title: Does monitoring of pre-/post-dialyzer pressure difference improve efficiency in intermittent hemodialysis?
abstract: BACKGROUND
  Continuous monitoring of pre-/post-dialyzer pressure difference (DeltaP) is widely used in continuous renal replacement therapies to monitor extracorporeal circuit function. The aim of this study was to verify whether DeltaP may help to identify chronic subclinical worsening of dialysis quality due to incomplete dialyzer clotting in intermittent hemodialysis.
  
  
  METHODS
  Nine chronic hemodialysis patients were enrolled in the study and dialyzed twice (high-flux polysulfone dialyzer) with DeltaP and urea-clearance monitoring: the first session with a standard anticoagulation and the second without. To verify whether a visible clotting of the dialyzer precedes or follows a significant DeltaP increase, we checked the dialyzers for the presence of red clots after a saline flush performed when a 50% increase in DeltaP was registered.
  
  
  RESULTS
  In the second dialysis session after a 50% increase in DeltaP (documented in 7/9 patients), all dialyzers, after saline flush, showed a visible fiber clotting but not a significant reduction (>15%) in urea clearance. In the majority of the patients (6/7), until a few minutes before complete occlusion of the extracorporeal circuit, the urea clearance did not change significantly (-8.9 +/- 12.7%).
  
  
  CONCLUSIONS
  The usual check of the presence or absence of red clots in the dialyzer at the end of the dialysis session is enough, in the absence of red clots, to ensure that dialyzer efficiency is maintained during the whole treatment. Contrary to what is applied in CRRT, a continuous monitoring of DeltaP during intermittent hemodialysis would not significantly help to unmask unnoticed inefficient hemodialysis sessions.
authors.affiliation: Department of Nephrology, Ospedale la Carità Locarno, Locarno, Switzerland. lugabutti@swissonline.ch
authors.forename: Luca
authors.initials: L
authors.lastname: Gabutti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Colucci
authors.forename: Antonio
authors.initials: A
authors.lastname: Martella
authors.forename: Carlo
authors.initials: C
authors.lastname: Schönholzer
authors.forename: Claudio
authors.initials: C
authors.lastname: Marone
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000494:pharmacology / Q000627:therapeutic use; D001777:Blood Coagulation; D019544:Equipment Failure Analysis / Q000379:methods*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D011108:Polymers; D011312:Pressure; D006435:Renal Dialysis / Q000379:methods / Q000592:standards*; D013450:Sulfones
chemical_list: D000925:Anticoagulants; D008567:Membranes, Artificial; D011108:Polymers; D013450:Sulfones; C017662:polysulfone P 1700