Ayrton Ponce de Souza

Subdiaphragmatic venous stasis and tissular hypoperfusion as sources of metabolic acidosis during passive portal-jugular and caval-jugular bypasses in dogs

Subdiafragmatic venous decompression during anhepatic stage of canine orthotopic liver transplantation attenuates portal and caval blood stasis and minimize hipoperfusion and metabolic acidosis observed with occlusion of portal and caval veins. During two hours, six dogs submitted to portal-jugular and caval-jugular passive shunts, with maintenance of arterial hepatic flow, were evaluated for pH, carbon dioxide tension (PCO2), base deficit (BD) and oxygen tension (PO2) in portal, caval and systemic arterial blood, as well as for increments of BD (DBD) in portal and caval blood. With a confidence level of 95%, the results showed that: 1. There were not changes of pH anDBD in portal and systemic arterial blood in the majority of studied times; 2. There was metabolic acidosis in caval blood; 3. The negative increments of BD (DBD) were higher in caval blood than in splancnic venous blood at T10, T30 and T105; and, 4. Deoxigenation of portal and caval blood were detected. Acid-base metabolism and oxigenation monitoring of subdiaphramatic venous blood can constitute an effective way to evaluate experimental passive portal-jugular and caval-jugular bypass in dogs.

Desvios porta-jugular e cava-jugular passivos em cães: Investigação de pressões sangüíneas

The main purposes of veno-venous bypasses during orthotopic liver transplantation are: attenuation of subdiaphragmatic venous stasis, maintenance of satisfactory venous return to the heart, and efficient tissue perfusion. PVP, IHIVCP, CVP, MAP and RPP, as well as D PVP and D IHIVCP were investigated in six dogs, under general anesthesia, having their livers perfused by hepatic artery, and submitted to passive porto-jugular and cava-jugular shunts during two hours. Such shunts, were not able to obviate stagnation of blood in portal and caval veins, inducing stasis and lesser venous return to the heart, as suggested by increases of PP and PVCIIH and decreases of CVP values. Levels of MAP were not significantly different from those verified at T0, in the majority of studied times, and RPP values were significantly decreased from those at T0, in almost all instances. Such pressures were respectively maintained above 100 and 50 mmHg, and were attributed in part to a widespread arteriolar vasoconstriction. Pressure increments in PV (D PVP) were significantly smaller than those verified in the IHIVC (D IHIVCP), and such difference was attributed to splancnic compliance. Further decreases in PP and IHIVCP levels suggest a lower arterial flux to splancnic and systemic territories as a consequence of reduced venous return to the heart. PVP, IHIVCP, CVP, MAP and RPP determinations may comprise a practical mean to assist hemodynamic veno-venous bypass performance.

Cystic dilatation of the common bile duct in adults: report of five cases and review of literature

Os autores apresentam cinco casos de dilatacao cistica do ducto biliar comum do Tipo I (classificacao de Todani) em adultos, anteriormente nao relatados, num periodo de 25 anos no Servico de Cirurgia Geral de um Hospital Universitario, entre 16.057 operacoes, no periodo de 1974 e 1999. O diagnostico dos cistos foi realizado atraves de colangiografia operatoria (CO) no primeiro, por colangiografia transparietohepatica no segundo (CTPH) e por ultra-sonografia (US), colangiopancreatografia endoscopica retrograda (CPER) and colangiografia operatoria (CO), respectivamente, nos tres ultimos casos. Em um dos pacientes, foi detectado adenocarcinoma localizado na parede posterior do cisto, associado a metastases peritoniais. Os dois primeiros casos foram tratados atraves de derivacao cistoenterica, sendo nos tres ultimos realizada a excisao do cisto, seguida de hepaticojejunostomia em Y de Roux. Foram revisados classificacao, incidencia, etiologia, diagnostico, malignizacao e tratamento cirurgico da doenca cistica biliar (DCB), concluindo-se que a terapeutica cirurgica de escolha deve ser a resseccao, quando possivel, sobretudo devido ao risco significativo de malignizacao.

Um novo modelo para estudos sobre lesão de isquemia e reperfusão hepáticas em cães

Hepatic ischaemia and reperfusion injury, as seen during hepatic transplantation, has not been completely understood. Several experimental models have been proposed for studies on pathophysiology and modulation of such condition. Recently, in dogs, partial hepatic devascularization (30%) with splancnic venous decompression using translobar venous route of intact lobes (70%) has been proposed. Inthe present paper , a larger hepatic mass (70%) has been devascularized in 10 dogs submitted to splancnic venous decompression through caudate and right lateral lobes (30%), during the ischaemic period( Test Group), followed by reperfusion. Ten others animals were submitted to a sham operation( Control Group). The results indicated, with a confidence level of 95% that: 1. During the period of ischaemia it was demonstrated maintenance of MAP and CVP levels, elevation of PP values similar to that seen with bypass, core temperature (CT) decrease that never reached limits under the mean value of 36oC, absence of metabolic acidosis or elevation of enzyme levels (AST, ALT and DL), occurrence of hepatic necrosis (HN) and fall in hepatic glycogen content (HGC); 2. After reperfusion, reduced values of MAP, absence of significant differences in CVP levels, persistent elevations of PP, progressive decreases in CT levels, presence of metabolic acidosis (¯ pH, ¯ DB), progressive elevations of aminotranspherases (AST, ALT) , lactic dehidrogenase (LD) and hepatic necrosis (HN), and progressive decline of hepatic glycogen content (HGC) were verified. These results suggest that the proposed model may be useful for studies on pathophysiology and pharmacologic modulation of liver ischaemia and reperfusion injury , using a larger hepatic mass.

Lesão de isquemia e reperfusão hepáticas em cães. Estudos histológicos sobre necrose hepatocítica, conteúdo de glicogênio hepático e contagem tecidual de polimorfonucleares

In the liver transplantation pathophysiology of hepatic ischaemia and reperfusion lesion is not completely understood. Several experimental models have been used to perform studies on tissue hipoxia and reperfusion of the liver. The present work, presents a modified model proposed to evaluate this kind of lesion. Twenty mongrel dogs, weighting 15.25 ± 1.21 kg, under general anesthesia, were referred to the following investigation groups: 1. Test Group (n = 10) - Animals were submitted to devascularization of 70 per cent of hepatic mass during a ninety minutes period, followed by liver reperfusion. During the time of ischaemia, splancnic venous decompression was provided through the right lateral and caudate lobes; 2. Control Group (n = 10) - The dogs were submitted to a sham operation. Liver samples were taken at 5 minutes before ischaemia (T0) 5 minutes before reperfusion (T1) and I hour (T2) and 5 hours (T3) after hepatic reperfusion. The method was evaluated by hepatic cells necrosis (HCN), hepatic glycogen content (HGC) and tissue polymorphonuclear cells counting (PMNCC). The results showed with a 95 per cent of confidence that: I. There was a progressive rise in HCN intensity and a fall in HGC, during the hepatic ischaemia and reperfusion stages; 2. There was no evidence of significant differences in PMNCC between the investigated groups. The verified histologic change are expression of effective HCN derived from liver isquemia and reperfusion.