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.
Issue link: https://thehorse.epubxp.com/i/899161
28 TheHorse.com THE HORSE December 2017 A measured in the blood performed the best of the acute phase proteins. Measur- ing SAA in serum can improve the ability to predict prognosis in horses with acute colic as survivors or nonsurvivors." Risk Factors for Colic Surgery Incision Failure Studied While colic surgery is a life-saving procedure for many horses, it's not without its risks. One rare, but potentially catastrophic, complication that occurs in 1% of colic surgery patients is abdominal incision dehiscence and visceral prolapse—when the incision the surgeon made in the abdomen reopens, allowing the intestines to drop out. In the best-case scenario the surgeon can clean up and resuture the incision without additional complications. In the worst-case scenario intestinal damage and abdominal contamination occurs and the horse must be euthanized. Alison Gardner, DVM, MS, Dipl. ACVS- LA, an assistant professor at The Ohio State University College of Veterinary Medicine, and colleague Margaret Mudge, VMD, Dipl. ACVS, ACVECC, a clinical associate professor, recently reviewed 10 years of medical records to identify risk factors for acute ventral midline dehis- cence and evaluate survival after wire placement to re-close the incision. The team evaluated 10 cases with acute dehiscence and visceral protrusion, half of which were draft horses. Horses' weights ranged from 227 to 900 kilograms (about 500 to 1,984 pounds), with an average of 540 kilograms (about 1,200 pounds). Key findings included: ■ Incision dehiscence, a previously iden- tified risk factor, occurred, on average, eight days after surgery; ■ Seven horses had signs of incisional infection prior to dehiscence, two of which survived; ■ Eight horses dehisced while still at the clinic; the two horses that dehisced fol- lowing discharge did not survive; ■ Four of the 10 cases dehisced after a second colic surgery; ■ Two horses developed hemoabdomen (blood accumulation in the abdomen) following difficult recoveries; ■ All cases had abdominal wall failure with the suture line remaining intact, meaning the abdominal wall itself tore, rather than the sutures reopening; and ■ Surgeons re-closed the abdominal wall in three horses using 18-gauge wires, and two of the three survived. Gardner and Mudge deduced that drafts and other horses with incisional infections could be more likely to suffer body wall failure and incisional dehis- cence and hemoabdomen, and hypopro- teinemia (decreased blood protein levels) at surgery could be a precursor to abdom- inal wall failure and subsequent dehis- cence. Gardner cautioned that research- ers still need to evaluate these factors statistically against controls. Further, they determined that horses are more likely to survive if incisional failure is identified promptly and treated immediately. While the team garnered important information on body wall failure and incisional dehiscence, Gardner stressed that this complication is rare. "I don't want owners to decline sur- gery because they're worried about this complication," she said. "The purpose of the case series was to correlate clinical signs that these horses may have prior to dehiscence. Ongoing work with cases from other hospitals is occurring, along with case controls for statistical analysis of risk factors." Equine Gut Microbiota Update By now you've probably heard about the diverse microbial communities that inhabit your horse's GI tract—collectively called the gut microbiota. Researchers know these tiny microorganisms have a major impact on horse health, and dis- rupting them can result in life- threatening conditions such as colic, colitis, antibi- otic-associated diarrhea, and laminitis. Essentially, a healthy or unhealthy micro- biome could mean the difference between life and death for your horse. Scientists have only been studying the microbiota since the early 2000s and are COLIC: An Ever-Evolving Issue Inflammatory Markers Could Help Vets Catch Colic Surgery Complications Complications following colic surgerycan put a horse back into a precarious, even life- threatening position. Treating complications early can help improve outcomes, but it's not always easy to tell which horses are most at risk for developing problems. Michael De Cozar, BSc(Hons), BVetMed, MRCVS, shared the results of a study in which he and colleagues evaluated whether two biomarkers in horses' blood—serum amyloid A (SAA) and plasma fibrinogen concentrations—could help predict colic surgery complica- tions. De Cozar is a surgery resident at Bell Equine Veterinary Clinic, in Kent, England. Serum amyloid A is a protein produced in response to an inflammatory insult. Im- portantly for veterinarians, its concentrations increase and decrease rapidly, giving them real-time information on inflammation via a blood test. Fibrinogen is also an inflammatory marker, but it doesn't change quite as quickly as SAA. In their prospective study, the researchers measured SAA and fibrinogen concentrations in horses undergoing exploratory laparotomy or celiotomy (abdominal surgery) at admis- sion and again every 24 hours for five days following surgery. Their study population included 275 horses—165 geldings, 102 mares, and eight stallions—ranging in age from 2 to 31. Fewer than half the horses (125/275, 45.5%) developed postoperative complications. De Cozar said SAA concentrations peaked on Days 3 and 4 following surgery in horses without and with complications, respectively. Additionally, in horses that developed compli- cations, SAA concentrations were significantly higher on Days 2, 3, 4, and 5. Meanwhile, fibrinogen concentrations peaked on Day 4 in horses without complications, but continued to increase on Day 5 in horses that developed complications. Also on Day 5, fibrinogen concentrations were significantly higher in horses with complications. De Cozar said these results suggest that horses' acute inflammatory responses are prolonged following colic surgery and peak three to four days after celiotomy. So, if inflammatory markers continue to increase post-Days 3-4, veterinarians might suspect an underlying complication. "The use of inflammatory markers may be helpful to detect postoperative complica- tions," he said. "Further studies are warranted to explore these associations." Still, De Cozar said veterinarians can begin monitoring SAA and fibrinogen levels fol- lowing surgery, "especially monitoring SAA trends over the first few days after exploratory laparotomy to catch possible complications early."