title: Detection of microemboli in the subclavian vein of patients undergoing haemodialysis and haemodiafiltration using pulsed Doppler ultrasound.
abstract: BACKGROUND
  The pathophysiology leading to pulmonary side effects during haemodialysis and haemodiafiltration is not yet fully understood. Chronic microembolization, which can be demonstrated by pulsed Doppler ultrasound, may be one cause.
  
  
  METHODS
  The study cohort consisted of 24 long-term dialysis patients undergoing haemodialysis (n=21) and online-haemodiafiltration (n=3), respectively. The subclavian vein downstream to the venous access was investigated during different phases of the procedure using a 2-MHz pulsed ultrasound device.
  
  
  RESULTS
  In all periods investigated (connection, dialysis, disconnection), numerous microembolic signals (MES) were found in the subclavian vein. The numbers of MES detected during haemodiafiltration (314-709 MES per 10 min) were higher than during haemodialysis (0-81 MES per 10 min).
  
  
  CONCLUSIONS
  The composition (gaseous or solid) and origin (pump, tubing system or shunt) of the microemboli detected remains unclear. Chronic microembolization may be one cause of pulmonary complications of haemodialysis and haemodiafiltration. The detection method described in this article will help us to better understand this process and to determine what role microemboli might play in pulmonary and central nervous system disorders. It may also help to optimize the devices and techniques used.
authors.affiliation: Department of Neurology and. Department of Internal Medicine, University of Münster, Münster, Germany. droste2@uni-muenster.de
authors.forename: Dirk W
authors.initials: DW
authors.lastname: Droste
authors.forename: Karsten
authors.initials: K
authors.lastname: Kühne
authors.forename: Roland M
authors.initials: RM
authors.lastname: Schaefer
authors.forename: E Bernd
authors.initials: EB
authors.lastname: Ringelstein
mesh_terms: D000328:Adult; D000368:Aged; D004617:Embolism / Q000000981:diagnostic imaging* / Q000209:etiology*; D004618:Embolism, Air / Q000000981:diagnostic imaging / Q000209:etiology; D005260:Female; D017583:Hemodiafiltration / Q000009:adverse effects*; D006801:Humans; D020766:Intracranial Embolism / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000209:etiology; D006435:Renal Dialysis / Q000009:adverse effects*; D013350:Subclavian Vein / Q000000981:diagnostic imaging*; D018617:Ultrasonography, Doppler, Pulsed