Analysis of Sodium Carboxymethylcellulose Administration and Related Factors Associated with Postoperative Colic and Survival in Horses with Small Intestinal Disease

Objective— To analyze the effect of the intraoperative use of sodium carboxymethylcellulose (CBMC) and related perioperative factors on postoperative colic and survival in horses that had abdominal surgery for colic.
Study Design— Retrospective study.
Animals— Horses (n=203) that had surgery for small intestinal disease; 33 horses had intraoperative administration of CBMC.
Methods— Information was obtained from medical records for 170 horses that had surgery for colic before use of CBMC and 33 horses that had intraoperative CBMC. Kaplan–Meier survival curves were used to estimate median survival time and a Cox proportional hazards model was used to estimate the hazard ratio for the effect of CBMC and other perioperative variables on survival.
Results— Seventy-five percent of horses administered CBMC survived to 180 days, whereas 75% of untreated horses survived 8 days (median survival time=18 days). Horses not administered CBMC were twice as likely to die compared with horses administered CBMC. Horses that had postoperative ileus (POI) were 1.4 times more likely to die than horses without ileus. Similarly, horses with signs of colic after surgery were 1.3 times more likely to die than horses without postoperative signs of colic.
Conclusions— CBMC administration is seemingly protective against death and prolongs survival when used intraoperatively in horses with small intestine disease, particularly horses with postoperative colic or POI. Both POI and colic increased risk of death after surgery.
Clinical Relevance— Intraoperative administration of CBMC in horses that have surgery for small intestinal disease may improve survival, possibly by reducing early adhesion formation.     

Incarceration of the Small Intestine in the Epiploic Foramen Report of 19 Cases (1983–1992)

The medical records of 19 horses referred for colic and subsequently found (18 confirmed, 1 suspected) to have small intestinal incarceration through the epiploic foramen were reviewed. These horses were of various ages and breeds; they had clinical signs of colic for an average duration of 13.5 hours before examination. Seventeen horses had nasogastric reflux, and 15 had palpable small intestinal distention. Three horses were killed during surgery because of severe intestinal damage. Of the remaining 16 horses, 13 required intestinal resection and anastomosis. The length of incarcerated small intestine varied from 8 cm to 17.6 m. The ileum was involved in 12 cases. In one horse, the mesoduodenum was disrupted before surgery, causing intra-abdominal bleeding; incarceration of bowel was not found during surgery. The short-term (1 month) survival rate was 74% (14 of 19 cases), and the long-term survival rate was 63% (12 of 19 cases). The follow-up period was 3 months to 45 months (mean 17.2 ± 7.2 months).     

Survival and complication rates in 300 horses undergoing surgical treatment of colic. Part 3: Long-term complications and survival

REASONS FOR PERFORMING STUDY: Few studies have evaluated long-term survival and complication rates in horses following surgical treatment of colic, making it difficult to offer realistic advice concerning long-term prognosis. OBJECTIVE: To review the complications occurring after discharge from hospital and survival to >12 months after surgery of 300 horses undergoing exploratory laparotomy for acute colic. Pre-, intra- and post operative factors that affected long-term complications and long-term survival were assessed. METHODS: History, clinical findings, surgical findings and procedures and post operative treatments of 300 consecutive surgical colic cases (1994-2001) were reviewed. Long-term follow-up information was retrieved from case records and telephone enquiries from owners. RESULTS: The long-term (>12 months) survival rate for 204 horses discharged after colic surgery and for which follow-up information was available was 84%. The most common complication after discharge was colic, affecting 35.1% of horses following a single laparotomy. Colic was most common in horses that had had small intestinal obstructions, bowel resection or post operative ileus. Abdominal adhesions were most common in horses that presented with severe colic due to strangulation of small intestine. Ventral hernia formation occurred in 8% of horses, and was most common in horses that had had post operative wound drainage or infection. CONCLUSIONS: This study identified various factors that appear to predispose horses to long-term complications after colic surgery. POTENTIAL RELEVANCE: Further evaluation of strategies that might reduce the incidence of such complications are needed; in particular, the value of intraperitoneal heparin should be evaluated, and procedures designed to reduce the rates of wound drainage and infection assessed.     

Long-term survival of equine surgical colic cases. Part 1: patterns of mortality and morbidity

Postoperative complications and mortality can occur many weeks or months after colic surgery. We are interested in the long-term outcome of these cases. This study documents patterns of mortality and morbidity among 341 horses that recovered from colic surgery March 1998-August 2000. The progress of each horse was rigorously followed by periodic telephone and postal questionnaires. Event time data were recorded for each animal and a total of 321 horse years of survival, together with death from all causes, colic-related death and various postoperative complications. Postoperative survival (of all horses excluding grass sickness cases) was triphasic over the first 600 days and there was marked mortality in the first 10 days postoperatively. The probability of survival postoperatively decreased to 0.87 by 10 days, 0.82 by 100 days and declined slowly to 0.75 at 600 days. Horses suffering from epiploic foramen entrapment had a significantly reduced probability of postoperative survival (RR = 2.1, P = 0.033). The causes of death for 104 horses that died postoperatively and the prevalence of postoperative complications are recorded for the study population. Postoperative colic was the most prevalent complication with 100 horses (29%) suffering one or more episodes. However, only 16 horses (4.6%) suffered 3 or more episodes. The incidence of postoperative colic was 0.55 episodes/horse year at risk. This study provides data that will inform the prognosis for postoperative colic cases and identifies epiploic foramen entrapment as carrying a worse prognosis for survival than other strangulating lesions.     

Factors affecting long-term survival of horses recovering from surgery of the small intestine

REASONS FOR PERFORMING STUDY: Epiploic foramen entrapment (EFE) has been associated with a particularly poor post operative prognosis for equine colic cases, but the reasons for this are unknown. OBJECTIVES: To identify variables associated with post operative survival following surgery for small intestinal disease; develop a model describing long-term post operative survival; and identify reasons for the poor prognosis associated with EFE. METHODS: Data from 382 horses undergoing surgery were used to identify variables associated with survival. A multivariable Cox proportional hazards model for post operative survival was developed and model fit evaluated. RESULTS: The final model included the variables total plasma protein (TP) and packed cell volume (PCV) at admission, duration of surgery and the dichotomous variable relaparotomy (yes/no). Risk of death was positively associated with increasing PCV, but negatively associated with increasing TP (which decreased the probability of death). In a univariable model, EFE cases had a significantly higher death rate than other types of small intestinal disease (hazard ratio = 1.7, P = 0.035). Multivariable modelling indicated that some of the increased risk associated with EFE cases was due to lower TP values and longer duration of surgery. CONCLUSIONS: Preoperative TP is associated negatively with the risk of post operative death in horses recovering from small intestinal surgery. Other variables associated with the probability of survival are preoperative PCV, duration of surgery and relaparotomy. The increased post operative death rate of EFE cases can be explained in part by lower TP and longer surgery times of these cases. POTENTIAL RELEVANCE: Total plasma protein may be not simply a measure of hydration status in small intestinal colic cases, but an important determinant of survival. Further investigation of this relationship is warranted. Our model for post operative survival highlights the importance of preoperative TP, PCV and duration of surgery as prognostic indicators. This information should allow a more accurate post operative prognosis following small intestinal surgery.     

Survival and complication rates in 300 horses undergoing surgical treatment of colic. Part 1: Short-term survival following a single laparotomy

REASONS FOR PERFORMING STUDY: A minority of equine colic cases prove fatal unless treated surgically; however, few studies have considered long-term survival and complication rates, and few have attempted to identify factors that might affect outcomes. Such information is required for owners and veterinary surgeons to make informed decisions about the most appropriate treatment for individual cases. OBJECTIVES: To document short-term survival rates of 300 horses undergoing colic surgery and analyse factors that might have predisposed to short-term death. METHODS: History, clinical and surgical findings, treatments and outcomes of 300 surgical colic cases (1994-2001) were reviewed. Comparisons among groups of discrete data were made using chi-squared or Student's t tests as appropriate. Significance was set at P < 0.05, and 95% confidence intervals were calculated for percentages. RESULTS: The short-term survival rate (to discharge) was 70.3% for all horses and 83.1% for those recovering from anaesthesia; for horses that had a single laparotomy it was 87.2%. The most common reasons for death/euthanasia in the post operative period after a single laparotomy were persistent pain/colic, post operative ileus and grass sickness. Horses with lesions involving the small intestine and caecum had lower survival rates (75.2 and 66.7%, respectively) than those with large colon or small colon lesions (89.9 and 100%, respectively). The survival rate for ischaemic/strangulating lesions (68.9%) was lower than for simple obstructions (90.5%). CONCLUSIONS: Short-term survival of horses undergoing exploratory laparotomy for acute colic is dependent on many factors, including the nature of the underlying disease, cardiovascular status and post operative complications. POTENTIAL RELEVANCE: These retrospective studies may be used as a basis for prospective studies assessing treatments that could ultimately improve survival and decrease complication rates.     

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.     

Long-term survival of equine surgical colic cases. Part 2: modelling postoperative survival

Colic surgery is a frequently performed operation with high postoperative mortality. This study was undertaken to identify variables associated with decreased postoperative survival. We used data from 321 horse years of postoperative survival time to model the probability of survival following recovery from colic surgery. Continuous variables were modelled using a 6 variable, penalised Cox regression model. This demonstrated approximately linear relationships between survival and the following variables: increase in packed cell volume (PCV), intestinal resection length, time to surgery (interval between onset of colic and surgery) and duration of surgery. No significant decrease in survival was demonstrated with increasing age of the patient or with heart rate. The only categorical variable to be significantly associated with decreased survival was epiploic foramen entrapment. The final, fixed effects Cox proportional hazards model of postoperative survival included the variables epiploic foramen entrapment, PCV, resection length and duration of surgery, each variable adjusted for the nonlinear relationship with time to surgery. Residual variation in postoperative survival attributable to professional personnel (referring veterinary surgeon, anaesthetist and surgeon) was explored by fitting each as a random effects term in the model. Little of the residual variation could be attributed to any category of personnel. Model diagnostics indicated little influence by individual outliers on model parameters and little evidence of subjects poorly predicted by the final model. The study highlights factors influencing the long-term survival of horses recovering from colic surgery and proposes a model that can be used to inform prognosis.     

Acute small intestinal obstruction associated with Parascaris equorum infection in young horses: 25 cases (1985-2004)

AIMS: To retrospectively evaluate the medical and surgical records of horses with acute small intestinal obstructions associated with Parascaris equorum infection; to describe the gastrointestinal lesions; and to determine the outcome of cases with such lesions. METHODS: Records of 25 horses with acute small intestinal obstruction associated with P. equorum between 1985 and 2004 were reviewed to determine signalment, history, physical examination, surgical or post-mortem findings, and outcome. RESULTS: All horses except one were less than 12 months old. Standardbreds were over-represented in the population studied. Sixteen horses (72%) had been administered anthelmintics, including pyrantel (n=8), ivermectin (n=7), and trichlorphon (n=1), within 24 h prior to the onset of colic. Of the 25 cases reviewed, 16 had simple obstructive ascarid impactions (SOAIs), and nine had complicated obstructive ascarid impaction (COAI) including volvulus (n=6) or intussusception (n=3), both concurrent with ascarid impaction of the small intestine. Short-term survival (discharge from hospital) occurred in 79% of horses treated for SOAI, and was 64% for all horses. Long-term survival (>1 year) occurred in 33% of horses with SOAI, and the overall long-term survival was 27% for all horses. Formation of adhesions was the most frequent finding associated with death for horses that did not survive long-term. CONCLUSIONS AND CLINICAL RELEVANCE: The incidence of anthelmintic treatment within 24 h of the onset of colic in this study population (72%) was higher than that previously reported. Resistance of P. equorum to ivermectin recently reported in Ontario may be associated with increased ascarid burdens, predisposing horses to ascarid impaction. The long-term survival of these horses was better than that reported previously.     

Initial investigation of mortality rates and prognostic indicators in horses with colic in Israel: A retrospective study

Reasons for performing study: Initial assessment of the mortality rates and prognostic indicators in horses with colic presented to a referral hospital in Israel. Objectives: To determine mortality rates and to identify potential prognostic indicators in horses undergoing treatment for colic. Methods: The medical records of 208 colic cases were reviewed and mortality rates calculated including 95% confidence intervals. Mortality rates in surgical cases were calculated separately for strangulating and nonstrangulating lesions as well as for lesions of the large and small intestines. Potential prognostic indicators were identified and evaluated by Student's t test or X² test, where appropriate. Those found to be significant (P<0.05) were evaluated in 2 logistic regression models; one including all horses with colic and one for surgical cases only. Results: The overall mortality rate was 51/208 (25%); 5/72 (7%) in medically treated cases, 46/136 (34%) in surgical cases, 30/50 (60%) in strangulating lesions and 15/85 (18%) in nonstrangulating lesions, 17/27 (63%) in cases involving small intestinal lesions and 28/108 (26%) in cases with large intestinal lesions. Clinical parameters found to be significantly associated with death by univariate analysis were medical/surgical treatment, location of lesion, severity of lesion, mucous membrane colour (MM), capillary refill time (CRT) and heart rate. Using a multivariate logistic regression model, including all cases, medical/surgical treatment, CRT and MM were found to be prognostic indicators and when using the surgical cases alone, only CRT and lesion severity remained related to mortality. Conclusions: Mortality rates were similar or better than those previously reported in most cases, however, studies from the USA and the UK published better success rates for small intestinal surgeries. Cultural attitudes toward euthanasia may be associated with mortality rates. Potential relevance: These results assist clinicians in providing an immediate prognosis based on clinical findings at presentation and contribute to an international database that may aid future research in improving treatment of colic.     

Colic in geriatric compared to mature nongeriatric horses. Part 2: Treatment,diagnosis and short‐term survival

Reason for performing study: Owners and veterinarians are often concerned about mortality of geriatric horses following colic surgery. Objective: To compare treatment, diagnosis and short‐term survival for geriatric compared to mature nongeriatric horses with colic. Methods: Medical records of horses admitted with a presenting complaint of colic between 2000 and 2006 were reviewed. Geriatric horses were aged ≥16 years (n = 300) and subcategorised as age ≥20 years (n = 134). Mature nongeriatric horses were age 4–15 years (n = 300). Information obtained included medical (included horses subjected to euthanasia without surgery) vs. surgical management, lesion location, type and classification, surgical procedures performed and short‐term survival. Data were analysed using a Chi‐squared test or an analysis of variance. Level of significance was P<0.05. Results: The overall short‐term survival of geriatric horses was lower than that for mature horses (59 vs. 76%, respectively). The survival of medically managed geriatric horses was lower than that for mature horses (58 vs. 80%, respectively). The survival of surgically managed geriatric horses was not different to that for mature horses (59 vs. 70%, respectively) except for geriatric horses age ≥20 years (53%). There was no difference in survival between geriatric and mature horses with small (86 and 83%, respectively) or large (78 vs. 70%, respectively) intestinal strangulating lesions or those undergoing jejunojejunostomy (75 vs. 70%, respectively). Geriatric horses with a large colon simple obstruction had a lower survival compared to mature horses (80 vs. 97%, respectively). Conclusions and potential relevance: The survival of geriatric horses with a strangulating lesion or requiring jejunojejunostomy was not different to that for mature horses. Geriatric horses presenting with colic were more likely than mature horses to be subjected to euthanasia without surgery (i.e. lower survival with medical treatment). Geriatric horses undergoing surgery for a large colon simple obstruction had a lower survival than mature horses.     

Acute small intestinal obstruction associated with Parascaris equorum infection in young horses: 25 cases (1985–2004)

AIMS: To retrospectively evaluate the medical and surgical records of horses with acute small intestinal obstructions associated with Parascaris equorum infection; to describe the gastrointestinal lesions; and to determine the outcome of cases with such lesions.

METHODS: Records of 25 horses with acute small intestinal obstruction associated with P. equorum between 1985 and 2004 were reviewed to determine signalment, history, physical examination, surgical or post-mortem findings, and outcome.

RESULTS: All horses except one were less than 12 months old. Standardbreds were over-represented in the population studied. Sixteen horses (72%) had been administered anthelmintics, including pyrantel (n=8), ivermectin (n=7), and trichlorphon (n=1), within 24 h prior to the onset of colic. Of the 25 cases reviewed, 16 had simple obstructive ascarid impactions (SOAIs), and nine had complicated obstructive ascarid impaction (COAI) including volvulus (n=6) or intussusception (n=3), both concurrent with ascarid impaction of the small intestine. Short-term survival (discharge from hospital) occurred in 79% of horses treated for SOAI, and was 64% for all horses. Long-term survival (>1 year) occurred in 33% of horses with SOAI, and the overall long-term survival was 27% for all horses. Formation of adhesions was the most frequent finding associated with death for horses that did not survive long-term.

CONCLUSIONS AND CLINICAL RELEVANCE: The incidence of anthelmintic treatment within 24 h of the onset of colic in this study population (72%) was higher than that previously reported. Resistance of P. equorum to ivermectin recently reported in Ontario may be associated with increased ascarid burdens, predisposing horses to ascarid impaction. The long-term survival of these horses was better than that reported previously.     

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.     

Modelling long-term survival of horses following surgery for large intestinal disease

REASONS FOR PERFORMING STUDY: Large intestinal diseases are an important cause of equine colic that require surgical management, but there is little published information about long-term survival of such cases. OBJECTIVES: To identify variables associated with post operative mortality and to develop a model for post operative survival following surgery for large intestinal disease. METHODS: Clinical data and long-term follow-up information from 275 horses undergoing surgery for large intestinal disease were used. A multivariable, Cox proportional hazards model for post operative death was developed and the fit of the model evaluated. RESULTS: The continuous variables age, heart rate and packed cell volume (PCV) were associated positively with the risk of post operative death, as were the categorical variables resection (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.2-5.1) and relaparotomy (OR 3.5, 95% CI 1.4-8.4). CONCLUSIONS: In the population studied, the probability of post operative survival following surgery for large intestinal disease was associated with the cardiovascular parameters heart rate and PCV on admission, age of the horse and whether it underwent resection or relaparotomy. POTENTIAL RELEVANCE: The prognosis for post operative survival for horses with large intestinal disease may be improved by early surgery, prior to the development of cardiovascular compromise. Surgeons should be aware that increasing age, resection of large colon and relaparotomy are all associated with a worsening prognosis for survival.     

Interstitial cells of Cajal (ICC) in equine colic: an immunohistochemical study of horses with obstructive disorders of the small and large intestines

REASONS FOR PERFORMING STUDY: The gastrointestinal pacemaker cells, the interstitial cells of Cajal (ICC), have been implicated in several human gastrointestinal dysmotility syndromes. Recently, the involvement of these cells in equine gastrointestinal diseases has been investigated in cases of equine grass sickness where a significant reduction in ICC density was observed. OBJECTIVE: To investigate ICC density in equine obstructive gastrointestinal disorders using immunohistochemical labelling methods. METHODS: Intestinal samples were analysed from 44 horses undergoing exploratory surgery for colic and from 11 control animals subjected to euthanasia for conditions not related to the gastrointestinal tract. Immunohistochemical labelling of ICC was carried out using an anti-c-Kit antibody. Two independent observers assessed ICC density using a semiquantitative grading system. RESULTS: There was a significant reduction in ICC density in horses with large colon disorders compared to the controls (P<0.01). Horses with strangulating lesions of the small intestine showed no difference when compared to the controls. CONCLUSIONS: There was a reduction in ICC density in horses with large intestinal disorders. POTENTIAL RELEVANCE: The reduction in ICC density may be associated with the clinical findings as well as recurrent colic episodes observed in a number of these cases. This immunohistochemical study provides a basis for future functional electrophysiological investigations to determine the precise effect of ICC reduction on equine intestinal motility.     

Packed cell volume and heart rate to predict medical and surgical cases and their short-term survival in horses with gastrointestinal-induced colic

The objective of this prospective case-control study of 125 horses with gastrointestinal tract-induced colic was to determine whether heart rate (HR) and packed cell volume (PCV) can predict surgical versus medical treatment and its short-term survival (time of discharge of the patient). Sixty-four horses were treated medically and 61 surgically (29 small intestinal and 32 large intestinal cases). At admission, both PCV and HR were higher in horses treated surgically than in horses treated medically; however, with longer duration of colic before presentation, the PCV was higher in the small intestinal surgical group only. In addition, both PCV and HR were higher, and the duration of colic was longer in non-survivors compared to survivors. Binary logistic regression demonstrated a significant association between HR and type of treatment, and both HR and PCV were predictive of survival. Simple parameters such as HR and PCV provide useful information for management of colic cases.     

Use of web-based data collection to evaluate analgesic administration and the decision for surgery in horses with colic

REASONS FOR PERFORMING STUDY: There is no current veterinary information with regard to data entry on a website. We therefore completed a prospective study on use of analgesics in relation to the need for abdominal surgery using a web-based survey instrument. OBJECTIVES: To establish an internet-based data entry system that could be used to record prospective data on horses with colic. HYPOTHESIS: Failure of horses to respond to the initial administration of an analgesic is an indicator of the need for abdominal surgery. METHODS: A survey was developed to determine if the response to administration of an analgesic during a veterinarian's first examination of a horse with colic was related to the need for surgery. Veterinarians were contacted via AAEP and ECN listservs requesting submission of cases using a log-in system at a data entry website. The survey was completed by submission of a data entry page. RESULTS: Twenty-seven veterinarians submitted details of 119 cases of colic, 28 of which required surgery. The need for surgery was significantly associated with moderate or severe pain observed during the first examination compared to mild or no pain, and with constant pain or return of pain after administration of one or more analgesics and the need to administer a second analgesic treatment. Abnormal findings on rectal examination were not associated with the need for surgery, whereas total absence or decrease of intestinal sounds was significantly related to the odds that surgery was needed. The web-based data collection was successful in collecting all data points on the survey for each case. CONCLUSIONS: This study reinforced veterinarians' use of response to therapy as a way to determine the need for abdominal surgery. POTENTIAL RELEVANCE: When a specific diagnosis has not been made, lack of response or resumption of colic after analgesic administration should be considered as an indicator of the need for surgery. Web-based collection of data allows veterinary practitioners to participate in clinical research by providing prospective data.     

Pedunculated lipomas as a cause of intestinal obstruction in horses: 17 cases (1983-1990).

The medical records of 17 horses that were evaluated and treated because of colic caused by pedunculated lipomas between 1983 and 1990 were reviewed. The mean age of the horses was 16.6 +/- 3.9 years (range, 10 to 26 years), which was significantly greater than that of the population of horses evaluated because of colic (control population) during the same period. There were significantly more geldings (76.5%), compared with the control population. Nasogastric reflux ranged from 1 to 16 L in 8 horses and was not obtained in 9 horses. Abdominal palpation per rectum revealed small intestinal distention in 13 horses, displaced large colon in 7 horses, and large colon impaction in 2 horses. Peritoneal fluid was abnormal in 11 of 12 horses from which it was obtained successfully. One horse was euthanatized after unsuccessful medical treatment. Surgery was performed in 16 horses. Lipomas were blindly resected in 5 horses or exteriorized and resected in 6 horses. The method used to resect the lipoma was not recorded in 5 horses. The ileum and/or jejunum was strangulated in 15 horses, the small colon was strangulated in 1 horse, and the jejunum was obstructed in 1 horse. The length of intestine resected ranged from 0.15 to 7.2 m. Fourteen horses survived surgery, of which 11 were discharged from the hospital (short-term survival rate of 78.6%). Excluding 2 horses lost to follow-up evaluation, 6 of 12 horses that survived surgery were alive 2 to 56 months following surgery (long-term survival rate of 50%), and 9 of 15 horses died or were euthanatized (fatality rate of 60%).     

Transrectal decompression as a new approach for treatment of large intestinal tympany in horses with colic: Preliminary results

A common feature of colic in horses is tympany in the large intestine and medical treatment of this condition can be unsuccessful. In this article we describe and evaluate a new approach for decompression of large intestinal tympany in equine colic patients using transrectal puncture. We evaluated horses showing colic symptoms and colonic or caecal tympany and the final diagnosis, complications and final outcome were recorded for each horse. A special transrectal decompression device (TDD) was developed and used to perform transrectal decompression (TD) by gas aspiration. In order to assess pain reduction as a result of TD, heart rate (HR) was recorded before and after the decompression procedure. Twenty‐five horses were included in the study. In 17 cases, tympany was recognised as primary in origin while in 8 it was secondary to other conditions. A total of 33 TDs were performed and no horses developed short‐ or long‐term complications. All horses were alive after the first month post TD, while 5 died from diseases not related to TD. The TD could safely and easily be performed in all horses presenting tympany. Transrectal decompression can easily be performed, 2 or even 3 times to treat a single colic episode by using the transrectal device connected to a surgical aspirator. It was not possible from available information to relate the timing of HR decrease to resolution of colic or to administration of drugs because a retrospective study and all such data were not readily accessible. Our clinical results support the relevance of the TD as an elective treatment of primary large intestinal tympany, emergency treatment of tympany secondary to other surgical entities and as palliative treatment in surgical patients, in which surgery could not be achieved.     

Prevalence and prognostic importance of hypomagnesemia and hypocalcemia in horses that have colic surgery

OBJECTIVE: To determine the prevalence of hypomagnesemia and hypocalcemia in horses with surgical colic. ANIMALS: 35 horses with surgically managed colic. PROCEDURE: Serum concentrations of total magnesium (tMg2+) and calcium (tCa2+), as well as ionized magnesium (iMg2+) and calcium (iCa2+) were analyzed before surgery and 1, 3, 5, and 7 days following surgery. A lead-II ECG and pertinent clinical data were also obtained at each time. RESULTS: Preoperative serum tMg2+ and iMg2+ concentrations were below the reference range in 6 (17%) and 19 (54%) horses, respectively. Serum concentrations of tCa2+ and iCa2+ were less than the reference range in 20 (57%) and 30 (86%) horses before surgery. Horses with strangulating lesions of the gastrointestinal tract had significantly lower preoperative serum concentrations of iMg2+ and iCa2+, as well as a higher heart rate than horses with nonstrangulating lesions. Horses that developed postoperative ileus had significantly lower serum concentrations of iMg2+ after surgery. Serum concentrations of magnesium and calcium (total and ionized) correlated significantly with the PR, QRS, QT, and corrected QT (QTc) intervals. Horses that were euthanatized at the time of surgery (n = 7) had significantly lower preoperative serum concentrations of iMg2+, compared with horses that survived. Neither serum magnesium nor calcium concentrations were predictors of hospitalization time or survival. CONCLUSIONS AND CLINICAL RELEVANCE: Hypomagnesemia and hypocalcemia were common during the perioperative period, particularly in horses with strangulating intestinal lesions and ileus. Serum concentrations of tMg2+ and tCa2+ were less sensitive than iMg2+ and iCa2+ in detecting horses with hypomagnesemia and hypocalcemia.