Use of ultrasound to evaluate outcome following colic surgery for equine large colon volvulus.

REASONS FOR PERFORMING STUDY

The post operative response of the large colon wall after a surgically corrected large colon volvulus (LCV) has not been investigated.

OBJECTIVES

To use transabdominal ultrasound to monitor the post operative change in large colon wall thickness following surgical correction of LCV.

HYPOTHESIS

A prolonged period to colon wall involution is correlated with an increased rate of post operative morbidity and mortality.

METHODS

A prospective clinical study including horses that presented to the North Carolina State University Veterinary Teaching Hospital for colic between September 2006 and March, 2008, had surgically diagnosed and corrected LCV (at least 360 degrees ) without resection and recovered from anaesthesia. Ultrasound of the ventral large colon was performed at the time of anaesthetic recovery and every 6-8 h until the colon wall returned to normal thickness (< or = 5 mm). Outcome was evaluated using a one-way ANOVA to compare average time to colon wall involution between: 1) survivors and nonsurvivors; and 2) horses that developed multiple organ dysfunction syndrome (MODS) during the post operative period and those that recovered without evidence of MODS.

RESULTS

Sixteen horses that recovered without evidence of MODS had a significantly shorter period to colon wall involution (< or = 5 mm) compared to those diagnosed with MODS (mean +/- s.e. 19.6 h +/- 2.5 and 39.7 h +/- 6.7 respectively, P = 0.006). There was no significant difference in mean period to colon wall involution between survivors and nonsurvivors (26.2 +/- 4.9 and 33.2 +/- 7.8 h, respectively).

CONCLUSIONS

A shorter time to colon wall involution was associated with decreased post operative morbidity in horses presented for surgical correction of large colon volvulus without resection.

POTENTIAL RELEVANCE

Ultrasonographic monitoring of colon wall involution after surgical correction of LCV may aid in identifying those cases at risk of MODS. Further investigation of colon wall involution time using a larger number of horses is warranted.