pHmetria esofágica e influência da metoclopramida e da ranitidina na prevenção dos episódios de refluxo gastroesofágico em cães anestesiados, submetidos a ovariosalpingohisterectomia eletiva

• Autor(a) principal: Favarato, Evandro Silva
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1444
• topic: Cães; Refluxo gastroesofágico; Metoclopramida; Dogs; Gastroesophageal reflux; Metoclopramide; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA

This work was divided into two subprojects, with the first being titled Ambulatory esophageal pHmetry in healthy dogs with and without the influence of general anesthetics , and the second, Influence of metoclopramide and ranitidine on prevention of gastroesophageal reflux episodes in anesthetized dogs . The first subproject aimed to determine the esophageal pH value in adult healthy dogs submitted to general anesthetics and unanesthetized (conscious), to evaluate the esophageal pH value in unanesthetized dogs in different body positions, as well as to assess the occurrence of gastroesophageal reflux episodes in these positions. Thus, 40 healthy male and female dogs with mean body weight of 14.24±8.1 kg were used. Esophageal pHmetry was performed in 10 unanesthetized dogs using a cateter by transnasal approach. The pH value in these animals was recorded every minute for 8 hours. During this period, the animals were allowed to move freely and the body positioning changes (lateral and sternal decubitus and quadrupedal position) were duly recorded. Esophageal pHmetry was also carried out in 30 female dogs anesthetized with acepromazine, propofol and isoflurane and submitted to elective ovariosalpingohisterectomy. In these animals, esophageal pH variations were recorded throughout the anesthetic procedure by inserting the cateter through the oropharynx. Esophagoscopy was carried out after the surgical procedure to investigate the presence of refluid content and guarantee the correct positioning of the cateter. The second subproject aimed to evaluate the effect of metoclopramide and ranitidine on the prevention of gastroesophageal reflux episodes during the anesthetic procedures. For this case, 90 healthy female dogs, with mean age of 2.9±2.29, submitted to elective ovariosalpingohisterectomy were used. The animals were randomly divided into three groups of 30 animals, and received infusion of saline solution (control group), bolus (1 mg/kg) and continuous infusion of metoclopramide (1 mg/kg/h) (metoclopramide group) and ranitidine bolus (2 mg/kg), 6 hours before anesthesia (ranitidine group). Similarly to the first subproject, anesthesia was standardized with acepromazine, propofol and isoflurane, and the esophageal pH variations were recorded throughout the anesthetic procedure, with the cateter inserted through the oropharynx. Esophagoscopy was also carried out after surgery. The mean esophageal pH value was lower (p<0.01) in the anesthetized dogs (7.3±0.82) than in the unanesthetized ones (8.2±0.3). Only four anesthetized dogs (13.33%) presented reflux episodes and esophagoscopy identified all the refluxes, being particularly important in confirming non acid reflux. No reflux episode was observed in the unanesthetized dogs, with no esophageal pH difference being observed among the body positions studied. No difference (p>0.05) was found in the number of dogs presenting gastroesophageal reflux episodes during anesthesia among the groups tested. Seven dogs presented reflux, with four from the control group, two from the ranitidine group and one from the metoclopramide group. Of these animals, four presented acid reflux, and three non acid reflux. Esophagoscopy identified all the refluxes, being particularly important in confirming non acid reflux. General anesthesia in dogs, using the earlier mentioned anesthetic protocol, leads to the reduction of esophageal pH. Metoclopramide in bolus and continuous infusion, as well as ranitidine 6 hours before anesthesia did not have an important influence on reducing the incidence of gastroesophageal reflux. Esophageal pHmetry is efficient in confirming ac id reflux, but esophagoscopy performed immediately after the surgical procedure is fundamental to confirm non acid reflux. Eight-hour esophageal pHmetry with transnasal cateter passage is easy to perform, with few complications in unanesthetized dogs. Esophageal pH is alkaline in unanesthetized healthy dogs submitted to fast and does not vary according to body positioning.