title: Pump flow changes do not impair sublingual microcirculation during cardiopulmonary bypass.
abstract: OBJECTIVE
  The flow rate of the cardiopulmonary bypass (CPB) pump used in cardiac surgery often undergoes inherent fluctuations ranging from 10% to 20% of its theoretic value. However, the effects of such alterations remain unknown. In the present study, the authors investigated whether such variations could induce changes in the microvascular flow, which is considered a primary indicator of poor perfusion.
  
  
  METHODS
  A prospective, observational, clinical study.
  
  
  METHODS
  A university-affiliated teaching hospital.
  
  
  METHODS
  Thirty adult patients undergoing elective cardiac surgery with CPB.
  
  
  METHODS
  Analysis of the sublingual microcirculation during CPB using a pump flow rate of 80% or 100% of the theoretic value.
  
  
  RESULTS
  Sidestream dark field (SDF) imaging was used to record 2 video clips of the sublingual microcirculation in each patient. The videos were recorded at the same site at 80% and 100% of the theoretic flow rate. Microvascular analysis displaying the De Backer score, the microvascular flow index, the total vessel density, the perfused vessel density, and the proportion of perfused vessels was performed. Moreover, the mean arterial pressure (MAP), SvO(2), and PaCO(2) were evaluated. No significant changes in the measured parameters were noted at the 2 different flow rates.
  
  
  CONCLUSIONS
  Changes in the CPB pump flow rate within 20% (80%-100%) of its theoretic value do not alter the sublingual microcirculation. Thereafter, it is conceivable that during perioperative adjustments of the CPB pump rate, blood flow autoregulation mechanisms are activated so that limited changes in the pump flow can be considered safe not only at the sublingual site but also for the entire microcirculation.
authors.affiliation: Department of Anaesthesia and Intensive Care, Treviso Regional Hospital, Treviso, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Forti
authors.forename: Alessandra
authors.initials: A
authors.lastname: Comin
authors.forename: Nadia
authors.initials: N
authors.lastname: Lazzarotto
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Battistella
authors.forename: Valeria
authors.initials: V
authors.lastname: Salandin
authors.forename: Carlo
authors.initials: C
authors.lastname: Sorbara
mesh_terms: D000368:Aged; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D009060:Mouth Floor / Q000098:blood supply*; D011446:Prospective Studies; D016037:Single-Blind Method; D014741:Video Recording / Q000379:methods