Use of multiple admission variables better predicts intestinal strangulation in horses with colic than peritoneal or the ratio of peritoneal:blood l-lactate concentration.
Authors: Long Alicia E, Southwood Louise L, Morris Tate B, Brandly Jerrianne E, Stefanovski Darko
Journal: Equine veterinary journal
Summary
# Editorial Summary: Predicting Strangulating Intestinal Obstruction in Colicky Horses Early surgical intervention dramatically improves survival in horses with strangulating obstruction, yet identifying these cases within the critical first hours remains clinically challenging. Researchers at a US referral hospital examined whether blood and peritoneal fluid l-lactate concentrations—individually and as a ratio—could reliably predict strangulating lesions in 197 colic cases, and whether combining these markers with other clinical variables might improve diagnostic accuracy. Rather than performing better in isolation, l-lactate measurements showed their true utility only when integrated into multivariable models: the model predicting any strangulating obstruction (AUC 0.91) incorporated marked pain severity, lower rectal temperature, serosanguineous peritoneal fluid, and both the peritoneal-blood l-lactate difference and ratio; the model for small intestinal strangulation specifically benefited from reflux volume, blood l-lactate concentration, serosanguineous fluid, and peritoneal l-lactate concentration. Practitioners should abandon the practice of relying on any single l-lactate parameter or ratio as a diagnostic threshold, instead using these biochemical findings to contextualise the clinical picture—notably pain response, hypothermia, and fluid character—to guide referral and surgical decision-making, whilst recognising that the predictive model may shift depending on the suspected location of obstruction.
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Practical Takeaways
- •Do not rely on peritoneal or blood lactate levels alone to diagnose strangulation; use them alongside clinical signs (pain severity, temperature) and fluid characteristics (appearance) for better diagnostic accuracy.
- •Serosanguineous peritoneal fluid is a strong indicator of strangulation (35× increased odds); combined with other variables, this improves early surgical decision-making.
- •The relationship between peritoneal and blood lactate is complex and varies by lesion location, so clinicians should consider the whole clinical picture rather than any single lactate-based threshold.
Key Findings
- •Multivariable models combining multiple admission variables predicted strangulating obstruction with AUC ROC of 0.91, substantially better than individual variables alone.
- •The final SO prediction model included marked abdominal pain (OR 5.31), rectal temperature (OR 0.30), serosanguineous peritoneal fluid (OR 35.34), peritoneal-blood l-lactate difference (OR 1.77), and peritoneal:blood l-lactate ratio (OR 0.36).
- •For small intestinal strangulation specifically, reflux volume, blood l-lactate concentration, serosanguineous fluid, and peritoneal l-lactate concentration were most predictive.
- •Blood and peritoneal l-lactate concentrations should be interpreted together with other clinical variables rather than in isolation for predicting strangulation.