Comparison between a Tail Clamp and Electrical Stimulation for Sevoflurane Minimum Anesthetic Concentration Determination in Green Iguanas (Iguana iguana).

This study aimed to compare the minimum anesthetic concentration (MAC) of sevoflurane in green iguanas using electrical stimulation and tail clamping as noxious stimuli. Seven adult green iguanas (Iguana iguana) weighing 580 to 1,300 g were enrolled. Each iguana was anesthetized twice after a 1-week washout period, with MAC being determined using a tail clamp (MACt) or electrical stimulation (MACe) techniques. After sevoflurane mask induction and endotracheal intubation, the fraction of expired sevoflurane (Fe'Sevo) was maintained at 3.1% for 15 min before noxious stimulation. In a bracketing design, the subsequent Fe'Sevo values were increased or decreased by 10% after positive or negative responses, respectively. Each targeted Fe'Sevo was kept constant for 15 min before stimulation. In MACt, the noxious stimulus involved closing a Kelly hemostatic curved forceps to the first ratchet at the base of the tail. At the same site, in MACe, 2 30 × 0.8-mm hypodermic needles inserted 1 cm apart were connected to an electrical stimulator set to deliver 30 mA at 50 Hz at a 6.5-ms interval. The hemostat and the needles were repositioned 2 cm distally and on alternate tail sides at each stimulation round. Individual MAC was obtained when 2 consecutive crossover events occurred (a positive response preceding a negative response or vice versa), with the MAC of each group represented by the average of the individual MAC values. Median (interquartile range) values for the sevoflurane MAC did not differ significantly between groups (2.2 [2.2 to 2.8%] in MACe and 2.2 [1.8 to 3.5%] in MACt; P = 0.812). Time to anesthesia induction, time to MAC measurement, heart rate (HR), end-tidal carbon dioxide (ET'CO2), and cloacal temperature were not different between groups. Both the tail-clamping and the electrical stimulation techniques yielded resembling sevoflurane MAC values in green iguanas, which makes the tail clamp a reliable alternative to electrical stimulation-based MAC research in this species.

The fraction of inspired oxygen does not affect the time to extubation in mechanically ventilated, sevoflurane-anesthetized green sea turtles (Chelonia mydas).

OBJECTIVE: To evaluate the effects of providing 100% O2, compared with the provision of 21% O2 (equivalent to room air), in mechanically ventilated, sevoflurane-anesthetized green sea turtles (Chelonia mydas). ANIMALS: Eleven juvenile green sea turtles. PROCEDURES: In a randomized, blinded, cross-over study (1-week interval between treatments), turtles were anesthetized with propofol (5 mg/kg, IV), orotracheally intubated, mechanically ventilated with 3.5% sevoflurane diluted in 100% O2 or 21% O2 for 90 minutes. Sevoflurane delivery immediately ceased and animals remained under mechanical ventilation with the assigned fraction of inspired oxygen until extubation. Recovery times, cardiorespiratory variables, venous blood gases, and lactate values were evaluated. RESULTS: Cloacal temperature, heart rate, end-tidal partial pressure of carbon dioxide, and blood gases were unremarkable between treatments. The SpO2 was higher with the provision of 100% O2 than 21% O2 during both anesthesia and recovery (P < .01). Time to bite the bite block was longer in 100% O2 (51 [39-58] minutes) than in 21% O2 (44 [31-53] minutes; P = .03), while time to first muscle movement, attempt to extubate, and extubation were comparable between treatments. CLINICAL RELEVANCE: Blood oxygenation appears to be lower during sevoflurane anesthesia in room air than in 100% O2, though both fractions of inspired oxygen were able to supply the aerobic metabolism of turtles based on acid-base profiles. In relation to room air, the provision of 100% O2 did not produce meaningful effects on the time to recovery in mechanically ventilated green turtles submitted to sevoflurane anesthesia.

Cardiopulmonary and propofol-sparing effects of dexmedetomidine in total intravenous anesthesia in cats undergoing ovariohysterectomy.

OBJECTIVES: This study aimed to assess the effect of dexmedetomidine on the propofol-based anesthesia of cats subjected to ovariohysterectomy. METHODS: Twenty-eight cats were randomly allocated to four groups (seven cats in each) and premedicated with either 5 µg/kg dexmedetomidine (groups Dex 1, Dex 3 and Dex 5) or 0.05 ml saline (Prop group) intramuscularly. After the induction of anesthesia with propofol, total intravenous anesthesia was initiated with 300 µg/kg/min propofol plus 3 ml/kg/h NaCl 0.9% (Prop), or 200 µg/kg/min propofol plus dexmedetomidine at the rates of 1 µg/kg/h (Dex 1), 3 µg/kg/h (Dex 3) or 5 µg/kg/h (Dex 5). Cardiorespiratory variables were assessed 5 mins after induction and every 10 mins thereafter, until the end of anesthesia. The propofol infusion rate was adjusted every 10 mins (± 50 µg/kg/min) to maintain anesthetic depth. The times to extubation, sternal recumbency, ambulation and total recovery were recorded. Pain scoring was performed 1, 2, 4, 8, 12 and 24 h after the end of anesthesia. RESULTS: Dexmedetomidine produced a propofol-sparing effect of 72.8%, 71.1% and 74.6% in the Dex 1, Dex 3 and Dex 5 groups, respectively. Cats in the Prop group maintained higher heart rate values than the other groups, and the mean arterial pressure remained higher in the Dex 3 and Dex 5 groups. Rescue intraoperative analgesia (fentanyl bolus) was most frequent in the Prop group. There was no significant difference in the time of extubation. Cats in the Dex 1 and Dex 3 groups had a faster anesthetic recovery, with shorter times to achieving sternal recumbency, regaining ambulation and reaching full recovery. Cats in the Dex 1 and Dex 5 groups presented the best recovery quality scores, with 4 (range 4-5) and 4 (range 3-5), respectively, while the Prop group scored 1 (range 1-3), the worst anesthetic recovery score among the groups. CONCLUSIONS AND RELEVANCE: The use of dexmedetomidine as a total intravenous anesthesia adjuvant, especially at doses of 1 and 3 µg/kg/h, reduces propofol consumption and improves cardiorespiratory stability and intraoperative analgesia, while promoting a better and quicker recovery from anesthesia.

Intranasal oxygen reverses hypoxaemia in immobilised free-ranging capybaras (Hydrochoerus hydrochaeris).

Capybara (Hydrochoerus hydrochaeris) is the main host of tick-borne pathogens causing Brazilian spotted fever; therefore, controlling its population is essential, and this may require chemical restraint. We assessed the impact of chemical restraint protocols on the partial pressure of arterial oxygen (PaO2) and other blood variables in 36 capybaras and the effect of different flows of nasal oxygen (O2) supplementation. The capybaras were hand-injected with dexmedetomidine (5 µg/kg) and midazolam (0.1 mg/kg) and butorphanol (0.2 mg/kg) (DMB, n = 18) or methadone (0.1 mg/kg) (DMM, n = 18). One-third of the animals were maintained in ambient air throughout the procedure, and one-third were administered intranasal 2 L/min O2 after 30 min whereas the other third were administered 5 L/min O2. Arterial blood gases, acid-base status, and electrolytes were assessed 30 and 60 min after drug injection. The DMB and DMM groups did not vary based on any of the evaluated variables. All animals developed hypoxaemia (PaO2 44 [30; 73] mmHg, SaO2 81 [62; 93] %) 30 min before O2 supplementation. Intranasal O2 at 2 L/min improved PaO2 (63 [49; 97] mmHg and SaO2 [92 [85; 98] %), but 9 of 12 capybaras remained hypoxaemic. A higher O2 flow of 5 L/min was efficient in treating hypoxaemia (PaO2 188 [146; 414] mmHg, SaO2 100 [99; 100] %) in all the 12 animals that received it. Both drug protocols induced hypoxaemia, which could be treated with intranasal oxygen supplementation.

Effects of Three Consecutive Days of Morphine or Methadone Administration on Analgesia and Open-Field Activity in Mice with Ehrlich Carcinoma.

This study assessed the exploratory behavioral responses in BALB/c mice inoculated with Ehrlich ascitic carcinoma after 3 consecutive days of treatment with morphine or methadone. Fifty-three female mice, 60 ± 10 d old, were used. Seven days after intraperitoneal tumor inoculation (2 × 106 cells), the animals were randomized into 7 groups: morphine 5 mg/kg (MO5), morphine 7.5 mg/kg (MO7.5), morphine 10 mg/kg (MO10), methadone 2.85 mg/kg (ME2.85), methadone 4.3 mg/kg (ME4.3), methadone 5.7 mg/kg (ME5.7), and 0.9% NaCl (Saline) (n = 7). Drug treatments were administered subcutaneously every 6 h for 3 d. The animals were evaluated for analgesia using the mouse grimace scale (MGS) and for general activity using the open field test. The MGS was performed before tumor inoculation (day 0), on day 7 at 40, 90, 150, 240, and 360 min after drug injection, and on days 8 and 9 at 40, 150, 240, and 360 min after drug injection. The open field test was performed before tumor inoculation (day 0), on day 7 after inoculation at 40, 90, 150, 240, and 360 min after drug injection, and on days 8 and 9 after inoculation at 40, 150, and 360 min after drug injection. MGS results indicated that administration of morphine promoted analgesia for up to 240 min. Conversely, methadone reduced MGS scores only at 40 min. All tested doses promoted a significant dose-dependent increase in the total distance traveled and the average speed, and increase that was markedly pronounced on days 8 and 9 as compared with day 7. The frequencies of rearing and self-grooming decreased significantly after morphine or methadone administration. Despite the difference in analgesia, both drugs increased locomotion and reduced the frequency of rearing and self-grooming as compared with the untreated control animals.

The Use of Bone Marrow-Derived Stem Cells in the Treatment of a Comminuted Tibiotarsal Fracture in a Juvenile Red-legged Seriema (Cariama cristata).

An adult red-legged seriema (Cariama cristata) presented with a comminuted fracture of the tibiotarsus and fibula. Surgery was performed, and a type II external fixator, with 2 distal and 2 proximal pins, was used to stabilize the fracture. After a 10-day stabilization period, the bird developed a second fracture on the same bone, proximal to the first fracture site. Another surgery was performed on the seriema similar to the first one. However, in this second surgical procedure a single pin, instead of 2 perpendicular pins, was placed proximally to the fracture site. After the second surgical procedure, bone marrow stem cells (BMSCs) from the seriema's left ulna were collected. Twenty-seven days after the second surgery, the BMSCs were transplanted, into the fracture sites. Twenty-four days after the stem cells were injected into the fractures (51 days after the second surgical procedure), radiographic images revealed healing bone calluses at the fracture sites. The fracture healing was relatively long for this case (a total of 75 days). The addition of bone marrow stem cell therapy to the use of external fixation may have contributed to the healing observed radiographically 24 days after administration; therefore, bone marrow stem cell therapy, in addition to traditional surgical fracture reduction and stabilization, may be a promising therapeutic approach for avian cases with similar injuries and bone anatomy. However, as this is a single case, this therapeutic modality deserves further application and study. Moreover, we suggest modifications in the bone marrow stem cell collection and therapy, which may be useful for future studies and application involving birds.

Use of Rodent Sedation Tests to Evaluate Midazolam and Flumazenil in Green Iguanas (Iguana iguana).

This study aimed to evaluate the applicability of rodent behavioral tests to assess the effects of midazolam and flumazenil in green iguanas. Four tests commonly used to assess sedation in rodents-the open field test, forced swim test, behavioral scale, and traction test-were conducted in 10 juveniles iguanas. The animals received midazolam (2 mg/kg IM) or 0.9% NaCl (0.4 mL/kg IM), and the tests were conducted between 0 and 300 min thereafter. To verify the effects of midazolam and flumazenil, the most informative tests from the evaluation stage and the limb withdrawal latency time (LWLT) were used. All 10 iguanas were tested under 4 conditions, as follows: MS, midazolam (2 mg/kg IM), followed 30 min later by 0.9% NaCl (0.4 mL/kg IM); FS, flumazenil (0.05 mg/kg IM), followed by 0.9% NaCl (0.4 mL/kg IM) 30 min later; MF, midazolam (2 mg/ kg IM), followed by flumazenil (0.05 mg/kg IM) 30 min later; and CON, 0.9% NaCl (0.4 mL/kg IM). The behavioral scale and the forced swim test showed the best detection of the onset, peak effect, and the differences between the sedated and control iguanas, with testing done between 15 and 240 min after drug administration. The sedative effect of midazolam began at 15 min and persisted through 180 min when assessed on the behavioral scale and 240 min when assessed by the forced swim test; flumazenil administration reversed the sedative effect. An increase in the LWLT was observed in the midazolam treatment groups between 15 and 30 min after drug administration. Flumazenil decreased LWLT between 15 and 180 min in the FS and at 60 min in the MF. In conclusion, the best methods to assess sedation in iguanas were the behavioral scale and the forced swim test. A dose of 2 mg/kg of midazolam was effective at inducing sedation in these juvenile iguanas, and this effect could be reversed by flumazenil.

Azaperone and xylazine: A pharmacological combination to facilitate captive deer management for red brocket deer (Mazama americana).

The care and management of deer in captivity is challenging, especially in the case of red brocket deer (Mazama americana), whose routine management using physical restraint is difficult. Our study evaluated the effects of azaperone and xylazine combination for immobilizing red brocket deer and allow for the standard capture and handling protocols (e.g., biological material, horn cutting, and trimming) to be conducted safely. Six adult, captive, red brocket deer received an intramuscular injection of either 1 mg/kg azaperone and 0.5 mg/kg xylazine (AX0.5) or 1 mg/kg azaperone and 1 mg/kg xylazine (AX1.0). Sedation latency, sternal recumbency, safe handling, and quality of the sedation were evaluated to provide an overview of how the immobilizing drugs affected managing the species in captivity. Additionally, heart rate, respiratory rate, mean arterial pressure, rectal temperature, pH, PaO2, PaCO2, SaO2, HCO3-, BE, Na+, K+ and serum lactate were also measured. The latency period of the animals in the AX0.5 group was greater than that of the animals in the AX1.0 group (7 ± 6.6 min vs. 5 ± 2.0 min), as was the time for them to assume sternal recumbency (12 ± 9.7 min vs. 6 ± 3.1 min). However, the time after the initial dose at which the animals could safely be handled (14 ± 4.5 min vs. 12 ± 5.2 min), and the time until the end of the safe handling period (75 ± 12.3 min vs. 85 ± 6.8 min) were similar for both groups. Animals in both groups showed physiological stability during all evaluations, but hypoxemia was observed in one animal in each group. We conclude that both drug combinations are safe and effective at sedating red brocket deer in captivity and suggest that the procedure be performed with oxygen supplementation to reduce the potential for hypoxia.

Evaluation of the applicability of musculoskeletal ultrasonography of the thoracolumbar and lumbar spine segment of healthy dogs / Avaliação da aplicabilidade da ultrassonografia musculoesquelética do segmento toracolombar e lombar da coluna vertebral de cães hígidos

Changes in the spine of dogs are usually detected in clinical and in surgical practice. Few studies exist on musculoskeletal ultrasound anatomy of the thoracolumbar and lumbar segments of the normal spine of dogs. This study aimed to compare the normal musculoskeletal ultrasound anatomy of the T10-S1 vertebral segments with images obtained with magnetic resonance imaging (MRI), computed tomography (CT), and anatomical structures, and to establish the ability to identify structures using these modalities. Ultrasound scans allowed visualization of the muscles of the region, articular processes, spinous process, interspinous ligament, and yellow ligament in the lumbosacral window. Computed tomography images provided better bone details, compared to ultrasound images. Low-field MRI allowed the identification of the same structures identified with ultrasound imaging, and allowed the identification of cerebrospinal fluid, transverse processes, and provided improved detail of the intervertebral discs and spinal cord. Knowledge of ultrasound anatomy of the region may allow the the identification of muscle and ligament injuries. Thus, in cities where CT and MRI are inaccessible, ultrasonography of the region could be a good alternative to identify possible changes not observable with radiographic examination or to complement radiographic examination.(AU)

Alterações na coluna vertebral de cães são comumente encontradas na rotina clínica e cirúrgica veterinária. Existem poucos estudos sobre a anatomia ultrassonográfica musculoesquelética do segmento toracolombar e lombar da coluna vertebral normal de cães. O objetivo deste trabalho foi comparar a anatomia ultrassonográfica musculoesquelética normal dos segmentos vertebrais T10-S1 com imagens obtidas pela ressonância magnética, tomografia computadorizada e peças anatômicas visando demonstrar a sua capacidade de identificação de estruturas. A varredura ultrassonográfica permitiu a visibilização da musculatura da região, processos articulares, processos espinhosos, ligamentos interespinhosos e ligamento amarelo na janela lombossacra. A tomografia computadorizada forneceu imagens com melhor detalhamento ósseo quando comparada ao exame ultrassonográfico. A ressonância magnética de baixo campo permitiu a identificação das mesmas estruturas que o exame ultrassonográfico acrescido da identificação do líquido cerebroespinal, processos transversos e melhor detalhamento dos discos intervertebrais e medula espinhal. Com o conhecimento da anatomia ultrassonográfica da região, acredita-se que lesões musculares e ligamentares possam ser identificadas. Vale salientar que em cidades onde a tomografia computadorizada e a ressonância magnética não estejam acessíveis a ultrassonografia da região pode ser uma boa alternativa para identificar possíveis alterações não visibilizadas ao exame radiográfico, ou complementá-lo.(AU)

Evaluation of sedative and antinociceptive effects of dexmedetomidine, midazolam and dexmedetomidine-midazolam in tegus (Salvator merianae).

OBJECTIVE: To evaluate dexmedetomidine, midazolam and dexmedetomidine-midazolam for sedation and antinociception in tegus. STUDY DESIGN: Prospective, crossover, randomized, blinded study. ANIMALS: Six healthy tegus (Salvator merianae) weighing 1.6±0.3 kg. METHODS: Tegus were administered intramuscularly saline (0.5 mL; CON), dexmedetomidine (0.2 mg kg-1; DX), midazolam (1 mg kg-1; MZ) and dexmedetomidine-midazolam (same doses; DM). Heart rate (HR) and respiratory frequency (fR) were recorded before treatment (baseline) and 15, 30 minutes, 1, 2, 3, 4, 6, 8, 12 and 24 hours after the treatments. Sedation scores were recorded according to resistance to manual restraint, posture and response to noxious stimulus, at baseline and 5, 10, 15, 30 minutes, 1, 2, 3, 4, 6, 8, 12 and 24 hours after the treatments. Antinociception was evaluated by measurement of latency of limb withdrawal reflex (LWR) to thermal stimulus, recorded at baseline and 15 minutes, 1, 2, 4, 8, 12 and 24 hours after the treatments. RESULTS: Lower HR (DX and DM) and fR (MZ, DX and DM) than CON were measured 15 minutes after the treatment and for up to 6 hours. Sedation was mild to moderate in MZ, deep in DM and absent in DX, although animals showed behavioral changes in DX, with increase in aggressiveness. Median (interquartile range) duration of sedation were 170 (50; 235) minutes in MZ and 230 (115; 235) minutes in DM. Recovery period was prolonged in both treatments, surpassing the duration of the experiment. Higher LWR than CON was detected from 15 minutes until 12 hours in DX and DM. CONCLUSIONS AND CLINICAL RELEVANCE: Midazolam provided sedation without antinociception, and dexmedetomidine provided antinociception without sedation. Drug combination increased the duration of sedation but not antinociception. Due to increased duration of sedation, reversal of effects with flumazenil and atipamezole should be considered after conclusion of clinical procedures.

Antinociceptive efficacy of intramuscular administration of morphine sulfate and butorphanol tartrate in tegus (Salvator merianae).

OBJECTIVE To evaluate the antinociceptive efficacy of IM morphine sulfate or butorphanol tartrate administration in tegus (Salvator merianae). ANIMALS 6 healthy juvenile (12- to 24-month-old) tegus (mean ± SD body weight, 1,484 ± 473 g). PROCEDURES In a crossover study design, tegus were randomly assigned to treatment order, with a minimum washout period of 15 days between treatments. Each of 5 treatments was administered IM in a forelimb: saline (0.9% NaCl) solution (0.5 mL), morphine sulfate (5 or 10 mg/kg), or butorphanol tartrate (5 or 10 mg/kg). A withdrawal latency test was used to evaluate antinociception, with a noxious thermal stimulus applied to the plantar surface of the hind limb before (0 hours; baseline) and 0.5, 1, 2, 3, 4, 6, 12, and 24 hours after each treatment. Observers were unaware of treatment received. RESULTS With saline solution, mean hind limb withdrawal latencies (interval to limb withdrawal from the thermal stimulus) remained constant, except at 12 hours. Tegus had higher than baseline mean withdrawal latencies between 0.5 and 1 hour and at 12 hours with morphine at 5 mg/kg and between 1 and 12 hours with morphine at 10 mg/kg. With butorphanol at 5 and 10 mg/kg, tegus maintained withdrawal responses similar to baseline at all assessment points. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that morphine, but not butorphanol, provided antinociception at 5 and 10 mg/kg in tegus as measured by thermal noxious stimulus testing. These data supported the hypothesis that µ-opioid (but not κ-opioid) receptor agonists provide antinociception in reptiles.

MOLECULAR DETECTION OF INFECTIOUS PATHOGENS OF THE UPPER RESPIRATORY TRACT IN CAPTIVE NONDOMESTIC FELIDS.

Upper respiratory tract disease is a complex infectious disease process with multiple pathogens involved. Identification of infectious agents in wild animals is of great importance for wildlife conservation. The aim of this study was to evaluate the molecular detection of feline herpesvirus type 1, feline calicivirus (FCV), Bordetella bronchiseptica , Chlamydophila felis , and Mycoplasma felis using ocular and nasal swabs in three species of captive nondomestic felids. Mycoplasma felis was detected in two ocular samples of Puma concolor and in one nasal sample of one Panthera onca . FCV was detected in association with M. felis in one P. concolor . The other pathogens tested were not detected. To the authors' knowledge, this is the first report of M. felis in nondomestic felids from Brazil.

Hyaluronidase administered with xylazine-tiletamine-zolazepam into adipose tissue shortens recovery from anesthesia in pigs.

OBJECTIVE: To evaluate the effect of hyaluronidase on uptake, duration and speed of elimination of xylazine-tiletamine-zolazepam administered in the subcutaneous fat over the dorsal lumbar region of swine. STUDY DESIGN: Blinded, randomized, crossover study. ANIMALS: Six healthy Landrace/Large White pigs weighing 132±24 kg (mean±standard deviation). METHODS: Animals were administered xylazine (1 mg kg-1) and tiletamine-zolazepam (8 mg kg-1) (control treatment, CON), or xylazine-tiletamine-zolazepam at the same doses with hyaluronidase (400 IU) (treatment HYA). The treatments were administered into the dorsal lumbar adipose tissue, 2.5-3.0 cm laterally from the spinous process of the second lumbar vertebra. The latency, anesthesia and recovery periods were measured. Heart rate, noninvasive systolic, diastolic, and mean arterial pressures, respiratory rate, hemoglobin oxygen saturation and rectal temperature were recorded every 10 minutes for up to 50 minutes. RESULTS: One animal in CON and one animal in HYA were responsive to stimulation and did not allow safe handling. No significant difference was found between treatments for latency (CON 11.3±5.9 minutes, HYA 7.4±5.1 minutes) and anesthesia (CON 53±53 minutes, HYA 49±38 minutes) periods. Recovery period was shorter in HYA (9±6 minutes) than in CON (32±16 minutes) (p < 0.05). Physiological variables were not significantly changed over time and were within accepted normal clinical limits for the species in both treatments. CONCLUSION AND CLINICAL RELEVANCE: Hyaluronidase (400 IU) administered into adipose tissue in pigs did not reduce the latency and duration of dissociative anesthesia, but was associated with faster recovery.

Inconsistency of allometric scaling for dissociative anesthesia of wild felids.

OBJECTIVE: To evaluate allometric scaling for ketamine-xylazine (KX) anesthesia in wild felids using domestic cats for reference. STUDY DESIGN: Prospective single-phase non-blinded study. ANIMALS: Six domestic cats and 13 wild felids (five Leopardus pardalis, five Puma concolor, one Panthera onca and two Panthera leo). METHODS: Six domestic cats (4.1 ± 0.8 kg, REF1) were anesthetized by intramuscular administration of ketamine (15 mg kg(-1) ) and xylazine (1 mg kg(-1) ). Wild cats were divided into three groups based on body weight: 12.9 ± 2.4 kg (G1; n = 7), 43.0 ± 15.7 kg (G2; n = 4) and 126.0 ± 7.8 kg (G3; n = 2). Ketamine and xylazine doses were calculated based on allometric scaling of the basal metabolic rate (BMR = 70 × body mass(0.75) ). Afterwards, the six domestic cats were administered mean KX doses calculated for G1 and G2 (REF2). The heart rate, systolic arterial pressure, respiratory frequency, pH, the venous partial pressure of carbon dioxide, bicarbonate and lactate concentrations were recorded for up to 60 minutes. RESULTS: Additional doses were required in 12 out of the 13 wild cats. Anesthesia was not achieved in G3. Latency periods in wild felids were longer than REF1 and REF2. Anesthesia duration in REF1 was longer than that in the other groups. Recovery from anesthesia in REF1 and REF2 was longer than G1 and G2. Physiological variables remained within the range limits for the species. G1 baseline lactate concentration was higher than in the other groups. CONCLUSION AND CLINICAL RELEVANCE: KX anesthesia established by allometric scaling of BMR from doses administered to domestic cats did not predict reliable anesthetic doses for wild cats. Dose rates calculated with this method must not be applied to these species.

Lactated Ringer's solution or 0.9 por cento sodium chloride as fluid therapy in pigeons (Columba livia) submitted to humerus osteosynthesis / Fluidoterapia com Ringer lactato ou cloreto de sódio 0.9 percent em pombos (Columbia livia) submetidos à osteossíntese de úmero

The study aimed to compare the effects of intraosseous infusion of lactated Ringer's and 0.9% sodium chloride solutions on the electrolytes and acid-base balance in pigeons submitted to humerus osteosynthesis. Eighteen pigeons were undergoing to isoflurane anesthesia by an avalvular circuit system. They were randomly assigned into two groups (n=9) receiving lactated Ringer's solution (LR) or 0.9% sodium chloride (SC), in a continuous infusion rate of 20mL/kg/h, by using an intraosseous catheter into the tibiotarsus during 60-minute anesthetic procedure. Heart rate (HR), and respiratory rate (RR) were measured every 10 min. Venous blood samples were collected at 0, 30 and 60 minutes to analyze blood pH, PvCO2, HCO3 -, Na+ and K+. Blood gases and electrolytes showed respiratory acidosis in both groups during induction, under physical restraint. This acidosis was evidenced by a decrease of pH since 0 min, associated with a compensatory response, observed by increasing of HCO3 - concentration, at 30 and 60 min. It was not observed any changes on Na+ and K+ serum concentrations. According to the results, there is no reason for choosing one of the two solutions, and it could be concluded that both fluid therapy solutions do not promote any impact on acid-base balance and electrolyte concentrations in pigeons submitted to humerus osteosynthesis...

O presente estudo avaliou os efeitos da infusão das soluções de Ringer lactato ou cloreto de sódio 0,9%, no equilíbrio ácido-base e hidroeletrolítico de pombos submetidos à osteossíntese de úmero. Foram utilizados 18 animais, os quais foram submetidos à anestesia por isofluorano, e mantidos em circuito avalvular durante o período anestésico (60 min). Os animais foram distribuídos aleatoriamente em dois grupos (n=9) recebendo Ringer lactato (LR) ou cloreto de sódio 0,9% (SC), administradas na taxa de 20mL/kg/h pela via intraóssea (tibiotarso). Foram monitoradas as frequências cardíaca e respiratória a cada 10 minutos e colhidas amostras sanguíneas venosas aos 0, 30 e 60 min de anestesia, obtendo-se a partir destas, valores de pH sanguíneo, bicarbonato (HCO3), pressão venosa de CO2 (PvCO2), sódio (Na+) e potássio (K+). Os valores referentes ao equilíbrio ácido-base indicam que houve acidose respiratória em ambos os grupos, a qual foi decorrente do processo de indução sob contenção física, caracterizada por diminuição no pH desde o 0 min, associado ao aumento compensatório nos valores de HCO3 -, nos momentos 30 e 60 min. No entanto, no que se refere aos valores obtidos de Na+ e K+ séricos, durante a infusão de ambos os fluidos, não foram observadas alterações que justifiquem a predileção por alguma destas soluções. Diante destes resultados conclui-se que a escolha entre uma das soluções avaliadas não promoveu impacto sob o equilíbrio ácido-base e hidroeletrolítico de pombos submetidos a osteossíntese de úmero...

Physiological and analgesic effects of continuous-rate infusion of morphine, butorphanol, tramadol or methadone in horses with lipopolysaccharide (LPS)-induced carpal synovitis.

BACKGROUND: Continuous-rate infusion (CRI) of drugs results in more stable plasma drug concentrations than administration of intermittent boluses, thus providing greater stability of physiological parameters. The aim of this study was to evaluate the physiologic and analgesic effects of the administration of morphine, butorphanol, tramadol or methadone by CRI in horses with induced synovitis of the radiocarpal joint. RESULTS: Increased values of cardiorespiratory parameters and body temperature were observed in all groups after initiation of opioid administration, and these increases were sustained throughout the CRI period. Morphine, butorphanol and methadone each caused a reduction in gut sounds, and this effect was greatest in animals that received morphine. Administration of morphine or methadone reduced the degree of lameness after the end of intravenous infusion. Administration of tramadol did not alter the degree of lameness in the animals. CONCLUSIONS: CRI of morphine or methadone, but not butorphanol or tramadol, provided analgesia in horses with carpal synovitis. All of these opioids increased cardiovascular and respiratory parameters and reduced gut sounds during CRI.

Effect of tepoxalin on renal function and hepatic enzymes in dogs exposed to hypotension with isoflurane.

OBJECTIVE: To evaluate the possible renal and hepatic toxicity of tepoxalin in dogs exposed to hypotension during isoflurane anesthesia. STUDY DESIGN: Prospective, randomized experimental study. ANIMALS: Twenty adult mixed-breed dogs, weighing 18.8 ± 2.8 kg. METHODS: The animals received 10 mg kg(-1) tepoxalin orally 2 hours before the anesthetic procedure (PRE; n = 6), or 30 minutes after anesthesia (POST; n = 6), along with a control group (CON; n = 8), which were only anesthetized. The PRE and POST groups also received the same dose of tepoxalin for 5 days post-procedure. All dogs were anesthetized with propofol and maintained with isoflurane and the end-tidal isoflurane (Fe'Iso) was increased until mean arterial pressure decreased to 50-60 mmHg. These pressures were maintained for 60 minutes. Heart rate, arterial pressures and Fe'Iso were recorded at 0, 10 and every 10 minutes up to 60 minutes of hypotension. Blood gases, pH, electrolytes and bleeding time were analyzed before and at 30 and 60 minutes of hypotension. Renal and hepatic changes were quantified by serum and urinary biochemistry and creatinine clearance. RESULTS: Serum concentrations of alanine amino transferase (ALT), alkaline phosphatase (ALP) and γ-glutamyl transferase (GGT), blood urea nitrogen (BUN) and creatinine (Cr), and urinary output, urinary Cr, Cr clearance, and GGT:Cr ratio remained stable throughout the evaluations. During the anesthetic procedure there were no important variations in the physiological parameters. No side effects were observed in any of the groups. CONCLUSIONS AND CLINICAL RELEVANCE: Tepoxalin did not cause significant effects on renal function or cause hepatic injury in healthy dogs exposed to hypotension with isoflurane, when administered pre- or postanesthetic and continued for five consecutive days.

Evaluation of analgesic and physiologic effects of epidural morphine administered at a thoracic or lumbar level in dogs undergoing thoracotomy.

OBJECTIVE: To evaluate the analgesic and physiological effects of epidural morphine administered at the sixth and seventh lumbar or the fifth and sixth thoracic vertebrae in dogs undergoing thoracotomy. STUDY DESIGN: Prospective, randomized, blinded trial. ANIMALS: Fourteen mixed-breed dogs, weighing 8.6 ± 1.4 kg. METHODS: The animals received acepromazine (0.1 mg kg⁻¹) IM and anesthesia was induced with propofol (4 mg kg)⁻¹ IV. The lumbosacral space was punctured and an epidural catheter was inserted up to the region between the sixth and seventh lumbar vertebrae (L, n = 6) or up to the fifth or sixth intercostal space (T, n = 8). The dogs were allowed to recover and after radiographic confirmation of correct catheter position, anesthesia was reinduced with propofol IV and maintained with 1.7% isoflurane. Following stabilization of monitored parameters, animals received morphine (0.1 mg kg⁻¹) diluted in 0.9% NaCl to a final volume of 0.25 mL kg⁻¹ via the epidural catheter, and after 40 minutes, thoracotomy was initiated. Heart rate and rhythm, systolic, mean and diastolic arterial pressures, respiratory rate, arterial hemoglobin oxygen saturation, partial pressure of expired CO2 and body temperature were measured immediately before the epidural administration of morphine (0 minute) and every 10 minutes during the anesthetic period. The Melbourne pain scale and the visual analog scale were used to assess postoperative pain. The evaluation began 3 hours after the epidural administration of morphine and occurred each hour until rescue analgesia. RESULTS: There were no important variations in the physiological parameters during the anesthetic period. The post-operative analgesic period differed between the groups, being longer in T (9.9 01.6 hours) compared with L (5.8 ± 0.8 hours). CONCLUSIONS: The use of morphine, at a volume of 0.25 mL kg 0.1, administered epidurally over the thoracic vertebrae provided longer lasting analgesia than when deposited over the lumbar vertebrae.

Cardiorespiratory and antinociceptive effects of two different doses of lidocaine administered to horses during a constant intravenous infusion of xylazine and ketamine.

BACKGROUND: This study investigated the antinociceptive effects of a constant rate infusion (CRI) of lidocaine during xylazine and ketamine anesthesia in horses and aimed to correlate these effects with cardiorespiratory variables, bispectral index (BIS) and plasma lidocaine concentrations. Six adult crossbred mares weighing 320-400 kg were anesthetized on three different occasions. Sedation was performed with xylazine (0.75 mg/kg IV) and anesthetic induction with guaifenesin (75 mg/kg IV) and ketamine (2 mg/kg IV). Anesthesia was maintained with 37.5 µg/kg/min of xylazine and 87.5 µg/kg/min of ketamine both administered intravenously for 75 min. The three treatments consisted of: lidocaine (loading dose: 5 mg/kg, CRI: 100 µg/kg/min; THL); lidocaine (loading dose: 2.5 mg/kg; CRI: 50 µg/kg/min: TLL); and saline (TS); all given 15 min after induction and maintained for 1 h. Antinociception was measured by response to electrical stimulation and bispectral index (BIS) was recorded during anesthesia. Parametric and non-parametric data were compared using ANOVA followed by Student-Newman-Keuls and Friedman tests, respectively. RESULTS: Plasma lidocaine concentrations peaked at the end of lidocaine loading dose and was greater in THL (9.61 ± 2.75 µg/mL) vs TLL (4.50 ± 3.34 µg/mL). Electrical noxious stimulation caused purposeful movement in all horses from TS, but no response in THL. The BIS was decreased in THL only and was less when compared to the other treatments throughout anesthesia. Blood pressure, PaO2 and PaCO2 increased and heart rate (HR), respiratory rate (RR), pH, total plasma protein and temperature decreased during anesthesia in all treatments. PaCO2 and HR were greater and RR and pH less in THL compared to TLL and TS at 30 min during anesthesia. All recoveries were considered excellent. Time to standing was longer after THL (60 ± 20 min) than following TLL and TS (32 ± 17 and 30 ± 15 min, respectively). CONCLUSIONS: At the highest dose administered (THL) lidocaine CRI during xylazine/ketamine anesthesia decreased BIS and motor response to noxious stimulation, and prolonged recovery time without significant added cardiorespiratory depression.

Acid-base and biochemical stabilization and quality of recovery in male cats with urethral obstruction and anesthetized with propofol or a combination of ketamine and diazepam.

This study compared acid-base and biochemical changes and quality of recovery in male cats with experimentally induced urethral obstruction and anesthetized with either propofol or a combination of ketamine and diazepam for urethral catheterization. Ten male cats with urethral obstruction were enrolled for urethral catheterization and anesthetized with either ketamine-diazepam (KD) or propofol (P). Lactated Ringer's solution was administered by intravenous (IV) beginning 15 min before and continuing for 48 h after relief of urethral obstruction. Quality of recovery and time to standing were evaluated. The urethral catheter was maintained to measure urinary output. Hematocrit (Hct), total plasma protein (TPP), albumin, total protein (TP), blood urea nitrogen (BUN), creatinine, pH, bicarbonate (HCO3-), chloride, base excess, anion gap, sodium, potassium, and partial pressure of carbon dioxide in mixed venous blood (pvCO2) were measured before urethral obstruction, at start of fluid therapy (0 h), and at subsequent intervals. The quality of recovery and time to standing were respectively 4 and 75 min in the KD group and 5 and 16 min in the P group. The blood urea nitrogen values were increased at 0, 2, and 8 h in both groups. Serum creatinine increased at 0 and 2 h in cats administered KD and at 0, 2, and 8 h in cats receiving P, although the values were above the reference range in both groups until 8 h. Acidosis occurred for up to 2 h in both groups. Acid-base and biochemical stabilization were similar in cats anesthetized with propofol or with ketamine-diazepam. Cats that received propofol recovered much faster, but the ketamine-diazepam combination was shown to be more advantageous when treating uncooperative cats as it can be administered by intramuscular (IM) injection.