title: Use of micro-lightguide spectrophotometry for evaluation of microcirculation in the small and large intestines of horses without gastrointestinal disease.
abstract: OBJECTIVE
  To evaluate the use of a micro-lightguide tissue spectrophotometer for measurement of tissue oxygenation and blood flow in the small and large intestines of horses under anesthesia.
  
  
  METHODS
  13 adult horses without gastrointestinal disease.
  
  
  METHODS
  Horses were anesthetized and placed in dorsal recumbency. Ventral midline laparotomy was performed. Intestinal segments were exteriorized to obtain measurements. Spectrophotometric measurements of tissue oxygenation and regional blood flow of the jejunum and pelvic flexure were obtained under various conditions that were considered to have a potential effect on measurement accuracy. In addition, arterial oxygen saturation at the measuring sites was determined by use of pulse oximetry.
  
  
  RESULTS
  12,791 single measurements of oxygen saturation, relative amount of hemoglobin, and blood flow were obtained. Errors occurred in 381 of 12,791 (2.98%) measurements. Most measurement errors occurred when surgical lights were directed at the measuring site; covering the probe with the surgeon's hand did not eliminate this error source. No measurement errors were observed when the probe was positioned on the intestinal wall with room light, at the mesenteric side, or between the mesenteric and antimesenteric side. Values for blood flow had higher variability, and this was most likely caused by motion artifacts of the intestines.
  
  
  CONCLUSIONS
  The micro-lightguide spectrophotometry system was easy to use on the small and large intestines of horses and provided rapid evaluation of the microcirculation. Results indicated that measurements should be performed with room light only and intestinal motion should be minimized.
authors.affiliation: Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, 30559 Hannover, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Reichert
authors.forename: Sabine B R
authors.initials: SB
authors.lastname: Kästner
authors.forename: Klaus
authors.initials: K
authors.lastname: Hopster
authors.forename: Karl
authors.initials: K
authors.lastname: Rohn
authors.forename: Anna K
authors.initials: AK
authors.lastname: Rötting
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary; D000818:Animals; D044682:Colon, Ascending / Q000098:blood supply; D005260:Female; D006439:Hemodynamics; D006454:Hemoglobins / Q000032:analysis; D006736:Horses / Q000033:anatomy & histology / Q000502:physiology*; D007422:Intestines / Q000098:blood supply*; D007583:Jejunum / Q000098:blood supply; D008297:Male; D008833:Microcirculation; D010092:Oximetry / Q000662:veterinary; D010100:Oxygen / Q000097:blood / Q000378:metabolism; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D013053:Spectrophotometry / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*
chemical_list: D006454:Hemoglobins; D010100:Oxygen