title: Inferior mesenteric venous sampling to detect colonic ischemia: a comparison with laser Doppler flowmetry and photoplethysmography.
abstract: OBJECTIVE
  No single method has been identified that accurately and reliably detects patients with impending bowel infarction during aortic reconstruction. Serial sampling of blood gas from the inferior mesenteric vein (IMV) for detecting colonic ischemia was compared with two previously described techniques: laser Doppler flowmetry (LDF) and photoplethysmography.
  
  
  METHODS
  Nine dogs underwent induced partial colonic ischemia followed by complete ischemia. Serial IMV blood gas measurements were obtained at four intervals: baseline, partial ischemia, complete ischemia, and reperfusion. Simultaneous direct colon wall LDF and PPG measurements also were obtained.
  
  
  RESULTS
  Changes in pH, Po2, O2 saturation, and Pco2 demonstrated progressive acidosis, hypoxemia, and hypercapnia in association with progressive arterial occlusion and a reversal of these trends toward baseline after restoration of flow. The absence of a pulsatile photoplethysmography tracing and oxygen saturation less than 90% were predictive of altered perfusion but could not differentiate partial from complete ischemia. Although the differences in mean LDF values were statistically different during ischemia and reperfusion, there was considerable variability between each measurement.
  
  
  CONCLUSIONS
  Analysis of blood gas from the IMV and pulse oximetry are useful techniques for detecting colonic ischemia, but only the former can distinguish partial from complete ischemia. The variability in colonic measurements with LDF limits its usefulness for detecting levels of colonic perfusion.
authors.affiliation: Department of General Surgery, University of Florida, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Avino
authors.forename: W A
authors.initials: WA
authors.lastname: Oldenburg
authors.forename: P
authors.initials: P
authors.lastname: Gloviczki
authors.forename: V M
authors.initials: VM
authors.lastname: Miller
authors.forename: L J
authors.initials: LJ
authors.lastname: Burgart
authors.forename: E J
authors.initials: EJ
authors.lastname: Atkinson
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D003106:Colon / Q000098:blood supply*; D004285:Dogs; D006863:Hydrogen-Ion Concentration; D007511:Ischemia / Q000097:blood / Q000175:diagnosis*; D017078:Laser-Doppler Flowmetry; D008642:Mesenteric Veins; D010092:Oximetry; D017156:Photoplethysmography