Evaluation of jejunal microvasculature of healthy anesthetized dogs with sidestream dark field video microscopy

Abstract

OBJECTIVE To determine the feasibility of sidestream dark field (SDF) video microscopy for the evaluation of the jejunal microvasculature of healthy dogs. ANIMALS 30 healthy sexually intact female shelter dogs anesthetized for ovariohysterectomy. PROCEDURES Preoperative physical and clinicopathologic assessments were performed to confirm health status. Then healthy dogs were anesthetized, and the abdomen was incised at the ventral midline for ovariohysterectomy and jejunal microvasculature evaluation. An SDF video microscope imaged the microvasculature of 2 sites of a portion of the jejunum, and recorded videos were analyzed with software capable of quantitating parameters of microvascular health. Macrovascular parameters (heart rate, respiratory rate, and hemoglobin oxygen saturation) were also recorded during anesthesia. RESULTS Quantified jejunal microvascular parameters included valid microvascular density (mean ± SD, 251.72 ± 97.10 μm/mm), RBC-filling percentage (66.96 ± 8.00%), RBC column width (7.11 ± 0.72 μm), and perfused boundary region (2.17 ± 0.42 μm). The perfused boundary region and RBC-filling percentage had a significant negative correlation. Strong to weak positive correlations were noted among the perfused boundary regions of small-, medium-, and large-sized microvessels. No significant correlations were identified between microvascular parameters and age, body weight, preoperative clinicopathologic results, or macrovascular parameters. CONCLUSIONS AND CLINICAL RELEVANCE Interrogation of the jejunal microvasculature of healthy dogs with SDF video microscopy was feasible. Results of this study indicated that SDF video microscopy is worth additional investigation, including interrogation of diseased small intestine in dogs.

A quantitative evaluation of the effect of foreign body obstruction and enterectomy technique on canine small intestinal microvascular health

“…The jejunal antimesenteric border of 30 sexually intact, healthy female dogs weighing >15 kg and undergoing surgery for a routine ovariohysterectomy was interrogated using SDF videomicroscopy as previously described 19 …”

“…17,18 Moreover, use on the jejunum of healthy dogs has previously been described and quantitative parameters established. 19 As far as the authors are aware, use on diseased or devitalized canine intestine has not been reported previously. Moreover, although subjective assessment of the effect of sutured enterectomy techniques on the vascular supply has been reported, 10 there is a paucity of data evaluating the effect of staples on the vascular supply, and a quantitative comparison between sutured and stapled enterectomies.…”

“…Use of SDF videomicroscopy with proprietary software has been validated for sublingual interrogation of microvascular health in humans, dogs, and cats in the critical care setting 17,18 . Moreover, use on the jejunum of healthy dogs has previously been described and quantitative parameters established 19 . As far as the authors are aware, use on diseased or devitalized canine intestine has not been reported previously.…”

The microvascular endothelial glycocalyx: An additional piece of the puzzle in veterinary medicine

“…In human patients; measurements of microvascular flow index have been shown to be similar between bowel and sublingual microvasculature ( de Bruin et al, 2016 ). In veterinary species, sidestream dark field video microscopic assessment of jejunal eGlx has been proposed as a marker of jejunal microvascular health in dogs ( Mullen et al, 2020 ), with potential applications that include aiding in the identification of compromised intestine requiring resection. Measurements in all studies in veterinary species were reported to be similar to those obtained in humans.…”

Fluid Therapy and the Microcirculation in Health and Critical Illness

“…These include transmission electron microscopy, (58-60) intravital microscopy, (61,62) microparticle image velocimetry, (63) confocal laser scanning microscopy or atomic force microscopy, (10) twophoton laser scanning microscopy, (64) and videomicroscopy using handheld devices and various imaging technologies (i.e., orthogonal polarization spectroscopy, sidestream dark-field imaging incident dark-field imaging) (56). More recently, in vivo indirect assessments of the glycocalyx have been performed in humans and small animals using the sidestream darkfield microscopic technique in conjunction with specialized, proprietary software that measures the width of the vessel lumen available for red blood cell movement as an indirect assessment of glycocalyx thickness (also known as the perfused boundary region or PBR) (65)(66)(67)(68). If there is damage to the ESL, RBC are able to penetrate further toward the endothelium and the PBR increases (69).…”