title: Prevention of dialysis hypotension episodes using fuzzy logic control system.
abstract: BACKGROUND
  Automatic systems for stabilizing blood pressure (BP) during dialysis are few and only control those variables indirectly related to BP. Due to complex BP regulation under dynamic dialysis conditions, BP itself appears to be the most consistent input parameter for a device addressed to preventing dialysis hypotension (DH).
  
  
  METHODS
  An automatic system (ABPS, automatic blood pressure stabilization) for BP control by fluid removal feedback regulation is implemented on a dialysis machine (Dialog Advanced, Braun). A fuzzy logic (FL) control runs in the system, using instantaneous BP as the input variable governing the ultrafiltration rate (UFR) according to the BP trend. The system is user-friendly and just requires the input of two data: critical BP (individually defined as the possible level of DH risk) and the highest UFR applicable (percentage of the mean UFR). We evaluated this system's capacity to prevent DH in 55 RDT hypotension-prone patients. Sessions with (treatment A) and without (treatment B) ABPS were alternated one-by-one for 30 dialysis sessions per patient (674 with ABPS vs 698 without).
  
  
  RESULTS
  Despite comparable treatment times and UF volumes, severe DH appeared in 8.3% of sessions in treatment A vs 13.8% in treatment B (-39%, P=0.01). Mild DH fell non-significantly (-12.3%). There was a similar percentage of sessions in which the planned body weight loss was not achieved and dialysis time was prolonged.
  
  
  CONCLUSIONS
  In conclusion, FL may be suited to interpreting and controlling the trend of a determined multi-variable parameter like BP. The medical knowledge of the patient and the consequent updating of input parameters depending on the patient's clinical conditions seem to be the main factors for obtaining optimal results.
authors.affiliation: Malpighi Nephrology Department, Dialysis & Hypertension Division, Policlinico S. Orsola-Malpighi, Via P. Palagi 9, 40138 Bologna, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Mancini
authors.forename: Emanuele
authors.initials: E
authors.lastname: Mambelli
authors.forename: Mina
authors.initials: M
authors.lastname: Irpinia
authors.forename: Danila
authors.initials: D
authors.lastname: Gabrielli
authors.forename: Carmelo
authors.initials: C
authors.lastname: Cascone
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Conte
authors.forename: Gina
authors.initials: G
authors.lastname: Meneghel
authors.forename: Fosco
authors.initials: F
authors.lastname: Cavatorta
authors.forename: Alessandro
authors.initials: A
authors.lastname: Antonelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Villa
authors.forename: Antonio
authors.initials: A
authors.lastname: Dal Canton
authors.forename: Leonardo
authors.initials: L
authors.lastname: Cagnoli
authors.forename: Filippo
authors.initials: F
authors.lastname: Aucella
authors.forename: Fulvio
authors.initials: F
authors.lastname: Fiorini
authors.forename: Enzo
authors.initials: E
authors.lastname: Gaggiotti
authors.forename: Giorgio
authors.initials: G
authors.lastname: Triolo
authors.forename: Vitale
authors.initials: V
authors.lastname: Nuzzo
authors.forename: Antonio
authors.initials: A
authors.lastname: Santoro
mesh_terms: D001676:Biofeedback, Psychology / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D017143:Fuzzy Logic; D006801:Humans; D007022:Hypotension / Q000209:etiology / Q000517:prevention & control* / Q000523:psychology; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000523:psychology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods*