Urinary oxygen tension: a clinical window on the health of the renal medulla?

2014 ◽  
Vol 306 (1) ◽  
pp. R45-R50 ◽  
Author(s):  
Roger G. Evans ◽  
Julian A. Smith ◽  
Christopher Wright ◽  
Bruce S. Gardiner ◽  
David W. Smith ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Kidney Injury ◽  
Renal Medulla ◽  
Detailed Knowledge ◽  
Bedside Monitoring ◽  
Quantitative Understanding ◽  
The Impact ◽  
The Relationship ◽  
Pelvic Urine ◽  
Bladder Urine

We describe the determinants of urinary oxygen tension (Po2) and the potential for use of urinary Po2 as a “physiological biomarker” of the risk of acute kidney injury (AKI) in hospital settings. We also identify knowledge gaps required for clinical translation of bedside monitoring of urinary Po2. Hypoxia in the renal medulla is a hallmark of AKI of diverse etiology. Urine in the collecting ducts would be expected to equilibrate with the tissue Po2 of the inner medulla. Accordingly, the Po2 of urine in the renal pelvis changes in response to stimuli that would be expected to alter oxygenation of the renal medulla. Oxygen exchange across the walls of the ureter and bladder will confound measurement of the Po2 of bladder urine. Nevertheless, the Po2 of bladder urine also changes in response to stimuli that would be expected to alter renal medullary oxygenation. If confounding influences can be understood, urinary bladder Po2 may provide prognostically useful information, including for prediction of AKI after cardiopulmonary bypass surgery. To translate bedside monitoring of urinary Po2 into the clinical setting, we require 1) a more detailed knowledge of the relationship between renal medullary oxygenation and the Po2 of pelvic urine under physiological and pathophysiological conditions; 2) a quantitative understanding of the impact of oxygen transport across the ureteric epithelium on urinary Po2 measured from the bladder; and 3) a simple, robust medical device that can be introduced into the bladder via a standard catheter to provide reliable and continuous measurement of urinary Po2.

scholarly journals Bladder urine oxygen tension for assessing renal medullary oxygenation in rabbits: experimental and modeling studies

2016 ◽  
Vol 311 (3) ◽  
pp. R532-R544 ◽  
Author(s):  
Ioannis Sgouralis ◽  
Michelle M. Kett ◽  
Connie P. C. Ow ◽  
Amany Abdelkader ◽  
Anita T. Layton ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Computational Model ◽  
Oxygen Tension ◽  
Oxygen Diffusion ◽  
Kidney Injury ◽  
Urine Flow ◽  
Flow Changes ◽  
Single Kidney ◽  
Pelvic Urine ◽  
Bladder Urine

Oxygen tension (Po2) of urine in the bladder could be used to monitor risk of acute kidney injury if it varies with medullary Po2. Therefore, we examined this relationship and characterized oxygen diffusion across walls of the ureter and bladder in anesthetized rabbits. A computational model was then developed to predict medullary Po2 from bladder urine Po2. Both intravenous infusion of [Phe2,Ile3,Orn8]-vasopressin and infusion of NG-nitro-l-arginine reduced urinary Po2 and medullary Po2 (8–17%), yet had opposite effects on renal blood flow and urine flow. Changes in bladder urine Po2 during these stimuli correlated strongly with changes in medullary Po2 (within-rabbit r2 = 0.87–0.90). Differences in the Po2 of saline infused into the ureter close to the kidney could be detected in the bladder, although this was diminished at lesser ureteric flow. Diffusion of oxygen across the wall of the bladder was very slow, so it was not considered in the computational model. The model predicts Po2 in the pelvic ureter (presumed to reflect medullary Po2) from known values of bladder urine Po2, urine flow, and arterial Po2. Simulations suggest that, across a physiological range of urine flow in anesthetized rabbits (0.1–0.5 ml/min for a single kidney), a change in bladder urine Po2 explains 10–50% of the change in pelvic urine/medullary Po2. Thus, it is possible to infer changes in medullary Po2 from changes in urinary Po2, so urinary Po2 may have utility as a real-time biomarker of risk of acute kidney injury.

Fundamental Issues of Environmental Education and the Impact of Socio-Economic Development on Public Health, in Globalization Context

2019 ◽  
Vol 13 (1) ◽  
pp. 29-33
Author(s):  
Străteanu Amalia-Gianina ◽  
Simona Nicoleta Stan ◽  
Laurenţiu Ciornei
Keyword(s):  
Public Health ◽  
Environmental Education ◽  
Quality Criteria ◽  
Living Environment ◽  
Detailed Knowledge ◽  
Economic Implications ◽  
Sustainable Resource Management ◽  
Skills Education ◽  
The Impact ◽  
The Relationship

Abstract Education, in general, and environmental education, in special, is salvation and future of mankind, contributing by reorientation and interdisciplinarity of education to strengthening in values, behavior and lifestyles required for sustainable future development. The ecological and economic implications of better use of information on sustainable resource management lead to the development of perspectives, knowledge and skills that are so vital to environmental education (life skills education). Unfortunately, environmental criminality has reached fourth place in the category of illicit activities at the international level. Therefore, detailed knowledge of the relationship between economic fundaments, society and the environment is strictly necessary in order to understand the values that we want to reach, the effect on performance for identifying and promoting quality criteria. These criteria help the development of a toolkit and techniques needed to increase competences and creativity, in the context of opportunities, challenges and barriers imposed by environmental security. Public health, without an adequate living environment, cannot exist and for this reason, a global effort is mandatory to raise awareness and education of the population to fight against environmental crime on our planet.

Predicting oxygen tension along the ureter

2021 ◽  
Author(s):  
Chang-Joon Lee ◽  
Bruce S. Gardiner ◽  
Roger G. Evans ◽  
David W. Smith
Keyword(s):  
Oxygen Tension ◽  
Kidney Injury ◽  
Model Parameters ◽  
Bolus Volume ◽  
Surface Area Ratio ◽  
Average Percentage ◽  
Linear Relationships ◽  
Percentage Difference ◽  
Patients At Risk ◽  
Bladder Urine

Continuous measurement of bladder urine oxygen tension (PO2) is a new method to potentially detect renal medullary hypoxia in patients at risk of acute kidney injury (AKI). To assess its practicality, we developed a computational model of the peristaltic movement of a urine bolus along the ureter and the oxygen exchange between the bolus and ureter wall. This model quantifies the changes in urine PO2 as it transits from the renal pelvis to the bladder. The model parameters were calibrated using experimental data in rabbits, such that most of the model predictions are within ± 1 standard error (SEM) of the reported mean in the experiment, with the average percentage difference being 7.0%. Based on parametric studies performed using a model scaled to the geometric dimensions of a human ureter, we found that bladder-urine PO2 is strongly dependent on the bolus volume (i.e. bolus volume-to-surface area ratio), especially at a volume less than its physiological (baseline) volume (<0.2 ml). For the model assumptions, changes in peristaltic frequency resulted in a minimal change in bladder-urine PO2 (< 1 mmHg). The model also predicted there exists a family of linear relationships of the bladder-urine PO2 and the pelvic-urine PO2 for different input conditions. We conclude that it may technically be possible to predict renal medullary PO2 based on the measurement of bladder-urine PO2, provided there are accurate real-time measurements of model input parameters.

scholarly journals Vancomycin Area Under the Curve and Acute Kidney Injury: A Meta-analysis

2019 ◽  
Vol 69 (11) ◽  
pp. 1881-1887 ◽  
Author(s):  
Doaa M Aljefri ◽  
Sean N Avedissian ◽  
Nathaniel J Rhodes ◽  
Michael J Postelnick ◽  
Kevin Nguyen ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Primary Outcome ◽  
Meta Analysis ◽  
Area Under The Curve ◽  
Kidney Injury ◽  
Monitoring Strategy ◽  
Case Control Studies ◽  
Time Curve ◽  
The Impact ◽  
The Relationship

Abstract Background This study analyzed the relationship between vancomycin area under the concentration-time curve (AUC) and acute kidney injury (AKI) reported across recent studies. Methods A systematic review of PubMed, Medline, Scopus, and compiled references was conducted. We included randomized cohort and case-control studies that reported vancomycin AUCs and risk of AKI (from 1990 to 2018). The primary outcome was AKI, defined as an increase in serum creatinine of ≥0.5 mg/L or a 50% increase from baseline on ≥2 consecutive measurements. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Primary analyses compared the impact of AUC cutpoint (greater than ~650 mg × hour/L) and AKI. Additional analysis compared AUC vs trough-guided monitoring on AKI incidence. Results Eight observational studies met inclusion/exclusion criteria with data for 2491 patients. Five studies reported first-24-hour AUCs (AUC0-24) and AKI, 2 studies reported 24- to 48-hour AUCs (AUC24-48) and AKI, and 2 studies reported AKI associated with AUC- vs trough-guided monitoring. AUC less than approximately 650 mg × hour/L was associated with decreased AKI for AUC0-24 (OR, 0.36 [95% CI, .23–.56]) as well as AUC24-48 (OR, 0.45 [95% CI, .27–.75]). AKI associated with the AUC monitoring strategy was significantly lower than trough-guided monitoring (OR, 0.68 [95% CI, .46–.99]). Conclusions AUCs measured in the first or second 24 hours and lower than approximately 650 mg × hour/L may result in a decreased risk of AKI. Vancomycin AUC monitoring strategy may result in less vancomycin-associated AKI. Additional investigations are warranted.

scholarly journals Factors that confound the prediction of renal medullary oxygenation and risk of acute kidney injury from measurement of bladder urine oxygen tension

2019 ◽  
pp. e13294 ◽  
Author(s):  
Jennifer P. Ngo ◽  
Yugeesh R. Lankadeva ◽  
Michael Z. L. Zhu ◽  
Andrew Martin ◽  
Monica Kanki ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Oxygen Tension ◽  
Kidney Injury ◽  
Bladder Urine

scholarly journals A model of oxygen transport in the rat renal medulla

2018 ◽  
Vol 315 (6) ◽  
pp. F1787-F1811 ◽  
Author(s):  
Chang-Joon Lee ◽  
Bruce S. Gardiner ◽  
Roger G. Evans ◽  
David W. Smith
Keyword(s):  
Computational Model ◽  
Oxygen Tension ◽  
Oxygen Transport ◽  
Early Stage ◽  
Kidney Injury ◽  
Gross Anatomy ◽  
Renal Medulla ◽  
Reaction Diffusion ◽  
Control Groups ◽  
Treatment Groups

The renal medulla is prone to hypoxia. Medullary hypoxia is postulated to be a leading cause of acute kidney injury, so there is considerable interest in predicting the oxygen tension in the medulla. Therefore we have developed a computational model for blood and oxygen transport within a physiologically normal rat renal medulla, using a multilevel modeling approach. For the top-level model we use the theory of porous media and advection-dispersion transport through a realistic three-dimensional representation of the medulla’s gross anatomy to describe blood flow and oxygen transport throughout the renal medulla. For the lower-level models, we employ two-dimensional reaction-diffusion models describing the distribution of oxygen through tissue surrounding the vasculature. Steady-state model predictions at the two levels are satisfied simultaneously, through iteration between the levels. The computational model was validated by simulating eight sets of experimental data regarding renal oxygenation in rats (using 4 sets of control groups and 4 sets of treatment groups, described in 4 independent publications). Predicted medullary tissue oxygen tension or microvascular oxygen tension for control groups and for treatment groups that underwent moderate perturbation in hemodynamic and renal functions is within ±2 SE values observed experimentally. Diffusive shunting between descending and ascending vasa recta is predicted to be only 3% of the oxygen delivered. The validation tests confirm that the computational model is robust and capable of capturing the behavior of renal medullary oxygenation in both normal and early-stage pathological states in the rat.

scholarly journals Haemorrhagic versus non haemorrhagic ascites in cirrhosis: Their relationship and impact on prognosis of liver cirrhosis

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Iftikhar Naqvi ◽  
Khalid Mahmood ◽  
Abu Talib
Keyword(s):  
Liver Cirrhosis ◽  
Kidney Injury ◽  
Creative Commons ◽  
Bacterial Peritonitis ◽  
Kaplan Meier ◽  
Prognosis Of Liver Cirrhosis ◽  
Group Survival ◽  
One Year ◽  
The Impact ◽  
The Relationship

Objectives: To evaluate the impact of haemorrhagic ascites on prognosis of patients with advance cirrhosis, this study was further aimed to assess the relationship between haemorrhagic ascites and advance cirrhosis and its effect on prognosis. Methods: Eight hundred and thirty-eight patients having liver cirrhosis with ascites were analyzed retrospectively (over three years) while segregated into two groups haemorrhagic and non haemorrhagic ascites. Patient outcome variables were identified among both groups and independent predictors for survival were analyzed. Kaplan-Meier survival estimates determined survival rate comparison between groups. Results: Haemorrhagic ascites was detected in (26.6%) patients. Spontaneous haemorrhagic ascites (79%) was the main cause of haemorrhagic ascites followed by hepatocellular carcinoma (14%) and iatrogenic (7.6%). Spontaneous bacterial peritonitis and acute kidney injury were statistically significant (p= 0.0001, 0.0001) among groups. Overall mortality at year three was higher (83%) in haemorrhagic ascites group. Survival among both groups (haemorrhagic versus non haemorrhagic) at one month, one year and three year was found to be significant (p= 0.000, 0.000 and 0.000). Conclusion: Haemorrhagic ascites impact overall survival with more mortality in comparison to non haemorrhagic ascites. Haemorrhagic ascites was an independent predictor of survival. Haemorrhagic ascites is possibly considered another predictor of survival among advance cirrhosis. doi: https://doi.org/10.12669/pjms.36.4.2075 How to cite this:Naqvi IH, Mahmood K, Talib A. Haemorrhagic versus non haemorrhagic ascites in cirrhosis: Their relationship and impact on prognosis of liver cirrhosis. Pak J Med Sci. 2020;36(4):---------. doi: https://doi.org/10.12669/pjms.36.4.2075 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

Business: Making Cents of Coding Systems: Billing for Professional Services

2010 ◽  
Vol 20 (1) ◽  
pp. 3-8
Author(s):  
Dee Adams Nikjeh
Keyword(s):  
Professional Services ◽  
Speech Language Pathology ◽  
Coding Systems ◽  
Language Pathology ◽  
Program Funding ◽  
Fee Schedule ◽  
Procedure Codes ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

Abstract Administrators and supervisors face daily challenges over issues such as program funding, service fees, correct coding procedures, and the ever-changing healthcare regulations. Receiving equitable reimbursement for speech-language pathology and audiology services necessitates an understanding of federal coding and reimbursement systems. This tutorial provides information pertaining to two major healthcare coding systems and explains the relationship of these systems to clinical documentation, the Medicare Physician Fee Schedule and equitable reimbursement. An explanation of coding edits and coding modifiers is provided for use in those occasional atypical situations when the standard use of procedural coding may not be appropriate. Also included in this tutorial is a brief discussion of the impact that the Medicare Improvements for Patients and Providers Act of 2008 (HR 6331 Medicare Improvements for Patients and Providers Act [MIPPA], 2008) has had on the valuation of speech-language pathology procedure codes.

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