Equine Abdominocentesis

Indications for performing this procedure:  Abdominocentesis should be preformed in horses with acute or recurrent episodes of colic, chronic weight loss, or chronic diarrhea. 


The Procedure:  The abdomen is surgically prepared at a point approximately 4 inches caudal of the xiphi-sternum.  A small bleb of local anesthesia may be introduced to make the procedure more comfortable in a distressed or painful horse.  Introduction of an 18 gauge 1.5 inch needle is made quickly along the linea alba.  Fluid is collected into a Na EDTA tube for evaluation.  In large or obese horses, it may be necessary to use a teat cannula or a spinal needle to penetrate the linea alba and collect fluid.  In these instances, a stab incision will aid perforation of the abdominal wall.  These methods are less favored due to the introduction of blood into the sample.


Blood Contamination:  Contamination is limited by the use of an 18 gauge needle and minimal redirection during collection.  Minimal contamination will appear as pinks swirls in an otherwise clear sample.  If the spleen is punctured, the PCV of the sample will be greater than that of peripheral blood.  Diapedesis from damaged or non-viable bowel will generally yield a PCV of 5%.


Analysis:  The sample should be assessed for color upon collection.  Laboratory analysis of the sample includes PCV, RBC count, total and differential nucleated cell count, and total protein.


Interpretation:

  Normal Abnormal Possible Disease Process
Color clear to yellow 1.  Red to brown
2.  Orange to green
3.  Green and turbid
4.  Yellow and turbid		 1.  Small Intestine Strangulation
2.  Bowel necrosis/rupture
3.  Enterocentesis
4.  Anterior enteritis
Total Cell Count < 7,500
(<peripheral count)		 1. 15,000-250,000
2.  <1,000
3.  <10,000
4.  >150,000		 1.  Abdominal Abscess
2.  Enterocentesis
3.  Anterior enteritis
4.  Bowel necrosis
Total Protein < 2.0 mg/dl 1. 5.0-6.5
2. <3.0
3.  variable		 1.  Bowel necrosis
2.  Bowel impaction
3.  Enterocentesis
Cytologic Appearance 40-80% neutrophils
20-50% mononuclear cells		 1.  Predominantly neutrophils, degenerative.
2.  Predominantly neutrophils, in good to fair condition.
3.  Few cells, many bacteria		 1.  Small intestine strangulation, rupture, bowel necrosis.
2.  Abdominal abscess, impaction, anterior enteritis.
3.  Enterocentesis.


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