Evaluation of the Element point-of-care blood gas analyzer for use in horses.

OBJECTIVE: To compare the Element point-of-care (POC) portable blood gas analyzer with a laboratory-based bench-top reference analyzer using whole blood samples obtained from horses presenting to a referral center with various disorders in order to determine agreement between these analyzers. DESIGN: Prospective clinical study. SETTING: The study was conducted at a university teaching hospital at moderate altitude. ANIMALS: One hundred paired samples from 80 horses >1 year of age were collected after obtaining informed client consent. Fifty paired samples were from patients admitted for elective procedures and considered to be healthy, and 50 paired samples were emergency admissions and considered to be critically ill. MEASUREMENTS AND MAIN RESULTS: Paired whole blood samples were evaluated on both the Element POC and Radiometer ABL 800 FLEX analyzers simultaneously, and results were compared. Pearson correlation coefficients between analyzers were calculated. To assess agreement, scatter and Bland-Altman plots were evaluated, and mean difference and 95% limits of agreement were calculated for each analyte. Correlation was either good (0.8-0.92) or excellent (>0.93) for the majority of analytes. All analytes apart from hemoglobin had acceptable agreement, with ≥80% of individual results within agreement targets. Precision targets were acceptable for most analytes, with partial pressure of carbon dioxide (pCO2 ) and calcium (Ca2+ ) exceeding precision targets. CONCLUSIONS: The portable Element POC system had acceptable agreement with the ABL 800 FLEX bench-top analyzer currently in use at the study center when evaluating the majority of analytes from equine whole blood samples.

Pharmacokinetics and pharmacodynamics of clodronate disodium evaluated in plasma, synovial fluid and urine.

BACKGROUND: Clodronate is a non-nitrogenated bisphosphonate approved for use in horses. There are no peer-reviewed published reports describing the pharmacokinetics or evaluating renal health indices and urinary excretion patterns in conjunction with plasma and synovial fluid concentration following the systemic administration of clodronate to horses. OBJECTIVES: Describe clodronate concentrations in plasma, urine and synovial fluid and evaluate the effects on renal indices after intramuscular administration to healthy horses. STUDY DESIGN: Experimental study with repeated measures. METHODS: Six healthy adult horses received a single intramuscular dose of clodronate (1.8 mg/kg). Blood, synovial fluid and urine were collected prior to and after administration of clodronate up to 72, 48 and 168 hours respectively. Drug concentrations were measured using LC-MS/MS and noncompartmental pharmacokinetic analysis was performed. Renal function indices were also evaluated. RESULTS: Clodronate was quantifiable for up to 24 hours in plasma and 48 hours in synovial fluid and detected at all time points in urine. Maximum plasma concentration of clodronate 210 ± 68.2 ng/mL occurred at approximately 34.8 ± 0.2 minutes after administration, while peak synovial concentration (57.7 ± 32.8 ng/mL) occurred at 2.67 ± 2.32 hours after administration and peak urine concentration (88 358.2 ± 79 521.4 ng/mL) occurred at 2.67 ± 2.58 hours post administration. Terminal half-life in plasma was 3.32 ± 1.25 and was 4.8 ± 3.05 hours in synovial fluid. Creatinine concentrations rose significantly after treatment but remained within normal adult reference ranges at all times. MAIN LIMITATIONS: Limited number of animals and sampling times and the absence of urine collection for determination of concentration beyond 7 days. CONCLUSIONS: Clodronate is rapidly cleared from the blood and synovial fluid. It has variable and biphasic urinary excretion. While significant increase in blood creatinine concentrations was present after a single intramuscular dose of clodronate, values were never above the normal reference range. Further studies are warranted in horses undergoing exercise and those undergoing multiple dosing schemes.

A retrospective cohort study of racing performance in Quarter Horses undergoing prosthetic laryngoplasty for treatment of recurrent laryngeal neuropathy.

OBJECTIVE To determine effects of prosthetic laryngoplasty on return to racing, performance index, and career longevity in racing Quarter Horses with recurrent laryngeal neuropathy (RLN) and to evaluate performance variables for horses with RLN undergoing prosthetic laryngoplasty, compared with a control horse population. DESIGN Multicenter, retrospective cohort study. ANIMALS 162 racing Quarter Horses with RLN treated with prosthetic laryngoplasty (case horses) and 324 racing Quarter Horse without RLN (control horses). PROCEDURES Medical and race records of case and control horses examined at 5 referral centers between January 2000 and December 2015 were reviewed retrospectively. Two control horses were matched with each case horse. Return to racing, earnings, number of racing starts, performance index, and career longevity were evaluated. RESULTS The odds of returning to racing did not differ significantly between case and control horses but decreased with increasing age. Neither racing starts nor career longevity were affected by prosthetic laryngoplasty or by RLN grade. In fact, horses undergoing laryngoplasty for treatment of RLN and horses with the lowest RLN grade before surgery had higher performance indices after the surgery, compared with indices for control horses. CONCLUSIONS AND CLINICAL RELEVANCE The faster speeds and shorter distances raced with Quarter Horses could alter how RLN impacts respiratory variables and performance in Quarter Horses, compared with other racehorse breeds. Further study is needed to understand the impacts of RLN and surgical treatments for RLN in racing Quarter Horses.

Surgical correction of nephrosplenic entrapment of the large colon in 3 horses via standing left flank laparotomy.

OBJECTIVE: To describe a technique for surgical correction of nephrosplenic entrapment via standing left flank laparotomy. STUDY DESIGN: Case series. ANIMALS: Horses (n = 3). METHODS: Nephrosplenic entrapment was diagnosed by abdominal palpation per rectum in all 3 horses and confirmed by transabdominal ultrasonography in 2 horses. Duration of colic was variable and failed to resolve after medical management, phenylephrine administration, and jogging. With sedation and local analgesia, standing left flank laparotomy using a modified grid approach was performed to correct the entrapment. Follow-up information was obtained by telephone communication with trainers or owners. RESULTS: Nephrosplenic entrapment was successfully corrected in all horses; postoperative fever occurred in 1 horse. Horses were discharged after 48-72 hours and returned to previous use within 30 days. CONCLUSION: Standing flank laparotomy is an alternative for horses with nephrosplenic entrapment unresponsive to medical therapy when general anesthesia and exploratory celiotomy are not an option because of financial constraints or a high anesthetic risk. This approach leads to a favorable outcome, reduces hospital stay and associated costs and leads to a rapid return to function.

Evaluation of plasma muscle enzyme activity as an indicator of lesion characteristics and prognosis in horses undergoing celiotomy for acute gastrointestinal pain.

BACKGROUND: In horses undergoing celiotomy for acute gastrointestinal pain, identification of variables correlating with lesion severity and location, and survival provide veterinarians and owners with information that aids in making informed decisions regarding appropriate treatment. Muscle enzyme activity is often increased in horses undergoing celiotomy for acute gastrointestinal pain and it is not known if muscle enzyme activity increase is specific to lesion type or impacts prognosis for survival. The objective of this study was to evaluate the relationship of pre-operative increase in muscle enzyme activities with intestinal lesion characteristics, specifically lesion location (large versus small intestine) and whether it was strangulating versus nonstrangulating, and case survival in horses undergoing celiotomy for acute gastrointestinal pain. METHODS: Records of 241 horses undergoing exploratory laparotomy for colic were reviewed retrospectively. Evaluation of preoperative plasma aspartate aminotransferase (AST), creatine kinase (CK), sorbitol dehydrogenase (SDH), and gamma-glutamyltransferase (GGT) activities, fibrinogen and glucose concentrations, and hematocrit (HCT) and their association with gastrointestinal lesion characteristics and survival was performed. RESULTS: Pre-operative increase in plasma CK and AST activity, and HCT and decrease in plasma bilirubin concentration were significantly associated with presence of lesions resulting in intestinal ischemia. Increase in plasma CK activity and HCT were significantly associated with a decreased probability of survival to hospital discharge. Plasma GGT and SDH activity, and glucose and fibrinogen concentration were not significantly associated with survival or severity of disease in multivariate analysis. CONCLUSIONS: Plasma muscle enzyme activity may be useful as a prognostic indicator in equine colic cases. Given that increases in plasma CK and AST activity were significantly associated with nonsurvival and the presence of intestinal ischemia, preoperative increase in these enzyme activities could assist in identification of disease severity and prognosis of horses undergoing celiotomy for acute gastrointestinal pain. Further study is indicated to elucidate the etiology of increased muscle enzyme activity in horses with surgical colic disease observed in this preliminary study.