Effect of acute gastric dilatation on gastric myoelectic and motor activity in dogs.

OBJECTIVE: To investigate the effects of experimentally induced acute gastric dilatation on electrical and mechanical activities of the stomach in dogs. ANIMALS: 7 healthy dogs. PROCEDURE: Electrodes and strain-gauge force transducers were implanted on the serosal surface of the antrum and pylorus. Eight days later, baseline gastric electrical and contractile activities were recorded. The dogs were anesthetized and mechanically ventilated to maintain normocapnia while the stomach was distended (intragastric pressure, 30 mm Hg) for 180 minutes, using a thin compliant bag. Gastric electrical and contractile activities were recorded again on days 1 and 10 after dilatation. Recordings were analyzed to determine gastric slow-wave frequency, slow-wave dysrhythmia, propagation velocity of slow-waves, coupling of contractions to slow waves, motility index on the basis of relative contractile amplitudes, and onset of contractions after a standardized meal. RESULTS: Electrical or contractile activities were not significantly different 18 hours after acute gastric dilatation (day 1). Arrhythmias were evident before and after gastric dilatation in dogs from which food was withheld and in dogs after consumption of a meal. CONCLUSIONS: Variables for assessing gastric electrical and contractile activities were unaffected 18 hours after acute gastric dilatation. CLINICAL RELEVANCE: Analysis of results of this study indicated that altered electrical and contractile activities in dogs with short-term gastric dilatation are not likely to be secondary to the process of acute gastric dilatation.     

Gastric Myoelectric and Motor Activity in Dogs After Isoflurane Anesthesia

To characterize the effects of isoflurane on gastric motility, gastric electrical and contractile activities were assessed in six healthy adult dogs before and after recovery from anesthesia. Baseline recordings (fasting and fed state) were obtained in unanesthetized dogs 8 days after implantation of serosal electrodes and strain-gauge force transducers. After an overnight fast, dogs were anesthetized with 1.3 minimum alveolar concentration (MAC) isoflurane for 4.5 hours (approximately 6 MAC hours). No other anesthetic or sedative drugs were administered. During anesthesia, ventilation was mechanically controlled to maintain arterial carbon dioxide tension at 36 ± 4 mm Hg. Gastric electrical and contractile activities (fasting and fed state) were recorded again 18 hours after recovery from isoflurane anesthesia. Recordings were analyzed to determine gastric slow-wave frequency, presence of slow-wave dysrhythmias, slow-wave propagation velocity, coupling of contractions to slow waves, a motility index based on relative contractile amplitudes, and onset and duration of contractions after a standardized meal. The only variable that was significantly decreased 18 hours after 6 MAC hours of isoflurane anesthesia was the gastric motility index during fasting-state phase III. This decrease was not apparent in the fed-state test periods. Our results suggest that, with the exception of gastric motility index during fasting-state phase III, variables for gastric electrical and contractile activities in dogs are unaffected by isoflurane 18 hours after anesthesia.     

Ultrasonographic evaluation of adhesions induced by incisional gastropexy in 16 dogs

A study was undertaken to evaluate the use of ultrasonography to assess the gastropexy site for permanent adhesion in clinical cases. Two groups, each comprising eight dogs, were studied, all 16 cases undergoing decompression, anatomical repositioning of the stomach and an incisional gastropexy after gastric dilatation-volvulus (GDV). Group 1 was set up as a prospective group in which ultrasonographic examinations were performed three times (mean three, 12 and 67 days) after surgery to evaluate the gastropexy region. The gastropexy site was assessed ultrasonographically at only one stage (mean 449 days after surgery) in the group 2 dogs. Criteria used to assess the usefulness of the ultrasonographic evaluation included the ability to identify the gastropexy site, to obtain measurements of the length and thickness of the site and to assess the ultrasonographic appearance of the different gastric wall layers. The average number of peristaltic contractions and degree of gastric filling were also evaluated. The fixation between the stomach and the abdominal wall was easily detected in all 16 cases. Ultrasonography proved to be a simple and non-invasive technique to assess the permanency of the gastropexy. The Incisional gastropexy was relatively easy to perform and induced permanent adhesions in all 16 dogs, without recurrence of GDV.     

A Laparoscopic‐Sutured Gastropexy Technique In Dogs: Mechanical and Functional Evaluation

Objective— To describe a laparoscopic‐sutured gastropexy technique in dogs and evaluate the tensile strength of the adhesion and effects on gastric function. Study Design— Experimental study. Animals— Female beagle dogs (n=7). Methods— A laparoscopic‐sutured gastropexy technique was evaluated by ex vivo tensile distraction tests 10 weeks after surgery. The effect of the adhesion on gastric emptying, mucosal permeability, and systemic inflammation were evaluated by monitoring the C‐reactive protein (CRP) and sucrose permeability, and by radiographic evaluation of gastric emptying 2 weeks before and 10 weeks after surgery. Results— Mean (±SD) tensile force to disrupt adhesions was 51.1±16.4 N. There was no significant postoperative increase in CRP concentration or change in sucrose permeability. The area under the curve representing the postprandial decrease in gastric radiographic area increased by 11% after gastropexy. Conclusions— This laparoscopic gastropexy technique had appropriate mechanical and functional characteristics with limited morbidity. Clinical Relevance— This laparoscopic‐sutured gastropexy provides adhesion strength comparable with other gastropexy techniques tested at 10 weeks postoperatively. Only minor changes in gastric emptying were observed 10 weeks after surgery.     

Recurrence of gastric dilatation-volvulus after incisional gastropexy in a rottweiler

An adult, castrated male rottweiler with a history of gastric dilatation-volvulus (GDV), which was treated 4 months previously by surgical gastric resection and incisional gastropexy, had a recurrence of clinical signs. Abdominal exploratory surgery revealed a 180 degrees -clockwise GDV, with a stretched adhesion at the original gastropexy site. The stomach was repositioned, and additional gastropexies were performed adjacent to the original gastropexy site and at the gastric fundus. The recurrence of GDV in this dog with an intact gastropexy suggested that a risk for volvulus remains after therapeutic incisional gastropexy.     

Circumcostal gastropexy for preventing recurrence of gastric dilatation-volvulus in the dog: an evaluation of 30 cases

Follow-up evaluation (mean, 13.7 months) was obtained in 30 dogs with gastric dilatation-volvulus that were surgically treated with circumcostal gastropexy. Evaluation was performed by questionnaire (29 dogs), radiographic contrast studies (23 dogs), and necropsy (6 dogs). The gastropexy was thought to be intact in all 23 dogs examined radiographically. Necropsy of 6 dogs dying from causes unrelated to gastric dilatation-volvulus (mean of 12.7 months after surgery) revealed an intact gastropexy site in each dog. Only 1 (3.3%) dog had clinical recurrence of gastric dilatation after surgery. Five additional dogs dying postoperatively were necropsied and had intact gastropexy sites.     

Prospective evaluation of laparoscopic-assisted gastropexy in dogs susceptible to gastric dilatation

OBJECTIVE: To determine long-term outcome associated with laparoscopic-assisted gastropexy in prevention of gastric dilatation-volvulus (GDV) in susceptible dogs and to evaluate use of laparoscopy to correct GDV. DESIGN: Prospective study. ANIMALS: 25 client-owned large-breed dogs. PROCEDURE: 23 dogs susceptible to GDV were referred as candidates for elective gastropexy. These dogs had a history of treatment for gastric dilatation, clinical signs of gastric dilatation, or family members with gastric dilatation. Laparoscopic-assisted gastropexy was performed. One year after surgery, abdominal ultrasonography was performed to evaluate the attachment of the stomach to the abdominal wall. Two dogs with GDV were also treated with laparoscopic-assisted derotation of the stomach and gastropexy. RESULTS: None of the dogs developed GDV during the year after gastropexy, and all 20 dogs examined ultrasonographically had an intact attachment. Another dog was euthanatized at 11.5 months for unrelated problems. Two dogs with GDV successfully underwent laparoscopic-assisted gastropexy after the stomach was repositioned. CONCLUSIONS AND CLINICAL RELEVANCE: Laparoscopic-assisted gastropexy resulted in a persisting attachment between the stomach and abdominal wall, an absence of GDV development, and few complications. Dogs with a high probability for development of GDV should be considered candidates for minimally invasive gastropexy. Carefully selected dogs with GDV can be treated laparoscopically.     

Gastric emptying of nondigestible radiopaque markers after circumcostal gastropexy in clinically normal dogs and dogs with gastric dilatation-volvulus.

Using radiopaque particles mixed with food, gastric emptying was assessed in healthy dogs not subjected to surgery, in healthy dogs 9 to 35 days after circumcostal gastropexy, and, in dogs 1 to 54 months after surgical treatment and recovery from gastric dilatation-volvulus (GDV). Circumcostal gastropexy surgery did not alter the 90% gastric emptying time for radiopaque particles in healthy dogs. However, 90% gastric emptying time was significantly (P less than 0.05) increased after circumcostal gastropexy in dogs with GDV, compared with healthy dogs after the same surgical procedure and recovery period. These results imply that dogs with GDV have delayed gastric emptying of solid particles. Whether delayed gastric emptying of markers detected in affected dogs after surgical treatment and recovery was the result or the cause of GDV was not determined. Results indicate that circumcostal gastropexy could be recommended as a prophylactic procedure for GDV in large breeds with deep thorax, because delayed gastric emptying of markers secondary to the surgical procedure is unlikely.     

Purinergic control of the quail rectum: modulation of adenosine 5'-triphosphate-mediated contraction with acetylcholine

Electrical field stimulation (EFS) induces frequency-dependent contractions of the longitudinal muscle of isolated quail rectum which were sensitive to tetrodotoxin. The aim of the present study was to investigate whether purinergic neurons are implicated in the response to nerve stimulation. The shape of the EFS-induced contractile response was different depending on stimulus frequency; low frequencies (0.5-2 Hz) induced fast monophasic contractions with a small subsequent relaxation; whereas higher frequencies (5-50 Hz) induced biphasic contractile response that comprised fast initial component (as in case of low frequency) and a slow delayed contractile component in addition to the relaxation that follows the fast contractile component. Prior application of atropine (10 microM) completely abolished the slow delayed component but significantly enhanced the fast initial contractile component. Physostigmine (1-10 microM) significantly enhanced the slow delayed component with an inhibitory effect on the initial fast component. The nonspecific purinergic receptor antagonist, suramin (100-500 microM) significantly inhibited the fast initial contractile component with no significant effect on the slow delayed one. Complete blockade of the fast component was achieved by prior application of a combination consisted of suramin (50 microM) and pyridoxicalphosphate-6-azophenyl 2',4'-disulphonic acid tetrasodium (PPADS; 10 microM). Exogenous applications of adenosine 5'-triphosphate and acetylcholine (10 microM each), produced contractile responses that mimicked those induced by EFS. These data suggest that ATP is the main noncholinergic excitatory transmitter controlling the contractile activity of the quail rectum; and that its action could be modulated by acetylcholine.     

Combined laparoscopic ovariectomy and laparoscopic-assisted gastropexy in dogs susceptible to gastric dilatation-volvulus

This prospective study describes a simple method of combining laparoscopic ovariectomy and laparoscopic-assisted prophylactic gastropexy and determines the duration of surgery, complications, and long-term outcome including prevention of gastric dilatation-volvulus (GDV). Laparoscopic ovariectomy and laparoscopic-assisted gastropexy were performed on 26 sexually intact female dogs susceptible to GDV. The mean surgery time was 60.8 ± 12.4 min. No GDV episode was seen during the study period (mean follow-up: 5.2 ± 1.4 y). All dogs had an intact gastropexy attachment assessed by ultrasonography at 1 y. Post-operative complications were minor and owners were satisfied with the procedure. Combined laparoscopic ovariectomy and laparoscopic- assisted gastropexy appears to be a successful and low morbidity alternative procedure to both ovariectomy/ovariohysterectomy and gastropexy via open ventral-midline laparotomy.     

Recurring gastric volvulus in a dog

A successful prophylactic permanent gastropexy was performed on a dog that had previously experienced four gastric volvulus procedures, one prophylactic pyloroplasty, and two subsequent gastric volvulus repairs. Radiographic evaluation of the previous pyloroplasty and the final permanent gastropexy are illustrated.     

Belt loop gastropexy in the management of gastroesophageal intussusception in a pup.

Gastroesophageal intussusception and megaesophagus were diagnosed in a 5-week-old German Shepherd Dog. Exploratory surgery was performed, and belt loop gastropexy was used to maintain proper gastric position after manual reduction of the intussusception. The pup survived surgery and was clinically normal when it was 6 months old. Follow-up contrast radiography revealed resolution of the megaesophagus and apparent permanent gastropexy. Previous reports have indicated extremely high mortality for gastroesophageal intussusception, and resolution of megaesophagus in the dog is unusual.     

Gastropexy with an automatic stapling instrument for the treatment of gastric dilatation and volvulus in 20 dogs

Surgical stapling equipment was used to create a gastropexy in 20 dogs undergoing emergency surgery for gastric dilatation and volvulus (GDV). The technique involved creation of a tunnel between the seromuscular layer and the submucosa of the pyloric antrum, and a matching tunnel beneath the right m. transversus abdominis. The arms of a gastrointestinal anastomosis stapling device were introduced into the tunnels, and the device was fired to create the gastropexy. One dog died of systemic sequelae of GDV during the early postoperative period. None of the remaining 19 dogs developed a recurrence of GDV during follow-up periods ranging from 5 to 43 months. In 11 dogs, the integrity of the gastropexy was evaluated by abdominal ultrasonography and either negative contrast gastrography or double contrast gastrography; in these dogs, the radiographic and/or the ultrasonographic findings were suggestive of an intact gastropexy. There were no complications involving the gastropexy staple line. The results of this study indicate that an effective and consistent permanent gastropexy can be created, using surgical stapling equipment.     

Evaluation of an endoscopically assisted gastropexy technique in dogs

OBJECTIVE: To evaluate the use of endoscopy in conjunction with a gastropexy technique in dogs as a potential means to aid prevention of gastric dilatation-volvulus. ANIMALS: 12 healthy adult medium- and large-breed dogs. PROCEDURES: 12 adult research dogs that had no abnormal physical examination findings each underwent an endoscopically assisted gastropexy procedure. On completion of the procedure, the dogs were euthanized and exploratory laparotomies were performed to evaluate the surgical site. Data recorded included anatomic location of the gastropexy, gastropexy length, and duration of procedure as well as any complications. RESULTS: Mean+/-SD gastropexy length was 3.3+/-0.25 cm, and mean duration of surgery was 18+/-7 minutes. In each dog, the stomach was located in its normal anatomic position and all gastropexies were sutured to the abdominal wall at the level of the pyloric antrum. The only complications during the procedure were needle bending and breakage at the time of stay suture placement. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of these findings, it appears that endoscopically assisted gastropexy is a simple, fast, safe, and reliable method of performing a prophylactic gastropexy in dogs when undertaken by a person who is skilled in endoscopy. Such a procedure maximizes the benefits of decreased morbidity and shorter duration of anesthesia associated with minimally invasive surgery. Further clinical studies are warranted to evaluate the long-term efficacy of this procedure in dogs at risk for development of gastric dilatation-volvulus.     

Ultrasonographic comparison of adhesions induced by two different methods of gastropexy in the dog

Ultrasonography was used to compare adhesions induced by two different methods of gastropexy in 16 dogs. An incisional gastropexy technique was used in eight dogs (group 1) and a 'modified' gastropexy technique in the remaining eight (group 2). The length and thickness of the gastropexy and the peristaltic activity of the stomach were measured ultrasonographically and compared between groups. Measurements for the two groups were taken in the early postoperative interval (two to four days), intermediate postoperative interval (eight to 20 days) and late postoperative interval (57 to 79 days). Both techniques were equally successful in forming permanent adhesions at two months postoperatively and there was no recurrence of gastric dilatation and volvulus. The length and thickness of the gastropexy were similar for both groups at two months postoperatively and there were no surgical complications with either technique. The modified gastropexy provides a technique that can easily be performed by a single surgeon , with no increased operative time or duration of anaesthesia, and with the formation of a permanent adhesion.     

Barrier pressure at the gastroesophageal junction in anesthetized dogs.

OBJECTIVE: To evaluate the effect of body position on barrier pressure at the gastroesophageal junction in anesthetized Greyhounds and to assess alterations in barrier pressure following gastropexy. ANIMALS: 8 adult Greyhounds. PROCEDURE: Barrier pressure at the gastroesophageal junction was measured by fast (1 cm/s) and slow (1 cm/10 s) withdrawal of a subminiature strain gauge transducer through the gastroesophageal junction in 8 anesthetized dogs. The effect of body position was measured. Each dog then was placed in right-lateral recumbency, and gastropexy was performed in the left flank. Additional measurements were obtained 1, 5, 10, 20, and 30 minutes after gastropexy. RESULTS: Barrier pressure for dogs positioned in sternal recumbency (mean +/- SEM, 1.1 +/- 0.53 mm Hg) was significantly less than for dogs positioned in right lateral or left lateral recumbency. Following gastropexy, there was a steady increase in barrier pressure. Thirty minutes after gastropexy, barrier pressure was significantly higher (13.36 +/- 3.46 mm Hg), compared with the value before surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Barrier pressure in anesthetized dogs is highly variable and influenced by body position. This is most likely the result of anatomic interrelationships between the diaphragm, stomach, and terminal portion of the esophagus. Gastropexy also increases barrier pressure in the immediate postoperative period, which may be clinically relevant in terms of understanding how resolution of gastroesophageal reflux disease associated with hiatal hernia may be affected by gastropexy combined with hernia reduction.     

Gastric dilatation-volvulus in dogs

Gastric dilatation-volvulus (GDV) is a disease in which there is gross distension of the stomach with fluid or gas and gastric malpositioning. It causes pathology of multiple organ systems and is rapidly fatal. It is common in large- and giant-breed dogs. The disease appears to have a familial predisposition. Thoracic depth/width ratio also appears to predispose dogs to GDV. Implicated dietary factors include dietary particle size, frequency of feeding, speed of eating, aerophagia and an elevated feed bowl. A fearful temperament and stressful events may also predispose dogs to GDV. Abdominal distension, non-productive retching, restlessness, signs of shock, tachypnoea and dyspnoea are possible clinical signs. Initial treatment includes treatment of shock and gastric decompression. Surgical treatment should be performed promptly. There are no studies comparing the use of different anaesthetic agents in the anaesthetic management of GDV. Pre-medication with an opioid/benzodiazepine combination has been recommended. Induction agents that cause minimal cardiovascular changes such as opioids, neuroactive steroidal agents and etomidate are recommended. Anaesthesia should be maintained with an inhalational agent. Surgical therapy involves decompression, correction of gastric malpositioning, debridement of necrotic tissue, and gastropexy. Options for gastropexy include incisional, tube, circumcostal, belt-loop, incorporating, and laparoscopic gastropexy. Expected mortality with surgical therapy is 15-24%. Prognostic factors include mental status on presentation, presence of gastric necrosis, presence of cardiac arrhythmia and plasma lactate levels. Prophylactic gastropexy should be considered in dogs identified as being at high risk.     

Comparison of the Recurrence Rate of Gastric Dilatation with or Without Volvulus in Dogs after Circumcostal Gastropexy Versus Gastrocolopexy

OBJECTIVE: To compare the recurrence rate of acute gastric dilatation with or without volvulus (GDV) after circumcostal gastropexy (CCGP) or gastrocolopexy (GCP) in dogs. STUDY DESIGN: A prospective, double-blind, multicenter, randomized, controlled, clinical trial with two groups (A and B). ANIMALS: Fifty-four client-owned dogs presented for treatment of GDV. METHODS: Dogs with acute GDV that had not previously had a gastropexy performed were included. The preoperative treatment before gastropexy was standardized. A CCGP was performed on dogs in group A, and a GCP was performed on dogs in group B. Postoperative treatment was standardized, but deviation did occur according to the special needs of particular patients. A minimal follow-up time of 180 days was required for dogs not excluded from the study. The median follow-up time in group A was 700 days; in group B, it was 400 days. The occurrence of abdominal pain and gastrointestinal problems after surgery were recorded by the owners. RESULTS: There was no significant difference in the recurrence rate of GDV between the two groups. At the end of the study, the recurrence rate was 9% and 20% in group A and in group B, respectively. CONCLUSIONS: Both surgical techniques are effective in preventing recurrence of GDV.     

Gastric dilatation-volvulus in dogs

Gastric dilatation-volvulus (GDV) is a disease in which there is gross distension of the stomach with fluid or gas and gastric malpositioning. It causes pathology of multiple organ systems and is rapidly fatal. It is common in large- and giant-breed dogs. The disease appears to have a familial predisposition. Thoracic depth/width ratio also appears to predispose dogs to GDV. Implicated dietary factors include dietary particle size, frequency of feeding, speed of eating, aerophagia and an elevated feed bowl. A fearful temperament and stressful events may also predispose dogs to GDV. Abdominal distension, non-productive retching, restlessness, signs of shock, tachypnoea and dyspnoea are possible clinical signs. Initial treatment includes treatment of shock and gastric decompression. Surgical treatment should be performed promptly. There are no studies comparing the use of different anaesthetic agents in the anaesthetic management of GDV. Pre-medication with an opioid/benzodiazepine combination has been recommended. Induction agents that cause minimal cardiovascular changes such as opioids, neuroactive steroidal agents and etomidate are recommended. Anaesthesia should be maintained with an inhalational agent. Surgical therapy involves decompression, correction of gastric malpositioning, debridement of necrotic tissue, and gastropexy. Options for gastropexy include incisional, tube, circumcostal, belt-loop, incorporating, and laparoscopic gastropexy. Expected mortality with surgical therapy is 15–24%. Prognostic factors include mental status on presentation, presence of gastric necrosis, presence of cardiac arrhythmia and plasma lactate levels. Prophylactic gastropexy should be considered in dogs identified as being at high risk.     

Occurrence and recurrence of gastric dilatation with or without volvulus after incisional gastropexy

This study investigated recurrence of gastric dilatation without (GD) or with volvulus (GDV) after incisional gastropexy (IG) in dogs that underwent IG for prevention of GDV. Signalment, concurrent surgical procedures, presence of GD or GDV at the time of IG were obtained from medical records of dogs that underwent IG. Owners were contacted to determine whether the dogs experienced GD or GDV after IG, dates of postoperative GD or GDV episodes, survival status, date of death for deceased dogs. Gastric dilatation and GDV recurrence rates were calculated for 40 dogs that had at least 2 y follow-up from the time when IG was performed and for dogs that experienced GD or GDV during the follow-up period. No dogs experienced GDV after IG and 2 dogs (5.0%) experienced GD after IG. The results suggest that GD and GDV rates after IG may be comparable to recurrence rates after other methods of gastropexy.