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than ultrasonographic findings. The ultrasonographic identification of mesenteric vessels along the right body wall has been described in horses with right dorsal displacement and 180° torsion of the large colon (Grenager & Durham, 2011 ; Ness et al., 2012 ), but this ana- tomical location was not included in the FLASH protocol. Similar to the results of Busoni et al. ( 2011 ), no horses with confirmed colon volvulus were included in the present study. Ultrasonographic iden- tification of colonic wall thickening and loss of the normal sacculated appearance of the ventral colon wall have both been reported in cases of large colon volvulus (Abutarbush, 2006 ; Pease et al., 2004 ); these changes would likely be identified in the ventral abdomen lo- cation of the FLASH protocol. Left dorsal displacement of the large colon was suspected in 5 horses in the present study (4 cases were resolved with medical therapy and one was euthanased but with no post- mortem confirmation). Suspicion of this displacement was based on a combination of the rectal examination findings and ul- trasonography findings (presence of large colon lateral and dorsal to the spleen, obscuring visualisation of the left kidney) (Beccati et al., 2011 ; Busoni et al., 2011 ; Santschi et al., 1993 ; Scharner et al., 2015 ). In the absence of surgical or post- mortem findings of left dorsal displacement in these 5 horses, confirmation of this dis- placement was not possible. Some of the horses in this study will have received analge-
sic and/or sedative drugs prior to the ultrasound examination, although the timing of drug administration was not accurately recorded. Although non- steroidal anti- inflammatory drugs are un- likely to have any significant effect on intestinal motility, alpha- 2 adrenergic receptor agonist sedatives such as xylazine, romifidine and detomidine, are known to reduce gastrointestinal motility (Lester et al., 1998 ; Zullina et al., 2011 ). Therefore, the administra- tion of such drugs could have potentially affected the assessment of small intestinal motility, however, it is unlikely that their admin- istration would have had any significant effect on small intestinal distension or wall thickness. Hyoscine butylbromide is also com- monly administered to horses with non- specific signs of colic, and although it would also be expected to reduce intestinal motility, a recent study found that did not significantly reduce small intestinal motility as assessed by ultrasonography or result in small intestinal dilation (Haugaard et al., 2023 ). We therefore suggest that if any of these drugs had been administered shortly before the abdominal ultrasound examination, they are unlikely to have affected the re- sults of the FLASH procedure. There are several limitations to this study. Firstly, only a small
number of colic cases were evaluated, but as a preliminary study the results do indicate a potential value for undertaking the FLASH scanning procedure in the initial examination of equids with colic; further studies with larger numbers of cases are required. Selection bias is likely; not every case of colic presented to the authors over the time period of the study was examined using the FLASH, due to issues with the availability of the scanner and the exclusion of some cases showing violent colic behaviour, or animals where the colic signs abated prior to veterinary examination. The high non- survival
CORRIE ET AL.
rate in this group of animals (37%) suggests that there was a bias towards including animals with more severe forms of colic. The ab- sence of animals affected by certain conditions such as large colon volvulus means that the use of the FLASH procedure could not be evaluated in such cases. The lack of confirmation of the intestinal diseases that caused colic in the horses that died means that the final diagnosis remains suspected in many cases. However, the horses that were euthanised had colic pain that did not respond to standard medical treatments, including analgesia (often repeated doses of an- algesic drugs), suggesting a high likelihood of a catastrophic intes- tinal disease. Another limitation is the caseload, with the relatively high proportion of ponies and older animals, which will very likely have affected the results and the non- survival rate. Our population of equids would be expected to have a relatively high proportion of animals with risk factors for conditions such as strangulation of small intestine by pedunculated lipomas (aged ponies). Different re- sults would be expected in other populations of younger horses of different breeds. In conclusion, the results of this preliminary study support the
value of the FLASH technique in the evaluation of equids with colic in first opinion equine practice, especially for diagnosing small intes- tinal obstructions. Although the portable wireless ultrasound system used in this study was found to be ideally suited for this purpose, the use of other more widely available ultrasound scanners should be similarly effective. However, the use of rectal probes for the FLASH examination might limit the ability to evaluate deeper structures within the abdomen, and further evaluation of these probes for this purpose is needed.
AUTHOR CONTRIBUTIONS Sam Corrie: Data curation; investigation; methodology; project ad- ministration; writing – original draft; writing – review and editing. Kristina Chapman: Investigation; methodology; project administra- tion; writing – original draft; writing – review and editing. Imogen Schofield: Formal analysis; methodology; writing – original draft; writing – review and editing. Tim S. Mair: Conceptualization; data curation; formal analysis; investigation; methodology; project ad- ministration; validation; writing – original draft; writing – review and editing.
FUNDING INFORMATION None.
CONFLICT OF INTEREST STATEMENT No conflicts of interest have been declared.
ETHICS STATEMENT Owner consent was obtained at the time of the clinical examination.
ORCID Kristina Chapman
https://orcid.org/0000-0002-6576-0989 Tim S. Mair
https://orcid.org/0000-0002-9744-9909
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