Pressão Intra-abdominal, Diâmetro e Índice de Colapsabilidade da Veia Cava Caudal em cães (CANIS LUPUS FAMILIARIS): valores fisiológicos

Abstract

Intra-abdominal pressure (PIA) is the force produced by the abdominal organs and the structures that harbor them. Maintaining the PIA in the appropriate physiological range guarantees abdominal perfusion, controls and prevents serious and sometimes irreversible and fatal organic dysfunctions. Its measurement is performed by indirect transvesical technique. In dogs the methodology for obtaining the IAP is not standardized, there are no reference values for dogs, with ideal body condition score (ECC) and in the absence of chemical containment. In addition to the IAP, systemic and abdominal perfusion can be assessed by measuring the caudal cava vein (VC) diameter and collapsibility index (IC), obtained quickly, practically and noninvasively using the ultrasound vascular examination, at the bedside. Such measurements have the potential to estimate hemodynamic and perfusional status in dogs dynamically and from different perspectives. In the search to find the ranges of normal values of the same and to understand their predictive variables, the PIA was evaluated in 66 dogs divided equally in three groups according to body weight. Group 1 consisted of dogs weighing less than 10 kilograms (kg), group 2 greater than or equal to 10 and less than 20 kg and group 3 greater or equal to 20 and less than 30 kg. As well as the biometric and hemodynamic variables related to VC in 25 others, which were also divided into three groups according to body weight, as mentioned above, but groups a, b and c composed of 9 (nine), 10 ( ten) and 6 (six) dogs, respectively. The dogs were attested as healthy by means of physical examination, ECC, blood count, biochemical profile and abdominal ultrasonography. The echocardiogram and urinary profile were added to these dogs in the dogs submitted to VCC vascular ultrasonographic evaluation and PIA measurement respectively. The IAP measurement was performed using the indirect transvesical method, under different volumes, decubits and measurement resources. The range of normal values for PIA found with the prediction degree of 95% for the gold standard (PO), that is, measurement performed in the dorsal decubitus, with 1.0 mL / kg of sodium chloride solution 0.9 %, transvesically infused and measured via the water column, was 0 to 7.5 mmHg, with an average of 3.09 ± 2.2 mmHg. It was observed that the sternal, right and left lateral decubitus overestimated the AIP values, similarly, by 1.3 mmHg in relation to the values obtained by the PO. As well as an overestimation of the IAP 10 values when using the volumes of 2.0 mL / kg of 0.97 mmHg and an underestimation of their values in 0.46 mmHg when using 0.5 mL / kg as compared to the PO. A direct correlation was verified between the PIA values and the ECC in dogs. Observing between female dogs with ECC 4 and 5, statistically different PIA ranges, which were 0-4.23 mmHg and 1.93-8.37 mmHg, respectively. For males, the same trend was observed, but no statistically significant difference was observed between ECC 4 and 5, with the observed ranges of values being 0 -5.77 mmHg and 0.91 7.41 mmHg, in the same order. Regarding the diameter and HF of the VCC, the analysis was made through the vascular ultrasound examination through the hepatic acoustic window, using the modes B and M. The ranges of normal values for the diameter and IC of the VCC in 6,27 ± 1,2 mm and 0,21 ± 0,10, respectively. The three methods of evaluation studied were applicable in the hospital routine in dogs, because they are simple and easy to perform, besides being fast and inexpensive. Therefore they present an important clinical and scientific potential. Since the veterinarian, having knowledge of values outside the normal ranges proposed for the PIA, diameter and IC of the VCC, may begin to suspect and investigate of systemic or focal changes in the perfusion and hemodynamics of the dogs.