Wounds, Leg Trauma, and Respiratory Problems--Health Care Inside and Out

Discussions of products to treat wounds, leg trauma, and respiratory problems.

If you've been a horse owner for any length of time, there's a pretty good chance you've amassed an arsenal of products that claim some pretty spectacular results. While many might have delivered the goods, unless the fundamentals of a problem have been addressed, you very well could be wasting your money, or, worse, doing more harm than good.

However, by integrating new technologies with traditional methods, the results could prove to be quite successful, according to Grant Myhre, BS, DVM, RSO, whose cutting-edge Myhre Equine Clinic in Rochester, N.H., has seen a renaissance in equine health care practices.

Wound Care

Myhre says it is necessary to first identify what type of wound the horse has sustained. He describes, "Partial thickness wounds, for instance, are caused by a sharp or jagged object that does not penetrate through all layers of the skin; the cut edges stay close together and the bleeding is usually easy to control. Conversely, full-thickness wounds are a result of an object cutting through all layers of the skin and potentially penetrating the deeper underlying tissue. In these cases, the skin edges will often gape open and bleeding is quite substantial.

"As for puncture wounds," he notes, "they are commonly caused by a stake or nail and generally do not create much blood flow unless a major blood vessel is punctured."

Myhre says no matter what the situation might be, the skin begins a self-healing process within five minutes of the occurrence--white blood cells move in to kill bacteria and remove debris, fibrinogen is secreted by surrounding blood vessels to form a protective scab, and epidermal (skin) cells migrate across the wound, providing a fibrous tissue base over which new skin will form.

The primary concern is to debride the wound so that the healing process is not impeded by contamination," he emphasizes. "With the advent of handheld hydrotherapy devices (for veterinarian use) that utilize a high-velocity stream of sterile saline that 'cuts' into the targeted area (the Versajet Hydrotherapy System by Smith & Newphew, http://wound.smith-nephew.com/uk/node.asp?NodeId=3089, for example), they are able to remove debris from the site far more efficiently than conventional procedures allowed us to do in the past."

He says depending on the position and power level of the saline "wand," the veterinarian can control the cutting and irrigation effects. "For instance, at the lower levels it acts mainly as a vacuum to eliminate debris while minimizing tissue loss, but as the power is increased, it enables us to remove contaminated and damaged tissues, with the highest level cutting through for maximum debriding."

Myhre says for the horse that suffers from a musculoskeletal injury or undergoes surgery, proximate cells (skin cells surrounding the injury or surgical site) sustain trauma as well."

The "primary traumatic damage," which is the body's immediate response to acute stress by rushing blood to the site in an effort to begin regeneration, can result in a formation of a hematoma (an abnormal localized collection of usually clotted blood). This is associated with pressure, pain, and nerve damage.

Injury recovery is also complicated by "secondary hypoxic injury," which means impaired blood flow robs the area of oxygen, thus damaging more cells and leading to additional swelling that ultimately delays recovery time.

Reducing swelling, relieving pain, and minimizing cell and tissue damage is as simple as RICE (rest, ice, compression, and elevation), says Myhre. He says when administered correctly, these procedures can do much to address the previously cited problems.

Myhre declares cold therapy to be a staple in wound management. He says cold acts as a local anesthetic to control pain and quiet muscle spasms and lowers the metabolic rate of the injured and healthy cells, thereby decreasing oxygen demand to avoid secondary hypoxic injury. Cold in combination with compression therapy is recognized as a highly efficient method of wound treatment. "But the difficulty traditionally has been to get the area cold enough and to maintain a constant level of compression, especially when treating a leg wound," he says. "For instance, it has been the custom on racetracks to use ice boots that horses stand in for upwards of 30 minutes, but they're cumbersome at best and don't provide adequate compression."

These challenges have led to the introduction of leg wrap systems that utilize cold and compression therapy (for example, Game Ready Equine, http://www.gamereadyequine.com, kits starting at $3,200; some veterinarians rent these systems to their clients). "They are far more effective and easy to use" than just standing the horse in a tub of ice, states Myhre.

"Even though it's important to palpate the legs before and after exercise, tissue stress can easily occur, even with proper training, and many of these stresses are not easy to detect,' he says, promoting preventive use of cold compression therapy. "That's why it's beneficial to apply cold and compression on a routine basis."

Respiratory Health

A horse experiencing respiratory problems--just like any other athlete--isn't able to perform at his best. Myhre says the occurrence of nasal tissue collapse during exercise is common to all horses, and that collapse reduces the size of the airway, which forces a horse to work harder in order to breathe. "It's the upper airway, which comprises the nostrils, nasal passages, and the larynx, that is the point at which nasal resistance occurs," he explains. "That results in increased negative pressure when inhaling, followed by increased resistance within the lungs." Exercise-induced pulmonary hemorrhage (EIPH) can result.

Myhre calls attention to adhesive nasal strips as a drug-free, noninvasive way to support the external wall of the nasal passages (Flair Strips, around $8.50 each, see www.flairstrips.com for distributors). These are designed to prevent collapse or narrowing of the upper airway at the nasoincisive notch (the narrowest point located three to four inches above the nostrils) by holding open the nasal passages. By wearing the strips during exercise, the improved airflow has been shown to help horses maintain better overall respiratory health, with reduced EIPH and fatigue. He warns that nasal strips will not benefit every horse, but the cost to potentially improve his performance is minimal and, therefore, worth the investment.

Ken Hinchcliff, BVSc, MS, PhD, Dipl. ACVIM, dean of the Faculty of Veterinary Science at the University of Melbourne, and a noted respiratory researcher, says the bulk of the advances in respiratory health have been "in protection against respiratory disease through development of effective vaccines, notably Flu Avert (Intervet)--the intranasal vaccine--and Proteqflu (Merial, an influenza vaccine used in the United Kingdom and in the recent Australian equine influenza epidemic), and also the use of inhaled medications for inflammatory airway disease. The current vaccines are much more effective than ones available 10 years ago and, almost as importantly, are demonstrated to be effective.

"The use of inhaled medications for horses with inflammatory airway disease (heaves) has been a major breakthrough," Hinchcliff adds.

Another recent development has given veterinarians the ability to test horses for airway hyperreactivity and, thus, diagnose inflammatory airway disease. The system, called Open Pleth, is a portable open plethysmography system for horses that measures airflow at the opening of the nares in the horse, while also measuring volume displacements at the body surface using elastic sensors. The Equine Flowmetrics software that the system uses compares the flow at the nares and the chest/abdomen of the horse, and it records their differences as a signal proportional to constriction of airways (systems cost around $14,000, www.ambulatory-monitoring.com/open_pleth.html) .

Take-Home Message

In conclusion, it's safe to say that as our science becomes more sophisticated, we're able to solve many health problems that once left the community relying on outdated practices or even folklore as cures. With today's aggressive approach toward finding efficient and affordable products designed to optimize health and performance, horses are able to experience longer, better-quality lives.

By Toby Raymond and Stephanie L. Church

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