Immediate surgical intervention for small animal pyometra shows no definitive advantage.

Objective: To describe preoperative parameters and outcomes in small animals undergoing ovariohysterectomy (OVH) for pyometra relative to duration of stabilization and surgical timing. Methods: This retrospective observational study included canine patients undergoing emergency OVH for pyometra. We searched electronic medical records to identify patients undergoing OVH for pyometra between November 2018 and July 2024 at 3 referral hospitals. Presentation, anesthetic induction, and discharge or mortality were recorded for 137 patients. Regression analyses were used to determine predictive impact of cervix patency, stabilization time, and after-hours procedures on surgery and anesthetic time, postoperative hospitalization, and cost. Results: We found no difference in surgical time, anesthetic time, or postoperative hospitalization across surgical timing groups. There was also no observed difference between open and closed pyometra for any of the evaluated variables. Total cost was modeled to be lower by 19% (β = -$1,058.9; adjusted R2 = 0.043; 95% CI, -$1,831.03 to -$286.77) when patients presented after hours and to increase with additional stabilization (β = $43.20/h; adjusted R2 = 0.042; 95% CI, $11.58 to $74.88). Conclusions: This study indicated that operating time does not meaningfully affect clinical outcomes for open and closed pyometra other than a predicted increase in total cost. Clinical Relevance: Immediate surgical intervention for patients with pyometra may not be superior to delayed surgical intervention.