Intrathoracic esophageal perforation of unknown cause in four horses

Three horses (age 17 - 23 years) were referred to the equine clinic of the University of Berne due to colic, fever, tachycardia and tachypnea. All horses showed pleural effusion. Clinical findings in 2 of the horses were highly suggestive of an intra-thoracic esophageal perforation. Severe septic pleuropneumonia without suspicion of an esophageal lesion was diagnosed in the 3rd horse. In addition, an 11 year old stallion was referred to the equine clinic for treatment of a presumptive large colon impaction. The horse was given laxatives after nasogastric intubation. Subsequent dramatic clinical deterioration and signs consistent with severe pleuropneumonia suggest that esophageal perforation had occurred when passing the nasogastric tube. All 4?horses were euthanized due to a poor prognosis. Esophageal perforation was diagnosed or confirmed post mortem in all cases. A hypertrophy of the tunica muscularis of the intra-thoracic esophagus was found in 3 of 4?horses.     

Arytenoid mucosal injury in young Thoroughbred horses--investigation of a proposed aetiology and clinical significance

AIM: To determine whether trauma to the larynx caused by nasotracheal intubation induced mucosal ulceration of the arytenoid cartilages of adult horses, and to determine the incidence of such ulceration in yearling Thoroughbred horses and its effect on athletic performance. METHODS: Laryngeal trauma was induced in a group of 21 adult horses by introduction of a nasogastric tube into the trachea three times within 5 min. Injury to the arytenoid cartilages or vocal cords was subjectively assessed immediately after intubation, and thereafter at weekly intervals for 10 weeks. The outcome and athletic performance of 33 Thoroughbred yearling horses with idiopathic disease of the arytenoid cartilages, diagnosed at the yearling sales, were evaluated and compared to those of control horses of the same gender and age, from the same sale. RESULTS: Mucosal injury was noted immediately after intubation in every horse. Evidence of injury to the vocal or corniculate processes of the arytenoid cartilages or vocal cords was still apparent in 10/21 (48%) horses 1 week after intubation, five of which developed persistent lesions that remained present and unchanged from 28 days following intubation until the end of the 10-week observation period. All persistent lesions were nodules or focal swellings of the vocal cords or arytenoid cartilages, and there was no evidence of mucosal ulceration, infection or discharge. Mucosal ulceration of the vocal processes was the most common abnormality detected in the yearlings, affecting 16/33 (48%) that were diagnosed with idiopathic arytenoid disease at the yearling sales. Five of the 33 (15%) horses were diagnosed with arytenoid chondritis at the time of sale and were excluded from the performance outcome analysis. Of the 28 horses diagnosed with arytenoid abnormalities excluding chondritis, 19 (68%) raced with no history of respiratory-related problems, two (7%) were subsequently diagnosed with laryngeal hemiplegia, and seven (25%) were lost to follow-up. The case animals were 2.7 times more likely to race than control horses, but there was no difference between cases and controls in the likelihood of starting more than three times. CONCLUSIONS: This study showed that nasotracheal intubation in adult horses could result in immediate mucosal trauma, persistent swelling, and focal scarring of the arytenoid cartilages, but this did not mimic mucosal ulceration or chondritis of the arytenoid cartilages observed in yearling Thoroughbred horses. The population studied, however, may not accurately represent the population in which idiopathic disease occurs. In this study, arytenoid mucosal ulceration detected at sale did not commonly progress to arytenoid chondritis. However, a study of a larger population of horses with untreated, naturally occurring disease is required to confirm these findings. CLINICAL RELEVANCE: It is unlikely that trauma from nasogastric intubation caused arytenoid mucosal ulceration, therefore this procedure should not necessarily be discouraged. This study did not find evidence that horses diagnosed with arytenoid mucosal ulceration at yearling sales had a reduced performance history, therefore it is reasonable to continue to pass horses with uncomplicated arytenoid mucosal ulceration during post-sale endoscopic examination. However, monitoring of the lesions and treatment, if required, may be indicated in the post-sale period.     

Laryngotracheal injury associated with nasotracheal intubation in the horse

Laryngotracheal damage following short-term nasotracheal intubation was studied in 7 healthy horses. A flexible fiberoptic endoscope was used to examine the upper respiratory tract of each horse before nasal intubation with a cuffed silicone endotracheal tube and again at 1 hour, 24 hours, and 48 hours after extubation. Any abnormalities still evident at 48 hours were evaluated at 7 days after extubation. Mucosal damage involved the nasal meatus (5 of 7 horses), the arytenoid cartilages (5 of 7 horses), the trachea (5 of 7 horses), the dorsal pharyngeal recess (4 of 7 horses), the vocal folds (3 of 7 horses), and the entrance to the guttural pouch (3 of 7 horses). Laryngeal injury was attributable to tube pressure on the arytenoid cartilages and vocal folds. Tracheal damage appeared to be a function of pressure exerted by the inflated cuff on the tracheal mucosa.     

Effects of indwelling nasogastric intubation on gastric emptying of a liquid marker in horses

OBJECTIVE: To determine the effects of indwelling nasogastric intubation on the gastric emptying rate of liquid in horses. ANIMALS: 6 healthy horses. PROCEDURES: Horses were assigned to treatment and control groups in a prospective randomized crossover study with a washout period of at least 4 weeks between trials. Acetaminophen (20 mg/kg) diluted in 1 L of distilled water was administered via nasogastric tube at time points of 0, 12, 30, 48, and 72 hours to evaluate the liquid-phase gastric emptying rate. In control horses, nasogastric tubes were removed after administration of acetaminophen. In horses receiving treatment, the tube was left indwelling and maintained for 72 hours. A 10-mL sample of blood was collected from a jugular vein immediately before and 20, 40, 60, 80, 100, 120, and 180 minutes after acetaminophen administration. Serum acetaminophen concentrations were measured by use of a colorimetric method. RESULTS: Peak serum acetaminophen concentration was significantly higher in the control group (38.11 microg/mL) than in the treatment group (29.09 microg/mL), and the time required to reach peak serum acetaminophen concentration was significantly shorter in the control group (22.79 minutes) than in the treatment group (35.95 minutes). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that indwelling nasogastric intubation has a delaying effect on the gastric emptying rate of liquids. Veterinarians should consider the potential for delayed gastric emptying when placing and maintaining an indwelling nasogastric tube for an extended period of time after surgery. Repeated nasogastric intubation may be better than maintenance of an indwelling tube in horses with ileus.     

Neutrophil myeloperoxidase measurements in plasma, laminar tissue, and skin of horses given black walnut extract

OBJECTIVE: To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE). ANIMALS: 22 healthy 5- to 15-year-old horses. PROCEDURES: Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Plasma samples were obtained hourly for all horses. Laminar tissue and skin from the middle region of the neck were harvested at the time of euthanasia. Plasma and tissue MPO concentrations were determined via an ELISA; tissue MPO activity was measured by use of specific immunologic extraction followed by enzymatic detection. RESULTS: Tissues and plasma of horses receiving BWHE contained significantly higher concentrations of MPO beginning at hour 3. Laminar tissue and skin from horses in experimental groups contained significantly higher MPO activity than tissues from control horses. Concentrations and activities of MPO in skin and laminar tissues were similar over time. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.     

Comparison of three feeding techniques after esophageal mucosal resection and anastomosis in the horse

The effects of 3 feeding techniques on healing of a cervical esophageal mucosal resection and anastomosis were investigated in 16 horses. Horses were fed a moistened pelleted diet 1 of 3 ways: 1) per os (n = 5), 2) by nasogastric (n = 5) or 3) by esophagostomy tube (n = 6) until the 14th postoperative day. The pelleted diet was then fed orally in all horses until euthanasia on the 60th postoperative day. Immediate postoperative feeding per os was unsatisfactory, as only 2 of 5 horses survived in this group. Endoscopic evaluation revealed that mucosal dehiscence of varying degrees occurred, with subsequent stricture formation in all horses. Although the incidence of some complications (fistula, sinus tract and traction diverticulum) was higher in the nasogastric tube-fed horses, 2 of 6 horses in the esophagostomy tube-fed group did not survive to the end of the study. There was more cervical phlegmon in the esophagostomy tube-fed group, and this resulted in increased periesophageal fibrosis on histopathologic examination. Radiographic measurements showed that esophageal lumen diameter increased predominantly between 30 and 45 days postoperatively. The mucosal healing time was significantly faster (p = 0.05) in the esophagostomy tube-fed group.     

Effect of an indwelling nasogastric tube on gastric emptying rates of liquids in horses

OBJECTIVE: To evaluate the effect of an indwelling nasogastric tube on gastric emptying of liquids in horses. ANIMALS: 9 healthy adult horses. PROCEDURE: A randomized block crossover design was used. For treatment group horses, a nasogastric tube was placed and 18 hours later, acetaminophen was administered; the nasogastric tube remained in place until the experiment was complete. For control group horses, a nasogastric tube was passed into t stomach, acetaminophen was administered, and the nasogastric tube was removed immediately. Serial blood samples were collected 15 minutes before and after administration of acetaminophen. Serum concentration of acetaminophen was determined by use of fluorescence polarization immunoassay. The variables, time to maximum acetaminophen concentration (Tmax) and the appearance constant for acetaminophen (Kapp), were determined. The values for Kapp and Tmax in horses with and without prolonged nasogastric tube placement were compared. RESULTS: No significant difference was found in Kapp between horses with and without prolonged nasogastric tube placement; the median difference in Kapp was 0.01 min(-1) (range, -0.48 to 0.80 min(-1). No significant difference was found in Tmax between horses with and without prolonged nasogastric tube placement; the median difference in Tmax was 5 minutes (range, -30 to 50 minutes). Reanalysis of data following the removal of possible outlier values from 1 horse resulted in a significant difference in Tmax between horses with and without prolonged nasogastric tube placement. CONCLUSIONS AND CLINICAL RELEVANCE: Although no clinically important impact of 18 hours of nasogastric intubation was found on gastric emptying in healthy was found among horses.     

Effects of treatment with oxytocin,xylazine butorphanol,guaifenesin, acepromazine,and detomidine on esophageal manometric pressure in conscious horses

OBJECTIVE: To compare effects of oxytocin, acepromazine maleate, xylazine hydrochloride-butorphanol tartrate, guaifenesin, and detomidine hydrochloride on esophageal manometric pressure in horses. ANIMALS: 8 healthy adult horses. PROCEDURE: A nasogastric tube, modified with 3 polyethylene tubes that exited at the postpharyngeal area, thoracic inlet, and distal portion of the esophagus, was fitted for each horse. Amplitude, duration, and rate of propagation of pressure waveforms induced by swallows were measured at 5, 10, 20, 30, and 40 minutes after administration of oxytocin, detomidine, acepromazine, xylazine-butorphanol, guaifenesin, or saline (0.9% NaCI) solution. Number of spontaneous swallows, spontaneous events (contractions that occurred in the absence of a swallow stimulus), and high-pressure events (sustained increases in baseline pressure of > 10 mm Hg) were compared before and after drug adminision. RESULTS: At 5 minutes after administration, detomidine increased waveform amplitude and decreased waveform duration at the thoracic inlet. At 10 minutes after administration, detomidine increased waveform duration at the thoracic inlet. Acepromazine administration increased the number of spontaneous events at the thoracic inlet and distal portion of the esophagus. Acepromazine and detomidine administration increased the number of high-pressure events at the thoracic inlet. Guaifenesin administration increased the number of spontaneous events at the thoracic inlet. Xylazine-butorphanol, detomidine, acepromazine, and guaifenesin administration decreased the number of spontaneous swallows. CONCLUSIONS AND CLINICAL RELEVANCE: Detomidine, acepromazine, and a combination of xylazine butorphanol had the greatest effect on esophageal motility when evaluated manometrically. Reduction in spontaneous swallowing and changes in normal, coordinated peristaltic activity are the most clinically relevant effects.     

Use of a nasogastric tube for gastric and esophageal decompression in the dog and cat

Distension of the stomach with air and fluid was treated successfully in 9 of 10 dogs by use of an indwelling nasogastric tube. A nasogastric tube was used to remove swallowed air and gastric fluid after surgery, as a precautionary measure to prevent recurrence of gastric distention in 2 dogs. A nasoesophageal tube was used to remove retained barium sulfate and saliva in a cat with megaesophagus and esophageal obstruction caused by gastroesophageal intussusception. Passage of the tube through the nose into the esophagus or stomach was easily accomplished in 10 of the 13 animals, requiring only mild restraint and an anesthetic instilled locally into the nostril. Moderate restraint and more than one attempt at passage of the tube through the nose (ventral meatus) were required in the other 3 animals. In one of these, passage through the ventral meatus and into the pharynx could not be accomplished. Of the 12 animals in which the tube was inserted successfully, 11 tolerated it. The tubes remained inserted from 5 minutes to 48 hours (average, 18.5 hours) without clinically detected complications. This technique offers an alternative to orogastric, gastrostomy, or pharyngostomy tubes for initial and continuous intubation and decompression of the stomach and/or esophagus in the dog and cat. It was found to be practical and effective for the removal of air or fluid, but not the removal of coarse food particles.     

Laryngotracheal lesions following routine orotracheal intubation in the horse

Sequelae of routine orotracheal intubation under clinical conditions were characterised in 38 healthy horses presented at three veterinary medical teaching hospitals. Four of these were necropsied and their tissues studied histologically. To minimise variation, 30 mm id cuffed silicone endotracheal tubes or Cole cuffless tubes were used in all patients. Fibreoptic endoscopic examination of upper respiratory and tracheal areas was accomplished pre-intubation, immediately post extubation and after 24 h. Endoscopy revealed that intubation was associated with laryngeal and/or tracheal lesions in all horses. Observations included abundant tracheal mucus, epithelial ecchymoses, basement membrane haemorrhage and mucus covered diphtheritic membrane plaques. Histological examination of lesions from the upper respiratory system of the four necropsied horses confirmed that the damage was comparable to that associated with tracheal intubation and reported in other species.     

Esophageal obstruction in horses: a retrospective study of 34 cases

The major purpose of this investigation was to describe the causes, possible complications, and prognoses of horses with esophageal obstruction. Of 34 cases presenting with esophageal obstruction, 28 cases were due to impaction of ingesta. Obstruction due to pre-existing esophageal disease occurred in 4 horses with megaesophagus, in 1 horse with stricture in the upper third of the esophagus, and in 1 horse with esophageal diverticulum. There was no significant difference in the contamination of the trachea between horses that subsequently developed aspiration pneumonia and those that did not. The duration of esophageal obstruction prior to admission was significantly longer in horses that developed aspiration pneumonia (median 18, range 2-48 h) than in those horses that did not (median 4, range 0.5-48 h). Although the obstruction was relieved in all 34 horses, 4 were euthanized because of recurring obstruction due to megaesophagus (n = 2), esophageal diverticulum (n = 1), and esophageal stricture (n = 1).     

Evaluation of urine sucrose concentration for detection of gastric ulcers in horses

OBJECTIVE: To evaluate the use of sucrose permeability testing to detect ulcers in the gastric squamous mucosa of horses. ANIMALS: 13 adult horses ranging from 5 to 19 years of age. PROCEDURE: Following induction of gastric ulcers by intermittent feed deprivation, horses underwent sucrose permeability testing (administration of sucrose by nasogastric intubation followed by collection of urine at 2 and 4 hours after intubation) and gastric endoscopy. Squamous ulcers were assigned a severity score (range, 0 to 3) by use of an established scoring system. Horses were subsequently administered omeprazole for 21 days, and sucrose testing and endoscopy were repeated. Pair-wise comparisons of urine sucrose concentration were made between horses with induced ulcers before and after omeprazole treatment. Urine sucrose concentrations also were compared on the basis of ulcer severity score. RESULTS: Urine sucrose concentrations and ulcer severity scores were significantly higher in horses with induced ulcers before omeprazole treatment than after treatment. Urine sucrose concentrations were significantly higher for horses with ulcer severity scores > 1. Use of a cut-point value of 0.7 mg/mL revealed that the apparent sensitivity and specificity of sucrose permeability testing to detect ulcers with severity scores > 1 was 83% and 90%, respectively. Results were similar after adjusting sucrose concentrations for urine osmolality. CONCLUSIONS AND CLINICAL RELEVANCE: Urine sucrose concentration appears to be a reliable but imperfect indicator of gastric squamous ulcers in horses. Sucrose permeability testing may provide a simple, noninvasive test to detect and monitor gastric ulcers in horses.     

Removal of nasogastric tube fragments from three horses.

Three horses were admitted for retrieval of polyurethane nasogastric tube fragments. The fragments were removed from the esophagus or stomach of 2 horses by manipulation of a snare introduced through the biopsy port of an endoscope. The fragments were surgically removed from the stomach of the third horse.     

Surgical Treatment of Intramural Esophageal Inclusion Cysts in Three Horses

Three horses were diagnosed as having esophageal inclusion cysts. Clinical signs included dysphagia, swelling of the cervical esophagus, and salivation. Surgical removal of the cyst was attempted in two horses. Both horses survived, but multiple complications occurred, including esophageal fistulation and neurovascular damage. Marsupialization of the cyst was performed in the third horse. The stoma closed 3 weeks after surgery without complications, and endoscopic examination revealed a grossly normal esophagus. Marsupialization may be preferable to surgical removal for treatment of selected esophageal inclusion cysts in horses.     

Bypass Surgery for the Treatment of Small Intestinal Ileus in the Horse A Report of Three Cases

The medical management of three horses with simple and strangulating small intestinal obstructions was unsuccessful and was therefore supported by surgical bypasses. Jejunocecostomies were used to treat horses with postoperative paralytic ileus that was unresponsive to medical management. These horses had abdominal pain, gastric distention, heart rate elevations greater than 60/minute, and small intestinal distention on rectal palpation. Two horses experienced weight loss which responded to bypass removal. The bypass effectively decreased the need for intravenous fluid administration and repeated nasogastric intubation.     

Esophageal manometry in horses, cows, and sheep during deglutition

Esophageal pressure events during deglutition were evaluated in healthy adult animals (6 horses, 6 cattle, and 5 sheep), using a 3-side hole catheter assembly perfused with water by use of a hydraulic-capillary infusion system. The peak postdeglutition pressure, contraction time, and contraction length were determined for the cranial and caudal esophageal sphincter regions and for each functionally different region within the body of the esophagus. The percentage of deglutitions in which relaxation developed at the sphincter regions and the propagation speed (velocity at which pressure waves traversed the esophagus) for the regions within the body of the esophagus also were determined. Mean (+/- SEM) resting pressures within the cranial and caudal esophageal sphincter regions in the horse were 84.8 +/- 4.39 and 12.7 +/- 0.61 mm of Hg, respectively, with postdeglutition peaks of 208.0 +/- 4.78 and 100.0 +/- 1.06 mm of Hg, respectively. Peak postdeglutition pressure was 92.3 +/- 1.59 mm of Hg in the cranial two thirds of the esophageal body and 100.9 +/- 1.31 mm of Hg in the caudal third. Mean resting pressure of the cranial esophageal sphincter region in the cow was 82.0 +/- 7.81 mm of Hg, whereas that of the caudal esophageal sphincter region was 20.5 +/- 0.36 mm of Hg. The peak postdeglutition pressures for the cranial esophageal sphincter region, proximal portion of the esophageal body, caudal portion of the esophageal body, and caudal esophageal sphincter region in the bovine esophagus were 238.1 +/- 2.93, 105.4 +/- 1.97, 114.5 +/- 1.49, and 112.0 +/- 1.20 mm of Hg, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Early laminar events involving endothelial activation in horses with black walnut- induced laminitis

OBJECTIVE: To determine proinflammatory gene expression, endothelial adhesion molecule gene expression, and matrix metalloproteinase (MMP) concentrations in laminar specimens at 1.5 hours after administration of black walnut extract (BWE) and to compare these values with later time points. ANIMALS: 25 horses. PROCEDURES: After nasogastric administration of BWE, anesthesia was induced at 1.5 hours in early time point (ETP) horses (n = 5), between 3 and 4 hours in developmental time point horses (5), and between 9 and 10 hours in acute onset of lameness time point horses (5). Anesthesia was induced at 3 and 10 hours after nasogastric administration of water in 2 groups of control horses (3-hour control group, n = 5; 10-hour control group, 5). Real-time quantitative PCR assay was performed on laminar specimens from control and ETP horses for cyclooxygenase (COX)-1, COX-2, interleukin (IL)-1beta, tumor necrosis factor-alpha, IL-6, IL-8, IL-10, MMP-2, and MMP-9 gene expression; and on laminar specimens from all groups for endothelial adhesion molecules, intercellular adhesion molecule (ICAM)-1, and E-selectin gene expression. Leukocyte emigration was assessed via CD13 immunohistochemistry, and gelatinase accumulation was determined by gelatin zymography. RESULTS: Laminar concentrations of IL-1beta, IL-6, IL-8, COX-2, ICAM-1, and E-selectin mRNA were significantly increased in ETP horses, compared with control horses. Concentrations of IL-1beta, IL-8, ICAM-1, and E-selectin mRNA peaked at 1.5 hours. In ETP horses, leukocyte emigration was present in 3 of 5 horses and pro-MMP-9 was detected in 2 of 5 horses. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that endothelial activation and laminar inflammation are early events in laminitis; MMP accumulation likely is a downstream event.     

Effects of enteral and intravenous fluid therapy, magnesium sulfate, and sodium sulfate on colonic contents and feces in horses

OBJECTIVE: To assess changes in systemic hydration, concentrations of electrolytes in plasma, hydration of colonic contents and feces, and gastrointestinal transit in horses treated with IV fluid therapy or enteral administration of magnesium sulfate (MgSO4), sodium sulfate (NaSO4), water, or a balanced electrolyte solution. ANIMALS: 7 horses with fistulas in the right dorsal colon (RDC). PROCEDURE: In a crossover design, horses alternately received 1 of 6 treatments: no treatment (control); IV fluid therapy with lactated Ringer's solution; or enteral administration of MgSO4, Na2SO4, water, or a balanced electrolyte solution via nasogastric intubation. Physical examinations were performed and samples of blood, RDC contents, and feces were collected every 6 hours during the 48 hour-observation period. Horses were muzzled for the initial 24 hours but had access to water ad libitum. Horses had access to hay, salt, and water ad libitum for the last 24 hours. RESULTS: Enteral administration of a balanced electrolyte solution and Na2SO4 were the best treatments for promoting hydration of RDC contents, followed by water. Sodium sulfate was the best treatment for promoting fecal hydration, followed by MgSO4 and the balanced electrolyte solution. Sodium sulfate caused hypocalcemia and hypernatremia, and water caused hyponatremia. CONCLUSIONS AND CLINICAL RELEVANCE: Enteral administration of a balanced electrolyte solution promoted hydration of RDC contents and may be useful in horses with large colon impactions. Enteral administration of either Na2SO4 or water may promote hydration of RDC contents but can cause severe electrolyte imbalances.     

Equine esophageal pressure profile

Esophageal motility was studied in 5 healthy adult horses, using a 4 side-hole catheter assembly continuously perfused with distilled water. Resting pressure and maximal pressures generated during swallowing were measured over the whole length of the esophagus (mean +/- S means = 132.7 +/- 2.31 cm). Four functionally distinct regions of the esophagus were demonstrated: cranial esophageal sphincter, caudal esophageal sphincter, and "fast" and "slow" regions in the body of the esophagus. The resting pressure of the cranial and caudal esophageal sphincters were 171.1 +/- 20.45 (x +/- S means) and 10.5 +/- 0.61 (x +/- S means) mm of Hg, respectively. The maximal pressure of the "fast" and the "slow" esophageal regions and caudal esophageal sphincter were 63.1 +/- 3.75 (x +/- S means), 71.9 +/- 3.65 (x +/- S means), and 63.1 +/- 2.60 (x +/- S means) mm of Hg, respectively. The length of each region and duration of pressure events were quantitated, establishing an equine esophageal pressure profile.