The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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24 TheHorse.com THE HORSE December 2017 Types of small intestine disease include: ■ SO These are always surgical cases. "It's not going to fix itself medically on the farm," Williams said. "The lesion has dictated what the horse needs." ■ Inflammatory disease (e.g., enteritis) While these aren't usually surgical, they do require a lot of time and effort spent refluxing (emptying stomach contents via stomach tube) and getting fluids into the horse. Thus, Williams recom- mends referral, if practical. ■ NSO Veterinarians can manage these horses on the farm with sedation, gastric decompression, and intrave- nous (IV) fluids. While it's less common for these cases to become surgical, Williams said veterinarians might elect to refer if it looks like there will be frequent farm visits. Types of large intestine disease include: ■ SO Again, SOs such as volvulus (twists) aren't going to fix themselves. Refer, said Williams. ■ Inflammatory disease (e.g., hypovole- mic shock) These cases almost always require referral so the horse can be isolated to prevent spread of pathogens such as Salmonella. These horses also require continuous support, including IV fluids and cryotherapy or icing to prevent secondary laminitis. ■ NSO "These are the vast majority of col- ics we see," said Williams, and they in- clude impactions, left and right dorsal displacement, and gas/spasmodic colic. He said veterinarians can manage them in the field with sedation, supportive fluids, and hand-walking. If horses don't respond to treatment, however, they might still be referred. Generally, horses with mild to moderate pain that are medically manageable can be treated in the field, said Williams. Sce- narios in which the veterinarian should refer the horse immediately include: ■ Distended loops of small intestine, evi- dent via rectal exam or ultrasound; ■ Postpartum broodmares; ■ Diarrhea, for biosecurity reasons; ■ Cardiovascular instability; ■ A very, very painful horse; and ■ Uncertainty about lesion site or type. Once the horse arrives at the hospi- tal, the referral vet will repeat the colic workup, possibly take bloodwork, analyze abdominal fluids, and make a recommen- dation about whether to go to surgery. Williams wrapped up his presentation with practical tips for deciding how to manage a colicking horse: ■ Be sure of the lesion site and type. ■ Make sure the owner knows the costs. ■ Estimate how much multiple farm visits or treatment at the primary clinic will cost. Sometimes it's more cost- effective and efficient to refer. ■ Make sure the owner knows that delaying surgery after it's been recom- mended might increase the risk of postoperative complications. "Eighty to 90 percent of presenting colics (at the University of Georgia's Veterinary Medical Center) don't go to surgery," said Williams. "For many cases, referral is more about the ability to man- age efficiently. "If you're not sure what's going on," he added, "don't sit on it." Study Supports Stent Use After Colic Surgery More horses are surviving colic surgery than ever. But with that trend inevitably come more postoperative complications, including incisional infections. These infections are a significant cause of illness—not to mention expense—after colic surgery, so University of California, Davis, (UC Davis) researchers recently tested how well different stent bandages prevent them, namely one made with an antimicrobial-impregnated dressing. "It's been suggested that environmental contamination of the incision either dur- ing or following recovery from anesthesia can play a major role in development of surgical site infection," said Isabelle Kilcoyne, MVB, Dipl. ACVS, an equine surgeon at the UC Davis School of Veteri- nary Medicine. She has assessed ways to reduce incisional infection risk in several studies and noted that risk factors range from having an incision longer than 27 centimeters to postoperative pain that causes horses to lie down more often. Kilcoyne's team had already deter- mined that covering incisions with an abdominal bandage during anesthe- sia recovery helps prevent incisional infections. Further, they knew a stent bandage— essentially, a rolled-up sterile towel sutured to the incision site imme- diately after surgery—reduced the risk of incisional complications. But they hadn't yet compared sterile towel stents to a simple adhesive drape cover and wanted to evaluate use of a stent bandage im- pregnated with 0.2% polyhexamethylene biguanide (PHMB), which, basically, kills bacterial cells by draining them. Kilcoyne said manufacturer studies in humans and independent studies in small animals showed that PHMB-impregnated dressing reduced antibiotic-resistant bac- teria within the bandage and colonization on the skin beneath it. She and her research team compared the stents and the adhesive drape in a group of 75 horses undergoing ventral midline exploratory celiotomy (colic sur- gery). Surgeons used a standard abdomi- nal closure protocol on all the horses. Following closure of the incision they COLIC: An Ever-Evolving Issue For many cases, referral is more about the ability to manage efficiently." DR. JARRED WILLIAMS Researchers compared the risk of incision infection using (from left to right) a sterile towel stent, a PHMB-impregnated stent, and an adhesive drape cover. COURTESY DR. ISABELLE KILCOYNE