Diana M. Hassel

Adsorptive effects of di-tri-octahedral smectite on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies

OBJECTIVE To determine the adsorptive capability of di-tri-octahedral smectite (DTOS) on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies. SAMPLE POPULATION 3 C perfringens exotoxins and 9 colostral samples. PROCEDURES Alpha, beta, and beta-2 exotoxins were individually co-incubated with serial dilutions of DTOS or bismuth subsalicylate, and the amount of toxin remaining after incubation was determined via toxin-specific ELISAs. Colostral samples from healthy mares were individually co-incubated with serial dilutions of DTOS, and colostral IgG concentrations were determined via single radial immunodiffusion assay. RESULTS Di-tri-octahedral smectite decreased the amount of each C perfringens exotoxin in co-incubated samples in a dose-dependent manner and was more effective than bismuth subsalicylate at reducing exotoxins in vitro. Decreases in the concentration of IgG were detected in samples of colostrum that were combined with DTOS at 1:4 through 1:16 dilutions, whereas no significant decrease was evident with DTOS at the 1:32 dilution. CONCLUSIONS AND CLINICAL RELEVANCE Di-tri-octahedral smectite effectively adsorbed C perfringens exotoxins in vitro and had a dose-dependent effect on the availability of equine colostral antibodies. Results suggested that DTOS may be an appropriate adjunctive treatment in the management of neonatal clostridiosis in horses. In vivo studies are necessary to fully assess the clinical efficacy of DTOS treatment.

In vitro comparison of V‐Loc™ versus Biosyn™ in a one‐layer end‐to‐end anastomosis of equine jejunum

OBJECTIVE To compare a unidirectional barbed suture (V-Loc™) to its suture material equivalent (Biosyn™) in a single-layer end-to-end anastomosis of equine jejunum. STUDY DESIGN Experimental in vitro study. ANIMALS Jejunal sections from adult horses (n = 5) without gastrointestinal disease. METHODS Jejunal end-to-end anastomoses (n = 9) were performed for each group (V-Loc™, Biosyn™) with a continuous Lembert pattern with an interruption every 120°. Anastomosis construction time, luminal diameter, and number of suture bites were recorded. Anastomosis constructs were distended with fluid at 1 L/min until failure. Location and intraluminal pressure at failure were recorded and all measurements were compared between groups. RESULTS V-Loc™ anastomoses were significantly faster to perform (13.1 ± 0.35 minutes) when compared to the Biosyn™ group (15.6 ± 0.72 minutes; P = .0004). No differences were observed for anastomotic index or number of suture bites. V-Loc™ anastomosis constructs had a significantly decreased bursting pressure (160 ± 11.6 mmHg) compared to Biosyn™ constructs (184 ± 16.9 mmHg; P = .01). CONCLUSIONS V-Loc™ allowed faster construction time and did not cause a decreased anastomosis luminal diameter when compared with Biosyn™. V-Loc™ had a decreased bursting strength compared with Biosyn™, albeit well above pathologic pressures encountered clinically. Use of V-Loc™ may be beneficial for decreasing the amount of exposed suture material because of the absence of knots after construction and has the potential to result in decreased adhesions.Objective To compare a unidirectional barbed suture (V-Loc™) to its suture material equivalent (Biosyn™) in a single-layer end-to-end anastomosis of equine jejunum. Study Design Experimental in vitro study. Animals Jejunal sections from adult horses (n = 5) without gastrointestinal disease. Methods Jejunal end-to-end anastomoses (n = 9) were performed for each group (V-Loc™, Biosyn™) with a continuous Lembert pattern with an interruption every 120°. Anastomosis construction time, luminal diameter, and number of suture bites were recorded. Anastomosis constructs were distended with fluid at 1 L/min until failure. Location and intraluminal pressure at failure were recorded and all measurements were compared between groups. Results V-Loc™ anastomoses were significantly faster to perform (13.1 ± 0.35 minutes) when compared to the Biosyn™ group (15.6 ± 0.72 minutes; P = .0004). No differences were observed for anastomotic index or number of suture bites. V-Loc™ anastomosis constructs had a significantly decreased bursting pressure (160 ± 11.6 mmHg) compared to Biosyn™ constructs (184 ± 16.9 mmHg; P = .01). Conclusions V-Loc™ allowed faster construction time and did not cause a decreased anastomosis luminal diameter when compared with Biosyn™. V-Loc™ had a decreased bursting strength compared with Biosyn™, albeit well above pathologic pressures encountered clinically. Use of V-Loc™ may be beneficial for decreasing the amount of exposed suture material because of the absence of knots after construction and has the potential to result in decreased adhesions.

Di-tri-octahedral smectite for the prevention of post-operative diarrhea in equids with surgical disease of the large intestine: results of a randomized clinical trial.

The aim of this study was to evaluate the effects of a commercially available di-tri-octahedral (DTO) smectite product on clinical signs and prevalence of post-operative diarrhea in horses with colic associated with disease of the large intestine. Sixty-seven horses with surgical disease of the large intestine were randomly assigned to be treated with DTO smectite (n=37; 0.5 kg via nasogastric intubation every 24 h for 3 days post-operatively) or a placebo (n=30). The effect of treatment on fecal scores and clinical and hematological parameters, including heart rate, mucous membrane color, temperature, total white blood cell count, total neutrophil count and total plasma protein values, were determined. Horses treated with DTO smectite had a significant reduction in the prevalence of post-operative diarrhea (10.8%), compared with controls (41.4%). A significant improvement in mucous membrane color was observed 72 h post-operatively in horses receiving treatment, compared with placebo. Administration of DTO smectite to colic patients with disease of the large intestine reduced the occurrence of diarrhea in the early post-operative period.

Colic: nonsurgical complications.

Colic is a serious disease of the horse and may require surgical correction. Postoperative complications may result in an increase in short-term morbidity and mortality. Commonly encountered nonsurgical complications are detailed. Anticipation and timely treatment of common postoperative complications after colic surgery may improve overall survival.

Concentrations of serum amyloid A and plasma fibrinogen in horses undergoing emergency abdominal surgery

Objective To compare the perioperative response of serum amyloid A (SAA) to fibrinogen in horses requiring exploratory celiotomy for colic and to determine if SAA could be used to predict complications and outcome. Design Prospective observational clinical study. Setting University teaching hospital. Animals Eighteen horses undergoing exploratory celiotomy for colic. Inclusion criteria for the study included survival and anesthetic recovery from exploratory celiotomy, no history of surgery within the past year. Interventions Blood was obtained via jugular venipuncture before surgery (time 0) and at 24, 48, 72, and 96 hours after recovery from anesthesia. Measurements and Main Results Quantitative and semiquantitative fibrinogen, SAA, total nucleated cell counts, and total protein were evaluated at each time point. Multivariable linear regression was used to assess differences at each time point and after grouping horses according to duration of colic prior to surgery, strangulating surgical lesion or not, presence of systemic inflammatory response syndrome (SIRS) on admission, and postsurgical complications. Significant (P < 0.05) increases in SAA concentrations occurred in all cases after surgery compared to fibrinogen concentration, which only demonstrated a mild, clinically insignificant increase postsurgery. SAA concentrations were also significantly increased (P < 0.05) in cases identified with SIRS prior to surgery and postoperatively at 48 (P = 0.05) and 72 hours (P = 0.02) in horses that developed complications. Conclusions Measurement of SAA is a more sensitive indicator of inflammation than fibrinogen in the perioperative period of horses requiring exploratory celiotomy for colic. Serial measurement of SAA at 48, 72, and 96 hours after surgery may be helpful to determine risk of complications and guide postoperative management. Measurement of SAA on admission also allows for quantification of SIRS when it is detected clinically.OBJECTIVE To compare the perioperative response of serum amyloid A (SAA) to fibrinogen in horses requiring exploratory celiotomy for colic and to determine if SAA could be used to predict complications and outcome. DESIGN Prospective observational clinical study. SETTING University teaching hospital. ANIMALS Eighteen horses undergoing exploratory celiotomy for colic. Inclusion criteria for the study included survival and anesthetic recovery from exploratory celiotomy, no history of surgery within the past year. INTERVENTIONS Blood was obtained via jugular venipuncture before surgery (time 0) and at 24, 48, 72, and 96 hours after recovery from anesthesia. MEASUREMENTS AND MAIN RESULTS Quantitative and semiquantitative fibrinogen, SAA, total nucleated cell counts, and total protein were evaluated at each time point. Multivariable linear regression was used to assess differences at each time point and after grouping horses according to duration of colic prior to surgery, strangulating surgical lesion or not, presence of systemic inflammatory response syndrome (SIRS) on admission, and postsurgical complications. Significant (P < 0.05) increases in SAA concentrations occurred in all cases after surgery compared to fibrinogen concentration, which only demonstrated a mild, clinically insignificant increase postsurgery. SAA concentrations were also significantly increased (P < 0.05) in cases identified with SIRS prior to surgery and postoperatively at 48 (P = 0.05) and 72 hours (P = 0.02) in horses that developed complications. CONCLUSIONS Measurement of SAA is a more sensitive indicator of inflammation than fibrinogen in the perioperative period of horses requiring exploratory celiotomy for colic. Serial measurement of SAA at 48, 72, and 96 hours after surgery may be helpful to determine risk of complications and guide postoperative management. Measurement of SAA on admission also allows for quantification of SIRS when it is detected clinically.

Detection of calprotectin and apoptotic activity within the equine colon from horses with black walnut extract-induced laminitis

The black walnut extract (BWE) model of equine laminitis is associated with a systemic inflammatory response manifest by increased expression of inflammatory cytokines in the lungs and liver as well as the laminae. The specific role of the gastrointestinal tract in development of this response is unclear and is of utmost importance, as gastrointestinal disease and laminitis are intimately related. We investigated calprotectin expression and epithelial and endothelial apoptosis in the colon of horses exposed to orally administered BWE. Sections of colon from 19 horses including 7 controls not exposed to BWE, 6 horses at the developmental time-point of leukopenia (DTP) and 6 at the onset of Obel grade 1 laminitis (LAM) after BWE-administration were histologically examined. Immunohistochemical evaluation for calprotectin expression with MAC 387 antibody was performed along with assessment of epithelial and endothelial apoptosis with caspase-3 active antibody. Calprotectin expression and percentage of apoptotic cells were compared between controls and the two treatment groups and presence of a correlation between calprotectin expression and apoptosis was evaluated. Histological findings from BWE-treated horses included eosinophil and lymphocyte epitheliotropism. The DTP group had a higher (p<0.01) calprotectin score with respect to the control group, while there was no significant difference in percentage of epithelial and endothelial apoptotic cells between groups (p=0.08 and p=0.48 respectively). No significant correlation was found between calprotectin score and epithelial or endothelial apoptosis (p=0.69 and p=0.29 respectively). There is preliminary evidence that exposure of horses to BWE results in an early inflammatory response in the colon. Further studies are needed to characterize the nature of the colonic injury in BWE-exposed horses and the link to the development of laminitis.

Evaluation of the Colic in Horses: Decision for Referral

This article presents an overview of key factors that should alert the practitioner toward referral of a colic patient to a facility capable of surgical exploration or intensive medical management. Discussion includes a review of important aspects of colic history, signalment, physical examination findings, and diagnostic test results that indicate that a more serious medical or surgical condition exists, and advanced therapy is necessary.

Retrospective evaluation of the effect of intravenous fluid administration on development of postoperative reflux in horses with colic (2004-2012): 194 horses: Effect of fluids on postoperative reflux in horses

OBJECTIVE To evaluate the role of intravenous fluid volume and electrolyte supplementation on the development of postoperative reflux (POR) in horses undergoing celiotomy for colic. DESIGN Case-control study spanning 2004-2012 for horses undergoing celiotomy for colic. SETTING University teaching hospital. ANIMALS Sixty-seven client-owned horses >1 year of age with POR were each matched to 2 controls with similar surgical lesions that did not demonstrate POR. MEASUREMENTS AND MAIN RESULTS Survival was significantly lower in cases (65.7%) than controls (96.1%). Factors found to be associated with POR included decreased net fluid volume administered on day 1 postoperatively, increased age, and performing a resection and anastomosis. Mean time until onset of POR was 20.4 hours postoperatively. PCV was significantly higher immediately following surgery and at 24 hours postoperatively in horses that developed POR compared with matched controls. There was no association between electrolyte values at presentation or administration of potassium, calcium, or magnesium in the postoperative period and the subsequent development of reflux. CONCLUSIONS In the perioperative period, IV fluid volume overload and electrolyte abnormalities were not contributing factors in the development of POR in this population of surgical colic patients. Close postoperative monitoring with consideration and correction of pre- and postoperative fluid deficits is recommended.

Emergency and Critical Care

Ten years have passed since Dr Pamela Wilkins edited the last issue of Veterinary Clinics of North America: Equine Practice with the title, “Critical Care for All Ages.” Much has changed since that 2004 issue, and the field of equine critical care has continued to grow. This has been reflected in the slow, but steady growth of large animal specialists within the American College of Veterinary Emergency and Critical Care. These Veterinary Clinics of North America: Equine Practice articles provide a unique perspective from textbook information as they represent the most up-to-date information from leaders in the field of equine critical care medicine and surgery. The goal of this issue is not to present a comprehensive overview of equine critical care and emergency topics, but rather to touch on highlights of critical care medicine that have not been recently reviewed, while not excluding some key, clinically relevant topics that may be immediately applied in the field. Unique topics that may not be found elsewhere, such as gunshot wounds in the horse as well as more advanced topics pertaining to physiology, systemic inflammatory response syndrome, and hemorrhage and blood transfusions, are also covered. Among the more common conditions encountered by the emergency equine veterinarian are colic and neonatal triage. New information regarding pathogenesis, diagnostics, and therapy is available, so these and closely related topics are covered in depth. With the relatively recent RECOVER initiative pertaining primarily to small animal CPR, we felt it was appropriate to review the most recent and relevant techniques in equine CPR. This topic is further supported with a general review of triage in the neonatal foal as well as articles specific to management of neonatal sepsis and use and interpretation of blood lactate measurements in foals. Our colic coverage includes a beautifully illustrated review of abdominal ultrasound; an article dedicated to the diagnostic workup and making the decision for referral; a review of the latest evidence-based information on crystalloid and colloid therapy; the use of lactate as a diagnostic tool; and diagnosis, pathogenesis, and treatment of coagulopathies.