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

Flowmetry and spectrophotometry for the assessment of intestinal viability in horses with naturally occurring strangulating small intestinal lesions

BACKGROUND

Ancillary diagnostic methods to enhance the accuracy of viability assessment have not been established for use in clinical practice.

OBJECTIVES

To assess intestinal microperfusion measured by Laser Doppler Flowmetry and Spectrophotometry (LDFS) in naturally occurring small intestinal strangulations of different origins and to compare this between viable and non-viable segments.

STUDY DESIGN

Prospective clinical trial.

METHODS

Forty horses undergoing colic surgery for naturally occurring small intestinal strangulations were included. Tissue oxygen saturation (tSO2), haemoglobin (tHB) and blood flow (tBF) were determined by LDFS before and after release of the strangulation. Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia and assessed using a semi-quantitative mucosal injury score (MIS). The LDFS measurements were compared between the different categories of strangulation causes and histopathological injury using parametric and non-parametric tests (p < 0.05).

RESULTS

Strangulations by pedunculated lipomas had lower tBF (13.9 ± 18 arbitrary units [AU]) than epiploic foramen entrapments (65.2 ± 61 AU; CI -1.697 to -0.2498; p = 0.005). Segments with MIS > 5 showed lower tBF during strangulation than segments with MIS < 4 (mean difference 61.1 AU; CI -1.119 to -0.07361; p = 0.03). This did not differ significantly following release of strangulation. Furthermore, there was a positive correlation between the inflammatory cell count and tBF during strangulation (r 0.34; CI 0.01 to 0.60; p = 0.04). The tSO2 and tHB did not differ between the different categories of lesions or injury.

MAIN LIMITATIONS

No biopsies could be taken from the intestinal segments that did not undergo resection. The duration of strangulation could not reliably be ascertained.

CONCLUSIONS

Blood flow measurements in naturally occurring strangulating lesions show a varying degree of ischaemia in different causes of strangulation. Intestinal blood flow measurements prior to release of the strangulation could potentially contribute to the identification of mucosal injury, yet a high individual variability and other contributing factors need to be considered.

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

The majority of potentially preventable mortality in trauma patients is related to bleeding; therefore, early recognition and effective treatment of hemorrhagic shock impose a cardinal challenge for trauma teams worldwide. The reduction in mesenteric perfusion (MP) is among the first compensatory responses to blood loss; however, there is no adequate tool for splanchnic hemodynamic monitoring in emergency patient care. In this narrative review, (i) methods based on flowmetry, CT imaging, video microscopy (VM), measurement of laboratory markers, spectroscopy, and tissue capnometry were critically analyzed with respect to their accessibility, and applicability, sensitivity, and specificity. (ii) Then, we demonstrated that derangement of MP is a promising diagnostic indicator of blood loss. (iii) Finally, we discussed a new diagnostic method for the evaluation of hemorrhage based on exhaled methane (CH₄) measurement. Conclusions: Monitoring the MP is a feasible option for the evaluation of blood loss. There are a wide range of experimentally used methodologies; however, due to their practical limitations, only a fraction of them could be integrated into routine emergency trauma care. According to our comprehensive review, breath analysis, including exhaled CH₄ measurement, would provide the possibility for continuous, non-invasive monitoring of blood loss.

Abdominal Sonographic Evaluation: In the Field, at the Hospital, and After Surgery

Abdominal sonography is currently a routine procedure in the evaluation of colic in the horse. This imaging technique is used in both the assessment of the horse presented in the emergency setting with acute colic and the assessment of the horse presented for chronic or recurrent colic in the nonemergency setting. Sonography for colic evaluation is used by specialists in different disciplines and by general practitioners in the ambulatory and hospital settings. In this review, we will focus on indications and clinical interpretation of findings as well as recent developments in abdominal sonography.

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

During surgery for colon cancer, monitoring of the oxygen saturation of hemoglobin in the tissues under study makes it possible to assess the degree of blood supply to the anastomosis areas of the colon. Adequate blood supply in this area is decisive in terms of the consistency of the anastomosis and can significantly reduce the risk leakage of anastomosis. In this work, we propose a new approach to assessing the hemoglobin oxygen saturation based on measuring both the diffuse reflectance and transmittance spectra of the colon wall tissues. The proposed method is based on the use of two fiber-optic tools for irradiation from both sides—the intestinal lumen and the outside of the intestinal wall. The spectra are recorded from the external side. To determine the degree of hemoglobin saturation, two algorithms, both based on the Taylor series expansion of the coefficient of light attenuation by tissues, are proposed. The results of a clinical study of the proposed approach on volunteers were obtained, allowing to draw a conclusion about the applicability of the approach in a clinical setting.