Fifty years of colic surgery

Long-term outcome after colic surgery: retrospective study of 106 horses in the USA (2014-2021)

Objective

To determine long-term survival rate, defined as survival to 1 year after discharge from the hospital, and rate of return to prior athletic, breeding, or other function in horses undergoing colic surgery at the first presentation at one referral hospital in the Pacific northwest region of the United States.

Procedures

Records were reviewed for all horses that underwent colic surgery between October 2014 and October 2021. Owners of horses that survived to discharge were contacted to obtain follow-up information via internet-based questionnaire or telephone interview. The percentage of horses that survived to 1 year after discharge, rates of return to function, and complications occurring after hospital discharge were determined. The possible association of patient signalment, lesion type, and surgical procedures with long-term survival was examined with Chi-square and Fisher's exact tests. Overall satisfaction was indicated on a scale of 1 (unsatisfied) to 5 (very satisfied).

Results

Of 185 horses that underwent surgical intervention for colic and met the inclusion criteria, 134 horses recovered from anesthesia, with 106 of these recovered horses (79.1%) surviving to discharge. Of the 71 horses for which follow-up information was obtained, 61 horses survived to 1 year after discharge (long-term survival rate of 85.9%). There were no demographic, lesion type, or surgical procedure variables significantly associated with long-term survival. Prior to surgery, 59/71 horses (83.1%) were engaged in some type of athletic activity. After surgery, 44/61 horses (72.1%) were reported to be athletically active. Only one horse was reported to be retired from athletic activity as a direct result of a complication from surgery. Overall satisfaction with the decision to proceed with colic surgery was rated by all respondents as 4 or 5.

Conclusions and clinical relevance

The long-term survival for this sample of horses was similar to previously published reports of long-term survival after colic surgery. Horses that survived to hospital discharge were highly likely to remain alive and be athletically active 1 year later. There were no factors related to the signalment of the horse, the specific cause of colic, or the surgical procedures performed that were significantly associated with likelihood of survival.

Development of a classification system for equine postoperative complications and its application in a cohort of 190 horses undergoing emergency laparotomy

BACKGROUND

Accurate reporting of postoperative complications is paramount to understanding procedural outcomes, comparing procedures and assuring quality improvement. Standardising definitions of complications in equine surgeries will improve the evidence of their outcomes. To this end, we proposed a classification for postoperative complications and applied it to a cohort of 190 horses undergoing emergency laparotomy.

METHODS

A classification system for postoperative complications in equine surgery was developed. Medical records of horses that underwent equine emergency laparotomy and recovered from anaesthesia were analysed. Reported complications pre-discharge were classified as per the new classification system, and the cost and days of hospitalisation were correlated with the equine postoperative complication score (EPOCS).

RESULTS

Of the 190 horses that underwent emergency laparotomy, 14 (7.4%) did not survive to discharge (class 6 complications), and 47 (24.7%) did not develop complications. The remaining horses were classified as follows: 43 (22.6%) had class 1 complications, 30 (15.8%) had class 2, 42 (22%) had class 3, 11 (5.8%) had class 4; and three (1.5%) had class 5. The proposed classification system and EPOCS correlated with the cost and length of hospitalisation.

LIMITATIONS

This was a single-centre study and the definition of scores was arbitrary.

CONCLUSIONS

Reporting and grading all complications will help surgeons better understand the patients' postoperative course, thereby reducing subjective interpretation.

Colic Surgery: Recent Updates

The following article provides an overview of the last 5 years of research and innovation within the field of equine colic surgery, focusing on new techniques, new or recently described lesions, prevention of lesion recurrence or postoperative complications, and updates in prognoses. Early surgical intervention is an important factor in horse survival.

Basic Postoperative Care of the Equine Colic Patient

The 3 time periods around colic surgery (preoperative, operative, and postoperative) are all critical to successful outcomes. Although much focus is often paid to the first 2 time periods, the importance of sound clinical judgment and rational decision-making in the postoperative period cannot be overstated. This article will outline the basic principles of monitoring, fluid therapy, antimicrobial therapy, analgesia, nutrition, and other therapeutics routinely used in patients following colic surgery. Discussions of the economics of colic surgery and expectations for normal return to function will also be included.

Short-Term Survival and Postoperative Complications Rates in Horses Undergoing Colic Surgery: A Multicentre Study

The occurrence of colic could be influenced by the characteristics of a population, geographical area, and feeding management. The aim of this study was to report the short-term postoperative complications and survival rates and to identify factors that might affect the outcome of horses that underwent colic surgery in three Italian surgical referral centres. Data of horses subjected to colic surgery in three referral centres (2018-2021) were analysed. Comparisons of the outcomes were performed using a Mann-Whitney or a Chi square test. Areas under the receiver operating characteristic (ROC) curve and multivariable logistic regression analysis were used for parameters that were significant in the previous univariate analysis. The goodness-of-fit of the model was assessed using the Akike information criterion (AIC). Significance was defined as p < 0.05, and odds ratios and 95% confidence intervals were calculated as percentages. A total of 451 horses were included. The survival rate was 68.5% of all of the horses that underwent colic surgery and 80% of the horses surviving anaesthesia. Age, BCS, PCV and TPP before and after surgery, amount of reflux, type of disease, type of lesion, duration of surgery, surgeon's experience, and amount of intra- and postoperative fluids administered influenced the probability of short-term survival. The multivariate analysis revealed that PCV at arrival, TPP after surgery, and BCS had the highest predictive power. This is the first multicentre study in Italy. The results of this study may help surgeons to inform owners regarding the prognosis of colic surgery.

Outcome following emergency laparotomy in 33 UK donkeys: A retrospective multicentre study

BACKGROUND

Emergency laparotomies in donkeys are infrequently performed and there is limited literature on the subject.

OBJECTIVES

To determine findings and associated outcomes of exploratory laparotomies in donkeys.

STUDY DESIGN

Descriptive retrospective study.

METHODS

Donkeys undergoing emergency exploratory laparotomy for investigation and treatment of colic at seven UK referral hospitals between 2005-2017 were included. Data were retrieved from available hospital records. Descriptive statistics and inferential statistical analysis of outcomes of interest was performed in three steps.

RESULTS

Thirty-three cases fulfilled the inclusion criteria. Clinical signs on presentation were available for 32 donkeys, of which 53.1% (17/32) presented for investigation of colic while in 46.9% (15/32) the presenting complaint was non-specific. Primary lesion location included small intestine (42.4%, 14/33), large colon (39.3%, 13/33), caecum (6.1%, 2/33), stomach (6.1%, 2/33) and 6.1% (2/33) had multiple abnormal findings without a clear primary lesion. Overall survival to discharge was 54.5% (18/33). Five donkeys (15.2%, 5/33) were euthanased at surgery and of those recovering from general anaesthesia a further 35.7% (10/28) were euthanased or died prior to discharge. Six donkeys (21.4%, 6/28) required a second laparotomy of which 4 (66.7%, 4/6) survived. Post-operative complications occurred in 82.1% (23/28) of cases and included hyperlipaemia (42.9%, 12/28), incisional complications (21.4%, 6/28), ileus (21.4%, 6/28) and persistent colic (17.9%, 5/28). When adjusted for other complications, donkeys with primary gastric lesions were less likely to have presented with severe colic compared with those with primary small intestinal lesions (OR: 0.07, 95% CI 0.01-0.95, p = 0.05). Only age was positively associated with death prior to discharge (OR: 1.18, 95% CI 1.03-1.36, p = 0.02).

MAIN LIMITATIONS

Small sample size and retrospective design.

CONCLUSION

Donkeys with abdominal lesions may present with a range of signs often not including colic. Surgical findings were diverse and survival to discharge appears to be lower than in horses.

Complications following transcutaneous cecal trocarization in horses with a cattle trocar and a cecal needle

Percutaneous decompression of the cecum is a procedure that could be considered for horses with cecal gas distension. The aim of this study was to identify complications such as peritonitis and clinically relevant peritonitis (CRP) after transabdominal cecal trocarization in healthy horses using a cattle trocar and a cecal needle. Mixed breed horses were assigned to three groups (n = 6): horses that underwent trocarization with a cecal needle (G1) or a cattle trocar (G2), and a control group (CG) without cecal trocarization. The same horses were used in each group, respecting a three-month washout period between studies. A physical examination, serial blood, and peritoneal fluid sampling were performed, prior to cecal trocarization and 2, 6 and 12 hours after the first collection and 1, 2, 3, 7, and 14 days after the procedure. Acute-phase proteins in blood and peritoneal fluid were analyzed by polyacrylamide gel electrophoresis. Horses with a high cell count in the peritoneal fluid (i.e., 10,000 cells/μl) were considered to have peritonitis and CRP if they met at least two of the following clinical criteria: anorexia, lethargy, tachycardia, tachypnea, fever, ileus, abnormal oral mucous membrane color, abnormal white blood cells count, or high blood fibrinogen concentration (> 5 g/L). All horses recovered from cecal trocarization and abdominocentesis with no major complications. Cecal trocarization caused cytologic evidence of peritonitis in G1 and G2 during the 14 days of evaluation. CRP was not observed, although a decrease in cecal motility was observed in G1 and G2 during the experimental period and three horses, one from G1 and two from G2, showed a single moment of fever. None of the groups showed leukopenia or leukocytosis, although blood neutrophil count decreased at D7 and D14 in G1 and at D14 in G2 (p ≤ 0.05). After cecal trocarization, an increase in the total nucleated cells count, total proteins, globulins, alkaline phosphatase and acute phase proteins were observed in the peritoneal fluid of G1 and G2 during the 14 days of evaluation (p ≤ 0.05), without causing clinically relevant peritonitis. Transcutaneous cecal trocarization promotes peritonitis, which is more intense with a cattle trocar than with a cecal needle. The cecal needle should be considered for cecal trocarization of horses with cecal tympany.

Retrospective Study on Risk Factors and Short-Term Outcome of Horses Referred for Colic from 2016 to 2022

Simple Summary

Colic syndrome is the most common out-of-hours call for equine practitioners. In most cases, medical treatment at home is effective for the resolution of the disorders. In 20% of cases, hospital intensive care is required. Several factors have been addressed as predisposing to the disorder. Cardiovascular and hemodynamic variables are the most reliable indicators of the severity of the condition and, thus, are important prognostic factors. The aim of the study was to highlight the predisposing factors and best prognostic clinical signs for discharge in a cohort of horses referred for colic syndrome. Medical records from 2016 to 2022 were examined. One hundred and fifty-seven horses were included in the study. Month and time of admission were the main predisposing factors. Cardiovascular variables (heart rate on admission and after 3–6 h, packed cell volume, capillary refill time, and mucosal membranes) and the presence of gastric reflux were negatively associated with discharge as well as time to standing after surgery. The results from this retrospective study may help the clinician in evaluating prognosis, deciding on the best treatment, and adequately informing the owner of the rates of success.

Abstract

(1) Background: colic syndrome is a multifactorial life-threatening condition in equids. Awareness of predisposing and prognostic indicators is useful to adequately inform the owner of the outcome and plan the best treatment. The aim of the study was to identify the variables associated with short-term survival in a cohort of horses referred for colic to a veterinary teaching hospital; (2) Methods: medical records of horses referred for colic from 2016 to 2022 were retrospectively reviewed. Univariate and multivariate regression models were built to assess the odds ratios of discharge from the hospital, both on the whole sample and in those patients undergoing surgery; (3) Conclusions: Month, time of admission, cardiovascular variables (heart rate on admission and after 3–6 h, packed cell volume, capillary refill time, and mucosal membranes), and presence of gastric reflux were significantly associated with discharge in the univariate regression in all horses and in those surgically treated. In the multivariate regression model, heart rate, packed cell volume, and capillary refill time showed significant association with the outcome in the whole sample. Although comparison between this study and previous studies is difficult due to the number and type of variables included, cardiovascular variables and markers of hypovolemia were also shown to be associated with outcome.

Performance of predictive models of survival in horses undergoing emergency exploratory laparotomy for colic

Objective

To evaluate previously published predictive survival models in a population of horses undergoing colic surgery in the midwestern United States.

Study design

Retrospective cohort study; single referral hospital.

Animals

A total of 260 horses met the inclusion criteria.

Methods

Medical records of horses undergoing surgical treatment for colic were reviewed. Previously published models were applied to cohort data to predict outcome. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for prediction of short‐term survival were calculated.

Results

Single‐variable and multivariable models performed similarly for prediction of survival, with a mean 79% sensitivity (range: 44%–94%), 48% specificity (range: 22%–83%), 63% PPV (range: 56%–72%), 73% NPV (range: 60%–83%), and 64% accuracy (range: 59%–72%). Blood lactate ≤6 mmol/l and the colic severity score (CSS) were highly sensitive for prediction of survival; however, both had poor specificity.

Conclusion

Single‐variable and multivariable predictive models did not perform as well for prediction of survival in the study cohort compared to original reports, suggesting that population‐specific factors contribute to patient survival.

Clinical significance

Predictive models of survival developed in one population may be less reliable when used to predict outcome in horses undergoing colic surgery from an independent population. Additional model testing and refinement using data from multiple surgical centers could be considered to improve prediction of outcome for horses undergoing laparotomy for treatment of colic.

Predictive Models for Equine Emergency Exploratory Laparotomy in Spain: Pre-, Intra-, and Post-Operative-Mortality-Associated Factors

The extrinsic and intrinsic characteristics of an equine population may influence the onset of gastrointestinal lesions and affect the survival rate of patients. The equine population in Spain has been the focus of a small number of studies, none of which have involved more than one surgical center. In this retrospective cohort study, we aimed to analyze the survival rate, identify the variables that influenced death, and generate multivariate models using clinical variables. Data were collected from the clinical records of two surgical referral centers in the same region, and a total of 566 horses met the inclusion criteria. The statistical analysis was divided into three parts: The first and second included logistic analysis, in order to identify the variables most closely associated with survival. The third part assessed all previous variables in terms of survival and hospitalization time, using a COX survival analysis. The main risk factors associated with intra-operative mortality were related to seasonality (winter and summer), patient age (older than 9 years), distance from the hospital, the presence of a strangulating lesion, and the bowel segment affected (small intestine). Furthermore, the main factors associated with mortality during hospitalization were the characteristics of the lesions (strangulating) and the differences between surgical centers. The models generated in this study have good predictive value and use only reliable and easily obtainable variables. The most reliable characteristics are those related to the type of colic and the location of the lesion.

Short-term survival rates of 1397 horses referred for colic from 2010 to 2018

Background

Up-to-date and hospital-specific knowledge of prognoses for horses with various forms of colic is essential for helping to guide owners’ decisions on costly treatments, and for assessing the continuous development of standards of care in the hospital. This study aimed to determine the short-term survival rates of horses admitted with colic to the University Hospital for Large Animals (UHLA), University of Copenhagen, Denmark, from 2010 to 2018, and to compare these to a previous local study as well as recent, comparable international studies.

Short-term survival rates were calculated for horses grouped by treatment (surgical, medical) and diseases. Results were compared to the selected studies using Chi-square tests.

Results

A total of 1752 horses were admitted with colic during the period, of which 355 were excluded for reasons such as economic restrictions or immediate euthanasia. Short-term survival of the remaining 1397 cases was significantly higher (83.0% (95% CI 81.1–85.0%)) than a previous local study (76%) and a recent Dutch study (80%). Medical treatment was carried out in 77.1% of cases, and surgery in 22.9% of the cases. Short-term survival for medically (89.7%) and surgically (60.6%) treated horses was significantly higher in the present study compared to the previous study (87% and 42%, respectively), but was similar to that found in the Dutch study. Significantly fewer horses were euthanised during surgery than in the previous study (17.2 vs. 40%), and significantly more horses recovered from surgery (79.1 vs. 56%). Short-term survival rate of surgically treated horses (60.6%) did not differ from other European studies (55–62%).

Conclusions

Short-term survival rates have increased since the previous study at UHLA, mainly due to a decrease in intraoperative euthanasia. Survival rates in this study are similar to those found in recent comparable colic studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13028-022-00631-4.

Effects of age, disease, and anastomosis on short- and long-term survival after surgical correction of small intestinal strangulating diseases in 89 horses

BACKGROUND

Although survival rates have been reported after small intestinal surgery for strangulating diseases in horses, none have followed survival for periods relevant to the long lifespan of horses and none have described effect of age, disease and surgical treatments over such long survival periods.

OBJECTIVES

To examine effects of age, disease, and type of surgery on long-term survival in horses after surgical treatment of small intestinal strangulating diseases over periods relevant to the expected lifespan of a horse.

STUDY DESIGN

Retrospective clinical study.

METHODS

Post-operative data were gathered from medical records and owner contact for 89 horses with small intestinal strangulation. Survival times from surgery to date of death or date of last follow-up were analysed by Kaplan-Meier statistics. Variables of interest were age, type of strangulating disease, and surgical correction. Cox proportional hazards regression was used to evaluate these variables.

RESULTS

Short-term survival was not affected by any of the variables measured. For long-term survival with Kaplan-Meier statistics, horses ≥16 years old had significantly shorter (P=0.002) median survival times (72 months; 95% C.I. 32.0-96.0) than younger horses (121.7 months; 95% C.I. 90.0-162), horses without resection had significantly longer (P=0.02) survival times (120 months; 95% C.I. 86-212) than horses that had jejunocecostomy (76.8 months; 95% C.I. 24-125), and horses with miscellaneous diseases had significantly longer (P=0.02) median survival times (161.9 months (95% C.I. 72.0-M) than horses with strangulating lipoma (79.8 months; 95% C.I. 32.0-120.0). In the multivariable Cox Proportional Hazard model, age (HR=2.67; 1.49-4.75, p<0.001) and anastomosis (HR=0.65; 0.46-0.92, P=0.02) had the most significant effect on median survival time.

MAIN LIMITATIONS

Limitations were small numbers in some categories, loss of cases to follow-up, owner recall failures, and lack of a control group.

CONCLUSIONS

The remaining lifespan of older horses at the time of surgery had the greatest effect on survival. Age could influence long-term survival studies after colic surgery, and therefore needs to be considered for survival analyses. Horses that did not require resection and anastomosis had favourable outcomes, underscoring the potential importance of early intervention to reduce the need for resection.

Comparison of liberal and goal-directed fluid therapy after small intestinal surgery for strangulating lesions in horses

BACKGROUND

There are few guidelines for the appropriate mode of fluid administration during and after colic surgery, and is challenging to reach the right balance while avoiding overhydration. This study aimed to compare goal-directed fluid therapy (GDFT) and 'liberal' fluid regimens (LFRs) in horses undergoing small intestinal surgery.

METHODS

Eighteen horses subjected to small intestinal surgery were matched according to the surgical lesion, type of anastomosis, length of resection, and duration of clinical signs. Horses in the LFR group were administered intravenous (IV) fluids for at least 24 h. In the GDFT group, IV fluids were administered only when considered necessary based on clinical parameters. Postoperative reflux (POR), packed cell volume, total protein, heart rate, venous lactate level, complications, and long-term survival rates were compared.

RESULTS

Three horses in the LFR and one in the GDFT group developed POR. Horses in the GDFT group had a shorter time interval to first oral water intake and shorter hospitalisation time. Postoperative complication rates and survival were not different between groups.

CONCLUSION

Further studies are necessary to set guidelines for the evaluation of hydration status and to plan postoperative fluid administration; however, GDFT may be a valid alternative to liberal fluid therapy after colic surgery.

Postoperative Ileus: Comparative Pathophysiology and Future Therapies

Postoperative ileus (POI), a decrease in gastrointestinal motility after surgery, is an important problem facing human and veterinary patients. 37.5% of horses that develop POI following small intestinal (SI) resection will not survive to discharge. The two major components of POI pathophysiology are a neurogenic phase which is then propagated by an inflammatory phase. Perioperative care has been implicated, namely the use of opioid therapy, inappropriate fluid therapy and electrolyte imbalances. Current therapy for POI variably includes an early return to feeding to induce physiological motility, reducing the inflammatory response with agents such as non-steroidal anti-inflammatory drugs (NSAIDs), and use of prokinetic therapy such as lidocaine. However, optimal management of POI remains controversial. Further understanding of the roles of the gastrointestinal microbiota, intestinal barrier function, the post-surgical inflammatory response, as well as enteric glial cells, a component of the enteric nervous system, in modulating postoperative gastrointestinal motility and the pathogenesis of POI may provide future targets for prevention and/or therapy of POI.

Complications associated with closure of the linea alba using a combination of interrupted vertical mattress and simple interrupted sutures in equine laparotomies

OBJECTIVES

(1) Evaluate the occurrence and variables associated with incisional morbidities (IMs) after ventral median laparotomy when using interrupted vertical mattress sutures (IVMS) and (2) determine the occurrence of abdominal bandage-associated complications in horses.

METHODS

Occurrence of IM and bandage-associated complications were determined after single laparotomies (SL group; n=546 horses) and repeat laparotomies (RL group: multiple laparotomies within four weeks; n=30 horses) in horses that survived ≥7 days postoperatively. Univariate analysis and multivariate logistic regression were performed to evaluate variables associated with IM.

RESULTS

The IM rate was 9.52 per cent in the SL group and 33.33 per cent in the RL group. The actual infection rate was 5.31 per cent in the SL group and 26.67 per cent in the RL group. Overall, long-term clinically relevant wound complications was 1.68 per cent. After multivariate analysis, increased anaesthesia duration was associated with IM and performing an enterotomy and postoperative intravenous lidocaine administration were associated with incisional infection in the SL group; no parameter remained significant in the RL group. Bandage-related complications were recorded in 2.95 per cent of the cases.

CONCLUSIONS

These results suggest that the use of IVMS for closure of the linea alba is another viable option for closure and that an abdominal bandage does not appear to cause significant complications.

In slow pace towards the proteome of equine body fluids

Equine medicine represents a relevant field of veterinary science and the horse industry generates a significant economic impact. Horses can be involved in different sport disciplines, meat production, work and recreational purposes. Horses are also important for human health as they can be used as animal models for studying human diseases and in equine-assisted therapy. This review summarizes the data related to body fluids such as plasma/serum, urine, cerebrospinal fluid, synovial fluid, saliva, bronchoalveolar lavage fluid and peritoneal fluid obtained using proteomic analysis. Horse body fluid proteome analysis under various physiological and pathological conditions is a useful method for identifying new biomarkers for horse diseases which are still difficult to diagnose, but with serious consequences on equine health and welfare. The findings reported here reveal that further proteomic studies on equine body fluids collected from diseased animals are required. SIGNIFICANCE: Body fluids are sources of potential protein biomarkers for diagnosis and therapeutic target identification. Indeed, they contain proteins that play a crucial role in cell functions and whose presence or relative abundance are indicative of the health status of tissues/organs. The review reports the data on the equine body fluids obtained using proteomic analysis, including those which are commonly used to obtain a correct diagnosis and prognosis of horse diseases which still pose a significant challenge. For equine medicine, new biomarkers are needed to formulate early diagnosis and to distinguish among diseases with similar clinical signs.

Colic Surgery in Horses: A Retrospective Study Into Short- and Long-Term Survival Rate, Complications and Rehabilitation toward Sporting Activity

Colic surgery in horses impacts both short-term well-being of horses due to possible surgical and anesthetic complications and also long-term return to a sporting career. In this retrospective study, survival and complication rates, as well as functional outcome and behavioral problems in horses that underwent colic surgery were studied. Data from 283 horses that underwent colic surgery at a veterinary teaching hospital were analyzed. Furthermore, owners were contacted and requested to fill out a questionnaire concerning the first year of rehabilitation. Of 283 horses that underwent colic surgery, 167 (59%) were discharged home. After discharge from hospital, 34 horses (12%) were lost to follow-up. Of the remaining 133 horses, 128 were still alive after 1 year (96.2%), while 5 horses were euthanized due to recurrent colic. Of the horses that did not survive the hospitalization period 73 horses (25.8%) were euthanized intraoperatively and 36 horses (12.7%) during intensive care unit (ICU) stay. Survival of horses entering the ICU up to discharge from hospital was 79.5%. During rehabilitation, 49 horses (59.8%) that returned home experienced one or more recurrences of colic. Fifty-two horses (63.4%) that returned home reached at least preoperative level of performance. Altered behavior and gait-related problems during specific elements of riding (for instance during collecting, lateral bending, etc.) were reported in up to 46.2% of horses. Improving veterinary aftercare in collaboration with other disciplines (e.g., physiotherapy and saddle fitting) during rehabilitation could be a means to further improve athletic performance and welfare after recovery from colic surgery.

Establishment of a model for equine small intestinal disease: effects of extracorporeal blood perfusion of equine ileum on metabolic variables and histological morphology - an experimental ex vivo study

BACKGROUND

In horses a number of small intestinal diseases is potentially life threatening. Among them are Equine Grass Sickness (EGS), which is characterised by enteric neurodegeneration of unknown aetiology, as well as reperfusion injury of ischaemic intestine (I/R), and post-operative ileus (POI), common after colic surgery. The perfusion of isolated organs is successfully used to minimize animal testing for the study of pathophysiology in other scenarios. However, extracorporeal perfusion of equine ileum sourced from horses slaughtered for meat production has not yet been described. Therefore the present study evaluated the potential of such a model for the investigation of small intestinal diseases in an ex vivo and cost-efficient system avoiding experiments in live animals.

RESULT

Nine ileum specimens were sourced from horses aged 1-10 years after routine slaughter at a commercial abattoir. Ileum perfusion with oxygenated autologous blood and plasma was successfully performed for 4 h in a warm isotonic bath (37.0-37.5 °C). Ileum specimens had good motility and overall pink to red mucosa throughout the experiment; blood parameters indicated good tissue vitality: 82 ± 34 mmHg mean arterial partial pressure of oxygen (pO₂) compared to 50 ± 17 mmHg mean venous pO_2, 48 ± 10 mmHg mean arterial partial pressure of carbon dioxide (pCO₂) compared to 66 ± 7 mmHg venous pCO₂ and 9.8 ± 2.8 mmol/L mean arterial lactate compared to 11.6 ± 2.7 mmol/L venous lactate. There was a mild increase in ileum mass reaching 105 ± 7.5% of the pre-perfusion mass after 4 hours. Histology of haematoxylin and eosin stained biopsy samples taken at the end of perfusion showed on average 99% (±1%) histologically normal neurons in the submucosal plexus and 76.1% (±23.9%) histologically normal neurons in the myenteric plexus and were not significantly different to control biopsies.

CONCLUSION

Extracorporeal, normothermic perfusion of equine ileum over 4 h using autologous oxygenated blood/plasma perfusate showed potential as experimental model to test whether haematogenous or intestinal exposure to neurotoxins suspected in the pathogenesis of EGS can induce neuronal damage typical for EGS. Also, this model may allow investigations into the effect of pharmaceuticals on I/R injury, as well as into the pathogenesis of equine POI.

Pressure algometry for assessment of abdominal wall sensitivity in horses after ventral midline coeliotomy

OBJECTIVE

To assess the clinical course of abdominal wall sensitivity after ventral midline coeliotomy in horses by determining mechanical nociceptive thresholds (MNTs) during hospitalization, and to determine the inter-observer reliability of pressure algometry on the abdominal wall.

STUDY DESIGN

Observational, cohort study.

SAMPLE POPULATION

A total of 13 horses presenting with signs of abdominal pain/colic undergoing ventral midline coeliotomy and 10 healthy horses without an abdominal incision.

METHODS

Measurements were performed on days 1, 3, 5, 7 and 9 postoperatively using a pressure algometer. Measurement sites were marked left and right, abaxial to the abdominal incision. Cranial to the incision, two control points were marked. Measurements were made by one observer, blinded to the recorded MNT values. To determine inter-observer reliability, five horses (surgical group n = 2; nonsurgical group n = 3) were measured by two observers in a randomized order.

RESULTS

Mean MNT values on days 5 and 7 were 9.61 Ncm^-2 and 10.14 Ncm^-2 in the operated group (p = 0.009 ; p = 0.005) respectively versus 13.00 Ncm^-2 on day 1. Wound-associated points showed lower values than control points (p = 0.002). The nonsurgical group did not show a difference between control points and wound-associated points (p = 0.06). No significant differences were found between the surgical and the nonsurgical groups at the wound-associated points on any days measured. The inter-observer reliability was low (intraclass correlation coefficient of 0.26; Cronbach's alpha of 0.27).

CONCLUSION

Operated animals showed a reduction in MNT values on days 5 and 7 when compared with day 1 and lower values for the wound-associated points when compared with the control points. Inter-observer reliability was low. Pressure algometry could be a useful tool for assessing wound sensitivity after ventral midline coeliotomy in horses, which may improve pain management postoperatively.

Evaluation of the foal survival score in a Danish-Swedish population of neonatal foals upon hospital admission

BACKGROUND

It is highly desirable to assess the probability of survival in sick neonatal foals upon admission. The foal survival score (FSS) is a published scoring system used to estimate the probability of survival in hospitalized neonatal foals <4 days old.

HYPOTHESIS/OBJECTIVES

To evaluate the ability of the FSS to predict survival in older foals from a geographically different area compared to the original study.

ANIMALS

Five-hundred ninety hospitalized neonatal foals ≤14 days of age.

METHODS

Retrospective Danish-Swedish multicenter study that included details of signalment, history, clinical examination, laboratory results, necropsy findings, and outcome. Scores and score variables were compared between survivors and nonsurvivors using logistic regression. The optimal cutoff and its test parameters were calculated using a receiver operator characteristic curve.

RESULTS

Prematurity, cold extremities, ≥2 infectious or inflammatory sites, blood glucose concentration, and total white blood cell counts were significantly associated with nonsurvival (P ≤ .02). The optimal cutoff to predict survival was ≥6, resulting in sensitivity 78%, specificity 58%, 92% positive predictive value, and 31% negative predictive value. The test performed equally well in foals <4 days old compared to those 4-14 days old.

CONCLUSIONS AND CLINICAL IMPORTANCE

Using the suggested optimal cutoff of ≥6, the FSS performed moderately well and may aid in early determination of prognosis for survival. However, the FSS did perform differently in another population and therefore should be assessed under local conditions so that its diagnostic potential is not overestimated.