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Dive into the research topics where Ulf Forsberg is active.

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Featured researches published by Ulf Forsberg.


Nephrology Dialysis Transplantation | 2010

Microemboli, developed during haemodialysis, pass the lung barrier and may cause ischaemic lesions in organs such as the brain

Ulf Forsberg; Per Jonsson; Christofer Stegmayr; Bernd Stegmayr

BACKGROUND Chronic haemodialysis (HD) may relieve some medical problems of terminal uraemia, but the life expectancy of patients is still significantly shortened, and there is a greatly increased morbidity. This includes pulmonary morbidity and chronic central nervous system (CNS) abnormalities. Previous studies have shown that a considerable amount of air microbubbles emanate within the blood lines of the dialysis device and pass the air detector without sounding an alarm. The aim of this study was to investigate whether microemboli can pass to the patient and whether they could be detected in the carotid artery. METHODS A total of 54 patients on chronic HD (16 with central dialysis catheter) were investigated with an ultrasound detector (Hatteland, Røyken, Norway) for the presence of microemboli at the arteriovenous (AV) fistula/graft and at the common carotid artery before and during HD. Measurements were taken for 2 and 5 min, respectively. Non-parametric paired statistics were used (Wilcoxon). RESULTS The median number (range) and mean +/- SD of microembolic signals detected at the AV access site before commencing dialysis and during HD were 0 (0-3) and 0.2+/- 0.5 versus 4 (0-85) and 13.5 +/- 20 (P = 0.000); at the carotid artery, 1 (0-14) and 1.7 +/- 2.9 versus 2 (0-36) and 3.5 +/- 5.8 (P = 0.008). CONCLUSIONS 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.


Artificial Organs | 2012

A High Blood Level in the Air Trap Reduces Microemboli During Hemodialysis

Ulf Forsberg; Per Jonsson; Christofer Stegmayr; Bernd Stegmayr

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 patients 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.


Asaio Journal | 2012

Microbubbles of air may occur in the organs of hemodialysis patients.

Bernd Stegmayr; Thomas Brännström; Ulf Forsberg; Per Jonson; Christofer Stegmayr; Johan Hultdin

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.


Hemodialysis International | 2013

A high blood level in the venous chamber and a wet-stored dialyzer help to reduce exposure for microemboli during hemodialysis

Ulf Forsberg; Per Jonsson; Christofer Stegmayr; Fredrik Jonsson; Bo Nilsson; Kristina Nilsson Ekdahl; Bernd Stegmayr

During hemodialysis (HD), microemboli develop in the blood circuit of the apparatus. These microemboli can pass through the venous chamber and enter into the patients 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.


International Journal of Artificial Organs | 2001

Electrical current leakage during hemodialysis may increase blood-membrane interaction

Per Jonsson; Ulf Forsberg; J Niklasson; Bernd Stegmayr

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.


International Journal of Artificial Organs | 2011

In vitro testing of prevailing materials and initial clinical findings

Bernd Stegmayr; Ulf Forsberg; Christofer Stegmayr; Per Jonsson

Evaluation of air contamination incidences and in vitro settings and experiences of micro bubblesThe use of citrate-containing dialysate for anticoagulation in hemodialysis (hd). report of clinical experienceK1 (EI0154) AGES IN HEMODIALYSIS: TISSUEAND PLASMAAUTOFLUORESCENCE R. Graaff1, S. Arsov1, L. Trajceska4, P. Dzekova4, G.E. Engels1, M. Koetsier1, W. van Oeveren1, L Lundberg5, S. Assa2, C.F.M. Franssen2, A.J. Smit3, G. Rakhorst1, A. Sikole2, B. Stegmayr5 1Dept. of Biomedical Engineering, 2Internal Medicine, Div. Nephrology and 3Div. Vascular Medicine, University Medical Center Groningen, Groningen, The Netherlands; 4Department of Nephrology, University Clinic of Nephrology, Skopje, R. Macedonia; 5Department of Internal Medicine, University Hospital, Umea, SwedenObjectives: 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 ...Artificial Kidney – Uremic Toxins – SYMPOSIUM, 606 Smart and Responsive Biomaterials – SYMPOSIUM, 607 Cardiovascular General 1: Devices – GENERAL SESSION, 608 Ambulatory Blood Processing – SYMPOSIUM, 610 Animal Models for Tissue Engineering – SYMPOSIUM, 610 Cardiovascular General 2: Devices Interaction – GENERAL SESSION, 612 Artificial Muscle for Internal Organ – SYMPOSIUM, 613 Functionalized Biomaterials – SYMPOSIUM, 614 Cardiovascular General 3: Physiology and Pump Control – GENERAL SESSION, 615 Vascular Access in Hemodialysis – SYMPOSIUM, 617 Polymeric Membranes/Blood Interfaces – SYMPOSIUM, 618 Nano and Micro Technology: Driving the Future of Organ Recovery & Development – SYMPOSIUM, 619 Roadbumps for Tissue-Engineering Artificial Organs – SYMPOSIUM, 621 Artificial Liver GENERAL SESSION, 621 Tissue Engineering Approaches – SYMPOSIUM, 622 Cardiovascular General 4: Cardiopulmonary – GENERAL SESSION, 624 Artificial Kidney Dialysis – SYMPOSIUM, 625 Tissue Engineering of Skin: Creating a New Bio-Artificial Organ for Clinical Application – SYMPOSIUM, 627 Cardiovascular General 5: Device & Biology – GENERAL SESSION, 628 Citrate Anticoagulation A Future Option for Extracorporeal Blood Purification – SYMPOSIUM, 629 Latest Advances in Preventive and Regenerative Medicine Technologies – SYMPOSIUM, 630 Intra-Aortic Balloon Pump as a Cardiac Assist Device – SYMPOSIUM, 631 Artificial Organ Transplantation – SYMPOSIUM, 632 New Biomaterials and Scaffolds – SYMPOSIUM, 633 Modelling of Cardiovascular and Pulmonary Function in Regard to Clinical Applications – SYMPOSIUM, 634 Artificial Kidney Dialysis Techniques – SYMPOSIUM, 635 Natural Based Polymeric Biomaterials and Composites for Regenerative Medicine – SYMPOSIUM, 637 Partial Cardiac Support in Shortand Long-Term Application – SYMPOSIUM, 638 Artificial Organs – Practical Applications – GENERAL SESSION, 639 Non-Destructive Techniques to Monitor 3D In Vitro Tissue Engineering Constructs – SYMPOSIUM, 640 Stent and Vascular Prosthesis – GENERAL SESSION, 641 Dialysis Techniques Access – GENERAL SESSION, 643 Scaffolds for TE Via Electrospinning-Structures and Biomaterials – SYMPOSIUM, 644 Drug Delivery Systems – GENERAL SESSION, 646 “Approval Procedures for Medical Devices: Facts, Figures and Basic Rules Seen from Different Continental Perspectives – Artificial Organs and Society: Recent Trends in Japan”, 647K1 (EI0154) AGES IN HEMODIALYSIS: TISSUEAND PLASMAAUTOFLUORESCENCE R. Graaff1, S. Arsov1, L. Trajceska4, P. Dzekova4, G.E. Engels1, M. Koetsier1, W. van Oeveren1, L Lundberg5, S. Assa2, C.F.M. Franssen2, A.J. Smit3, G. Rakhorst1, A. Sikole2, B. Stegmayr5 1Dept. of Biomedical Engineering, 2Internal Medicine, Div. Nephrology and 3Div. Vascular Medicine, University Medical Center Groningen, Groningen, The Netherlands; 4Department of Nephrology, University Clinic of Nephrology, Skopje, R. Macedonia; 5Department of Internal Medicine, University Hospital, Umeå, SwedenDoes the advanced glycation end-products (ages) food intake influence mortality in dialysis patients?


International Journal of Artificial Organs | 2011

Micro embolies of air are deposited in the organs in hemodialysis patients : a case report

Thomas Brännström; Ulf Forsberg; Per Jonsson; Ch. Stegmayr; Johan Hultdin; Bernd Stegmayr

Evaluation of air contamination incidences and in vitro settings and experiences of micro bubblesThe use of citrate-containing dialysate for anticoagulation in hemodialysis (hd). report of clinical experienceK1 (EI0154) AGES IN HEMODIALYSIS: TISSUEAND PLASMAAUTOFLUORESCENCE R. Graaff1, S. Arsov1, L. Trajceska4, P. Dzekova4, G.E. Engels1, M. Koetsier1, W. van Oeveren1, L Lundberg5, S. Assa2, C.F.M. Franssen2, A.J. Smit3, G. Rakhorst1, A. Sikole2, B. Stegmayr5 1Dept. of Biomedical Engineering, 2Internal Medicine, Div. Nephrology and 3Div. Vascular Medicine, University Medical Center Groningen, Groningen, The Netherlands; 4Department of Nephrology, University Clinic of Nephrology, Skopje, R. Macedonia; 5Department of Internal Medicine, University Hospital, Umea, SwedenObjectives: 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 ...Artificial Kidney – Uremic Toxins – SYMPOSIUM, 606 Smart and Responsive Biomaterials – SYMPOSIUM, 607 Cardiovascular General 1: Devices – GENERAL SESSION, 608 Ambulatory Blood Processing – SYMPOSIUM, 610 Animal Models for Tissue Engineering – SYMPOSIUM, 610 Cardiovascular General 2: Devices Interaction – GENERAL SESSION, 612 Artificial Muscle for Internal Organ – SYMPOSIUM, 613 Functionalized Biomaterials – SYMPOSIUM, 614 Cardiovascular General 3: Physiology and Pump Control – GENERAL SESSION, 615 Vascular Access in Hemodialysis – SYMPOSIUM, 617 Polymeric Membranes/Blood Interfaces – SYMPOSIUM, 618 Nano and Micro Technology: Driving the Future of Organ Recovery & Development – SYMPOSIUM, 619 Roadbumps for Tissue-Engineering Artificial Organs – SYMPOSIUM, 621 Artificial Liver GENERAL SESSION, 621 Tissue Engineering Approaches – SYMPOSIUM, 622 Cardiovascular General 4: Cardiopulmonary – GENERAL SESSION, 624 Artificial Kidney Dialysis – SYMPOSIUM, 625 Tissue Engineering of Skin: Creating a New Bio-Artificial Organ for Clinical Application – SYMPOSIUM, 627 Cardiovascular General 5: Device & Biology – GENERAL SESSION, 628 Citrate Anticoagulation A Future Option for Extracorporeal Blood Purification – SYMPOSIUM, 629 Latest Advances in Preventive and Regenerative Medicine Technologies – SYMPOSIUM, 630 Intra-Aortic Balloon Pump as a Cardiac Assist Device – SYMPOSIUM, 631 Artificial Organ Transplantation – SYMPOSIUM, 632 New Biomaterials and Scaffolds – SYMPOSIUM, 633 Modelling of Cardiovascular and Pulmonary Function in Regard to Clinical Applications – SYMPOSIUM, 634 Artificial Kidney Dialysis Techniques – SYMPOSIUM, 635 Natural Based Polymeric Biomaterials and Composites for Regenerative Medicine – SYMPOSIUM, 637 Partial Cardiac Support in Shortand Long-Term Application – SYMPOSIUM, 638 Artificial Organs – Practical Applications – GENERAL SESSION, 639 Non-Destructive Techniques to Monitor 3D In Vitro Tissue Engineering Constructs – SYMPOSIUM, 640 Stent and Vascular Prosthesis – GENERAL SESSION, 641 Dialysis Techniques Access – GENERAL SESSION, 643 Scaffolds for TE Via Electrospinning-Structures and Biomaterials – SYMPOSIUM, 644 Drug Delivery Systems – GENERAL SESSION, 646 “Approval Procedures for Medical Devices: Facts, Figures and Basic Rules Seen from Different Continental Perspectives – Artificial Organs and Society: Recent Trends in Japan”, 647K1 (EI0154) AGES IN HEMODIALYSIS: TISSUEAND PLASMAAUTOFLUORESCENCE R. Graaff1, S. Arsov1, L. Trajceska4, P. Dzekova4, G.E. Engels1, M. Koetsier1, W. van Oeveren1, L Lundberg5, S. Assa2, C.F.M. Franssen2, A.J. Smit3, G. Rakhorst1, A. Sikole2, B. Stegmayr5 1Dept. of Biomedical Engineering, 2Internal Medicine, Div. Nephrology and 3Div. Vascular Medicine, University Medical Center Groningen, Groningen, The Netherlands; 4Department of Nephrology, University Clinic of Nephrology, Skopje, R. Macedonia; 5Department of Internal Medicine, University Hospital, Umeå, SwedenDoes the advanced glycation end-products (ages) food intake influence mortality in dialysis patients?


Artificial Organs | 2007

Air Bubbles Pass the Security System of the Dialysis Device Without Alarming

Per Jonsson; Lars Karlsson; Ulf Forsberg; Margareta Gref; Christofer Stegmayr; Bernd Stegmayr


Artificial Organs | 2007

The sensor in the venous chamber does not prevent passage of air bubbles during hemodialysis.

Bernd Stegmayr; Ulf Forsberg; Per Jonsson; Christofer Stegmayr


Artificial Organs | 2007

Development of air micro bubbles in the venous outlet line : an in vitro analysis of various air traps used for hemodialysis.

Christofer Stegmayr; Per Jonsson; Ulf Forsberg; Bernd Stegmayr

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