New technique for intrathoracic implantation of extraluminal spiral prostheses in the trachea

Background: Extraluminal surgical procedures for intrathoracic tracheal collapse in dogs are not routinely performed. The patients are normally treated with different drugs or by intraluminal stents. However, in more severe cases, drug treatment does not always have good outcomes, and intraluminal prostheses can be correlated to several postoperative problems. In order to obtain better results, we aimed to develop a surgical technique for implantation of a new extraluminal helical prosthesis in the thoracic segment of the trachea through cervical access, associated with pneumatic mediastinoscopy for certification of the technique and minimization of possible complications. Materials, Methods & Results: Seven canine corpses (CCs) from non-traumatic death, weighing between 2 and 7 kg, were used. A ventral cervical approach to the trachea was associated with blunt mediastinal dissection. Trans cervical pneumatic mediastinoscopy was used for evaluation of the dissection and location of the implant. These were compared with the necropsy findings by the exact Wilcoxon two-sample test, with P < 0.05. The results of necropsy and mediastinoscopy did not present significant differences at P < 0.05. During the examinations, the presence of some mediastinal visceral le-sions caused by the prosthesis, the integrity of the mediastinum and possible lesions to RLN and blood vessels (BV) were analyzed. We also investigated the location of the distal part of the prosthesis in the thoracic segment of the trachea and its dissection. To evaluate the technique, statistical comparison was made between mediastinoscopy and necropsy find-ings. The data were compared by the Wilcoxon test at 5% probability. The tracheas of all CCs were efficiently dissected, but in some cases problems that can happen during the procedure were noticed. This was checked by mediastinoscopy and confirmed by necropsy. The median of the scores was...(AU)

New technique for intrathoracic implantation of extraluminal spiral prostheses in the trachea

Background: Extraluminal surgical procedures for intrathoracic tracheal collapse in dogs are not routinely performed. The patients are normally treated with different drugs or by intraluminal stents. However, in more severe cases, drug treatment does not always have good outcomes, and intraluminal prostheses can be correlated to several postoperative problems. In order to obtain better results, we aimed to develop a surgical technique for implantation of a new extraluminal helical prosthesis in the thoracic segment of the trachea through cervical access, associated with pneumatic mediastinoscopy for certification of the technique and minimization of possible complications. Materials, Methods & Results: Seven canine corpses (CCs) from non-traumatic death, weighing between 2 and 7 kg, were used. A ventral cervical approach to the trachea was associated with blunt mediastinal dissection. Trans cervical pneumatic mediastinoscopy was used for evaluation of the dissection and location of the implant. These were compared with the necropsy findings by the exact Wilcoxon two-sample test, with P < 0.05. The results of necropsy and mediastinoscopy did not present significant differences at P < 0.05. During the examinations, the presence of some mediastinal visceral le-sions caused by the prosthesis, the integrity of the mediastinum and possible lesions to RLN and blood vessels (BV) were analyzed. We also investigated the location of the distal part of the prosthesis in the thoracic segment of the trachea and its dissection. To evaluate the technique, statistical comparison was made between mediastinoscopy and necropsy find-ings. The data were compared by the Wilcoxon test at 5% probability. The tracheas of all CCs were efficiently dissected, but in some cases problems that can happen during the procedure were noticed. This was checked by mediastinoscopy and confirmed by necropsy. The median of the scores was...

Efeitos da clonidina e da rilmenidina sobre os sistemas cardiorrespiratório e gastrointestinal de equinos / Effects of clonidine and rilmenidine on cardiorespiratory and gastrointestinal systems of horses

Clonidine and rilmenidine are drugs used in human medicine as central acting antihypertensive agents due to their actions on the alpha2-adrenoceptor and I1 imidazoline receptors in the central nervous system. Currently, clonidine is also used as a pre-anesthetic medication and in spinal anesthesia, and rilmenidine, despite the lower selectivity for alpha2-adrenergic receptors than clonidine, has also shown antinociceptive potential in experimental pain models. In this study, six horses were submitted to four treatments: R1 group (0.014 mg/kg of rilmenidine); R2 group (0.021 mg/kg of rilmenidine); Clo group (0.002 mg/kg of clonidine), and a control group. The assessment comprehended their heart and respiratory rates, systolic blood pressure and intestinal motility at basal levels and, then, 60 and 120 minutes after the oral administration of the drugs. Rilmenidine decreased heart rate on   the two tested doses, which did not occur in the clonidine treatment; slight variations in systolic blood pressure in all treatments and respiratory rate reduction in treatments with rilmenidine at 0.021 mg/ kg and clonidine at 0.002 mg/kg were also observed. Further studies with different dosages and varied administration routes are still necessary in order to elucidate more effects of these drugs on horses.

Clonidina e rilmenidina são fármacos utilizados em medicina humana como agentes anti-hipertensivos de ação central devido às suas ações sobre os receptores alfa2-adrenérgicos e imidazolínicos I1 no SNC. Atualmente a clonidina é também utilizada como medicação pré-anestésica e em anestesias espinhais e a rilmenidina, apesar da menor seletividade pelo receptor alfa2-adrenérgico, também tem demonstrado potencial antinociceptivo em modelos experimentais de dor. Neste estudo, seis equinos foram submetidos a quatro tratamentos: grupo R1 (0,014 mg/kg de rilmenidina); grupo R2 (0,021 mg/ kg de rilmenidina); grupo Clo (0,002 mg/kg de clonidina) e um grupo controle. Foram avaliadas as frequências cardíaca e respiratória, a pressão arterial sistólica e motilidade intestinal em níveis basais e, em seguida, 60 e 120 minutos após a administração oral dos fármacos. A rilmenidina reduziu a frequência cardíaca nas duas doses testadas, o que não ocorreu com a clonidina; variações discretas na pressão arterial sistólica em todos os tratamentos e redução na frequência respiratória nos tratamentos com 0,021 mg/kg de rilmenidina e 0,002 mg/kg de clonidina também foram observadas. São ainda necessários maiores estudos com doses e vias de administração diferentes para se elucidar maiores efeitos destes fármacos na espécie equina.

Efeitos da clonidina e da rilmenidina sobre os sistemas cardiorrespiratório e gastrointestinal de equinos / Effects of clonidine and rilmenidine on cardiorespiratory and gastrointestinal systems of horses

Clonidine and rilmenidine are drugs used in human medicine as central acting antihypertensive agents due to their actions on the alpha2-adrenoceptor and I1 imidazoline receptors in the central nervous system. Currently, clonidine is also used as a pre-anesthetic medication and in spinal anesthesia, and rilmenidine, despite the lower selectivity for alpha2-adrenergic receptors than clonidine, has also shown antinociceptive potential in experimental pain models. In this study, six horses were submitted to four treatments: R1 group (0.014 mg/kg of rilmenidine); R2 group (0.021 mg/kg of rilmenidine); Clo group (0.002 mg/kg of clonidine), and a control group. The assessment comprehended their heart and respiratory rates, systolic blood pressure and intestinal motility at basal levels and, then, 60 and 120 minutes after the oral administration of the drugs. Rilmenidine decreased heart rate on   the two tested doses, which did not occur in the clonidine treatment; slight variations in systolic blood pressure in all treatments and respiratory rate reduction in treatments with rilmenidine at 0.021 mg/ kg and clonidine at 0.002 mg/kg were also observed. Further studies with different dosages and varied administration routes are still necessary in order to elucidate more effects of these drugs on horses. (AU)

Clonidina e rilmenidina são fármacos utilizados em medicina humana como agentes anti-hipertensivos de ação central devido às suas ações sobre os receptores alfa2-adrenérgicos e imidazolínicos I1 no SNC. Atualmente a clonidina é também utilizada como medicação pré-anestésica e em anestesias espinhais e a rilmenidina, apesar da menor seletividade pelo receptor alfa2-adrenérgico, também tem demonstrado potencial antinociceptivo em modelos experimentais de dor. Neste estudo, seis equinos foram submetidos a quatro tratamentos: grupo R1 (0,014 mg/kg de rilmenidina); grupo R2 (0,021 mg/ kg de rilmenidina); grupo Clo (0,002 mg/kg de clonidina) e um grupo controle. Foram avaliadas as frequências cardíaca e respiratória, a pressão arterial sistólica e motilidade intestinal em níveis basais e, em seguida, 60 e 120 minutos após a administração oral dos fármacos. A rilmenidina reduziu a frequência cardíaca nas duas doses testadas, o que não ocorreu com a clonidina; variações discretas na pressão arterial sistólica em todos os tratamentos e redução na frequência respiratória nos tratamentos com 0,021 mg/kg de rilmenidina e 0,002 mg/kg de clonidina também foram observadas. São ainda necessários maiores estudos com doses e vias de administração diferentes para se elucidar maiores efeitos destes fármacos na espécie equina. (AU)

EFEITOS DA CLONIDINA E DA RILMENIDINA SOBRE OS SISTEMAS CARDIORRESPIRATÓRIO E GASTROINTESTINAL DE EQUINOS

Abstract: Clonidine and rilmenidine are drugs used in human medicine as central acting antihypertensive agents due to their actions on the alpha2-adrenoceptor and I1 imidazoline receptors in the central nervous system. Currently, clonidine is also used as a pre-anesthetic medication and in spinal anesthesia, and rilmenidine, despite the lower selectivity for alpha2-adrenergic receptors than clonidine, has also shown antinociceptive potential in experimental pain models. In this study, six horses were submitted to four treatments: R1 group (0.014 mg/kg of rilmenidine); R2 group (0.021 mg/kg of rilmenidine); Clo group (0.002 mg/kg of clonidine), and a control group. The assessment comprehended their heart and respiratory rates, systolic blood pressure and intestinal motility at basal levels and, then, 60 and 120 minutes after the oral administration of the drugs. Rilmenidine decreased heart rate on the two tested doses, which did not occur in the clonidine treatment; slight variations in systolic blood pressure in all treatments and respiratory rate reduction in treatments with rilmenidine at 0.021 mg/kg and clonidine at 0.002 mg/kg were also observed. Further studies with different dosages and varied administration routes are still necessary in order to elucidate more effects of these drugs on horses.

Resumo: Clonidina e rilmenidina são fármacos utilizados em medicina humana como agentes anti-hipertensivos de ação central devido às suas ações sobre os receptores alfa2-adrenérgicos e imidazolínicos I1 no SNC. Atualmente a clonidina é também utilizada como medicação pré-anestésica e em anestesias espinhais e a rilmenidina, apesar da menor seletividade pelo receptor alfa2-adrenérgico, também tem demonstrado potencial antinociceptivo em modelos experimentais de dor. Neste estudo, seis equinos foram submetidos a quatro tratamentos: grupo R1 (0,014 mg/kg de rilmenidina); grupo R2 (0,021 mg/kg de rilmenidina); grupo Clo (0,002 mg/kg de clonidina) e um grupo controle. Foram avaliadas as frequências cardíaca e respiratória, a pressão arterial sistólica e motilidade intestinal em níveis basais e, em seguida, 60 e 120 minutos após a administração oral dos fármacos. A rilmenidina reduziu a frequência cardíaca nas duas doses testadas, o que não ocorreu com a clonidina; variações discretas na pressão arterial sistólica em todos os tratamentos e redução na frequência respiratória nos tratamentos com 0,021 mg/kg de rilmenidina e 0,002 mg/kg de clonidina também foram observadas. São ainda necessários maiores estudos com doses e vias de administração diferentes para se elucidar maiores efeitos destes fármacos na espécie equina.