Sources of Mortality on Dialysis with an Emphasis on Microemboli

Abstract

Patients on chronic hemodialysis have a shortened survival compared to the general population. There are multiple sources of morbidity and mortality unique to the dialysis population that account for this. Reasons include the effects of blood membrane interactions, intradialytic hypotension, myocardial stunning, excessive interdialytic weight gain, high-flow arteriovenous fistulae, and impaired lipid break down by anticoagulation administered during HD. Another risk factor, not well appreciated, is the occurrence of microemboli of air (microbubbles) during HD. Such microemboli are not effectively removed by the venous air trap and the safety system provides no warning when these small microbubbles enter the venous bloodline of the extra corporeal circuit and then the venous circulation of the patient. Data indicate that the gas emboli are not fully adsorbed and become embedded by fibrin resulting in a combined clot that causes microemboli in the lung. In addition, these microbubbles (of the size of blood corpuscles) can pass the pulmonary circulation into the left heart and then into the general arterial circulation explaining their detection not only in the lungs but also in the brain and heart of patients. Risk factors for such microbubble appearance include the high blood pump speed associated with high-efficiency dialyses. This review will discuss these various issues in relation to the better outcome of patients in Japan and also how to reduce some of these risk factors.

Air contamination during medical treatment results in deposits of microemboli in the lungs: An autopsy study

“…Such progressive microemboli of air thereby may well be one of the reasons for an increased case fatality of hemodialysis patients. 17 The extent of micro-embolic exposure in the dialysis circuit may be reduced by various measures such as keeping a higher fluid level within standard venous chambers and having less extensive blood pump speed. 18 In conclusion, the exposure to MBs during medical treatment may well result in embolic deposits in the lungs.…”

Long‐Term Survival for Hemodialysis Patients Differ in Japan Versus Europe and the USA. What Might the Reasons Be?

“…The less rapid ultrafiltration rates and lower pump speeds that are seen in Japan may also improve survival by reducing the burden of the micro air emboli (MAE) that develop within the extracorporeal circuit (ECC) during dialysis treatments . Currently used dialysis venous chambers and air traps on HD machines do not fully eliminate air bubbles that develop within the tubing system and dialyzer of the ECC, and are then distributed to the patient’s circulation .…”

Will you give my kidney back? Organ restitution in living-related kidney transplantation: ethical analyses

“…(Death HR is 1 (Japan) to 3.78 (USA). )36–38 Of course, it may be because the patient population on dialysis in the USA is older and with multiple comorbidities. In either case, the low mortality rates of dialysis, and difficulty in getting the second kidney quickly, organ restitution may become a future real scenario.…”