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Wang JY, Song QL, Wang YL, Jiang ZM. Urinary oxygen tension and its role in predicting acute kidney injury: A narrative review. J Clin Anesth 2024; 93:111359. [PMID: 38061226 DOI: 10.1016/j.jclinane.2023.111359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 11/12/2023] [Accepted: 12/01/2023] [Indexed: 01/14/2024]
Abstract
Acute kidney injury occurs frequently in the perioperative setting. The renal medulla often endures hypoxia or hypoperfusion and is susceptible to the imbalance between oxygen supply and demand due to the nature of renal blood flow distribution and metabolic rate in the kidney. The current available evidence demonstrated that the urine oxygen pressure is proportional to the variations of renal medullary tissue oxygen pressure. Thus, urine oxygenation can be a candidate for reflecting the change of oxygen in the renal medulla. In this review, we discuss the basic physiology of acute kidney injury, as well as techniques for monitoring urine oxygen tension, confounding factors affecting the reliable measurement of urine oxygen tension, and its clinical use, highlighting its potential role in early detection and prevention of acute kidney injury.
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Affiliation(s)
- Jing-Yan Wang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Qi-Liang Song
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Yu-Long Wang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Zong-Ming Jiang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China.
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2
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Kato T, Shiko Y, Koyama K. Urine collection using a 3-way urethral catheter for PuO 2. J Anesth 2024; 38:284-285. [PMID: 37904041 PMCID: PMC10955010 DOI: 10.1007/s00540-023-03276-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 10/12/2023] [Indexed: 11/01/2023]
Affiliation(s)
- Takao Kato
- Department of Anesthesiology, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan.
| | - Yuki Shiko
- Department of Anesthesiology, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
- Biostatistics Section, Clinical Research Center, Chiba University Hospital, Chiba, Japan
| | - Kaoru Koyama
- Department of Anesthesiology, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
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Lofgren LR, Silverton NA, Kuck K, Hall IE. The impact of urine flow on urine oxygen partial pressure monitoring during cardiac surgery. J Clin Monit Comput 2023; 37:21-27. [PMID: 35648329 DOI: 10.1007/s10877-022-00843-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/06/2022] [Indexed: 01/24/2023]
Abstract
PURPOSE Urine oxygen partial pressure (PuO2) may be useful for assessing acute kidney injury (AKI) risk. The primary purpose of this study was to quantify the ability of a novel urinary oxygen monitoring system to make real-time PuO2 measurements intraoperatively which depends on adequate urine flow. We hypothesized that PuO2 data could be acquired with enough temporal resolution to provide real-time information in both AKI and non-AKI patients. METHODS PuO2 and urine flow were analyzed in 86 cardiac surgery patients. PuO2 data associated with low (< 0.5 ml/kg/hr) or retrograde urine flow were discarded. Patients were excluded if > 70% of their data were discarded during the respective periods, i.e., during cardiopulmonary bypass (CPB), before CPB (pre-CPB), and after CPB (post-CPB). The length of intervals of discarded data were recorded for each patient. The median length of intervals of discarded data were compared between AKI and non-AKI patients and between surgical periods. RESULTS There were more valid PuO2 data in CPB and post-CPB periods compared to the pre-CPB period (81% and 90% vs. 31% of patients included, respectively; p < 0.001 and p < 0.001). Most intervals of discarded data were < 3 minutes during CPB (96%) and post-CPB (98%). The median length was < 25 s during all periods and there was no significant difference in the group median length of discarded data intervals for AKI and non-AKI patients. CONCLUSIONS PuO2 measurements were acquired with enough temporal resolution to demonstrate real-time PuO2 monitoring during CPB and the post-CPB period. CLINICALTRIALS GOV IDENTIFIER NCT03335865, First Posted Date: Nov. 8th, 2017.
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Affiliation(s)
- Lars R Lofgren
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA. .,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
| | | | - Kai Kuck
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Isaac E Hall
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah, Salt Lake City, UT, USA
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4
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Hu RT, Lankadeva YR, Yanase F, Osawa EA, Evans RG, Bellomo R. Continuous bladder urinary oxygen tension as a new tool to monitor medullary oxygenation in the critically ill. Crit Care 2022; 26:389. [PMID: 36527088 PMCID: PMC9758873 DOI: 10.1186/s13054-022-04230-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/09/2022] [Indexed: 12/23/2022] Open
Abstract
Acute kidney injury (AKI) is common in the critically ill. Inadequate renal medullary tissue oxygenation has been linked to its pathogenesis. Moreover, renal medullary tissue hypoxia can be detected before biochemical evidence of AKI in large mammalian models of critical illness. This justifies medullary hypoxia as a pathophysiological biomarker for early detection of impending AKI, thereby providing an opportunity to avert its evolution. Evidence from both animal and human studies supports the view that non-invasively measured bladder urinary oxygen tension (PuO2) can provide a reliable estimate of renal medullary tissue oxygen tension (tPO2), which can only be measured invasively. Furthermore, therapies that modify medullary tPO2 produce corresponding changes in bladder PuO2. Clinical studies have shown that bladder PuO2 correlates with cardiac output, and that it increases in response to elevated cardiopulmonary bypass (CPB) flow and mean arterial pressure. Clinical observational studies in patients undergoing cardiac surgery involving CPB have shown that bladder PuO2 has prognostic value for subsequent AKI. Thus, continuous bladder PuO2 holds promise as a new clinical tool for monitoring the adequacy of renal medullary oxygenation, with its implications for the recognition and prevention of medullary hypoxia and thus AKI.
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Affiliation(s)
- Raymond T. Hu
- grid.410678.c0000 0000 9374 3516Department of Anaesthesia, Austin Health, Heidelberg, VIC Australia ,grid.1008.90000 0001 2179 088XDepartment of Critical Care, Melbourne Medical School, The University of Melbourne, Parkville, VIC Australia
| | - Yugeesh R. Lankadeva
- grid.1008.90000 0001 2179 088XDepartment of Critical Care, Melbourne Medical School, The University of Melbourne, Parkville, VIC Australia ,grid.1008.90000 0001 2179 088XPre-Clinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC Australia
| | - Fumitake Yanase
- grid.414094.c0000 0001 0162 7225Department of Intensive Care, Austin Hospital, Heidelberg, Australia
| | - Eduardo A. Osawa
- Cardiology Intensive Care Unit, DF Star Hospital, Brasília, Brazil ,grid.472984.4D’Or Institute for Research and Education (IDOR), DF Star Hospital, Brasília, Brazil
| | - Roger G. Evans
- grid.1008.90000 0001 2179 088XPre-Clinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC Australia ,grid.1002.30000 0004 1936 7857Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC Australia
| | - Rinaldo Bellomo
- grid.1008.90000 0001 2179 088XDepartment of Critical Care, Melbourne Medical School, The University of Melbourne, Parkville, VIC Australia ,grid.414094.c0000 0001 0162 7225Department of Intensive Care, Austin Hospital, Heidelberg, Australia ,grid.1002.30000 0004 1936 7857Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Australia ,grid.416153.40000 0004 0624 1200Department of Intensive Care, Royal Melbourne Hospital, Parkville, Australia
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5
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Hu R, Yanase F, McCall P, Evans R, Raman J, Bellomo R. The effects of targeted changes in systemic blood flow and mean arterial pressure on urine oximetry during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2022; 36:3551-3560. [DOI: 10.1053/j.jvca.2022.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 11/11/2022]
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6
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Lee CJ, Gardiner BS, Evans RG, Smith DW. Predicting oxygen tension along the ureter. Am J Physiol Renal Physiol 2021; 321:F527-F547. [PMID: 34459223 DOI: 10.1152/ajprenal.00122.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Continuous measurement of bladder urine oxygen tension (Po2) is a 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 urine 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 SE of the reported mean in the experiment, with the average percent difference being 7.0%. Based on parametric experiments 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 that there exists a family of linear relationships between the bladder-urine Po2 and 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 that there are accurate real-time measurements of model input parameters.NEW & NOTEWORTHY Measurement of bladder urine oxygen tension has been proposed as a new method to potentially detect the risk of acute kidney injury in patients. A computational model of oxygen exchange between urine bolus and ureteral tissue shows that it may be technically possible to determine the risk of acute kidney injury based on the measurement of bladder urine oxygen tension, provided that the measurement data are properly interpreted via a computational model.
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Affiliation(s)
- Chang-Joon Lee
- College of Science, Health, Engineering and Education, Murdoch University, Perth, Western Australia, Australia.,Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Bruce S Gardiner
- College of Science, Health, Engineering and Education, Murdoch University, Perth, Western Australia, Australia.,Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Roger G Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - David W Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
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7
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Noninvasive Urine Oxygen Monitoring and the Risk of Acute Kidney Injury in Cardiac Surgery. Anesthesiology 2021; 135:406-418. [PMID: 34329393 DOI: 10.1097/aln.0000000000003663] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Acute kidney injury (AKI) is a common complication of cardiac surgery. An intraoperative monitor of kidney perfusion is needed to identify patients at risk for AKI. The authors created a noninvasive urinary oximeter that provides continuous measurements of urinary oxygen partial pressure and instantaneous urine flow. They hypothesized that intraoperative urinary oxygen partial pressure measurements are feasible with this prototype device and that low urinary oxygen partial pressure during cardiac surgery is associated with the subsequent development of AKI. METHODS This was a prospective observational pilot study. Continuous urinary oxygen partial pressure and instantaneous urine flow were measured in 91 patients undergoing cardiac surgery using a novel device placed between the urinary catheter and collecting bag. Data were collected throughout the surgery and for 24 h postoperatively. Clinicians were blinded to the intraoperative urinary oxygen partial pressure and instantaneous flow data. Patients were then followed postoperatively, and the incidence of AKI was compared to urinary oxygen partial pressure measurements. RESULTS Intraoperative urinary oxygen partial pressure measurements were feasible in 86/91 (95%) of patients. When urinary oxygen partial pressure data were filtered for valid urine flows greater than 0.5 ml · kg-1 · h-1, then 70/86 (81%) and 77/86 (90%) of patients in the cardiopulmonary bypass (CPB) and post-CPB periods, respectively, were included in the analysis. Mean urinary oxygen partial pressure in the post-CPB period was significantly lower in patients who subsequently developed AKI than in those who did not (mean difference, 6 mmHg; 95% CI, 0 to 11; P = 0.038). In a multivariable analysis, mean urinary oxygen partial pressure during the post-CPB period remained an independent risk factor for AKI (relative risk, 0.82; 95% CI, 0.71 to 0.95; P = 0.009 for every 10-mmHg increase in mean urinary oxygen partial pressure). CONCLUSIONS Low urinary oxygen partial pressures after CPB may be associated with the subsequent development of AKI after cardiac surgery. EDITOR’S PERSPECTIVE
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8
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Stafford-Smith M. Could Trended Oxygen Partial Pressure in the Urine Be the "ST Segment" Kidney Monitor We've Been Looking For? Anesthesiology 2021; 135:380-381. [PMID: 34329391 DOI: 10.1097/aln.0000000000003869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Ullah MM, Basile DP. Role of Renal Hypoxia in the Progression From Acute Kidney Injury to Chronic Kidney Disease. Semin Nephrol 2020; 39:567-580. [PMID: 31836039 DOI: 10.1016/j.semnephrol.2019.10.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Over the past 20 years, there has been an increased appreciation of the long-term sequelae of acute kidney injury (AKI) and the potential development of chronic kidney disease (CKD). Several pathophysiologic features have been proposed to mediate AKI to CKD progression including maladaptive alterations in tubular, interstitial, inflammatory, and vascular cells. These alterations likely interact to culminate in the progression to CKD. In this article we focus primarily on evidence of vascular rarefaction secondary to AKI, and the potential mechanisms by which rarefaction occurs in relation to other alterations in tubular and interstitial compartments. We further focus on the potential that rarefaction contributes to renal hypoxia. Consideration of the role of hypoxia in AKI to CKD transition focuses on experimental evidence of persistent renal hypoxia after AKI and experimental maneuvers to evaluate the influence of hypoxia, per se, in progressive disease. Finally, consideration of methods to evaluate hypoxia in patients is provided with the suggestion that noninvasive measurement of renal hypoxia may provide insight into progression in post-AKI patients.
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Affiliation(s)
- Md Mahbub Ullah
- Department of Anatomy, Cell Biology and Physiology, Indiana University, Indianapolis, IN
| | - David P Basile
- Department of Medicine, Division of Nephrology, Indiana University, Indianapolis, IN.
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10
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Zhu MZL, Martin A, Cochrane AD, Smith JA, Thrift AG, Harrop GK, Ngo JP, Evans RG. Urinary hypoxia: an intraoperative marker of risk of cardiac surgery-associated acute kidney injury. Nephrol Dial Transplant 2018; 33:2191-2201. [DOI: 10.1093/ndt/gfy047] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 02/06/2018] [Indexed: 01/06/2023] Open
Affiliation(s)
- Michael Z L Zhu
- Department of Cardiothoracic Surgery, Monash Health and Department of Surgery (School of Clinical Sciences at Monash Health), Monash University, Clayton, Australia
| | - Andrew Martin
- Department of Cardiothoracic Surgery, Monash Health and Department of Surgery (School of Clinical Sciences at Monash Health), Monash University, Clayton, Australia
| | - Andrew D Cochrane
- Department of Cardiothoracic Surgery, Monash Health and Department of Surgery (School of Clinical Sciences at Monash Health), Monash University, Clayton, Australia
| | - Julian A Smith
- Department of Cardiothoracic Surgery, Monash Health and Department of Surgery (School of Clinical Sciences at Monash Health), Monash University, Clayton, Australia
| | - Amanda G Thrift
- Department of Medicine (School of Clinical Sciences at Monash Health), Monash University, Melbourne, Australia and
| | - Gerard K Harrop
- Department of Cardiothoracic Surgery, Monash Health and Department of Surgery (School of Clinical Sciences at Monash Health), Monash University, Clayton, Australia
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Jennifer P Ngo
- Department of Cardiothoracic Surgery, Monash Health and Department of Surgery (School of Clinical Sciences at Monash Health), Monash University, Clayton, Australia
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Roger G Evans
- Department of Cardiothoracic Surgery, Monash Health and Department of Surgery (School of Clinical Sciences at Monash Health), Monash University, Clayton, Australia
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
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11
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Sgouralis I, Kett MM, Ow CPC, Abdelkader A, Layton AT, Gardiner BS, Smith DW, Lankadeva YR, Evans RG. Bladder urine oxygen tension for assessing renal medullary oxygenation in rabbits: experimental and modeling studies. Am J Physiol Regul Integr Comp Physiol 2016; 311:R532-44. [PMID: 27385734 DOI: 10.1152/ajpregu.00195.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/02/2016] [Indexed: 11/22/2022]
Abstract
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 [Phe(2),Ile(3),Orn(8)]-vasopressin and infusion of N(G)-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 r(2) = 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.
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Affiliation(s)
- Ioannis Sgouralis
- National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, Tennessee
| | - Michelle M Kett
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Connie P C Ow
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Amany Abdelkader
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Anita T Layton
- Department of Mathematics, Duke University, Durham, North Carolina
| | - Bruce S Gardiner
- School of Engineering and Information Technology, Murdoch University, Perth, Western Australia
| | - David W Smith
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, Western Australia; and
| | - Yugeesh R Lankadeva
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Roger G Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia;
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12
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Stafford-Smith M, Grocott HP. Renal medullary hypoxia during experimental cardiopulmonary bypass: a pilot study. Perfusion 2016; 20:53-8. [PMID: 15751671 DOI: 10.1191/0267659105pf780oa] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Objectives: To determine the effect of cardiopulmonary bypass (CPB) on renal medullary oxygenation. Design: Observational. Setting: Laboratory. Participants: Pigs ( n=3). Interventions: Following induction of general anesthesia, a Paratrend™ blood gas probe was placed directly into the left renal medulla. Two animals were subjected to 90 min of CPB, while a third served as a non-CPB control. A probe was also placed in the left renal pelvis of one (CPB) animal to allow direct urine PO2measurements. Measurements and main results: Medullary hypoxia (PO2B < 65 mmHg) was evident prior to CPB. With the onset of CPB, medullary PO2 further declined to nearly unmeasurable levels; PCO2 and pH were unchanged. Brief circulatory arrest during CPB in one animal resulted in rapid additional PCO2 rise and pH decline that corrected with reperfusion. Following the cessation of CPB, medullary PO2 gradually increased, but remained lower than pre-CPB levels. No changes in medullary PO2 were observed in the sham animal. Renal pelvis urine PO2, but not pH or PCO2, appeared to correlate with medullary values at all times. Conclusions: Our findings indicate that renal medullary hypoxia is extreme during CPB and may persist following CPB. These data suggest a basis for the vulnerability of the kidney to injury during cardiac surgery. Renal pelvis urine PO2 appears to correlate closely with medullary PO2 and may be a useful tool for studying medullary oxygenation during CPB in humans.
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Affiliation(s)
- Mark Stafford-Smith
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA.
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13
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Effect of iodinated contrast medium in diabetic rat kidneys as evaluated by blood-oxygenation-level-dependent magnetic resonance imaging and urinary neutrophil gelatinase-associated lipocalin. Invest Radiol 2016; 50:392-6. [PMID: 25668748 DOI: 10.1097/rli.0000000000000141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVES The objective of this study was to assess whether streptozotocin (STZ)-induced diabetic rats develop iodinated contrast-induced acute kidney injury. The intrarenal R2* (=1/T2*) was evaluated continuously before, during, and after contrast administration. Renal injury was confirmed using urinary neutrophil gelatinase-associated lipocalin measurements. MATERIALS AND METHODS Six Sprague-Dawley rats were administered with STZ to induce diabetes (group 1). R2* was measured before, during, and after administration of iodixanol. R2* readings were sampled from 4 renal regions: inner medulla, inner stripe of outer medulla (ISOM), outer stripe of outer medulla, and cortex. Peak R2* and initial upslope of R2* increase after iodinated contrast were calculated. Data from 12 nondiabetic rats pretreated with nitric oxide synthase and prostaglandin inhibitors to induce susceptibility to contrast-induced acute kidney injury (pretreatment model) from a previous study were reanalyzed for peak R2* and initial upslope of R2* increase after contrast. Six of these animals received saline (group 2), and the other 6 received furosemide (group 3) before iodixanol. RESULTS Peak R2* and initial upslope of R2* increase were used as blood-oxygenation-level-dependent response parameters. R2* in ISOM was comparable in all 3 groups before administration of furosemide/saline. Except for the furosemide group, ISOM showed a rapid increase in R2* immediately after contrast administration. Unlike the L-NAME- and indomethacin-treated groups, the diabetic group showed a quick reversal of R2* toward baseline measurements after contrast administration. Urinary neutrophil gelatinase-associated lipocalin indicated significant increase in diabetic rats 4 hours after contrast administration. The observed trends with peak R2* and initial upslope of R2* increase in renal ISOM were in agreement with those of urinary neutrophil gelatinase-associated lipocalin. CONCLUSIONS The STZ-induced diabetic rat may be suitable for studying the effects of iodinated contrast on renal oxygenation status and may mimic human condition closer than the pretreatment model described before. The peak R2* value and initial upslope of R2* in ISOM appear to be effective magnetic resonance imaging markers to predict renal injury after administration of an iodinated contrast agent.
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14
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Evans RG, Smith JA, Wright C, Gardiner BS, Smith DW, Cochrane AD. Urinary oxygen tension: a clinical window on the health of the renal medulla? Am J Physiol Regul Integr Comp Physiol 2014; 306:R45-50. [DOI: 10.1152/ajpregu.00437.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
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.
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Affiliation(s)
| | | | - Christopher Wright
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Bruce S. Gardiner
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, Australia
| | - David W. Smith
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, Australia
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15
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Karhausen J, Stafford-Smith M. The role of nonocclusive sources of acute gut injury in cardiac surgery. J Cardiothorac Vasc Anesth 2013; 28:379-91. [PMID: 24119676 DOI: 10.1053/j.jvca.2013.04.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Indexed: 12/16/2022]
Affiliation(s)
- Jörn Karhausen
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina.
| | - Mark Stafford-Smith
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
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16
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Wang ZJ, Joe BN, Coakley FV, Zaharchuk G, Busse R, Yeh BM. Urinary oxygen tension measurement in humans using magnetic resonance imaging. Acad Radiol 2008; 15:1467-73. [PMID: 18995198 DOI: 10.1016/j.acra.2008.04.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Revised: 04/06/2008] [Accepted: 04/09/2008] [Indexed: 11/25/2022]
Abstract
RATIONALE AND OBJECTIVES Renal medullary hypoxia is frequently implicated in renal dysfunction, and urinary oxygen tension (PO(2)) in the renal pelvis can be used as a surrogate for the adjacent renal medullary oxygenation. We sought to assess the feasibility of magnetic resonance (MR) quantification of urinary PO(2) in humans. MATERIALS AND METHODS The longitudinal relaxivity (R1) of fluids is linearly related to PO(2), allowing MR quantification of urinary PO(2). We imaged urine phantoms with a range of PO(2) using a real-time saturation recovery T2-prepped single-shot fast spin-echo sequence to calibrate urine R1 values to PO(2). Following institutional review board approval, we imaged the urinary bladders of seven healthy subjects while they were breathing room air and the renal pelvis of nine healthy subjects while they were breathing room air or 100% oxygen via facemask. The renal pelvic urine PO(2) was compared before, during, and after 100% oxygen breathing. RESULTS Our phantom study confirmed that urine R1 is linearly related to PO(2): PO(2) (mm Hg) = (R1 - 0.2253 s(-1))/(2.61e(-4) s(-1)/mm Hg). The mean bladder urine PO(2) ranged from 23 to 45 mm Hg among the seven subjects. Successful MR measurements of renal pelvic urine PO(2) were obtained in seven of nine healthy subjects. Following 100% O(2) breathing, the renal pelvic urine PO(2) showed a significant mean increase of 29 mm Hg (P < .05). CONCLUSIONS We show that MR quantification of urinary PO(2) is feasible. Noninvasive renal pelvic urine PO(2) determinations could serve as a valuable indirect measure for renal medullary oxygenation, allowing for clinical investigations of the role of renal medullary hypoxia in renal disease.
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Valente A, Sorrentino L, La Torre G, Draisci G. POST-TRANSFUSIONAL VARIATION IN URINARY OXYGEN TENSION IN SURGICAL PATIENTS. Clin Exp Pharmacol Physiol 2008; 35:1109-12. [DOI: 10.1111/j.1440-1681.2008.04949.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Morelli A, Rocco M, Conti G, Orecchioni A, Alberto De Blasi R, Coluzzi F, Pietropaoli P. Monitoring Renal Oxygen Supply in Critically-Ill Patients Using Urinary Oxygen Tension. Anesth Analg 2003; 97:1764-1768. [PMID: 14633556 DOI: 10.1213/01.ane.0000087037.41342.4f] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED Critically-ill patients are at risk of developing renal disorders as a consequence of systemic hypoperfusion. Ischemic acute tubular necrosis and resulting acute renal failure are caused by hypotension or therapeutic management. In this study, we tested the change of O(2) availability induced by fenoldopam mesylate using the continuous measurement of urinary oxygen tension (PuO(2)), a relatively noninvasive technique that could provide potentially important real-time data regarding renal oxygenation in intensive care unit patients. Fenoldopam was administered at different doses (0.03, 0.06, and 0.09 microg x kg(-1) x min(-1)) to 50 stable critically-ill patients. Urine output was collected every hour to assess volume and urinary electrolytes. Heart rate, mean arterial blood pressure, cardiac output, pulmonary artery occlusion pressure, arterial oxygen delivery index, and oxygen consumption index were analyzed after fenoldopam dose modifications and at infusion end. PaO(2) and PuO(2) continuous measurements were obtained through two sensors inserted in the radial artery and in the bladder. After a fenoldopam dose increase, PuO(2) significantly increased (P < 0.05), whereas PaO(2) remained unchanged. During the study, heart rate, mean arterial blood pressure, cardiac output, central venous pressure, pulmonary artery occlusion pressure, arterial oxygen delivery index, and oxygen consumption remained unchanged. Dose-dependent PuO(2) increases, unrelated to indexes of systemic perfusion and cardiac function, demonstrate that fenoldopam affects the balance between renal oxygen supply and demand in stable critically-ill patients. IMPLICATIONS Acute renal failure in critically-ill patients is associated with frequent mortality. Prolonged renal hypoperfusion cannot be detected by current systemic hemodynamic indexes. Using continuous measurement of urinary oxygen tension, which could indirectly provide real-time data regarding renal oxygenation, our study showed that fenoldopam increases the ratio between oxygen supply and demand.
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Affiliation(s)
- Andrea Morelli
- *Department of Anesthesiology and Intensive Care, University of Rome "La Sapienza"; and †Department of Anesthesiology and Intensive Care, Catholic University of Rome, Italy
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Kainuma M, Yamada M, Miyake T. Continuous urine oxygen tension monitoring in patients undergoing cardiac surgery. J Cardiothorac Vasc Anesth 1996; 10:603-8. [PMID: 8841867 DOI: 10.1016/s1053-0770(96)80137-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To evaluate the effect of cardiopulmonary bypass (CPB) on urine oxygen tension (PuO2) and to determine whether perioperative PuO2 can predict postoperative renal dysfunction in patients undergoing cardiac surgery. DESIGN Prospective clinical study. SETTING A university research laboratory, a university-affiliated hospital. PARTICIPANTS Ninety-eight consecutive adult patients undergoing coronary artery bypass surgery or valvular surgery. INTERVENTIONS PuO2 was continuously measured by inserting a polarographic electrode into the urinary tube connected to a Foley catheter. MEASUREMENTS AND MAIN RESULTS PuO2 was constant before CPB and then progressively decreased after the start of CPB. It partially recovered at weaning from CPB but did not completely return to its original level until the end of surgery. Postoperative serum creatinine concentrations were significantly higher in patients whose PuO2 decreased after CPB, as compared with those whose PuO2 was constant or increased. The amplitude and the rate of recovery in PuO2 after CPB were significantly associated with peak values of postoperative serum creatinine concentrations. CONCLUSIONS These results suggest the possibility of PuO2 detecting an early stage of renal dysfunction in cardiac surgery, although further studies will be required to substantiate it.
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Affiliation(s)
- M Kainuma
- Department of Anesthesiology, Fujita Health University School of Medicine, Aichi, Japan
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Wong DH, Weir PD, Wesley RC, Gordon IL, Weber EC, Zaccari J, Ferraro LM, Tremper KK. Changes in renal vein, renal surface, and urine oxygen tension during hypoxia in pigs. J Clin Monit Comput 1993; 9:1-4. [PMID: 8463800 DOI: 10.1007/bf01627629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To determine whether ureteral urine oxygen tension could serve as a monitor of renal hypoxia and its relationship to other renal O2 tension parameters, we simultaneously measured femoral artery (PaO2), renal vein (PrvO2), renal surface (PrsO2), and ureteral urine (PuO2) oxygen tensions in 8 anesthetized pigs while incrementally decreasing the inspired oxygen concentration (FiO2) from 21% to 12%. Renal artery blood flow, measured by transit time ultrasound, renal oxygen consumption, and thermodilution cardiac output, was constant. Changes in PaO2, PrvO2, PrsO2, and PuO2 caused by decreasing FiO2 were evaluated by one-way analysis of variance. The relationships between PuO2 and the other O2 tension parameters were evaluated by correlation coefficient and linear regression statistics. Of six possible O2 decrements (combinations of 3, 6, and 9%), only PrvO2 significantly decreased with all six decrements. PuO2 decreased when FiO2 decreased 6% or more. PuO2 is not a sensitive indicator of systemic hypoxia. Under constant renal perfusion and oxygen consumption, PuO2 had a correlation coefficient of 0.80 and a regression equation of PuO2 = 0.84 (PrvO2) + 11.6, with PrvO2. PuO2 is related to PrvO2 when renal perfusion is constant.
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Affiliation(s)
- D H Wong
- Department of Anesthesiology, Long Beach Veterans Administration Medical Center, CA 90822
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Behnia R, Martin A, Koushanpour E, Brunner EA. Trimethaphan-induced hypotension: effect on renal function. CANADIAN ANAESTHETISTS' SOCIETY JOURNAL 1982; 29:581-6. [PMID: 7139398 DOI: 10.1007/bf03007745] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
This study was designed to evaluate the effects of trimethaphan-induced hypotension on renal function in healthy young patients undergoing maxillofacial surgery. Anaesthesia was induced with thiopentone and was maintained with halothane 1.5-2.0 per cent in oxygen. Each patient served as his own control, and data were analyzed using the paired t-test. Trimethaphan was infused at a rate of 45-52 microgram.kg-1.min-1 for an average hypotensive period of 53 +/- 4 (mean +/- SEM) minutes to reduce the mean arterial pressure (MAP) to 49 +/- 2 torr. Endogenous creatinine clearance, urinary Po2, sodium reabsorption rate (Tna), and serum and urine osmolalities were determined before, during and after arterial hypotension with trimethaphan. Urine flow averaged 2.9 +/- 1 ml/min during the period of hypotension. Endogenous creatinine clearance and Tna were significantly decreased (p less than 0.05) in the hypotensive period. These values returned to normal levels within one hour upon discontinuation of trimethaphan and restoration of blood pressure. We found no statistical difference in urine Po2, and serum and urine osmolalities during control, hypotensive and recovery periods. These results suggest that medullary renal tissue oxygenation, an index of tissue viability, may have remained adequate despite a significant reduction in endogenous creatinine clearance during the hypotensive period. Furthermore, it appears that the effect of trimethaphan-induced hypotension on renal function is similar to the sodium nitroprusside-induced hypotension in man which we have reported previously.
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