Influence of intravenous fentanyl or dexmedetomidine infusions, combined with lidocaine and ketamine, on cardiovascular response, sevoflurane requirement and postoperative pain in dogs anesthetized for unilateral mastectomy.

OBJECTIVE: To compare the effects of constant rate infusions (CRI) of fentanyl or dexmedetomidine, combined with lidocaine and ketamine, on cardiovascular response during surgery, sevoflurane requirement and postoperative pain in dogs undergoing mastectomy. STUDY DESIGN: Prospective, randomized, blinded, clinical trial. ANIMALS: A total of 29 female dogs with mammary tumors. METHODS: Premedication consisted of intramuscular acepromazine and morphine. General anesthesia was induced with intravenous propofol and maintained with sevoflurane. Dogs were randomized to be administered intravenous DLK [dexmedetomidine 1 µg kg-1 loading dose (LD) and 1 µg kg-1 hour-1; lidocaine 2 mg kg-1 LD and 3 mg kg-1 hour-1; ketamine 1 mg kg-1 LD and 0.6 mg kg-1 hour-1; n = 14] or FLK (fentanyl 5 µg kg-1 LD and 9 µg kg-1 hour-1; same doses of lidocaine and ketamine; n = 15) during anesthesia. Cardiorespiratory variables and end-tidal sevoflurane (Fe'Sevo) were recorded during surgery. The number of dogs administered ephedrine to treat arterial hypotension [mean arterial pressure (MAP) < 60 mmHg] was recorded. Meloxicam was administered to both groups. Postoperative pain and rescue analgesia requirement were assessed for 24 hours using the short form of the Glasgow Composite Measure Pain Scale. Data were compared using a mixed effects model or a Mann-Whitney test. RESULTS: More dogs required ephedrine in FLK than in DLK (67% versus 7%). Heart rate was not significantly different between groups, whereas lower values of MAP (p ≤ 0.01) and Fe'Sevo (p = 0.018) were observed in FLK than in DLK. Rescue analgesia was administered to 2/15 dogs in FLK and 0/14 dogs in DLK. CONCLUSIONS AND CLINICAL RELEVANCE: Based on the cardiovascular response during surgery, intraoperative infusions of FLK and DLK provided adequate antinociception. Infusion of DLK provided greater stability of blood pressure. Both protocols resulted in minimal need for additional analgesia within 24 hours postoperatively.

Autonomic and hemodynamic effects of pre-anesthetic use of clonidine in healthy dogs.

The aim of this study was to evaluate the effects of pre-anesthetic use of clonidine on time-domain heart rate variability (HRV) and arterial blood pressure in healthy anesthetized dogs. Six healthy adult mixed-breed dogs were administered a clonidine (clonidine group, CLG) and 30 days later, a placebo (control group, CG) preanesthetic protocol, in addition to propofol, isoflurane, and an bolus of tramadol and the continuous infusion thereafter. The total time mean values of HRV meanNN, SDNN, SDANN, SDNNI, and rMSSD were higher in the CL group, as observed in some HRV variables on tramadol bolus time (T4), tramadol continuous infusion (T8), and tracheal extubation time (T10). No significant differences in arterial blood pressure were observed, however, two dogs had a second-degree atrioventricular block (Mobitz II) at the tramadol bolus time (T4). These results led us to conclude that the clonidine anesthetic protocol resulted in sympathetic outflow block and an increase in parasympathetic tone, without significant effects on blood pressure. Notably, cardiac electrical disturbance in two dogs in the CL group. Although the pre-anesthetic use of clonidine in dogs with fear-based behavioral problems should be considered, its association with tramadol should be avoided or carried out with caution owing to the existing cardiovascular risk.

Neste estudo objetivou-se avaliar os efeitos da administração pré-anestésica de clonidina na variabilidade da frequência cardíaca no domínio do tempo (VFC) e pressão arterial sanguínea de cães saudáveis anestesiados. Seis cães adultos hígidos, sem raça definida, foram submetidos a ambos protocolos anestésicos, com clonidina (grupo clonidina - GCL) e placebo (grupo controle - GC), associado ao propofol, isoflurano, bolus e infusão contínua de tramadol. Considerando o do tempo total de análise, os valores médios das variáveis de VFC NNmédio (GC=584.5±62.77, GCL=680.5±75.01), SDNN (GC=97.83±28.94, GCL=163.8±49.81), SDANN (GC=63.83±21.55, GCL=102.3±32.89), SDNNI (GC=60.83±28.53, GCL= 110.2±42.92) e rMSSD (GC=75.83±38.91, GCL=158.0±81.20) foram maiores no protocolo anestésico com clonidina, assim como também observado em algumas variáveis de VFC durante o tempo de administração do bolus (T4) (NNmédio: GC=643,70±123,10, GCL= 819,80±78,77) e infusão contínua (T8) (NNmédio: CG=599,20±35,66, CLG=785,00±52,13) de tramadol, assim como no tempo de extubação orotraqueal (T10) (NNmédio: GC=598,70±84,75, GCL=852,50±188,60; SDNN: GC=49,83±33,49, GCL=193,80±143,40; rMSSD: GC=43,50±33,86, GCL=314,20±294,60). Nenhuma diferença significativa na pressão arterial sanguínea foi observada, porém, dois cães apresentaram bloqueio atrioventricular de segundo grau (Mobitz II) no momento de aplicação do bolus de tramadol (T4). Assim, o protocolo anestésico com uso de clonidina resultou em bloqueio eferente simpático e aumento do tônus simpático, sem efeitos significativos sobre a pressão arterial, mas com ocorrência de distúrbio elétrico de condução cardíaco em dois cães. Embora o uso pré-anestésico de clonidina em cães com problemas comportamentais baseados no medo deva ser considerado, sua associação com tramadol deve ser evitada ou realizada com cautela devido ao risco cardiovascular existente.

Effects of dexmedetomidine or tramadol continuous rate infusions on the propofol requirements and cardiorespiratory variables in propofol-ketamine-midazolam anaesthetised cats.

The aim of this study was to compare the effects of midazolam-ketamine alone or in combination with dexmedetomidine or tramadol in a constant rate infusion (CRI) on the minimum infusion rate (MIR) of propofol and the cardiorespiratory function in cats undergoing an ovariohysterectomy (OH). This was a prospective, randomised, blinded clinical study. Twenty-four healthy female mixed-breed cats were premedicated with ketamine and midazolam. Propofol was used for the induction and maintenance of the anaesthesia (starting at 18 mg/kg/h). Cats were assigned to groups (n = 8) to receive one of the following intravenous treatments: midazolam-ketamine group (MKG; ketamine 0.6 mg/kg/h); midazolam-ketamine-dexmedetomidine group [MKDG; ketamine 0.6 mg/kg/h and dexmedetomidine loading dose (LD) 1 mg/kg, CRI 1 mg/kg/h)] or midazolam-ketamine-tramadol group [MKTG; ketamine 0.6 mg/kg/h and tramadol (LD 2 mg/kg, CRI 1 mg/kg/h)]. During the OH, the propofol infusion was adjusted based on the clinical signs to maintain adequate anaesthetic depth. Selected variables were measured before (T0) and after (T1) the anaesthesia induction and during six surgical time points (T2-T7). The mean arterial pressure was higher and the heart rate was lower in MKDG at T1 (than in MKG and MKTG). The mean ± SD MIR of propofol were 17.4 ± 3.2, 15.0 ± 2.8 and 12.6 ± 3.5 mg/kg/h for MKG, MKTG, and MKDG, respectively. We conclude that, compared to midazolam-ketamine alone, midazolam-ketamine-tramadol and midazolam-ketamine-dexmedetomidine reduced the MRI of propofol by 13.8% and 27.5%, respectively, without significant changes in the selected indicators.

Avaliação da anestesia epidural com lidocaína associada ao tramadol ou à dexmedetomidina, em gatas submetidas à ovariosalpingohisterectomia, anestesiadas com propofol / Evaluation of epidural anesthesia with lidocaine associated to tramadol or dexmedetomidine, in cats undergoing ovariosalpingohisterectomy, anesthetized with propofol

Objetivou-se comparar os efeitos fisiológicos, analgésicos e sobre a taxa de infusão de propofol, decorrentes da anestesia epidural com lidocaína, associada ao tramadol ou à dexmedetomidina, em felinas submetidas à ovariosalpingohisterectomia (OSH). Para tal, 16 felinas hígidas foram pré-tratadas com acepromazina 0,08mg/kg/IM, utilizando-se propofol para a indução (dose-efeito) e manutenção anestésicas. Após indução, as gatas foram aleatoriamente distribuídas em dois grupos (n=8), designados: grupo lidocaína-tramadol (GLT), tratado com lidocaína (3,0mg/kg) associada ao tramadol (2,0mg/kg); e grupo lidocaína-dexmedetomidina (GLD), tratado com lidocaína (3,0mg/kg) associada à dexmedetomidina (2µg/kg), pela via epidural. Durante a OSH, a infusão de propofol foi aumentada ou reduzida, objetivando-se manutenção de plano anestésico cirúrgico. Foram avaliados os parâmetros: f, FC, SPO2, EtCO2, PAS, PAD, PAM, T°C, nos períodos pré (M1) e transoperatórios (M2 a M7); a taxa mínima de propofol necessária; o tempo de recuperação anestésica e a qualidade da analgesia pós-cirúrgica durante seis horas. Ambos os tratamentos garantiram baixas taxas mínimas de infusão de propofol, todavia o uso da dexmedetomidina resultou em bradicardia inicial, elevação da pressão arterial, maior tempo de recuperação e menor qualidade analgésica, quando comparada ao tramadol.(AU)

The aim of this study was to compare the physiological and analgesic effects and the minimum infusion rate of propofol of epidural anesthesia with lidocaine associated to tramadol or dexmedetomidine, in cats undergoing ovariosalpingohysterectomy (OSH). For this purpose, 16 healthy cats were pretreated with acepromazine (0.08mg kg -1 IM) and propofol was used for induction (dose-effect) and maintenance of anesthesia. After induction, the cats were assigned in two randomized groups (n= 8), named: Lidocaine-tramadol group (LTG), treated with lidocaine (3mg kg -1 ) associated to tramadol (2mg kg -1 ) and Lidocaine-dexmedetomidine group (LDG), treated with lidocaine (3mg kg -1 ) associated to dexmedetomidine (2g kg -1 ), by epidural route. During OSH, propofol infusion was increased or decreased, setting to maintain surgical anesthetic depth. The parameters f, HR, SPO 2 , EtCO 2 , SAP, DAP, MAP, T°C in the pre (M1) and trans-operative periods (M2 to M7); minimum infusion rate of propofol; time of anesthetic recovery and quality of postoperative analgesia during six-hour interval, were evaluated. Both protocols provided low minimum infusion rate of propofol. However, dexmedetomidine resulted in initial bradycardia, elevated blood pressure, longer recovery time, and lower analgesic quality when compared to tramadol.(AU)

Avaliação da anestesia epidural com lidocaína associada ao tramadol ou à dexmedetomidina, em gatas submetidas à ovariosalpingohisterectomia, anestesiadas com propofol / Evaluation of epidural anesthesia with lidocaine associated to tramadol or dexmedetomidine, in cats undergoing ovariosalpingohisterectomy, anesthetized with propofol

Objetivou-se comparar os efeitos fisiológicos, analgésicos e sobre a taxa de infusão de propofol, decorrentes da anestesia epidural com lidocaína, associada ao tramadol ou à dexmedetomidina, em felinas submetidas à ovariosalpingohisterectomia (OSH). Para tal, 16 felinas hígidas foram pré-tratadas com acepromazina 0,08mg/kg/IM, utilizando-se propofol para a indução (dose-efeito) e manutenção anestésicas. Após indução, as gatas foram aleatoriamente distribuídas em dois grupos (n=8), designados: grupo lidocaína-tramadol (GLT), tratado com lidocaína (3,0mg/kg) associada ao tramadol (2,0mg/kg); e grupo lidocaína-dexmedetomidina (GLD), tratado com lidocaína (3,0mg/kg) associada à dexmedetomidina (2µg/kg), pela via epidural. Durante a OSH, a infusão de propofol foi aumentada ou reduzida, objetivando-se manutenção de plano anestésico cirúrgico. Foram avaliados os parâmetros: f, FC, SPO2, EtCO2, PAS, PAD, PAM, T°C, nos períodos pré (M1) e transoperatórios (M2 a M7); a taxa mínima de propofol necessária; o tempo de recuperação anestésica e a qualidade da analgesia pós-cirúrgica durante seis horas. Ambos os tratamentos garantiram baixas taxas mínimas de infusão de propofol, todavia o uso da dexmedetomidina resultou em bradicardia inicial, elevação da pressão arterial, maior tempo de recuperação e menor qualidade analgésica, quando comparada ao tramadol.(AU)

The aim of this study was to compare the physiological and analgesic effects and the minimum infusion rate of propofol of epidural anesthesia with lidocaine associated to tramadol or dexmedetomidine, in cats undergoing ovariosalpingohysterectomy (OSH). For this purpose, 16 healthy cats were pretreated with acepromazine (0.08mg kg -1 IM) and propofol was used for induction (dose-effect) and maintenance of anesthesia. After induction, the cats were assigned in two randomized groups (n= 8), named: Lidocaine-tramadol group (LTG), treated with lidocaine (3mg kg -1 ) associated to tramadol (2mg kg -1 ) and Lidocaine-dexmedetomidine group (LDG), treated with lidocaine (3mg kg -1 ) associated to dexmedetomidine (2g kg -1 ), by epidural route. During OSH, propofol infusion was increased or decreased, setting to maintain surgical anesthetic depth. The parameters f, HR, SPO 2 , EtCO 2 , SAP, DAP, MAP, T°C in the pre (M1) and trans-operative periods (M2 to M7); minimum infusion rate of propofol; time of anesthetic recovery and quality of postoperative analgesia during six-hour interval, were evaluated. Both protocols provided low minimum infusion rate of propofol. However, dexmedetomidine resulted in initial bradycardia, elevated blood pressure, longer recovery time, and lower analgesic quality when compared to tramadol.(AU)

Characterisation of the in vivo interactions between detomidine and methadone in horses: Pharmacokinetic and pharmacodynamic modelling.

BACKGROUND: Pharmacokinetic (PK)/pharmacodynamic (PD) modelling offers new insights to design protocols for sedation and analgesia in standing horses. OBJECTIVES: To evaluate the parameters and interactions between detomidine and methadone when given alone or combined in standing horses. STUDY DESIGN: Randomised, placebo-controlled, blinded, crossover. METHODS: Eight adult healthy horses were given six treatments intravenously: saline (SAL); detomidine (5 µg/kg bwt; DET); methadone (0.2 mg/kg bwt; MET) alone or combined with detomidine (2.5 [MLD], 5 [MMD] or 10 [MHD] µg/kg bwt). Venous blood samples were obtained at predetermined times between 0 and 360 min after drug administration. Plasma detomidine and methadone were measured using a single, liquid/liquid extraction technique by liquid chromatography coupled with a triple quadrupole mass spectrometer (LC-MS/MS). Sequential PK/PD modelling compared rival models, with and without PK and PD interaction between drugs, to fit the PD data including height of the head above the ground (HHAG), a visual analogue scale for sedation (VAS), electrical (ET), thermal (TT) and mechanical (MT) nociceptive thresholds and gastrointestinal motility (GIM) [1]. RESULTS: Two and three compartment models best described the PK of detomidine and methadone, respectively. Detomidine decreased its own clearance as well as the clearance of methadone. The interaction of methadone on the effect of detomidine revealed an infra-additive (partial antagonism) effect for HHAG (α = -1.33), VAS (α = -0.98) and GIM (α = -1.05), a positive potentiation for ET (pot = 0.0041) and TT (pot = 0.133) and a synergistic to additive effect for MT (α = 0.78). MAIN LIMITATIONS: This is a small experimental study. CONCLUSIONS: Different PK/PD interactions were demonstrated for each PD parameter and could be modelled in vivo. The modelling of our data will allow us to simulate and predict the effect of constant rate infusions of both drugs for future investigations.

Does dexmedetomidine prevent colistin nephrotoxicity? / Dexmedetomidina impede a nefrotoxicidade da colistina?

Abstract Background In this study, we aimed to investigate the effect of dexmedetomidine on colistin nephrotoxicity in rats. Methods Thirty-two Wistar albino rats were allocated into four groups. Intraperitoneal (ip) saline at 1 mL.kg-1 was administered to the control group and 10 mg.kg-1 ip colistin was given to the colistin group. In the DEX10 group 10 mcg.kg-1 dexmedetomidine ip was given 20 min before the injection of 10 mg.kg-1 ip colistin. In the DEX20 group ip 20 mcg.kg-1 dexmedetomidine was injected 20 min before the administration of 10 mg.kg-1 ip colistin. These treatments were continued twice a day for seven days. Samples were taken on the eighth day. BUN, Cr, KIM-1, TAS, and TOS were examined in blood samples and caspase-3 was examined in kidney tissue samples. Results The values for BUN, Cr and TOS were significantly higher in the colistin group than in the control group. BUN, Cr and TOS changes in the DEX10 and DEX20 groups were not significant compared with the control group but they were significantly lower compared with the colistin group. TAS values in the DEX10 group were significantly lower than in the control group. Apoptotic activity was significantly higher in the colistin group compared with the control group, but there was no significant difference in terms of caspase-3 staining activity when DEX10 and DEX20 groups were compared with the control group. Conclusion Oxidative damage and apoptosis played roles in colistin nephrotoxicity, and colistin nephrotoxicity could be prevented by treatment with dexmedetomidine.

Resumo Justificativa Neste estudo, buscamos investigar o efeito da dexmedetomidina sobre a nefrotoxicidade da colistina em ratos. Métodos Trinta e dois ratos Wistar albinos foram alocados em quatro grupos: o grupo controle recebeu 1 mL.kg-1 de solução salina intraperitoneal (ip); o grupo colistina recebeu 10 mg.kg-1 de colistina ip; o grupo DEX10 recebeu 10 mcg.kg-1 de dexmedetomidina ip 20 minutos antes da injeção de 10 mg.kg-1 de colistina ip; o grupo DEX20 recebeu 20 mcg.kg-1 de dexmedetomidina ip 20 minutos antes da administração de 10 mg.kg-1 de colistina ip. Estes tratamentos foram continuados duas vezes ao dia durante sete dias. As amostras foram colhidas no oitavo dia. BUN, Cr, KIM-1, TAS e TOS foram examinados nas amostras de sangue e caspase-3 foi examinada nas amostras de tecido renal. Resultados Os valores de BUN, Cr e TOS foram significativamente maiores no grupo colistina do que no grupo controle. As alterações em BUN, Cr e TOS nos grupos DEX10 e DEX20 não foram significativas em comparação com o grupo controle, mas foram significativamente menores em comparação com o grupo colistina. Os valores de TAS no grupo DEX10 foram significativamente menores do que no grupo controle. A atividade apoptótica foi significativamente maior no grupo colistina em comparação com o grupo controle, mas não houve diferença significativa em termos de atividade na coloração da caspase-3 quando os grupos DEX10 e DEX20 foram comparados com o grupo controle. Conclusão O dano oxidativo e a apoptose desempenharam papéis na nefrotoxicidade da colistina e a nefrotoxicidade de colistina pode ser prevenida pelo tratamento com dexmedetomidina.

[Does dexmedetomidine prevent colistin nephrotoxicity?] / Dexmedetomidina impede a nefrotoxicidade da colistina?

BACKGROUND: In this study, we aimed to investigate the effect of dexmedetomidine on colistin nephrotoxicity in rats. METHODS: Thirty-two Wistar albino rats were allocated into four groups. Intraperitoneal (ip) saline at 1mL.kg-1 was administered to the control group and 10mg.kg-1 ip colistin was given to the colistin group. In the DEX10 group 10mcg.kg-1 dexmedetomidine ip was given 20min before the injection of 10mg.kg-1 ip colistin. In the DEX20 group ip 20mcg.kg-1 dexmedetomidine was injected 20min before the administration of 10mg.kg-1 ip colistin. These treatments were continued twice a day for seven days. Samples were taken on the eighth day. BUN, Cr, KIM-1, TAS, and TOS were examined in blood samples and caspase-3 was examined in kidney tissue samples. RESULTS: The values for BUN, Cr and TOS were significantly higher in the colistin group than in the control group. BUN, Cr and TOS changes in the DEX10 and DEX20 groups were not significant compared with the control group but they were significantly lower compared with the colistin group. TAS values in the DEX10 group were significantly lower than in the control group. Apoptotic activity was significantly higher in the colistin group compared with the control group, but there was no significant difference in terms of caspase-3 staining activity when DEX10 and DEX20 groups were compared with the control group. CONCLUSION: Oxidative damage and apoptosis played roles in colistin nephrotoxicity, and colistin nephrotoxicity could be prevented by treatment with dexmedetomidine.

Effects of dexmedetomidine on pulse pressure variation changes induced by hemorrhage followed by volume replacement in isoflurane-anesthetized dogs.

OBJECTIVES: To evaluate the effects of dexmedetomidine (DEX) on changes in pulse pressure variation (PPV) induced by hemorrhage followed by volume replacement (VR) during isoflurane (ISO) anesthesia. DESIGN: Prospective, randomized, crossover study. SETTING: Research laboratory at a veterinary teaching hospital. ANIMALS: Eight adult dogs. INTERVENTIONS: Anesthesia was maintained with 1.3 times the minimum alveolar concentration (MAC) of ISO alone or ISO with DEX (ISO-DEX, 1.6 µg/kg [bolus], followed by 2 µg/kg/h). Atropine was administered 30 minutes prior to hemorrhage in the ISO-DEX treatment. Ventilation was controlled (tidal volume of 12 mL/kg, positive end-expiratory pressure of 7 cm H2 O, respiratory rate of 16-20/min) under neuromuscular blockade. After recording baseline data, progressive withdrawal of 10%, 20%, and 30% of blood volume (HV10 , HV20 , and HV30 , respectively [measurements during hemorrhage, indicating x% of blood volume removed]) was followed by VR with autologous blood. MEASUREMENTS AND MAIN RESULTS: In 4 of 8 ISO dogs, hemorrhage decreased mean arterial pressure (MAP) < 60 mm Hg. Based on mean arterial pressure after hemorrhage, dogs were assigned to hypotensive (HG) and normotensive (NG) groups post hoc. During ISO, stroke index and cardiac index decreased with hemorrhage (P < 0.05), while VR normalized or increased these variables. The PPV (%, mean [range]) was increased by hemorrhage from 7 (5-9) to 20 (12-27) and 27 (17-40) at HV20 and HV30 , respectively, only in ISO dogs in the HG; PPV returned to baseline after VR. Dexmedetomidine caused increases in systemic vascular resistance (in dogs in HG and NG), and prevented the increase in PPV with hemorrhage. CONCLUSIONS: During ISO anesthesia, PPV increases in individuals prone to developing hypotension from hypovolemia. Because DEX prevents the increase in PPV associated with hypovolemia, PPV should not be used to guide VR in dogs that have been given DEX.

Associação dexmedetomidina, midazolan e petidina na neuroleptoanagesiade gato-do-mato pequeno (Leopardus tigrinus,Schreder, 1775) / Association dexmedetomidine, midazolam and pethidine in neuroleptoanagesia of Oncilla (Leopardustigrinus, Schreder, 1775)

A contenção química de felídeos silvestres representa um desafio ao anestesista devido a preocupaçãonão só com a segurança do paciente como também com a da equipe envolvida. Neste sentido objetivou-seavaliar a neuroleptoanalgesia em gato-do-mato pequeno com a associação dexmedetomidina, midazolan epetidina. Para tanto utilizou-se seis animais nos quais foram avaliados: a qualidade do relaxamento muscular,da analgesia e da contenção; o período de latência (PL); período hábil (PH); período de recuperação(PR); frequência cardíaca (FC); frequência respiratória (FR); pressão arterial sistólica (PAS) e temperaturaretal (TR). O PL médio foi de 4 minutos, o PH médio foi de 63,75 ± 6,49 minutos e apenas 2 animais apresentaramPR de 48 e 55min respectivamente, os demais recuperaram-se subitamente. A FR foi o parâmetro quemais declinou, embora sua variação assim como a dos demais tenha se mantido dentro de limites segurospara a espécie. A qualidade da analgesia foi classificada como boa já o relaxamento muscular e a contençãofarmacológica como excelentes. O protocolo avaliado apresenta-se como uma alternativa para a contençãofarmacológica de gato-do-mato pequeno em procedimentos de até 40 minutos.(AU)

The chemical restraint of the wild felids its a challenge to the anesthetist due to concern not only with thesafety to the patient, but also with the team. Thus aimed to evaluate the neuroleptoanalgesia in oncilla withdexmedetomidine, midazolam and pethidine associated. For this purpose we used six animals which wereassessed: the quality of the muscle relaxation, analgesia and contention, the latency period (LP); reasonable period (RP); recovery period (ReP); heart rate (HR); respiratory rate (RR); systolic arterial pressure (SAP)and rectal temperature (RT). The average LP was 4 minutes, the RP was 63,75 minutes and only 2 animalshad ReP of 48 and 55 minutes respectively, the others suddenly recovery. The RR was a parameter of majordecline, although it variation (as well as the others) occurred in safe limits for oncilla. The quality of theanalgesia was assessed as good, muscle relaxation and restraint as excellent. The protocol evaluated is presentedas an alternative to pharmacological restraint of oncilla in procedures up to 40 minutes.(AU)

Associação dexmedetomidina, midazolan e petidina na neuroleptoanagesiade gato-do-mato pequeno (Leopardus tigrinus,Schreder, 1775) / Association dexmedetomidine, midazolam and pethidine in neuroleptoanagesia of Oncilla (Leopardustigrinus, Schreder, 1775)

A contenção química de felídeos silvestres representa um desafio ao anestesista devido a preocupaçãonão só com a segurança do paciente como também com a da equipe envolvida. Neste sentido objetivou-seavaliar a neuroleptoanalgesia em gato-do-mato pequeno com a associação dexmedetomidina, midazolan epetidina. Para tanto utilizou-se seis animais nos quais foram avaliados: a qualidade do relaxamento muscular,da analgesia e da contenção; o período de latência (PL); período hábil (PH); período de recuperação(PR); frequência cardíaca (FC); frequência respiratória (FR); pressão arterial sistólica (PAS) e temperaturaretal (TR). O PL médio foi de 4 minutos, o PH médio foi de 63,75 ± 6,49 minutos e apenas 2 animais apresentaramPR de 48 e 55min respectivamente, os demais recuperaram-se subitamente. A FR foi o parâmetro quemais declinou, embora sua variação assim como a dos demais tenha se mantido dentro de limites segurospara a espécie. A qualidade da analgesia foi classificada como boa já o relaxamento muscular e a contençãofarmacológica como excelentes. O protocolo avaliado apresenta-se como uma alternativa para a contençãofarmacológica de gato-do-mato pequeno em procedimentos de até 40 minutos.

The chemical restraint of the wild felids it’s a challenge to the anesthetist due to concern not only with thesafety to the patient, but also with the team. Thus aimed to evaluate the neuroleptoanalgesia in oncilla withdexmedetomidine, midazolam and pethidine associated. For this purpose we used six animals which wereassessed: the quality of the muscle relaxation, analgesia and contention, the latency period (LP); reasonable period (RP); recovery period (ReP); heart rate (HR); respiratory rate (RR); systolic arterial pressure (SAP)and rectal temperature (RT). The average LP was 4 minutes, the RP was 63,75 minutes and only 2 animalshad ReP of 48 and 55 minutes respectively, the others suddenly recovery. The RR was a parameter of majordecline, although it variation (as well as the others) occurred in safe limits for oncilla. The quality of theanalgesia was assessed as good, muscle relaxation and restraint as excellent. The protocol evaluated is presentedas an alternative to pharmacological restraint of oncilla in procedures up to 40 minutes.

Effects of detomidine constant rate infusion on blood glucose and lactate in devoflurane anesthetized horses

Background: The drugs that promote sedation, analgesia, and anesthesia, as inhalatory agents, phenothiazines, benzodiazepines, alpha-2 adrenergic agonists, and opioids, can promote different kinds of side effects. The concept of a balanced anesthesia in equine was developed in order to minimize adverse effects inherent to anesthesia, creating a combination of lower doses of these drugs in comparison with the doses of each one used alone. Alpha-2-adrenoceptor agonists such as xylazine, detomidine, and others, are drugs used for standing sedation, analgesia, and reduction of volatile anesthetic requirement in the equine as well as an agent used to maintenance of arterial blood pressure during anesthesia. Alpha-2 agonists works stimulating receptors of autonomic neurons inducing reduction of heart rate, cardiac output and vascular resistance, hypertension, behavioral changes, and inhibition of insulin secretion. This reduction in insulin levels increases blood glucose concentration in horses due to its lower utilization in insulin-dependent tissues, as muscular and adipose tissues. Muscular tissue is capable to maintain a constant lactate production even in a well oxygenated environment in order to maintain its cellular activity, especially in cases when glucose is not available. To evaluate the effect on blood glucose and lactate, horses were submitted to one hour of detomidine constant rate infusion during sevoflurane inhalatory anesthesia with controlled ventilation, in order to assess blood concentration of glucose and lactate. Materials, Methods & Results: Four adult horses were studied. Detomidine 20 µg.kg-¹ was used as premedication followed by an association of ketamine and diazepam intravenously as anesthetic induction. After intubation, sevoflurane was vaporized at approximately 2.3 V%. Mechanical ventilation was established. After stabilization, an intravenous continuous rate infusion (CRI) of detomidine 5 µg.kg.h-¹ was started. Venous blood samples were collected before premedication, prior to detomidine continuous infusion, 20, 40, and 60 min after beginning of infusion, in order to determination of glucose and lactate serum concentrations. After 60 min of detomidine infusion, the horses were allowed to recovery. There was statistical significant hyperglycemia in the horses under CRI of detomidine. There was no significant increase in blood lactate, despite of the hyperlactatemia in some animals. Discussion: Detomidine CRI of 5 µg.kg.h-¹ does increase blood glucose levels over normal values but not to levels that could be toxic to tissues, mainly CNS. With low levels of serum insulin, body tissues, mainly muscular and adipose tissues, are unable to capture this available blood glucose and these cells depend on lactate metabolism. The lactate serum concentrations below normal range observed in studied horses suggest that all lactate produced by the tissues is being utilized in the energetic metabolism. In according to many authors, lactate is produced and utilized for mitochondrias as energetic source even in fully oxygenated tissues, which seems to be what happened in this experiment. The present study helps to understand energetic metabolism in horses under general inhaled anesthesia with detomidine CRI, a selective alpha-2-adrenoceptor agonist. In order to better evaluate energetic metabolism during inhaled anesthesia under detomidine influence, other studies are suggested, as prolonged anesthesia duration to evaluate a longer adrenergic stimulus induced by detomidine. Besides, other investigations with detomidine CRI in horses submitted to surgical procedures could provide different responses in energetic metabolism.

Effects of detomidine constant rate infusion on blood glucose and lactate in sevofl urane anesthetized horses / Effects of detomidine constant rate infusion on blood glucose and lactate in sevoflurane anesthetized horses

Background: The drugs that promote sedation, analgesia, and anesthesia, as inhalatory agents, phenothiazines, benzodiazepines, alpha-2 adrenergic agonists, and opioids, can promote different kinds of side effects. The concept of a balanced anesthesia in equine was developed in order to minimize adverse effects inherent to anesthesia, creating a combination of lower doses of these drugs in comparison with the doses of each one used alone. Alpha-2-adrenoceptor agonists such as xylazine, detomidine, and others, are drugs used for standing sedation, analgesia, and reduction of volatile anesthetic requirement in the equine as well as an agent used to maintenance of arterial blood pressure during anesthesia. Alpha-2 agonists works stimulating receptors of autonomic neurons inducing reduction of heart rate, cardiac output and vascular resistance, hypertension, behavioral changes, and inhibition of insulin secretion. This reduction in insulin levels increases blood glucose concentration in horses due to its lower utilization in insulin-dependent tissues, as muscular and adipose tissues. Muscular tissue is capable to maintain a constant lactate production even in a well oxygenated environment in order to maintain its cellular activity, especially in cases when glucose is not available. To evaluate the effect on blood glucose and lactate, horses were submitted to one hour of detomidine c

Background: The drugs that promote sedation, analgesia, and anesthesia, as inhalatory agents, phenothiazines, benzodiazepines, alpha-2 adrenergic agonists, and opioids, can promote different kinds of side effects. The concept of a balanced anesthesia in equine was developed in order to minimize adverse effects inherent to anesthesia, creating a combination of lower doses of these drugs in comparison with the doses of each one used alone. Alpha-2-adrenoceptor agonists such as xylazine, detomidine, and others, are drugs used for standing sedation, analgesia, and reduction of volatile anesthetic requirement in the equine as well as an agent used to maintenance of arterial blood pressure during anesthesia. Alpha-2 agonists works stimulating receptors of autonomic neurons inducing reduction of heart rate, cardiac output and vascular resistance, hypertension, behavioral changes, and inhibition of insulin secretion. This reduction in insulin levels increases blood glucose concentration in horses due to its lower utilization in insulin-dependent tissues, as muscular and adipose tissues. Muscular tissue is capable to maintain a constant lactate production even in a well oxygenated environment in order to maintain its cellular activity, especially in cases when glucose is not available. To evaluate the effect on blood glucose and lactate, horses were submitted to one hour of detomidine c

Effects of detomidine constant rate infusion on blood glucose and lactate in sevofl urane anesthetized horses / Effects of detomidine constant rate infusion on blood glucose and lactate in sevoflurane anesthetized horses

Background: The drugs that promote sedation, analgesia, and anesthesia, as inhalatory agents, phenothiazines, benzodiazepines, alpha-2 adrenergic agonists, and opioids, can promote different kinds of side effects. The concept of a balanced anesthesia in equine was developed in order to minimize adverse effects inherent to anesthesia, creating a combination of lower doses of these drugs in comparison with the doses of each one used alone. Alpha-2-adrenoceptor agonists such as xylazine, detomidine, and others, are drugs used for standing sedation, analgesia, and reduction of volatile anesthetic requirement in the equine as well as an agent used to maintenance of arterial blood pressure during anesthesia. Alpha-2 agonists works stimulating receptors of autonomic neurons inducing reduction of heart rate, cardiac output and vascular resistance, hypertension, behavioral changes, and inhibition of insulin secretion. This reduction in insulin levels increases blood glucose concentration in horses due to its lower utilization in insulin-dependent tissues, as muscular and adipose tissues. Muscular tissue is capable to maintain a constant lactate production even in a well oxygenated environment in order to maintain its cellular activity, especially in cases when glucose is not available. To evaluate the effect on blood glucose and lactate, horses were submitted to one hour of detomidine c

Background: The drugs that promote sedation, analgesia, and anesthesia, as inhalatory agents, phenothiazines, benzodiazepines, alpha-2 adrenergic agonists, and opioids, can promote different kinds of side effects. The concept of a balanced anesthesia in equine was developed in order to minimize adverse effects inherent to anesthesia, creating a combination of lower doses of these drugs in comparison with the doses of each one used alone. Alpha-2-adrenoceptor agonists such as xylazine, detomidine, and others, are drugs used for standing sedation, analgesia, and reduction of volatile anesthetic requirement in the equine as well as an agent used to maintenance of arterial blood pressure during anesthesia. Alpha-2 agonists works stimulating receptors of autonomic neurons inducing reduction of heart rate, cardiac output and vascular resistance, hypertension, behavioral changes, and inhibition of insulin secretion. This reduction in insulin levels increases blood glucose concentration in horses due to its lower utilization in insulin-dependent tissues, as muscular and adipose tissues. Muscular tissue is capable to maintain a constant lactate production even in a well oxygenated environment in order to maintain its cellular activity, especially in cases when glucose is not available. To evaluate the effect on blood glucose and lactate, horses were submitted to one hour of detomidine c

Analgesia em procedimentos cirúrgicos de abdômen superior com bloqueio interpleural / Analgesia in upper abdominal surgery with interpleural block

JUSTIFICATIVA E OBJETIVOS: Pesquisas empregando bloqueio interpleural com anestésico local, opioide e agonista Alfa2-adrenérgico ou bloqueador do receptor N-metil-D-aspartato (NMDA), observaram a ocorrência de analgesia pós-operatória em cirurgias de abdômen superior. O objetivo deste estudo foi observar a presença de dor no pós-operatório de cirurgias de colecistectomia por via subcostal.MÉTODO: Após aprovação pelo Comitê de Ética, participaram do experimento aleatório e prospectivo, 40 pacientes, de ambos os sexos, com idade variando de 18 a 50 anos, peso entre 50 e 100 kg, estado físico ASA I e II, submetidos à colecistectomia por via subcostal, sob anestesia geral associada ao bloqueio interpleural. Foram administradas levobupivacaína a 0,5% (100 mg) com adrenalina 1:200.000 (5 µg.mL-1) ou ropivacaína a 0,75% (150 mg), morfina (3 mg) e clonidina (3 µg.kg-1) ou cetamina (0,5 mg.kg-1), ao nível EIC7, na linha axilar média, com agulha de Tuohy 17G, por via interpleural. A indução da anestesia geral foi realizada com a injeção de etomidato (0,2 mg.kg-1), alfentanil (30 µg.kg-1) e rocurônio (0,6 mg.kg-1) e a manutenção com oxigênio e isoflurano (0,5 vol% a 3,0 vol%). A analgesia pós-operatória, analisada pela escala analógica visual (EAV), foi observada às 6h, 12h, 18h e 24h após o término do ato operatório.RESULTADOS: Apresentaram dor pós-operatória: grupo RMC (ropivacaína, morfina e clonidina), um até 6h, seis entre 6 e 12h e um entre 18 e 24h; grupo RMK (ropivacaína, morfina e cetamina), quatro até 6h, quatro entre 6 e 12h, um entre 12 e 18h e um entre 18 e 24h; grupo LMC (levobupivacaína, morfina e clonidina), quatro até 6h e quatro entre 6 e 12h; grupo LMK (levobupivacaína, morfina e cetamina, cinco até 6h, quatro entre 6 e 12h e um entre 12 e 18h. Aplicando o teste Exato de Fisher observou-se diferença estatística significante entre o tempo de observação até 6h e os demais no grupo RMC; entre o tempo de observação até 6h e os 12-18h e 18-24h nos grupos RMK e LMK. Não ocorreram complicações relacionadas ao bloqueio interpleural.CONCLUSÃO: A necessidade de associar opioide ao analgésico comum para abolir a dor, em cirurgias de colecistectomia por via subcostal, ocorreu em número reduzido de pacientes.

BACKGROUND AND OBJECTIVES: Researches using interpleural block with local anesthetics, opioid and alpha2-adrenergic agonist or N-Methyl-D-aspartate (NMDA) receptor blocker have shown the presence of postoperative analgesia in upper abdominal surgeries. This study aimed at observing the presence of pain in the postoperative period of subcostal cholecystectomies. METHOD: After The Ethics Committee approval, participated in this randomized, prospective study 40 patients of both genders, aged 18 to 50 years, weighing between 50 and 100 kg, physical status ASA I and II, submitted to subcostal cholecystectomy under general anesthesia associated to interpleural block. The following drugs were administered: 0.5% levobupivacaine (100 mg) with 1:200.000 epinephrine (5 µg.mL-1) or 0.75% ropivacaine (150 mg), morphine (3 mg) and clonidine (3 µg.kg-1) or ketamine (0,5 mg.kg-1), at EIC7, in the medium axillary line with 17G Tuohy needle by interpleural route. General anesthesia was induced with etomidate (0.2 mg.kg-1), alfentanil (30 µg.kg-1) and rocuronium (0.6 mg.kg-1) and was maintained with oxygen and isoflurane (0.5 vol% at 3.0 vol%). Postoperative analgesia, evaluated by the visual analog scale (VAS), was observed at 6h, 12h, 18h and 24h after surgery completion.RESULTS: Postoperative pain was observed: one patient up to 6h, six between 6 and 12h and one between 18 and 24h in the RMC group (ropivacaine, morphine and clonidine); four patients up to 6h, four between 6 and 12h, one between 12 and 18h and one between 18 and 24h in the RMK group (ropivacaine, morphine and ketamine); four patients up to 6h, and four between 6 and 12h in the LMC group (levobupivacaine, morphine and clonidine); five patients up to 6h, four between 6 and 12h, and one between 12 and 18h in the LMK group (levobupivacaine, morphine and ketamine). Fisher's Exact test has shown statistically significant difference between 6h observation time and the others in the RMC group; between 6h observation time and 12-18h and 18-24h in RMK and LMK groups. There were no interpleural block-related complications.CONCLUSION: Only a small number of patients needed the association of opioid to normal analgesics to abolish pain in subcostal cholecystectomy surgeries.

Cardiovascular assessment in horses sedated with xylazine or amitraz / Avaliação cardiovascular em eqüinos sedados com xilazina ou amitraz

Cardiovascular effects due to intravenous (IV) xylazine (1.0mg/kg) or amitraz (0.1 or 0.4mg/kg) were evaluated in horses. Left ventricular function indexes, heart rate (HR), and cardiac output (CO) were measured by echocardiography. Second degree atrioventricular (AV) block was detected by electrocardiography. Invasive arterial blood pressure (AP) was also evaluated. All parameters were measured immediately before and during 60 minutes after drug injection. HR, CO, and second degree AV block were different between xylazine and amitraz-0.4mg/kg groups. Xylazine induced initial hypertension 10 minutes after injection, and hypotension was observed 30 minutes after amitraz-0.4mg/kg administration. Except for the second degree AV block which occurred only at five minutes, there was no change in the echocardiographic measurements after administration of amitraz-0.1mg/kg. Thus, amitraz-0.4mg/kg and xylazine (1.0mg/kg) induced similar cardiovascular side effects, but long-lasting action of amitraz-0.4mg/kg in the cardiovascular system was observed.(AU)

Avaliaram-se efeitos cardiovasculares decorrentes da administração intravenosa (IV) de xilazina (1,0mg/kg) ou amitraz (0,1 ou 0,4mg/kg) em cavalos. Os índices ventriculares, a freqüência cardíaca (FC) e o débito cardíaco (DC) foram mensurados por ecocardiografia, e o bloqueio atrioventricular de segundo grau (BAV2), detectado por eletrocardiografia. A pressão arterial invasiva foi também avaliada. Todos os parâmetros foram mensurados imediatamente antes e durante 60 minutos após a administração dos fármacos. Os valores da FC, do DC e do BAV2 apresentaram alterações significativas nos grupos da xilazina e do amitraz na dose de 0,4mg/kg. A xilazina induziu hipertensão inicial 10 minutos após sua administração e a dose de 0,4mg/kg amitraz induziu hipotensão após 30 minutos. Exceto pela ocorrência de BAV2 aos cinco minutos, não houve alteração nas mensurações ecocardiográficas após a administração de amitraz-0.1mg/kg. Nas doses utilizadas, a xilazina (1,0mg/kg) e o amitraz-0,4mg/kg promoveram alterações semelhantes no sistema cardiovascular, porém os efeitos cardiovasculares provocados pelo amitraz foram mais prolongados.(AU)

Cardiovascular assessment in horses sedated with xylazine or amitraz / Avaliação cardiovascular em eqüinos sedados com xilazina ou amitraz

Cardiovascular effects due to intravenous (IV) xylazine (1.0mg/kg) or amitraz (0.1 or 0.4mg/kg) were evaluated in horses. Left ventricular function indexes, heart rate (HR), and cardiac output (CO) were measured by echocardiography. Second degree atrioventricular (AV) block was detected by electrocardiography. Invasive arterial blood pressure (AP) was also evaluated. All parameters were measured immediately before and during 60 minutes after drug injection. HR, CO, and second degree AV block were different between xylazine and amitraz-0.4mg/kg groups. Xylazine induced initial hypertension 10 minutes after injection, and hypotension was observed 30 minutes after amitraz-0.4mg/kg administration. Except for the second degree AV block which occurred only at five minutes, there was no change in the echocardiographic measurements after administration of amitraz-0.1mg/kg. Thus, amitraz-0.4mg/kg and xylazine (1.0mg/kg) induced similar cardiovascular side effects, but long-lasting action of amitraz-0.4mg/kg in the cardiovascular system was observed.

Avaliaram-se efeitos cardiovasculares decorrentes da administração intravenosa (IV) de xilazina (1,0mg/kg) ou amitraz (0,1 ou 0,4mg/kg) em cavalos. Os índices ventriculares, a freqüência cardíaca (FC) e o débito cardíaco (DC) foram mensurados por ecocardiografia, e o bloqueio atrioventricular de segundo grau (BAV2), detectado por eletrocardiografia. A pressão arterial invasiva foi também avaliada. Todos os parâmetros foram mensurados imediatamente antes e durante 60 minutos após a administração dos fármacos. Os valores da FC, do DC e do BAV2 apresentaram alterações significativas nos grupos da xilazina e do amitraz na dose de 0,4mg/kg. A xilazina induziu hipertensão inicial 10 minutos após sua administração e a dose de 0,4mg/kg amitraz induziu hipotensão após 30 minutos. Exceto pela ocorrência de BAV2 aos cinco minutos, não houve alteração nas mensurações ecocardiográficas após a administração de amitraz-0.1mg/kg. Nas doses utilizadas, a xilazina (1,0mg/kg) e o amitraz-0,4mg/kg promoveram alterações semelhantes no sistema cardiovascular, porém os efeitos cardiovasculares provocados pelo amitraz foram mais prolongados.

Efeitos sedativos das associações xilazina/midazolam e medetomidina/midazolan no gato (Felis catus) / Sedative effects of xylazine/midazolam and medetomidine/midazolam in cats

Vinte gatos, machos, sem raça definida, com 1 a 2 anos de idade, hígidos, foram divididos em dois grupos iguais. Em ambos os grupos utilizou-se como medicação pré-anestésica o sulfato de atropina, na dose de 0,03 mg/k, por via intramuscular, 20 minutos antes da administração da associação dos alfa-2 agonistas e do midazolam. O primeiro grupo (x/m) foi submetido à administração intramuscular da associação xilazinal midazolam, nas doses de 1 mg/kg e 0,2 mg/kg e o segundo grupo (m/m) à associação medetomidinal midazolam, nas doses de 0,08 mg/kg, e 0,2 mg/kg, respectivamente. A administração simultânea de alfa-2 agonistas e midazolam induziu a uma rápida e profunda depressão do SNC, que foi mais rápida com a combinação medetomidina/midazolam. O efeito sedativo máximo ocorreu entre 20-30 min. com ambas as combinações. A recuperação foi tranquila sem alterações expressivas.

Twenty healthy tom cats, from 1 to 2 years of age and weighting between 3,5 and 5 kg were used in the study. The animais were divided into two groups and were premedicated with 0,03mg/kg of atropine sulfate i.m. 20 min prior to the administration of 1 mg/kg xykazine and 0,2 mg/kg midazolam (group m/m - n = 1 O) i.m .. The combination of alfa2 agonists and midazolam induced a rapid CNS depression. The onset of sedation was earlier with m/m than x/m. The maximal sedative effect occurred at 20 to 30 min with the two combinations and recovery was uneventful.