1
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Jonsson P, Stegmayr C, Stegmayr B, Forsberg U. Venous chambers in clinical use for hemodialysis have limited capacity to eliminate microbubbles from entering the return bloodline: An in vitro study. Artif Organs 2023. [PMID: 36594759 DOI: 10.1111/aor.14495] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/24/2022] [Accepted: 12/27/2022] [Indexed: 01/04/2023]
Abstract
BACKGROUND During hemodialysis (HD), blood passes through an extracorporeal circuit (ECC). To prevent air administration to the patient, a venous chamber (chamber) is located before the blood return. Microbubbles (MBs) may pass through the chamber and end up as microemboli in organs such as the brain and heart. This in vitro study investigated the efficacy of various chambers in MB removal. MATERIALS AND METHODS The in vitro recirculated setting of an ECC included an FX10 dialyzer, a dextran-albumin solution to mimic blood viscosity and chambers with different flow characteristics in clinical use (Baxter: AK98 and Artis, Fresenius: 5008 and 6008) and preclinical test (Embody: Emboless®). A Gampt BCC200 device measured the presence and size of MBs (20-500 μm). Percentage change of MBs was calculated: ΔMB% = 100*(outlet-inlet)/inlet for each size of MB. Blood pump speed (Qb) was 200 (Qb200) or 300 (Qb300) ml/minute. Wilcoxon paired test determined differences. RESULTS With Qb200 median ΔMB% reduction was: Emboless -58%, AK98 -24%, Fresenius 5008 -23%, Artis -8%, and Fresenius 6008 ± 0%. With Qb300 ΔMB% was: Emboless -36%, AK98 ± 0%, Fresenius 5008 ± 0%, Artis +25%, and Fresenius 6008 + 21%. The Emboless was superior to all other chambers with Qb200 and Qb300 (p < 0.001). Further, the Emboless with Qb300 still eliminated more MBs than all other chambers with Qb200 (p ≤ 0.003). CONCLUSION The results from the present study indicate that flow characteristics of the chamber and the Qb are important factors to limiting exposure of MB to the return bloodline. The Emboless chamber reduced MBs more effective than those chambers in clinical use investigated.
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Affiliation(s)
- Per Jonsson
- Department of Public Health and Clinical Medicine, Umea University, Umea, Sweden
| | - Christofer Stegmayr
- Department of Public Health and Clinical Medicine, Umea University, Umea, Sweden
| | - Bernd Stegmayr
- Department of Public Health and Clinical Medicine, Umea University, Umea, Sweden
| | - Ulf Forsberg
- Department of Public Health and Clinical Medicine, Umea University, Umea, Sweden
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2
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Forsberg U, Jonsson P, Stegmayr B. Microemboli induced by air bubbles may be deposited in organs as a consequence of contamination during medical care. Clin Kidney J 2022; 16:159-166. [PMID: 36726427 PMCID: PMC9871849 DOI: 10.1093/ckj/sfac217] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Background Larger volumes of accidental air infused during medical care may end up as emboli while microbubbles of air are supposed to be absorbed and cause no harm. The aim of this autopsy study was to investigate if microbubbles of air accidently entering the bloodline may be detected as microemboli (ME) in tissue such as lungs, brain and heart. If so, do differences in prevalence exist between haemodialysis (HD) and amyotrophic lateral sclerosis (ALS) patients. Methods Included were data from 44 patients treated by medical healthcare before death. Twenty-five cases had been treated with chronic HD and 19 cases died from ALS. Since air in the bloodline activates coagulation, ME could appear. To discriminate between microbubbles caused by artificial contamination during autopsy versus microbubbles deposited in vivo, tissues were stained with a polyclonal fluorescent antibody against fibrinogen, fibrin and fragments E and D. Fluorescence staining was used to visualize ME counted within 25 microscopic fields (600×) of a tissue preparation. One tissue preparation was used if available from the lung, heart and frontal lobe of the brain and in five cases also the cerebellum. Results Microbubbles can be verified at autopsy as ME in the lung, heart and brain in tissue from patients exposed to more extensive medical care. There were significantly more ME in the lungs versus the heart or brain. Women had fewer ME than men. The HD group had a higher median of ME per section than the ALS group (lung: 6 versus 3, P = .007; heart: 2.5 versus 1, P = .013; brain: 7.5 versus 2, P = .001) and had more sections with ME findings than the ALS group (P = .002). A correlation existed between the time on HD (months) and ME in the lungs. Conclusions More ME were present in HD patients compared with those who suffered from ALS. Minimizing air contamination from syringes, infusions and bloodlines will decrease ME and subsequent tissue injury.
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Affiliation(s)
| | - Per Jonsson
- Unit of Medicine, Umeå University, Umeå, Sweden
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3
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Shiroud Heidari B, Bappoo N, Kelsey LJ, Davachi SM, Doyle B. Multi‐response optimization of shrinkage, clamp force, and part weight in simulated injection molding process of a dialysis micro‐filter. J Appl Polym Sci 2022. [DOI: 10.1002/app.51732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Behzad Shiroud Heidari
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research The University of Western Australia Perth Australia
- School of Engineering The University of Western Australia Perth Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies The University of Melbourne Parkville Victoria Australia
| | - Nikhilesh Bappoo
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research The University of Western Australia Perth Australia
- School of Engineering The University of Western Australia Perth Australia
| | - Lachlan J. Kelsey
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research The University of Western Australia Perth Australia
- School of Engineering The University of Western Australia Perth Australia
| | - Seyed Mohammad Davachi
- Department of Biological and Chemistry Texas A&M International University Laredo Texas USA
- Department of Food Science, College of Agriculture and Life Sciences Cornell University Ithaca New York USA
| | - Barry Doyle
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research The University of Western Australia Perth Australia
- School of Engineering The University of Western Australia Perth Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies The University of Melbourne Parkville Victoria Australia
- British Heart Foundation Centre for Cardiovascular Science The University of Edinburgh Edinburgh UK
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4
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Raina R, Sethi S, Khooblall A, Kher V, Deshpande S, Yerigeri K, Pandya A, Nair N, Datla N, McCulloch M, Bunchman T, Davenport A. Non-anticoagulation pediatric continuous renal replacement therapy methods to increase circuit life. Hemodial Int 2022; 26:147-159. [PMID: 34989465 DOI: 10.1111/hdi.13003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Acute kidney injury (AKI) is a clinical condition characterized by an abrupt increase in serum creatinine levels due to functional changes in the kidneys from a newfound insult or injury. For supportive treatment, continuous renal replacement therapy (CRRT) is one of the most widely used modalities due to its precise control of fluid balance over extended periods of time. However, its complications include circuit clotting, the most frequent cause for CRRT interruption. Vascular access and circuit management were found to be major determinants of performance efficiency. Anticoagulation required to prevent clotting has the downside of increasing the risk of bleeding, especially in the setting of overdosage. Hence, a delicate balance needs to be maintained consistently. METHODS This study explores the adequacy of non-anticoagulation measures in the prevention of circuit clotting. A comprehensive literature search was conducted using PubMed/Medline and Embase databases to include all relevant studies. FINDINGS The most-effective CRRT catheter would be made of nonthrombogenic material, noncuffed and nontunneled with separate lumens for arterial and venous blood. Further, studies show that blood flow during the process is optimized at 200 ml/min, which can be lowered in the pediatric population due to more narrow catheters. Platelet count and hematocrit need to be closely monitored as levels above 450,000 × 106 /L and 0.40, respectively, increase risk of clotting. Predilution is a non-anticoagulation technique to reduce the risk of clotting by returning replacement solution to the blood before it reaches the filter. Also, biocompatible membranes such as polyacrylonitrile or polysulfone activate the coagulation cascade significantly less than the conventional cellulose-based membranes, thereby reducing clotting chances. DISCUSSIONS With the advent of such techniques and maneuvers, anticoagulation can be efficiently maintained in patients undergoing CRRT without increasing the risk of bleeding.
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Affiliation(s)
- Rupesh Raina
- Akron Nephrology Associates, Cleveland Clinic Akron General Medical Center, Akron, Ohio, USA.,Department of Nephrology, Akron Children's Hospital, Akron, Ohio, USA
| | - Sidharth Sethi
- Pediatric Nephrology, Kidney Institute, Medanta, The Medicity Hospital, Gurgaon, Haryana, India
| | - Amrit Khooblall
- Akron Nephrology Associates, Cleveland Clinic Akron General Medical Center, Akron, Ohio, USA.,Department of Nephrology, Akron Children's Hospital, Akron, Ohio, USA
| | - Vijay Kher
- Pediatric Nephrology, Kidney Institute, Medanta, The Medicity Hospital, Gurgaon, Haryana, India
| | - Shweta Deshpande
- Akron Nephrology Associates, Cleveland Clinic Akron General Medical Center, Akron, Ohio, USA.,Department of Nephrology, Akron Children's Hospital, Akron, Ohio, USA
| | - Keval Yerigeri
- Department of Medicine, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Aadi Pandya
- Akron Nephrology Associates, Cleveland Clinic Akron General Medical Center, Akron, Ohio, USA.,Department of Nephrology, Akron Children's Hospital, Akron, Ohio, USA
| | - Nikhil Nair
- Akron Nephrology Associates, Cleveland Clinic Akron General Medical Center, Akron, Ohio, USA.,Department of Nephrology, Akron Children's Hospital, Akron, Ohio, USA
| | - Nithin Datla
- Akron Nephrology Associates, Cleveland Clinic Akron General Medical Center, Akron, Ohio, USA.,Department of Nephrology, Akron Children's Hospital, Akron, Ohio, USA
| | - Mignon McCulloch
- Red Cross War Memorial Children's Hospital, University of Cape Town, Cape Town, South Africa
| | - Timothy Bunchman
- Pediatric Nephrology & Transplantation, Children's Hospital of Richmond at VCU, Richmond, Virginia, USA
| | - Andrew Davenport
- University College London Centre for Nephrology, Division of Medicine, University College London Medical School, Royal Free Hospital, London, UK
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Goto J, Forsberg U, Jonsson P, Matsuda K, Nilsson B, Nilsson Ekdahl K, Henein MY, Stegmayr BG. Interdialytic weight gain of less than 2.5% seems to limit cardiac damage during hemodialysis. Int J Artif Organs 2020; 44:539-550. [PMID: 33339470 PMCID: PMC8366174 DOI: 10.1177/0391398820981385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aims: To investigate if a single low-flux HD induces a rise in cardiac biomarkers and if a change in clinical approach may limit such mechanism. Material and methods: A total of 20 chronic HD patients each underwent three different study-dialyses. Dialyzers (low-flux polysulfone, 1.8 sqm) had been stored either dry or wet (Wet) and the blood level in the venous chamber kept low or high. Laboratory results were measured at baseline, 30 and 180 min, adjusted for the effect of fluid shift. Ultrasound measured microemboli signals (MES) within the return line. Results: Hemodialysis raised cardiac biomarkers (p < 0.001): Pentraxin 3 (PTX) at 30 min (by 22%) and at 180 min PTX (53%), Pro-BNP (15%), and TnT (5%), similarly for all three HD modes. Baseline values of Pro-BNP correlated with TnT (rho = 0.38, p = 0.004) and PTX (rho = 0.52, p < 0.001). The changes from pre- to 180 min of HD (delta-) were related to baseline values (Pro-BNP: rho = 0.91, p < 0.001; TnT: rho = 0.41, p = 0.001; PTX: rho = 0.29, p = 0.027). Delta Pro-BNP (rho = 0.67, p < 0.001) and TnT (rho = 0.38, p = 0.004) correlated with inter-dialytic-weight-gain (IDWG). Biomarkers behaved similarly between the HD modes. The least negative impact was with an IDWG ⩽ 2.5%. Multiple regression analyses of the Wet-High mode does not exclude a relation between increased exposure of MES and factors such as release of Pro-BNP. Conclusion: Hemodialysis, independent of type of dialyzer storage, was associated with raised cardiac biomarkers, more profoundly in patients with higher pre-dialysis values and IDWG. A limitation in IDWG to <2.5% and prolonged ultrafiltration time may limit cardiac strain during HD, especially in patients with cardiovascular risk.
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Affiliation(s)
- Junko Goto
- Institute of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden.,Department of Emergency and Critical Care Medicine, School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Ulf Forsberg
- Institute of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden.,Department of Internal Medicine, Skellefteå County Hospital, Skellefteå, Sweden
| | - Per Jonsson
- Institute of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden
| | - Kenichi Matsuda
- Department of Emergency and Critical Care Medicine, School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Bo Nilsson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Kristina Nilsson Ekdahl
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Linnaeus Centre of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
| | - Michael Y Henein
- Institute of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden
| | - Bernd G Stegmayr
- Institute of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden
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6
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Matsuda K, Fissell R, Ash S, Stegmayr B. Long-Term Survival for Hemodialysis Patients Differ in Japan Versus Europe and the USA. What Might the Reasons Be? Artif Organs 2018; 42:1112-1118. [PMID: 30417399 DOI: 10.1111/aor.13363] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 09/25/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Kenichi Matsuda
- Department of Emergency and Critical Care Medicine, University of Yamanashi School of Medicine, Yamanashi, Japan
| | - Rachel Fissell
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - Stephen Ash
- HemoCleanse Technologies, LLC and Ash Access Technology, Inc, Lafayette, IN, USA
| | - Bernd Stegmayr
- Department of Public Health and Clinical Medicine, Umea University, Umea, Sweden
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7
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Cerebral Gaseous Microemboli are Detectable During Continuous Venovenous Hemodialysis in Critically Ill Patients: An Observational Pilot Study. J Neurosurg Anesthesiol 2018; 29:236-242. [PMID: 26998647 DOI: 10.1097/ana.0000000000000296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Continuous venovenous hemodialysis (CVVHD) may generate microemboli that cross the pulmonary circulation and reach the brain. The aim of the present study was to quantify (load per time interval) and qualify (gaseous vs. solid) cerebral microemboli (CME), detected as high-intensity transient signals, using transcranial Doppler ultrasound. MATERIALS AND METHODS Twenty intensive care unit (ICU group) patients requiring CVVHD were examined. CME were recorded in both middle cerebral arteries for 30 minutes during CVVHD and a CVVHD-free interval. Twenty additional patients, hospitalized for orthopedic surgery, served as a non-ICU control group. Statistical analyses were performed using the Mann-Whitney U test or the Wilcoxon matched-pairs signed-rank test, followed by Bonferroni corrections for multiple comparisons. RESULTS In the non-ICU group, 48 (14.5-169.5) (median [range]) gaseous CME were detected. In the ICU group, the 67.5 (14.5-588.5) gaseous CME detected during the CVVHD-free interval increased 5-fold to 344.5 (59-1019) during CVVHD (P<0.001). The number of solid CME was low in all groups (non-ICU group: 2 [0-5.5]; ICU group CVVHD-free interval: 1.5 [0-14.25]; ICU group during CVVHD: 7 [3-27.75]). CONCLUSIONS This observational pilot study shows that CVVHD was associated with a higher gaseous but not solid CME burden in critically ill patients. Although the differentiation between gaseous and solid CME remains challenging, our finding may support the hypothesis of microbubble generation in the CVVHD circuit and its transpulmonary translocation toward the intracranial circulation. Importantly, the impact of gaseous and solid CME generated during CVVHD on brain integrity of critically ill patients currently remains unknown and is highly debated.
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8
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Jonsson P, Lindmark L, Axelsson J, Karlsson L, Lundberg L, Stegmayr B. Formation of Blood Foam in the Air Trap During Hemodialysis Due to Insufficient Automatic Priming of Dialyzers. Artif Organs 2018. [PMID: 29542180 DOI: 10.1111/aor.13070] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We were encouraged to investigate the reasons for large amounts of foam observed in bloodlines during hemodialysis (HD). Foam was visible in the venous air trap within the Artis Gambro dialysis device. Estimates of the extent of foam were graded (0-no foam, 10-extensive foam) by two persons that were blind to the type of dialyzer used. Thirty-seven patients were involved in the dialysis procedures. Consecutive dialyses were graded using dialyzers from Fresenius Medical Care (CorDiax dialyzers that were used for high flux HD-FX80 and FX100, and for hemodiafiltration-FX1000). The extracorporeal circuit was primed automatically by dialysate using Gambro Artis software 8.15 006 (Gambro, Dasco, Medolla Italy, Baxter, Chicago, IL, USA). The priming volume recommended by the manufacturer was 1100 mL, whereas our center uses 1500 mL. Extensive amounts of blood foam were visual in the air traps. Although the manufacturer recommended extension of priming volume up to 3000 mL, this did not eliminate the foam. Microbubble measurement during HD revealed the air to derive from the dialyzers. When changing to PF210H dialyzers (Baxter) and using a priming volume of 1500 mL, the foam was significantly less (P < 0.01). The extent of foam correlated with the size of the FX-dialyzer surface (P = 0.002). The auto-priming program was updated to version 8.21 by the manufacturer and the extent of foam in the air trap using FX dialyzers was now reduced and there was no longer a difference between FX and PF dialyzers, although less foam was still visible in the venous air trap during several dialyses. In conclusion, this study urgently calls attention to blood foam development in the venous air trap when using Artis devices and priming software 8.15 in combination with Fresenius dialyzers. Updated auto-priming software (version 8.21) of Artis should be requested to reduce the extent of foam for the Fresenius dialyzers. Other interactions may also be present. We recommend further studies to clarify these problems. Meanwhile caution is warranted for the combined use of dialysis devices and dialyzers with incompatible automatic priming.
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Affiliation(s)
- Per Jonsson
- Department of Public Health and Clinical Medicine, University of Umeå, Umeå, Sweden
| | - Lorentz Lindmark
- Department of Public Health and Clinical Medicine, University of Umeå, Umeå, Sweden
| | - Jan Axelsson
- Department of Radiation Science, University of Umeå, Umeå, Sweden
| | - Lars Karlsson
- Department of Public Health and Clinical Medicine, University of Umeå, Umeå, Sweden
| | - Lennart Lundberg
- Department of Public Health and Clinical Medicine, University of Umeå, Umeå, Sweden
| | - Bernd Stegmayr
- Department of Public Health and Clinical Medicine, University of Umeå, Umeå, Sweden
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9
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Affiliation(s)
- Bernd Stegmayr
- Department of Public Health and Clinical Medicine; Umeå University; Umea Sweden
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10
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Stegmayr BG. Sources of Mortality on Dialysis with an Emphasis on Microemboli. Semin Dial 2016; 29:442-446. [DOI: 10.1111/sdi.12527] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Bernd G. Stegmayr
- Department Public Health and Clinical Medicine; Division of Nephrology; Umeå University; Umeå Sweden
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11
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Wagner S, Rode C, Wojke R, Canaud B. Observation of microbubbles during standard dialysis treatments. Clin Kidney J 2015; 8:400-4. [PMID: 26251706 PMCID: PMC4515906 DOI: 10.1093/ckj/sfv051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 06/05/2015] [Indexed: 11/14/2022] Open
Abstract
Background The infusion of microbubbles as a side effect of haemodialysis was repeatedly demonstrated in recent publications, but the knowledge on the source of microbubbles and on microbubble formation is scarce. Methods Microbubbles in the range of 10–500 µm were measured by a non-invasive bubble counter based on a pulsed ultrasonic Doppler system in a non-interventional study of a single centre. Totally, 29 measurements were performed in standard treatments covering a broad range of patient and treatment conditions (types of blood access, treatment modes, blood flow rates and arterial pressures). Results Several possible sources of microbubbles could be identified such as an arterial luer lock connector at negative pressure and remnant bubbles from insufficient priming, but some sources of microbubbles remain unknown. Microbubbles were found in all treatments, haemodialysis (HD) and online haemodiafiltration. The lowest average microbubble rates (17 ± 16 microbubbles per minute) were observed in patients treated by online haemodiafiltration at medium blood flow rates and moderate arterial pressures and the highest average microbubble rates (117 ± 63 microbubbles per minute) at high blood flow rates (550 mL/min) and low arterial pressures (−210 mmHg). Generally, the microbubble rate correlated to both blood flow rate (correlation coefficient r = 0.45) and negative arterial pressure (r = 0.67). Conclusions Microbubbles are a general side effect of HD; origin and pathophysiologic consequences of this phenomenon are not well understood, and deserve further study.
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Affiliation(s)
- Stephan Wagner
- Georg-Haas-Dialysis-Centres, Gemeinschaftspraxis Giessen/Lich , Giessen , Germany
| | - Christiane Rode
- Georg-Haas-Dialysis-Centres, Gemeinschaftspraxis Giessen/Lich , Giessen , Germany
| | - Ralf Wojke
- Fresenius Medical Care, Bad Homburg, Germany
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12
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Keshavarzi G, Simmons A, Yeoh G, Barber T. Effectiveness of microbubble removal in an airtrap with a free surface interface. J Biomech 2015; 48:1237-40. [PMID: 25841295 DOI: 10.1016/j.jbiomech.2015.03.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 02/18/2015] [Accepted: 03/15/2015] [Indexed: 11/30/2022]
Abstract
An end stage renal disease patient will undergo haemodialysis (HD) three or four times a week for four to five hours per session. Because of the chronic nature of the treatment, any minor imperfection in the extracorporeal system may become significant over time. Clinical studies have raised concerns relating to small microbubbles entering HD patients. These bubbles lead to further pathophysiological complications with the size of the bubble being a major factor. Microbubbles of different sizes can be generated throughout the extra-corporeal HD circuit. It is important to understand the possibility of these bubbles passing through the air trap or successfully being removed which indicates the performance of the air trap, the only mechanics of removing air bubbles. Chronic exposure to various sizes of microbubbles was analysed in detail for haemodialysis patients. However, smaller microbubbles are shown to be able to pass our modelled air trap. While studies have reported the presence of bubbles before and after the air trap, because these bubbles are only counted and not tracked, the performance of the air trap for removing different bubble sizes is not understood. Here, the performance of the air trap in filtering bubbles and the possibility of different bubble sizes passing through the air trap with the presence of the free surface interface have been evaluated. The modelled air trap is shown to be ineffective for filtering small micro bubbles.
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Affiliation(s)
- Gholamreza Keshavarzi
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, Australia; School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
| | - Anne Simmons
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Guan Yeoh
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Tracie Barber
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, Australia
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13
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Fulker D, Keshavarzi G, Simmons A, Pugh D, Barber T. Pulsatility Produced by the Hemodialysis Roller Pump as Measured by Doppler Ultrasound. Artif Organs 2015; 39:945-50. [PMID: 25921287 DOI: 10.1111/aor.12469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microbubbles have previously been detected in the hemodialysis extracorporeal circuit and can enter the blood vessel leading to potential complications. A potential source of these microbubbles is highly pulsatile flow resulting in cavitation. This study quantified the pulsatility produced by the roller pump throughout the extracorporeal circuit. A Sonosite S-series ultrasound probe (FUJIFILM Sonosite Inc., Tokyo, Japan) was used on a single patient during normal hemodialysis treatment. The Doppler waveform showed highly pulsatile flow throughout the circuit with the greatest pulse occurring after the pump itself. The velocity pulse after the pump ranged from 57.6 ± 1.74 cm/s to -72 ± 4.13 cm/s. Flow reversal occurred when contact between the forward roller and tubing ended. The amplitude of the pulse was reduced from 129.6 cm/s to 16.25 cm/s and 6.87 cm/s following the dialyzer and venous air trap. This resulted in almost nonpulsatile, continuous flow returning to the patient through the venous needle. These results indicate that the roller pump may be a source of microbubble formation from cavitation due to the highly pulsatile blood flow. The venous air trap was identified as the most effective mechanism in reducing the pulsatility. The inclusion of multiple rollers is also recommended to offer an effective solution in dampening the pulse produced by the pump.
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Affiliation(s)
- David Fulker
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
| | - Gholamreza Keshavarzi
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia.,Department of Nephrology, The Prince of Wales Hospital, Sydney, Australia
| | - Anne Simmons
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
| | - Debbie Pugh
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Tracie Barber
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
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14
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Keshavarzi G, Barber TJ, Yeoh G, Simmons A, Reizes JA. Two-Dimensional Computational Analysis of Microbubbles in Hemodialysis. Artif Organs 2013; 37:E139-44. [DOI: 10.1111/aor.12110] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Gholamreza Keshavarzi
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney; Australia
| | - Tracie J. Barber
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney; Australia
| | - Guan Yeoh
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney; Australia
| | - Anne Simmons
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney; Australia
| | - John A. Reizes
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney; Australia
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Forsberg U, Jonsson P, Stegmayr C, Jonsson F, Nilsson B, Nilsson Ekdahl K, Stegmayr B. A high blood level in the venous chamber and a wet-stored dialyzer help to reduce exposure for microemboli during hemodialysis. Hemodial Int 2013; 17:612-7. [PMID: 23627921 DOI: 10.1111/hdi.12052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During hemodialysis (HD), microemboli develop in the blood circuit of the apparatus. These microemboli can pass through the venous chamber and enter into the patient's circulation. The aim of this study was to investigate whether it is possible to reduce the risk for exposure of microemboli by altering of the treatment mode. Twenty patients on chronic HD were randomized to a prospective cross-over study of three modes of HD: (a) a dry-stored dialyzer (F8HPS, Fresenius, steam sterilized) with a low blood level in the venous chamber (DL), (b) the same dialyzer as above, but with a high level in the venous chamber (DH), and (c) a wet-stored dialyzer (Rexeed, Asahi Kasei Medical, gamma sterilized) with a high blood level (WH). Microemboli measurements were obtained in a continuous fashion during 180 minutes of HD for all settings. A greater number of microemboli were detected during dialysis with the setting DL vs. WH (odds ratio [OR] 4.07, 95% confidence interval [CI] 4.03-4.11, P<0.0001) and DH vs. WH (OR 1.18, 95% CI 1.17-1.19, P<0.0001) and less for DH vs. DL (OR 0.290, 95% CI 0.288-0.293, P<0.0001). These data indicate that emboli exposure was least when using WH, greater with DH, and most with DL. This study shows that using a high blood level in the venous chamber and wet-stored dialyzers may reduce the number of microemboli.
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Affiliation(s)
- Ulf Forsberg
- Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden; Department of Internal Medicine, Skellefteå County Hospital, Skellefteå, Sweden
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Sherman RA. Briefly Noted. Semin Dial 2012. [DOI: 10.1111/j.1525-139x.2012.12019.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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