Sedation with dexmedetomidine-butorphanol or xylazine-butorphanol continuous intravenous infusions during unilateral ovariectomy in standing donkeys.

BACKGROUND: Intravenous infusions of alpha-2 adrenoceptor sedatives and opioids can potentially facilitate surgery in donkeys while standing. Literature on this subject matter is scant. OBJECTIVES: Evaluation of efficacy of sedation from α2-adrenoceptors (dexmedetomidine or xylazine) and butorphanol during ovariectomy in standing donkeys. STUDY DESIGN: Randomised, masked in vivo experiment. METHODS: Thirteen female donkeys were sedated with butorphanol (0.05 mg/kg bwt followed by 0.05 mg/kg bwt/h) IV. Concomitantly, 6 of the 13 jennies were sedated with dexmedetomidine 2.5 mcg/kg bwt followed by 2.5 mcg/kg bwt/h (Dex-B group), while seven jennies were sedated with xylazine 0.5 mg/kg bwt followed by 0.5 mg/kg bwt/h (Xyl-B group). A line block of the left flank and an infiltration block around uterine ligament were performed with lidocaine. While the jennies underwent ovariectomies standing, sedation scores and head height above ground were assessed at 2 and 10 min after sedative boluses and every 10 min thereafter. If sedation was too light or too deep, the dose of dexmedetomidine or xylazine was increased or decreased by 25% of the original infusion rate, while butorphanol infusion rate was constant. Physiological parameters were measured. Normally distributed data were compared using the two-sample t test while repeatedly measured data were tested for differences between and within groups using repeated measures analysis of variance (ANOVA) by ranks followed by a Wilcoxon test with Tukey Honest Significant Difference for multiple testing. Statistical significance was set at p < 0.05. RESULTS: Both Dex-B and Xyl-B caused moderate to marked sedation adequate for ovariectomy in donkeys. Evident sedation was absent by 60 min of termination of infusions. No adverse physiological effects were observed. MAIN LIMITATIONS: Study on ovariectomy cases only, no pharmacokinetic profiling. CONCLUSIONS: Dexmedetomidine or xylazine and butorphanol sedation is feasible for ovariectomy in standing donkeys.

Morphine in donkeys: Antinociceptive effect and preliminary pharmacokinetics.

BACKGROUND: Morphine is the prototypical µ-opioid receptor agonist used to provide analgesia in veterinary species. Its effects are well-described in horses but not donkeys. OBJECTIVES: To determine the antinociceptive effects of two doses of morphine in donkeys. To describe preliminary pharmacokinetic parameters of morphine in donkeys. STUDY DESIGN: In vivo experiment. METHODS: Eight adult castrated male donkeys were given intravenous (IV) 0.9% saline, morphine 0.1 mg/kg bwt (LDM), or morphine 0.5 mg/kg bwt (HDM) in a randomised order with a minimum 1-week washout period. Mechanical nociceptive thresholds (MNTs) were determined by a blinded investigator pre-injection and 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 300, and 360 min post-injection. Venous blood samples were collected pre-injection and 2, 5, 10, 15, 30, 45, 60, 90, and 120 min post-injection. Data were analysed using Friedman's test with Dunn's post hoc test for multiple comparisons. Pharmacokinetic parameters were calculated for the HDM treatment. RESULTS: Baseline MNT was [median (interquartile range)] 8.9 (7.1-10.3) N and did not differ between treatments. Peak MNTs occurred at 60 min for both LDM (16.2 N) and HDM (25.0 N) treatments. MNTs after HDM treatment were higher than saline (p < 0.04) at 15, 60, 90, 120, 150, 180, 240, and 300 min post-injection. MNTs after LDM treatment were higher than baseline (p < 0.05) at 45 and 60 min post-injection. Terminal half-life for HDM was (mean ± SD) 51.0 ± 10.7 min, the volume of distribution at steady-state 2.07 ± 0.33 L/min and clearance 49.2 ± 4.16 ml * min/kg using noncompartmental analysis. The concentration of morphine-3-glucuronide (M3G) was higher than morphine-6-glucuronide (M6G) at all sampled time points. MAIN LIMITATIONS: Short duration of plasma sampling for pharmacokinetic analysis; lack of objective measure of gastrointestinal function. CONCLUSIONS: The HDM treatment provided mechanical antinociception in donkeys with no significant adverse effects.

ISOFLURANE RESPIRATORY ANESTHETIC INDEX IN CHICKENS (GALLUS GALLUS DOMESTICUS).

Respiratory depression from isoflurane seems to be greater in birds than in mammals. Isoflurane respiratory anesthetic index (AI) has only been evaluated in ducks (Anas platyrhynchos), which indeed showed a lower AI compared to mammals, but the isoflurane AI for other avian species is not known. The aim of this study was to evaluate the isoflurane AI in chickens (Gallus gallus domesticus). Six adult hens were anesthetized with isoflurane for determination of the minimum anesthetic concentration (MAC) using the bracketing method. During a second anesthetic event, the isoflurane AI was determined by progressively increasing the expired fraction of isoflurane by 0.5 times MAC until apnea was achieved (ETiso-apnea). The isoflurane AI was considered the ratio between the ETiso-apnea and the MAC. Heart rate, systolic arterial pressure, respiratory rate, and end-tidal carbon dioxide were continuously monitored throughout both anesthetic events. Data were analyzed using a mixed-effect model with Greenhouse-Geisser correction, followed by Tukey's test. The MAC for isoflurane was 1.18% ± 0.09% (mean ± SD). The ETiso-apnea was 3.31% ± 0.34% and the isoflurane AI was 2.80 ± 0.26. In chickens, isoflurane AI is similar to that measured in mammals, which is in contrast with published data in other avian species.

Aplicação intravenosa de metronidazol, ceftriaxona e enrofloxacina em cadelas anestesiadas com isoflurano: repercussão dos parâmetros hemodinâmicos e respiratórios / Intravenous application of metronidazole, ceftriaxone and enrofloxacin in dogs anesthetized with isoflurane: impact of hemodynamic and cardiorespiratory parameters

Background: The prophylactic use of antimicrobials in patients undergoing surgery is widely performed due to its power to reduce and control infections in the surgical site. Metronidazole, ceftriaxone and enrofloxacin are drugs widely used in veterinary medicine, even during anesthesia, either in healthy patients or under critical conditions. Despite several reports on hemodynamic reactions after intravenous application of antimicrobials in dogs, there are few studies on these effects in dogs undergoing anesthesia. The objective of this study was to evaluate the hemodynamic and cardiorespiratory effects of metronidazole, ceftriaxone and enrofloxacin in dogs anesthetized with isoflurane. Materials, Methods & Results: Forty healthy bitches were used, equally divided into four experimental groups of 10 animals each: placebo group (PG), metronidazole group (MG), ceftriaxone group (CG) and enrofloxacin group (EG). After the experimental phase of data collection, all animals were submitted to ovariohysterectomy using the minimally invasive approach. A catheter was placed in the dorsal metatarsal artery for direct blood pressure monitoring, with systolic (SBP), mean (MBP) and diastolic (DBP) blood pressures were continuously monitored by means of a transducer connected to a multiparametric monitor. The others measured data were heart rate (HR), respiratory rate (RR), body temperature (T°C), carbon dioxide expired fraction (ETCO2), oxygen saturation of hemoglobin (SpO2) in T0 (time immediately before performing the treatment), 5 (T5), 10 (T10), 15 (T15), 20 (T20) and 30 (T30) minutes after administration of the antimicrobial. Anesthetic induction was performed with propofol and anesthetic maintenance was performed with isoflurane. After reaching anesthesia with a surgical plan, all parameters were measured before treatments were performed (T0). Then the...

Topical and intradermal delivery of PpIX precursors for photodynamic therapy with intense pulsed light on porcine skin model.

In order to purposely decrease the time of the photodynamic therapy (PDT) sessions, this study evaluated the effects of PDT using topical and intradermal delivery of two protoporphyrin (PpIX) precursors with intense pulsed light (IPL) as irradiation source. This study was performed on porcine skin model, using an IPL commercial device (Intense Pulse Light, HKS801). IPL effect on different administration methods of two PpIX precursors (ALA and MAL) was investigated: a topical cream application and an intradermal application using a needle-free, high-pressure injection system. Fluorescence investigation showed that PpIX distribution by needle-free injection was more homogeneous than that by cream, suggesting that a shorter drug-light interval in PDT protocols is possible. The damage induced by IPL-PDT assessed by histological analysis mostly shows modifications in collagens fibers and inflammation signals, both expected for PDT. This study suggested an alternative protocol for the PDT treatment, possibility half of the incubation time and with just 3 min of irradiation, making the IPL-PDT, even more, promising for the clinical treatment.

Effects of a single intravenous bolus of fentanyl on the minimum anesthetic concentration of isoflurane in chickens (Gallus gallus domesticus).

OBJECTIVE: To assess the temporal effects of a single fentanyl intravenous (IV) bolus on the minimum anesthetic concentration (MAC) of isoflurane in chickens and to evaluate the effects of this combination on heart rate (HR) and rhythm, systemic arterial pressures (sAP) and ventilation. STUDY DESIGN: Prospective experimental trial. ANIMALS: Seventeen adult chickens weighing 1.8±0.2 kg. METHODS: Individual isoflurane MAC for 17 chickens was previously determined using the bracketing method. Chickens were anesthetized with isoflurane to evaluate the effects of a single IV fentanyl bolus (10 or 30 µg kg-1) on isoflurane MAC over time using the up-and-down method. Ventilation was controlled. The isoflurane MAC reduction was estimated by logistic regression at 5 and 15 minutes after fentanyl administration. In the second phase, seven chickens were anesthetized with isoflurane, and fentanyl was administered (30 µg kg-1) IV over 1 minute during spontaneous ventilation and HR and rhythm, sAP and ventilation variables were measured. RESULTS: At 5 minutes after IV administration of fentanyl (10 or 30 µg kg-1), isoflurane MAC was significantly reduced by 17.6% (6.1-29.1%) [logistic regression estimate (95% Wald confidence interval)] and 42.6% (13.3-71.9%), respectively. Isoflurane MAC reduction at 15 minutes after IV administration of fentanyl (10 or 30 µg kg-1) was 6.2% (-0.6 to 12.9%) and 13.2% (-0.9 to 27.3%), respectively; however, this reduction was not significant. No clinically significant cardiopulmonary changes or arrhythmias were detected after the administration of fentanyl (30 µg kg-1). CONCLUSIONS AND CLINICAL RELEVANCE: Administration of a single fentanyl bolus induced a dose-dependent and short-lasting reduction in isoflurane MAC. The higher dose induced no significant cardiopulmonary depression in isoflurane-anesthetized chickens during spontaneous ventilation. In chickens anesthetized with isoflurane, the clinical usefulness of a single fentanyl bolus is limited by its short duration of effect.

Effects of Methadone on the Minimum Anesthetic Concentration of Isoflurane, and Its Effects on Heart Rate, Blood Pressure and Ventilation during Isoflurane Anesthesia in Hens (Gallus gallus domesticus).

The aim of this study was to measure the temporal effects of intramuscular methadone administration on the minimum anesthetic concentration (MAC) of isoflurane in hens, and to evaluate the effects of the isoflurane-methadone combination on heart rate and rhythm, blood pressure and ventilation. Thirteen healthy adult hens weighing 1.7 ± 0.2 kg were used. The MAC of isoflurane was determined in each individual using the bracketing method. Subsequently, the reduction in isoflurane MAC produced by methadone (3 or 6 mg kg(-1), i.m.) was determined by the up-and-down method. Stimulation was applied at 15 and 30 minutes, and at 45 minutes if the bird had not moved at 30 minutes. Isoflurane MAC reduction was calculated at each time point using logistic regression. After a washout period, birds were anesthetized with isoflurane and methadone, 6 mg kg(-1) i.m. was administered. Heart rate and rhythm, respiratory rate, blood gas values and invasive blood pressure were measured at 1.0 and 0.7 isoflurane MAC, and during 45 minutes after administration of methadone once birds were anesthetized with 0.7 isoflurane MAC. Fifteen minutes after administration of 3 mg kg(-1) of methadone, isoflurane MAC was reduced by 2 (-9 to 13)% [logistic regression estimate (95% Wald confidence interval)]. Administration of 6 mg kg(-1) of methadone decreased isoflurane MAC by 29 (11 to 46)%, 27 (-3 to 56)% and 10 (-8 to 28)% after 15, 30 and 45 minutes, respectively. Methadone (6 mg kg(-1)) induced atrioventricular block in three animals and ventricular premature contractions in two. Methadone caused an increase in arterial blood pressure and arterial partial pressure of carbon dioxide, while heart rate and pH decreased. Methadone, 6 mg kg(-1) i.m. significantly reduced isoflurane MAC by 30% in hens 15 minutes after administration. At this dose, methadone caused mild respiratory acidosis and increase in systemic blood pressure.

Assessment of ALA-induced PpIX production in porcine skin pretreated with microneedles.

Photodynamic therapy (PDT) is used for skin treatments of premalignant and cancer lesions and recognized as a non-invasive technique that combines tissue photosensitization and subsequent exposure to light to induce cell death. However, it is limited to the treatment of superficial lesions, mainly due to the low cream penetration. Therefore, the improvement of transdermal distribution of aminolevulinic acid (ALA) is needed. In this study, the kinetics and homogeneity of production of ALA-induced PpIX after the skin pre-treatment with microneedles rollers of 0.5, 1.0 and 1.5 mm length were investigated. An improvement in homogeneity and production of PpIX was shown in a porcine model. Widefield fluorescence imaging three hours after the topical application of ALA-cream in the combined treatment with microeedles rollers.

Hyoscine-N-butylbromide premedication on cardiovascular variables of horses sedated with medetomidine.

OBJECTIVE: To evaluate the effects of intravenous (IV) or intramuscular (IM) hyoscine premedication on physiologic variables following IV administration of medetomidine in horses. STUDY DESIGN: Randomized, crossover experimental study. ANIMALS: Eight healthy crossbred horses weighing 330 ± 39 kg and aged 7 ± 4 years. METHODS: Baseline measurements of heart rate (HR), cardiac index (CI), respiratory rate, systemic vascular resistance (SVR), percentage of patients with second degree atrioventricular (2(o) AV) block, mean arterial pressure (MAP), pH, and arterial partial pressures of carbon dioxide (PaCO2 ) and oxygen (PaO2 ) were obtained 5 minutes before administration of IV hyoscine (0.14 mg kg(-1) ; group HIV), IM hyoscine (0.3 mg kg(-1) ; group HIM), or an equal volume of physiologic saline IV (group C). Five minutes later, medetomidine (7.5 µg kg(-1) ) was administered IV and measurements were recorded at various time points for 130 minutes. RESULTS: Medetomidine induced bradycardia, 2(o) AV blocks and increased SVR immediately after administration, without significant changes in CI or MAP in C. Hyoscine administration induced tachycardia and hypertension, and decreased the percentage of 2(o) AV blocks induced by medetomidine. Peak HR and MAP were higher in HIV than HIM at 88 ± 18 beats minute(-1) and 241 ± 37 mmHg versus 65 ± 16 beats minute(-1) and 192 ± 38 mmHg, respectively. CI was increased significantly in HIV (p ≤ 0.05). Respiratory rate decreased significantly in all groups during the recording period. pH, PaCO2 and PaO2 were not significantly changed by administration of medetomidine with or without hyoscine. CONCLUSION AND CLINICAL RELEVANCE: Hyoscine administered IV or IM before medetomidine in horses resulted in tachycardia and hypertension under the conditions of this study. The significance of these changes, and responses to other dose rates, requires further investigation.

Effects of butorphanol on the minimum anesthetic concentration for sevoflurane in guineafowl (Numida meleagris).

OBJECTIVE: To determine the minimum anesthetic concentration (MAC) for sevoflurane and measure the dose and temporal effects of butorphanol on the MAC for sevoflurane in guineafowl. ANIMALS: 10 healthy adult guineafowl (Numida meleagris). PROCEDURES: Each bird was anesthetized with sevoflurane, and a standard bracketing method was used to measure the MAC in response to a noxious electrical stimulus. Subsequently, conditions were adjusted so that each bird was anesthetized with sevoflurane at a fraction of its respective MAC (eg, 0.7 times the MAC for that bird). Butorphanol tartrate (2 mg/kg, IV) was administered, and a noxious stimulus was applied every 15 minutes until the bird moved in response. The reduction in MAC was estimated with logistic regression by use of a standard quantal method. After an interval of ≥ 1 week, the MAC reduction experiment was repeated with an increased butorphanol dosage (4 mg/kg). RESULTS: Individual mean ± SE MAC for sevoflurane was 2.9 ± 0.1%. At 15 minutes after administration of 2 mg of butorphanol/kg, estimated reduction in the MAC for sevoflurane was 9 ± 3%. At 15 and 30 minutes after administration of 4 mg of butorphanol/kg, estimated reduction in the MAC for sevoflurane was 21 ± 4% and 11 ± 8%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: In guineafowl, the MAC for sevoflurane was similar to values reported for other species. Increasing the butorphanol dosage decreased the MAC for sevoflurane, but the effect was small and of short duration for dosages up to 4 mg/kg.

ECHOCARDIOGRAPHIC ASSESSMENT AFTER INTRAVENOUS AMITRAZ OR XYLAZINE INJECTION IN CATS / AVALIAÇÃO ECOCARDIOGRÁFICA DE GATOS APÓS A ADMINISTRAÇÃO INTRAVENOSA DE AMITRAZ OU XILAZINA

Amitraz acts on a2-adrenergic receptors in a competitive and reversible way, leading to some xylazine-like effects. To evaluate the left ventricular function index after amitraz or xylazine administration, eight mongrel cats were submitted to intravenous injection: group X (xylazine), group A (amitraz) or group D (diluent). The same cats were used in all groups, after a 15-day interval. Heart rate (HR) and rhythm, shortening fraction (%SF), ejection fraction (%EF) and cardiac index (CI) were measured by echocardiography immediately before and during 60 minutes after drug injection. Amitraz and xylazine induced first-degree atrioventricular block (1st AVB) and decreases in HR, %SF, %EF and CI. The mean values of HR and all echocardiographic parameters of group X were significantly lower comparing to group A. It was concluded that both a2-agonists produce bradycardia and 1st AVB, but xylazine causes greater depression of the cardiac contractility.  KEYWORDS: Amitraz, xylazine, echocardiography, electrocardiography, cats

O amitraz age de forma competitiva e reversível em receptores adrenérgicos do tipo a2, desencadeando efeitos similares aos da xilazina. Com o objetivo de avaliar a função ventricular esquerda após a administração de amitraz ou xilazina, oito gatos SRD foram submetidos a injeções intravenosas: grupo X (xilazina), grupo A (amitraz) ou grupo D (diluente). Os mesmos animais foram utilizados em todos os grupos após um intervalo mínimo de quinze dias. Foram avaliados frequência cardíaca (FC), ritmo cardíaco, fração de ejeção (FE), fração de encurtamento (FS) e índice cardíaco (IC), por meio de eletrocardiografia e ecocardiografia, imediatamente antes e durante os primeiros sessenta minutos após a aplicação. Tanto o amitraz quanto a xilazina induziram bloqueio atrioventricular de primeiro grau (1º BAV) e diminuição de FC, FE, FS e IC. As médias da FC e de todos os parâmetros ecocardiográficos do grupo X foram estatisticamente menores do que as do grupo A. Concluiu-se que ambos os agonistas adrenérgicos de receptores tipo a2 causaram bradicardia e 1º BAV; contudo, a xilazina produziu maior depressão na contratilidade cardíaca. PALAVRAS-CHAVES: Amitraz, xilazina, ecocardiografia, eletrocardiografia, gatos.

BEHAVIORAL EVALUATION OF THE ISOFLURANE ANESTHESIA AND XYLAZINE AND MEDETOMIDINE CONTINUOUS INFUSION IN HORSES / AVALIAÇÃO COMPORTAMENTAL DA ANESTESIA POR ISOFLUORANO E INFUSÃO CONTÍNUA DE XILAZINA E MEDETOMIDINA EM EQUINOS

The association of an -2 agonist to an anesthetic protocol leads to deep sedation, muscle relaxation and potent analgesia, reducing the quantity of other anesthetic agents to reach the ideal anesthetic plan to the surgical procedure. This study evaluated comparatively the tranquilization, induction and recovery quality of the isofluorane anesthesia and xylazine and medetomidine continuous infusion in 16 horses. It was possible to conclude that, in this specie, the medetomidine protocol warrants wider muscle relaxation, better quality of anesthetic induction and recovery, even though it presents the same tranquilization quality of the xylazine protocol.KEYWORDS: egg quality; glutamine; intestinal morphology; thermal stress.

A associação de um agonista -2 a um protocolo anestésico visa à sedação profunda, miorrelaxamento e analgesia potente, de forma a reduzir a quantidade de outros agentes anestésicos para se alcançar o plano anestésico ideal para a realização de procedimentos cirúrgicos. Neste estudo, avaliou-se comparativamente a qualidade da tranquilização, indução e recuperação da anestesia por isofluorano e infusão contínua de xilazina e medetomidina em 16 equinos e concluiu-se que, nesta espécie animal, o protocolo anestésico com medetomidina garante maior relaxamento muscular, melhor qualidade de indução e recuperação anestésica, embora apresente a mesma qualidade de tranquilização que a xilazina.PALAVRAS-CHAVE: agonistas -2; comportamento; equinos; infusão contínua; isofluorano.

Echocardiographic assessment after intravenous amitraz or xylazine injection in cats / Avaliação ecocardiográfica de gatos após a administração intravenosa de amitraz ou xilazina

Amitraz acts on a2-adrenergic receptors in a competitive and reversible way, leading to some xylazine-like effects. To evaluate the left ventricular function index after amitraz or xylazine administration, eight mongrel cats were submitted to intravenous injection: group X (xylazine), group A (amitraz) or group D (diluent). The same cats were used in all groups, after a 15-day interval. Heart rate (HR) and rhythm, shortening fraction (%SF), ejection fraction (%EF) and cardiac index (CI) were measured by echocardiography immediately before and during 60 minutes after drug injection. Amitraz and xylazine induced first-degree atrioventricular block (1st AVB) and decreases in HR, %SF, %EF and CI. The mean values of HR and all echocardiographic parameters of group X were significantly lower comparing to group A. It was concluded that both a2-agonists produce bradycardia and 1st AVB, but xylazine causes greater depression of the cardiac contractility.  KEYWORDS: Amitraz, xylazine, echocardiography, electrocardiography, cats

O amitraz age de forma competitiva e reversível em receptores adrenérgicos do tipo a2, desencadeando efeitos similares aos da xilazina. Com o objetivo de avaliar a função ventricular esquerda após a administração de amitraz ou xilazina, oito gatos SRD foram submetidos a injeções intravenosas: grupo X (xilazina), grupo A (amitraz) ou grupo D (diluente). Os mesmos animais foram utilizados em todos os grupos após um intervalo mínimo de quinze dias. Foram avaliados frequência cardíaca (FC), ritmo cardíaco, fração de ejeção (FE), fração de encurtamento (FS) e índice cardíaco (IC), por meio de eletrocardiografia e ecocardiografia, imediatamente antes e durante os primeiros sessenta minutos após a aplicação. Tanto o amitraz quanto a xilazina induziram bloqueio atrioventricular de primeiro grau (1º BAV) e diminuição de FC, FE, FS e IC. As médias da FC e de todos os parâmetros ecocardiográficos do grupo X foram estatisticamente menores do que as do grupo A. Concluiu-se que ambos os agonistas adrenérgicos de receptores tipo a2 causaram bradicardia e 1º BAV; contudo, a xilazina produziu maior depressão na contratilidade cardíaca. PALAVRAS-CHAVES: Amitraz, xilazina, ecocardiografia, eletrocardiografia, gatos.

Behavioral evaluation of the isoflurane anesthesia and xylazine and medetomidine continuous infusion in horses / Avaliação comportamental da anestesia por isofluorano e infusão contínua de xilazina e medetomidina em equinos

The association of an -2 agonist to an anesthetic protocol leads to deep sedation, muscle relaxation and potent analgesia, reducing the quantity of other anesthetic agents to reach the ideal anesthetic plan to the surgical procedure. This study evaluated comparatively the tranquilization, induction and recovery quality of the isofluorane anesthesia and xylazine and medetomidine continuous infusion in 16 horses. It was possible to conclude that, in this specie, the medetomidine protocol warrants wider muscle relaxation, better quality of anesthetic induction and recovery, even though it presents the same tranquilization quality of the xylazine protocol.KEYWORDS: egg quality; glutamine; intestinal morphology; thermal stress.

A associação de um agonista -2 a um protocolo anestésico visa à sedação profunda, miorrelaxamento e analgesia potente, de forma a reduzir a quantidade de outros agentes anestésicos para se alcançar o plano anestésico ideal para a realização de procedimentos cirúrgicos. Neste estudo, avaliou-se comparativamente a qualidade da tranquilização, indução e recuperação da anestesia por isofluorano e infusão contínua de xilazina e medetomidina em 16 equinos e concluiu-se que, nesta espécie animal, o protocolo anestésico com medetomidina garante maior relaxamento muscular, melhor qualidade de indução e recuperação anestésica, embora apresente a mesma qualidade de tranquilização que a xilazina.PALAVRAS-CHAVE: agonistas -2; comportamento; equinos; infusão contínua; isofluorano.

Comparison of analgesia provided by lidocaine, lidocaine-morphine or lidocaine-tramadol delivered epidurally in dogs following orchiectomy.

OBJECTIVE: To evaluate and compare the postoperative analgesia provided by epidural lidocaine, lidocaine/morphine or lidocaine/tramadol in dogs following elective orchiectomy. STUDY DESIGN: Prospective experimental trial. ANIMALS: Thirty-six mongrel dogs aged 2-8 years old, weighing 6.6-22 kg. METHODS: The dogs received 6.0 mg kg(-1) of lidocaine combined with 1.0 mg kg(-1) of tramadol, 0.1 mg kg(-1) of morphine or 0.01 mL kg(-1) of 0.9% NaCl epidurally. Analgesia was assessed at 4, 8, 12, 18 and 24 hours (T4, T8, T12 and T24) after the offset of lidocaine using a scale composed of physiologic and behavioral parameters. Rescue analgesia with morphine (0.2 mg kg(-1) , IM) was performed if the evaluation score exceeded 10 during the postoperative period. The scores over time were analyzed using the Friedman's two-way analysis of variance and the comparison between groups was made by the Kruskal-Wallis test with statistical significances accepted if p ≤ 0.05. RESULTS: There were no differences in the pain scores between the morphine and tramadol groups over time and no rescue analgesia was administered. In the NaCl group, rescue analgesia was needed at T4, T8 and T12. Within this group, the final evaluation times (T18 and T24) had lower pain scores than at T4, T8 and T12. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural lidocaine/tramadol provided an analgesic effect comparable to that of epidural lidocaine/morphine during the first 12 hours after surgical castration without substantial side effects, suggesting that tramadol may be an effective postoperative analgesic in dogs submitted to this surgical procedure.

Effects of meloxicam administered by different routes to control experimental uveitis in dogs / Efeitos do meloxicam, aplicado por diferentes vias, no controle de uveíte experimental em cães

Efficacy of meloxicam, administered by different routes was studied in experimental uveitis in dogs. Anterior chamber paracenteses was accomplished at two different moments (M0 and M1), with a five hour interval among them. At M0 and M1, 0.2mL of aqueous humor was collected and total protein and prostaglandin E2 (PGE2) quantitation was determined. Four groups were formed (n=5), which received meloxicam at the end of M0. by the following routes: subcutaneous (GIm), subconjunctival (GII), and topical (GIII). A fourth group that received no treatment was instituted (Control). Conjunctival histopathology of the GII was performed. Results were evaluated statistically (P≤0.05). In all groups, protein and PGE2 values enhanced significantly in M1. Protein and PGE2 values did not change significantly between groups at M1. Inflammatory exudate of acute character and mild hemorrhage were seen at histopathology, after meloxicam administration. Meloxicam were unable to inhibit PGE2 synthesis and the protein influx to the anterior chamber by any of the tested routes.

Foram estudados os efeitos do meloxicam, aplicado por diferentes vias, em uveítes experimentais em cães. Realizou-se paracentese de câmara anterior em dois momentos (M0 e M1), com intervalo de cinco horas entre si. Em M0 e M1, foram coletados 0,2mL de humor aquoso e determinou-se a concentração de proteína total e de prostaglandina E2 (PGE2). Constituíram-se quatro grupos (n=5), que receberam meloxicam ao final de M0 pelas vias subcutânea (GI), subconjuntival (GII) e tópica (GIII). Um quarto grupo não recebeu tratamento (Controle). Procedeu-se à avaliação histopatológica nos indivíduos do GII. Os resultados foram avaliados estatisticamente (p≤0,05). Em todos os grupos, encontrou-se aumento significativo dos níveis protéicos e de PGE2 em M1. Não se observou diferença significativa, em M1, entre os grupos para nenhum dos parâmetros estudados. Exsudado inflamatório de caráter agudo e hemorragia discreta foram vistos à histopatologia após a aplicação do meloxicam. O meloxicam foi ineficaz em inibir a síntese de PGE2 e o influxo de proteínas para a câmara anterior, por qualquer uma das vias testadas.

Some cardiopulmonary effects of sevoflurane in crested caracara (Caracara plancus).

OBJECTIVE: To evaluate the cardiorespiratory changes induced by sevoflurane (SEV) anesthesia in the crested caracara (Caracara plancus). STUDY DESIGN: Prospective experimental trial. ANIMALS: Eight crested caracaras (Caracara plancus) weighing 1.0 (0.9-1.1) kg were used for the study. METHODS: The birds were anesthetized by face mask with isoflurane for brachial artery catheterization. After recovery, anesthesia was re-induced with 6% SEV via face mask. After induction, a noncuffed endotracheal tube was placed and anesthesia was maintained with SEV (3.5% end-tidal) in oxygen (1 L minute(-1)) using an Ayre's T-piece nonrebreathing circuit, with spontaneous ventilation. Electrocardiography (ECG), direct systolic, diastolic and mean arterial blood pressure (SAP, DAP, and MAP), respiratory rate (f(R)), end-tidal carbon dioxide (Pe'CO(2)), and cloacal temperature (T degrees C) were measured before induction (baseline - under physical restraint) and after 5, 10, 15, 20, 25, 30, 35 and 40 minutes of SEV anesthesia. Arterial blood samples were collected for gas analysis at baseline and then at 10, 25 and 40 minutes. RESULTS: No ventricular arrhythmias were observed in the present study. Respiratory rate, SAP, DAP, MAP, T degrees C and pH decreased from pre-induction values, while arterial partial pressures of oxygen and carbon dioxide, bicarbonate concentration, and Pe'CO(2) were significantly higher than baseline. None of the birds were apneic. CONCLUSION AND CLINICAL RELEVANCE: Sevoflurane anesthesia is suitable for use in healthy members of this species, despite the moderate cardiovascular and respiratory depression produced.

Alterações morfométricas no plexo mioentérico do cólon menor equino distendido experimentalmente / Morphometrical alterations in myoenteric plexus of experimentally distended equine small colon

O cólon menor dos equinos é frequentemente acometido por afecções obstrutivas, sendo a disfunção da motilidade uma complicação comum após o tratamento cirúrgico. Este transtorno pode estar relacionado com lesões no plexo mioentérico ocorridas durante a distensão intestinal, contudo pouco se sabe sobre sua fisiopatologia. O objetivo deste estudo foi avaliar as alterações morfológicas na inervação mioentérica em segmentos de cólon menor de eqüinos submetidos à distensão intraluminal com pressão suficiente para promover redução da perfusão microvascular (isquemia parcial) da parede intestinal. Nove eqüinos foram submetidos à distensão do cólon menor por 4h. Fragmentos da parede intestinal foram colhidos antes e ao final da distensão, após 1,5 e 12 horas de reperfusão no segmento experimental e ao final do procedimento em segmento distante. As amostras foram fixadas e processadas rotineiramente e secções histológicas foram coradas com cresil violeta para a morfometria. Por meio de um software de análise de imagens, obtiveram-se a área, o perímetro e os diâmetros mínimo e máximo do corpo neuronal, do núcleo e do nucléolo dos neurônios e as áreas do citoplasma e do nucleoplasma. Verificou-se redução significativa (P<0,05) das áreas do corpo neuronal e do citoplasma ao final da distensão, retornando aos valores equivalentes aos iniciais durante a reperfusão. Conclui-se que a distensão intraluminal alterou morfologicamente os neurônios do plexo mioentérico. Essas modificações morfológicas podem estar associadas e contribuir para explicar a disfunção da motilidade freqüentemente observada em casos clínicos.

The equine small colon is frequently affected by obstruction, and intestinal motility dysfunction is a common complication after its surgical treatment. This fact may be related to myoenteric plexus lesion caused by distention; however, little is known about the pathophysiology of this condition. The objective of this study was to evaluate the morphological alterations in the myoenteric inervation of segments of small colon of horses subjected to intraluminal distension with reduction of the microvascular perfusion (partial ischemia) of the intestinal wall. Nine horses were used to promote distension of on segment of small colon for 4 hours. Samples of intestinal wall were collected before and at the end of the distension, after 1.5 and 12 hours of reperfusion in the experimental segment and at the end of the procedure in a different distant segment. Samples were processed and histological sections were stained with cresyl violet for the morphometric studies. An image analyzer software was used to measure perimeter, diameter, and area of the neuronal body, nucleus and nucleolus of the neurons and the areas of the cytoplasm and nucleoplasm. Significant reductions (P<0.05) in the areas of the neuronal body and cytoplasm were detected at the end of intestinal distension, returning to the basal values during the reperfusion. In conclusion, intraluminal distension promoted changes in the morphology of the neurons of myoenteric plexus. These morphological modifications may be associated to the motility dysfunction frequently observed in clinical cases.

Alterações morfométricas no plexo mioentérico do cólon menor equino distendido experimentalmente / Morphometrical alterations in myoenteric plexus of experimentally distended equine small colon

O cólon menor dos equinos é frequentemente acometido por afecções obstrutivas, sendo a disfunção da motilidade uma complicação comum após o tratamento cirúrgico. Este transtorno pode estar relacionado com lesões no plexo mioentérico ocorridas durante a distensão intestinal, contudo pouco se sabe sobre sua fisiopatologia. O objetivo deste estudo foi avaliar as alterações morfológicas na inervação mioentérica em segmentos de cólon menor de eqüinos submetidos à distensão intraluminal com pressão suficiente para promover redução da perfusão microvascular (isquemia parcial) da parede intestinal. Nove eqüinos foram submetidos à distensão do cólon menor por 4h. Fragmentos da parede intestinal foram colhidos antes e ao final da distensão, após 1,5 e 12 horas de reperfusão no segmento experimental e ao final do procedimento em segmento distante. As amostras foram fixadas e processadas rotineiramente e secções histológicas foram coradas com cresil violeta para a morfometria. Por meio de um software de análise de imagens, obtiveram-se a área, o perímetro e os diâmetros mínimo e máximo do corpo neuronal, do núcleo e do nucléolo dos neurônios e as áreas do citoplasma e do nucleoplasma. Verificou-se redução significativa (P<0,05) das áreas do corpo neuronal e do citoplasma ao final da distensão, retornando aos valores equivalentes aos iniciais durante a reperfusão. Conclui-se que a distensão intraluminal alterou morfologicamente os neurônios do plexo mioentérico. Essas modificações morfológicas podem estar associadas e contribuir para explicar a disfunção da motilidade freqüentemente observada em casos clínicos.(AU)

The equine small colon is frequently affected by obstruction, and intestinal motility dysfunction is a common complication after its surgical treatment. This fact may be related to myoenteric plexus lesion caused by distention; however, little is known about the pathophysiology of this condition. The objective of this study was to evaluate the morphological alterations in the myoenteric inervation of segments of small colon of horses subjected to intraluminal distension with reduction of the microvascular perfusion (partial ischemia) of the intestinal wall. Nine horses were used to promote distension of on segment of small colon for 4 hours. Samples of intestinal wall were collected before and at the end of the distension, after 1.5 and 12 hours of reperfusion in the experimental segment and at the end of the procedure in a different distant segment. Samples were processed and histological sections were stained with cresyl violet for the morphometric studies. An image analyzer software was used to measure perimeter, diameter, and area of the neuronal body, nucleus and nucleolus of the neurons and the areas of the cytoplasm and nucleoplasm. Significant reductions (P<0.05) in the areas of the neuronal body and cytoplasm were detected at the end of intestinal distension, returning to the basal values during the reperfusion. In conclusion, intraluminal distension promoted changes in the morphology of the neurons of myoenteric plexus. These morphological modifications may be associated to the motility dysfunction frequently observed in clinical cases.(AU)

Anestesia por isofluorano em eqüinos submetidos à infusão contínua de medetomidina ou xilazina / Isoflurane anesthesia in horses during medetomidine or xilazine continuous infusion

Avaliaram-se oito eqüinos sob anestesia geral inalatória com isofluorano (1CAM) e infusão contínua de xilazina (0,35mg kg-1h-1) ou medetomidina (3,5µg kg-1h-1), em relação à freqüência cardíaca, ritmo cardíaco, freqüência respiratória, pressão arterial, hemogasometria arterial e temperatura, nos tempos T0 (imediatamente antes do início da infusão contínua) e T10 ao T60 (intervalos de 10 minutos, após início da infusão contínua). Houve redução da freqüência cardíaca e da temperatura e elevação da pressão arterial média. A paCO2 (no GM) elevou-se e a paO2 mostrou-se maior no GM que no GX. Conclui-se que a infusão contínua de doses equipotentes de xilazina e medetomidina, durante anestesia geral inalatória, com isofluorano, em eqüinos, promove alterações cardiocirculatórias, respiratórias, térmicas e hemogasométricas discretas e equivalentes.

Eight horses under inhalant general anesthesia with isoflurane (1MAC) and continuous infusion of xylazine (0.35mg kg-1h-1) or medetomidine (3.5µg kg-1h-1) were evaluated for heart rate and rhythm, respiratory rate, arterial blood pressure, arterial blood gas analysis and temperature immediately before the beginning of the continuous infusion (T0) and in intervals of 10 minutes after the beginning of the continuous infusion (T10 to T60). Heart rate and temperature decreased and mean arterial pressure increased. PaCO2 (in GM) increased and GM showed a higher paO2 than GX. We conclude that equipotent doses of continuous infusion of medetomidine and xylazine during inhalant general anesthesia with isoflurane in horses promote slight and equivalent cardiocirculatory, respiratory, thermic and arterial blood gases changes.