title: Real-time measurement of rectal mucosal microcirculation during cardiopulmonary bypass.
abstract: OBJECTIVE
  Mesenteric ischemia is still a fatal event after cardiac procedures. No adequate intraoperative methods are available to monitor the gastrointestinal mucosal microcirculation in real-time conditions. The aim of the study was to assess a newly designed microprobe using laser Doppler flowmetry and remission spectroscopy.
  
  
  METHODS
  One-group, prospective, nonrandomized, open, pilot diagnostic study.
  
  
  METHODS
  Monocenter university hospital.
  
  
  METHODS
  50 patients (n = 38 males, 67±6 years) scheduled for cardiopulmonary bypass (CPB) were prospectively included.
  
  
  METHODS
  During anesthetic induction, the transrectal microprobe (30×15 mm) was positioned between the inferior and middle rectal valve (5-8 cm). Time periods were summarized at T1 = pre-CPB, T2 = CPB, T3 = post-CPB.
  
  
  RESULTS
  In 39 of 50 patients, data recruitment with the microprobe was successful. Measurement failures were due to fecal contaminations and probe dislocations. Rectal blood flow and velocity significantly decreased after bypass initiation (T2). Lowest flow rates were recorded after cross-clamp removal and did not recover at the end of bypass (T3). No side effects of the probe were noted.
  
  
  CONCLUSIONS
  The new microprobe allows reproducible, safe, intraoperative, real-time evaluation of the rectal mucosal microcirculation. It could be a useful diagnostic tool to prevent mesenteric ischemia by optimizing extracorporeal circulation in future studies. However, first correlation of rectal blood flow and postoperative events (eg, ischemia, lactate) in a large cohort are necessary.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany. Electronic address: cardiac.surgeon@dr-kiessling.com.
authors.forename: Arndt-H
authors.initials: AH
authors.lastname: Kiessling
authors.affiliation: Clinic of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Reyher
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Philipp
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany.
authors.forename: Andres
authors.initials: A
authors.lastname: Beiras-Fernandez
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany.
authors.forename: Anton
authors.initials: A
authors.lastname: Moritz
mesh_terms: D000368:Aged; D002315:Cardiopulmonary Bypass / Q000379:methods*; D003199:Computer Systems; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000098:blood supply*; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008297:Male; D008833:Microcirculation / Q000502:physiology; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011446:Prospective Studies; D012007:Rectum / Q000098:blood supply*; D012039:Regional Blood Flow / Q000502:physiology
keywords: cardiopulmonary bypass; laser Doppler flowmetry; mesenteric ischemia; microcirculation; mucosa