Correlation between capillary oxygen saturation and small intestinal wall thickness in the equine colic patient

Abstract

The surgical evaluation of haemorrhagic infarcted intestine and the decision for or against bowel resection require a lot of experience and are subjective. The aim of this prospective, clinical study was to examine the correlation between oxygen saturation and small intestinal wall (IW) thickness, using two objective methods. In 22 colicky horses, the blood flow, oxygen saturation and relative amount of haemoglobin were measured intraoperatively via laser Doppler and white light spectroscopy (O2C, oxygen to see, LEA Medizintechnik) at six measuring points (MPs) in small and large intestines. Furthermore, the IW thickness was measured ultrasonographically. Nine of 22 horses had an increased small IW thickness greater than 4 mm (Freeman 2002, Scharner and others 2002, le Jeune and Whitcomb 2014) at measuring point 1 (MP1) (strangulated segment), four horses had a thickened bowel wall at measuring point 3 (MP3) (poststenotic) and one at measuring point 2 (MP2). The oxygen saturation was 0 at MP1 in six horses, at MP3 in two horses and at MP2 (prestenotic) in one. Oxygen saturation and small IW thickness were independent of each other at MP1 and MP2. At MP3, the two parameters were negatively correlated. In summary, it is not possible to draw conclusions about oxygen saturation based on IW thickness.

Measuring tissue oxygen saturation in the orad intestinal segment during equine colic surgery may aid in predicting the occurrence of postoperative ileus

“…26,27 However, this is not very likely in the horses of the current study considering that the MAP and aSO 2 were above critical limits and that there was no correlation between the aSO 2 and tSO 2 or between the MAP and tBF. Contrary to the results of the current study, another study 13 investigating the use of LDFS during colic surgery did not report reduced microperfusion of the orad segment. This discrepancy might be caused by differences in the degree of distention or the amount of bowel manipulation, considering blood flow has been shown to increase significantly during decompression of the intestine.…”

“…12 This has been applied in strangulated and orad segments in equine colic cases, reporting reduced microperfusion in the obstructed segment but not in the orad segment. 13 Furthermore, the ability of LDF to detect ischemic areas in strangulated intestine and to select the proper level of resection was demonstrated in human medicine. 14,15 To the authors' knowledge, no previous studies have documented the blood flow of the orad segment of naturally occurring strangulating diseases combined with histology and postoperative outcome in horses or any other animal species.…”

Impairment of Mesenteric Perfusion as a Marker of Major Bleeding in Trauma Patients

“…The O2C technique unites backscattering spectroscopy and laser-Doppler flowmetry for measuring oxygen saturation, relative Hb, erythrocyte velocity, and relative blood flow in tissues [105][106][107]. Theoretically, intestinal microcirculation and MP could be assessed with O2C; however, the method shares the main limitation of NIRS as the measurements with the O2C probe are possible only up to a depth of few millimeters [108].…”

Intraoperative Control of Hemoglobin Oxygen Saturation in the Intestinal Wall during Anastomosis Surgery

“…Methods such as laser Doppler and white light spectroscopy are used to study the blood oxygen saturation in the intestinal wall [9]. For white light spectroscopy, the authors used the flat probe containing two light sources and two detectors for measuring the scattered light.…”