Prosthetic Mesh for Obliteration of the Nephrosplenic Space in Horses: 26 Clinical Cases.

OBJECTIVE: To report surgical complications, occurrence of post-obliteration colic, long term outcome, and return to previous function for horses treated with prosthetic mesh obliteration of the nephrosplenic space. STUDY DESIGN: Retrospective study. ANIMALS: Horses (n = 26) having nephrosplenic space obliteration using prosthetic mesh. METHODS: Horses undergoing mesh obliteration between January 2006 and May 2013 were included. A Proxplast™ mesh was secured to the nephrosplenic space with titanium helical coils in standing horses using laparoscopic technique. Perioperative data were obtained from the medical record and by telephone followup. Tests of proportion were used to compare the study population to the hospital colic population. Occurrence of colic within 1 year of obliteration was compared between horses where the diagnosis was confirmed at laparotomy and those diagnosed by abdominal palpation per rectum using a Fisher's exact test. RESULTS: All 26 horses undergoing mesh obliteration during the study period survived to discharge. Long term followup was available for 25 horses, with 23 returning to their previous level of function, and 21 alive at the time of followup. Cause of death was not associated with the surgical procedure in any case. Geldings and Warmbloods were overrepresented compared to the hospital colic population. Ten horses (38%) demonstrated colic after mesh obliteration. All 10 horses were examined by a veterinarian and none were diagnosed with recurrence of nephrosplenic entrapment. CONCLUSION: Mesh obliteration of the nephrosplenic space is an effective alternative to suture closure for preventing nephrosplenic entrapment of the large colon in horses. No complications related to mesh obliteration were reported in our study population.

Hemadsorption extracorporeal therapy removes cytokines ex vivo in horses.

OBJECTIVE: Plasma cytokine adsorption has shown benefit as an adjunctive therapy in human sepsis but has yet to be investigated in horses. We hypothesized that ex vivo filtration of equine plasma with a novel cytokine adsorption device would significantly reduce concentrations of lipopolysaccharide-stimulated cytokines. We also hypothesized that the device would adsorb medications commonly used to treat sepsis. ANIMALS: 8 horses owned by North Carolina State University. METHODS: Four liters of heparinized whole blood was collected from healthy adult horses (n = 8) and stimulated with lipopolysaccharide (100 ng/mL) for 6 hours (37 °C.) from June 4, 2023, to December 15, 2023. Plasma was filtered through a cytokine adsorption device or sham circuit. Samples were collected at 11 time points for multiplex cytokine analysis. Chemistry analysis was performed before and after filtration. To investigate the impact of the device on medication concentrations, equine plasma containing potassium penicillin, gentamicin, and flunixin meglumine was filtered through the cytokine adsorption device or sham for 6 hours. Drug concentrations before and after filtration were determined by ultra-high-performance liquid chromatography. Prefiltration versus postfiltration sample concentrations were analyzed by Student paired t test using GraphPad Prism 9.0 (P < .05). RESULTS: Filtration of lipopolysaccharide-stimulated equine plasma (n = 8) for 6 hours resulted in significant mean reductions in the cytokines IL-10, IL-5, IL-8, tumor necrosis factor-α (TNF-α), and IL-1ß, as well as albumin. Drug concentrations of potassium penicillin, gentamicin, and flunixin meglumine were also significantly reduced by filtration. CLINICAL RELEVANCE: This work provides proof of concept for further investigation of extracorporeal cytokine adsorption as a potential adjunct treatment for equine sepsis.

Feasibility of hemoperfusion using extracorporeal therapy in the horse.

Objective: Develop, implement, and monitor for adverse effects of, a novel hemoperfusion therapy in adult horses. Methods: A prospective, observational feasibility study using three healthy adult horses from the North Carolina State University teaching herd. Health status was determined by physical exam, complete blood count, coagulation panel, and serum biochemistry. Each horse was instrumented with a 14 Fr × 25 cm double-lumen temporary hemodialysis catheter and underwent a 240 min polymer-based hemoperfusion session. Horses were administered unfractionated heparin to maintain anti-coagulation during the session. Given the novelty of this therapy in horses, each horse was treated as a learning opportunity that informed an iterative process of protocol development and modification. Measurements and main results: Our long-term goal is to investigate potential clinical applications of hemoperfusion in horses, including cytokine reduction in horses with severe SIRS/sepsis. Horses were monitored for changes in clinical exam, biochemistry and hematology parameters. Additionally, cytokines were quantified to determine whether extracorporeal hemadsorption therapy alone caused an inflammatory response. Our results show that hemoperfusion therapy was associated with decreased platelet counts and serum albumin concentration. There was no significant change in plasma cytokine concentrations with hemoperfusion therapy. In one horse, the cytokine concentrations decreased, as previously reported with hemoperfusion therapy in humans. Hypothesis: We hypothesized that hemoperfusion therapy could be performed in healthy adult horses without significant adverse effects. Conclusion: Polymer-based hemoperfusion is a feasible extracorporeal therapy (ECT) modality for adult horses. Additional studies are needed to further establish clinical protocols, as well as establish efficacy of polymer-based hemoperfusion for treatment of various conditions in horses, including intoxications, immune-mediated conditions, and sepsis.

Development and Formative Evaluation of a Low-Fidelity Equine Castration Model for Veterinary Education.

Entrustable Professional Activities (EPAs) are units of activity that early-stage professionals perform in the workplace that necessitate simultaneous integration of multiple competencies. EPA #6 requires students to perform a common surgical procedure on a stable patient, including pre-operative and post-operative management. Castration is one of the most common surgeries performed by equine primary care practitioners and is considered an "entry-level competency" for veterinary graduates entering equine private practice, however, to our knowledge there are no equine castration models available for veterinary student education. Therefore, we developed an inexpensive, low-fidelity model of equine field castration and evaluated it using a mixed-methods approach. Two different groups of students, with or without model experience, completed surveys before and after live horse castration. Students who used the model also completed model specific surveys. Videos of the students completing the model were evaluated by at least two different equine veterinary faculty using a 15-point rubric, and inter-rater reliability of the rubric was determined. After completing the model, students reflected on strengths and weaknesses of their performance. From our student survey results, we determined that student attitudes toward the model were mostly positive. Interestingly, there were several student attitudes toward the model that became significantly more favorable after live horse castration. Prior to live horse castration, there was no significant difference in confidence in model vs. no-model groups. Following live horse castration, students who used the model had higher confidence in procedure preparation and hand-ties than students who did not use the model, but they had lower scores for confidence during patient recovery. When reflecting on model castration, students most commonly cited preparation and surgical description as strengths, and ligature placement and hand-ties as weaknesses. Experts provided several suggestions to improve the model, including incorporation of emasculators and the need for better model stabilization. Our findings suggest that both students and veterinary educators feel that this low-fidelity model has educational value. Rubric performance metrics were favorable, but additional steps are needed to improve grading consistency among educators. Future research will determine whether student performance on the model is predictive of competence score during live-horse castration.

Evaluation of the analgesic and pharmacokinetic properties of transdermally administered fentanyl in goats.

OBJECTIVE: Evaluate the analgesic properties and pharmacokinetics of transdermal fentanyl patches (TFPs) in goats. DESIGN: Prospective, randomized study. SETTING: Preclinical Testing Facility at a University Teaching Hospital. ANIMALS: Thirty-four adult female Boer-cross goats. INTERVENTIONS: Goats underwent surgery as part of a concurrent orthopedic research study. Twelve hours prior to surgery, each goat received a TFP (target dosage of 2.5 µg/kg/h), or a placebo patch with analgesia provided by buprenorphine (0.01 mg/kg, IM, q 6 h). Patches were removed after 72 hours. Blood was sampled at specified intervals, up to 84 hours following TFP placement. Plasma concentrations of fentanyl (FEN) were determined using liquid chromatography-mass spectrometry. Postoperative pain assessments were performed by two independent blinded observers. MEASUREMENTS AND MAIN RESULTS: TFPs were applied at a mean (± standard deviation, SD) dose of 2.54 ± 0.36 µg/kg/h. No adverse events occurred. Pain scores between TFP and BUP groups were not significantly different at any time point. Mean plasma FEN concentration (± SD) 2 hours following patch application was 1.06 ± 0.85 ng/mL, and remained above 0.5 ng/mL for 40 hours. Maximum mean plasma FEN concentration (Cmax ) was 1.84 (ranging from 0.81 to 3.35) ng/mL with average time to maximum concentration (Tmax ) of 12 hours after patch application. CONCLUSIONS: TFP resulted in consistent FEN absorption and plasma concentrations within the human and ovine therapeutic ranges. Pain scores for goats administered TFP were not different than those administered buprenorphine. Ease of administration, duration of analgesia, and decreased dosing frequency make TFPs an attractive option for pain management in goats.

Colic in equine neonates: 137 cases (2000-2010).

OBJECTIVE: To document causes of colic in equine neonates, evaluate clinical features of neonates managed medically versus surgically, determine short- and long-term survival rates for neonates with specific medical and surgical lesions, and assess ability of patients to achieve intended use. DESIGN: Retrospective case series. ANIMALS: 137 client-owned equine neonates (< 30 days old) with a history of colic or signs of colic within 1 hour after hospital admission examined between 2000 and 2010. PROCEDURES: Signalment, history, results of physical examination, laboratory data, ancillary diagnostic tests, details of treatment, primary diagnosis, concurrent diseases and short-term survival rate were obtained from the medical records. Long-term follow-up information was obtained through phone survey. RESULTS: 137 neonates with colic were included. The majority (122 [89%]) of neonates were managed medically. The 3 most common diagnoses associated with colic were enterocolitis (37 [27%]), meconium-associated colic (27 [20%]), and transient medical colic (26 [19%]). The most common reason for surgery was small intestinal strangulating obstruction, and these neonates were more likely to have severe, continuous pain and were less responsive to analgesics. Concurrent diseases were common (87 [64%]) but did not significantly impact survival rate. Short-term survival rate was not significantly different between medically (75%) and surgically (73%) managed neonates. Long-term survival rate was excellent (66/71 [93%]) for horses that survived to hospital discharge. Most neonates surviving to maturity were used as intended (49/59 [83%]). CONCLUSIONS AND CLINICAL RELEVANCE: Most neonates examined for signs of colic can be managed medically. Short-term survival rate in medically and surgically treated neonates was good. Long-term survival rate of foals discharged from the hospital was excellent, with most achieving intended use.