When Conservative Therapy Fails: Emergency Surgical Management of Haemoperitoneum in Horses

Haemoperitoneum (HP) in horses can rapidly progress from a medically manageable condition to a life-threatening surgical emergency. This case involving a pregnant mare with bilateral granulosa cell tumours (GCTs) highlights the importance of recognising ongoing haemorrhage and making timely surgical decisions. 

Acute Clinical Deterioration 

Following initial stabilisation and discharge, the mare deteriorated dramatically within 24 hours. Clinical findings included¹: 

• Tachycardia (90 beats/min)  

• Pale mucous membranes  

• Prolonged capillary refill time  

• Reduced gut sounds  

• Progressive weakness  

Ultrasonography revealed a marked increase in free abdominal fluid compatible with haemorrhage, while rectal examination identified severe bilateral ovarian enlargement, with both ovaries measuring approximately 15–20 cm. 

Laboratory Indicators of Severe Haemorrhage 

Serial laboratory findings confirmed progressive cardiovascular compromise¹: 

• Packed cell volume (PCV) dropped from 24% to 11%  

• Total protein (TP) declined to 30 g/L  

• Blood lactate increased to 17.6 mmol/L  

• Severe hypoxaemia developed despite oxygen supplementation  

These findings indicated severe hypovolaemic shock and tissue hypoperfusion. 

Key Clinical Insight 

Progressive hypoproteinaemia and worsening tachycardia despite therapy strongly suggested ongoing intra-abdominal bleeding. 

Emergency Stabilisation 

Initial emergency therapy included: 

• Whole blood transfusion  

• Tranexamic acid  

• Hypertonic saline  

• Colloid support  

• Flunixin meglumine  

• Oxygen supplementation  

Tranexamic acid was administered to reduce fibrinolysis and stabilise clot formation, although clinical evidence regarding its efficacy in equine haemoperitoneum remains limited². 

Despite aggressive medical management, the mare continued to deteriorate, making surgical intervention essential. 

Why Surgery Became Necessary 

Medical management was considered unsuccessful because¹: 

• Tachycardia continued worsening  

• PCV and TP kept declining  

• Lactate levels rose progressively  

• Ongoing haemorrhage was suspected  

• Blood transfusions failed to stabilise the mare  

At this stage, surgical control of haemorrhage became the only realistic option for survival. 

Why Standing Surgery Was Chosen 

General anaesthesia was considered extremely high risk due to: 

• Severe hypovolaemia  

• Anaemia  

• Cardiovascular instability  

• Metabolic compromise  

Anaesthetic agents can significantly depress cardiovascular function in unstable horses and increase perioperative mortality risk¹. 

Advantages of Standing Surgery 

Standing laparoscopic-assisted surgery offered³: 

• Reduced cardiovascular depression  

• Lower anaesthetic risk  

• Faster surgical intervention  

• Improved haemodynamic stability  

Surgical Management 

A standing bilateral laparoscopic-assisted ovariectomy was performed. 

Perioperative Support Included: 

• Blood transfusions  

• Antimicrobials  

• Morphine analgesia  

• Ketamine constant rate infusion  

• Colloid therapy  

• Local infiltration with mepivacaine  

Severe haemoperitoneum significantly impaired laparoscopic visualisation. Therefore, a hand-assisted laparoscopic approach was used to: 

• Facilitate blood removal  

• Improve palpation  

• Enhance visualisation  

• Allow direct haemorrhage control  

Active bleeding was identified from both ovaries, and the ovarian pedicles were coagulated and transected using a vessel sealing device⁴. 

Postoperative Outcome 

Postoperatively, the mare received additional blood transfusions and plasma support. Clinical parameters improved rapidly, including: 

• Resolution of tachycardia  

• Stabilisation of PCV  

• Improved perfusion  

• Reduction in abdominal fluid accumulation  

Remarkably, the pregnancy remained viable and progressed successfully to term¹. 

Practical Clinical Takeaways 

This case highlights several important lessons for equine practitioners: 

• Persistent tachycardia may indicate ongoing haemorrhage  

• Serial lactate monitoring is valuable in assessing perfusion  

• Falling TP can precede severe PCV decline  

• Conservative therapy has limits in active bleeding cases  

• Standing laparoscopic surgery can be life-saving in unstable horses  

Conclusion 

This case demonstrates that progressive tachycardia, worsening lactate, declining TP, and increasing abdominal fluid accumulation should prompt urgent reassessment in horses with haemoperitoneum. 

It also highlights that standing laparoscopic-assisted surgery can provide a life-saving alternative to general anaesthesia in critically compromised equine patients. 

References  

1. Sinovich M, Archer DC, Kane‐Smyth J, Scarabelli S, Ritchie A, Kelly PG. Haemoperitoneum associated with bilateral granulosa cell tumours in a pregnant mare treated by standing ovariectomy. Equine Veterinary Education. 2022 Dec;34(12):e526-32. https://beva.onlinelibrary.wiley.com/doi/pdfdirect/10.1111/eve.13612  

2. Fletcher DJ, Brainard BM, Epstein K, Radcliffe R, Divers T. Therapeutic plasma concentrations of epsilon aminocaproic acid and tranexamic acid in horses. Journal of veterinary internal medicine. 2013 Nov;27(6):1589-95. https://doi.org/10.1111/jvim.12202  

3. Daniel AJ, Easley JT, Story MR, Hendrickson DA, Hackett ES. Standing hand‐assisted laparoscopic removal of large granulosa cell tumours in horses using a specimen retrieval bag and morcellator. Equine Veterinary Education. 2015 Oct;27(10):505-9. https://doi.org/10.1111/eve.12374  

4. Colbath AC, Hackett ES, Lesser CS, Hendrickson DA. Left paralumbar laparoscopic bilateral ovariectomy in mares. Veterinary Surgery. 2017 May;46(4):574-9. https://doi.org/10.1111/vsu.12637