Dissertação (mestrado)—Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, 2014. / Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2014-09-01T13:03:01Z No. of bitstreams: 1 2014_MariaLuizaMeloDias.pdf: 1129653 bytes, checksum: f409ba87c5ce8bd0353253ac8da3965a (MD5) / Approved for entry into archive by Guimaraes Jacqueline(jacqueline.guimaraes@bce.unb.br) on 2014-09-09T14:20:55Z (GMT) No. of bitstreams: 1 2014_MariaLuizaMeloDias.pdf: 1129653 bytes, checksum: f409ba87c5ce8bd0353253ac8da3965a (MD5) / Made available in DSpace on 2014-09-09T14:20:55Z (GMT). No. of bitstreams: 1 2014_MariaLuizaMeloDias.pdf: 1129653 bytes, checksum: f409ba87c5ce8bd0353253ac8da3965a (MD5) / A síndrome braquicefálica caracteriza-se pelo aumento da resistência à passagem do ar nas vias aéreas superiores, devido a combinações de deformidades anatômicas como estenose de narinas, alongamento de palato mole, eversão de sáculos laríngeos e hipoplasia traqueal. Vinte cães braquicefálicos (GB) e 20 cães dolicocefálicos (GC), com até cinco anos de idade, foram incluídos no estudo. Avaliaram-se pressão arterial sistólica, média e diastólica, hemogasometria, ecodopplercardiografia, eletrocardiografia, eletrocardiografia ambulatorial, hematimetria e radiografias torácica e cervical. A média ± desvio padrão da abertura da narina no GB foi estatisticamente menor comparado ao GC (0,23 ± 0,08 cm versus 0,56 ± 0,05 cm, p < 0,001). A SaO2 foi menor no GB (p < 0,001) e a pressão arterial média foi maior no GB (p = 0,05). Todos os cães braquicefálicos apresentaram arritmia sinusal (AS) e 15 (75%) destes tinham AS maior que 20% de variação entre intervalo RR adjacente, enquanto no GC, 17 (85%) animais apresentaram AS e 13 (65%) destes demonstraram AS maior que 20% de variação entre intervalo RR adjacente. A [HCO3-]v e PvCO2 foram maiores no GB (p < 0,001). Resultados deste estudo sugerem que cães braquicefálicos jovens já apresentam menor SaO2 e maior pressão arterial média quando comparados com cães dolicocefálicos. ______________________________________________________________________________ ABSTRACT / The brachycephalic syndrome is characterized by increased upper airway resistance to airflow due to combinations of anatomical deformities such as stenotic nares, elongation of the soft palate, eversion of the laryngeal saccules and tracheal hypoplasia. Twenty brachycephalic (BG) and 20 dolicocephalic dogs (CG), aged up to five years, were included in the study. Systolic (SAP), mean (MAP), and diastolic (DAP) arterial blood pressure recordings were recorded. Blood gases and complete blood count (CBC) were measured. Doppler echocardiography, electrocardiography, ambulatory electrocardiography as well as thoracic and cervical radiographs were evaluated. The mean ± standard deviation diameter of the nares was significantly lower in BG compared to CG (0.23 ± 0.08 versus 0.56 ± 0.05 cm, p < 0.001). The SaO2 was lower (p < 0.001) and mean arterial pressure higher in BG (p = 0.05). All brachycephalic dogs had sinus arrhythmia (SA), and 15 (75 %) of these showed more than 20 % variation between adjacent R-R intervals, whereas in CG, 17 (85 %) of the animals presented SA and 13 (65 %) of these showed more than 20 % variation between adjacent R-R intervals. Both [HCO3-]v and PvCO2 were higher in BG (p < 0.001). Results of this study suggest that young brachycephalic dogs already have lower SaO2 and higher MAP when compared with dolichocephalic dogs.