title: Microvascular distribution in the ocular conjunctiva and digestive tract in an experimental setting.
abstract: Recently improved microcirculatory imaging techniques, such as orthogonal polarization spectral (OPS) and its technical successor sidestream dark field (SDF) imaging, in handheld devices have allowed a direct observation of the microcirculation at the bedside. Usually a cut-off of 20 µm in diameter is used to differentiate small vessels (mainly capillaries) from large vessels (mainly venules) during this technique. We hypothesized that it was possible to measure the small vessels with a considerably smaller inner diameter.
  
  
  METHODS
  Images of the sublingual, conjunctival, jejunal, and rectal mucosa microcirculation were obtained with SDF videomicroscopy (Microscan®, Microvision Medical, Amsterdam, the Netherlands). Using the validated software, the length and diameter of microvessels were manually traced with a computer-generated line. All vessels were divided into the groups according to the inner diameter.
  
  
  RESULTS
  A total of 156 SDF images of the sublingual, ocular conjunctival, jejunal, and rectal mucosa were taken in 13 pigs. The length of microscopic vessels progressively increased with a decrease in the vessel diameter less than 8 mm in all the lodges, such as sublingual (80.6% of total vessel length), ocular conjunctival (76.5% of total vessel length), jejunal (99.8% of total vessel length), and rectal (97.8% of total vessel length), due to capillary network formation. There was no significant difference in the distribution of vessels from 0 to 10 µm in diameter comparing sublingual and eye conjunctival as well as jejunal and rectal mucosa.
  
  
  CONCLUSIONS
  In pigs, small-diameter microscopic vessels (<10 µm) dominated in all the studied lodges (sublingual, ocular conjunctival, jejunal, and rectal mucosa), and this is evidence to establish a new cut-off for capillaries in microcirculatory analysis of SDF imaging in experimental and clinical studies.
authors.affiliation: Department of Intensive Care, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania. a.pranskunas@gmail.com
authors.forename: Andrius
authors.initials: A
authors.lastname: Pranskūnas
authors.forename: Vidas
authors.initials: V
authors.lastname: Pilvinis
authors.forename: Žilvinas
authors.initials: Ž
authors.lastname: Dambrauskas
authors.forename: Renata
authors.initials: R
authors.lastname: Rasimavičiūtė
authors.forename: Eglė
authors.initials: E
authors.lastname: Milieškaitė
authors.forename: Algimantas
authors.initials: A
authors.lastname: Bubulis
authors.forename: Vincentas
authors.initials: V
authors.lastname: Veikutis
authors.forename: Dinas
authors.initials: D
authors.lastname: Vaitkaitis
authors.forename: E Christiaan
authors.initials: EC
authors.lastname: Boerma
mesh_terms: D000818:Animals; D003228:Conjunctiva / Q000098:blood supply*; D041981:Gastrointestinal Tract / Q000098:blood supply*; D008833:Microcirculation; D055806:Microvessels / Q000033:anatomy & histology*; D013552:Swine