Blood and Peritoneal Lactate, Ratio and Difference, and Peritoneal Lactate to Total Solids Ratio for Detection of Intestinal Strangulating Obstructions in Horses.
Authors: Parra-Moyano Leonardo A, Cedeño Alejandro, Darby Shannon, Johnson Jessica P, Gomez Diego E
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary Strangulating obstructions of the equine intestine demand rapid diagnosis to prevent catastrophic tissue damage, yet current diagnostic markers remain imperfect. This retrospective analysis of 282 horses with intestinal obstructions evaluated whether peritoneal fluid lactate (PFL) and its ratios to blood lactate and peritoneal total solids (PFTS) could reliably distinguish ischaemic strangulating obstructions (SO) from simple obstructions in both the small intestine and large colon. A PFL:PFTS ratio of 2.9 provided fair discrimination for small intestinal strangulation (66.7% sensitivity, 78.3% specificity; AUC 0.76), whilst a higher threshold of 3.6 performed better for large colon strangulation (78% sensitivity and specificity; AUC 0.84). However, peritoneal lactate alone and other lactate-derived ratios demonstrated only low-to-moderate sensitivity across both locations. These findings suggest that whilst the PFL:PFTS ratio—particularly the higher threshold for large colon cases—shows promise as a diagnostic aid, it should never be used in isolation; clinicians must integrate peritoneal fluid analysis with clinical presentation, physical examination findings, and the horse's response to initial medical management to confidently identify strangulating lesions requiring surgical intervention.
Read the full abstract on PubMed
Practical Takeaways
- •Peritoneal lactate-to-total solids ratio shows promise for detecting strangulating large colon lesions in horses, but is less reliable for small intestine cases and should never replace clinical judgment
- •A single lactate measurement or ratio cannot definitively rule in or rule out strangulation—always integrate laboratory findings with clinical presentation, physical examination, and response to initial therapy
- •In emergency colic cases, do not delay surgical intervention while awaiting or interpreting lactate results; use these biomarkers as supporting evidence only
Key Findings
- •PFL:PFTS ratio of 2.9 discriminated between small intestine strangulating and non-strangulating obstructions with 66.7% sensitivity and 78.3% specificity (AUC 0.76)
- •PFL:PFTS ratio of 3.6 discriminated between large colon strangulating and non-strangulating obstructions with 78% sensitivity and 81% specificity (AUC 0.84)
- •Peritoneal fluid lactate, PFL:blood lactate difference, and PFL:blood lactate ratio demonstrated only low to moderate sensitivity for predicting ischemic strangulating lesions
- •PFL:PFTS ratio and other lactate-based markers should be interpreted alongside clinical signs and treatment response rather than used as standalone diagnostic tests