One percent sodium carboxymethylcellulose prevents experimentally induced abdominal adhesions in horses

OBJECTIVE--To evaluate the efficacy of 1% sodium carboxymethylcellulose (SCMC) for prevention of experimentally induced abdominal adhesions in horses. STUDY DESIGN--Prospective, controlled, experimental study. ANIMAL POPULATION--Twelve healthy adult horses. METHODS--The effect of 1% SCMC on adhesion formation was evaluated in 12 healthy horses by using an established model of serosal trauma to induce intraabdominal adhesions. After ventral median celiotomy, 2 separate areas of the jejunum were abraded, and three 2-0 chromic gut sutures were placed in each abraded area. Jejunal resection and end-to-end anastomosis was performed at 2 sites distant to the abrasion sites. In treated horses (n = 6), 2 L of 1% SCMC was applied to the intestine before and after intestinal manipulation. In control horses (n = 6), 2 L of saline solution were applied to the intestine before and after surgical manipulation. All horses were euthanatized 10 days after surgery, and the abdominal cavity was evaluated for adhesion formation. The frequency of intraabdominal adhesions between groups was compared with a chi-square test. Statistical significance was set at P <.05. RESULTS--All control horses had intraabdominal adhesions. Fibrous adhesions were associated with both jejunal abrasion sites in 5 control horses. Fibrous adhesions were also associated with 1 or both jejunal anastomotic sites in 5 control horses. Only 1 treated horse developed adhesions at the jejunal abrasion sites, and no adhesions were present at the anastomotic sites in the treated horses. There were significantly fewer adhesions in the SCMC treatment group compared with the control group (P <.05). CONCLUSION--In this experimental model, application of 1% SCMC reduced the frequency of intraabdominal adhesions at areas of serosal abrasion and at jejunal anastomotic sites. CLINICAL RELEVANCE--In horses at an increased risk for developing intraabdominal adhesions after intestinal surgery, the use of 1% SCMC during celiotomy may decrease the frequency of adhesion formation.     

Evaluation of a bioresorbable hyaluronate-carboxymethylcellulose membrane for prevention of experimentally induced abdominal adhesions in horses

OBJECTIVE: To evaluate the efficacy of a bioresorbable hyaluronate-carboxymethylcellulose membrane (HA-membrane) for prevention of experimentally induced abdominal adhesions in horses. STUDY DESIGN: Experimental study. ANIMAL POPULATION: Twelve healthy adult horses. METHODS: The effect of an HA-membrane on adhesion formation was evaluated in 12 healthy horses using an established model of serosal trauma to induce adhesions. A ventral median celiotomy and two jejunal resections and end-to-end anastomoses were performed. Two separate jejunal areas were abraded, and three 2-0 chromic gut sutures placed in the abraded areas. In treated horses (n = 6), HA-membranes were applied to the jejunum to completely cover the anastomoses and abraded areas of jejunum. Nontreated horses (n = 6) served as controls. All horses were killed 10 days after surgery. The abdominal cavity was evaluated for adhesion formation. The frequency of intra-abdominal adhesions between groups was compared with a chi2 test with statistical significance set at P < .05. RESULTS: All control horses had intra-abdominal adhesions; fibrous adhesions were associated with both jejunal abrasion sites in 5 horses. One treated horse developed adhesions. There were significantly fewer adhesions in the HA-membrane-treated group (P < .0034). CONCLUSIONS: In this experimental model, application of an HA-membrane to a localized area of serosal trauma reduced the frequency of intra-abdominal adhesion formation. CLINICAL RELEVANCE: Application of an HA membrane may decrease the frequency of adhesions in horses at an increased risk of postoperative adhesion formation.     

Effect of carboxymethylcellulose and hyaluronate solutions on jejunal healing in horses

OBJECTIVE: To compare a double-layer inverting anastomosis with a single-layer appositional anastomosis, coated with either 1% sodium carboxymethylcellulose (SCMC) or 0.4% sodium hyaluronate (HA) solutions, in the small intestine of horses with respect to anastomotic healing and adhesion formation. ANIMALS: 18 adult horses. PROCEDURE: Midline celiotomy and end-to-end jejunal anastomoses were performed. In control group horses (n = 6), a double-layer inverting anastomosis coated with sterile lactated Ringer's solution was performed. In treatment group horses, a single-layer appositional anastomosis was performed that was coated with 1% carboxymethylcellulose solution (SAA + SCMC group horses, 6) or 0.4% hyaluronate solution (SAA + HA group horses, 6). An additional 500 mL of the respective treatment solution was applied to the jejunal serosal surface, and 2 jejunal serosal abrasion sites were created. Horses were euthanatized 10 days after surgery. Anastomoses and abdominal adhesions were evaluated grossly. Anastomotic healing was evaluated on the basis of bursting wall tension. RESULTS: Bursting wall tension was significantly greater in SAA + SCMC group horses, compared with control group horses. All intestinal segments failed at a point distant to the anastomosis. Significantly fewer adhesions were found at the abrasion sites of SAA + HA group horses, compared with control group horses. No differences were found in adhesion formation at the anastomotic sites among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Coating a single-layer appositional jejunal anastomosis with SCMC or HA solutions does not adversely affect anastomotic healing. Application of 0.4% HA solution to the serosal surface of the jejunum significantly decreases the incidence of experimentally induced intra-abdominal adhesion formation in horses.     

Ventral Abdominal Approach for Laparoscopic Cryptorchidectomy in Horses

Objective —To report a ventral abdominal approach and a ligating loop technique for laparoscopic cryptorchidectomy in horses.
Study Design —Prospective.
Sample Population—Six horses, aged 1 to 5 years, with retained testes.
Methods —One laparoscopic portal and three to four instrument portals were used for ventral abdominal laparoscopic cryptorchidectomy. Laparoscopic instruments were used to maneuver and secure the testis through a ligating loop (modified Roeder knot) that was secured from outside the abdominal cavity. Only minimal enlargement of one instrument portal was used to remove the testicle.
Results —Three horses were bilateral cryptorchids, and three were unilateral (left side, two; right side, one) cryptorchids. Operative time, defined as the time from laparoscope insertion to removal, ranged from 20 to 25 minutes for unilateral cryptorchids and from 40 to 50 minutes for bilateral cryptorchids.
Conclusions —The reported technique allowed decreased tension on the tissues during ligation and removal of the testis from the peritoneal cavity. Improved observation of the abdominal cavity, ligation security, shortened patient confinement time, and minimally invasive technique are all considered to be benefits of laparoscopic cryptorchidectomy.
Clinical Relevance —Direct observation of retained testes and intraabdominal castration are distinct advantages of the use of laparoscopy in horses that have had previous unsuccessful surgical attempts, horses with unknown histories that have retained testicular tissue, or bilateral abdominal cryptorchids.     

Laparoscopic Adhesiolysis in a Horse

Objective —The purpose of this report was to describe the use of laparoscopy as a method of treatment for abdominal adhesions in the horse.
Clinical Report —Unilateral ovariectomy for removal of a granulosa cell tumor was performed through a diagonal paramedian approach in a 14-year-old Arabian mare. Progressive incisional swelling and hemorrhage culminated in acute incisional dehiscence with herniation of ileum on the sixth postoperative day. Septic peritonitis that responded to parenteral antibiotic therapy was identified 7 days after hernia repair. Seven days later, the mare had signs of abdominal pain, and adhesions of small intestine to the paramedian incision were identified on rectal palpation. Transrectally assisted laparoscopic adhesiolysis was performed. No further complications occurred.
Clinical Relevance —Laparoscopic adhesiolysis may provide better observation of adhesions and reduced postoperative morbidity compared with laparotomy.     

Effect of Omentectomy on Adhesion Formation in Horses

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

Closed One-Stage Functional End-to-End Jejunojejunostomy in Horses With Use of Linear Stapling Equipment

Objective—To use gastrointestinal linear stapling instrumentation to perform a closed one-stage functional end-to-end jejunojejunostomy in adult horses as an alternative to a stapled side-to-side jejunojejunostomy.
Study Design—Clinical outcome, anatomic and histological architecture, and anastomotic dimensions were determined at 2, 4, 8, 16, and 24 weeks postoperatively. Animals or Sample Population—18 adult horses.
Methods—The anastomosis and peritoneal cavity were inspected for adhesions. The diameter and circumference of the anastomosis and jejunum oral and aboral to the anastomosis were determined from digitized contrast radiographs and linear measurements. Healing of anastomotic sites was evaluated histologically.
Results—Three horses were euthantized in the immediate postoperative period. In the 15 surviving horses, there were no peritoneal adhesions or distortion of the anastomoses and stomas remodeled in an end-to-end fashion. The mean anastomotic staple line (7.48 cm) and mucosa (6.89 cm) diameters were significantly ( P < .05) larger than the mean jejunal diameter oral (6.03 cm) and aboral (6.01 cm) to the anastomosis. The mean anastomotic luminal circumference (13.61 cm) was significantly ( P < .01) larger than the mean oral (11.43 cm) and aboral (11.12 cm) jejunal circumference. Histologically, there was adequate mucosal and muscularis mucosae reapposition with a moderate degree of fibrosis and inflammation.
Conclusions —Closed one-stage functional end-to-end jejunojejunostomy resulted in an acceptable functional anastomosis.
Clinical Relevance —This technique appears to be an acceptable alternative to linearly stapled, side-to-side jejunojejunostomies performed in horses.     

The Effects of Wound Lavage Solutions on Canine Fibroblasts: An In Vitro Study

Objective —The purpose of this study was to determine the effects of phosphate-buffered saline (PBS), sterile tap water, normal saline, and Ringer's lactate on wound healing in an in vitro model.
Study Design —The effects of PBS, sterile tap water, normal saline, and Ringer's lactate on a primary line of canine embryonic fibroblasts were determined.
Animals or Sample Population —A primary line of canine embryonic fibroblasts.
Methods —The effects of the various lavage solutions were determined by (1) vital staining of the treated cells with a 0.5% trypan blue solution, (2) evaluation of the amount of lactate dehydrogenase released by the treated cells, and (3) cytopathologic evaluation of hematoxylin and eosin-stained monolayers of treated canine fibroblasts. The cells were exposed to the lavage treatments for the following time intervals: 0.5 minute, 1 minute, 2.5 minutes, 5 minutes, and 10 minutes. PBS was used as the control.
Results —Sterile tap water significantly damaged canine fibroblasts at all time intervals ( P = .05). This was attributed to the alkaline pH, hypotonicity, and presence of numerous cytotoxic trace elements in the tap water used. Cytotoxic effects were noted in fibroblasts after 10 minutes' exposure to normal saline; this may be because of the acidic pH of normal saline and lack of a buffering system. Ringer's lactate did not induce any significant fibroblast injury.
Conclusions —PBS and Ringer's lactate do not induce any significant fibroblast injury, whereas normal saline and sterile tap water cause mild and severe cytotoxic effects in vitro.
Clinical Relevance —Further clinical investigation is indicated to establish whether Ringer's lactate is the wound lavage solution of choice compared with normal saline. Sterile tap water may cause considerable fibroblast injury.     

Transendoscopic Chemical Ablation of Progressive Ethmoidal Hematomas in Standing Horses

Objective —To examine the response of horses with progressive ethmoidal hematoma (PEH) to intralesional injection of 4% formaldehyde solution.
Study Design —Nasal passages of horses affected with PEH were examined endoscopically at different intervals to determine the effects of intralesional injection of formaldehyde solution.
Animals —21 horses with PEH.
Methods —PEHs were injected transendoscopically with 4% formaldehyde solution. Horses were examined endoscopically and retreated at different intervals until the PEH was eliminated or was so small that reinjection was not possible.
Results —Lesions diminished significantly in size or were eliminated after 1 to 18 injections (median, 5; mean, 7.0 ± 5.62). Seventeen lesions (60.7%) resolved completely after 1 to 18 injections (median, 5; mean, 7.2 ± 5.71). Five lesions decreased markedly in size but did not resolve after receiving 1 to 18 injections (median, 5; mean, 7.6 ± 6.66). Injection of these lesions was discontinued 4.0 to 25.1 months (median, 9.5; mean, 11.02 ± 8.446) after the first injection. The PEH of one horse was removed surgically after one injection. Three horses, one with bilateral PEH, were lost to follow-up. One horse developed signs of laminitis. No other complications were observed.
Conclusions —Horses with a PEH can be treated effectively by transendoscopic, intralesional injection of 4% formaldehyde solution.     

Use of a high-molecular-weight carboxymethylcellulose in a tissue protective solution for prevention of postoperative abdominal adhesions in ponies

OBJECTIVE: To evaluate efficacy and safety of IP administration of high-molecular-weight carboxymethylcellulose (HMW CMC) for the prevention of postoperative intra-abdominal adhesions in ponies. ANIMALS: 10 ponies. PROCEDURE: A 1% solution of HMW CMC was instilled intra-abdominally prior to surgery in 5 ponies, whereas 5 control ponies did not receive HMW CMC. Postoperative adhesions were induced by use of a bowel-abrasion method comprising laparotomy, typhlotomy, and abrasion of jejunal serosa at multiple sites with placement of 3 sutures at each site. Day of surgery was day 0. After surgery, ponies were monitored, and hematologic, serum biochemical, and peritoneal fluid analyses were performed on days 1, 2, 3, 5, 7, and 10. On day 10, ponies were euthanatized. Intra-abdominal adhesions were recorded, and tissue samples were collected for histologic examination. RESULTS: A significantly greater number of adhesions, number of multiple adhesions, and mean incidence of adhesions were identified in control ponies, compared with CMC-treated ponies. Mean peritoneal fluid WBC count on day 7 and serum fibrinogen concentrations on days 5 and 7 were significantly higher in control ponies, compared with CMC-treated ponies. Results of serum biochemical analyses did not differ significantly between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: Intra-abdominal use of 1% HMW CMC during surgery was effective for preventing postoperative adhesions in ponies. Use of HMW CMC did not have detrimental effects on wound healing, intra-abdominal defenses, or patient health. A 1% solution of HMW CMC may be used routinely during abdominal surgery of horses for prevention of postoperative adhesions.     

A Modified Technique for Extensive Large Colon Resection and Anastomosis in Horses

Objective —To describe an alternative technique for large colon resection and anastomosis in horses.
Study Design —Retrospective study of clinical patients.
Animal Population —37 horses that had ventral midline celiotomies between July 1, 1990, and July 1, 1994.
Methods —Large colon resection and anastomosis was performed using a modification of previously described techniques. Modifications include mesocolon ligation with a stapling device and an end-to-end apposition of the right ventral and right dorsal colon.
Results —Twenty-one of the 37 horses were discharged from the hospital without complications. Two horses were euthanatized immediately after recovery from anesthesia because of hindlimb fracture. Fourteen horses were euthanatized in the initial postoperative period because of persistent endotoxemia and abdominal pain.
Conclusions —The described technique is a safe, reliable method for large colon resection and anastomosis in horses.
Clinical Relevance —The described technique is fairly simple to perform and requires less surgical time compared with other techniques.     

Incomplete Oblique Sagittal Fractures of the Dorsal Cortex of the Third Metacarpal Bone in Six Horses

Objective —To describe incomplete oblique sagittal dorsal cortical fractures of the equine third metacarpal bone, their surgical repair, and subsequent performance of the horses.
Study Design —Retrospective examination of medical records and racing performance.
Animal Population —Six Thoroughbred race horses, 2 to 4 years of age.
Methods —Radiographic confirmation of all fractures preceded general anesthesia and surgical correction. Three fractures were treated by intracortical compression using screws placed in lag fashion, and five fractures were treated by osteostixis. Race records were reviewed for each horse to determine performance after surgery.
Results —Fractures were best observed on palmarodorsal radiographic projections. Three horses treated by intracortical compression returned to racing, but fracture recurred in one horse and was treated by osteostixis. This horse and the other three horses treated by osteostixis raced after surgery.
Conclusions —Horses with incomplete oblique sagittal fractures of the dorsal cortex of the third metacarpal bone can race after surgical management of the fracture by screws placed in lag fashion or osteostixis. The authors' preferred surgical procedure for managing this fracture is osteostixis.
Clinical Relevance —Palmarodorsal radiographic projections of the third metacarpal bone are recommended in young Thoroughbred race horses suspected of having dorsal metacarpal stress fractures.     

Laparoscopic Cryptorchidectomy in Standing Horses

Objective — The purpose of this study was to determine the feasibility of using laparoscopy to remove cryptorchid testes from standing horses.
Study Design — Prospective clinical study.
Animals or Sample Population — Eleven client-owned horses ranging in age from 4 months to 2 years.
Methods — Abdominal insufflation was initiated and maintained using a 20 F insufflation tube, attached via a stopcock, to the low pressure regulator on a standard carbon dioxide pressure tank. After trocar and laparoscope placement in the ipsilateral flank the testes were identified. Local anesthesia of the structures to be manipulated was administered through the instrument channel on the operative laparoscope, using a catheter with a needle attached. Testes were grasped with large laparoscopic forceps and exteriorized through the abdominal wall. Ligation and transection of the mesorchium was extracorporeal. The descended testes were removed using a standard standing technique.
Results — Complications were minor, including mild colic in one horse. The mean surgical time for standing laparoscopic cryptorchidectomy and castration of these colts was 58.9 ±24.3 minutes.
Conclusions and Clinical Relevance — Standing laparoscopic cryptorchidectomy, using the instrumentation described, is a safe and practical technique in young horses.     

Evaluation of laparoscopic adhesiolysis for the treatment of experimentally induced adhesions in pony foals

OBJECTIVE: To assess the efficacy of laparoscopic adhesiolysis in the treatment of experimentally induced adhesions in foals. ANIMALS: 8 healthy pony foals. PROCEDURE: Celiotomy was performed and adhesions created at the jejunoileal junction and at sites 0.5 and 1 m proximal to this junction, using a serosal abrasion method. Ten days after celiotomy, exploratory laparoscopy was performed. Laparoscopic adhesiolysis was performed in the treatment group only (4 foals, randomly selected). Thirty days after the exploratory laparoscopy, a final laparoscopic examination was performed, and the foals were euthanatized. The number and characteristics of abdominal adhesions were recorded during laparoscopy 10 and 30 days after celiotomy and during necropsy. RESULTS: At 30 days after celiotomy, the number of adhesions in the control group was significantly higher than the number in the treatment group. In the control group, all adhesions observed during the exploratory laparoscopy were still evident at the final laparoscopy and necropsy. In the treatment group, adhesions did not form again after separation. During final laparoscopy and necropsy, a focal adhesion between the omentum and site of the initial laparoscope portal was observed in 5 of 8 foals. CONCLUSIONS AND CLINICAL RELEVANCE: The serosal abrasion model is useful for studying abdominal adhesions in foals. Laparoscopic adhesiolysis was an effective technique to break down experimentally induced adhesions in the early maturation stage of formation in pony foals. Studies are required to investigate prevention of de novo adhesions at the laparoscope portal sites.     

Effect of carboxymethylcellulose and a hyaluronate-carboxymethylcellulose membrane on healing of intestinal anastomoses in horses

OBJECTIVE: To evaluate the effect of sodium carboxymethylcellulose (SCMC) or a hyaluronate-carboxymethylcellulose membrane (HA membrane) on healing of the small intestine in horses. ANIMALS: 18 healthy adult horses. PROCEDURE: Midline celiotomy and 2 jejunal resection-and-anastomosis surgeries were performed. In treated horses, SCMC (n = 6) or a HA membrane (6) was applied to the jejunum to cover the anastomosis. There were 6 untreated control horses. Horses were euthanatized 10 days after surgery. For each horse, 1 anastomosis was used for histologic examination, and the second was used to determine intestinal bursting strength. Intestinal bursting tension, serosal granulation tissue, serosal fibrin deposition, and width of the fibrous seal at the anastomosis were compared among groups. RESULTS: 3 control horses had adhesions associated with the anastomosis, but none of the treated horses had adhesions associated with the anastomosis. Mean thickness of fibrin deposited on the serosal surfaces for the SCMC and HA-membrane groups was significantly less than that for control horses. Mean thickness of serosal granulation tissue, width of fibrous seal between inverted musculature, inflammatory cell infiltrate scores, and bursting tension did not differ significantly among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Use of SCMC or application of a HA membrane to small intestinal anastomoses in horses resulted in fewer adhesions and decreased fibrin deposition, and it did not adversely affect anastomotic healing. In horses at increased risk for intra-abdominal adhesions, SCMC or application of HA membranes may decrease the frequency of adhesions without adversely affecting healing of small intestinal anastomoses.     

Use of an active intra-abdominal drain in 67 horses

OBJECTIVE: To describe the insertion technique, efficacy, and complications associated with the use of an active (closed-suction) abdominal drain in horses. STUDY DESIGN: Retrospective study. Animals-Sixty-seven horses with abdominal contamination treated by abdominal lavage and use of a closed-suction abdominal drain. METHODS: Medical records of horses (1989-1996) that had a closed-suction abdominal drain were reviewed. Follow-up information was obtained by telephone interviews with owners. RESULTS: Sixty-eight closed-suction abdominal drains were used in 67 horses that had abdominal contamination, peritonitis, or to prevent adhesion formation. The drain was placed under general anesthesia (62 horses) or in a standing position (6 horses). Abdominal lavage was performed every 4 to 12 hours and about 83% of the peritoneal lavage solution was retrieved. Minor complications associated with drain use occurred in 49% of the horses and included obstruction or slow passage of fluid through the drain in 18 horses (26%), leakage of fluid around the drain in 11 horses (16%), and subcutaneous fluid accumulation around the drain in 8 horses (12%). Incisional suppuration developed in 20 of 62 (32%) and incisional herniation in 5 of 46 (11%) horses. CONCLUSIONS: A closed-suction drain system was easily placed and was associated with only minor complications in most horses. CLINICAL RELEVANCE: Active abdominal drainage and lavage is a useful adjunct in the treatment of peritonitis or as a prophylactic procedure in horses at risk of developing septic peritonitis and abdominal adhesions. Clinicians should be aware of the high incidence of minor complications.     

Effects of Carolina rinse solution, dimethyl sulfoxide, and the 21-aminosteroid, U-74389G, on microvascular permeability and morphology of the equine jejunum after low-flow ischemia and reperfusion

OBJECTIVE: To evaluate effects of Carolina rinse solution, dimethyl sulfoxide (DMSO), and 21-aminosteroid, U-74389G, on microvascular permeability and morphology of the equine jejunum after low-flow ischemia and reperfusion. ANIMALS: 20 healthy adult horses. PROCEDURE: Under anesthesia, full-thickness biopsy specimens of a distal portion of the jejunum were obtained for baseline measurements. In addition to a control segment, 2 jejunal segments were identified as sham-operated or experimental segments. Experimental segments underwent 60 minutes of low-flow ischemia and 3.5 hours of reperfusion. Treatments were as follows: U-74389G (3 mg/kg, IV; 6 horses), DMSO (20 mg/kg, IV; 6) diluted in 1 L of saline (0.9% NaCl) solution, local perfusion (via jejunal artery) of Carolina rinse solution (0.5 mL/kg; 4), and local perfusion of lactated Ringer's solution (0.5 mL/kg; 4). RESULTS: Jejunal microvascular permeability was significantly lower after treatment with Carolina rinse solution or DMSO, compared with U-74389G or lactated Ringer's solution treatments. After DMSO treatment, serosal- and submucosal-layer edema was significantly increased in experimental segments, compared with control or sham-operated segments; however, edema increases were significantly less than for lactated Ringer's solution or U-74389G treatments. Significant decreases in intestinal wet weight-to-dry weight ratio were found following Carolina rinse solution or DMSO treatments, compared with lactated Ringer's solution or U-74389G treatments. Edema formation and leukocyte infiltration in jejunal segments of horses treated with lactated Ringer's solution or U-74389G were increased, compared with Carolina rinse solution or DMSO treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Carolina rinse solution and DMSO may be protective against ischemia-reperfusion injury in the equine jejunum.     

Peritoneal lavage in the horse.

Eight horses ranging in age from 4 days to 9 years were treated for peritonitis. Escherichia coli was isolated in four cases and Nocardia sp in one case. In each case, a catheter placed in the peritoneal cavity allowed drainage of a large amount of purulent fluid. Retrograde peritoneal lavage was performed through a Foley catheter or medical tubing, using Ringer's lactate solution containing kanamycin, povidone iodine, or nitrofurazone. All except two horses responded well to repeated lavage.     

Fibrinolytic Responses of the Equine Peritoneum to Abdominal Surgery,Surgical Trauma,and Intraperitoneal Sodium Hyaluronate

Postoperative abdominal adhesions are known to present clinical challenges to the surgeon. Adhesion formation is a balance modulated by the fibrinolytic system. The key components involved are the tissue plasminogen activators (tPAs) and plasminogen activator inhibitors (PAI-1 and PAI-2). Sodium hyaluronate (HA) has been shown to reduce the incidence and severity of adhesions in horses. The objectives of this study were to measure tPA and PAI-1 activity in equine peritoneum and evaluate the effect of 0.4% HA solution on local tPA and PAI-1 activity. An exploratory laparotomy was performed and local serosal trauma was induced by using an established abrasion model. Our study involved two groups: in the first group (n = 6) 0.4% HA was used in all intestinal manipulations, whereas in the second group (n = 6) sterile saline was used. Parietal peritoneum, jejunal seromuscular biopsies at abraded sites (AJ) and nonabraded sites, and peritoneal fluid samples were taken at time 0- and at 30-minute intervals up to 120 minutes. Peritoneum tPA activity was significantly decreased at 60 and 90 minutes. Interestingly, AJ contained significantly higher tPA activity than nonabraded sites at 30-, 60-, 90-, and 120-minute intervals in control horses. The increase in tPA activity with AJ in treated (HA) horses was significantly attenuated as compared with the control (saline). Detectable levels of PAI-1 activity could not be identified in our samples. The results of our study indicate that exploratory celiotomy in horses is associated with a significant decrease in peritoneal tPA activity, and HA significantly decreases the fibrinolytic response of the jejunum to surgical trauma. Further characterization of these responses will hopefully lead to new pharmacologic strategies for adhesion prevention.