ABSTRACT Purpose: To determine whether dexmedetomidine aggravates hemodynamic, metabolic variables, inflammatory markers, and microcirculation in experimental septic shock. Methods: Twenty-four pigs randomized into: Sham group (n = 8), received saline; Shock group (n = 8), received an intravenous infusion of Escherichia coli O55 (3 × 109 cells/mL, 0.75 mL/kg, 1 hour); Dex-Shock group (n = 8), received bacteria and intravenous dexmedetomidine (bolus 0.5 mcg/kg followed by 0.7 mcg/kg/h). Fluid therapy and/ornorepinephrine were administered to maintain a mean arterial pressure > 65 mmHg. Hemodynamic, metabolic, oxygenation, inflammatory markers, and microcirculation were assessed at baseline, at the end of bacterial infusion, and after 60, 120, 180, and 240 minutes. Results: Compared to Shock group, Dex-Shock group presented a significantly increased oxygen extraction ratio at T180 (23.1 ± 9.7 vs. 32.5 ± 9.2%, P = 0.0220), decreased central venous pressure at T120 (11.6 ± 1 vs. 9.61 ± 1.2 mmHg, P = 0.0214), mixed-venous oxygen saturation at T180 (72.9 ± 9.6 vs. 63.5 ± 9.2%, P = 0.026), and increased plasma lactate (3.7 ± 0.5 vs. 5.5 ± 1 mmol/L, P = 0.003). Despite the Dex-Shock group having a better sublingual vessel density at T240 (12.5 ± 0.4 vs. 14.4 ± 0.3 mL/m2; P = 0.0003), sublingual blood flow was not different from that in the Shock group (2.4 ± 0.2 vs. 2.4 ± 0.1 mL/kg, P = 0.4418). Conclusions: Dexmedetomidine did not worsen the hemodynamic, metabolic, inflammatory, or sublingual blood flow disorders resulting from septic shock. Despite inducing a better sublingual vessel density, dexmedetomidine initially and transitorily increased the mismatch between oxygen supply and demand.

RESUMO: A oclusão dos anéis inguinais é o tratamento indicado para evitar as hérnias inguinais comumente observadas nos equinos. O objetivo do trabalho é avaliar a eficácia do uso de enxerto de pericárdio homólogo para recobrimento do anel inguinal interno de equinos, fixado por laparoscopia, comparando a sutura manual e mecânica. Para tanto, foram utilizados seis equinos machos não castrados da raça Mangalarga com idade entre 3 e 12 anos. Os cavalos foram operados sob anestesia geral em posição de Trendelenburg com inclinação de 25º. Cinco portais laparoscópicos foram empregados. Enxertos de pericárdio homólogo, medindo 4X5cm, foram ancorados recobrindo os anéis inguinais internos esquerdo e direito, sendo em um dos lados fixado com sutura manual intracorpórea e o contralateral fixado com grampos, escolhidos por sorteio previamente ao procedimento, distribuído equitativamente. Os cavalos foram acompanhados por 11 semanas do período pós-operatório. O tempo cirúrgico, eventuais complicações trans ou pós-operatórias e a efetividade do procedimento foram avaliados e analisados estatisticamente com nível de significância de 5% P<0,05. Os procedimentos foram realizados sem complicações, com tempo médio requerido para realização da sutura manual e com grampos de 67,8±15,3 e 14,1±2,1 minutos, respectivamente, havendo diferença significativa P<0,05. Todos os implantes suturados manualmente levaram à oclusão do anel inguinal profundo, enquanto houve deiscência parcial da sutura, com incompleta oclusão do anel, em dois dos seis implantes fixados por sutura mecânica, na avaliação aos 77 dias. Não ocorreram complicações significativas no período trans ou pós-operatório, sendo observada a presença de uma sinéquia e três aderências de omento durante laparoscopia de controle aos 77 dias, porém sem relevância clínica no período estudado. O uso de pericárdio homólogo foi efetivo para oclusão do anel vaginal em equinos por laparoscopia. A sutura mecânica foi realizada em menor tempo, quando comparada à sutura manual, porém propiciou resultado menos satisfatório no que diz respeito à segurança da técnica para fixação do enxerto.

ABSTRACT: The occlusion of inguinal ring is the treatment to avoid the inguinal hernia in horses. The aim of this study is evaluate the efficacy of homologous pericardium grafts for internal inguinal ring closure in horses, comparing mechanical or manual laparoscopic suture. Cross over study, using six healthy intact male Mangalarga breed horses aged between 3 and 12 years. Horses were operated under general anesthesia in 25º Trendelenburg position. Five laparoscopic portals were employed. Pericardium grafts measuring 4x5cm were anchored covering the left and right internal inguinal rings using either manual intracorporeal suture or laparoscopic stapler. Horses were followed-up during 11 weeks when were submitted to a laparoscopic control. Surgical time, trans and postoperative complications and effectiveness of internal inguinal closure were evaluated and statistically analyzed. The level of significance was set at 5% P<0.05. The procedures were realized without complications and the mean time required for manual and mechanical suture procedures differed significantly (67.8±15.3 and 14.1±2.1 min respectively; P<0.05). All manually sutured grafts remained in place and partial suture dehiscence with incomplete occlusion of the internal inguinal ring was observed in two stapled grafts. Non-severe complications were observed trans or postoperatively. One synechiae and three omental adhesions were observed by laparoscopic control on day 77, but without clinical relevance in the evaluated period. The use of homologous pericardium grafts was effectiveness to internal inguinal ring closure by laparoscopy. Mechanical suture was faster to perform than manual, but provided less satisfactory results concerning safety of graft fixation.

OBJECTIVES: Inhalant anesthesia induces dose-dependent cardiovascular depression, but whether fluid responsiveness is differentially influenced by the inhalant agent and plasma volemia remains unknown. The aim of this study was to compare the effects of isoflurane, sevoflurane and desflurane on pulse pressure variation and stroke volume variation in pigs undergoing hemorrhage. METHODS: Twenty-five pigs were randomly anesthetized with isoflurane, sevoflurane or desflurane. Hemodynamic and echocardiographic data were registered sequentially at minimum alveolar concentrations of 1.00 (M1), 1.25 (M2), and 1.00 (M3). Then, following withdrawal of 30% of the estimated blood volume, these data were registered at a minimum alveolar concentrations of 1.00 (M4) and 1.25 (M5). RESULTS: The minimum alveolar concentration increase from 1.00 to 1.25 (M2) decreased the cardiac index and increased the central venous pressure, but only modest changes in mean arterial pressure, pulse pressure variation and stroke volume variation were observed in all groups from M1 to M2. A significant decrease in mean arterial pressure was only observed with desflurane. Following blood loss (M4), pulse pressure variation, stroke volume variation and central venous pressure increased (p<0.001) and mean arterial pressure decreased in all groups. Under hypovolemia, the cardiac index decreased with the increase of anesthesia depth in a similar manner in all groups. CONCLUSION: The effects of desflurane, sevoflurane and isoflurane on pulse pressure variation and stroke volume variation were not different during normovolemia or hypovolemia.