Increasing tourniquet number has no effect on amikacin concentration within the radiocarpal joint in horses undergoing intravenous regional limb perfusion.

OBJECTIVE: To determine whether IV regional limb perfusion (IVRLP) performed in the cephalic vein with a wide rubber tourniquet (WRT) applied proximal and distal to the carpus results in a higher peak concentration (Cmax) of amikacin in the radiocarpal joint (RCJ), compared with the Cmax for IVRLP using a single WRT proximal to the carpus. ANIMALS: 7 healthy adult horses. PROCEDURES: Horses underwent IVRLP using standing sedation with 2 g of amikacin sulfate diluted to 60 mL by use of saline (0.9% NaCl) solution in the cephalic vein with 2 different tourniquet techniques; proximal WRT (P) and proximal and distal WRT (PD). Synovial fluid was collected from the RCJ at 5, 10, 15, 20, 25, and 30 minutes after IVRLP. Tourniquets were removed after the 30-minute sample was collected. Blood samples from the jugular vein were collected at 5, 10, 15, 20, 25, 29, and 31 minutes after IVRLP. Amikacin concentration was quantified by a fluorescence polarization immunoassay. Median peak concentration (Cmax) of amikacin and time to maximum drug concentration (Tmax) within the RCJ were determined. RESULTS: Median peak concentration in the RCJ was 1331.4 µg/mL with technique P and 683.1 µg/mL with technique PD. Median Tmax occurred at 30 minutes with technique P and 25 minutes with technique PD. No significant (Cmax, P = 0.18; Tmax, P = 0.6) difference in amikacin Cmax or Tmax between techniques was detected. CLINICAL RELEVANCE: Placement of 2 WRTs offers no advantage to a single proximal WRT when performing IVRLP to deliver maximal amikacin concentrations to the RCJ using IVRLP.

Orthopedic Infections-Clinical Applications of Intravenous Regional Limb Perfusion in the Field.

For the equine veterinarian, orthopedic emergencies are a common occurrence in clinical practice, with traumatic wounds of the distal limb and penetrating injuries of the hoof being some of the most common medical conditions to affect horses. Intravenous regional limb perfusion is a technique widely used for the treatment of orthopedic infections in horses. The objectives of this review are to discuss some of the clinical applications for this treatment modality in the field and to review the technique for the practitioner.

In vitro efficacy of a 0.2% polyhexamethylene biguanide-impregnated gauze dressing against pathogenic bacterial isolates found in horses.

OBJECTIVE: To determine the ability of 0.2% polyhexamethylene biguanide (PHMB)-impregnated gauze to inhibit the growth of bacteria isolated from equine infected sites. STUDY DESIGN: In vitro study. METHODS: Nine bacterial isolates were obtained from cultures submitted from equine patients presenting with penetrating injuries of the hoof (n = 4), septic osteitis (n = 1), synovial sepsis (n = 1), wounds (n = 2), and incisional infection following laparotomy (n = 1). Two standardized strains were also included. A standard inoculum of each isolate was placed on 12 Muller-Hinton agar plates. Squares (2.5 cm × 2.5 cm) of 0.2% PHMB-impregnated (n = 6) and nonimpregnated control gauze (n = 6) were placed on inoculated agar plates. Bacterial growth under each gauze square was assessed after a 24-h incubation period and areas of inhibition were measured to a standardized scale, using image-processing software. Mean ± SD growth inhibition (%) using 0.2% PHMB-impregnated gauze was compared to the nonimpregnated gauze for each isolate using Student's t test (p < .05). RESULTS: The 0.2% PMHB-impregnated gauze inhibited the growth of Staphylococcus spp. (n = 4) by 33%-83.1% and that of Escherichia coli spp. (n = 4) by 6.5%-37%. There was no inhibition of growth of Pseudomonas aeruginosa or either Enterococcus spp. CONCLUSION: The 0.2% PHMB-impregnated dressing tested here inhibited the growth of staphylococcal and E. coli isolates, but the magnitude of inhibition varied between strains. CLINICAL RELEVANCE: These results justify in vivo studies to evaluate the ability of the dressing to reduce the bacterial growth of common equine bacterial pathogens in clinical practice.

Time required to achieve maximum amikacin concentration in the synovial fluid of the tarsocrural joint following administration of the drug by intravenous regional limb perfusion in horses.

OBJECTIVE: To determine the median time to maximum concentration (tmax) of amikacin in the synovial fluid of the tarsocrural joint following IV regional limb perfusion (IVRLP) of the drug in a saphenous vein of horses. ANIMALS: 7 healthy adult horses. PROCEDURES: With each horse sedated and restrained in a standing position, a 10-cm-wide Esmarch tourniquet was applied to a randomly selected hind limb 10 cm proximal to the point of the tarsus. Amikacin sulfate (2 g diluted with saline [0.9% NaCl] solution to a volume of 60 mL) was instilled in the saphenous vein over 3 minutes with a peristaltic pump. Tarsocrural synovial fluid samples were collected at 5, 10, 15, 20, 25, and 30 minutes after completion of IVRLP. The tourniquet was removed after collection of the last sample. Amikacin concentration was quantified by a fluorescence polarization immunoassay. Median maximum amikacin concentration and tmax were determined. RESULTS: 1 horse was excluded from analysis because an insufficient volume of synovial fluid for evaluation was obtained at multiple times. The median maximum synovial fluid amikacin concentration was 450.5 µg/mL (range, 304.7 to 930.7 µg/mL), and median tmax was 25 minutes (range, 20 to 30 minutes). All horses had synovial fluid amikacin concentrations ≥ 160 µg/mL (therapeutic concentration for common equine pathogens) at 20 minutes after IVRLP. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that, in healthy horses, maintaining the tourniquet for 20 minutes after IVRLP of amikacin in a saphenous vein was sufficient to achieve therapeutic concentrations of amikacin in the tarsocrural joint.

Do allogeneic bone marrow derived mesenchymal stem cells diminish the inflammatory response to lipopolysaccharide infusion in horses? A pilot study.

Endotoxemia is a leading cause of morbidity and mortality in the equine industry, with colic being the most common cause of endotoxemia in horses. The objective of this study was to evaluate the safety and potential efficacy of a single dose of allogeneic equine bone marrow derived mesenchymal stem cells (BM-MSCs) in horses after the IV administration of lipopolysaccharide (LPS). Six horses were administered an IV infusion of 30 ng/kg LPS (O55:B5 Escherichia coli) in 500 ml saline over 30 min. Immediately after infusion test horses (n = 3) were administered 100 × 106 allogeneic BM-MSCs diluted in saline IV and control horses (n = 3) were administered saline. Clinicopathological data, pro-inflammatory cytokine measurements and sCD14 concentrations were compared between groups. No adverse reactions were observed in horses administered BM-MSCs intravenously. There were no significant differences between test and control horses with regard to clinicopathological values or pro-inflammatory cytokine production. At no time point did concentrations of sCD14 exceed the reference range in any horse. Results suggest that administration of a single IV dose of freshly cultured MSCs is safe and well-tolerated in horses with induced endotoxemia. Further study to evaluate their efficacy as a potential therapeutic in a larger number of horses with clinical disease is required.

Incidence of incisional complications after exploratory celiotomy in equids affected with enterolithiasis.

This study reports the prevalence of and risk factors for incisional complications in equids after ventral midline celiotomy for enterolithiasis. This study covered the years 2008 to 2015 and included 72 equids. Enteroliths were removed from the ascending or descending colon through 1 or more enterotomies. Complications were defined as surgical site infection and/or incisional hernia formation. Follow-up by telephone questionnaire or medical records determined that 10/72 (13.9%) equids experienced complications, with 6/72 (8.3%) developing a surgical site infection and 5/72 (6.9%) a hernia. Seven of ten were presented for chronic abdominal discomfort (> 24 hours), and 8/10 had right dorsal colon and pelvic flexure enterotomies. All equids that developed an incisional hernia and 4 with surgical site infection had enteroliths > 15 cm diameter removed from the right dorsal colon. Antimicrobial powder applied to the ventral midline incision during closure significantly reduced incisional complications. Removal of > 15 cm diameter enteroliths from the right dorsal colon may predispose to postoperative incisional complications.

Incidence des complications incisionnelles après une céliotomie exploratoire chez des équidés atteints d'entérolithiase. Cette étude rapporte la prévalence et les facteurs de risque des complications incisionnelles chez les équidés opérés pour l'entérolithiase en utilisant une celiotomie médiane ventrale de 2008 à 2015. Soixantedouze équidés ont été inclus. Les entérolithes ont été retirés du côlon ascendant ou descendant par ≥ 1 entérotomies. Les complications étaient définies comme une infection du site opératoire et/ou la formation d'une hernie incisionnelle. Le suivi a été obtenu par questionnaire téléphonique ou par dossiers médicaux. Dix des 72 (13,9 %) des équidés ont eu des complications, dont 6/72 (8,3 %) ont développé une infection du site opératoire et 5/72 (6,9 %) une hernie. Sept sur 10 ont été présentés pour un malaise abdominal chronique (> 24 heures) et 8/10 avaient des entérotomies du côlon dorsal droit et de la flexion pelvienne. Tous les équidés ayant développé une hernie incisionnelle et quatre avec une infection du site opératoire avaient des entérolithes > 15 cm de diamètre prélevés du côlon dorsal droit. La poudre antimicrobienne appliquée sur l'incision médiane ventrale lors de la fermeture réduisait significativement les complications incisionnelles. Le retrait d'entolithes de > 15 cm de diamètre du côlon dorsal droit peut prédisposer aux complications incisionnelles postopératoires.(Traduit par les auteurs).

Diagnostic value of plasma and peritoneal fluid procalcitonin concentrations in horses with strangulating intestinal lesions.

OBJECTIVE: To assess the diagnostic value of plasma and peritoneal fluid procalcitonin concentrations for identification of horses with strangulating intestinal lesions. ANIMALS: 65 horses with signs of colic of intestinal origin and 10 healthy (control) horses. PROCEDURES: For each horse, plasma and peritoneal fluid samples were obtained for a CBC and determination of total protein, procalcitonin, and lactate concentrations. Signalment and clinicopathologic findings were compared among control horses and horses with strangulating and nonstrangulating intestinal lesions. RESULTS: Mean ± SD plasma (274.9 ± 150.8 pg/mL) and peritoneal fluid (277 ± 50.6 pg/mL) procalcitonin concentrations for horses with colic were significantly greater than the mean ± SD plasma (175.5 ± 46.0 pg/mL) and peritoneal fluid (218.8 ± 48.7 pg/mL) procalcitonin concentrations for control horses. Mean procalcitonin concentration in peritoneal fluid, but not plasma, differed significantly between horses with strangulating lesions and those with nonstrangulating lesions. A peritoneal fluid procalcitonin concentration ≥ 281.7 pg/mL had a sensitivity of 81%, specificity of 69%, positive predictive value of 56.7%, and negative predictive value of 87.9% for detection of strangulating lesions. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that peritoneal fluid procalcitonin concentration, when evaluated in conjunction with other clinicopathologic results, might be a sensitive indicator of intestinal ischemia and facilitate early identification of horses that require surgery to address a strangulating lesion.

Evaluation of the risk of incisional infection in horses following application of protective dressings after exploratory celiotomy for treatment of colic.

OBJECTIVE To assess incidence of incisional infection in horses following management with 1 of 3 protective dressings after exploratory celiotomy for treatment of acute signs of abdominal pain (ie, colic) and determine the risk of complications associated with each wound management approach. DESIGN Prospective, randomized, controlled study. ANIMALS 85 horses. PROCEDURES Horses were assigned to 3 groups. After standardized abdominal closure, a sterile cotton towel (group 1) or polyhexamethylene biguanide-impregnated dressing (group 2) was secured over the incision site with 4 or 5 cruciate sutures of nonabsorbable monofilament, or sterile gauze was placed over the site and secured with an iodine-impregnated adhesive drape (group 3). Demographic and clinicopathologic data, intraoperative and postoperative variables, and development of complications were recorded and compared among groups by statistical methods. Follow-up information was collected 30 and 90 days after surgery. Incidence and odds of incisional complications were calculated. RESULTS 75 horses completed the study. Group 3 typically had dressing displacement necessitating removal during anesthetic recovery; dressings were in place for a mean of 44 and 31 hours for groups 1 and 2, respectively. Purulent or persistent serosanguinous incisional discharge (ie, infection) was detected in 11 of 75 (15%) horses (2/24, 0/26, and 9/25 from groups 1, 2, and 3, respectively). Odds of incisional complications were significantly greater for group 3 than for groups 1 or 2. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that risk of infection after celiotomy for treatment of colic is lower for incisions covered with sterile towels or polyhexamethylene biguanide-impregnated dressings secured with sutures than for incisions covered with gauze secured with iodine-impregnated adhesive drapes.

Predictive value of plasma and peritoneal creatine kinase in horses with strangulating intestinal lesions.

OBJECTIVE: To determine the ability of plasma and peritoneal creatine kinase (CK) to predict the presence of a strangulating lesion in horses presented for colic. STUDY DESIGN: Prospective clinical study. ANIMALS: Ten healthy control horses and 61 clinical colic cases. METHODS: Creatine kinase activity was measured in peritoneal fluid and plasma of 10 healthy horses and 61 horses presenting for colic (40 horses with nonstrangulating lesions and 21 horses with strangulating lesions). Information on other blood and peritoneal fluid variables, signalment, results from the physical examination, outcome, requirement for surgery, and lesion location and type were retrieved from the medical records of horses presenting for colic. RESULTS: A peritoneal CK cutoff level of 16 IU/L yielded a sensitivity of 95.2% and a specificity of 84.6% (positive predictive value [PPV] = 76.9% and negative predictive value [NPV] = 97%, respectively) for predicting a strangulating lesion. A peritoneal lactate cutoff level of 3.75 mmol/L yielded a sensitivity of 81% and a specificity of 92% (PPV = 85% and NPV = 90%, respectively) for predicting a strangulating lesion. CONCLUSION: Peritoneal CK concentration was a sensitive indicator of the presence of a strangulating lesion in horses presenting with colic, whereas peritoneal lactate concentration was a more specific indicator. CLINICAL SIGNIFICANCE: Measuring CK in peritoneal fluid may be a useful adjunct to clinical case presentation to accelerate the diagnosis and definitive treatment of horses presenting with strangulating intestinal lesions, thereby improving their outcome.

Catastrophic gastric rupture in a horse secondary to psyllium pharmacobezoars.

A mare was euthanized because of gastric rupture secondary to complete duodenal obstruction by 2 bezoars located in the pylorus and proximal duodenum. Infrared spectroscopy showed that the bezoars were composed of psyllium. The mare had been receiving treatment with a pelleted psyllium product at 4 times the recommended dosage. Veterinarians should be aware that treatment of colic in horses with pelleted psyllium products could be associated with gastric impaction.

Rupture gastrique catastrophique secondaire à des pharmacobézoards de psyllium en boulettes chez un cheval. Une jument a été euthanasiée en raison d'une rupture gastrique secondaire à une obstruction duodénale complète par deux bézoards situés dans le pylore et le duodénum proximal. La spectroscopie infrarouge a montré que les bézoards se composaient de psyllium. La jument avait reçu un traitement composé d'un produit de psyllium en boulettes à quatre fois la dose recommandée. Les vétérinaires devraient être au courant que le traitement des coliques chez les chevaux avec des produits de psyllium en boulettes pourrait être associé à une impaction gastrique.(Traduit par Isabelle Vallières).

Time required to achieve maximum concentration of amikacin in synovial fluid of the distal interphalangeal joint after intravenous regional limb perfusion in horses.

OBJECTIVE To determine the maximum concentration (Cmax) of amikacin and time to Cmax (Tmax) in the distal interphalangeal (DIP) joint in horses after IV regional limb perfusion (IVRLP) by use of the cephalic vein. ANIMALS 9 adult horses. PROCEDURES Horses were sedated and restrained in a standing position and then subjected to IVRLP (2 g of amikacin sulfate diluted to 60 mL with saline [0.9% NaCl] solution) by use of the cephalic vein. A pneumatic tourniquet was placed 10 cm proximal to the accessory carpal bone. Perfusate was instilled with a peristaltic pump over a 3-minute period. Synovial fluid was collected from the DIP joint 5, 10, 15, 20, 25, and 30 minutes after IVRLP; the tourniquet was removed after the 20-minute sample was collected. Blood samples were collected from the jugular vein 5, 10, 15, 19, 21, 25, and 30 minutes after IVRLP. Amikacin was quantified with a fluorescence polarization immunoassay. Median Cmax of amikacin and Tmax in the DIP joint were determined. RESULTS 2 horses were excluded because an insufficient volume of synovial fluid was collected. Median Cmax for the DIP joint was 600 µg/mL (range, 37 to 2,420 µg/mL). Median Tmax for the DIP joint was 15 minutes. CONCLUSIONS AND CLINICAL RELEVANCE Tmax of amikacin was 15 minutes after IVRLP in horses and Cmax did not increase > 15 minutes after IVRLP despite maintenance of the tourniquet. Application of a tourniquet for 15 minutes should be sufficient for completion of IVRLP when attempting to achieve an adequate concentration of amikacin in the synovial fluid of the DIP joint.

Clinical findings and management of 153 horses with large colon sand accumulations.

OBJECTIVE: To determine the influence of radiographic quantification of sand accumulation on the medical versus surgical management of large colon sand accumulations. To compare short- and long-term outcomes and complications associated with medical and surgical management of these horses. STUDY DESIGN: Retrospective. SAMPLE POPULATION: A total of 153 horses. METHODS: Medical records and abdominal radiographs of horses presented for colic between 2004 and 2014 were reviewed. Severity of sand accumulation was quantified by tracing and measuring a region of interest with a commercial software program. Breed, weight, amount of sand, presence of diarrhea at presentation, treatment, and the development of complications were recorded. RESULTS: Records from 153 horses were reviewed. The mean cross-sectional area of sand accumulation was 692.9 cm2 (median = 658.7 cm2 , 84.6-1780.7 cm2 ). Increased accumulation of gas on radiographs and abnormal transrectal examination findings were associated with an increased likelihood of surgery. The most common complication was the development of diarrhea (20.3%) with only 4 (2.6%) horses positive for Salmonella spp. Horses had a favorable prognosis, with 94.8% of horses treated medically and 94.7% of those treated surgically surviving to discharge. CONCLUSION: Increased accumulation of gas on radiographs and transrectal palpation of impaction or intestinal gas distension increase the likelihood of surgery. Both medical and surgical treatments carry a good prognosis. CLINICAL RELEVANCE: The sheer quantity of sand is not a factor when determining surgical intervention. Attention should be paid to the presence of increased gas accumulation on rectal or radiographic examination.

A novel ultrasonographic assisted technique for desmotomy of the palmar/plantar annular ligament in horses.

OBJECTIVES: To describe an ultrasound assisted technique for desmotomy of the palmar/plantar annular ligament (PAL), determine its efficacy and intraoperative complications. STUDY DESIGN: Cadaveric and in vivo study. ANIMALS: Cadaveric limbs (n = 12), adult horses (n = 4), and clinical cases (n = 2). METHODS: Ultrasound assisted desmotomy of the palmar/plantar annular ligament (UAD-PAL) was performed in cadaveric limbs and in standing horses with the operated limb placed in a distal limb splint. The procedure was performed under general anesthesia and was followed by tenoscopic examination in 2 clinical cases. A hook knife was developed for the procedure. Complete transection was assessed by postmortem dissection (10 forelimbs, 10 hindlimbs) and tenoscopic examination (1 forelimb, 1 hindlimb). Thickness of PAL, surgery time, other intraoperative parameters and complications associated with the procedure were recorded. RESULTS: Complete PAL transection was accomplished in 20/22 limbs. No iatrogenic damage to adjacent intrathecal structures was identified in any case. The instrument was correctly positioned on the first attempt in 19/22 cases. The most common intraoperative complication was inadvertent subcutaneous placement of the instrument (n = 2). Significant thickening of the PAL (3 mm) was present in 1/2 limbs in which complete transection was not achieved. CONCLUSIONS: UAD-PAL with the custom-made hook knife was effective at transecting the PAL with minimal intraoperative complications. The procedure can be performed in standing sedated horses. Another method should be considered in horses with thickened PAL.

Comparison of clinical findings and short-term survival between horses with intestinal entrapment in the gastrosplenic ligament and horses with intestinal entrapment in the epiploic foramen.

OBJECTIVE To compare clinical findings and short-term outcome for horses with intestinal entrapment in the gastrosplenic ligament (GLE) with those of horses with intestinal entrapment in the epiploic foramen (EFE). DESIGN Retrospective case-control study. ANIMALS 43 horses with GLE (cases) and 73 horses with EFE (controls). PROCEDURES Medical records of horses examined because of colic at a veterinary teaching hospital between 1992 and 2012 were reviewed. Signalment was extracted from medical records for all horses with colic (colic population), and additional information regarding colic history, clinical findings, treatments, and outcome was extracted from the records of horses in which GLE or EFE was diagnosed during surgery or necropsy. Signalment was compared between the colic population and the case and control populations. Clinical findings and short-term outcome were compared between the cases and controls. RESULTS The proportions of middle-aged horses and geldings in both the case and control groups were greater than those in the colic population. Mean heart rate and blood and peritoneal fluid lactate concentrations in horses with EFE were significantly greater than those for horses with GLE. The proportion of horses that underwent surgery and were discharged from the hospital (short-term survival rate) did not differ between the GLE (22/25 [88%]) and EFE (29/34 [85%]) groups. CONCLUSIONS AND CLINICAL RELEVANCE Compared with the colic population, results suggested middle-aged geldings might be predisposed to GLE and EFE. The short-term survival rate was similar between the GLE and EFE groups even though horses with EFE had more severe systemic derangements than did horses with GLE.

Use of an Absorbable Urethral Stent for the Management of a Urethral Stricture in a Stallion.

OBJECTIVE: To describe the successful management of a urethral stricture with an absorbable stent in a stallion. STUDY DESIGN: Clinical report. ANIMALS: Stallion with a urethral stricture. RESULTS: A 12-year-old Thoroughbred breeding stallion was evaluated for acute onset of colic. Uroperitoneum because of presumptive urinary bladder rupture, with urethral obstruction by a urethrolith, was diagnosed. The uroperitoneum was treated conservatively. The urethrolith was removed through a perineal urethrotomy. Approximately 15 weeks after urethrolith removal, the stallion presented with a urethral stricture. The stricture was unsuccessfully treated with an indwelling urinary catheter and 4 attempts at balloon dilation. Eight weeks after diagnosis of stricture, an absorbable polydioxanone (20 mm × 80 mm) urethral stent was implanted under percutaneous, ultrasound guidance. Urethroscopy was performed at 70, 155, and 230 days after stent placement and the endoscope passed through the affected site without complication. Urethroscopy at 155 days showed the stent had been reabsorbed. Follow-up 20 months after stent placement reports the stallion was able to void a normal urine stream. CONCLUSIONS: Absorbable urethral stent placement was a feasible treatment for urethral stricture in this stallion.

Sialoendoscopy as a treatment for an obstructed mandibular salivary duct in a horse.

A 14-year-old Quarter Horse was examined for a draining tract of 8 months' duration on the right mandible that was non-responsive to antibiotic therapy and surgical therapy. Further investigation and subsequent treatment with sialoendoscopy and ultrasonography were performed to relieve an obstruction of plant awns in the mandibular salivary duct.

Sialo-endoscopie comme traitement pour un canal salivaire mandibulaire bloqué chez un cheval. Un cheval Quarter Horse âgé de 14 ans a été examiné pour une fistule purulente d'une durée de 8 mois à la mandibule droite qui ne répondait pas à la thérapie antibiotique et à la thérapie chirurgicale. De nouvelles investigations et le traitement subséquent à l'aide de la sialo-endoscopie et de l'échographie ont été réalisés pour éliminer un blocage du canal salivaire mandibulaire par des barbes de plantes.(Traduit par Isabelle Vallières).

Pharmacokinetics of a combination of amikacin sulfate and penicillin G sodium for intravenous regional limb perfusion in adult horses.

The aim of this study was to determine the pharmacokinetics of amikacin and penicillin G sodium when administered in combination as an intravenous regional limb perfusion (IVRLP) to horses. Seven healthy adult horses underwent an IVRLP in the cephalic vein with 2 g of amikacin sulfate and 10 mill IU of penicillin G sodium diluted to 60 mL in 0.9% saline. A pneumatic tourniquet set at 450 mmHg was left in place for 30 min. Synovial fluid was collected from the metacarpophalangeal joint 35 min and 2, 6, 12, and 24 h after infusion of the antimicrobials. Concentrations of amikacin and penicillin in synovial fluid were quantitated by liquid chromatography tandem-mass spectrometry analysis. Therapeutic concentrations of amikacin and penicillin for equine-susceptible pathogens were achieved in the synovial fluid. Maximum synovial concentrations (Cmax) (mean ± SE) for amikacin and penicillin were 132 ± 33 µg/mL and 8474 ± 5710 ng/mL, respectively. Only 3 horses had detectable levels of penicillin at 6 h and 1 at the 12 h sample. The combination of amikacin with penicillin G sodium via IVDLP resulted in reported therapeutic concentrations of both antibiotics in the synovial fluid. The Cmax:MIC (minimum inhibitory concentration) ratio for amikacin was 8:1 and Time > MIC for penicillin was 6 h. At 24 h, the mean concentration of amikacin was still above 4 µg/mL. Terminal elimination rate constants (T1/2 lambdaz) were 13.6 h and 2.8 h for amikacin and penicillin, respectively. The use of IVDLP with penicillin may therefore not be practical as rapid clearance of penicillin from the synovial fluid requires frequent perfusions to maintain acceptable therapeutic concentrations.

L'objectif de la présente étude était de déterminer la pharmacocinétique de l'amikacine et de la pénicilline G sodique lorsqu'administrées en combinaison par perfusion intraveineuse régionale d'un membre (PIVRM) à des chevaux. Sept chevaux adultes ont reçu une PIVRM dans la veine céphalique avec 2 g de sulfate d'amikacine et 10 millions d'UI de pénicilline G sodique dilués dans 60 mL de saline 0,9 %. Un tourniquet pneumatique réglé à 450 mmHg a été laissé en place pour 30 min. Du liquide synovial a été récolté de l'articulation métacarpo-phalangienne 35 min, 2, 6, 12, et 24 h après l'infusion des antimicrobiens. Les concentrations d'amikacine et de pénicilline dans le liquide synovial furent mesurées par spectrométrie de masse en tandem avec la chromatographie en phase liquide. Les concentrations thérapeutiques d'amikacine et de pénicilline pour des agents pathogènes équins sensibles ont été atteintes dans le liquide synovial. Les concentrations synoviales maximales (Cmax) [moyenne ± écart-type (EC)] pour l'amikacine et la pénicilline étaient de 132 ± 33 µg/mL et 8474 ± 5710 ng/mL, respectivement. Seulement 3 chevaux avaient des quantités détectables de pénicilline à 6 h et un seul pour l'échantillon de 12 h. La combinaison d'amikacine et de pénicilline G sodique via PIVRM a permis de rapporter des concentrations thérapeutiques des deux antibiotiques dans le liquide synovial. Le ratio Cmax-CMI (concentration minimale inhibitrice) pour l'amikacine était de 8:1 et la période de Temps > CMI pour la pénicilline était de 6 h. À 24 h, la concentration moyenne d'amikacine était toujours supérieure à 4 µg/mL. Les constantes du taux d'élimination terminal (T1/2 lambdaz) étaient 13,6 h et 2,8 h pour l'amikacine et la pénicilline, respectivement. L'utilisation de PIVRM avec la pénicilline ne serait ainsi pas pratique étant donné que la clairance rapide de la pénicilline à partir du liquide synovial requière des perfusions fréquentes pour maintenir des concentrations thérapeutiques acceptables.(Traduit par Docteur Serge Messier).

Use of a laparoscopic specimen retrieval pouch to facilitate removal of intact or fragmented cystic calculi from standing sedated horses: 8 cases (2012-2015).

OBJECTIVE To evaluate the use of a laparoscopic specimen retrieval pouch for removal of intact or fragmented cystic calculi from standing horses. DESIGN Retrospective case series. ANIMALS 8 horses (5 geldings and 3 mares) with cystic calculi. PROCEDURES Physical examination and cystoscopic, ultrasonographic, and hematologic evaluations of urinary tract function were performed for each horse. A diagnosis of cystic calculus was made on the basis of results of cystoscopy and ultrasonography. Concurrent urolithiasis or other urinary tract abnormalities identified during preoperative evaluation were recorded. Horses were sedated and placed in standing stocks, and the perineum was aseptically prepared. Direct access to the urinary bladder was gained in geldings via perineal urethrotomy or in mares by a transurethral approach. Calculi were visualized endoscopically, manipulated into the retrieval pouch, and removed intact or fragmented (for larger calculi). RESULTS For 4 geldings and 1 mare, fragmentation was necessary to facilitate calculus removal. Mean duration of surgery was 125 minutes, and trauma to the urinary bladder and urethra was limited to areas of hyperemia and submucosal petechiation. No postoperative complications were encountered for any horse. When lithotripsy was required, the retrieval pouch provided an effective means of stabilizing calculi and containing the fragments for removal. CONCLUSIONS AND CLINICAL RELEVANCE Use of the laparoscopic specimen retrieval pouch was an effective, minimally traumatic method for retrieving cystic calculi from standing horses. The pouch protected the urinary bladder and urethra from trauma during calculus removal and allowed for stabilization, containment, and fragmentation of calculi when necessary.

Identification, management and outcome of postoperative hemoperitoneum in 23 horses after emergency exploratory celiotomy for gastrointestinal disease.

OBJECTIVE: To investigate postoperative hemoperitoneum in a population of horses that had surgery for colic. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n = 23). METHODS: Preoperative, intraoperative, and postoperative information was obtained from medical records (1985-2012) of horses with postoperative hemoperitoneum after emergency exploratory celiotomy. Pre-existing hemoperitoneum during surgery and nonsurgical hemoperitoneum were excluded. RESULTS: Of 4520 horses that had emergency exploratory celiotomy for gastrointestinal disease, 23 horses met inclusion criteria; an incidence of 0.5%. Horse signalment approximated the colic population, although Thoroughbreds were significantly overrepresented. Hemoperitoneum was significantly associated with intestinal resection. Postoperative hemoperitoneum was recognized a mean (± SD) of 1.0 ± 0.7 days after surgery and associated with tachycardia, decreasing hematocrit, incisional drainage, or ultrasonographic identification of swirling, echogenic abdominal fluid. Primary treatments included intravenous fluid therapy (n = 23), colloid support (20), blood transfusion (13), and antifibrinolytic agents (11). Fifteen horses (65%) survived to discharge, which was associated with admission lactate and days of hospitalization. CONCLUSIONS: Postoperative hemoperitoneum is a rare complication of exploratory celiotomy in horses that should be considered when there are signs of abdominal discomfort and declining hematocrit in the early postoperative period. Prognosis is guarded because of potential sequelae of septic peritonitis and adhesion formation.

Evaluation of 3 handheld portable analyzers for measurement of L-lactate concentrations in blood and peritoneal fluid of horses with colic.

OBJECTIVE: To compare 3 portable handheld analyzers with a bench top blood gas analyzer for measurement of blood and peritoneal fluid L-lactate concentrations in horses admitted with signs of colic. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Blood and peritoneal fluid from horses with colic. METHODS: L-lactate concentrations in heparinized blood and peritoneal fluid were measured serially on 10 occasions to evaluate repeatability of the portable analyzers. Blood and peritoneal fluid L-lactate concentrations were simultaneously evaluated by a bench top and 3 portable analyzers and the results compared by intraclass correlation coefficients and Bland Altman plots. L-Lactate concentrations in a subgroup of peritoneal fluid samples were evaluated by a chromogenic laboratory assay and compared with the bench top and the handheld analyzers. RESULTS: Portable lactate analyzers had good intra-analyzer reliability for peritoneal fluid. Two portable analyzers had poor intra-analyzer reliability for mid concentrations of L-lactate in blood. L-lactate measurements from portable analyzers were closer to the bench top analyzer at low concentrations of L-lactate than at higher concentrations. Compared with the bench top analyzer, the Lactate Pro and Lactate Plus have the highest intraclass correlation coefficient and the smallest bias for peritoneal fluid and blood L-lactate, respectively. The bench top analyzer and the Lactate Pro had the highest level of agreement for peritoneal fluid compared with the chromogenic assay. CONCLUSIONS: Although portable analyzers are alternatives for the measurement of L-lactate concentration in field situations, clinicians need to be aware of the variable results between analyzers, especially when extrapolating means or cutoff values from studies using different lactate analyzers.