馬の消化管病変に対する術後腹腔内液分析：乳酸と総タンパク質はGI病変に対する開腹術後1週間で高値のまま。新しい基準値が必要。

To describe characteristics of postoperative peritoneal fluid following exploratory laparotomy for naturally-occurring gastrointestinal lesions in horses.

Prospective, observational cohort study.

A total of 26 client-owned horses that underwent exploratory laparotomy for naturally-occurring gastrointestinal lesions.

Abdominocentesis was performed pre- or intraoperatively, and at three time points postoperatively (24, 72, and 168 h). Peritoneal lactate, total protein (TP), total nucleated cell count (TNCC), cytology, and systemic lactate were performed at each time point, if possible. To account for repeated measures, a linear mixed model analysis was performed for each dependent variable listed above.

Horses were divided into groups based on the gastrointestinal lesion diagnosed at surgery (14 strangulating and 12 non-strangulating). Peritoneal lactate (p < .001) and TP (p = .02) were significantly higher preoperatively in horses with strangulating compared to non-strangulating lesions, with no significant differences between lesion groups for any postoperative measurement. Peritoneal lactate and TP concentrations remained above normal for the entire postoperative study period in both groups. Systemic lactate returned to normal concentrations by 24 h postoperatively with both groups being significantly lower than preoperative concentrations (p = .02). Peritoneal TNCC concentrations increased in strangulating (p = .001) and non-strangulating (p < .001) horses at 24 h postoperatively compared to preoperatively.

Regardless of lesion, peritoneal fluid lactate and TP remained above normal at 1 week following exploratory laparotomy for naturally-occurring gastrointestinal lesions in horses.

Current reference values for preoperative fluid sample analyses should not be used in the postoperative period.