Non-strangulating intestinal infarction in horses in the UK: A review of 15 cases

The clinicopathological features of 15 horses diagnosed with non-strangulating intestinal infarction (NSII) based on identification of focal areas of intestinal necrosis without mesenteric strangulation were reviewed. The mean age at presentation was 16.3 years, median 13 years, and there was no age, sex, or breed predilection. The major presenting clinical signs included: acute colic ≤ 24 h duration in nine horses; diarrhoea, depression, and inappetence in four horses; and low-grade chronic or recurrent colic, depression, and inappetence in two horses. One horse presented with both acute colic and diarrhoea. Predisposing diseases included colitis or typhlocolitis in five horses and an initial strangulating small intestinal obstruction in three horses, but in seven horses no underlying or predisposing disease was identified. Four cases were managed medically and 11/15 were managed surgically. The most useful diagnostic test was exploratory celiotomy and the only successful treatment was complete resection of the necrotic intestine. Prognosis for survival was poor with a survival rate of only 1/15 (7%). Among the 15 horses, both single and multiple NSII lesions were seen, and they occurred in both the small intestine and large intestines. There was no evidence of Strongylus vulgaris infestation in any of the affected horses.     

Equine duodenal motility,assessed by ultrasonography,as a predictor of reflux and survival following colic surgery

Intestinal dysmotility following equine colic surgery contributes negatively to financial and prognostic outcomes. This study assessed duodenal contractility as a predictor of post-operative reflux and survival to discharge in horses following colic surgery. Duodenal contractility was assessed using daily transabdominal ultrasound examinations in 49 horses for up to 7 days (Day 1 scan performed between 6 and 36 h post-surgery and sequential daily scans performed between 08.00 and 20.00 h) following colic surgery (September 2014–April 2017). The duodenum was visualised ventral to the right kidney, and duodenal contractions were measured over 2 min. The signalment of each horse and surgical findings were noted. Outcomes were defined as horses that refluxed (>5 L/24 h beyond 24 h) or did not reflux post-operatively and those that were survivors or were nonsurvivors. A significant difference in duodenal contractions at Day 1 post-operatively was identified between horses that refluxed (n = 8) and those who did not reflux (n = 32; P = 0.013) but not between those who were nonsurvivors (n = 7) and survivors (n = 32; P = 0.113). Horses in the reflux group had reduced duodenal contractility comparatively. There were no significant differences in duodenal contractions in the sequential days after the Day 1 scan or between duodenal contractions and surgical findings. A significant association was identified between duodenal contractions and survivors (P = 0.039; odds ratio 1.88). The main study limitations were the single centre design with consequent small numbers of horses included. The study did not account for other factors that may contribute to alterations in motility such as drug administration or stages of re-feeding. This preliminary study indicates that Day 1 (6–36 h post-operatively) duodenal contractions may predict reflux (>5 L/24 h beyond 24 h) and that increased duodenal contractions are associated with survival. However, there was no clear distinction or cut-off between groups. Future studies with greater numbers of horses yielding better statistical power are required.     

Hemostatic abnormalities in equine colic

Hemostatic profiles were determined in 30 horses with clinical colic. Blood samples were obtained at the time of the animal's admission, and the following hemostatic tests were done: blood platelet count, plasma fibrinogen, plasma antithrombin, prothrombin time, partial thromboplastin time, thrombin time, protamine sulfate test for soluble fibrin monomer, and fibrin-fibrinogen degradation products. The patients were categorized in retrospect, according to the cause of the colic: group 1--colic associated with colitis and/or severe diarrhea, group 2--colic associated with torsion or obstruction of the intestine, and group 3--colic associated with impaction of the intestine or the presence of enteroliths. Of the 30 horses with colic, 28 had at least 1 abnormality in their coagulogram--the most frequent abnormalities being high plasma fibrinogen concentration, high circulating soluble fibrin monomer, or a long partial thromboplastin time or thrombin time. The horses in group 1 seemed to have the most severe coagulopathies, as indicated by the average number of demonstrable abnormalities. The horses in group 3 showed the fewest abnormalities--usually a high plasma concentrations of fibrinogen and/or soluble fibrin monomer. The results indicated that hemostatic abnormalities are not uncommon in horses with gastrointestinal disease and colic--the degree of severity depending to some extent on the cause of the colic.     

Intra-abdominal Pressure Screening of Horses With Colic

The objective of this study was to evaluate changes in intra-abdominal pressure (IAP) in horses with colic by associating the underlying etiologies with directly acquired IAP values and survival rate. This is a 2-year cohort study (2014–2016). Horses with clinical signs of colic were admitted to the veterinary teaching hospital during the period 2014–2016. Twenty-eight horses, of different breeds, males (stallions and geldings) and females, aged between 2 and 20 years, and weighing from 300 to 450 kg presenting with clinical signs of colic, were included in the study. IAP was directly acquired at the right flank (standing under sedation) and at the linea alba (supine position under general anesthesia). Twenty IAP measurements were recorded at end expiration for each recording site. IAP values >0.0 mmHg, obtained at the upper right flank in the standing position, were associated with surgical treatment (P < .05). In these cases, signs of colic were associated with strangulated obstructions of the large colon, and a greater likelihood of death as a result of colic (P < .001). Intra-abdominal pressure varied considerably in horses with colic, even for the same underlying etiologies. Horses with colic related to strangulating obstructions of the large intestine had IAP >.0 mmHg, at the upper right flank. These horses were also considerably more likely to require surgical intervention (P < .05) and death/euthanasia was more likely in this group of horses (P < .001).     

Survival and Complications After Large Colon Resection and End‐to‐End Anastomosis for Strangulating Large Colon Volvulus in Seventy‐Three Horses

Objective— To report complications and survival after large colon resection and end‐to‐end anastomosis in horses with strangulating large colon volvulus. Study Design— Retrospective case series. Animals— Horses (n=73) with strangulating large colon volvulus. Methods— Records (January 1995 to December 2005) of horses that had large colon resection and anastomosis for strangulating large colon volvulus were reviewed for complications. Follow‐up data were obtained by telephone questionnaire at least 1 year postoperatively. Cox proportional hazards model was used for multivariate association with survival time. Variables included admission date, age, temperature, heart rate, packed cell volume, total plasma protein concentration, white blood cell count, breed, and sex. Significance was set at P<.05. Results— The most common postoperative complication was diarrhea. None of the 9 variables of interest were significant for survival. Short‐term survival rate (to discharge) was 74%. Overall survival rates at 1, 2, and 3 years postoperatively were 67.8%, 66.0%, and 63.5%, respectively. Four horses died of colic in the first year after surgery. All horses surviving long‐term (>1 year) returned to their intended use (37 brood mares, 2 racehorses, and 1 show horse) with no chronic problems related to the surgical procedure. Conclusion— None of the variables examined were associated with survival. Outcomes were similar to other large studies of surgical colic in the horse. Self‐limiting diarrhea is common after large colon resection and the prognosis for survival after hospital discharge is favorable. Clinical Relevance— Horses that survive the early postoperative period and are discharged after large colon resection and anastomosis have a good chance for long‐term survival with minimal negative impact on quality of life and use.     

Obstruction of equine small intestine associated with focal idiopathic eosinophilic enteritis: An emerging disease?

Idiopathic focal eosinophilic enteritis (IFEE) is a rare disease in the horse and few cases have been reported in the literature. The objective of this paper was to describe the clinical, surgical, histological features and post-operative progress of 12 horses with IFEE, a disease that had not been identified in the authors' hospital population prior to 2000. Diagnosis of IFEE was made at laparotomy and confirmed by histological examination of resected abnormal small intestine. In all 12 horses colic was associated with jejunal obstruction involving visibly striking and palpably thickened serosal plaques or circumferential constrictions. Surgical resection of affected intestine was performed in 10 horses, of which seven completely recovered. In one horse, on which surgical resection was not performed, ingesta re-obstructed post-operatively at one of the lesions. Histological examination of resected intestines revealed, in all cases, severe transmural enteritis in which eosinophilic leucocytes were the predominant inflammatory cells. No helminths were identified and the cause of this lesion is not known. IFEE is an uncommon but significant cause of small intestinal obstruction for which surgical resection can be curative. The gross lesions may be under-recognised and histology is essential for diagnosis.     

Identification of predictors of salmonella shedding in adult horses presented for acute colic

Background

Colic has been associated with shedding of Salmonella. Horses with salmonellosis typically develop diarrhea, fever, and leukopenia. Overlooking additional predictors may result in failure to detect shedding horses and increase environmental contamination.

Objectives

Evaluate associations between signalment and clinicopathologic data during early hospitalization and Salmonella shedding in horses treated for acute colic.

Animals

Horses with acute colic admitted to a referral hospital. A total of 59 horses shedding Salmonella compared to 108 Salmonella‐negative horses.

Methods

Retrospective case‐control study evaluating patient and Salmonella culture data. Associations between variables and Salmonella shedding were identified using logistic regression. Two multivariable models were developed pertaining to (1) information available within 24 hours of admission and (2) clinical findings that developed later during hospitalization.

Results

Variables retained for multivariable model 1 indicated that Warmbloods and Arabians had increased odds for shedding Salmonella, as did horses requiring surgery (OR, 2.52; 95% CI, 1.10–5.75) or having more severe gastrointestinal disease (OR, 2.59; 95% CI, 1.08–6.20). Retained variables for model 2 demonstrated that horses that were treated surgically (OR, 1.60; 95% CI, 0.70–3.62), developed fever >103°F (OR, 2.70; 95% CI, 0.92–7.87), had abnormal leukocyte count (OR, 1.38; 95% CI, 0.61–3.09), or became inappetent and lethargic (OR, 16.69; 95% CI, 4.08–68.24) had increased odds for shedding Salmonella.

Conclusions and Clinical Importance

In horses with acute colic that present without signs of diarrhea, fever, or leukopenia, additional predictors associated with shedding Salmonella could be used to more promptly identify horses likely to shed organisms .     

Risk factors for development of acute laminitis in horses during hospitalization: 73 cases (1997-2004)

OBJECTIVE: To identify risk factors for development of acute laminitis in horses during hospitalization for illness or injury. DESIGN: Retrospective case-control study. ANIMALS: 73 horses that developed laminitis (case horses) and 146 horses that did not develop laminitis (control horses) during hospitalization. PROCEDURES: Case and control horses were matched in a 2:1 ratio by the date on which each horse was evaluated. Potential risk factors investigated included age, breed, and sex; highest and lowest values recorded during hospitalization for fibrinogen concentration, WBC count, PCV, and total solids concentration; and comorbid disease states, including pneumonia, endotoxemia, diarrhea, medically treated colic, surgically treated colic, pituitary adenoma, retained placenta or metritis, forelimb lameness, hind limb lameness, acute renal failure, and vascular abnormalities. A univariate screening of all potential risk factors was performed to determine which variables should be selected for further analysis. All factors found to be associated with development of laminitis were included in a multivariate conditional logistic regression model. RESULTS: Development of laminitis was marginally associated with lowest and highest fibrinogen concentrations, highest PCV, and lowest total solids concentration and significantly associated with pneumonia, endotoxemia, diarrhea, abdominal surgery for colic, and vascular abnormalities. In the multivariate analysis, only endotoxemia was significantly associated with laminitis. CONCLUSIONS AND CLINICAL RELEVANCE: Endotoxemia is an important risk factor for development of acute laminitis in horses during hospitalization for medical or surgical conditions. Early recognition of endotoxemia, or the potential for it to develop in certain disease states, and initiation of treatment directed at endotoxemia or its consequences may help prevent laminitis in horses during hospitalization.     

Prognosis in equine medical and surgical colic

A retrospective study was performed on 649 horses admitted to the Clinic of Equine Internal Medicine (Utrecht University) for gastrointestinal colic. The aim of this study was to provide a better guideline for determining prognosis in horses with colic. Short- and long-term survival were evaluated, and Cox regression analysis was performed to identify the clinical and clinicopathologic variables usable to predict survival. Intestinal displacements and strangulations were the most frequently diagnosed causes of colic. Regarding the surgically treated horses, 54% were discharged and 88% of these were still alive after 1 year. In comparison, 85% of medically treated patients were discharged and 93% were still alive after 1 year. Only 4.4% of all long-term survivors did not return to the expected level of performance, and 32% suffered from recurrent colic. Duration of colic signs, heart rate, intestinal motility, skin tenting, level of pain, and gross appearance of peritoneal fluid were shown to be significantly associated with survival. White blood cell count, packed cell volume, blood pH, and color of the mucous membranes did not show any prognostic significance. Thus, clinical variables appeared to be the most relevant predictors of the outcome of gastrointestinal colic.     

Partial gastrectomy and total splenectomy for the treatment of a gastric mass in a horse

A 9-year-old cob mare with a history of recurrent colic presented during an acute colic episode. Ultrasonography revealed a mass emanating from the greater curvature of the stomach and was tightly adhered to the cranial edge of the spleen. Partial gastrectomy and total splenectomy were performed via a midline celiotomy incision. The mass was subsequently confirmed to be granulomatous inflammation, postulated to be secondary to a penetrating injury to the stomach. Post-operatively, the mare had episodes of recurrent colic that were successfully managed with optimisation of the horse's diet and feeding regime. At 10 months’ post-operatively the mare was managed on full turn out, with no evidence of colic and had returned to the previous level of ridden work. The horse then presented 14 months post-operatively with severe colic due to a large colon impaction and displacement and was euthanased. This is the first report to describe successful partial gastrectomy as a treatment option for a gastric mass in the horse.     

A Clinical Trial of Probiotic Administration for Prevention of Salmonella Shedding in the Postoperative Period in Horses With Colic

The purpose of this study was to evaluate the effects of probiotic administration on the prevalence of fecal shedding of Salmonella , the prevalence of postoperative diarrhea, the length of antimicrobial therapy, and the length of the hospitalization stay during the postoperative period in horses with colic. Two commercially available probiotics for horses were used in a double-blind prospective study of 200 horses undergoing surgery for colic. Probiotic or placebo was administered PO once a day for 7 days postoperatively, and fecal cultures for Salmonella were obtained daily for 10 days. After selection of 186 patients completing the treatment protocol, the results indicated that the commercial probiotic formulations had no effect on Salmonella shedding, prevalence of diarrhea, length of antimicrobial therapy, or length of hospitalization ( P > .05). Twenty percent of the horses yielded 1 or more positive fecal cultures for Salmonella; of these horses, 74% were classified as asymptomatic shed-ders. Twenty-six percent of all horses had fluid diarrhea postoperatively, with only 12% of these horses having positive fecal cultures for Salmonella , The most common isolate was Salmonella krefeld (24 of 39 isolates). Among the different gastrointestinal disorders, horses with feed and sand impactions appeared to be more prone to shed Salmonella .     

Prevalence of Clostridium perfringens enterotoxin and Clostridium difficile toxin A in feces of horses with diarrhea and colic.

OBJECTIVE: To determine prevalence of clostridial enterotoxins in feces of horses with diarrhea and colic, and to determine whether an association exists between detection of clostridial enterotoxins in feces and development of diarrhea as a complication of colic. DESIGN: Prospective case series and case-control study. ANIMALS: 174 horses with diarrhea, colic, or problems not related to the gastrointestinal tract. PROCEDURE: Horses were assigned to 1 of 4 groups: colic with diarrhea (group 1; n = 30); colic without diarrhea (group 2; 30); diarrhea without colic (group 3; 57); and control (group 4; 57). Feces were evaluated by use of ELISA to detect Clostridium perfringens enterotoxin (CPE) and C difficile toxin A (TOXA). Frequency of detection of CPE or TOXA in groups 1 and 3 was compared with that in groups 2 and 4, respectively. RESULTS: Prevalence of enteric clostridiosis in horses in group 3 was 25%. Clostridium perfringens enterotoxin was detected in 9 of 57 (16%), TOXA in 8 of 57 (14%), and both toxins in 3 of 57 (5%) fecal samples collected from these horses. Neither toxin was detected in feces of the age-matched horses in group 4. Clostridial enterotoxins were detected in feces of 7 of 60 (12%) horses with colic (groups 1 and 2), however, a significant association was not found between detection of enterotoxins in feces and development of diarrhea as a complication of colic. CONCLUSIONS AND CLINICAL RELEVANCE: Clostridia are important etiologic agents of diarrhea in horses. Additionally, changes in intestinal flora of horses with colic may allow for proliferation of clostridia and elaboration of enterotoxins regardless of whether diarrhea develops.     

Plasma serotonin in horses undergoing surgery for small intestinal colic

This study compared serotonin concentrations in platelet poor plasma (PPP) from healthy horses and horses with surgical small intestinal (SI) colic, and evaluated their association with postoperative ileus, strangulation and non-survival. Plasma samples (with EDTA) from 33 horses with surgical SI colic were collected at several pre- and post-operative time points. Serotonin concentrations were determined using liquid-chromatography tandem mass spectrometry. Results were compared with those for 24 healthy control animals. The serotonin concentrations in PPP were significantly lower (P < 0.01) in pre- and post-operative samples from surgical SI colic horses compared to controls. However, no association with postoperative ileus or non-survival could be demonstrated at any time point. In this clinical study, plasma serotonin was not a suitable prognostic factor in horses with SI surgical colic.     

Inflammatory bowel disease in horses: 11 cases (1988-1998).

OBJECTIVE: To determine clinical and surgical abnormalities in, and long-term outcome of, horses that undergo surgery because of colic secondary to inflammatory bowel disease (IBD). DESIGN: Retrospective study. ANIMALS: 11 horses. PROCEDURE: Medical records of horses that had undergone abdominal surgery and in which IBD had been diagnosed on the basis of histologic examination of intestinal biopsy specimens were reviewed. RESULTS: 5 horses were examined because of acute colic and 6 were examined because of chronic colic. At surgery, all 11 horses had edematous or hemorrhagic bowel segments suggestive of IBD. In addition, 6 horses had circumferential mural bands (CMB) causing constriction of the small (4 horses) or large (2) intestine. Intestinal resections were performed in 7 horses. All 11 horses survived surgery and were discharged from the hospital; 10 horses were still alive at the time of follow-up (1.5 to 7 years after surgery). CLINICAL IMPLICATIONS: Results suggest that IBD is an uncommon cause of colic in horses. Surgical resection of segments of intestine with constrictive CMB may relieve clinical signs of colic. Horses with IBD that had surgery had a good prognosis for long-term survival.     

Effect of Omentectomy on Adhesion Formation in Horses

Objective —To determine if omentectomy would decrease the frequency of postoperative intraabdominal adhesions. Study Design —Retrospective study. Animals or Sample Population—44 horses that had either two ventral median celiotomies or a ventral median celiotomy and a necropsy more than 4 days later; 19 of these horses had their omentum removed at the initial surgery. Methods —Data retrieved from the records included location and type of intraabdominal adhesions; location of the surgical lesion; relationship of adhesions to the surgical lesion; surgical procedures; duration of initial surgery; time interval between procedures; age, gender, and breed of the horse; and clinical outcome. Fisher's exact test was used to evaluate the association between categorical explanatory and outcome variables. The effect of potential risk factors on the incidence rate of adhesion formation was estimated using a proportional hazards regression model. Results —Of 25 horses in the nonomentectomy group, 15 (60%) had postoperative adhesions that resulted in the need for a second surgical intervention, whereas of 19 horses that had omentectomy initially, only 4 (21%) had postoperative adhesions that required a second procedure. Rate of adhesion formation was higher in horses that did not have omentectomy initially (incidence ratio rate [IRR], 0.46; 90% confidence interval [CI], 0.18 to 1.19). At initial surgery, 24 horses had a small intestinal lesion, and 20 horses had a large intestinal lesion. Fifteen horses (63%) with small intestinal lesions subsequently developed adhesions compared with four horses (20%) with an initial large intestinal lesion (P= .006). At the second procedure, small intestine lesions were identified in 32 horses and large intestine lesions in 12 horses (1 horse had both small and large intestine lesions), and 1 horse had a gastric lesion. Adhesions were identified as the cause of colic signs in 19 (61%) horses with small intestinal lesions and in none of the horses with large intestine lesions. The frequency of adhesion development leading to colic associated with only the small intestine at the second surgery or necropsy was significantly greater (P= .001) than the frequency only in the large intestine. Conclusions —Omentectomy reduced the rate of postoperative adhesion formation. Adhesions are more likely to occur after small intestinal surgery and if they do occur likely involve the small intestine. Clinical Relevance —Omentectomy is a safe procedure and should be considered prophylactically for reduction of adhesion formation after abdominal surgery in horses.     

Disseminated alimentary mycobacteriosis in the horse: a retrospective study of nine cases

This paper summarises the clinical findings of 9 cases of disseminated alimentary mycobacteriosis in horses presented at a Finnish referral equine hospital 2009–2014. Four of 9 horses were Standardbreds and 8/9 horses were male. The median age was 2 years, ranging from 6 months to 15 years. The duration of clinical signs before admission ranged from 2 weeks to 6 months. All horses demonstrated deterioration of the clinical signs after a protracted period of the disease and were finally subjected to euthanasia after poor response to multiple medical therapies. The most common complaints on admission were weight loss and diarrhoea (9/9), pyrexia (7/9), ventral oedema (7/9), lethargy (7/9) and inappetance (6/9). The most common clinicopathological abnormalities were hypoalbuminaemia and hyperfibrinogenaemia, which were present in all horses. Rectal biopsy specimens were examined from 5/9 horses and specimens were stained with Ziehl‐Nielsen (ZN). At rectal biopsy, mild multifocal neutrophilic or mild granulomatous proctitis was recognised in all 5 horses, but the ZN stain for mycobacteria was positive in only one biopsy. A liver biopsy was taken from one horse in which hepatomegaly was observed clinically and revealed marked granulomatous hepatitis with the presence of mycobacteria. The rectal biopsy from this horse was ZN negative. At post mortem examination, chronic, multifocal to coalescing granulomatous typhlocolitis and lymphadenitis were found in all horses with the small intestine less frequently involved. At histopathological examination of post mortem samples, a ZN stain was performed and intracellular acid‐fast bacilli were identified in macrophages and multinucleated giant cells in the large intestine, liver and lymph nodes in 9/9 horses and in the small intestine in 5/9 horses. Mycobacterium avium ssp. hominissuis was isolated in 5/9 horses from post mortem samples.     

Clinical and ultrasonographic evaluation of three suture techniques for closure of the equine linea alba

Surgical technique plays an important role in preventing ventral midline incisional complications. The aim of this study was to compare the clinical and ultrasonographic outcome of three suture techniques for closure of the linea alba. In this prospective case series (n = 43), horses operated for acute abdominal intestinal disease through a midline incision were randomised in three groups: closure with a conventional continuous technique (Group 1), a small stitches continuous technique (Group 2) and the UX-technique (shoe-lace configuration, Group 3). Age, sex, body weight, type and duration of surgery were recorded and the suture to wound length ratio was calculated. Clinical evaluation of the wound (wound discharge) was performed daily during hospitalisation. At 7 weeks post-operatively the linea alba was evaluated clinically and ultrasonographically. The linea alba width was measured halfway along the length of the incision. One horse in Group 1 had acute incisional dehiscence, but there were no further significant differences between the groups in the short term. Seven weeks post-operatively two horses had complete herniation in Group 1 and one horse had partial herniation in Group 2. In the UX group no herniation occurred. The incidence of herniation was not significantly different between the groups. On ultrasound at 7 weeks the linea alba width was significantly smaller in Group 2 (P = 0.00029) and Group 3 (P = 0.0018) compared with Group 1, even with exclusion of the acute incisional dehiscence and two herniated horses. Limitations were the small group size and relatively low incidence of incisional complications for statistical analysis. It was concluded that the use of small stitches and the UX-technique resulted in a smaller linea alba width compared with the conventional continuous suture technique and might therefore be preferred for closure of the linea alba in equine colic surgery.     

Short-and long-term evaluation of surgical treatment of strangulating obstructions of the small intestine in horses: a review of 224 cases

A retrospective study was carried out of 224 horses operated for strangulating small intestine obstructions. Fifty-four horses were euthanized and 5 horses died during surgery which means that 165 (73%) were allowed to recover. Of these, 53 horses were euthanized or died in the clinic and 112 (50%) were discharged from the hospital. Of 90 horses available for follow-up 1 year postoperatively, 76 (84%) were still alive. The most important causes of death or reasons for euthanasia in the direct post-operative period were post-operative paralytic ileus, (adhesive) peritonitis and intra-abdominal haemorrhage. After discharge from the hospital the reasons were (adhesive) peritonitis and (recurrent) colic. Of the horses which survived for at least 1 year, 16% sometimes suffered from colic, 12% experienced problems with incisional woundhealing and 4% suffered from jugular vein thrombosis. All were in good or reasonable condition and 88% performed at (approximately) the same level as before the operation. The type of surgical intervention (i.e. enterotomy, enterectomy) did not significantly influence the outcome of surgery, whereas the type of anastomosis did. End-to-end jejunojejunostomy had a better prognosis than side-to-side jejunocaecostomy. It was concluded that strangulating obstructions of the small intestine still carry a poor to guarded prognosis. Mortality was highest in the direct peri-operative period. Once discharged from hospital, prognosis can be considered to be fair to good. Attempts to improve outcome should be directed at a better handling of the ileal stump during surgery and at the prevention of post-operative ileus and the formation of adhesions.     

Cardiorespiratory effects of enoximone in anaesthetised colic horses

Reasons for performing study: No studies have been reported on the effects of enoximone in anaesthetised colic horses. Objective: To examine whether enoximone improves cardiovascular function and reduces dobutamine requirement in anaesthetised colic horses. Methods: Forty‐eight mature colic horses were enrolled in this prospective, randomised clinical trial. After sedation (xylazine 0.7 mg/kg bwt) and induction (midazolam 0.06 mg/kg bwt, ketamine 2.2 mg/kg bwt), anaesthesia was maintained with isoflurane in oxygen and a lidocaine constant rate infusion (1.5 mg/kg bwt, 2 mg/kg/h). Horses were ventilated (PaCO₂<8.00 kPa). If hypotension occurred, dobutamine and/or colloids were administered. Ten minutes after skin incision, horses randomly received an i.v. bolus of enoximone (0.5 mg/kg bwt) or saline. Monitoring included respiratory and arterial blood gases, heart rate (HR), arterial pressure and cardiac index (CI). Systemic vascular resistance (SVR), stroke index (SI) and oxygen delivery index (DO₂I) were calculated. For each variable, changes between baseline and T10 within each treatment group and/or colic type (small intestines, large intestines or mixed) were analysed and compared between treatments in a fixed effects model. Differences between treatments until T30 were investigated using a mixed model (α= 0.05). Results: Ten minutes after enoximone treatment, CI (P = 0.0010), HR (P = 0.0033) and DO₂I (P = 0.0007) were higher and SVR lower (P = 0.0043) than at baseline. The changes in CI, HR and SVR were significantly different from those after saline treatment. During the first 30 min after enoximone treatment, DO₂I (P = 0.0224) and HR (P = 0.0003) were higher than after saline administration. Because the difference in HR between treatments was much clearer in large intestine colic cases, an interaction was detected between treatment and colic type in both analyses (P = 0.0076 and 0.0038, respectively). Conclusions: Enoximone produced significant, but short lasting, cardiovascular effects in colic horses. Potential relevance: Enoximone's cardiovascular effects in colic horses were of shorter duration than in healthy ponies.