Background: The predictive capabilities of peritoneal fluid lactate (PFL) to total solids ratio (PFL:PFTS) for detecting strangulating and non-strangulating lesions of the small intestine (SI) and large colon (LC) in horses is yet to be determined. Objective/hypothesis: Determine the discriminatory capabilities of PFL and PFL:PFTS and the peritoneal lactate to blood (PFL:BL) ratios to differentiate horses with small intestine (SI) and large colon (LC) strangulating (SO) and non-strangulating (NSO) obstructions.
Methods: Retrospective study. 282 horses, with 117 having SI lesions (59 classified as SINSO and 58 as SISO) and 165 with LC lesions, including 126 LCNSO and 39 LCSO. Receiver operating characteristic (ROC) curves were generated to identify optimal cut-off points, maximizing sensitivity (Sn) and specificity (Sp) for differentiating SO from NSO.
Results: A PFL concentration of 6.95 mmol/L and 7.15 mmol/L showed good and excellent discriminatory capabilities for identifying SISO and LCSO (AUC=0.824, 95 % CI = 0.750-0.898) Sn= 74 % and Sp= 80 % and AUC = 0.91, 95 % CI = 0.875-0.960; Sn = 83 % and Sp=88 %) respectively. A PFL:BL ratio of 1.28 and 1.54 showed fair and good discriminatory capabilities for identifying SISO and LCSO (AUC=0.67, 95 %CI=0.572-0.770, Sn= 87 % and Sp=47 % and AUC=0.81, 95 %CI=0.744-0.889), Sn= 72 % and Sp=75 %) respectively. A PFL:PFTS ratio of 2.9 and 3.6 showed fair and good discriminatory capabilities for identifying SISO and LCSO (AUC=0.76, 95 % CI=0.671-0.847, Sn= 67 % and Sp= 78 % and AUC= 0.84, 95 % CI = 0.781-0.907; Sn= 78 % and Sp= 81 %) respectively.
Conclusions: PFL:PFTS ratio can be used as screening tests to differentiate ischemic strangulating from non-strangulating lesions of the SI and LC.
