February 2022

In this VETgirl online veterinary continuing education blog, Dr. Kathryn M. Slaughter-Mehfoud, DVM, MPH, Equine Surgeon, reviews how to prepare the equine colic for referral. And in case you missed it previously, you can read WHEN to refer an equine colic patient HERE!

Preparing the Equine Colic for Referral

By Kathryn M. Slaughter-Mehfoud, DVM, MPH, Veterinary Surgeon based out of Louisville, Kentucky

The horse is flopping, sweating profusely, and its heart rate is over 60 beats/minute. You’ve already made the decision to refer the horse for further evaluation, treatment, and potential surgery. The owner is hooking up the horse trailer or is frantically trying to find a hauler. What are you going to do next? There are an abundance of critical therapies the equine practitioner can perform prior to referral. Performing these therapies can be the difference between whether or not the horse survives colic surgery.

First, hydration. For the standard 500 kg horse, bolus 2 liters of hypertonic saline. This immediately improves hydration by expanding the vascular volume through the redistribution of fluid from intracellular and interstitial spaces. This effect lasts approximately 45 minutes, which is an excellent jump start for the compromised patient. Most referral hospitals have guidelines to determine if the horse is a good anesthetic and surgical candidate. If the patient’s hydration status is poor, surgery will be delayed for adequate hydration. Administering 2 liters of hypertonic saline prior to the horse getting on the trailer can literally make the difference between immediate or delayed surgery, and the latter decreases the horse’s chance of survival.

Second, nasogastric intubation. I get it–we all have our favorite nasogastric tube which we cherish and talk about lovingly to our colleagues. Please, I beg you, leave the nasogastric tube in the horse for the trailer ride. Surgeons LOVE when the referring veterinarian has left the nasogastric tube in place for the trailer ride to the hospital. Not only does it save us time in passing the tube, but it also prevents the horse’s stomach from rupturing on the way to the hospital. Every surgeon I’ve worked with always ships the nasogastric tube back to the referring veterinarian, cleaned and sterilized. I promise you, your surgeon will thank you and we will ship your favorite tube back to you!

Third, intravenous catheter. If you have time, surgeons greatly appreciate IV catheter placement prior to referral. Please choose the largest bore catheter available. There have been many, many times the horse arrives down on the manure filled trailer, it’s raining, and pitch black outside. Placing an IV catheter on a flailing horse, in a dirty trailer, with no lighting is not anyone’s favorite pastime. IV catheter placement prior to referral saves time at the hospital and gets the patient on the surgical table faster, increasing its chance of survival.

Fourth, sedation. If the trailer ride to the referral hospital is 30 minutes or less, xylazine is likely appropriate. If the trailer ride is going to be longer than 30 minutes, please use a longer lasting alpha-2 agonist, such as detomidine, in combination with an opioid, such as butorphanol. For the 500 kg horse, I use 5 mg detomidine and 5 mg butorphanol IV to achieve adequate sedation and pain relief. If the horse is extremely painful and has a particularly long trailer ride, administering butorphanol IM is also beneficial. This sedation protocol provides the best chance for the horse to still be standing on arrival to the hospital.

Fifth, call the referral hospital about medications. There are certain medications, particularly antibiotics, each referral hospital prefers. Before administering antibiotics, please call the referral hospital and ask the veterinarian what they would like administered and their preferred dosage. Every veterinarian has different, valid opinions on medication administration and dosages. However, if the referral hospital is going to be taking over treatment, it is extremely courteous to go ahead and initiate their protocols. In addition to antibiotics, please ask what dosage of flunixin meglumine and n-butylscopolammonium bromide (Buscopan) they would like administered prior to referral.

Performing these procedures and therapies prior to transport significantly increases the horse’s chance of survival. Saving the surgical colic horse’s life is a team effort between the referring veterinarian and the surgeon. Preparing the equine colic for referral is a critical step in the overall success of the patient; your patient and referral hospital thank you for your diligence!

  1. “Placing an IV catheter on a flailing horse, in a dirty trailer, with no lighting is not anyone’s favorite pastime” For certain, and it is even worse when the trailer is upside down in a deep ditch on a rainy night !!!

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