Chlorhexidine Diacetate and Povidone-iodine Cytotoxicity to Canine Embryonic Fibroblasts and Staphylococcus aureus

Chlorhexidine diacetate and povidone-iodine were evaluated for fibroblast toxicity on a primary line of canine embryonic fibroblasts, and for bactericidal efficacy against Staphylococcus aureus. The cultured fibroblasts or S. aureus were exposed for 30 minutes to incremental dilutions of 0.5 and 0.0005% chlorhexidine diacetate, 5.0 to 0.05% povidone-iodine, or physiologic buffered saline as a control. To determine survival, fibroblasts were trypsinized and counted; S. aureus colonies were counted on brain-heart infusion agar. Survival for both groups was expressed by calculating the number of living cells in test dilutions as a percentage of the number in control cultures. Fibroblast survival occurred at chlorhexidine concentrations less than 0.013% and at povidone-iodine concentrations less than 0.5% (p less than 0.05). Significant S. aureus survival (p less than 0.05) was noted at chlorhexidine concentrations less than 0.05% and povidone-iodine concentrations less than 1.0%. These data showed that all bactericidal concentrations of chlorhexidine diacetate and povidone-iodine were lethal to canine embryonic fibroblasts in vitro, whereas non-lethal concentrations allowed significant bacterial survival.     

Crosspin Fixation of Fractures of the Proximal Tibia in Three Foals

Three foals, each less than 1 month of age, were presented with Salter Type II fractures of the proximal tibial physis. Reduction of the fractures was accomplished manually and maintained by crosspin fixation. Fracture healing in two of the foals was uncomplicated. The third foal developed an infection around the implants, which responded to periodic local antiseptic flushing and administration of penicillin and gentamicin. Follow-up information ranging from 11 to 22 months after surgery revealed satisfactory results in two of three foals; premature closure of the proximal tibial physis was found in the other foal, resulting in the development of an angular limb deformity.     

Total Ear Canal Ablation Combined with Lateral Bulla Osteotomy for End-Stage Otitis in Dogs Results in Thirty Dogs

Thirty dogs with end-stage otitis were treated by either unilateral or bilateral total ear canal ablation and lateral bulla osteotomy. Otitis was considered end stage when the horizontal ear canal was collapsed, stenotic, or occluded in conjunction with chronic infection of the external and middle ear. The dogs were evaluated clinically and radiographically for 4 to 63 months. The frequency of scratching, head shaking, aural drainage, and para-aural fistulation was significantly decreased. Abnormal ear carriage and head tilt were not changed. The results in 23 dogs were graded as excellent or improved. One dog died of intraoperative hemorrhage. Complications during the period from suture removal to follow-up included para-aural fistulation (3 dogs), facial nerve paralysis (5 dogs), and head tilt (3 dogs).     

Accuracy of Arthroscopic Identification of Equine Carpal Lesions

The equine carpal joint was used to evaluate arthroscopic diagnosis of lesions created in joints obtained from horses euthanized for reasons other than lameness. Full-thickness articular defects were made in 13 sites within the antebrachiocarpal joint and middle carpal joint approximating those found in diseased carpal joints. Arthroscopic evaluation of the lesions included location, depth, and size of the defects. The joints were subsequently examined grossly. Results showed that, when compared to gross evaluation, arthroscopy is capable of accurately identifying subtle changes in articular cartilage and bone. A statistically significant increase in error rate was found for lesions at the medial aspect of the proximal radial carpal bone. Other sites with limited arthroscopic access were the proximal ulnar carpal bone, the proximal fourth carpal bone, and the distal intermediate carpal bone. The accuracy of arthroscopic identification of lesions improved significantly during the study as experience with the technique was gained.     

Hiatal Hernia Repair by Restoration and Stabilization of Normal Anatomy An Evaluation in Four Dogs and One Cat

Clinical signs of esophageal hiatal hernia in four dogs and one cat included regurgitation, vomiting, hematemesis, hypersalivation, dysphagia, and dyspnea. Thoracic radiographs, esophagram, and fluoroscopy were used to demonstrate cranial displacement of the esophagogastric junction and part of the stomach through the esophageal hiatus. Other findings included megaesophagus, esophageal hypomotility, gastroesophageal reflux, and pneumonia. Medical therapy failed to resolve the clinical signs. Reduction in size of the esophageal hiatus, fixation of the esophagus to the diaphragmatic crus (esophagopexy), and a left fundic gastropexy were performed. Surgical results were considered good to excellent.     

Introduction to the Quantitative Technique of Closed Circuit Anesthesia in Dogs

In humans, anesthetic uptake in a closed system with constant arterial concentration has been shown to be inversely proportional to the square root of time. A practical method for quantitative dosage of volatile anesthetic was derived from this. The method was evaluated in nine dogs anesthetized with a closed circle system using halothane and isoflurane. A unit dose (UD) of anesthetic was calculated in milliliters of vapor which was converted to milliliters of liquid and repeatedly administered into the expiratory limb between the squares of integer units of time (0-1, 1-4, 4-9 minutes, etc). The UD was derived as follows: UD = 2 f MAC X lambda B/G X 2 (kg)3/4, where f MAC was the desired alveolar concentration, lambda B/G the blood-gas partition coefficient, and 2 (kg)3/4 was an approximation of cardiac output. The method resulted in a stable plane of anesthesia and permitted continuous monitoring of O2 consumption. There was no significant difference between predicted and measured values of O2 consumption, cumulative doses, or alveolar concentrations at 9 and 16 minutes of anesthesia.     

Transdiaphragmatic Approach to Thoracic Duct Ligation in the Cat

An approach combining ventral midline celiotomy with transdiaphragmatic thoracotomy was evaluated in eight healthy cats for ligation of the thoracic duct system. Evans Blue solution was injected into the right colic lymph node to outline the intestinal lymphatic trunk and the thoracic duct system. Three cats (group 1) had mesenteric lymphangiograms and three (group 2) had only lymph node dye injection before thoracic duct ligation. The thoracic duct system was ligated with hemostatic clips just cranial to the aortic hiatus of the diaphragm, through a left transdiaphragmatic thoracotomy. Two cats (group 3) had prethoracotomy mesenteric lymphangiograms and thoracic duct isolation without ligation. Mesenteric lymphangiography was performed immediately after the surgery. In all of the cats, an absence of contrast medium in the thoracic duct system cranial to the surgical site was interpreted as complete obstruction. Four weeks after ligation, there was complete obstruction of the thoracic duct system with alternate lymphaticovenous communications in four of the six cats with ligated thoracic duct systems. Partial obstruction of the thoracic duct system with alternate lymphaticovenous communications was present in the other two cats. Both cats without thoracic duct ligation had patent thoracic duct systems. At necropsy of the six cats with ligated thoracic ducts, there was mild focal lymphadenitis of injected lymph nodes in three cats. The wall of the aorta adjacent to the hemostatic clips was normal in all six cats. The surgical technique was simple and provided excellent exposure. Vital staining with Evans Blue helped visualize the thoracic duct system, but mesenteric lymphangiography did not. Postligation lymphangiography was not of value in identifying incomplete ligation.     

Rectal and Colonic Injury in the Llama Anatomic Considerations and Surgical Management in Four Llamas

Transrectal palpation in llamas can result in iatrogenic rectal and colonic injury. The purpose of this report is to define the caudal extent of the peritoneal cavity in llamas and to describe the surgical management of rectal or colonic injuries in four llamas. Measurements were made of six adult llamas during necropsy. The mean distance from the peritoneal reflection to the anus was 3.9 ± 0.1 cm (3.4 - 4.3 cm). Four llamas were examined for rectal or colonic perforations. One laceration was of partial thickness and three lacerations were of full thickness. Two of the defects were repaired by a transanal approach and two by celiotomy to facilitate removal of fecal debris and abdominal lavage. Successful repair of the rectal or colonic tears was achieved in all four llamas. Wound infection and incisional hernia occurred in both llamas that underwent celiotomy. Two llamas died 3 and 18 months later, and two llamas have survived 2 years. Rectal tears in llamas are accompanied by a high risk of peritoneal contamination, and primary closure is recommended. If fecal contamination of the abdomen has occurred, celiotomy is indicated to allow mechanical removal of fecal debris and peritoneal lavage.     

Repair of Facial Defects with Periosteal Flaps in Two Horses

Facial defects that extended into the sinuses of two horses were repaired by using adjacent periosteum to cover the defects, using either a single flap or double flap technique. Acceptable cosmetic appearance was restored in both horses. Resistance to penetration of a needle and ultrasonic scanning demonstrated bony bridging in one horse.     

Surgical Wound Infection Rates in Dogs and Cats Data from a Teaching Hospital

Two thousand sixty-three surgical procedures were performed on 1992 patients (1715 dogs and 277 cats). In a retrospective analysis, the procedures were categorized according to the expected degree of wound contamination, and corresponding wound infection rates were determined. The number of procedures in each category and the percent that became infected were as follows: clean (1100, 2.5%), clean-contaminated (554, 4.5%), contaminated (172, 5.8%), and dirty (237, 18.1%). The administration of antibiotics significantly reduced the frequency of wound infection in clean surgical procedures performed by senior veterinary students (p less than 0.05), but not in clean elective procedures performed by faculty or resident surgeons that required 90 minutes or less to complete. There was a significant correlation between elevation of rectal temperature postoperatively and increased duration of the surgical procedure. However, the rectal temperature measured the day after surgery was not an accurate predictor of wound infection.