Search Results

You are looking at 11 - 20 of 32 items for

  • Author or Editor: James K. Roush x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective—To measure ocular effects (blood-aqueous barrier breakdown and intraocular pressure [IOP]) following aqueocentesis performed with needles of various sizes in dogs.

Animals—28 healthy adult dogs.

Procedures—24 dogs underwent unilateral aqueocentesis (24 treated eyes and 24 contra-lateral untreated eyes); 25-, 27-, or 30-gauge needles were used in 3 treatment groups (n = 8/group). Four dogs were untreated controls. Aqueocentesis was performed during sedation and topical anesthesia. Anterior chamber fluorophotometry was performed before and after aqueocentesis on day 1. On days 2 through 5, sedation and fluorophotometry were repeated. Intraocular pressure was measured with a rebound tonometer at multiple time points.

Results—Aqueocentesis resulted in blood-aqueous barrier breakdown detected via fluorophotometry in all treated eyes, with barrier reestablishment by day 5. On day 2, the contralateral untreated eyes of all 3 groups also had significantly increased fluorescence. Use of a 25-gauge needle resulted in a significant increase in treated eyes' anterior chamber fluorescence on days 3 and 5 as well as a significant increase in IOP 20 minutes following aqueocentesis, compared with the other treatment groups.

Conclusions and Clinical Relevance—Aqueocentesis performed with a 25-gauge needle resulted in the greatest degree of blood-aqueous barrier breakdown and a brief state of intraocular hypertension. Use of a 27- or 30-gauge needle is recommended for aqueous paracentesis. A consensual ocular reaction appeared to occur in dogs following unilateral traumatic blood-aqueous barrier breakdown and may be of clinical importance.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To perform repeated anterior chamber fluorophotometry on both eyes of ophthalmologically normal dogs to measure fluorescein concentrations over a 5-day period and identify any change in the degree of anterior chamber fluorescence over time or difference between eyes.

Animals—9 healthy adult dogs (18 eyes).

Procedures—Each dog received an IV injection of 10% fluorescein solution, and anterior chamber fluorophotometry was performed 1 hour later on both eyes. This procedure was repeated at the same time each day for 5 consecutive days.

Results—A significant increase in fluorescein concentration was evident in the anterior chamber on day 5 in the right eye and days 2, 3, 4, and 5 in the left eye. There was no significant difference in concentration between the left and the right eyes on any day.

Conclusions and Clinical Relevance—The increase in ocular fluorescein concentration in the study dogs was unlikely to be of clinical importance and is only pertinent for subsequent research studies. This is a limitation that should be considered when reporting fluorophotometry data as fluorescein concentration or as change in fluorescein concentration from baseline.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To measure strain in the common calcaneal tendon during trotting in dogs and to compare strain before and after immobilization of the tarsal joint.

Animals—6 dogs.

Procedures—A microminiature strain gauge was surgically implanted on the tendinous portion of the gastrocnemius muscle. Surface electromyography (EMG) values, percentage strain, and ground reaction forces were measured before and after immobilization. Peak vertical force; vertical impulse; initial, maximum, and final strain; and peak-to-peak EMG amplitude were recorded. Data were analyzed by use of a repeated-measures ANOVA and paired t tests.

Results—Timing of strain data correlated closely with foot strike of the hind limb and EMG activity in all dogs. Maximum tendon strain was simultaneous with peak vertical force. Continued muscle contraction was evident after immobilization. There was no significant difference in maximum strain after immobilization, compared with maximum strain during normal motion. Minimum strain, both at the beginning and end of the strain curve, was sig-nificantly decreased for the immobilized state, compared with results for nonimmobilized joints.

Conclusions and Clinical Relevance—Immobilization of the tarsal joint did not eliminate calcaneal tendon strain during weight bearing in dogs. Decreased isometric muscle contraction during the swing phase of the gait could account for smaller minimum strain in immobilized joints. Immobilization is frequently applied after Achilles tendon rupture to alleviate strain and force on the sutured repair, with possible complications because of the immobilization method. Consideration of these findings could be important in adjusting current treatment recommendations.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate clinical efficacy of hydrocodone-acetaminophen and tramadol for treatment of postoperative pain in dogs undergoing tibial plateau leveling osteotomy (TPLO).

ANIMALS 50 client-owned dogs.

PROCEDURES Standardized anesthetic and surgical protocols were followed. Each patient was randomly assigned to receive either tramadol hydrochloride (5 to 7 mg/kg, PO, q 8 h; tramadol group) or hydrocodone bitartrate–acetaminophen (0.5 to 0.6 mg of hydrocodone/kg, PO, q 8 h; hydrocodone group) for analgesia after surgery. The modified Glasgow composite measure pain scale was used to assess signs of postoperative pain at predetermined intervals by an investigator who was blinded to treatment group. Scoring commenced with the second dose of the assigned study analgesic. Pain scores and rates of treatment failure (ie, dogs requiring rescue analgesia according to a predetermined protocol) were compared statistically between groups.

RESULTS 12 of 42 (29%; 5/19 in the hydrocodone-acetaminophen group and 7/23 in the tramadol group) dogs required rescue analgesic treatment on the basis of pain scores. Median pain score for the hydrocodone group was significantly lower than that of the tramadol group 2 hours after the second dose of study analgesic. The 2 groups had similar pain scores at all other time points.

CONCLUSIONS AND CLINICAL RELEVANCE Overall, differences in pain scores between dogs that received hydrocodone-acetaminophen or tramadol were minor. The percentage of dogs with treatment failure in both groups was considered unacceptable.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate the pharmacokinetics of hydrocodone (delivered in combination with acetaminophen) and tramadol in dogs undergoing tibial plateau leveling osteotomy (TPLO).

ANIMALS 50 client-owned dogs.

PROCEDURES Dogs were randomly assigned to receive tramadol hydrochloride (5 to 7 mg/kg, PO, q 8 h; tramadol group) or hydrocodone bitartrate–acetaminophen (0.5 to 0.6 mg of hydrocodone/kg, PO, q 8 h; hydrocodone group) following TPLO with standard anesthetic and surgical protocols. Blood samples were collected for pharmacokinetic analysis of study drugs and their metabolites over an 8-hour period beginning after the second dose of the study medication.

RESULTS The terminal half-life, maximum serum concentration, and time to maximum serum concentration for tramadol following naïve pooled modeling were 1.56 hours, 155.6 ng/mL, and 3.90 hours, respectively. Serum concentrations of the tramadol metabolite O-desmethyltramadol (M1) were low. For hydrocodone, maximum serum concentration determined by naïve pooled modeling was 7.90 ng/mL, and time to maximum serum concentration was 3.47 hours. The terminal half-life for hydrocodone was 15.85 hours, but was likely influenced by delayed drug absorption in some dogs and may not have been a robust estimate. Serum concentrations of hydromorphone were low.

CONCLUSIONS AND CLINICAL RELEVANCE The pharmacokinetics of tramadol and metabolites were similar to those in previous studies. Serum tramadol concentrations varied widely, and concentrations of the active M1 metabolite were low. Metabolism of hydrocodone to hydromorphone in dogs was poor. Further study is warranted to assess variables that affect metabolism and efficacy of these drugs in dogs.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether addition of a continuous, local infusion of bupivacaine would improve postoperative analgesia in dogs undergoing total ear canal ablation.

Design—Randomized controlled trial.

Animals—16 dogs undergoing total ear canal ablation (12 unilaterally and 4 bilaterally with > 1 month between procedures).

Procedure—Dogs were randomly allocated to receive morphine (0.25 mg/kg [0.11 mg/lb]) at the end of the procedure (10 procedures) or morphine and a continuous, local infusion of bupivacaine (0.13 to 0.21 mg/kg/h [0.06 to 0.1 mg/lb/h]; 10 procedures). Dogs were observed for 48 hours after surgery. Additional doses of morphine were administered up to every 4 hours in dogs with signs of severe pain.

Results—Temperament, sedation, analgesia, and cumulative pain scores were not significantly different between groups any time after surgery. Recovery score was significantly higher for dogs that received bupivacaine than for control dogs 2 hours after extubation but not at any other time. Serum cortisol concentration was not significantly different between groups at any time but, in both groups, was significantly increased at the time of extubation, compared with all other observation times. Total number of additional doses of morphine administered was not significantly different between groups. Bupivacaine was not detected in the plasma of any of the dogs that received the local bupivacaine infusion.

Conclusions and Clinical Relevance—Results suggest that addition of a continuous, local infusion of bupivacaine did not significantly increase the degree of postoperative analgesia in dogs that underwent total ear canal ablation and were given morphine at the end of surgery. (J Am Vet Med Assoc 2005;227:414–419)

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To evaluate the effects of topical ophthalmic application of 0.5% proparacaine hydrochloride solution (PHCL; containing 0.01% benzalkonium chloride as preservative) on aerobic bacterial culture results for naturally occurring infected corneal ulcers in dogs.

DESIGN Clinical trial.

ANIMALS 25 client-owned dogs with infected corneal ulcers (24 unilaterally affected and 1 bilaterally affected; only 1 eye included/dog) examined between June 2008 and May 2011.

PROCEDURES Swab samples for aerobic bacterial culture were collected from the periphery of each corneal ulcer before and approximately 1 minute after topical ophthalmic application of 1 drop of PHCL. Numbers of aerobic bacterial species isolated from affected eyes were compared between sample collection points and between other variables (ie, side [left or right] of affected eye, prior treatments, and patient age, sex, and neuter status).

RESULTS There was no significant difference between numbers of aerobic bacterial species isolated per eye or overall aerobic bacterial culture results (positive or negative) before versus after PHCL application. Similarly, prior treatment had no significant effect on aerobic bacterial culture results for samples collected at either point. The most commonly isolated bacteria before and after PHCL application were Staphylococcus spp (40% and 48%, respectively), followed by Streptococcus spp (23% and 22%, respectively).

CONCLUSIONS AND CLINICAL RELEVANCE Topical ophthalmic application of PHCL did not significantly affect aerobic bacterial culture results for naturally occurring infected corneal ulcers in dogs as assessed in this study. Therefore, topical ophthalmic PHCL application could be useful in clinical settings prior to sample collection to relieve patient discomfort and to aid in sample acquisition without compromising aerobic bacterial culture results.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To assess the time to completion, number of errors, and knot-holding capacity (KHC) for starting and ending square knots (SSKs and ESKs) of a continuous pattern and Aberdeen knots tied by veterinary students and to investigate student perceptions of knot security and knot-tying difficulty for the 3 knot types.

SAMPLE

16 second-year veterinary students.

PROCEDURES

Students created 3 (4-throw) SSKs, 3 (5-throw) ESKs, and 3 (3 + 1 configuration) Aberdeen knots with 2-0 polydioxanone on a custom test apparatus. Time to complete each knot, the number of errors in each knot, and student ratings of knot-tying difficulty and confidence in knot security were recorded. Each knot was tested to failure on a uniaxial tensiometer to determine KHC and mode of failure. Variables of interest were compared by repeated-measures ANOVA or the Friedman test with post hoc pairwise comparisons.

RESULTS

Mean knot completion time for Aberdeen knots was significantly less than mean completion time for SSKs or ESKs. Mean KHC was significantly lower for ESKs than for SSKs; KHC for Aberdeen knots was not compared with these values because of methodological differences. Median error rate was higher for ESKs than for other knot types. Mean difficulty rating for Aberdeen knots was lower than that for ESKs. Most tested knots failed by breakage at the knot.

CONCLUSIONS AND CLINICAL RELEVANCE

Aberdeen knots appeared to be easy for veterinary students to learn and were completed more rapidly and with fewer errors than ESKs. Including this type of knot in surgical skills curriculum for novices may be beneficial.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective

The objective of the study reported here was to evaluate the effects of changing velocity on stance time and ground reaction force (GRF) measurements in horses at the walk and trot.

Design

Force plate gait analysis was used to evaluate clinically normal horses at variable velocities. Ground reaction force measurements and stance times were recorded and compared.

Animals

12 adult horses.

Procedure

Data were obtained from 192 valid trials at the walk and 162 valid trials at the trot. Vertical, braking, and propulsive peak forces and impulses were measured. Pearson’s correlation coefficients were determined for velocity and stance time and all measured forces and impulses in the forelimbs and hind limbs. Trials were divided into distinct velocity ranges. Trials obtained at velocities within the established ranges were analyzed to evaluate changes in vertical, braking, and propulsive peak forces and impulses at differing speeds within the walk and trot gaits.

Results

At the walk and trot, a significant negative correlation was found between velocity and forelimb and hind limb stance times. Velocity and stance time were significantly correlated with many of the GRF and impulse measurements. Velocity was significantly correlated with vertical and braking forces in the hind limbs at the walk, with vertical force in the forelimbs at the trot, and with braking force in the forelimbs and hind limbs at the trot. Velocity and stance time correlated significantly with forelimb and hind limb vertical impulses. Forelimb and hind limb stance times decreased significantly as velocity increased. Hind limb braking force increased and forelimb and hind limb vertical impulses decreased significantly as walk velocity increased. Forelimb braking force increased significantly between velocity ranges at the trot.

Conclusions

Results of this study confirm that a significant negative linear correlation exists between subject velocity and stance times in clinically normal horses at the walk and trot. Significant correlations were also identified between velocity and many GRF measurements, indicating that subject velocity does influence the generation of GRF measurements in horses. Variation in subject velocity should be minimized when performing force-plate analysis in horses. (Am J Vet Res 1996;57:7-11)

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association