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  • 1.
    Brännström, Thomas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Ch.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Hultdin, Johan
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Micro embolies of air are deposited in the organs in hemodialysis patients: a case report2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 636-636Article in journal (Other academic)
  • 2.
    Forsberg, Ulf
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Air contamination during medical treatment results in deposits of microemboli in the lungs: an autopsy study2019In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 42, no 9, p. 477-481Article in journal (Refereed)
    Abstract [en]

    Introduction: Microbubbles of air may enter into patients during conventional hemodialysis, infusions of fluids, or by injections. The aim of this study was to investigate whether the air that enters the patient during hemodialysis can be detected in the lungs after death, and if so, whether this may be related to tissue damage. Methods: The material consisted of lung tissue from five chronic hemodialysis patients who died either during (two) or after hemodialysis (range 10 min from start until 3333 min after the last hemodialysis session); as reference group tissue was taken from seven patients who died due to amyotrophic lateral sclerosis. The lung tissue was investigated by microscopy after autopsy using a fluorescein-marked polyclonal antibody against fibrinogen as a marker for clots preformed before death. Results: All five hemodialysis patients had microbubbles of air in the lung tissue, whereas two of seven amyotrophic lateral sclerosis patients had such findings (Fisher's test p = 0.0278, relative risk = 3.5, confidence interval: 1.08-11.3). There were more microbubbles of air/10 randomly investigated microscopic fields of tissue in the hemodialysis patients than the amyotrophic lateral sclerosis patients (Student's test, p < 0.05). All hemodialysis patients had a medium graded extent of pulmonary fibrosis that was not found in any of the ALS patients. The microbubbles of air were surrounded by fibrin as a sign of development of clots around the air bubbles while the patients were still alive. Conclusion: Exposure to microbubbles of air during various treatments such as hemodialysis may result in microemboli. Future studies should clarify whether microbubbles of air contribute to tissue scarring. We suggest preventive measures against the exposure to microbubbles of air during especially repeated exposures such as hemodialysis.

  • 3.
    Forsberg, Ulf
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Christofer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    A high blood level in the air trap reduces microemboli during hemodialysis2012In: Artificial Organs, ISSN 0160-564X, E-ISSN 1525-1594, Vol. 36, no 6, p. 525-529Article in journal (Refereed)
    Abstract [en]

    Previous studies have demonstrated the presence of air microemboli in the dialysis circuit and in the venous circulation of the patients during hemodialysis. In vitro studies indicate that a high blood level in the venous air trap reduces the extent of microbubble formation. The purpose of this study was to examine whether air microbubbles can be detected in the patient's access and if so, whether the degree of microbubble formation can be altered by changing the blood level in the venous air trap. This was a randomized, double-blinded, interventional study of 20 chronic hemodialysis patients. The patients were assigned to hemodialysis with either an elevated or a low blood level in the air trap. The investigator and the patient were blinded to the settings. The numbers of microbubbles were measured at the site of the arteriovenous (AV) access for 2 min with the aid of an ultrasonic Doppler device. The blood level in the air trap was then altered to the opposite setting and a new measurement was carried out after an equilibration period of 30 min. Median (range) for the number of microbubbles measured with the high air trap level and the low air trap level in AV access was 2.5 (0-80) compared with 17.5 (0-77), respectively (P = 0.044). The degree of microbubble formation in hemodialysis patients with AV access was reduced significantly if the blood level in the air trap was kept high. The exposure of potentially harmful air microbubbles was thereby significantly reduced. This measure can be performed with no additional healthcare cost.

  • 4.
    Forsberg, Ulf
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Medicin-geriatriska kliniken, Skellefteå lasarett.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Christofer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Microemboli, developed during haemodialysis, pass the lung barrier and may cause ischaemic lesions in organs such as the brain2010In: Nephrology, Dialysis and Transplantation, ISSN 0931-0509, E-ISSN 1460-2385, Vol. 25, no 8, p. 2691-2695Article in journal (Refereed)
    Abstract [en]

    The infused and returning fluid from HD devices contains air microbubbles that enter the patient without triggering any alarms. These small emboli pass the lung and may cause ischaemic lesions in organs supported by the arterial circuit, such as the brain.

  • 5.
    Johagen, Daniel
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Svenmarker, Pontus
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Department of Biomedical Engineering and Informatics, Umeå University, Umeå, Sweden.
    Svenmarker, Staffan
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    A microscopic view of gaseous microbubbles passing a filter screen2017In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 40, no 9, p. 498-502Article in journal (Refereed)
    Abstract [en]

    Purpose: The aim of this study was to investigate the filtration efficacy of a 38-µm 1-layer screen filter based on Doppler registrations and video recordings of gaseous microbubbles (GME) observed in a microscope.

    Methods: The relative filtration efficacy (RFE) was calculated from 20 (n = 20) sequential bursts of air introduced into the Plasmodex® primed test circuit.

    Results: The main findings indicate that the RFE decreased (p = 0.00), with increasing flow rates (100-300 mL/min) through the filter screen. This reaction was most accentuated for GME below the size of 100 µm, where counts of GME paradoxically increased after filtration, indicating GME fragmentation. For GME sized between 100-250 µm, the RFE was constantly >60%, independently of the flow rate level. The video recording documenting the GME interactions with the screen filter confirmed the experimental findings.

    Conslusions: The 38-µm 1-layer screen filter investigated in this experimental setup was unable to trap gaseous microbubbles effectively, especially for GME below 100 µm in size and in conjunction with high flow rates.

  • 6.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Evaluation of air contamination incidences and in vitro settings and experiences of micro bubbles2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 636-636Article in journal (Other academic)
  • 7.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Eliasson, G
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Blood lines conduct leakage current during haemodialysis: a potential safety risk during first failure, especially for patients with central dialysis catheter as access.2005In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 43, no 6, p. 731-738Article in journal (Refereed)
  • 8.
    Jonsson, Per
    et al.
    Department of Biomedical Engineering, University Hospital, Umeå, Sweden.
    Forsberg, Ulf
    Department of Internal Medicine, University Hospital, Umeå, Sweden.
    Niklasson, Johan
    Department of Internal Medicine, University Hospital, Umeå, Sweden.
    Stegmayr, Bernd G.
    Department of Internal Medicine, University Hospital, Umeå, Sweden.
    Electrical current leakage during hemodialysis may increase blood-membrane interaction2001In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 24, no 3, p. 136-139Article in journal (Refereed)
    Abstract [en]

    During hemodialysis blood - membrane interaction causes complement activation. During dialysis there may be an electrical current leakage to the dialyzer, especially if there is a broken ground or a defect in another electrical device coupled to the patient.

    This study investigated whether an electric current of 1.5 mA DC could alter blood membrane interaction as measured by changes in C3d in the blood. Such a high current leakage could occur because there is no protection in the dialysis machine (Class 1B) against auxiliary current leakage. Such a current could come from a defective external device in contact with the patient during hemodialysis.

    Materials: A dialysis machine (Fresenius 2008C) with a filled blood-line system containing about 350 ml whole blood from each of 8 different donors was used in vitro. Each of the eight test-runs also contained 1000 U added heparin. The dialysis procedure was performed using hemophan membranes (GFS +12, Gambro) with bicarbonate and potassium 3.0 (D210, Gambro) as dialysate. Two electric poles were placed in the blood line, before and after the dialyzer (connected in parallel) and the ground was placed at entry and exit of the dialysate fluid coming from the machine to the dialysis filter. C3d was measured before the start of “dialysis” and at 15, 30, 45 and 60 min, during dialysis. Thereafter the 1.5 mA current was switched on and additional samples were drawn at 75 and 90 min. The mean C3d values were calculated. Paired non-parametric statistical analyses were performed.

    Results: There was a significant and continuous increase in C3d as compared to the “predialysis” level. The increase during 0 to 30 minutes was greater than that from 30 to 60 minutes (p=0.018); the increase in C3d during 60 to 90 min, was greater than that from 30 to 60 min (p=0.018) and there was no difference between the 0 to 30 and the 60 to 90 min increases.

    Conclusions: A current, used in this study, was able to induce a blood membrane interaction during in vitro dialysis. Even a weaker current leakage might have such adverse effects and similar interactions seem possible during regular dialysis depending on the extent of the leakage.

  • 9.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    EVALUATION OF AIR MICRO BUBBLES IN DIALYSIS SYSTEMS IN VITRO2014In: American Journal of Kidney Diseases, ISSN 0272-6386, E-ISSN 1523-6838, Vol. 63, no 5, p. A61-A61Article in journal (Other academic)
  • 10.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Christofer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Response to letter to the editor.2007In: Artif Organs, ISSN 0160-564X, Vol. 31, no 12, p. 913-4Article in journal (Refereed)
  • 11.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Karlsson, M
    Wiklund, U
    Jensen, Steen M
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Measurement of cardiac rhythm in connection to haemodialysis with focus on a possible interference due to leakage current: a pilot study of patients in chronic haemodialysisArticle in journal (Refereed)
  • 12.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lindmark, Lorentz
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Axelsson, Jan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Karlsson, Lars
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Lundberg, Lennart
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Formation of Blood Foam in the Air Trap During Hemodialysis Due to Insufficient Automatic Priming of Dialyzers2018In: Artificial Organs, ISSN 0160-564X, E-ISSN 1525-1594, Vol. 42, no 5, p. 533-539Article in journal (Refereed)
    Abstract [en]

    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 (0no foam, 10extensive 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 HDFX80 and FX100, and for hemodiafiltrationFX1000). 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.

  • 13.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd G
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Current leakage in hemodialysis machines may be a safety risk for patients.2000In: Artificial Organs, ISSN 0160-564X, E-ISSN 1525-1594, Vol. 24, no 12, p. 977-981Article in journal (Refereed)
  • 14.
    Stegmayr, B. G.
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forsberg, U.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, C. J.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, P.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    In vitro testing of prevailing materials and initial clinical findings2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 636-636Article in journal (Refereed)
    Abstract [en]

    Objectives: During HD previous studies have shown that especially micro bubbles of air may pass the air detector. These studies focused to analyse in vitro if the air trap of various producers may contribute to the presence of micro embolic counts in the fluid that has passed the air trap detector. In addition another in vitro study analysed if the dialyzer by itself may contribute to these contaminations. In parallel a clinical study was performed to evaluate if findings during in vitro tests could be found to some extent during chronic hemodialysis. If such contamination was present how frequent this would be and would it be a greater risk at the start or the end of dialysis.

    Methods: A ultrasound probe was placed on the venous dialysis tube after the air detector and venous chamber (Hatteland, Norway).

    Results:The studies verified previous in vitro studies with micro embolic counts that pass the air trap without inducing an alarm. Fewer embolic signals were detected in the in vitro studies when using a high level of the fluid in the air trap and when using a wet dialyzers. In the clinical studies high counts were present both at the first period as well as the last period of hemodialysis.

    Conclusions: These studies verify the finding of embolic counts in various extents in various in vitro settings, but also verify the presence of such counts in the dialysis tubes after the air trap in clinical routine hemodialysis. Further studies are warranted to clarify how to prevent patients from such problems and to clarify if the counts are clinically relevant.

  • 15.
    Stegmayr, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Brännström, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Christofer
    Hultdin, Johan
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry.
    Microbubbles of air may occur in the organs of hemodialysis patients2012In: ASAIO journal (1992), ISSN 1058-2916, E-ISSN 1538-943X, Vol. 58, no 2, p. 177-179Article in journal (Refereed)
    Abstract [en]

    During hemodialysis (HD), blood that passes the dialysis device gets loaded with microbubbles (MB) of air that are returned to the patient without inducing an alarm. The aim with this study was to clarify if these signals are due to microembolies of air, clots, or artifacts, by histopathology of autopsy material of HD patients. These first results are from a patient on chronic HD. Due to pulmonary edema he was ultrafiltered. Within 30 minutes after the start, he suffered from a cardiac arrest and died. Autopsy verified the clinical findings. Microscopic investigation verified microembolies of air that were surrounded by fibrin in the lungs, brain, and heart. The study verified that MBs can enter the blood during HD and are trapped in the lungs. In addition, MBs pass the pulmonary capillaries and enter the arterial part of the body and are dispersed throughout the body. This can contribute to organ damage and be part of the poor prognoses seen in HD patients. Data support the importance to reduce MBs in the dialysis circuit.

  • 16.
    Stegmayr, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Christofer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    The sensor in the venous chamber does not prevent passage of air bubbles during hemodialysis2007In: Artificial Organs, ISSN 0160-564X, E-ISSN 1525-1594, Vol. 31, no 2, p. 162-166Article in journal (Refereed)
  • 17.
    Stegmayr, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Mahmood, Dana
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    A significant proportion of patients treated with citrate containing dialysate need additional anticoagulation2013In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 36, no 1, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Background: The blood membrane interaction induced during hemodialysis (HD) activates the coagulation system. To prevent clotting and to maintain dialyzer patency, an anticoagulant such as tinzaparin is used. To increase patency of the dialyzers and to reduce the risk of bleeding related to anticoagulation, citrate-containing dialysate has been introduced in Europe.

    Purpose: The aim of this randomized, cross-over study was to investigate if citrate-containing dialysate was safe and efficient enough as the sole anticoagulation agent in chronic HD patients.

    Material and Methods: In this clinical setting, 23 patients on chronic hemodialysis were randomized in a cross-over design using anticoagulation either by LMWH-tinzaparin or citrate (Cit) as dialysate (22 completed the study). The study included paired analyses of subjective patency, ionized calcium (iCa), urea reduction rate. During Cit-HD, the iCa was significantly more reduced with prolonged time. The lowest iCa measured was 0.96 mmol/l. The median iCa after 210 min of HD was 1.02 for Cit-Hd and 1.16 for standard tinzaparin-HD (p = 0.001). Patency of dialyzers was estimated as clear in 14%, stripes of clotted fibers in 36%, and a red filter in 32% of HD session. The addition of approximately 40% of the patients’ usual dose of tinzaparin was given to 7 of the patients as a bolus. Four Cit-HD sessions had to be interrupted prematurely due to clotting.

    Conclusion: A significant proportion of patients treated with citrate-containing dialysate need additional anticoagulation.

  • 18.
    Stegmayr, Christofer J
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Development of air micro bubbles in the venous outlet line: an in vitro analysis of various air traps used for hemodialysis.2007In: Artif Organs, ISSN 0160-564X, Vol. 31, no 6, p. 483-8Article in journal (Refereed)
  • 19.
    Stegmayr, Christoffer
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Hemodialysis dialyzers contribute to contamination of air microemboli that bypass the alarm system in the air trap.2008In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 31, no 4, p. 317-22Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Previous studies have shown that micrometer-sized air bubbles are introduced into the patient during hemodialysis. The aim of this study was to investigate, in vitro, the influence of dialysis filters on the generation of air bubbles. METHODS: Three different kind of dialyzers were tested: one high-flux FX80 dry filter (Fresenius Medical Care AG&Co. KGaA, Bad Homburg, Germany), one low-flux F8HPS dry filter (Fresenius Medical Care AG&Co. KGaA, Bad Homburg, Germany) and a wet-stored APS-18u filter (Asahi Kasei Medical, Tokyo, Japan). The F8HPS was tested with pump flow ranging between 100 to 400 ml/min. The three filters were compared using a constant pump flow of 300 ml/min. Measurements were performed using an ultrasound Doppler instrument. RESULTS: In 90% of the series, bubbles were measured after the outlet line of the air trap without triggering an alarm. There were significantly more bubbles downstream than upstream of the filters F8HPS and FX80, while there was a significant reduction using the APS-18u. There was no reduction in the number of bubbles after passage through the air trap versus before the air trap (after the dialyzer). Increased priming volume reduced the extent of bubbles in the system. CONCLUSIONS: Data indicate that the air trap does not prevent air microemboli from entering the venous outlet part of the dialysis tubing (entry to the patient). More extended priming of the dialysis circuit may reduce the extent of microemboli that originate from dialysis filters. A wet filter may be favorable instead of dry-steam sterilized filters.

  • 20.
    Ulf, Forsberg
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Christofer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Nilsson, Bo
    Nilsson Ekdahl, Kristina
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    A high blood level in the venous chamber and a wet-stored dialyzer help to reduce exposure for microemboli during hemodialysis2013In: Hemodialysis International, ISSN 1492-7535, E-ISSN 1542-4758, Vol. 17, no 4, p. 612-617Article in journal (Refereed)
    Abstract [en]

    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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