Wound Management: Wounds with Special Challenges.

Distal limb wounds in horses heal substantially different than trunk wounds, commonly resulting in exuberant granulation tissue and exposed and sequestered bone. Surgical intervention of severe rectovaginal lacerations in the mare should be delayed until the tissues have heeled and scar tissue has remodeled. Wounds resulting in severe hemorrhage require appropriate emergent fluid therapy and potentially transfusion therapy.

Equine Wound Management: Bandages, Casts, and External Support.

Successful management of equine wounds relies on knowledge of the stages of wound healing, factors that can alter those stages, how healing stages can be manipulated, and adherence to the principles of wound healing. Challenges that complicate wound management include the inability to immobilize and/or confine equine patients, and maintain a clean environment during the critical initial stages of healing. Because of these challenges, the equine practitioner relies heavily on bandaging and external coaptation techniques to successfully treat and manage wounds. The type of bandage used is dictated by the region of the body that is injured.

Perianesthetic development of diaphragmatic hernia in a horse with equine pituitary pars intermedia dysfunction (PPID).

A 21-year-old Thoroughbred gelding with a history of equine pituitary pars intermedia dysfunction (PPID) presented with priapism of 2 days' duration. The horse received a caudal morphine epidural and then underwent corpus cavernosum lavage and phallectomy under general anesthesia. The patient's recovery featured multiple unsuccessful attempts to stand and his respiratory distress persisted for several hours until he acutely developed severe colic and was euthanized. Necropsy findings revealed a pituitary adenoma of the pars intermedia, bilateral adrenal cortical hyperplasia, and diaphragmatic herniation. This report suggests that horses with PPID may present a greater risk for diaphragmatic hernia under general anesthesia or during procedures placing stress on the diaphragm, including anesthetic recovery.

Développement périanesthésique d'une hernie diaphragmatique chez un cheval atteint d'une dysfonction de l'hypophyse pituitaire (DHP). Un hongre Thoroughbred âgé de 21 ans avec une anamnèse de dysfonction de l'hypophyse pituitaire (DHP) a été présenté avec un priapisme présent depuis 2 jours. Le cheval a reçu une épidurale caudale de morphine et a ensuite subi un lavement du corps caverneux et une phallectomie sous anesthésie générale. Le rétablissement du patient a comporté de nombreuses tentatives infructueuses de se tenir debout et sa détresse respiratoire a persisté pendant plusieurs heures jusqu'à ce qu'il développe de graves coliques et soit euthanasié. Les constatations à la nécropsie ont révélé un adénome pituitaire de l'hypophyse, de l'hyperplasie corticale bilatérale et une herniation diaphragmatique. Ce rapport suggère que les chevaux atteints de DHP peuvent présenter un plus grand risque d'hernie diaphragmatique sous anesthésie générale ou durant des interventions exerçant un stress sur le diaphragme, y compris le réveil après l'anesthésie.(Traduit par Isabelle Vallières).

Effects of approach and injection volume on diffusion of mepivacaine hydrochloride during local analgesia of the deep branch of the lateral plantar nerve in horses.

OBJECTIVE: To compare the effects of 2 approaches and 2 injection volumes on diffusion of mepivacaine hydrochloride for local analgesia of the deep branch of the lateral plantar nerve (DBLPN) in horses. DESIGN: Experimental study. ANIMALS: 16 adult horses. PROCEDURES: Either 2 mL (low volume) or 8 mL (high volume) of mepivacaine hydrochloride-iohexol (50:50 mixture) was injected by means of 1 of 2 techniques to produce analgesia of the DBLPN. For technique 1, the needle was inserted 15 mm distal to the head of the fourth metatarsal bone and directed perpendicular to the limb. For technique 2, the needle was inserted 20 mm distal to the head of the fourth metatarsal bone and was directed in a proximodorsal direction. Lateromedial radiographs were obtained before and 5, 15, 30, and 60 minutes after injection. Radiographs were evaluated to determine the proximal and distal extent of diffusion of the contrast solution and presumably anesthetic agent and whether contrast agent appeared to be present in the tarsal sheath or tarsometatarsal joint. RESULTS: A high degree of variability in contrast solution diffusion was noted among injections. High-volume injections diffused significantly further proximally and distally than did low-volume injections. Contrast agent was documented within the tarsal sheath in 5 of 32 (16%) injections and within the tarsometatarsal joint in 2 of 32 (6%) injections. No significant difference was found for risk of inadvertent tarsal sheath or tarsometatarsal joint injection between the 2 techniques or the 2 volumes of anesthetic used. Mepivacaine diffused significantly further distally with technique 1 than with technique 2 but diffused significantly further proximally with technique 2 than with technique 1. For both techniques, diffusion in the distal but not the proximal direction significantly increased over time. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the proximal and distal diffusion of the mepivacaine-iohexol solution was quite variable following either DBLPN nerve block technique.

Equine imaging: the framework for applying therapeutic farriery.

Radiographic evaluation of a horse's foot gives tremendous insight into the relationship between the structures within the foot and between the foot and distal limb. The information gained from a radiographic study is highly dependent on the quality of the radiographs. A systematic approach should be taken when planning a radiographic study of the foot. Taking the time to examine the foot and prepare it properly will avoid the need, risk, and expense of repeating images and will improve the quality and therefore the interpretation of your radiographic images. When evaluating the foot for podiatry reasons, it is crucial that the positioning of the patient, foot, and x-ray beam be flawless.

Effects of changing body position on oxygenation and arterial blood pressures in foals anesthetized with guaifenesin, ketamine, and xylazine.

OBJECTIVE: To investigate the impact of a change in body position on blood gases and arterial blood pressures in foals anesthetized with guaifenesin, ketamine, and xylazine. STUDY DESIGN: Prospective, randomized experimental study. ANIMALS: Twelve Quarter Horse foals, age of 5.4 +/-0.9 months and weighing 222 +/- 48 kg. METHODS: Foals were anesthetized with guaifenesin, ketamine, and xylazine for 40 minutes in lateral recumbency and then assigned to a change in lateral recumbency after hoisting (Group 1, n = 6), or no change (Group 2, n = 6). Oxygen 15 L minute(-1) was insufflated into the endotracheal tube throughout anesthesia. Arterial blood pressure, heart rate, respiratory rate (f(R)), inspired fraction of oxygen (FIO(2)), and end-tidal carbon dioxide (PE'CO(2)) were measured every 5 minutes. Arterial pH and blood gases [arterial partial pressure of oxygen (PaO(2)), arterial partial pressure of carbon dioxide (PaCO(2))] were measured at 10, 30, and 40 minutes after induction, and 5 minutes after hoisting. Alveolar dead space ventilation and PaO(2)/FIO(2) were calculated. Two repeated measures models were used. All hypothesis tests were two-sided and significance level was alpha = 0.05. All values are presented as least square means +/- SE. RESULTS: Values at time-matched points from the two groups were not significantly different so they were combined. Arterial partial pressure of oxygen decreased significantly from 149 +/- 14.4 mmHg before hoisting to 92 +/- 11.6 mmHg after hoisting (p = 0.0013). The PaO(2)/FIO(2) ratio decreased from 275 +/- 30 to 175 +/- 24 (p = 0.0055). End-tidal carbon dioxide decreased significantly from 48.7 +/- 1.6 to 44.5 +/- 1.2 mmHg (p = 0.021). Arterial partial pressure of carbon dioxide, blood pressures and heart rates measured 5 minutes after hoisting were not different from measurements obtained before hoisting. CONCLUSION AND CLINICAL RELEVANCE: Hoisting decreased PaO(2) in anesthetized healthy foals. Administration of supplemental oxygen is recommended to counter the decrease in oxygenation and PaO(2) measurement is necessary to detect early changes.

Effect of carboxymethylcellulose and hyaluronate solutions on jejunal healing in horses.

OBJECTIVE: To compare a double-layer inverting anastomosis with a single-layer appositional anastomosis, coated with either 1% sodium carboxymethylcellulose (SCMC) or 0.4% sodium hyaluronate (HA) solutions, in the small intestine of horses with respect to anastomotic healing and adhesion formation. ANIMALS: 18 adult horses. PROCEDURE: Midline celiotomy and end-to-end jejunal anastomoses were performed. In control group horses (n = 6), a double-layer inverting anastomosis coated with sterile lactated Ringer's solution was performed. In treatment group horses, a single-layer appositional anastomosis was performed that was coated with 1% carboxymethylcellulose solution (SAA + SCMC group horses, 6) or 0.4% hyaluronate solution (SAA + HA group horses, 6). An additional 500 mL of the respective treatment solution was applied to the jejunal serosal surface, and 2 jejunal serosal abrasion sites were created. Horses were euthanatized 10 days after surgery. Anastomoses and abdominal adhesions were evaluated grossly. Anastomotic healing was evaluated on the basis of bursting wall tension. RESULTS: Bursting wall tension was significantly greater in SAA + SCMC group horses, compared with control group horses. All intestinal segments failed at a point distant to the anastomosis. Significantly fewer adhesions were found at the abrasion sites of SAA + HA group horses, compared with control group horses. No differences were found in adhesion formation at the anastomotic sites among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Coating a single-layer appositional jejunal anastomosis with SCMC or HA solutions does not adversely affect anastomotic healing. Application of 0.4% HA solution to the serosal surface of the jejunum significantly decreases the incidence of experimentally induced intra-abdominal adhesion formation in horses.