title: Changes in skeletal muscle microcirculation after a hemodialysis session correlates with adequacy of dialysis.
abstract: BACKGROUND
  Monitoring of the microcirculation may add additional information in terms of improving the adequacy of hemodialysis (HD) for patients. Withdrawal of liquid and complement activation during a HD session reduces the external pressure on the microcirculation and leads to an increased dilatation of the peripheral capillaries. The purposes of this study were to assess the effect of a single HD or hemodiafiltration session on the thenar microcirculation in patients with end-stage renal disease (ESRD) with or without diabetes, investigate the possible relationship between changes in the microcirculation and adequacy of dialysis (including Kt/V and parameters indicating secondary hyperparathyroidism), and compare microcirculation measurements obtained from patients with ESRD and those from healthy controls.
  
  
  METHODS
  This pilot prospective observational study including eleven patients with ESRD on maintenance HD (nine men of mean age 73±10.5 years, ten [91%] with hypertension), nine patients with ESRD on maintenance hemodiafiltration (six men of mean age 65.5±13.2 years, five [55.5%] with diabetes and four [44.5%] with hypertension), and eight healthy volunteers. Two paired microcirculation assessments were recorded for each HD patient before and after a dialysis session. Near infrared spectroscopy and the vascular occlusion test were used to assess the microcirculation, and blood work samples were collected before and after dialysis when the pump slowed down.
  
  
  RESULTS
  Patients with ESRD showed an increase in thenar cell metabolism at rest after a 4-hour HD session, and changes in cell metabolism correlated with the Kt/V of the session. Pre-dialysis tissue oxygen saturation over the 4-hour HD session correlated with pre-dialysis serum calcium and parathyroid hormones. Vascular reactivity was lower in ESRD patients receiving HD or hemodiafiltration than in healthy controls.
  
  
  CONCLUSIONS
  Improvement in skeletal muscle microcirculation noted after a HD session was related to adequacy of dialysis. Evaluation of the microcirculation may provide additional information for management of patients on HD and identify novel targets for treatment. These preliminary findings need to be tested using a larger data set.
authors.affiliation: First Critical Care Department, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Chrysoula
authors.initials: C
authors.lastname: Pipili
authors.affiliation: First Critical Care Department, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Eirini
authors.initials: E
authors.lastname: Grapsa
authors.affiliation: First Critical Care Department, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Elli-Sophia
authors.initials: ES
authors.lastname: Tripodaki
authors.affiliation: Laboratory of Biochemistry, Evangelismos General Hospital, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Sophia
authors.initials: S
authors.lastname: Ioannidou
authors.affiliation: First Critical Care Department, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Manetos
authors.affiliation: First Critical Care Department, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Parisi
authors.affiliation: First Critical Care Department, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Serafim
authors.initials: S
authors.lastname: Nanas
keywords: end stage renal disease; hemodiafiltration; near infrared spectroscopy; single-pool Kt/V