No description available.

No description available.

The pathogenesis of duodenal ulcer is believed to centre around the presence of gastric acid, yet the exact role that acid plays is poorly understood. Previous investigations of the duodenal pH have been restricted by methodological and technical difficulties, and have, for the most part, only monitored the pH in the short-term. A new reliable system for long-term (twenty-four hour), ambulatory, simultaneous measurement of intra-luminal antral and duodenal bulb pH has been developed. The system comprises two glass pH electrodes, a small portable recording unit and a computer-based system for data storage and analyses. Validation of this pH monitoring system was first performed, and the 24-hour ambulatory profiles of antral and duodenal pH of normal healthy subjects were subsequently recorded. Periods of cephalic stimulation and ingestion of a solid meal were included during the study period. Having established the normal profiles, the investigation was repeated in patients with active duodenal ulcer, off-treatment. The gastric pH profile was similar of both study groups. There were no significant differences between the fasting duodenal bulb pH and the total 24-hour duodenal acid exposure of the ulcer patients and healthy subjects. Acid peak analysis demonstrated that the duodenal ulcer patients exhibited a defect in the propulsive duodenal bulb motility. Gastric stimulation caused a similar pattern of duodenal acidification in the two groups. These results suggest that gastric acid is not of primary pathophysiological importance in duodenal ulcer disease. The effects of cephalic stimulation and a meal on plasma gastrin, secretin and somatostatin and duodenal pH were examined in healthy subjects and duodenal ulcer patients. The results showed: vagally-released gastrin is not a significant contributor to stimulation of gastric acid secretion in either health or duodenal ulcer disease; duodenal ulcer patients have excessive basal and post-stimulation plasma gastrin levels but a subset of ulcer patients exists, the "Hypergastrinaemic" patients, who exhibit exaggerated gastrin responses, vagal hyperactivity, a defective somatostatin-induced inhibition of gastrin release and a defect in the "switch-off" mechanism of gastric acid secretion. In addition, the physiological role of secretin in inhibiting gastrin release in Man is questionable. This study reveals new aspects in the physiology and pathophysiology of the duodenal bulb pH.

No description available.

No description available.

Made available in DSpace on 2015-01-26T13:21:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-14Bitstream added on 2015-01-26T13:30:41Z : No. of bitstreams: 1 000793012.pdf: 590115 bytes, checksum: ed882cd22177020eacb824774d3bea52 (MD5) / Introdução - Apesar de controvérsias, a máscara laríngea passou a ser utilizada em larga escala em laparoscopias. Nas ginecológicas, em especial, que têm no aumento da pressão intra-abdominal, associado à posição de céfalo-declive empregada durante o procedimento, fatores com potencial de risco de provocar regurgitação de conteúdo gástrico, com possibilidade de comprometimento de vias aéreas, faz-se necessária uma avaliação para a ocorrência de tal fenômeno. Objetivo - Avaliar a segurança do uso da máscara laríngea, em laparoscopia ginecológica, com relação ao risco de regurgitação de conteúdo gástrico, medindo o pH das secreções de hipofaringe, durante o procedimento anestésico-cirúrgico. Método - Foram avaliadas 80 pacientes submetidas à anestesia geral para laparoscopia ginecológica, com acesso a via aérea garantida pelo uso da máscara laríngea ProSeal (MLA-ProSeal). As secreções da hipofaringe foram coletadas por aspiração através do tubo de drenagem esofágica, para medida do pH, em vários momentos do ato anestésico-cirúrgico. Utilizamos as fitas medidoras de pH de 2 a 9 – Merck, Darmstadt – Alemanha e um ph-metro de bancada foi utilizado em caso de dúvidas. O pH ≤ 4,1 foi considerado como positivo para regurgitação de conteúdo gástrico. Resultados - Após análise das medidas do pH das secreções de hipofaringe, não se encontrou nenhum valor de pH ≤ 4,1. O pH das secreções variou com médias de 6,34 a 6,50 nos diversos momentos medidos, compatível com o pH normal da saliva. Conclusão - Com os resultados obtidos, concluiu-se que a máscara laríngea ProSeal é uma alternativa segura para a realização do ato anestésico em cirurgia laparoscópica, nos pacientes que não apresentem fatores de risco para regurgitação de conteúdo gástrico / Introduction: Although controversial, the laryngeal mask is now widely used for laparoscopies. In gynecological laparoscopy, in particular, there is an increase in the intra-abdominal pressure associated with the head-down position used during the procedure and an increase in the potential risk factors for the regurgitation of gastric contents with the potential to compromise the airways, and therefore, the occurrence of such phenomena during gynecological laparoscopy needs to be evaluated. Objectives - To evaluate the safety of using a ProSeal laryngeal mask airway (LMA-P) during gynecological laparoscopy, assessing the risk of regurgitation of gastric contents by measuring the pH of secretions in the hypopharynx during the anesthetic/surgical procedure. Methods - In total, 80 patients were evaluated who were under general anesthesia for gynecological laparoscopy in which airway access was maintained using a ProSeal laryngeal mask airway. Secretions in the hypopharynx were collected by aspiration using an esophageal drainage tube to measure their pH at various times during the anesthetic/surgical procedure. We used pH test strips, pH 2-9 (Merck, Darmstadt, Germany), and in case of any doubts, a pH meter was also used. A pH of ≤ 4.0 was considered positive for the regurgitation of gastric contents. Results - None of the pH measurements of analyzed secretions in the hypopharynx had a pH of ≤ 4.0. The mean pH of the secretions varied from 6.34 for the lower means to 6.50 for the higher means when measured at different time points, which are comparable to the normal pH of saliva. Conclusion - From these results, we conclude that the ProSeal laryngeal mask airway is a safe alternative for anesthesia during laparoscopic surgery for patients without risk factors for the regurgitation of gastric contents

Orientador: Norma Sueli Pinheiro Módolo / Banca: Leandro Gobbo Braz / Banca: Vera Lúcia Fernandes de Azevedo / Resumo: Introdução - Apesar de controvérsias, a máscara laríngea passou a ser utilizada em larga escala em laparoscopias. Nas ginecológicas, em especial, que têm no aumento da pressão intra-abdominal, associado à posição de céfalo-declive empregada durante o procedimento, fatores com potencial de risco de provocar regurgitação de conteúdo gástrico, com possibilidade de comprometimento de vias aéreas, faz-se necessária uma avaliação para a ocorrência de tal fenômeno. Objetivo - Avaliar a segurança do uso da máscara laríngea, em laparoscopia ginecológica, com relação ao risco de regurgitação de conteúdo gástrico, medindo o pH das secreções de hipofaringe, durante o procedimento anestésico-cirúrgico. Método - Foram avaliadas 80 pacientes submetidas à anestesia geral para laparoscopia ginecológica, com acesso a via aérea garantida pelo uso da máscara laríngea ProSeal (MLA-ProSeal). As secreções da hipofaringe foram coletadas por aspiração através do tubo de drenagem esofágica, para medida do pH, em vários momentos do ato anestésico-cirúrgico. Utilizamos as fitas medidoras de pH de 2 a 9 - Merck, Darmstadt - Alemanha e um ph-metro de bancada foi utilizado em caso de dúvidas. O pH ≤ 4,1 foi considerado como positivo para regurgitação de conteúdo gástrico. Resultados - Após análise das medidas do pH das secreções de hipofaringe, não se encontrou nenhum valor de pH ≤ 4,1. O pH das secreções variou com médias de 6,34 a 6,50 nos diversos momentos medidos, compatível com o pH normal da saliva. Conclusão - Com os resultados obtidos, concluiu-se que a máscara laríngea ProSeal é uma alternativa segura para a realização do ato anestésico em cirurgia laparoscópica, nos pacientes que não apresentem fatores de risco para regurgitação de conteúdo gástrico / Abstract: Introduction - Although controversial, the laryngeal mask is now widely used for laparoscopies. In gynecological laparoscopy, in particular, there is an increase in the intra-abdominal pressure associated with the head-down position used during the procedure and an increase in the potential risk factors for the regurgitation of gastric contents with the potential to compromise the airways, and therefore, the occurrence of such phenomena during gynecological laparoscopy needs to be evaluated. Objectives - To evaluate the safety of using a ProSeal laryngeal mask airway (LMA-P) during gynecological laparoscopy, assessing the risk of regurgitation of gastric contents by measuring the pH of secretions in the hypopharynx during the anesthetic/surgical procedure. Methods - In total, 80 patients were evaluated who were under general anesthesia for gynecological laparoscopy in which airway access was maintained using a ProSeal laryngeal mask airway. Secretions in the hypopharynx were collected by aspiration using an esophageal drainage tube to measure their pH at various times during the anesthetic/surgical procedure. We used pH test strips, pH 2-9 (Merck, Darmstadt, Germany), and in case of any doubts, a pH meter was also used. A pH of ≤ 4.0 was considered positive for the regurgitation of gastric contents. Results - None of the pH measurements of analyzed secretions in the hypopharynx had a pH of ≤ 4.0. The mean pH of the secretions varied from 6.34 for the lower means to 6.50 for the higher means when measured at different time points, which are comparable to the normal pH of saliva. Conclusion - From these results, we conclude that the ProSeal laryngeal mask airway is a safe alternative for anesthesia during laparoscopic surgery for patients without risk factors for the regurgitation of gastric contents / Mestre

Additional appendix (5 p.) is pasted onto back end-paper. / Bibliography: leaves 219-244. / v, 244, [14] p., 67 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the complexity of the vagal reflexes arising from the upper gastrointestinal tract by recording single unit vagal afferents and efferents in the ferret. The potential involvement of various neurotransmitters in mediating and modulating gastrointestinal tract inputs is also explored. / Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 1999

Additional appendix (5 p.) is pasted onto back end-paper. Bibliography: leaves 219-244. Investigates the complexity of the vagal reflexes arising from the upper gastrointestinal tract by recording single unit vagal afferents and efferents in the ferret. The potential involvement of various neurotransmitters in mediating and modulating gastrointestinal tract inputs is also explored.