Intra-articular bupivacaine is a common analgesic used in dogs with orthopedic disease. Bupivacaine has been linked to chondrotoxicity. The mechanism for bupivacaine's chondrotoxicity is unknown, but may involve inflammation. Prostaglandin E2 (PGE2) is an inflammatory mediator and a marker of joint inflammation. The aim of this study was to compare synovial fluid PGE2 concentrations after a single intra-articular injection of bupivacaine with a saline control in normal canine stifles. We hypothesized that bupivacaine stifles would have a significantly elevated PGE2 concentration compared to controls. Stifles from eight healthy, adult Beagles were randomly selected as the treated stifle and infused with bupivacaine. The contralateral stifle was injected with saline. Synovial fluid was collected before and after injection. PGE2 was quantified using a commercial ELISA. Data were transformed and mixed model ANOVA was performed with significance set at p<0.05. There were no significant differences in PGE2 concentration between treatment groups or times. Samples acquired with one or two aspiration attempts had significantly lower PGE2 concentrations than samples with =3 aspiration attempts (p=0.001). When adjusted for number of attempts, PGE2 concentrations were significantly higher 24 (p=0.003) and 48 (p=0.041) hours after injection compared to baseline in the bupivacaine group, but not in the saline group. Intra-articular bupivacaine injection did not result in increased synovial fluid PGE2 concentrations compared to controls; however, multiple aspiration attempts did, suggesting that synovial fluid PGE2 concentration is sensitive to multiple fluid collection attempts. Future studies investigating synovial fluid inflammatory mediators should consider methods to minimize aspiration attempts. / M. S. / Intra-articular bupivacaine is a popular pain relief medication commonly used in joint surgery. Despite its historically wide use, bupivacaine has been scrutinized due to its potentially toxic effects on joint cartilage. Currently, the mechanism of this toxicity has not been identified, though it may be associated with inflammation. Prostaglandin E₂ (PGE₂) is considered an indicator of joint inflammation. The purpose of this study was to quantify the concentration of PGE₂ within the joint fluid following a single injection of bupivacaine in normal canine stifles as compared to a saline control. Eight healthy, adult Beagles were used for this study. Stifles were randomized into treatment (bupivacaine) or control (saline) groups such that each dog had one stifle infused with bupivacaine and the opposite stifle with saline. Joint fluid was collected at the following time points: before injection (T0), 30 minutes, 60 minutes, 24 hours and 48 hours. Samples were analyzed in duplicate for PGE₂ concentration. There was no significant effect of treatment group (bupivacaine vs. saline) or time on joint fluid PGE₂ concentration. The number of sampling attempts did have an effect. Samples acquired with only one or two attempts had significantly lower PGE₂ concentrations than samples that required 3 or more sampling attempts. When adjusted for number of attempts, PGE₂ concentrations were significantly higher 24 and 48 hours after injection compared to baseline within the bupivacaine group, but not the saline group. Intra-articular bupivacaine injection did not result in increased joint fluid PGE₂ concentration compared to saline control. The data indicates that joint fluid PGE₂ concentration is highly sensitive to fluid collection attempts.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/95970 |
| Date | 19 June 2018 |
| Creators | Giangarra, Jenna Elizabeth |
| Contributors | Biomedical and Veterinary Sciences, Barry, Sabrina L., Dahlgren, Linda A., Lanz, Otto I. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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