were statistical differences on RI and PI means between right and left renal arteries (P=0.001). The RI and PI means of left and right renal artery obtained were: 0.62±0.08 and 1.34±0.18; 0.70±0.06 and 1.62±0.13. The data obtained in the present paper can be used as parameters for evaluation ...

The Systemic Hemodynamic and Renal Effects of Nicardipine Administration Followed by Supraceliac Aortic Cross Clamping and Unclamping in Experimental Dogs / 대한마취과학회지

BACKGROUND: The incidence of renal insufficiency is reported about 18-27% during the thoracoabdominal aneurysm surgery. The possible mechanisms are reduction and maldistribution of renal blood flow, activation of renin angiotensin system, release of various mediators. In this study, we observed the effect of nicardipine, one of the calcium channel blockers that commonly used, on the systemic hemodynamics and the renal fuctions. METHODS: A total of 13 mongrel dogs were divided into two groups: control group (C, n = 7), nicardipine administration group (N, n = 6). After brachial arterial and Swan-Ganz catheterization, midline abdominal incision was made. For the aortic cross clamping the supraceilac aorta was exposed and the doppler flowmeter probe was placed on the left renal artery. The thermal diffusion microprobe was inserted in the renal parenchyme to measure local renal perfusion. At sixty minutes after aortic cross clamping, systemic hemodynamic data, renal blood flow and local renal perfusion were measured and at 1, 2, 3, 4, 5 and 6 hours after unclamping the same parameters were measured. RESULTS: There were no differences on renal blood flow, renal perfusion and oxygen extraction ratio between two groups. The renal blood flow and renal perfusion did not recover to the baseline level after unclamping in both groups. The plasma renin activity, serum creatinine concentration and cystatin-c did not show any difference between groups respectively. CONCLUSIONS: We concluded that the administration of nicardipine after supraceliac aortic unclamping to improve the renal function was not effective in experimental dogs.

Studies on the Change in Renal Functions after an Occlusion of Blood Supply and Perfusion of the Kidney in Dog / 대한비뇨기과학회지

It is generally known that the renal function is significantly decreased immediately after renal transplantation. However, there is no literature concerning the influence of vascular factor such as thrombus formation and narrowing of the vascular lumen due to its anastomosis on the renal functions following kidney transplantation. As an attempt to dissociate the effect of vascular factors from the immediate functional capacity after transplantation. the author studied the various renal function after clamping the renal artery and perfusing the kidney for 45 minutes while avoiding injury to the renal pedicle as much as possible. Then the recovery pattern of renal function was observed for 2 weeks. In every phase of the experiment (immediately, 1,3,7, and 14 days after the clamping and perfusion) various renal functions of the experimental kidney (left kidney) were compared with that of the normal kidney (right kidney). The results are summarized briefly as follows: 1. Hemodynamic changes such as glomerular filtration rate and renal plasma flow were decreased to approximately 65~75% of the control kidney by 7 days after the experiment and then recovered to the values of the normal kidney. 2. Tubular reabsorption of water and electrolytes were reduced in the experimental kidney until the 7th day after the procedures, but these decreases were improved to nearly normal 2 weeks after the renal artery clamping and perfusion. This reduction of tubular reabsorption capacity is considered to be brought by ischemia-induced tubular damage 3. The extraction ratio of PAH was significantly dropped to about 50% of the normal at 3 days after the experiment, then it recovered almost to normal at 14 days after the procedures. In addition total renal plasma flow calculated from C(pah)/E(pah) was almost identical in both kidneys except in the 3 days group which showed a significant increase in the experimental kidney. This finding suggested that postocclusive reactive hyperemia developed. 4. The above mentioned results showed that renal functions after renal artery clamping and perfusion of the kidney with cold (4 degrees C) solution were decreased significantly by the 7th followed with almost normal recovery 2 weeks after the experiment. It was suggested that the period of recovery of renal function was shortened by cold perfusion of the kidney, and day and vascular factors did not influence significantly on the decrease in renal functions after renal transplantation.