Úlcera de pressão em pacientes internados em um hospital universitário em Natal/RN: condições predisponentes e fatores de risco

The pressure ulcers (PU), also known as decubitus ulcers, are defined as injuries caused by the constant pressure exerted on a particular point of the body, causing impairment of blood supply with a decrease or interruption of tissue irrigation, causing occlusion of blood vessels and capillaries, ischemia and cell death. This is a descriptive study with longitudinal design, and panel type, with quantitative approach that aimed to examine the association between predisposing conditions (PC), intrinsic factors (IF) and extrinsic factors (EF) with the occurrence of PU, in hospitalized patients in the Intensive Care Unit (ICU), pain clinical, surgical clinical and neurology wards of a university hospital. The study population was composed of all patients who were restricted to bed during the period from December 2007 to February 2008. The study was approved by the Ethics Committee of HUOL / UFRN (No 135/07). The data-collection took place through a structured formulary of observation, data from medical records and physical examination of patients skins. The results were organized in SPSS 15.0 software, tabulated, categorized and analyzed by descriptive and inferential statistics. Of the 30 patients studied, 43.3% had been hospitalized in the pain clinical and surgical clinic wards, 20.0% in the ICU, 20.0% in the ICU / ward and 16.7% in neurology, being the length of hospitalization in those units of 7 to 18 days (63.3%) and from 19 to 30 days (36.7%), predominantly female and aged ≥ 60 years (60.0%). 19 PU were diagnosed in 43.3% of patients monitored, being 38.5% with one PU between 7 to 18 days and 46.2% with two or more between 19 to 30 days of hospitalization, showing significant relationship (ρ-value = 0029) between length of hospital stay and the number of PU. Was found an association of 35.7% of the PC (cardio-respiratory, hematological, metabolic and psychogenic), IF (age group, oedema, skin changes in humidity and change of body temperature) and EF (type of mattress and strength of body pressure) for all patients studied, statistically significant (ρ-value = 0001), between the average scores in patients with and without PU, with reason chance to 12.0 for the development of PU and there was moderate correlation ( r = 0618) in the presence of this association. Results show the influence of the multiplicity of factors and conditions on the occurrence of PU, which brings us to reflect on the assistance focused on prevention and reduction of these injuries which will encourage the reduction of hospitalization length, physical and psychological suffering, and the possibility of improving the clinical condition of the patient.

Brain and hepatic Hsp70 protein levels in heat-acclimated broiler chickens during heat stress

In the present study we have investigated the effects of heat acclimation on brain and hepatic Hsp70 protein levels and body temperature of broiler chickens in response to gradual heat stress. Two groups of broilers were raised up to 47 days of age under distinct temperature conditions: thermoneutral (TN, according to bird age) or hot environmental (HS, 31-33°C). At 46 days of age, the birds reared at high ambient temperature were transferred to thermoneutrality conditions. After 18 h, these birds and the birds reared at thermoneutral temperature were submitted to gradual heat stress in a climatic chamber so that environment temperature was increased from 28 to 40ºC at a rate of 2ºC/h. Colonic temperature was measured using a thermometer sensor probe at each two hours, and hepatic and brain tissues were collected immediately after slaughter in order to assess Hsp70 protein level by Western blotting analysis. The colonic temperatures of birds reared at high temperature increased steeply during the first 2 h of heat stress (1.06ºC/h) and more slowly thereafter (0.59ºC/h). Broilers reared at thermoneutral temperature showed a small increase in the first 4 h of heat stress (0.18ºC/h) and then colonic temperature increased sharply (0.72ºC/h). Nevertheless, both groups presented similar final colonic temperature by the end of the stress period. Hsp70 levels (ng Hsp70 µg total protein-1) did not change in the liver or brain of the birds reared at high temperature. on the other hand, both liver and brain Hsp70 levels increased significantly during heat stress in the animals reared at thermoneutrality, with a higher expression of this peptide in brain tissue.

Desempenho, Temperatura Corporal e Qualidade dos Ovos de Poedeiras Alimentadas com Vitaminas D e C em Três Temperaturas Ambiente

O experimento foi conduzido em câmara climática para determinar os efeitos das vitaminas D3 e C sobre o desempenho, temperatura corporal e qualidade dos ovos de poedeiras em três temperaturas: termoneutra (24,8º a 27,0º C), estresse calórico cíclico (26,2º C por 16h e 32,1º C por 8h) e estresse calórico constante (30,0º a 32,0º C). Foram utilizadas 144 galinhas brancas com 31 semanas num delineamento inteiramente ao acaso em arranjo fatorial 3x3x3: vitamina D3 (2500, 3000 e 3500 UI/kg), vitamina C (0, 200 e 400 ppm) e temperatura ambiente (termoneutra, estresse calórico cíclico e constante). As características avaliadas foram: consumo de ração (CR), produção de ovos (PO), peso dos ovos (PE), massa de ovos (MO), conversão alimentar (CA), porcentagens de albúmem (AL) e de gema (GE), unidade Haugh (UH), índice de gema (IG), porcentagem de casca (PC), espessura de casca (EC), gravidade específica dos ovos (GO), temperaturas dorsal (TD) e retal (TR). A vitamina D3 interferiu nas características PC, EC, GO e TD; a vitamina C no IG, PC e GO. A temperatura ambiente não afetou somente a UH. Concluiu-se que níveis mais altos de vitamina D3 e níveis de 200 ou 400 ppm de vitamina C na dieta podem melhorar a qualidade da casca e que o estresse calórico prejudicou as principais características avaliadas.

A technique for the capture of free-ranging marsh deer (blastocerus dichotomus)

The marsh deer (Blastocerus dichotomus) is an endangered species froth the marshlands of central South America. Its population has declined in several regions due to the loss of available habitat caused by human activities, especially the construction of hydroelectric darns. The capture of individual deer is critical for research programs and population management. This report describes a novel live-capture technique, which uses a helicopter to drive the animals into a terrain that restricts their movement such as thick vegetation or deep water (60-120 cm in depth). Following confinement, animals are manually restrained. The short pursuit time (median = 2 thin), low mortality rate (0.82-3.28%), and the absence of injury to both the capture team and animals suggest that this method is appropriate for the safe capture of this species. Body temperature correlated with the pursuit time (R-2 = 0.15) but was not significantly altered with pursuit times <3 min.

Rheological, mechanical and mucoadhesive properties of thermoresponsive, bioadhesive binary mixtures composed of poloxamer 407 and carbopol 974P designed as platforms for implantable drug delivery systems for use in the oral cavity

This study described the formulation and characterisation of the viscoelastic, mechanical and mucoadhesive properties of thermoresponsive, binary polymeric systems composed of poloxamer (P407) and poly(acrylic acid, C974P) that were designed for use as a drug delivery platform within the oral cavity. Monopolymeric and binary polymeric formulations were prepared containing 10, 15 and 20% (w/w) poloxamer (407) and 0.10-0.25% (w/w) poly(acrylic acid, 934P). The flow theological and viscoelastic properties of the formulations were determined using controlled stress and oscillatory rheometry, respectively, the latter as a function of temperature. The mechanical and mucoadhesive properties (namely the force required to break the bond between the formulation and a pre-hydrated mucin disc) were determined using compression and tensile analysis, respectively. Binary systems composed of 10% (w/w) P407 and C934P were elastoviscous, were easily deformed under stress and did not exhibit mucoadhesion. Formulations containing 15 or 20% (w/w) Pluronic P407 and C934P exhibited a sol-gel temperature T(sol/gel), were viscoelastic and offered high elasticity and resistance to deformation at 37 degrees C. Conversely these formulations were elastoviscous and easily deformed at temperatures below the sol-gel transition temperature. The sol-gel transition temperatures of systems containing 15% (w/w) P407 were unaffected by the presence of C934P; however, increasing the concentration of C934P decreased the T(sol/gel) in formulations containing 20%(w/w) P407. Rheological synergy between P407 and C934P at 37 degrees C was observed and was accredited to secondary interactions between these polymers, in addition to hydrophobic interactions between P407 micelles. Importantly, formulations composed of 20% (w/w) P407 and C934P exhibited pronounced mucoadhesive properties. The ease of administration (below the T(sol/gel)) in conjunction with the viscoelastic (notably high elasticity) and mucoadhesive properties (at body temperature) render the formulations composed of 20% (w/w) P407 and C934P as potentially useful platforms for mucoadhesive, controlled topical drug delivery within the oral cavity. (c) 2009 Published by Elsevier B.V.

Avaliação da resposta comportamental, morfofisiológica e produção de leite de cabras puras e mestiças da raça Saanen no semi-árido do Rio Grande do Norte

Goat breeding in the state of Rio Grande do Norte, Brazil has promising economic possibilities, with the proper handling of the natural resources. The introduction of specialized animals has been one of the ways used to improve herd genetics and increase productivity. However, climate has been one of the regional factors that most interferes with the adaptation of the new genetic prevalence resulting from the introduction of exotic breeds, because in their country of origin, the air temperature during most of the year is lower than the animals body temperature. With this in mind, the aim of this study was to characterize behavioral, physiological and morphological profiles and milk production of female Saanen goats belonging to different genetic groups raised in the semi-arid region of Rio Grande do Norte in Northeast Brazil. The study was conducted in the city of Lages (5° 42 00 S and 36° 14 41 W). We used 25 lactating female Saanen goats, distributed into 3 genetic groups: 5 purebred animals, 11 three-quarter bred and 9 half-bred. Behavioral observations were made over three consecutive days in the months of August and September, between 09:00 and 11:30h, when the animals were grazing. Physiological and meteorological data were recorded in the last three days of June, July, August and September at 05:00h and at 16:00h. In the semi-intensive breeding system, the animals from different genetic groups were similar in both field behavior and physiological response patterns. Although the purebred goats had longer hair, they did not show symptoms of thermal discomfort. Their white hair helped to reflect the short wavelength rays and thus eliminate those at the longer wave lengths. We concluded that the animals raised in the semi-intensive milk production system in this study seem to have adapted to the climatic conditions of the semi-arid region of Rio Grande do Norte, Brazil

Ecologia comportamental de tropidurus Hispidus e Tropidurus Semitaeniatus (Squamata, Tropiduridae) em Simpatria, em área de caatinga do nordeste do Brasil.

This study evaluated the spatial, time and alimentary niches of Tropidurus hispidus and Tropidurus semitaeniatus in sympatry in a caatinga of Rio Grande do Norte, Brazil, as well as their foraging and termoregulatory behaviors, the activity body temperature and their reproductive and fat body cycles. Monthly excursions, from October 2006 to May 2008, were conducted at the Ecological Station of the Seridó (ESEC Seridó), Serra Negra do Norte municipality, using specific methodology for investigation of the aforementioned objectives. The two species presented similarities in space niche use, mainly in rocky habitat, however they differed in vertical microhabitat use with T. hispidus using a larger vertical microhabitat range. In the dry season the time of activity of both species was bimodal. In the wet season T. semitaeniatus showed a unimodal activity period, while T. hispidus maintained an bimodal activity period. In terms of importance in the diet, to both species, Hymenoptera/Formicidae and Isoptera predominated during the dry season. In the wet season, although Hymenoptera/Formicidae had larger importance among the prey items, lizards opportunistically predated on Lepidoptera larvae, Coleoptera larvae/adults and Orthoptera nymphs/adults. The foraging intensity revealed differences between the species, mainly in the wet season, when T. semitaeniatus was more active than T. hispidus. The mean activity body temperature of T. semitaeniatus was significantly higher than that of T. hispidus. The thermoregulatory behavior showed that during the dry season T. hispidus and T. semitaeniatus spent more time in shade or under filtered sun. In the wet season, T. hispidus did not show differences in the amount of time spent among the light exposure locations, however T. semitaeniatus spent most of their time exposed to direct sun or filtered sun. The reproductive cicle of T. hispidus and T. semitaeniatus occurred from the middle of the dry season to the beginning of the wet season. In both species, female reproductive activity was influenced by precipitation, whereas males exhibited spermatozoa in their testes throughout the year, and their reproductive activity was not related with any of the climatic variables analysed. In the two species, the fat storage varied inversely with reproductive activity, and there was no difference in fat body mass between females and males. We concluded that the segregation between T. hispidus and T. semitaeniatus in this caatinga area occurs in vertical space use, in the largest vagility of T. hispidus in microhabitat use and larger range size of their alimentary xviii items. Additionally, significant seasonal differences in relation to the activity period, body temperature, and foraging and termoregulatory behaviors between these two Tropidurus species facilitate their coexistence.

Estrutura da Comunidade de Lagartos de um remanescente de mata atlântica do Estado do Rio Grande Do Norte, Brasil.

As part of a broader project, Diversity and Distribution Patterns of Floristic and Faunistic composition of remnants of Potiguar s Atlantic Forest, as subsidies to conservation , that subsidizes a group of institutional research, This study aimed to evaluate the structure of the assemblage of lizards a remnant of the of the northern Atlantic Forest, identifying ecological factor (s) that contribute to the coexistence of sympatric species. Additionally, we studied the thermal ecology and thermoregulatory behavior of umbrophily and heliophily species live the Parque Estadual Mata da Pipa (PEMP), a remnant of Atlantic forest located in the Tibau do Sul municipality of, Rio Grande do Norte State, Brazil. It is one of the largest remnants of the Atlantic Forest and has an area of approximately 290 ha. The study was performed by four excursions to the field for 20 days each, when active search and pitfalls traps were used to record and colleted specimens in different habitats of the area. We recorded the presence of 19 species of lizards, of which seven are typical of forest areas, three are endemic Atlantic Forest, these two northern and one are new record for the Rio Grande do Norte. The use of resources, the results showed that phylogenetically related species do not always use a similar way the resources available; the feeding niche was the segregated component of the species that overlapped extensively in the use of space and vice versa. To examine the thermal ecology and thermoregulatory behavior of Kentropyx calcarata and Coleodactylus natalensis, we recorded the clocal temperature (Tc), oh the substrate (Ts) and of the air (Ta) to investigate what of these are the source of heat more important to the temperature s body of these lizards. Behavioral observations were conducted to analyze strategies to optimize the acquisition of heat. The air temperature explained most strongly to variation in body temperature of K. calcarata, while the temperature of the substrate to C. natalensis. As for the behavioral observations, they confirmed that K. calcarata is an active thermoregulatory; C. natalensis is a passive thermoregulatory.

O efeito da dessincronização circadiana sobre o metabolismo

The lost of phase relationship between rhythms and behaviour can, and often do, undesirable consequences. The purpose os study was to ascertain the effect of circadian desynchronization in T22 about metabolism of wistar rats. The subjects consisted of 24 animals separated in two groups: control (n=12) T24 with 8 weeks of aged and experimental group (n=12) T22, also with 8 weeks of aged. Both the groups were subject to register of locomotor actitivity, body temperature, body weight and food intake in all the experiment. And more, both the groups were subject to food deprivation, running in treadmill and forced swimming. The results show rhythm of locomotor activity and body temperature desynchronized. Dont exist diference in body weight between both the groups (T24 = 386,75±40,78g e T22 380,83±44,28g) . However, the food intake was different between the phases, light and dark, in intergroup and intragroup. The body temperature was not different in food deprivation. The same ocurred for running in treadmill and forced swimming. Since similar alterations occur in shift workers, it is proposed that the experimental paradigm presented in this manuscript is a useful model of shift work. That is, alterations in activity/rest cycles and consummatory behavior can affect the health of organism

Intraoperative lactate levels and postoperative complications of pediatric cardiac surgery

Objectives: Correlate arterial lactate levels during the intraoperative period of children undergoing cardiac surgery and the occurrence of complications in the postoperative period. Aim: Arterial lactate levels can indicate hypoperfusion states, serving as prognostic markers of morbidity and mortality in this population. Background: Anesthesia for cardiac pediatric surgery is frequently performed on patients with serious abnormal physiological conditions. During the intraoperative period, there are significant variations of blood volume, body temperature, plasma composition, and tissue blood flow, as well as the activation of inflammation, with important pathophysiological consequences. Methods/Materials: Chart data relating to the procedures and perioperative conditions of the patients were collected on a standardized form. Comparisons of arterial lactate values at the end of the intraoperative period of the patients that presented, or not, with postoperative complications and frequencies related to perioperative conditions were established by odds ratio and nonparametric univariate analysis. Results: After surgeries without cardiopulmonary bypass (CPB), higher levels of arterial lactate upon ICU admission were observed in patients who had renal complications (2.96 vs 1.31 mm) and those who died (2.93 vs 1.40 mm). For surgeries with CPB, the same association was observed for cardiovascular (2.90 mm x 2.06 mm), renal (3.34 vs 2.33 mm), respiratory (2.98 vs 2.12 mm) and hematological complications (2.99 vs 1.95 mm), and death (3.38 vs 2.40 mm). Conclusion: Elevated intraoperative arterial lactate levels are associated with a higher morbidity and mortality in low- and medium-risk procedures, with or without CPB, in pediatric cardiac surgery.

Evaluation of Hemodynamic, Metabolic, and Electrolytic Changes After Graft Reperfusion in a Porcine Model of Intestinal Transplantation

Background. We sought to establish an anesthetic protocol to evaluate the hemodynamic, metabolic, and electrolytic changes after graft reperfusion in pigs undergoing orthotopic intestinal transplant (ITX).Methods. Fifteen pigs were distributed into two groups: GI (n = 6), without immunosuppression, and GII (n = 9), immunosuppressed before surgery with tacrolimus (0.3 mg/kg). The animals were premedicated at 1 hour before surgery with IM acepromazine (0.1 mg/kg), morphine (0.4 mg/kg), ketamine (10 mg/kg), and atropine (0.044 mg/kg IM). Anesthesia induction used equal proportions of diazepam and ketamine (0.1-0.15 mL/kg/IV) and for maintenance in IV infusion of xylazine (1 mg/mL), ketamine (2 mg/mL), and guaiacol glyceryl ether 5% (50 mg/mL), diluted in 250 mL of 5% glucose solution. In addition, recipient pigs were treated with isofluorane inhalation. Heart rate (HR), systolic (SAP), mean (MAP), and diastolic (DAP) arterial pressure, pulse oximetry, respiratory frequency (f), capnography, body temperature (T), blood gas analysis (pH, PaCO(2), PaO(2), base excess, BE; HCO(3)(-), SatO(2)), serum potassium (K), calcium (Ca), sodium, hematocrit (Hct), and glucose (Glu) were measured at four times; MO: after incision (basal value); M1: 10 minutes before reperfusion; and M2 and M3: 10 and 20 minutes after graft reperfusion.Results. All groups behaved in a similar pattern. There was significant hypotension after graft reperfusion in GI and GII (M2 = 56.2 +/- 6.4 and M3 = 57.2 +/- 8.3 mm Hg and M2 = 65.7 +/- 10.2 and M3 = 67.8 +/- 16.8 mm Hg, respectively), accompanied by elevated HR. The ETCO(2) was elevated at M2 (42 mm Hg) and M3 (40 mm Hg). Metabolic acidosis was observed after reperfusion, with significant increase in K levels.Conclusion. The anesthetic protocol for donors and recipients was safe to perform the procedure, allowing control of hemodynamic and metabolic changes after reperfusion without differences regarding immunosuppression.

Caracterização do perfil do ciclo sono-vigília em ratos sob dessincronização forçada

The circadian behavior associated with the 24 hours light-dark (LD) cycle (T24) is due to a circadian clock , which in mammals is located in the hypothalamic suprachiasmatic nucleus (SCN). Under experimental conditions in which rats are espoused to a symmetric LD 22h cycle (T22) the two SCN regions, ventrolateral (vl) and dorsomedial (dm), can be functionally isolated, suggesting that each region regulates distinct physiological and behavioral components. The vl region regulates the locomotor activity and slow wave sleep (SWS) rhythms, while the dm region assures the body temperature and paradoxical sleep (PS) rhythms regulation. This research aimed to deepen the knowledge on the functional properties of circadian rhythmicity, specifically about the internal desynchronization process, and its consequences to locomotor activity and body temperature rhythms as well as to the sleep-wake cycle pattern in rats. We applied infrared motion sensors, implanted body temperature sensors and a telemetry system to record electrocorticogram (ECoG) and electromyogram (EMG) in two rat groups. The control group under 24h period LD cycle (T24: 12hL-12hD) to the baseline record and the experimental group under 22h period LD cycle (T22: 11hL- 11hD), in which is known to occur the uncoupling process of the circadian locomotor activity rhythm where the animals show two distinct locomotor activity rhythms: one synchronized to the external LD cycle, and another expressed in free running course, with period greater than 24h. As a result of 22h cycles, characteristic locomotor activity moment appear, that are coincidence moments (T22C) and non coincidence moments (T22NC) which were the main focus or our study. Our results show an increase in locomotor activity, especially in coincidence moments, and the inversion of locomotor activity, body temperature, and sleep-wake cycle patterns in non coincidence moments. We can also observe the increase in SWS and decrease in PS, both in coincidence and non coincidence moments. Probably the increases in locomotor activity as a way to promote the coupling between circadian oscillators generate an increased homeostatic pressure and thus increase SWS, promoting the decreasing in PS

Influência da temperatura corporal de cascavéis (Crotalus durissus) submetidas à anestesia com cetamina

O estudo objetivou verificar a influência da temperatura corporal nos parâmetros fisiológicos e nos períodos de indução e recuperação anestésicos de cascavéis (Crotalus durissus) anestesiadas com cetamina. Os animais foram previamente submetidos à hipotermia (HIPO) (<22°C) e normotermia (30°C) (NORMO) e anestesiados com 80mg/kg IM de cetamina. Foram avaliados os períodos de latência e recuperação da anestesia por meio do tônus de cabeça, tônus muscular e reflexo de endireitamento. Mensurou-se a frequência cardíaca (FC), tempo de apnéia e temperatura corporal em 0 min e 5, 10, 15, 30, 60, 90, 120 min e análise dos gases sanguíneos em 0 min, 30 e 60 min. Não houve diferença em relação ao período de latência entre os grupos. A recuperação dos animais em HIPO foi mais prolongada (5,5 horas) que em NORMO (3,5 horas). Obteve-se FC no grupo NORMO superior que no grupo HIPO. O tempo de apnéia manteve o mesmo padrão em ambos os grupos. em relação ao basal, tanto em HIPO quanto em NORMO o tempo de apnéia diminuiu acentuadamente entre 5 e 30 min. Observou-se acidose respiratória no grupo NORMO apenas em 0 min. O SvO2 elevou-se significativamente após 30 min, o mesmo ocorrendo com a PvO2. A PvCO2 diminuiu em ambos os grupos após 30 min. Evidenciou-se que a temperatura corporal influencia intrinsecamente o período de recuperação de cascavéis anestesiadas com cetamina.

Comparative study on the sedative effects of morphine, methadone, butorphanol or tramadol, in combination with acepromazine, in dogs

To compare the effects of morphine (MOR), methadone (MET), butorphanol (BUT) and tramadol (TRA), in combination with acepromazine, on sedation, cardiorespiratory variables, body temperature and incidence of emesis in dogs.Prospective randomized, blinded, experimental trial.Six adult mixed-breed male dogs weighing 12.0 +/- 4.3 kg.Dogs received intravenous administration (IV) of acepromazine (0.05 mg kg(-1)) and 15 minutes later, one of four opioids was randomly administered IV in a cross-over design, with at least 1-week intervals. Dogs then received MOR 0.5 mg kg(-1); MET 0.5 mg kg(-1); BUT 0.15 mg kg(-1); or TRA 2.0 mg kg(-1). Indirect systolic arterial pressure (SAP), heart rate (HR), respiratory rate (f(R)), rectal temperature, pedal withdrawal reflex and sedation were evaluated at regular intervals for 90 minutes.Acepromazine administration decreased SAP, HR and temperature and produced mild sedation. All opioids further decreased temperature and MOR, BUT and TRA were associated with further decreases in HR. Tramadol decreased SAP whereas BUT decreased f(R) compared with values before opioid administration. Retching was observed in five of six dogs and vomiting occurred in one dog in MOR, but not in any dog in the remaining treatments. Sedation scores were greater in MET followed by MOR and BUT. Tramadol was associated with minor changes in sedation produced by acepromazine alone.When used with acepromazine, MET appears to provide better sedation than MOR, BUT and TRA. If vomiting is to be avoided, MET, BUT and TRA may be better options than MOR.

Effects of methadone, alone or in combination with acepromazine or xylazine, on sedation and physiologic values in dogs

Objective To evaluate the effects of methadone, administered alone or in combination with acepromazine or xylazine, on sedation and on physiologic values in dogs.Study design Randomized cross-over design.Animals Six adult healthy mixed-breed dogs weighing 13.5 +/- 4.9 kg.Methods Dogs were injected intramuscularly with physiologic saline (Control), or methadone (0.5mg kg(-1)) or acepromazine (0.1 mg kg(-1)) or xylazine (1.0 mg kg(-1)), or acepromazine (0.05 mg kg(-1)) plus methadone (0.5 mg kg(-1)) or xylazine (0.5 mg kg(-1)) plus methadone (0.5 mg kg(-1)) in a randomized cross-over design, with at least 1-week intervals. Sedation, pulse rate, indirect systolic arterial pressure, respiratory rate (RR), body temperature and pedal withdrawal reflex were evaluated before and at 15-minute intervals for 90 minutes after treatment.Results Sedation was greater in dogs receiving xylazine alone, xylazine plus methadone and acepromazine plus methadone. Peak sedative effect occurred within 30 minutes of treatment administration. Pulse rate was lower in dogs that received xylazine either alone or with methadone during most of the study. Systolic arterial pressure decreased only in dogs receiving acepromazine alone. When methadone was administered alone, RR was higher than in other treatments during most of the study and a high prevalence of panting was observed. In all treatments body temperature decreased, this effect being more pronounced in dogs receiving methadone alone or in combination with acepromazine. Pedal withdrawal reflex was absent in four dogs receiving methadone plus xylazine but not in any dog in the remaining treatments.Conclusions Methadone alone produces mild sedation and a high prevalence of panting. Greater sedation was achieved when methadone was used in combination with acepromazine or xylazine. The combination xylazine-methadone appears to result in better analgesia than xylazine administered alone. Both combinations of methadone/sedative were considered effective for premedication in dogs.