Fabíola Niederauer Flôres

Dexmedetomidina epidural em gatas submetidas à ovariosalpingohisterectomia sob anestesia total intravenosa com propofol e pré-medicadas com cetamina S(+) e midazolam

The objective of this study was to evaluate the effect of the epidural administration of dexmedetomidine in cats submitted to ovariohisterectomy, under continuous infusion of propofol. The cats received S(+) ketamine (5mg kg-1) and midazolan (0.5mg kg-1) as premedication by intramuscular injection, and propofol as induction agent (4mg kg-1), by intravenous injection. After that, the cats were intubated and kept on oxygen 100%. Subsequently the continuous infusion of propofol was initiated (0.3mg kg-1 min-1). The animals were divided into two groups, in the dexmedetomidine group (DEXG, n=6,2µg kg-1) dexmedetomidine was administered by epidural injection, and in the control group (SALG, n=6) saline solution was administered by the same way. In both groups the final volume was 0.26 mL kg-1 completed with NaCl 0.9%. Fentanyl administration was necessary at T10 in 33.3% of the patients. During the continuous infusion of propofol, the medial palpebral reflex was present in 66.6% of the animals of SALG and in 16.6% of the animals of DEXG. The eyeball was centralized in all the animals of SALG and 83.4% of the animals of DEXG the eyeball were with ventral rotation. Reduction of the heart rate was observed after anesthesia induction in both groups. The mean arterial pressure was significantly lesser at T0 and T5 in the DEXG and greater at T10 in the SALG when compared to the basal values. The respiratory rate was lesser in the DEXG at T20 and T30 when compared to SALG. The SaO2 and PaO2 were bigger from T5 to T40. The PaCO2 bigger values were observed at T5, T10, T20, T30 and T40 for the DEXG and at T5, T10 and T20 in the SALG when compared to the basal values. In the anesthetic recovery, 50% and 16.6% of the animals presented aggressiveness in the SALG and DEXG, respectively. To the wound pain threshold, it was observed that 33.3% of animals of SALG and 66.7% of the animals of DEXG received score 0 (without reaction). It was concluded that the animals that received dexmedetomidine administration by epidural injection, presented more stable anesthetic plan with greater analgesia degree in the peri and postoperative period, better quality anesthesia recovery, and without significant cardiovascular and hemogasometric changes.

Azaperone e sua associação com xilazina ou dexmedetomidina em suínos

The aim of this study was to evaluate the sedative effects of azaperone and its association with xylazine or dexmedetomidine in swine, as well as verifying the possibility of the butyrophenone agent to counterbalance the effects caused by α2-adreneceptor agonists on the cardiovascular and hemodynamic parameters. For this, eighteen healthy swines of the Dambread X MS 50 lineage aged 50 days-old, weighing around 17.3kg (±1.7) were used. All animals were submitted an isoflurane anesthesia by face mask throughout the period of instrumentation. Basal parameters were measured 30 minutes after recovering from general anesthesia. All swines were randomly assigned into three groups of six animals each: AG (azaperone 2mg kg-1 + sodium chloride 0.5ml - IM), ADG (azaperone 2mg kg-1 + dexmedetomidine 3µg kg-1 - IM) and AXG (azaperone 2mg kg-1 + xylazine 2mg kg-1 - IM). Parameters were again measured at the following times: 15, 30, 45 and 60 minutes after administrating the corresponding drugs to each group. The heart rate had its values reduced in all groups; however this reduction was more significative in AXG. During the study was not observed a biphasic effect over the arterial pressure with an initial increase followed by a gradual decrease. AXG presented reduction of PaO2 and an increase in PaCO2 as well as a better sedative effect. The results allow to conclude that the association of azaperone with xylazine promoted a better tranquilization and muscular relaxation.

Efeitos cardiovascular e metabólico da reposição volêmica com hidroxietilamido 130/0,4 em felinos domésticos com hipovolemia induzida

The aim of this study was to compare the volemic expansion effects produced by hydroxyethyl starch 130/0.4 (HES 130/0.4) or blood, in female cats with induced hypovolemia. Twelve healthy adult female cats, crossbreed and weighing an average of 2.85±0.28kg were used. They were induced into general anesthesia with isofluorane at 5V%, intubated and connected to a non-rebreathing system. After instrumentation, the animals were maintained under anesthesia with isofluorane at 1.3V% and maintained on pressure cycled mechanic ventilation. Afterwards, hypovolemia was induced by withdrawal of 30ml kg-1 of blood from the femoral artery. After 60 minutes of stabilization of the patient, the treatments were initiated. In the hydroxyethyl starch group (GH, n=06) the animals received hydroxyethyl starch 130/0.4 as volemic expansion at the same volume of blood withdrawed, in the blood group (GS, n=06) the animals received their own withdrawed blood, being considered the control group. The systolic, diastolic and mean arterial pressures and central venous pressure increased after volemic expansion in both groups. An increase of PaCO2 at T15, T30 and T60 in GH was observed. In addition, there was reduction of pH at T30 and T45 and Na+ ions at T90 in GH. The arterial pressure restoration with the use of HES 130/0.4 was similar to the control group; the volemic expansion with HES 130/0,4 produces accentuated increase of CVP; the use of HES 130/0,4 in female cats submitted to hypovolemia did not produce clinically significant alterations in acid-base equilibrium.

Sulfato de atropina nos parâmetros hemodinâmicos e hemogasométricos de cães anestesiados com clorpromazina, dexmedetomidina e isoflurano

Seis caes, pesando 17,9kg (±3,9), foram anestesiados em duas ocasioes, com intervalo de sete dias, obedecendo estudo cego. A inducao e a manutencao anestesica foram realizadas com isoflurano em ventilacao mecânica. Depois da instrumentacao, a concentracao final de isoflurano foi fixada em 1,3V% durante o estudo. Apos periodo de estabilizacao de 30 minutos, foram mensurados os parâmetros hemodinâmicos e hemogasometricos (M-15); na sequencia, administrou-se atropina (grupo atropina) ou cloreto de sodio 0,9% (grupo salina). Passados 15 minutos, os parâmetros foram avaliados novamente (M0) e aplicou-se clorpromazina e dexmedetomidina (Clor-Dex). As variaveis foram mensuradas por mais 65 minutos depois da Clor-Dex. Empregou-se ANOVA de uma via e teste Student Newman Keuls para valores entre tempos dentro de cada grupo e teste t pareado para avaliacao das medias entre grupos (P£0,05). A frequencia cardiaca foi maior no grupo atropina depois da administracao de Clor-Dex, e houve reducao nos valores de Indice Cardiaco (IC) em ambos os grupos. Embora os valores medios de IC tenham sido maiores no grupo atropina, nao houve diferenca significativa entre grupos administracao de Clor-Dex promoveu aumento da pressao arterial em caes tratados com atropina. A pressao arterial media (PAM) foi significativamente maior no grupo atropina dos 5 aos 65 minutos apos administracao de Clor-Dex, assim como o Indice de Resistencia Periferica Total (IRPT) aumentou em ambos os grupos depois da Clor-Dex.. Os parâmetros hemogasometricos nao apresentaram diferencas significativas. A administracao de atropina antes da clorpromazina e da dexmedetomidina resultou em aumento da pressao arterial. A bradicardia induzida pela administracao da associacao de farmacos foi prevenida pelo anticolinergico, porem a reducao do debito cardiaco nao foi prevenida.

Epidural administration of ropivacaine or ropivacaine and xylazine in cattle

Protocolos epidurais sao comumente utilizados em bovinos, possibilitando inclusive a realizacao de procedimentos cirurgicos com o animal em posicao quadrupedal, no entanto, problemas como paresia e decubito, alem do tempo de bloqueio/recuperacao sao fatores importantes na escolha do protocolo. O objetivo deste estudo foi avaliar dois protocolos de anestesia epidural em bovinos, quanto ao tempo, qualidade de bloqueio e efeitos clinicos. Foram utilizadas 14 vacas mesticas, com peso medio de 350±170 kg, as quais foram alocadas em dois grupos: ropivacaina (GR, n=7) onde os animais receberam a administracao epidural de ropivacaina (0,1 mg.kg-1) e ropivacaina/xilazina (GRX, n=7) que receberam ropivacaina e xilazina (0,075 e 0,05 mg.kg-1, respectivamente) pela mesma via. Avaliou-se: frequencia cardiaca (FC), frequencia respiratoria ( f ), pressao arterial media (PAM), movimentos ruminais (MR), temperatura retal (TR), tempo de duracao do bloqueio anestesico (TB), qualidade do bloqueio (QB) atraves da resposta a estimulos nociceptivos pelo clampeamento perineal, grau de paresia (GP) e hemogasometria arterial. Os animais foram avaliados por ate 420 minutos apos a administracao. A FC, f, PAM, pH, PaCO2, Na+, Ca++, HCO3 - e Excesso de Base (EB) nao diferiram entre grupos. Foi observada uma leve diminuicao nos movimentos ruminais e aumento da PaO2 e TR no GRX comparado ao GR. A duracao do bloqueio sensitivo foi de 6 e 7 horas para o GR e GRX, respectivamente. A QB foi considerada boa/excelente frente a estimulacao nociceptiva em 66% e 71% dos animais do GR em M360 e do GRX em M420. Os animais do GRX apresentaram sinais de paresia moderada a grave de M15 ate M240. Conclui-se que a ropivacaina associada a xilazina pela via epidural apresenta bloqueio sensitivo mais prolongado do que a ropivacaina isolada, no entanto a associacao com a xilazina promove bloqueio motor, com sinais de paresia, devendo ser utilizada com cautela em bovinos.

Cianose e metahemoglobinemia associada à deficiência de NADH-metahemoglobina redutase em um cão sob anestesia

This study reports the occurrence of cyanosis in a dog under general anesthesia. The patient didn’t present any sign of heart or respiratory disease, the accidental ingestion of oxidizers agents wasn’t possible. Therefore resulting the suspicion of metahemoglobinemia associated to the deficiency of NADH-metahemoglobina redutase. This was confirmed after suggestive test and laboratorial specific test.