Triage for colic patients

The term "triage" is not used frequently in veterinary medicine, but is an integral method of managing emergency cases in human hospitals. The term, first developed in times of war, literally referred to the prioritization and rapid implementation of the proper treatments for injured soldiers.

The degree of shock will dictate the need for referral, so even if pain can be controlled, a horse with a high heart rate, discolored gums, delayed capillary refill time, or any of the above will need to be treated with fluids.

In order to imagine this process, it is helpful to think about the way MASH units worked. After checking into human hospital emergency rooms, the first stop is the triage nurse. This key person determines whether the patient needs to have immediate medical attention or wait for further evaluation in the waiting room.

In veterinary medicine, a good application of the triaging process is management of colic in horses. Triaging requires the veterinarian to switch thought process from pursuing a precise diagnosis to determining if a horse needs to be referred for intensive care, including surgery. Interestingly, this is a process veterinarians have been working on for years, but we still have a long way to go to perfect the process when evaluating horses with colic.

Triaging and survival in horses with colic

In thinking about how to increase the survival rate of horses suffering from colic, most veterinarians likely focus on the latest operative and postoperative treatments, but the impact of changes in these areas is ultimately very small when considering the entire population of horses suffering from colic.

Table 1 Pain Management

In general, the time between examination and referral has by far the largest impact on survival. An excellent example is treatment of large colon volvulus. This form of colic has the highest mortality rate, frequently about 50 percent at referral hospitals with the most up-to-date intensive care because they simply receive the case too late in the course of disease.

On the other hand, in high-density equine communities, where the farm managers and referring veterinarians make very rapid decisions on referral and the hospitals are very close, the survival rate is well more than 80 percent in some studies. There are certain realities to factor into these differences, including geographical location, and the ability of owners to make a rapid decision on potentially expensive care.

Considerations prior to referral

How can veterinarians in practice make use of this information? First, it is vital to have farms that each practice attends regularly to prepare for emergencies. This means that a decision on whether an owner would pursue referral, given the expense and the horse in question, is made before each horse has an episode of colic. The optimal approach to financial emergency planning is to suggest insurance to owners, particularly those that commit to referral of their horses. All owners should be encouraged to seek mortality and major medical insurance policies. Alternative policies, such as surgical insurance or loss of use policies are far more complex and will not protect the owner when an immediate decision on full medical care is required.

Colic events

Someone who can make triage decisions always should be present on the farm so if an owner is unavailable, then they can be reached easily or can transfer the decision-making to the trainer or farm manager.

A truck and trailer always should be readily available and fully functional, and every horse must be completely trained to load rapidly. This will avoid searching for suitable transportation in the middle of the night. As far as the role of the veterinarian, the relationship with the owner and trainer is critical.

Administration of medications for colic either should be solely the responsibility of the veterinarian, or the veterinarian should be notified immediately if the owner or trainer is given the responsibility of initially medicating the horse. Veterinarians should be aware that the law in each state regulating veterinary practice is different, and laws might prohibit veterinarians from transferring this responsibility to owners. In addition, most owners are not aware of this fact. Essentially, owners are not veterinarians and must understand that the veterinarian is legally in charge of medical treatment.

The decision to refer a horse

The key point here is that horses with colic are not referred for certain colic surgery; they are referred for further evaluation of colic because the index of suspicion that additional intensive care might be needed is heightened on the part of the veterinarian. Some veterinarians are concerned that if they refer a horse with colic and it does not go to surgery, then they might have made a bad decision. On the contrary, this is optimal in that the horse will be present at the referral facility so immediate intensive procedures can be performed if needed. Referral facilities have the responsibility of working closely with veterinarians to reinforce this concept and to provide state-of-the-art treatment for all patients regardless of the medical condition of the horse. In other words, everyone, including the owner, should feel good about the experience.

A stomach tube will provide both diagnostic information (presence or absence of reflux) and critical emergency care, particularly where excessive fluid may lead to rupture of the stomach during shipping.

As far as evaluation of the horse itself, key factors to consider are pain, systemic status of the horse, and any examination finding that raises the veterinarians index of suspicion that the horse has something other than a simple colic. I recommend initial treatment of the horse for pain, preferably after taking a heart rate, followed by a physical examination that will provide information on the degree of shock, the presence of reflux and gut sounds, and rectal examination findings. A rectal examination should be performed at the discretion of the veterinarian depending upon the horse, facilities, farm staff and severity of the problem. Once it has been determined that a horse becomes painful following reasonable treatment for pain, it is immediately a candidate for referral. This may be apparent on the first visit, and certainly on the second visit, which could take the form of a repeat telephone conversation with the owner.

The degree of shock will dictate the need for referral, so even if pain can be controlled, a horse with a high heart rate, discolored gums, delayed capillary refill time, or any of the above will need to be treated with fluids. These are typically given intravenously, and a baseline level of 15-20L should be given. This, in turn, is usually optimally given in a hospital setting.

Less-common findings would be abnormal rectal examination findings in the absence of pain, which would increase the likelihood for the need for referral, depending upon the veterinarians assessment. A stomach tube will provide both diagnostic information (presence or absence of reflux) and critical emergency care, particularly where excessive fluid may lead to rupture of the stomach during shipping.

Conclusions

In order to increase survival of horses, rapid triage decisions (full history and examination within 40-60 minutes if possible) and referral is of tremendous benefit. In effect, veterinarians should be trying to select horses that might require surgery rather than those that definitely require surgery. Once the referral hospitals receive the cases, they can make the final decision on surgery, but they can also provide life-saving intensive care for medical patients. The limiting factors are finances, on the part of the owner, and our willingness as an industry to step up our efforts to triage horses as fast as possible.

Dr. Anthony Blikslager is associate professor of equine surgery at North Carolina State University. He has a doctorate in gastrointestinal physiology and is certified by the American College of Veterinary Surgery. He focuses on surgery and critical care of the equine colic patient, and he helps man a federally funded research laboratory (NIH and USDA) investigating mechanisms of intestinal mucosal injury and repair. He has written for more than 50 veterinary publications and has authored/edited several textbook chapters on colic and gastroenterology, such as Current Therapy in Equine Medicine, Equine Internal Medicine, Large Animal Internal Medicine and Equine Surgery.