Critical Care of the Colic Patient: Monitoring, Fluid Therapy, and More.

A successful outcome to management of the critical colic patient is highly dependent on how the patient is monitored and treated, particularly, in the perioperative period. In this article, we will provide an update on monitoring techniques, advances in fluid therapy, nutrition management and pharmacotherapeutic agents, inclusive of pain monitoring and management, prokinetics, and management of systemic inflammatory response syndrome and the hypercoagulable state.

Successful surgical removal of a pheochromocytoma in a mare via trans-costal approach.

BACKGROUND: Pheochromocytomas have been previously reported in horses, but successful antemortem diagnosis and surgical removal without recurrence of clinical signs have not been described. OBJECTIVE: To report the clinical presentation, diagnostic evaluation, surgical technique, anaesthetic management and post-operative care of a mare diagnosed with pheochromocytoma. STUDY DESIGN: Clinical case report. METHODS: An 18-year-old Quarter Horse mare presented for recurrent episodes of colic, profuse sweating, muscle fasciculations and agitation over a 2-month period. Clinical, clinicopathologic and ultrasonographic (transcutaneous, transrectal) abnormalities were consistent with a unilateral left-sided adrenal mass. Surgical removal of the mass was performed via a trans-costal approach with removal of the 18th rib and retraction of the left kidney to improve exposure. Associated vasculature was ligated, and the adrenal mass was removed and submitted for histopathology and immunohistochemistry. RESULTS: A trans-costal surgical approach provided excellent visualisation of the adrenal mass and allowed for identification and ligation of associated vessels. Total surgical and anaesthesia time were 86 and 114 min, respectively. Several intraoperative (hypertension, tachycardia) and post-operative (colic with tachycardia, tachypnea, large colon pelvic flexure impaction and nasogastric reflux) complications were encountered and managed successfully. Immunohistochemistry demonstrated positive labelling for synaptophysin and chromogranin A, confirming diagnosis of pheochromocytoma. The mare had recovered well at 6-week recheck post-operatively and returned to training at 6 months post-operatively. No further clinical signs consistent with pheochromocytoma have been observed following removal. CONCLUSIONS: The trans-costal approach allowed for surgical removal of a pheochromocytoma in a mare. Surgical removal of adrenal masses in horses may be associated with complications yet was successfully performed without subsequent recurrence of clinical signs associated with tumour presence and return to athletic use in this mare.

Transcutaneous Detection of Intramural Microchips for Tracking the Migration of the Equine Large Colon: A Pilot Study.

Colic remains the number one cause of mortality in horses, and large colon displacement including colonic volvulus is one of the leading causes for equine hospitalization and surgery. Currently, there is not an adequate model to study the pathophysiology of this condition. The objective of this proof-of-concept study was to determine if subserosal implantation of bioinert microchips in the large intestine would be detectable by a RFID (radio-frequency identification) receiver when the implanted microchips were adjacent to the body wall, thus identifying the location of the colon within the abdomen. A horse with no history of gastrointestinal disease underwent a ventral midline celiotomy to implant twelve bioinert microchips into the subserosa at predetermined locations within the large colon and cecum. A RFID scanner was used to monitor the location of the colon via transcutaneous identification 1-3 times daily for a one-month period. Following humane euthanasia, a postmortem examination of the horse was performed to assess microchip implantation sites for migration and histologic assessment. Eleven out of the 12 implanted microchips were successfully identified transcutaneously at occurrences as high as 100%. Odds ratios were calculated for the likelihood of identifying each chip in a location different from its most common location. Microchips implanted into the subserosa of the equine large colon can be used as a means of identifying the approximate location of the equine large colon via transcutaneous identification with an RFID scanner.

Multi-Institutional Retrospective Case-Control Study Evaluating Clinical Outcomes of Foals with Small Intestinal Strangulating Obstruction: 2000-2020.

Lower survival has been reported in foals than adults with small intestinal strangulating obstruction (SISO), but age-dependent outcomes have not been examined directly. Hospital records were collected from five US academic referral hospitals. It was hypothesized that foals would exhibit lower survival than case-matched adults. Foal cases 6-months-of-age or younger, and adult cases between 2- and 20-years-of-age were collected. Data revealed 24 of 25 (96.0%) foals and 66 of 75 (88.0%) adults that were recovered from surgery for SISO survived to hospital discharge. Sixteen of the total 41 (39.0%) foals studied were euthanized intraoperatively, whereas 30 of 105 (28.6%) adults were euthanized intraoperatively. Common lesions in foals that were recovered from surgery were volvulus (n = 13) and intussusception (n = 5), whereas common lesions in adults were volvulus (n = 25) and strangulating lipoma (n = 23). This study was limited by incomplete medical records, relatively small sample size, and lack of long-term follow-up. Unexpectedly, short-term survival tended to be higher in foals than adults and may have been partly driven by case selection prior to referral or surgery or decision-making intraoperatively. More optimism toward surgical treatment of foals with SISO may be warranted.

Inter-Institutional Collaboration for the Development of a Local Peer Observation Process to Enhance Teaching.

Local peer observation of teaching is considered an important mechanism for instructors to improve the quality and effectiveness of their teaching, but there is an absence of uniformity to establish a best practice for this process in veterinary curricula. The Regional Teaching Academy (RTA) of the Consortium of Western Colleges of Veterinary Medicine is comprised of educational advocates from five western veterinary colleges with a common goal of enhancing the quality and effectiveness of education in veterinary medical curricula. Members of the RTA recognized this deficit in best practices for local peer observation (LPO) and formed a working group called "Local Peer Observation of Teaching." The goal was to meet a critical need for the enhancement of individual teaching skills by using a scholarly approach to develop robust methods for peer observation of teaching. Two rubric-based instruments were developed: one for large-group/didactic settings, and the second for small-group/clinical settings. Each is accompanied by pre- and post-observation worksheets which are considered instrumental to success. Results of a qualitative survey of instrument users' experiences are shared. Both observers and observees view the experiential learning from faculty peer colleagues very positively and the meaningful feedback is appreciated and incorporated by observees. Suggestions for implementation of the peer observation process are discussed, considering strengths and challenges. The purpose of this article is to describe in depth, the development process and output of the efforts of the Local Peer Observation of Teaching working group as a potential best practice guideline for peer observation.

Geographic Disparities in Clinical Characteristics of Duodenitis-Proximal Jejunitis in Horses in the United States.

Duodenitis-proximal jejunitis (DPJ) is an idiopathic and potentially fatal disease of horses characterized by abdominal pain, proximal intestinal inflammation, and subsequent gastric and small intestinal fluid accumulation. Although this disease is known to be costly and life threatening in the equine industry, the severity of clinical signs can vary widely, and an exact etiology has yet to be elucidated. This study looked to identify differences in clinical parameters of horses with DPJ between geographic regions in an effort to corroborate anecdotal reports and support theories of differing etiologies. Case records were compared from veterinary academic referral hospitals in three different geographic locations in the United States to determine if significant differences in clinical, clinicopathologic, and prognostic characteristics exist among horses with DPJ. Clinical measurements on presentation that were significantly different between regions included heart rate, peritoneal total protein, albumin, anion gap, aspartate aminotransferase, gamma-glutamyl transferase, sodium, chloride, potassium, and creatinine. Duration of hospitalization and maximum body temperature while hospitalized were also different between regions. There were no significant differences in peritoneal cell count, total white blood cell count, neutrophil count, band neutrophils, calcium, total plasma protein, temperature on presentation, duration of reflux, total reflux volume, or age between hospitals. The mortality rates between hospitals were not significantly different. Increased severity of clinical signs and biochemical abnormalities were identified in the Southeastern United States hospital compared with the Northeastern and Western hospitals. A prospective, multicenter case-control study could identify risk factors contributing toward regional differences in this disease in the future.

Evaluation of Fecal Sand Clearance in Horses With Naturally Acquired Colonic Sand Accumulation With a Product Containing Probiotics, Prebiotics, and Psyllium.

Consumption of sand and dirt in horses can cause chronic diarrhea and colic because of irritation and obstruction of the gastrointestinal tract of horses. Prevention has primarily focused on changes in management to reduce the intake of sand and feeding of psyllium products. The purpose of this study was to evaluate the efficacy of a product containing probiotics, prebiotics, and psyllium in the clearance of colonic sand in horses with naturally acquired sand accumulation using a randomized, placebo-controlled, blinded clinical trial format. After identification of 10 horses with sand accumulation as determined by both auscultation and abdominal radiography, quantitative assessment of changes in colonic sand content in response to management changes combined with treatment with the probiotic/psyllium product or no treatment was assessed by blinded observers. Fecal sand output was monitored in both groups via sand sedimentation analysis of fecal samples every 3 days for 35 days and with pre- and post-treatment abdominal radiography. There was a significant reduction in sand accumulation in both treatment and control groups, but there were no significant differences between treatment and control groups in clearance of colonic sand as measured by both fecal sand sedimentation and quantitative radiography.

Combined tube cystostomy and urethrotomy for the treatment of urethral obstruction due to urolithiasis in goats.

OBJECTIVE: To describe the treatment of goats with urethral obstruction secondary to urolithiasis by combining tube cystostomy and urethrotomy. ANIMALS: Eight male goats. STUDY DESIGN: Short case series. METHODS: Medical records (September 2012-September 2017) of male goats treated for obstruction secondary to urolithiasis with tube cystostomy and urethrotomy were reviewed. Data collected included signalment, history, physical examination findings, diagnostic results, perioperative treatments, operative details, hospitalization duration, intraoperative and postoperative complications, urolith analysis, and time to restoration of urethral patency. Long-term follow-up (>12 months) was obtained by email or telephone interviews of owners or by clinical examination. RESULTS: Seven of eight goats were castrated males of various of breeds. All goats were tachycardic with urethral pulsation at admission. Uroliths were composed of calcium carbonate in four goats and silica in one goat. All goats regained urethral patency during hospitalization, and all were discharged alive from the hospital. Seven goats were alive at long-term follow-up. Postoperative complications included persistent urethral obstruction requiring a second urethrotomy 2 days postoperatively, premature dislodgement of the bladder catheter and jejunal obstruction secondary to adhesions, and recurrence of obstructive urolithiasis within the proximal perineal urethra requiring a second surgery 8 months later (1 each). Long-term outcome was good, with urethral patency beyond 12 months in six of eight goats. CONCLUSION: Combining tube cystostomy and urethrotomy restored urethral patency in goats with urethral obstruction from uroliths. Although none of the complications seemed directly related to the urethrotomy, formation of abdominal adhesions and recurrence of urolithiasis affected long-term outcomes. CLINICAL SIGNIFICANCE: Uroliths that do not dissolve in acidic urine may be more frequent in some practices. The combined approach of tube cystostomy and urethrotomy appears to successfully restore urethral patency with promising long-term outcomes.

Equine urinary N-acetyl-ß-D-glucosaminidase assay validation and correlation with other markers of kidney injury.

Detection of equine acute kidney injury (AKI) is hindered by limited markers of early renal damage in horses. N-acetyl-ß-D-glucosaminidase (NAG), a lysosomal enzyme in renal tubular epithelium released into urine during tubular insult, has shown promise for early identification of AKI in humans and other species. We validated an assay for NAG in equine urine and measured urinary NAG in 7 azotemic and 7 non-azotemic client-owned adult horses. The enzymatic NAG assay was validated using within- and between-run coefficients of variation (CVs), recovery following standard addition, and linearity of dilution. Intra- and inter-run CVs (21% and 3.2%, respectively), average recovery following standard addition (99-109%), and linearity under serial dilution (R2 = 0.997) were satisfactory. Urine NAG index was significantly correlated with urinary fractional excretion of sodium (FENa; ρ = 0.76, p < 0.001) and plasma creatinine (ρ = 0.74, p = 0.001). Median urine NAG indices were higher in azotemic horses (p = 0.006), in horses with increased urinary FENa (p = 0.006), and in horses with increased urine gamma-glutamyl transferase index (p = 0.032). Urine NAG can be measured in horses and shows positive correlation with 2 current renal biomarkers. Additional work is needed to establish normal equine reference intervals and characterize the increase of urine NAG index in horses in relation to tubular injury.

Equine Fecal Microbiota Changes Associated With Anthelmintic Administration.

The gastrointestinal microbiota (GIM) plays an essential role in maintaining intestinal homeostasis with disruptions having profound effects on the wellbeing of the host animal. Parasitic infection is a long-standing issue for the equine industry, and the use of anthelmintic drugs for parasite control has long been standard practice. The impact of anthelmintic treatment on the GIM in healthy horses is not well known. This study evaluated the hypothesis that anthelmintic administration will alter the equine fecal microbiota in horses without an observed helminth infection. Ten horses were treated with a single dose of QUEST PLUS (active ingredients: Moxidectin and Praziquantel) (Zoetis), and fecal samples were collected before and after treatment. Amplicon sequencing data were quality filtered, processed, and analyzed using QIIME2. Anthelmintic treatment corresponded with a small but significant decrease in alpha diversity (P-value < .05). Analysis of taxonomic abundances before and after treatment with DESeq2 identified 21 features that were significantly different after treatment (Padj-value < .05). Differences in beta diversity associated with treatment were not significant and potentially suggest factors unique to the individual may play an essential role in the specific responses observed. Overall, the present study does not indicate a broad, large-scale impact on the GIM after anthelmintic treatment. The results do, however, suggest the potential of individualized responses that are based instead on host factors. Identification of these factors and investigation of their impact on the host/microbiota relationship will contribute significantly to our understanding of the role of the microbiome in horse health.

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

Reactive mesothelial hyperplasia associated with chronic peritonitis in a 20-year-old Quarter horse.

A 20-year-old gelding was diagnosed with peritonitis and severe reactive mesothelial hyperplasia. Exploratory laparotomy findings were suggestive of a neoplastic etiology; however, additional diagnostics ruled this out and the horse made a full recovery. This report demonstrates the difficulty and value of differentiating between reactive and neoplastic mesothelial processes.

Hyperplasie mésothéliale réactive associée à une péritonite aiguë chez un cheval Quarter horse âgé de 20 ans. Une péritonite et l'hyperplasie mésothéliale réactive grave ont été diagnostiquées chez un hongre âgé de 20 ans. Les résultats d'une laparatomie exploratoire ont suggéré une étiologie néoplasique. Cependant, des diagnostics additionnels ont éliminé cette possibilité et le cheval s'est complètement rétabli. Ce rapport démontre la difficulté et la pertinence de différencier entre les processus mésothéliaux réactif et néoplasique.(Traduit par Isabelle Vallières).

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.

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.

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.

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.

Rib fracture in a horse during an endurance race.

We describe a fatal case, in which a horse suffered a fall and as a consequence, rib fractures. Diagnosis was made postmortem and the horse died without showing clear signs of respiratory dysfunction. The retrospective reports of injuries can be important to reduce these traumatic events and to avoid fatalities.

Measurement of urinary F2-isoprostanes as markers of in vivo lipid peroxidation: a comparison of enzyme immunoassays with gas chromatography-mass spectrometry in domestic animal species.

F(2)-isoprostanes are useful markers for assessing oxidant injury; however, the validity of measuring urinary 15-F(2t)-isoprostane concentration by enzyme-linked immunosorbent assay (ELISA) has not been evaluated in veterinary species. The current study assesses the agreement between 2 commercially available urinary isoprostane kits and gas chromatography and negative ion chemical ionization-mass spectrometry (GC/NICI-MS). The results indicate that only feline urinary isoprostane measurement by glucuronidase (GL)-ELISA has acceptable agreement with GC/NICI-MS. Urinary isoprostane concentration was highly variable in critically ill animals, but there were too many variations between healthy and critically ill animals to draw meaningful conclusions. Currently, GC/NICI-MS is the only method that can be recommended for the assessment of urinary isoprostanes in dogs, cattle, and horses. Feline urinary isoprostanes can be assessed by GL-ELISA, but caution is still warranted when comparing data from manuscripts using different methods given the relatively low Spearman rank correlation coefficient. Future studies may require large sample sizes or focused inclusion criteria to account for variability in isoprostane concentration.