Cardiovascular Function and Serum Catecholamine Concentrations after Anesthesia and Surgery in the Dog

Peripheral vasoconstriction and plasma catecholamine concentrations were studied in 37 dogs after cervical disc fenestration and salivary gland excision, laparotomy for intestinal anastomoses and cystotomy, or laparotomy for repair of diaphragmatic rupture, gastrotomy, and pyloromyotomy. Meperidine (4.4 mg/kg) was administered before extubation of 12 dogs undergoing laparotomy. Heart rate, respiratory frequency, indirect blood pressure, rectal temperature, toe web temperature, and plasma concentrations of epinephrine and norepinephrine were determined before induction of anesthesia, after intubation, after extubation, at sternal recumbency, and at standing. All dogs were hypothermic during surgery. After surgery, peripheral hypothermia (large rectal-toe web temperature gradients) increased from a mean of 4.6 degrees C after intubation to a mean of 10.4 degrees C when the dogs initially stood. Heart and respiratory rates and blood pressures during recovery were similar to those before anesthesia. Mean plasma catecholamine concentrations were neither significantly higher during recovery than before surgery nor were they increased in any surgical group, including the dogs not treated with meperidine. After anesthesia, 15% of the epinephrine and 12% of the norepinephrine samples were more than two standard deviations above the mean of the preanesthetic concentrations of all dogs. The ratio of all dogs with an epinephrine concentration more than two standard deviations above the mean of baseline epinephrine concentrations was greater at sternal recumbency than before anesthesia and the ratio of dogs with an increased epinephrine concentration at sternal recumbency was greater in the laparotomy dogs (9 of 24) than in the cervical surgery dogs (0 of 12).(ABSTRACT TRUNCATED AT 250 WORDS)     

AN INFECTED HIP PROSTHESIS IN A DOG DIAGNOSED WITH A 99mTC-CIPROFLOXACIN (INFECTON) SCAN

This case report describes the use of the 99mTc-labeled radiopharmaceutical ciprofloxacin (Infecton) in a case of hip prosthesis loosening in a dog. Serial planar radiographs were not conclusive, and culture of the synovial fluid was negative. Antibiotic treatment did not result in improvement of the lameness. Scintigraphy was performed with 99-Tc-Infecton, a tracer claimed to be specific for infection. Antibiotic treatment was interrupted 6 weeks prior to the examination. Planar and tomographic images at 3 h and at 24 h postinjection showed increased activity along the acetabulum and the proximal femoral bone surrounding the femoral prosthesis, indicating focal infection. Bacteriology performed after removal of the implant revealed Pseudomonas aeruginosa.     

Oropharyngeal dysphagias in the dog: A cinefluorographic analysis of experimentally induced and spontaneously occurring swallowing disorders

Cinefluorography and videofluorography were used to record and analyze functional swallowing deficits of 12 dogs with spontaneously occurring oropharyngeal dysphagias and six experimental dogs with selected neurectomies. Ten of the 12 dogs had dysphagias affecting the cricopharyngeal stage of the oropharyngeal phase of swallowing. Two dogs had mixed oropharyngeal dysphagias. Clinical signs of cricopharyngeal dysphagia could not be differentiated from those of dysphagias due to pharyngeal or mixed oropharyngeal deficits. Signs of cricopharyngeal dysphagia consisted of: 1) repeated attempts to swallow; 2) excessive head movement; 3) dropping food from the mouth after unsuccessful swallowing attempts; 4) reingestion of dropped food. Nine of these dogs had cinefluorographic evidence of asynchrony between the normal pharyngeal contraction and relaxation, and subsequent cricopharyngeal relaxation and contraction. Only one dog demonstrated a consistent cricopharyngeal non-opening (achalasia). Seven of the dogs responded dramatically to cricopharyngeal myotomy. Two dogs with mixed oropharyngeal dysphagias had poor contractility of the pharyngeal muscles in addition to cricopharyngeal dysphagia. Clinical and cinefluorographic evaluation following cricopharyngeal myotomy of one dog verified exacerbation of functional deficits due to the iatrogenic cricopharyngeal chalasia. Esophagopharyngeal reflux accentuated the contrast medium retention in the pharynx and laryngotracheal aspiration. The need was stressed for careful differentiation between cricopharyngeal dysphagia and dysphagias involving the pharyngeal stage. Four experimental dogs with selective bilateral neurectomies of branches of the glossopharyngeal (IX) and vagus (X) nerves were evaluated clinically and cinefluorographically in an attempt to identify the pathogenesis of cricopharyngeal dysphagia. The variable results in the four dogs and the observed recovery in two dogs suggested that peripheral motor nerve deficits are not a major cause of cricopharyngeal dysphagia. Glossopharyngeal neurectomy in two dogs induced a profound functional disorder involving the pharyngeal and cricopharyngeal stages and the esophageal phase of swallowing. This would support a new hypothesis that the glossopharyngeal nerve is sensory to the esophagus as well as the pharynx, and may play a major role in disorders of the pharynx, upper esophageal sphincter, and esophagus, including congenital or acquired megaesophagus.     

Controlled Tissue Expansion in the Distal Extremities of Dogs

Controlled tissue expansion using a 100 cc rectangular silicone elastomer expander was performed in the mid-antebrachium and mid-crus of eight adult mixed-breed dogs. Two expander inflation schedules were followed. Group 1 dogs (n = 4) underwent expander inflation using 10 cc sterile saline every other day, and group 2 dogs (n = 4) underwent expander inflation using 15 cc sterile saline every other day until the nominal volume (100 cc) was attained. Significant mean postexpansion increases in skin surface area of 94.1 cm² (35.9%) and 108.9 cm² (37.3%) were measured in the antebrachium and crus, respectively (p < .05). In a second procedure, the expanders were removed and skin flaps were developed from the redundant tissue generated during the expansion process. Single pedicle advancement flaps and transposition flaps were used to cover surgically created defects measuring 5 times 10 cm in the antebrachium and cms. Single pedicle advancement flaps consistently measured 10 × 10 cm and could be advanced to cover defects involving one third of the mid-antebrachial or mid-crural circumference. Transposition flaps were rotated up to 170 and the donor site defects were easily closed under minimal or no tension. Complications included an abscess in one dog and seroma formation in four dogs. Differences in success or complication rates between group 1 dogs and group 2 dogs were not observed; an accelerated inflation schedule using 15 cc sterile saline every other day was recommended.     

Quantitative Ingrowth Analysis of a Porous-coated Acetabular Component in a Canine Model

Histomorphometric analysis of bone ingrowth into a porous-coated acetabular component was evaluated in a canine model. A total of nine prostheses were evaluated, 3 at 6 months, 3 at 12 months, and 3 at 24 months after implantation. All implants were grossly stable at the time of retrieval. The mean percentage of bone ingrowth was 12% at 6 months, 24% at 12 months, and 24% at 24 months. Narrow radiolucent lines noted on microradiographs were more evident at the 6 month time period than at the 12 or 24 month time periods. Bone ingrowth into a porous-coated acetabular component in a weight-bearing model may continue beyond the 6 month time period, and early evaluation of bone ingrowth may underestimate final bone ingrowth.     

Interleukin 2 (IL-2) production by mitogen stimulated bovine peripheral blood lymphocytes and its assay

Culture medium from bovine peripheral blood mononuclear cells stimulated with the mitogens phytohaemagglutinin (PHA) or Concanavalin A (Con A) was found to maintain the proliferation of Con A blasts in vitro. The factor responsible for this activity was not absorbable with bovine erythrocytes or fresh peripheral blood lymphocytes but was removed by Con A blasts. Production of this factor was dependent on the dose of mitogen used and was greatest after 24 h culture compared to 48 h. Quantitative determinations of factor activity in supernatants were carried out by regression analysis of logit transformed data from assays measuring the maintenance of Con A blast proliferation by supernatants.     

PULSED WAVE-DOPPLER ULTRASONOGRAPHIC EVALUATION OF THE COMMON CAROTID ARTERY IN THE RESTING HORSE: PHYSIOLOGIC DATA

A pulsed wave-Doppler ultrasonographic evaluation of common carotid arterial blood flow was carried out on 63 healthy Italian Saddlebred horses. Vessel diameter and tracing morphology were evaluated were evaluated and blood flow parameters (systolic, diastolic and mean velocity, acceleration and deceleration of the systolic wave, cartid pulse volume) were calculated and correlated with class variables (sex, age and body weight). On the basis of the presence of an incisure in the ascending branch of the systolic curve, subjects were divided in two groups: one with a bifid systolic curve and the other with a monophasic aspect. Correlations between: 1) diameter of the vessel and body weight and 2) carotid pulse volume and flow velocity (systolic, diastolic and mean) were found. A greater systolic pulse volume was found in male subjects, in subjects with greater body weight and in those which had a monophasic systolic wave.