Concentrations of serum amyloid A and plasma fibrinogen in horses undergoing emergency abdominal surgery

Abstract

Objective: To compare the perioperative response of serum amyloid A (SAA) to fibrinogen in horses requiring exploratory celiotomy for colic and to determine if SAA could be used to predict complications and outcome.

Design: Prospective observational clinical study.

Setting: University teaching hospital.

Animals: Eighteen horses undergoing exploratory celiotomy for colic. Inclusion criteria for the study included survival and anesthetic recovery from exploratory celiotomy, no history of surgery within the past year.

Interventions: Blood was obtained via jugular venipuncture before surgery (time 0) and at 24, 48, 72, and 96 hours after recovery from anesthesia.

Measurements and main results: Quantitative and semiquantitative fibrinogen, SAA, total nucleated cell counts, and total protein were evaluated at each time point. Multivariable linear regression was used to assess differences at each time point and after grouping horses according to duration of colic prior to surgery, strangulating surgical lesion or not, presence of systemic inflammatory response syndrome (SIRS) on admission, and postsurgical complications. Significant (P < 0.05) increases in SAA concentrations occurred in all cases after surgery compared to fibrinogen concentration, which only demonstrated a mild, clinically insignificant increase postsurgery. SAA concentrations were also significantly increased (P < 0.05) in cases identified with SIRS prior to surgery and postoperatively at 48 (P = 0.05) and 72 hours (P = 0.02) in horses that developed complications.

Conclusions: Measurement of SAA is a more sensitive indicator of inflammation than fibrinogen in the perioperative period of horses requiring exploratory celiotomy for colic. Serial measurement of SAA at 48, 72, and 96 hours after surgery may be helpful to determine risk of complications and guide postoperative management. Measurement of SAA on admission also allows for quantification of SIRS when it is detected clinically.

Keywords: acute phase protein; colic; complications; horse; systemic inflammatory response syndrome.