Validação biofísica do método transvesical para medição da Pressão Intra-abdominal
Miniatura indisponível
Data
2016
Título da revista
ISSN da revista
Título do Volume
Editora
Resumo
O aumento da Pressão Intra-Abdominal (PIA) é um fenómeno bem documentado cujas repercussões fisiopatológicas podem levar a alterações em todos os sitsemas de órgaos, aumentando a morbilidade e mortalidade de doentes em cuidados intensivos.
Embora a medição deste parâmetro em Medicina Veterinária (MV) ainda não seja frequentemente utilizado na monitorização dos doentes, em Medicina Humana (MH), a monitorização da PIA tem-se revelado um importante indicador de prognóstico em doentes com diversas condições clínicas. Uma vez que os métodos de medição directa da PIA, para além de invasivos, são também dispendiosos, geralmente recorre-se a métodos indirectos na sua mensuração, tal como a manometria intra-gástrica ou transvesical.
Embora o tema da fiabilidade dos métodos de medição indirecta da PIA, ainda se encontre envolto em controvérsia, o método de eleição tanto em MH como em MV continua a ser o método transvesical.
O presente estudo tem como objectivo a validação do método transvesical através da aplicação de conceitos biofísicos, abrindo desta forma portas para uma melhor compreensão, aplicação e interpretação dos resultados obtidos.
O estudo foi realizado num modelo de cadáver animal da cavidade abdominal, de forma a erradicar algumas das variáveis passíveis de alterar a medição da PIA. A PIA foi medida por dois métodos diferentes numa população de 29 cadáveres de cão. Todas as componentes físicas envolvidas na formação da PIA foram determinadas, tal como o peso, Área de Superfície da Cavidade Abdominal (ASCA) e a força exercida pelas estruturas abdominais. Através dos princípios da física clássica e da mecânica de fluidos desenvolveu-se uma sobreposição de princípios biofísicos. Esta formulação permitiu a substituição dos valores determinados em cadáveres de forma a determinar a PIA por métodos físicos. Os valores calculados foram posteriormente comparados com os valores da PIA obtidos pelo método directo por sensor e pelo método transvesical.
A comparação dos valores calculados pela formulação biofísica com os valores determinados pelo método directo e pelo método transvesical não revelaram diferenças estatisticamente significativas (P <0,05). Deste modo pode-se concluir que o método transvesical apresenta um nível de precisão adequado à sua utilização na prática clínica.
The increase in the Intra-Abdominal Pressure (IAP) is a well-documented phenomenon whose pathophysiological repercussions can lead to changes in all organic systems, increasing the morbidity and mortality of patients in intensive care. Although the measurement of this parameter in Veterinary Medicine (VM) is still not frequently used while monitoring patients, in Human Medicine (HM), its assessment has shown to be an important prognostic factor in patients with several clinical conditions. Given the methods for direct measurement of the IAP are, besides being of an invasive character, of high cost, it is common practice to use indirect methods in its measurement, such as the intra-gastric manometry and the transvesical method. Even though the reliability of the IAP measurement using indirect methods is still a controversial issue, the most applied and considered the gold standard in both VM and HM is still the transvesical method. This study’s main goal is the validation of the transvesical method by applying biophysical concepts, providing this way a better understanding, application and interpretation of the obtained results. The study was performed in an animal model of the abdominal cavity, in order to eradicate some of the variables which could alter the IAP measurement. The IAP was measured using three different methods throughout a population of 29 dog cadavers. All the physical components involved in the IAP development were determined, as well as the weight, Abdominal Cavity Surface Area (ACSA) and the force exerted by the abdominal structures. Using classic physics’ and Fluids Mechanics’ principles, an overlap of bio-physical principles was developed. This formulation allowed replacing data obtained in cadavers in order to determine the IAP using physical methods. The calculated values were further compared with IAP values obtained using the direct method with sensor and with the transvesical method. The comparison between the values obtained using the bio-physical formulation and the values determined by the direct method and the transvesical method did not reveal statistically significant differences (P<0.05). By this, one can conclude that the transvesical method presents an adequate accuracy level which allows its usage in clinical practice.
The increase in the Intra-Abdominal Pressure (IAP) is a well-documented phenomenon whose pathophysiological repercussions can lead to changes in all organic systems, increasing the morbidity and mortality of patients in intensive care. Although the measurement of this parameter in Veterinary Medicine (VM) is still not frequently used while monitoring patients, in Human Medicine (HM), its assessment has shown to be an important prognostic factor in patients with several clinical conditions. Given the methods for direct measurement of the IAP are, besides being of an invasive character, of high cost, it is common practice to use indirect methods in its measurement, such as the intra-gastric manometry and the transvesical method. Even though the reliability of the IAP measurement using indirect methods is still a controversial issue, the most applied and considered the gold standard in both VM and HM is still the transvesical method. This study’s main goal is the validation of the transvesical method by applying biophysical concepts, providing this way a better understanding, application and interpretation of the obtained results. The study was performed in an animal model of the abdominal cavity, in order to eradicate some of the variables which could alter the IAP measurement. The IAP was measured using three different methods throughout a population of 29 dog cadavers. All the physical components involved in the IAP development were determined, as well as the weight, Abdominal Cavity Surface Area (ACSA) and the force exerted by the abdominal structures. Using classic physics’ and Fluids Mechanics’ principles, an overlap of bio-physical principles was developed. This formulation allowed replacing data obtained in cadavers in order to determine the IAP using physical methods. The calculated values were further compared with IAP values obtained using the direct method with sensor and with the transvesical method. The comparison between the values obtained using the bio-physical formulation and the values determined by the direct method and the transvesical method did not reveal statistically significant differences (P<0.05). By this, one can conclude that the transvesical method presents an adequate accuracy level which allows its usage in clinical practice.
Descrição
Orientação : Pedro Faísca ; co-orientação : António Martinho
Palavras-chave
MESTRADO INTEGRADO EM MEDICINA VETERINÁRIA, VETERINÁRIA, PRESSÃO INTRA-ABDOMINAL, MECÂNICA DE FLUIDOS, INTRA-ABDOMINAL PRESSURE, FLUID MECHANICS, MEDICINA VETERINÁRIA, VETERINARY MEDICINE