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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A response to a letter to the editor about a previously published article about the manufacturer's information in regard to the safety issues of microbubbles is presented.

Background: When blood passes the extracorporeal circuit, air microbubbles (MBs) contaminate the blood. Some MBs will end up as microemboli in the lung, heart, and brain. MB exposure has no medical purpose and is considered to be bio-incompatible. Selecting venous chambers with a high removal rate of MBs is warranted to reduce the risks of air bio-incompatibility. The primary aim was to compare the Fresenius 5008 (F5008-VC) and the Emboless ® (Emboless-VC) venous chambers regarding the elimination of MBs in the return bloodline during hemodialysis (HD)., Methods: Twenty patients underwent 80 sessions of cross-over HD using both the F5008-VC and the Emboless-VC randomized such that half started with the F5008-VC and half with the Emboless-VC. For 32 of the 80 sessions, measurements were also performed during hemodiafiltrations (HDF) after the initial HD. MBs were measured with an ultrasound device (within the size range of 20-500 µm) at the "inlet" and "outlet" bloodline of the venous chambers. The Wilcoxon pairwise test compared the percentage of MB elimination between venous chambers., Results: During HD, the median reduction of MBs for the outlet was 39% with the F5008-VC and 76% with the Emboless-VC ( P  < .001). During HDF, the reduction was 28% with the F5008-VC and 70% with the Emboless-VC ( P  < .001)., Conclusion: Fewer MBs and subsequently fewer microemboli entered the bloodline of the patient using the Emboless-VC compared to the F5008-VC venous chamber during HD and during HDF. Venous chambers with a high removal rate of MBs will reduce the extent of air emboli., Competing Interests: The results presented in this article have not been published previously in whole or in part, except in abstract format. All three authors declare that they are researchers within the frame of Umea University, Sweden, and clinically active within the field of hemodialysis for more than 20 years. The work has been combined with research and development of medical devices. To clarify the value of a patented venous chamber Emboless®, a company was initiated (Embody AB). Sweden's innovation agency Vinnova, MedTech4Health and Region Västerbotten supported the researcher to perform this clinical study to clarify eventual benefits of Emboless®. All authors are stockholders of the Embody AB company. Independent persons performed safety analysis and monitoring., (© The Author(s) 2024. Published by Oxford University Press on behalf of the ERA.)

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., (© The Author(s) 2022. Published by Oxford University Press on behalf of the ERA.)