The usability of peritoneal lactate concentration as a prognostic marker in horses with severe colic admitted to a veterinary teaching hospital

Colic can be a life‐threatening condition in horses and there is a need for parameters that can help determine the prognosis and need for surgery. The aim of the study was to investigate whether peritoneal fluid (PF) lactate concentration is useful for this purpose in horses with severe colic presented to a veterinary hospital. During a 16 month period, the peritoneal fluid (PF) lactate concentration was measured in 74 of 760 colic horses admitted to the Utrecht University equine clinic using a portable analyser. When comparing survivors and nonsurvivors, heart rate, PF and blood lactate concentrations and blood glucose concentration were significantly higher in horses that did not survive. No horse with a PF lactate concentration >9.4 mmol/l survived. The presence of a strangulating lesion was also significantly associated with nonsurvival, as was PF colour: no horse with red PF survived in the present series. In horses with yellow PF, the blood glucose concentration was correlated with the presence of a strangulating intestinal lesion. Peritoneal lactate concentrations can be easily and rapidly measured using a portable analyser and may be useful in assessing the prognosis and/or need for surgery in equine colic cases.     

Colic in geriatric compared to mature nongeriatric horses. Part 1: Retrospective review of clinical and laboratory data

Reason for performing study: It is the impression of some surgeons that geriatric horses have a lower survival rate compared to mature nongeriatric horses following colic surgery. One possible reason for this is that geriatric horses may be more critically ill at admission and have more severe disease than mature nongeriatric horses. Objective: To compare admission historical, physical examination and laboratory data for geriatric and mature nongeriatric horses referred for signs of colic. Methods: Medical records of horses admitted with a presenting complaint of colic between 2000 and 2006 were reviewed. Geriatric horses ≥16 years (n = 300) and mature nongeriatric horses 4–15 years (n = 300). Information obtained included duration of colic prior to admission, admission level of pain, heart rate, intestinal borborygmi, packed cell volume (PCV), plasma creatinine and blood lactate concentrations and peritoneal fluid total protein. Data were analysed using a Chi‐squared test or an analysis of variance. Level of significance was P<0.05. Results: There was no difference between geriatric and mature horses in the duration of colic prior to admission or in admission heart rate, PCV, or plasma creatinine or blood lactate concentrations. However, geriatric horses were more likely to be moderately painful and less likely to be bright and alert than mature horses; and less likely to have normal intestinal borborygmi than mature horses. Peritoneal fluid total protein concentration was higher in geriatric than mature horses. Conclusions and potential relevance: Geriatric horses presenting with signs of colic had a similar admission cardiovascular status based on heart rate, PCV, and plasma creatinine and blood lactate concentration to mature horses. Geriatric horses, however, may have different causes of colic, which may be more serious than mature horses based on pain, lack of intestinal borborygmi and peritoneal fluid total protein concentration.     

Evaluation of peritoneal fluid lactate as a marker of intestinal ischaemia in equine colic

REASONS FOR PERFORMING STUDY: The most common cause of death as a direct result of colic is acute circulatory failure secondary to intestinal ischaemia. Early and accurate recognition of ischaemic bowel is essential to decrease complications and increase survival. Blood to peritoneal lactate values have been evaluated as a prognostic indicator, but lactate values characterised by type of lesion have not been reported. HYPOTHESIS: Plasma and peritoneal lactate values are higher in horses with intestinal ischaemia secondary to a strangulating obstruction (ISSO). METHODS: Venous blood and peritoneal fluid were collected sequentially from 20 clinically healthy horses and 189 horses admitted for colic during a one-year period. Blood gas, pH, electrolyte (K+, Na+, Ca++, Cl-), glucose and lactate values were determined for blood and peritoneal fluid samples; other values recorded for peritoneal fluid included gross appearance, total protein and nucleated cell count. Information regarding diagnosis, treatment and outcome was retrieved from the medical records. RESULTS: Peritoneal and plasma levels of lactate were lower in control compared to clinical cases. Horses with ISSO had a higher peritoneal lactate value (8.45 mmol/l) than those with nonstrangulating obstruction (2.09 mmo/l). Factors with the strongest correlations with the presence of ISSO were changes in the gross appearance of the peritoneal fluid and values of peritoneal fluid chloride, pH and log10 lactate. CONCLUSIONS: Analysis of peritoneal fluid gross appearance, pH, lactate and chloride can be used for diagnosis of ISSO. POTENTIAL RELEVANCE: Peritoneal fluid lactate is a better predictor of ISSO than blood lactate and may aid in early detection of catastrophic peritoneal lesions such as intestinal strangulation and rupture.     

Myeloperoxidase assay in plasma and peritoneal fluid of horses with gastrointestinal disease

Gastrointestinal disorders, especially strangulating intestinal obstructions, are still a major cause of illness and death in the horse. Circulating lipopolysaccharides may activate both neutrophils and monocytes. The activated neutrophils release myeloperoxidase (MPO), a specific enzyme with strong oxidative activity. The aim of this study was to evaluate MPO concentrations in the plasma and peritoneal fluid (PF) of horses with colic and to check the hypothesis that these concentrations would be higher in a case of strangulating obstruction than in cases of nonstrangulating disease. By using a specific enzyme-linked immunosorbent assay for equine MPO, we determined the MPO concentrations in horses admitted to a clinic for colic. Horses with nonstrangulating or strangulating obstruction of the large intestine (NSLI or SLI), strangulating obstruction of the small intestine (SSI), or inflammatory bowel disease (IBD) were compared with healthy horses. The horses with SLI, SSI, or IBD had significantly higher MPO levels in plasma and PF than did those in the other 2 groups. The mean plasma level was significantly higher in the horses with NSLI than in the healthy horses. High MPO values in PF indicated necrotic bowel. These results show that neutrophil activation occurs during nonstrangulating and strangulating intestinal obstruction in horses and that the plasma and PF MPO concentrations may be a marker of the severity of the disease.     

Ultrasonographic features of pedunculated lipomas in two horses

Small intestine strangulation by pedunculated lipomas is a common cause of acute colic in horses. However, diagnosis of this condition prior to surgery may be difficult due to the poor specificity of the clinical signs. We describe the ultrasonographic findings of 2 horses presented for acute colic with a diagnosis of strangulating lipoma confirmed in surgery. Lipomas were identified as rounded and well‐defined, homogeneous hyperechoic structures, surrounded by distended small intestine loops and peritoneal fluid. Ultrasonographic identification of lipomas should be attempted during an abdominal scan, especially in horses with evidence of small intestinal ileus and/or obstruction.     

Evaluation of activated neutrophils in the blood of horses with colic

OBJECTIVE: To evaluate the activation status of neutrophils in blood samples obtained from horses with naturally occurring colic associated with strangulating obstruction, nonstrangulating obstruction, or inflammatory bowel disease. ANIMALS: 30 horses with naturally occurring colic and 30 healthy control horses. PROCEDURE: Activation status of neutrophils was determined by assessing the number of neutrophils that could pass through filters with 5-microm pores, cell-surface CD11-CD18 expression, and alterations in size and granularity of neutrophils. RESULTS: Horses with impaction or gas colic did not have evidence of activated neutrophils. Horses with inflammatory bowel disease consistently had evidence of activated neutrophils, including decreased leukocyte deformability, increased CD11-CD18 expression, increased neutrophil size, and decreased neutrophil granularity. Horses with strangulating colic had variable results. Of horses with strangulating colic, 7 of 14 had marked changes in filtration pressures, 5 of 14 had increased CD11-CD18 expression, 6 of 14 had changes in neutrophil size, and 5 of 14 had changes in neutrophil granularity. Among horses with strangulating colic, changes in deformability, size, and granularity of neutrophils correlated with an adverse outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Activated neutrophils were detected in all horses with inflammatory bowel disease and a few horses with strangulating colic. Correlation of activated neutrophils with horses that had strangulating colic that died or were euthanatized indicates that activated neutrophils are a negative prognostic indicator. Additional studies are needed to determine whether activated neutrophils contribute directly to the adverse outcome in horses with strangulating colic.     

Tumor Necrosis Factor and Interleukin-6 Activity and Endotoxin Concentration in Peritoneal Fluid and Blood of Horses with Acute Abdominal Disease

The purpose of this study was to evaluate the diagnostic and prognostic significance of tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) activities and endotoxin concentration in blood and peritoneal fluid of 155 adult horses with acute abdominal disease (colic). Samples also were obtained from 20 healthy adult horses. Blood and peritoneal fluid supernatant TNF and IL-6 activities and endotoxin concentration were significantly greater in horses with colic, compared with healthy horses. In horses with colic, the peritoneal fluid endotoxin concentration and TNF and IL-6 activities were significantly greater than those in blood. Within the colic group, peritoneal fluid IL-6 activity was the analyte that was most frequently increased. Blood and peritoneal fluid supernatant TNF and IL-6 activities were significantly greater when endotoxin was detected in the same sample. Blood and peritoneal fluid IL-6 activity was significantly greater in horses with inflammatory or strangulating lesions, compared with horses having nonstrangulating or noninflammatory lesions. Compared with all other data categories, diagnostic accuracy for nonsurvival was greatest (80%) when blood IL-6 activity exceeded 60 units/mL. The results of this study indicate that endotoxin was present in the peritoneal cavity of at least one third of horses with any acute disease of the abdomen. In horses presented for colic, blood or peritoneal fluid IL-6 activity was more useful than either TNF activity or endotoxin concentration for distinguishing lesion type. Although diagnostic accuracy for the prediction of nonsurvival was good for all of the analytes, negative values were more useful in the prediction of a favorable outcome than were abnormally increased values in the prediction of mortality.     

Determination of the source of increased serotonin (5-HT) concentrations in blood and peritoneal fluid of colic horses with compromised bowel

REASONS FOR PERFORMING STUDY: Increased plasma (5-HT) concentrations are reported in horses predisposed to develop laminitis and after i.v. infusion of endotoxins. In the equine jejunum contractile 5-HT1A-like receptors show tachyphylaxia upon prolonged activation with 5-HT. Therefore, increased systemic 5-HT release in colic horses could play a possible role in the pathophysiology of ileus. OBJECTIVE: To investigate possible increased systemic release of 5-HT in colic horses with compromised bowel and to identify the source of 5-HT overload. METHODS: Concentrations of 5-HT were determined in plasma and peritoneal fluid (PF) of healthy horses (n = 10), strangulating small intestinal colic horses (n = 18), nonsurgical colic horses (n = 10) and cryptorchid stallions (n = 6). It was attempted to identify the source of 5-HT overload by comparing the blood and PF 5-HT concentrations within horses and by assessing the in vivo platelet activation through determination of the beta-thromboglobulin (beta-TG)/platelet factor 4 (PF4) ratio. RESULTS: All horses in the strangulating small intestinal colic group had plasma (P = 0.006) and PF (P = 0.01) 5-HT concentrations above those found in the control group. Plasma beta-TG/PF4 ratio in these horses exceeded 2 in all cases, indicating in vivo platelet activation. Concentrations of 5-HT in PF of colic horses with compromised bowel were significantly lower than the corresponding plasma concentrations (P = 0.005). Potential relevance: In horses with compromised bowel, significant amounts of 5-HT can be released into the systemic circulation, through massive release of platelet-stored 5-HT. 5-HT is a very potent proinflammatory, vasoconstrictive and immunomodulatory agent. In view of the rapid and prolonged tachyphylaxia, shown for the jejunal 5-HT1A-like receptors, this increased systemic 5-HT release could play a role in the pathophysiology of ileus in horses.     

Serum tumor necrosis factor activity in horses with colic attributable to gastrointestinal tract disease.

Over a 24-month period, serum tumor necrosis factor (TNF) activity was determined in 289 horses with colic attributable to gastrointestinal tract disease. Serum TNF activity was quantitated by use of a modified in vitro cytotoxicity bioassay, using WEHI 164 clone-13 murine fibrosarcoma cells. Causes for colic, determined by clinical and laboratory evaluation, exploratory celiotomy, or necropsy included: gastrointestinal tract rupture (GTR); ileal impaction; small intestinal strangulating obstruction (SIO); proximal enteritis (PE); transient small intestinal distention; large-colon displacement; large-colon volvulus; large-colon impaction; colitis; small-colon obstruction; peritonitis; and unknown. Each diagnosis was placed into 1 of 3 lesion categories: inflammatory disorders (GTR, PE, colitis, peritonitis); strangulating intestinal obstruction (SIO, large-colon volvulus); and nonstrangulating intestinal obstruction (ileal impaction, transient small intestinal distension, large-colon displacement, large-colon impaction, small-colon obstruction, unknown). The prevalence of high serum TNF activity and/or mortality were evaluated. Differences were tested at significance level of P less than 0.05. Approximately 20% of the 289 horses has serum TNF activity greater than that found in clinically normal horses (greater than 2.5 U/ml). Twenty-three horses (8%) had marked increase in serum TNF activity (greater than or equal to 10 U/ml) which was more prevalent among horses with SIO and PE than in horses of other diagnostic groups, except those with GTR. Mortality and marked increase in serum TNF activity were greater in horses with intestinal inflammatory disorders or strangulating intestinal obstruction than in horses with nonstrangulating intestinal obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lactate Dehydrogenase Activity in Abdominal Fluid From Horses With Colic

The purpose of this study was to determine whether lactate dehydrogenase (LDH) activity in abdominal fluid could be used as a prognostic indicator in horses with colic. Lactate dehydrogenase activity was measured in 27 abdominal effusions from horses with colic presented to Murdoch University Veterinary Teaching Hospital using three different LDH test methods. Lactate in effusions was also measured in 11 of the horses. Lactate dehydrogenase activity was significantly different for each test method used—the ratio of Randox wet chemistry LDH lactate to pyruvate:Randox wet LDH pyruvate to lactate (P-L):IDEXX dry chemistry P-L was approximately 1:2:4. Lactate dehydrogenase activity in the abdominal effusions was significantly higher with all methods in the horses that died or were euthanized because of abdominal sepsis or advanced neoplasia than in those that survived after treatment for colic signs because of mechanical obstructions or nonseptic abdominal inflammation. Lactate dehydrogenase activity showed moderate-to-good correlation (r = 0.73 to 0.86) with lactate concentration of the fluid. In conclusion, LDH activity in abdominal fluid may be a useful prognostic test in horses with colic. The test method for LDH measurement must be known and remain constant for meaningful interpretation. Significantly higher levels of LDH activity may be present in horses with colic because of sepsis or advanced neoplasia than in those with colic because of nonseptic inflammation or mechanical obstructions that may respond to treatment.     

Evaluation of plasma catecholamine and serum cortisol concentrations in horses with colic

OBJECTIVE: To evaluate plasma epinephrine and norepinephrine concentrations and serum cortisol concentration in horses with colic and assess the relationship of these variables with clinical signs, routinely measured clinicopathologic variables, and outcome in affected horses. DESIGN: Prospective observational study. ANIMALS: 35 horses with colic. PROCEDURE: Blood samples were collected within 30 minutes of arrival at the veterinary hospital from horses referred because of colic. Plasma and serum samples were analyzed for cortisol, epinephrine, norepinephrine, lactate, and electrolyte concentrations and acid-base variables. Heart rate at admission and outcome (survival or nonsurvival) were recorded. Univariate logistic regression was used to calculate crude (unadjusted) odds ratios and 95% confidence intervals. RESULTS: Of the 35 horses with colic, 26 survived. Higher plasma epinephrine, plasma lactate, and serum cortisol concentrations were significantly associated with increased risk of nonsurvival, but plasma norepinephrine concentration was not associated with outcome. Plasma epinephrine concentration was significantly correlated with heart rate (r = 0.68), plasma lactate concentration (r = 0.87), blood pH (r = -0.83), anion gap (r = 0.74), and base excess (r = -0.81). CONCLUSIONS AND CLINICAL RELEVANCE: The risk of death appears to be greater in colic-affected horses with high circulating concentrations of epinephrine and cortisol. The correlation of epinephrine with other biochemical markers of illness severity and with heart rate indicates that the degree of sympathetic activation in horses with colic can be inferred from routinely measured variables.     

Peritoneal d-Dimer Concentration for Assessing Peritoneal Fibrinolytic Activity in Horses with Colic

Background: Plasma d -dimer concentration is a useful marker to assess systemic coagulation and fibrinolytic activities in humans, dogs, and horses. Peritoneal fibrinolytic activity increases in horses with colic, especially in horses with endotoxin in the peritoneal fluid.
Hypothesis/Objectives: Peritoneal d -dimer concentration can be used to assess peritoneal fibrinolytic activity in horses with severe gastrointestinal (GI) disorders and altered peritoneal fluid.
Animals: Two hundred and twenty-one colic horses and 15 control horses.
Methods: Prospective observational clinical study. Blood and peritoneal fluid were collected on admission. Horses were grouped according to diagnosis, peritoneal fluid analysis, and outcome. Peritoneal d -dimer concentration was determined, together with peritoneal tissue-plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) activities. Plasma d -dimer concentration also was measured.
Results: Peritoneal d -dimer concentration was significantly higher in all colic groups compared with controls, and in horses with enteritis, peritonitis, and ischemic disorders compared with horses with large intestinal obstructions. Peritoneal d -dimer concentration was significantly higher in horses with altered peritoneal fluid (modified transudate and exudate) compared with horses with normal peritoneal fluid analysis. Plasma d -dimer concentration also was significantly higher in the peritonitis group, and in horses with altered peritoneal fluid analysis. Peritoneal and plasma d -dimer concentrations also were significantly higher in nonsurvivors. Peritoneal d -dimer concentration was significantly correlated with decreased peritoneal t-PA activity and increased peritoneal PAI-1 activity.
Conclusions and Clinical Importance: Peritoneal d -dimer concentration is markedly higher in severe GI disorders, and it can be used to assess peritoneal fibrinolytic activity in horses with colic.     

Clinical evaluation of serum alcohol dehydrogenase activity in horses with acute intestinal obstruction

Objectives – To measure serum alcohol dehydrogenase (ADH) activity in horses with acute intestinal obstruction and to determine the diagnostic and prognostic utility of this analyte. Design – Prospective observational study. Setting – University Veterinary Hospital. Animals – Thirty healthy horses (control group) and 77 horses with acute intestinal obstruction, including 36 horses with nonstrangulating obstruction (23 with left ventral colon impaction and 13 with left dorsal displacement [G1], 22 with small intestinal strangulation [G2], and 19 with colon torsion [G3]). Interventions – Serum ADH activity was assayed spectrophotometerically in all horses. Serum lactate concentration and hepatic enzyme (aspartate aminotransferase, gamma‐glutamyl transferase, glutamate dehydrogenase) activities were measured using an automatic analyzer. Measurements and Main Results – The median [interquartile range] serum ADH activity in healthy horses was 10.5 [8.7 – 11 U/L]. ADH activity was significantly increased (P<0.05) in G1=16.5 [13.8 – 18 U/L], G2=40 [20 – 74.9 U/L], and G3=63.2 [40 – 78 U/L] compared with healthy controls. Aspartate aminotransferase and glutamate dehydrogenase activities were also significantly increased in G3 in comparison with controls. ADH activity was correlated with serum lactate concentration in G1 and G3, respectively (P<0.01, r=0.55 and 0.8). Other liver enzymes did not show any significant correlation with lactate. ADH activity was directly related to the probability of strangulation; odds ratio=1.11. ADH activity >20 U/L had 80.6% specificity and 80.5% sensitivity for discriminating horses with strangulating obstruction. Twelve horses euthanized before surgery were excluded from the outcome analysis. Increasing ADH activity was associated with nonsurvival; odds ratio=1.03. ADH activity <80 U/L had 94.44% specificity and 66.67% sensitivity for survival. Conclusion – Serum ADH activity may be a useful clinical parameter in detecting intestinal strangulation in horses and may provide some prognostic value in horses with acute intestinal obstruction.     

Factors for prognostic use in equine obstructive small intestinal disease

Twenty horses with small intestinal obstructions requiring surgery were evaluated prospectively. Ten horses lived (group 1) and 10 died (group 2). Eight of the horses in group 1 had simple obstruction and 7 of the horses in group 2 had strangulation obstruction. There was a significant difference (P less than 0.001) between the mean intraluminal hydrostatic pressure in horses of groups 1 and 2 (6.3 cm H2O and 15 cm H2O, respectively). The mean peritoneal fluid protein concentration in horses of groups 1 and 2 (2.8 mg/dl and 5.4 mg/dl, respectively) also differed significantly between groups (P less than 0.01). Histologic evaluation of the intestinal specimens from horses of group 1 (n = 3) and group 2 (n = 6) revealed more severe mucosal lesions in group 2. The measured values that were not significantly different between the 2 groups included PCV, total serum protein content, WBC count, anion gap, and duration of colic before admission. It was concluded that peritoneal fluid protein concentration and intraluminal hydrostatic pressure in small intestinal obstruction may be used as adjuncts to diagnosis and as prognostic indicators.     

Clinical comparison between a continuous Lembert pattern wrapped in a carboxymethylcellulose and hyaluronate membrane with an interrupted Lembert pattern for one-layer jejunojejunostomy in horses

Reasons for performing study: Although experimental studies have demonstrated differences in performance between methods for handsewn jejunojejunostomy in horses, information on clinical results after different methods of anastomosis are rare. Hypothesis: A continuous Lembert pattern wrapped in a carboxymethylcellulose and hyaluronate membrane would perform better than an interrupted Lembert pattern for jejunojejunostomy in horses. Methods: Data was reviewed on 32 horses that underwent jejunojejunostomy from 1993–2002. Kaplan‐Meier analyses and rates for post operative colic and death were used to compare outcomes after an interrupted Lembert pattern (15 horses with strangulating lesions and 5 horses with nonstrangulating lesions) and a continuous Lembert pattern with membrane (12 horses with strangulating diseases). Results: None of the 32 horses had post operative ileus or post operative endotoxaemia. One horse with a continuous pattern required a repeat celiotomy for anastomotic impaction. Short‐term survivals for the interrupted Lembert were 100% (nonstrangulating lesions) and 93% (strangulating lesions) and for the continuous pattern 92% (all strangulating). Long‐term rates for mortality and colic episodes were less for the continuous Lembert pattern with membrane compared with the interrupted Lembert for strangulating lesions (P<0.05) and were less for strangulating lesions than for nonstrangulating lesions (P<0.05). For strangulating lesions, Kaplan‐Meier analyses yielded a survival probability of 70% for up to 9 years after the interrupted Lembert pattern and 80% for up to 5 years for the continuous Lembert pattern. Conclusions and relevance: Both Lembert patterns performed well in clinical use, although the continuous pattern with the carboxymethylcellulose and hyaluronate membrane had superior long‐term outcomes with less colic and mortality from colic.     

Use of the Accusport semi-automated analyser to determine blood lactate as an aid in the clinical assessment of horses with colic

The most useful diagnostic methods in the initial evaluation of horses with colic assess the morphological and functional status of the gastrointestinal tract and cardiovascular status. This evaluation is best achieved using a combination of clinical and laboratory data. Blood lactate concentration (BL) is one of these variables. BL rises mainly due to poor tissue perfusion and anaerobic glycolysis associated with shock, providing an indicator of both the severity of disease and its prognosis. A hand-held lactate meter, Accusport, provides a rapid (60 seconds), inexpensive dry-chemical-based determination of BL. This trial evaluated the Accusport's ability to provide BL data as an adjunct to the initial clinical evaluation of horses with colic. The accuracy of the Accusport was tested by evaluation of its interchangeability with the benchmark enzymatic kit evaluation of BL in a trial using data collected firstly from 10 clinically normal control horses and subsequently from 48 horses presented with signs of colic. The BL values were recorded together with the clinical variables of heart rate (HR), capillary refill time (CRT), haematocrit (Hct), and pain character and severity on the initial assessment of the colic horses. Information regarding choice of therapeutic management (medical or surgical) and eventual case outcome (full recovery or died/euthanased) was recorded. The Accusport was found to be interchangeable with the enzymatic kit for recording BL values in colic horses with BL < 10 mmol/l, which is within the BL range associated with survival. The interchangeability of an additional, laboratory-based wet chemical assay for BL, the Stat 7 was simultaneously evaluated for the colic and control horses. The Stat 7 was found to be interchangeable with the enzymatic kit for BL determination of colic horses. No linear associations between BL values with HR, CRT, Hct or pain assessment were observed. No relationship with either selection of therapeutic method or eventual case outcome was observed. All horses with BL >8 mmol/l died or were euthanased.     

Peritoneal concentrations of transforming growth factor beta in horses with colic

Reasons for performing the study: In man, peritoneal transforming growth factor beta (TGF‐β) is associated with peritoneal diseases and subsequent adhesion formation. No studies on plasma and peritoneal TGF‐β concentrations in horses with colic are available. Objectives: 1) To determine both plasma and peritoneal TGF‐β₁ and TGF‐β₃ concentrations in horses with different types of colic (not previously subjected to abdominal surgery); 2) to compare these concentrations according to the type of peritoneal fluid (transudate, modified transudate and exudate); and 3) to compare and correlate plasma and peritoneal concentrations of TGF‐β₁ and TGF‐β₃ and the types of peritoneal fluid according to the colic group and outcome. Methods: Peritoneal fluid and plasma samples from 78 horses with colic and 8 healthy horses were obtained. Patients were classified according to diagnosis (obstructions, enteritis, ischaemic disorders and peritonitis), peritoneal fluid analysis (transudate, modified transudate and exudate), and outcome (survivors and nonsurvivors). Plasma and peritoneal TGF‐β₁ and TGF‐β₃ concentrations were determined by ELISA. Data were analysed by parametric and nonparametric tests. P≤0.05 was considered as statistically significant. Results: Concentrations of peritoneal fluid TGF‐β₁ were significantly (P = 0.01) higher in horses with peritonitis in comparison with all other colic groups and controls. Horses with ischaemic lesions had significantly (P = 0.01) higher concentrations of peritoneal TGF‐β₁ in comparison with controls and the group of horses with obstructions. Peritoneal TGF‐β₁ concentration also was significantly (P = 0.01) higher in exudates in comparison with transudates. Peritoneal TGF‐β₁ and TGF‐β₃ concentrations and plasma TGF‐β₁ concentration were significantly increased in nonsurvivors compared to survivors (P = 0.001, P = 0.004 and P = 0.05, respectively). Conclusions: Peritoneal TGF‐β₁ concentration was higher in horses with severe gastrointestinal diseases (ischaemic intestinal lesions and peritonitis), in horses with an altered peritoneal fluid (exudate), and in nonsurvivors. Potential relevance: Peritoneal TGF‐β concentration increases in horses with severe gastrointestinal disease as an anti‐inflammatory response.     

Plasma concentrations of endothelin-like immunoreactivity in healthy horses and horses with naturally acquired gastrointestinal tract disorders

OBJECTIVE: To compare plasma endothelin (ET)- like immunoreactivity between healthy horses and those with naturally acquired gastrointestinal tract disorders. ANIMALS: 29 healthy horses and 142 horses with gastrointestinal tract disorders. PROCEDURE: Blood samples were collected from healthy horses and from horses with gastrointestinal tract disorders prior to treatment. Magnitude and duration of abnormal clinical signs were recorded, and clinical variables were assessed via thorough physical examinations. Plasma concentrations of ET-like immunoreactivity were measured by use of a radioimmunoassay for human endothelin-1, and CBC and plasma biochemical analyses were performed. RESULTS: Plasma ET-like immunoreactivity concentration was significantly increased in horses with gastrointestinal tract disorders, compared with healthy horses. Median plasma concentration of ET-like immunoreactivity was 1.80 pg/ml (range, 1.09 to 3.2 pg/ml) in healthy horses. Plasma ET-like immunoreactivity was greatest in horses with strangulating large-intestinal obstruction (median, 10.02 pg/ml; range, 3.8 to 22.62 pg/ml), peritonitis (9.19 pg/ml; 789 to 25.83 pg/ml), and enterocolitis (8.89 pg/mI; 6.30 to 18.36 pg/ml). Concentration of ET-like immunoreactivity was significantly associated with survival, PCV, and duration of signs of pain. However, correlations for associations with PCV and duration of pain were low. CONCLUSIONS AND CLINICAL RELEVANCE: Horses with gastrointestinal tract disorders have increased plasma concentrations of ET-like immunoreactivity, compared with healthy horses. The greatest values were detected in horses with large-intestinal strangulating obstructions, peritonitis, and enterocolitis. This suggests a potential involvement of ET in the pathogenesis of certain gastrointestinal tract disorders in horses.     

Association between cribbing and entrapment of the small intestine in the epiploic foramen in horses: 68 cases (1991-2002)

OBJECTIVE: To determine whether there was an association between a history of cribbing and epiploic foramen entrapment (EFE) of the small intestine in horses. DESIGN: Retrospective study. ANIMALS: 68 horses examined at the University of Illinois or the University of Liverpool veterinary teaching hospitals. PROCEDURE: For horses examined at the University of Illinois that underwent surgery because of strangulating small intestine lesions, information about cribbing was obtained through telephone calls with owners. For horses examined at the University of Liverpool that underwent surgery for colic for any reason, information about cribbing was obtained through a preoperative questionnaire. RESULTS: 13 of 19 (68%) horses with EFE examined at the University of Illinois had a history of cribbing, compared with only 2 of 34 (6%) horses with other strangulating small intestine lesions (odds ratio, 34.7; 95% confidence interval, 6.2 to 194.6). Similarly, 24 of 49 (49%) horses with EFE examined at the University of Liverpool had a history of cribbing, compared with 72 of 687 (10.5%) horses with colic caused by other lesions (odds ratio, 8.2; 95% confidence interval, 4.5 to 15.1). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that there may be an association between cribbing and EFE in horses, with horses with a history of cribbing more likely to have EFE than horses without such a history.     

Association between Hyperglycemia and Survival in 228 Horses with Acute Gastrointestinal Disease

Background: Glucose homeostasis is dysregulated in critically ill humans resulting in hyperglycemia and decreased survival. Hyperglycemia is common in horses presenting with abdominal crisis, and this might be associated with a worse prognosis for survival.
Objective: To determine if hyperglycemia in horses with acute abdominal disease is associated with increased odds of failure to survive to hospital discharge.
Animals: Two hundred and twenty-eight adult horses with acute gastrointestinal disease.
Methods: Observational retrospective study. Records of horses > 1 year of age presenting for treatment of colic over a 3-year period were reviewed. Data collected included age, duration of colic, glucose, heart rate, PCV, total protein, anion gap, cost of hospitalization, breed, sex, pain at admission, diagnosis, whether surgery was performed, and life status at hospital discharge. Potential risk factors for nonsurvival were screened by univariable logistic regression and the best-fitting univariable model was used as the basis for multivariable regression modeling.
Results: Mean blood glucose was 155 mg/dL (8.5 mM) with 45% of the population above the reference range; 16.7% (38 of 228) of horses had severe hyperglycemia (>195 mg/dL; 10.7 mM). Factors associated with increased odds of failure to survive included glucose, severity of pain at admission, heart rate, PCV, anion gap, and diagnosis. The best-fitting multivariable model included glucose and diagnosis, with age included as a confounding variable. The model correctly classified outcome for 92.5% of horses.
Conclusions and Clinical Importance: This study has confirmed prior reports that hyperglycemia is common in horses with colic and is associated with a worse prognosis for survival to hospital discharge.