Risk factors associated with short-term outcome and development of perioperative complications in dogs undergoing surgery because of gastric dilatation-volvulus: 166 cases (1992-2003)

OBJECTIVE: To evaluate risk factors associated with death and development of perioperative complications in dogs undergoing surgery for treatment of gastric dilatation-volvulus (GDV). DESIGN: Retrospective case series. ANIMALS: 166 dogs. PROCEDURES: Records of dogs with confirmed GDV that underwent surgery were reviewed. Logistic regression was performed to identify factors associated with development of complications (ie, hypotension, arrhythmias, gastric necrosis necessitating gastrectomy, disseminated intravascular coagulation, peritonitis, sepsis, postoperative dilatation, postoperative vomiting, and incisional problems) and with short-term outcome (ie, died vs survived to the time of suture removal). RESULTS: Short-term mortality rate was 16.2% (27/166). Risk factors significantly associated with death prior to suture removal were clinical signs for > 6 hours prior to examination, combined splenectomy and partial gastrectomy, hypotension at any time during hospitalization, peritonitis, sepsis, and disseminated intravascular coagulation. Partial gastrectomy was not a significant risk factor for death but was for peritonitis, disseminated intravascular coagulation, sepsis, and arrhythmias. Age, gastrectomy, and disseminated intravascular coagulation were risk factors for development of hypotension. Use of a synthetic colloid or hypertonic saline solution was associated with a significantly decreased risk of hypotension. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the prognosis for dogs undergoing surgery because of GDV is good but that certain factors are associated with an increased risk that dogs will develop perioperative complications or die.     

犬胃扩张-肠扭转的风险因子和预防

胃扩张-肠扭转(Gastric Dilatation-Volvulus--GDV)又称为"臌"、"胃扭转"。GDV是一个极其严重,并应视为严重威胁犬生命的紧急事件,是仅次于癌症导致犬死亡的第二大杀手。24%的犬臌是由胃膨胀引起的。但是大多数的情况(75%)是由于胃扭转,弯曲和切断胃内容物的流入和流出。由于胃部膨胀,可旋转90°至360°,固定附着在食道和十二指肠之间缠绕。膨胀的胃妨碍腹部静脉、减少血液返回到心脏,丧失血液供应,导致低血压、胃缺血、休克、脏器损害,要在育种,饲养和管理上加强监管,有效的降低形成和促发GDV风险因子的条件,加强对GDV风险因子的预警和识别,以及发生后的及时发现和立即处理治疗。     

Performing both lateral abdominal radiographs may not improve the visualization of gas in the gastric outflow tract of cats

Reports in the veterinary literature support three‐view abdominal radiographs as a standard of practice for evaluating dogs with suspected gastrointestinal (GI) diseases. The usefulness of three‐view abdominal studies has not been evaluated in cats. Images from a prospective crossover group study with 20 healthy cats, and those from a retrospective cohort study of 110 cats, were reviewed and the location and degree of gas was assessed in the gastric outflow tract. Comparisons of the frequency of luminal gas were made between the views and between cats with GI disease versus cats without and between cats having sedation versus those without. Chi‐Square analysis was performed with P < .05 being considered significant. No significant difference was found in the location and degree of luminal gas in left versus right lateral views in all cats regardless of the order in which the views were obtained or in cats with GI disease versus cats without. Cats with gastric dilation had a higher overall frequency of gas; those with dilation with homogeneous material were higher than those with dilation with heterogeneous material. A higher frequency of gas was found in sedated cats than nonsedated, but further study is needed to determine the underlying cause. Based on these findings, a three‐view abdominal study for cats as a standard of practice may not be necessary, but obtaining the additional lateral view when gastric dilation is present might allow better visualization of the pyloric antrum and duodenum.     

Cardiopulmonary measurements in dogs undergoing gastropexy without gastrectomy for correction of gastric dilatation-volvulus.

OBJECTIVE: To measure cardiopulmonary variables, including cardiac index, in dogs with naturally acquired gastric dilatation-volvulus (GDV). DESIGN: Prospective clinical study. ANIMALS: 6 dogs with GDV. PROCEDURE: In addition to typical medical and surgical management of GDV, the dorsal metatarsal and pulmonary arteries and right atrium of the dogs were catheterized to obtain cardiopulmonary measurements before and during anesthesia and surgery. RESULTS: All dogs underwent gastropexy but none required gastrectomy. Mean cardiac index and mean arterial blood pressure for this small population of dogs with GDV were not significantly different from those reported for clinically normal awake or anesthetized dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs with naturally acquired GDV without gastric necrosis may not have the classic characteristics, including decreased cardiac index and hypotension, of hypovolemic circulatory shock.     

Acute necrotising pancreatitis following grain overload in a donkey

A donkey developed abdominal discomfort and distension together with cardiovascular collapse and gastric reflux 24 to 36 hours after ingesting a large amount of poultry feed. Rectal findings prompted a laparotomy that identified extensive gastric dilation, an empty, atonic small intestine, dry colonic content and an easily corrected caecal displacement. These findings were not consistent with the severity of the signs, which were attributed to endotoxaemia. The donkey was euthanased during recovery. Necropsy revealed acute necrotising pancreatitis with massive gastric dilation and right dorsal colon impaction. The clinicopathological features of acute equine pancreatitis associated with grain overload are discussed.     

Non-cholinergic mechanisms underlying the acute lethal effects of P = S type organophosphorus insecticides in rats.

Intravenous administration of the lethal dose of diazinon or fenthion, P = S type organophosphates, to urethan anesthetized rats induced bradycardia and transient apnea followed by a decline of blood pressure, and death. We investigated the mechanisms of the lethal action of these organophosphates in rats through measurements of blood pressure, heart rate, and respiratory pattern. We compared their cardiorespiratory effects in the five different conditions under anesthesia; 1) normal (without treatment), 2) artificially ventilated, 3) vagotomized, 4) atropinized, 5) pithed, vagotomized and atropinized. It was found that the administration of 200 mg/kg of fenthion and 100 mg/kg of diazinon, caused sudden bradycardia, transient apnea and gradual decline of blood pressure in the anesthetized normal rat, and the rat died. The rats in other conditions also died except the artificially ventilated rats, in which 400 mg/kg of fenthion was administered to cause hypotension and subsequent death. Hypotension was observed consistently even after the cardiac effect such as bradycardia was eliminated by atropine treatment. In the pithed rats which were further vagotomized and atropinized, these organophosphates also caused hypotension. These results may indicate that hypotension is the main cause of death which resulted from intravenous administration of the P = S types. Hypotension may be caused by peripheral cardiovascular effect of the P = S types, which is unrelated to cholinergic mechanisms.     

Effect of staphylococcal enterotoxin B on cardiorenal functions in rhesus macaques.

Selected cardiovascular and renal functions were measured for 5 hours in conscious, chair-restrained, female rhesus macaques (Macaca mulatta) after IV (0.05 and 1.0 mg/kg) or oral (1.0 mg/kg) administration of staphylococcal enterotoxin B (SEB). Cardiovascular functions, renal hemodynamics, and renal metabolism were also studied between 6 and 11 hours after IV SEB inoculation. Oral SEB produced few changes in cardiorenal functions. In contrast, IV SEB produced hypotension, tachycardia, increased total peripheral and renal vascular resistance, and decreased cardiac and renal functions. The early significant (P less than 0.05) renal depression was not associated with hypotension (mean arterial blood pressure greater than 100 mm of Hg). However, all measured renal functions except extraction ratio of PAH were positively correlated with decreased blood pressure (r = 0.52 - 0.71) in the later phase of SEB toxemia. It is concluded that the kidney is one of the organs affected by IV SEB. Renal impairment may partially contribute to death during SEB enterotoxemia in macaques.     

Plastinated heart slices aid echocardiographic interpretation in the dog

Our aim was to compare plastinated sections of the canine heart with corresponding two-dimensional (2D) echocardiographic images. Thirteen dog hearts were fixed by dilation and then processed by the S10 silicon plastination method (Biodur). Two dogs without evidence of cardiac disease were imaged using 2D echocardiography so as to obtain a complete series of the standard right and left parasternal images, which were compared with corresponding plastinated slices obtained by knife sectioning of the hearts. The plastinated slices revealed the internal anatomy of the heart with great detail and were particularly useful to display the spatial relationship between complex anatomic structures. The plastinated slices corresponded accurately with the echocardiographic images. Because of the dilation of the right heart during the fixation process, it was not possible to obtain plastinated specimens in ventricular systole. This paper may be a reference atlas for assisting 2D echocardiography interpretation.     

Gastric rupture in horses: a review of 54 cases

The historical, clinical, laboratory, surgical and necropsy findings in 54 cases of gastric rupture in horses are described. Eleven per cent of the deaths of horses undergoing exploratory coeliotomy for colic during the period of the study were a result of gastric rupture. Comparison with all horses which had exploratory coeliotomies for colic over an eight year period did not show that horses with gastric rupture were different from these reference horses regarding age, breed or season. There were fewer stallions than expected in the gastric rupture group. Horses with histories of both acute and chronic (more than 36 h) colic were susceptible to gastric rupture. Primary and idiopathic causes of gastric dilation and rupture accounted for about one-third of the horses. All but one of these cases resulting from secondary causes fell into three aetiologically-related groups: obstructive, peritoneal and enteric, with approximately equal numbers of horses in each group. Most of the ruptures occurred along the greater curvature of the stomach. At least six horses ruptured their stomachs postoperatively in the presence of an indwelling nasogastric tube. The presence or absence of gastric reflux following nasogastric intubation was not a reliable indicator, on its own, of gastric dilation. Horses that later died from gastric rupture had markedly elevated heart rate, hypochloraemia, peritoneal exudative effusion (particularly with evidence of sepsis), pre- and/or postoperative gastric reflux and small or large intestinal disease. However, no distinctive feature of these horses was shown to place them at risk of gastric rupture.     

Anesthesia for cesarean section in the dog.

At the time of cesarean section, the mother may suffer respiratory depression, hypotension, increased gastric acidity, and increased predisposition to regurgitation, and the newborn may suffer anesthetic-induced respiratory depression. Preanesthetic metaclopramide, cimetidine, and anticholinergic agent are recommended. Sedatives can be administered if necessary. Neuroleptanalgesic and low-dose general anesthetic, with local anesthetic line-blocks, are preferred techniques. Supportive care of the newborn is mandatory.     

Studies of oesophageal function

Lesions of the sympathetic nervous system have been associated with grass sickness for many years (Obel, 1955). Dysphagia is also an accepted clinical feature of subacute or chronic cases. Megaoesophagus has been reported in horses with grass sickness, but it was uncertain whether oesophageal dilation was a primary condition, or a sequel to gastric distension (Greet, 1982). Robertson and others, (1948) suggested that dysphagia was alleviated in affected horses after drainage of gastric contents. It is interesting to note that dysphagia was present in less than half the cases in this study although radiological abnormalities of the oesophagus were similar in all cases. Consistent radiological abnormalities of the oesophagus occurred in 12 out of the 14 horses examined (this consisted of incoordination or atony of the thoracic oesophagus). In the two suspected cases of grass sickness which made a clinical recovery, the radiological abnormalities were slightly different. Contrast material was transferred slowly through the cervical oesophagus and pooled at the thoracic inlet as well as at several sites in the cervical oesophagus. Eventually the contrast material passed through the distal oesophagus into the stomach. Although gastric distension was present in many of the cases examined it was not possible to identify this by radiographic means. It is unlikely that the signs of oesophageal incoordination and dilation were related only to gastric distension, as in most of the cases, contrast material pooled in the oesophagus at the thoracic inlet rather than just cranial to the diaphragm. It seems reasonable to suggest that these radiological abnormalities resulted from neurological impairment of the oesophagus. It would be of particular value to examine horses with obstructive lesions of the stomach or duodenum to evaluate the effect of upper gastro-intestinal obstruction on oesophageal motility. A number of horses with other conditions of the upper alimentary tract have been examined radiographically at these clinics. Two horses suspected of suffering from grass sickness were found to have primary oesophageal abnormalities. One had a diverticulum and the other a localized area of dilation; both showed regurgitation of food and weight loss. Barium swallows in both horses defined the sites of their localized lesions but there was no evidence of either Type I or Type II oesophageal malfunction, and at post-mortem examination the ganglionic changes associated with grass sickness were absent. Examination of one horse with ileocaecal intussusception did not show radiological features of the oesophagus typical of those shown by cases of grass sickness. However, contrast material passed slowly through the upper oesophagus of a foal with congenital megaoesophagus in a manner similar to the Type II oesophageal malfunction described above. It also demonstrated dilation and gross inco-ordination of the thoracic oesophagus with pooling of contrast material at the thoracic inlet and oscillation between the thoracic inlet and diaphragm as seen in Type I malfunction in proven grass sickness. It is recognized that the radiological findings of oesophageal dilation and inco-ordination merely demonstrate the presence of neuromuscular impairment of oesophageal movement. Until more cases of upper gastro-intestinal disease can be examined, the specificity of these functional abnormalities for grass sickness cannot be accurately assessed. However the results assume considerable diagnostic significance when demonstrated in an adult horse which is exhibiting signs of grass sickness, particularly those of colonic impaction. The need for sophisticated equipment and thus the necessity of transport to centres so equipped, is clearly a drawback to the technique but this is often outweighed by the advantage of being able to avoid unnecessary laparotomy. As there is at present no cure for grass sickness, the improved diagnostic capability will allow severely ill horses to be destroyed without delay. It may also identify horses which on rare occasions appear to be making a slow recovery.     

Esophagitis and esophageal strictures.

Esophagitis and esophageal strictures are important causes of esophageal disease in dogs and cats. Clinical suspicion is created when the clinician recognizes the clinical signs suggestive of esophageal disease and accounts for historical information and physical examination findings. Once suspected, the diagnosis of esophagitis and esophageal strictures is a fairly simple one in most cases. Although the benefit of diminishing secretion of gastric acid in patients with esophagitis is unquestioned, other questions regarding adjunctive medical treatments, such as sucralfate and glucocorticoids for dogs and cats with esophagitis, have not been answered through appropriate clinical studies. Esophageal strictures are readily treated with balloon dilation or esophageal bougienage, and clients can expect most patients to become functional, although dietary change may be necessary.     

Acid-base-balance status and blood gas analysis in rabbits with gastric stasis and gastric dilation

Background: The aim of this study was to analyse the acid-base-balance status and blood gas values in rabbits with gastric stasis and gastric dilation syndrome. Methods: Thirty rabbits with corresponding symptoms and radiographs were sampled before, during, and after treatment and an arterial acid-base-balance status and blood gas analysis was performed. Results: pCO₂, HCO₃, and base excess were significantly lower in animals that were presented 12 hours after the owner had registered signs of illness than animals presented within 6 hours. Of the examined rabbits, 57% had acidosis, 83% of which were of metabolic origin. The pH returned to normal after treatment in 94% of surviving animals (24/30). Conclusions: Gastric stasis and dilation syndrome has a considerable impact on the acid-base-balance status and blood gas analysis in rabbits and its measurement is therefore valuable for assessing the patient's status and adjusting the therapy accordingly to each animal's needs. Clinical relevance: Our findings underline the importance of a swift introduction of rabbits with gastric stasis and dilation syndrome into veterinary care to prevent further impairment of secondary findings such as metabolic acidosis.     

Effects of plasma expansion on the pituitary-adrenocortical response to halothane anaesthesia in sheep

The study aimed to investigate the stimulus to adrenocortical activity that is induced by halothane anaesthesia. Groups of 7 sheep were anaesthetised with thiopentone and halothane (TH) or acepromazine, thiopentone and halothane (ATH). During 120 min of anaesthesia hypotension was prevented (mean arterial blood pressure kept at pre-anaesthetic level) by infusion of a modified gelatine plasma replacer given to effect (0.34–1.1 litres with TH and 1.1–3.1 litres with ATH). Pulse rate, arterial blood pressure and gases were measured and sequential samples withdrawn for analysis of plasma cortisol, adrenocorticotrophic hormone (ACTH), arginine vasopressin (AVP), glucose and lactate. Heart rate increased in the ATH but not the TH group. All sheep were well oxygenated but developed hypercapnia and respiratory acidosis. In both groups, cortisol increased more than 2-fold 20 min after the end of anaesthesia but there were no significant changes in ACTH. AVP was measured in the TH group only and increased 3-fold at the end of anaesthesia. Glucose and lactate remained stable except for lactate in the TH group which decreased during anaesthesia. These data indicate that hypotension is a major component of the stimulus inducing adrenocortical activity during halothane anaesthesia. However, maintenance of normotension did not entirely depress the response; halothane itself or decreased perfusion may also contribute.     

A retrospective and prospective study of megaesophagus in the parma wallaby (Macropus parma) at the San Diego Zoo, California, USA

At the San Diego Zoo (California, USA), 22 cases of megaesophagus were diagnosed in the parma wallaby (Macropus parma); a prevalence of 21.1%. Parma wallabies often have no clinical signs until severe and chronic dilation of the esophagus is present. Clinical signs of advanced disease include weight loss, swelling of the cervical region, regurgitation without reswallowing of ingesta, short flight distance, depression, collapse, dyspnea, and sudden death. Retrospective and prospective studies at the San Diego Zoo and a multi-institutional survey in the United States were used to try to determine the cause of megaesophagus. The retrospective study did not identify an etiology. The prospective study revealed megaesophagus and severely delayed esophageal transit time in eight of eight animals. Myasthenia gravis, lead toxicosis, toxoplasmosis, and thyroid disease were eliminated as possible causes. Of 286 living and dead parma wallabies surveyed at other institutions, three cases of esophageal diverticulum and one case of megaesophagus were reported. The cause of megaesophagus in parma wallabies was not determined.     

Aspiration of barium-impregnated polyethylene spheres by a dog

This case report describes an 11-year-old Belgian Malinois dog with acute onset of cough caused by aspiration of barium-impregnated polyethylene spheres (BIPS) and pneumonia following an episode of suspected gastric dilation. Although bronchoscopic retrieval of the BIPS was largely unsuccessful, the dog recovered uneventfully, with most of the BIPS being coughed out and swallowed over a 1-month period. Aspiration of BIPS should be considered a potential complication of their administration. Furthermore, endoscopic removal of aspirated BIPS is challenging and may not be indicated because of their inert nature and possible self-clearance.     

A retrospective and prospective study of megaesophagus in the parma wallaby (Macropus parma) at the San Diego Zoo, California, USA

At the San Diego Zoo (California, USA), 22 cases of megaesophagus were diagnosed in the parma wallaby (Macropus parma), yielding a prevalence of 21.1%. Parma wallabies often have no clinical signs until severe and chronic dilation of the esophagus is present. Clinical signs of advanced disease include weight loss, swelling of the cervical region, regurgitation without reswallowing of ingesta, short flight distance, depression, collapse, dyspnea, and sudden death. Retrospective and prospective studies at the San Diego Zoo and a multi-institutional survey in the United States were used to try to determine the cause of megaesophagus. The retrospective study did not identify an etiology. The prospective study revealed megaesophagus and severely delayed esophageal transit time in eight of eight animals. Myasthenia gravis, lead toxicosis, toxoplasmosis, and thyroid disease were eliminated as possible causes. Of 286 living and dead parma wallabies surveyed at other institutions, three cases of esophageal diverticulum and one case of megaesophagus were reported. The cause of megaesophagus in parma wallabies was not determined.     

Toxicology of oil field wastes. Hazards to livestock associated with the petroleum industry

In oil-producing states, the proximity of livestock to drilling operations and production sites often results in poisoning of animals from ingestion of crude oil, condensate, salt water, heavy metals, and caustic chemicals. The heavy metals encountered most frequently are lead from pipe joint compound and arsenicals and chromates used as corrosion inhibitors. Numerous toxic and caustic chemicals are used in drilling muds and fluids. Crude oil and salt water spills are common occurrences around production sites. Pipeline breaks may result in exposure of livestock to crude oil or refined petroleum hydrocarbons. Ingestion of petroleum hydrocarbons may result in sudden death from peracute bloat. The most common cause of illness or death following exposure to petroleum hydrocarbons is aspiration pneumonia, which may cause a chronic progressive deterioration of health, with death after several days or weeks. Cases in which livestock are exposed to oil, salt water, or caustic chemicals, but do not die acutely or from aspiration pneumonia are more frustrating to diagnose. In these cases, parasitism, poor nutrition, and other debilitating diseases must be considered. Anorexia, weight loss, and decreased rumen motility may be caused by a disruption of normal rumen function. Petroleum hydrocarbons, salt water, and caustic chemicals have the potential of altering rumen flora and enzymatic processes as well as damaging the ruminal and gastrointestinal epithelium. The toxicity of petroleum hydrocarbons appears to be related more closely to the volatility and viscosity of the product than to other factors. The more volatile straight chain and aromatic petroleum hydrocarbons have a greater potential for aspiration pneumonia and may produce an anesthetic-like action if absorbed systemically. The more volatile petroleum hydrocarbons also are more irritating to skin and mucous membranes and appear to be more damaging to rumen flora. Treatment of petroleum hydrocarbon ingestion is aimed at preventing aspiration pneumonia and the animal's absorption of highly volatile components. Activated charcoal slurries and, in some instances, vegetable oil may be used to absorb the ingested petroleum or alter its viscosity to minimize absorption and aspiration. These procedures should be followed by the administration of rumenatories or saline cathartics to hasten the evacuation of the gastrointestinal tract. Chronic poor performance animals with anorexia and rumen dysfunction may respond to fresh rumen inoculant, intravenous glucose, and B-complex vitamins. Prognosis primarily hinges on whether or not aspiration pneumonia has occurred. Treatment of aspiration pneumonia rarely is effe     

Follow-up studies by peroral gastric biopsies and necropsy in vomiting dogs.

The results of follow-up studies in 139 vomiting dogs are presented. Follow-up studies were performed by biopsies in 34 dogs, by biopsies and necropsy in six dogs and by necropsy only in 99 dogs. The times between the first and the last series of biopsies varied from three to 1042 days and from one to 656 days between the first series of biopsies and necropsy. From the 55 dogs with gastritis in the first series of biopsies, 35 also showed gastritis in the following biopsies or at necropsy. These were mainly severe types of gastritis such as diffuse, hypertrophic or atrophic. Ten dogs with superficial gastritis showed no gastric changes at necropsy, two dogs had edema only and three dogs had gastric changes other than gastritis, such as multiple polyps. In general, carcinoma and lymphosarcoma were found in the biopsies as well as at necropsy, but in three cases of terminal carcinoma only gastritis had been diagnosed initially. In 35 dogs the first series of gastric biopsies showed no pathological changes, but in 22 of these dogs gastritis, ulceration, fibrosis, atrophy, gastric dilation with local necrosis, and perforation or lymphosarcoma of the submucosa were found in the second series of biopsies or at necropsy. Several dogs which did not have gastric changes at necropsy had enteritis or intestinal lymphosarcoma.