Made available in DSpace on 2014-06-11T19:23:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-26Bitstream added on 2014-06-13T18:19:51Z : No. of bitstreams: 1 canola_pa_me_jabo.pdf: 427975 bytes, checksum: 2a024bc0f4f2c221e49f30e64f898189 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Na rotina hospitalar, são numerosos os casos clínicos em que se faz necessária a intervenção cirúrgica da cavidade abdominal em eqüinos, seja por meio da realização de laparotomias ou de laparoscopias, a qual vem se intensificando com o passar dos anos, na tentativa de serem minimizados os riscos e o trauma cirúrgicos. Desta forma, torna-se importante o conhecimento das alterações causadas pela entrada de ar na cavidade abdominal sobre a mecânica respiratória. Com o estudo objetivou-se avaliar a influência do pneumoperitôneo sobre a pressão pleural (Ppl), parâmetros cardiovasculares e hemogasométricos em oito eqüinos, averiguar a relação entre a pressão gástrica (Pga) e a pressão abdominal (Pab) e estimar os valores da pressão transdiafragmática (PTr) para esta espécie. Não houve alteração (p>0,05) da Ppl, parâmetros hemogasométricos, da FC, FR, PAS e PVC após a instauração do pneumoperitôneo passivo com ar atmosférico. Houve variação (p 0,05) dos valores da PAD e PAM e da temperatura retal (To) após instauração do discreto pneumoperitôneo e o aumento da To pareceu estar mais relacionado à fatores estressantes do que ao aumento da pressão abdominal. A pressão transdiafragmática (PTr) foi calculada com base na fórmula Ptr = Pab – Ppl. Com base nos resultados obtidos pode ser concluído que o pneumoperitôneo passivo não altera a Ppl, os parâmetros cardiovasculares e hemogasométricos em eqüinos. Não foi observada relação entre os valores da pressão gástrica (Pga) e da pressão abdominal (Pab), portanto o método de aferição indireta da pressão abdominal é ineficaz para estimar os valores reais da Pab e a pressão transdiafragmática apresenta valores negativos para a espécie eqüina. / In the hospital routine there are a large number of clinical cases in which surgical intervention of the abdominal cavity is needed in horses, or by laparotomy, or by laparoscopy, which has increased its used by the past few years, as an effort to minimize the risks and surgical trauma. In that way it is important to understand the mechanical changes caused by the air entrance into the abdominal cavity. The objectives of study were to evaluate the influence of the pneumoperitoneum on pleural pressure (Ppl); cardiovascular and hemogasometric parameters in eight horses, investigate the relationship between the gastric pressure (Pga) and the abdominal pressure (Pab) and to estimate the transdiaphragmatic pressure (PTr) values for this species. There were no changes (p>0,05) in the Ppl, hemogasometric parameters, FC, FR, PAS and PVC after the instauration of the passive pneumoperitoneum with atmospheric air. There were changes (p>0,05) in PAD, PAM and body temperature (To) values after instauration of the de discrete pneumoperitoneum, and the changes in To seemed to be more related with the stressful conditions than with the increase in abdominal pressure. The transdiaphragmatic pressure (PTr) was calculated using the formula Ptr = Pab – Ppl. Based in the results obtained the passive pneumoperitoneum did not change Ppl, the cardiovascular and hemogasometric parameters in horses. There was no relationship between the gastric pressure (Pga) and abdominal pressure (Pab) so the indirect method for the abdominal pressure measurement is not capable of estimating the real values of the Pab, and the transdiaphragmatic pressure values are negative in horses.

Resumo: Na rotina hospitalar, são numerosos os casos clínicos em que se faz necessária a intervenção cirúrgica da cavidade abdominal em eqüinos, seja por meio da realização de laparotomias ou de laparoscopias, a qual vem se intensificando com o passar dos anos, na tentativa de serem minimizados os riscos e o trauma cirúrgicos. Desta forma, torna-se importante o conhecimento das alterações causadas pela entrada de ar na cavidade abdominal sobre a mecânica respiratória. Com o estudo objetivou-se avaliar a influência do pneumoperitôneo sobre a pressão pleural (Ppl), parâmetros cardiovasculares e hemogasométricos em oito eqüinos, averiguar a relação entre a pressão gástrica (Pga) e a pressão abdominal (Pab) e estimar os valores da pressão transdiafragmática (PTr) para esta espécie. Não houve alteração (p>0,05) da Ppl, parâmetros hemogasométricos, da FC, FR, PAS e PVC após a instauração do pneumoperitôneo passivo com ar atmosférico. Houve variação (p 0,05) dos valores da PAD e PAM e da temperatura retal (To) após instauração do discreto pneumoperitôneo e o aumento da To pareceu estar mais relacionado à fatores estressantes do que ao aumento da pressão abdominal. A pressão transdiafragmática (PTr) foi calculada com base na fórmula Ptr = Pab - Ppl. Com base nos resultados obtidos pode ser concluído que o pneumoperitôneo passivo não altera a Ppl, os parâmetros cardiovasculares e hemogasométricos em eqüinos. Não foi observada relação entre os valores da pressão gástrica (Pga) e da pressão abdominal (Pab), portanto o método de aferição indireta da pressão abdominal é ineficaz para estimar os valores reais da Pab e a pressão transdiafragmática apresenta valores negativos para a espécie eqüina. / Abstract: In the hospital routine there are a large number of clinical cases in which surgical intervention of the abdominal cavity is needed in horses, or by laparotomy, or by laparoscopy, which has increased its used by the past few years, as an effort to minimize the risks and surgical trauma. In that way it is important to understand the mechanical changes caused by the air entrance into the abdominal cavity. The objectives of study were to evaluate the influence of the pneumoperitoneum on pleural pressure (Ppl); cardiovascular and hemogasometric parameters in eight horses, investigate the relationship between the gastric pressure (Pga) and the abdominal pressure (Pab) and to estimate the transdiaphragmatic pressure (PTr) values for this species. There were no changes (p>0,05) in the Ppl, hemogasometric parameters, FC, FR, PAS and PVC after the instauration of the passive pneumoperitoneum with atmospheric air. There were changes (p>0,05) in PAD, PAM and body temperature (To) values after instauration of the de discrete pneumoperitoneum, and the changes in To seemed to be more related with the stressful conditions than with the increase in abdominal pressure. The transdiaphragmatic pressure (PTr) was calculated using the formula Ptr = Pab - Ppl. Based in the results obtained the passive pneumoperitoneum did not change Ppl, the cardiovascular and hemogasometric parameters in horses. There was no relationship between the gastric pressure (Pga) and abdominal pressure (Pab) so the indirect method for the abdominal pressure measurement is not capable of estimating the real values of the Pab, and the transdiaphragmatic pressure values are negative in horses. / Orientador: Carlos Augusto Araújo Valadão / Coorientador: César Augusto Melo e Silva / Banca: Luis Cláudio Lopes Correia da Silva / Banca: Juliana Regina Peiró / Mestre

Background: Global and regional transpulmonary pressure (PL) during one-lung ventilation (OLV) is poorly characterized. We hypothesized that global and regional PL and driving PL (ΔPL) increase during protective low tidal volume OLV compared to two-lung ventilation (TLV), and vary with body position. Methods: In sixteen anesthetized juvenile pigs, intra-pleural pressure sensors were placed in ventral, dorsal, and caudal zones of the left hemithorax by video-assisted thoracoscopy. A right thoracotomy was performed and lipopolysaccharide administered intravenously to mimic the inflammatory response due to thoracic surgery. Animals were ventilated in a volume-controlled mode with a tidal volume (VT) of 6 mL kg⁻¹ during TLV and of 5 mL kg⁻¹ during OLV and a positive end-expiratory pressure (PEEP) of 5 cmH₂O. Global and local transpulmonary pressures were calculated. Lung instability was defined as end-expiratory PL<2.9 cmH₂O according to previous investigations. Variables were acquired during TLV (TLVsupine), left lung ventilation in supine (OLVsupine), semilateral (OLVsemilateral), lateral (OLVlateral) and prone (OLVprone) positions randomized according to Latin-square sequence. Effects of position were tested using repeated measures ANOVA. Results: End-expiratory PL and ΔPL were higher during OLVsupine than TLVsupine. During OLV, regional end-inspiratory PL and ΔPL did not differ significantly among body positions. Yet, end-expiratory PL was lower in semilateral (ventral: 4.8 ± 2.9 cmH₂O; caudal: 3.1 ± 2.6 cmH₂O) and lateral (ventral: 1.9 ± 3.3 cmH₂O; caudal: 2.7 ± 1.7 cmH₂O) compared to supine (ventral: 4.8 ± 2.9 cmH₂O; caudal: 3.1 ± 2.6 cmH2O) and prone position (ventral: 1.7 ± 2.5 cmH₂O; caudal: 3.3 ± 1.6 cmH₂O), mainly in ventral (p ≤ 0.001) and caudal (p = 0.007) regions. Lung instability was detected more often in semilateral (26 out of 48 measurements; p = 0.012) and lateral (29 out of 48 measurements, p < 0.001) as compared to supine position (15 out of 48 measurements), and more often in lateral as compared to prone position (19 out of 48 measurements, p = 0.027). Conclusion: Compared to TLV, OLV increased lung stress. Body position did not affect stress of the ventilated lung during OLV, but lung stability was lowest in semilateral and lateral decubitus position.