Determination of the minimum alveolar concentration (MAC) of isoflurane and sevoflurane in Callithrix penicillatac

Background: The minimum alveolar concentration (MAC) is a measure of quantitative anesthetic potency and has become the standard index for the evaluation and comparison of volatile anesthetics, in addition to guiding dose administration. Black-tufted marmosets (Callithrix penicillata) are primates present in the clinical and surgical routine of veterinary hospitals, as well as experimental models, especially in neuroscience. Few studies have evaluated the potency of the main volatile anesthetics in this species. This study aimed to determine the MAC of isoflurane and sevoflurane in C. penicillata using the up-and-down method and to evaluate the effects of these drugs on the quality of anesthetic induction, maintenance, and recovery. Materials, Methods & Results: Twenty-four animals of undetermined age were used. All marmosets were healthy according to hematological and physical evaluation. The animals were randomly divided into 2 groups: ISOMAC and SEVOMAC. Each animal was induced to general anesthesia in an anesthetic box with oxygen (5 L/min) and sevoflurane at 7% in the SEVOMAC group or isoflurane at 5% in the ISOMAC. Upon reaching lateral decubitus, orotracheal intubation was performed. General anesthesia was maintained with isoflurane or sevoflurane diluted in oxygen (0.8 L/min) using a non-rebreathing delivery system under spontaneous ventilation. As defined in the pilot study, the first animal from ISOMAC started the maintenance of anesthesia with 2.6% isoflurane, while the first animal in SEVOMAC received 4% sevoflurane. After finishing the instrumentation to assess heart rate, respiratory rate, systolic blood pressure, pulse oximeter oxygen saturation, end-tidal carbon dioxide concentration, and rectal temperature, a 15-min wait to reach anesthetic equilibrium was allowed, and then an electrical noxious stimulation (50 mA and 50 Hz) was performed on the lateral aspect of the thigh (a faradic current of 3 consecutive single stimuli, followed by 2 continuous stimuli). The animals' responses to the electrical stimulus were observed. The presence of a positive response (gross movement of the limbs, head, or vocalization) or a negative response (absence of gross movements) determined the increase or reduction, respectively, of the inhalation anesthetic concentration by 10% in the subsequent marmoset. The quality of anesthetic induction and recovery from anesthesia was evaluated using a scale that measured the intensity of agitation, coughing, nausea, and vomiting. Physiological variables were recorded before (M0) and after (M1) applying the nociceptive stimulus. Isoflurane and sevoflurane MAC values in C. penicillata were 2.29 ± 0.10% and 3.93 ± 0.61 % respectively. Physiological parameters, quality of anesthetic induction and recovery did not differ significantly between groups. However, isoflurane caused irritation of the airway and ocular mucous membranes, more coughing episodes, and tearing at induction. There was no difference between groups for time to extubation and recovery time to regain sternal position. Discussion: Previous studies in primates found lower MAC values for both anesthetics, except for Lemur catta. Those findings may be explained by the use of different nociceptive stimuli and the MAC determination method employed, although no differences in MAC values have been described between bracketing or up-and-down methods in human primates and dogs. It is unlikely that the stimulus and technique alone are the determining factors for the high concentration of isoflurane and sevoflurane observed in the present study since MAC was high with both halogenates, indicating that dose extrapolation from other species can lead to the wrong anesthetic dosage.

Influence on clinical biochemistry values of black-tufted marmosets (Callithrix penicillata) anesthetized with isoflurane or sevoflurane / Influência sobre valores de bioquímica clínica de saguis-de-tufo-preto (Callithrix penicillata) anestesiados com isoflurano ou sevoflurano

The objective of this study was to evaluate the clinical biochemistry behavior of Black-Tufted Marmosets (Callithrix penicillatta) submitted to blood collection without sedation and after general anesthesia with anesthetics isoflurane or sevoflurane. Blood collections were performed on (M1) day before anesthesia by physical restraint, and (M2) after anesthesia. There were four groups: Isoflurane (GI) and Sevoflurane (GS) using an anesthetic box. GIM: isoflurane induction with mask for a shorter period. Control group (GP): physical restraint in both moments. Plasma was separated and frozen to measure clinic biochemistry values. Urea was higher at M2 in groups GI and GP. AST was higher in M2 in GI, GS, and GP and only GI showed an increase in CK in M2. Glucose was higher in M1 in the GI, GS, and GP groups and fructosamine was higher in M2 in the GI. Stress caused by physical restraint can cause biochemical changes and these must be considered when interpreting the exams. Both the inhalational anesthetic isoflurane and sevoflurane did not cause clinically significant changes in clinical biochemistry results.

O objetivo desse estudo foi avaliar o comportamento da bioquímica clínica de saguis-do-tufo-preto (Callithrix penicillatta) submetidos à coleta sanguínea sem sedação e após anestesia geral, com os anestésicos isoflurano ou sevoflurano. As coletas de sangue foram realizadas: (M1) dia antes da anestesia por contenção física e (M2) após anestesia. Foram definidos quatro grupos: isoflurano (GI) e sevoflurano (GS), utilizando caixa anestésica; GIM: indução com isoflurano com máscara por um período menor; grupo controle (GCF): contenção física em ambos os momentos. O plasma com EDTA foi separado e congelado para realizar dosagem da bioquímica clínica. A ureia foi maior no M2 nos grupos GI e GCF. A AST foi maior no M2 nos GI, GS e GCF e somente o GI apresentou aumento de CK no M2. A glicose foi maior no M1 nos grupos GI, GS e GCF, e a frutosamina foi maior no M2 no GI. O estresse causado pela contenção física pode causar alterações bioquímicas e essas devem ser levadas em consideração na interpretação dos exames. Tanto o anestésico inalatório isoflurano quanto o sevoflurano não causaram alterações clinicamente significantes nos resultados da bioquímica clínica.

Assessment of thermal response, cardiorespiratory parameters and post-operative analgesia in dogs undergoing ovariohysterectomy with different combinations of epidural analgesia and isoflurane

This study aimed to evaluate the thermal response of the eyelids and lacrimal gland of the left eye (LETG) through infrared thermography (IRT), cardiorespiratory parameters, and their association with nociception and pain in bitches undergoing elective ovariohysterectomy (OVH) anesthetized with isoflurane and epidural analgesia. Twenty-one healthy bitches of different breeds were randomized into three groups receiving epidural blocks: GL (n=7), lidocaine (2 mg Kg-1 ); GLF (n=7), lidocaine (2 mg Kg-1 ) and fentanyl (3 µg Kg-1 ); and GLM (n=7), lidocaine (2 mg Kg-1 ) with morphine (0.1 mg Kg-1 ). IRT and cardiorespiratory parameters were evaluated at baseline (Ebasal), thirty minutes before anesthetic premedication, and at different surgical events: first incision (EInc), ligature and section of the left (ELoV), and right (ERoV) ovarian pedicle, ligature, and re-section of the cervix (EUt), and skin suture (ESut). The assessment of acute pain in the immediate post-operative period was registered at E1h, E2h, and E3h using IRT, the Dynamic Interactive Visual Analogic Scale (DIVAS), and the University of Melbourne Pain Scale (UMPS) scales. The results showed a statistically significant decrease in the lower eyelid surface temperature (LELT) during EInc for GL (32.9°C ± 0.62), in comparison to GLF (34.2°C ± 0.62) and GLM (35.3°C ± 0.62) (P = 0.006). Regarding LETG, a significant increase (P = 0.03) in the IRT of Ebasal (36.8°C ± 0.63) and EInc (36.1°C ± 0.63) for GLM was observed in comparison to the thermographic values for both perioperative events and groups. The GLM showed a significant decrease in IRT values of ERoV at E3h in the upper and lower eyelids (P = 0.03 and P = 0.01, respectively). A progressive and significant reduction of the IRT values of LETG was also recorded in GLM, with differences in ERoV (35.2 °C ± 0.63) (P = 0.02) and E3h (35.3 °C ± 0.63) (P = 0.01). The cardiovascular parameters (SAP, DAP, and MAP) did not differ between treatments, but in GL, there was a significant difference (P = 0.01) during EInc and ESut, compared to Ebasal. In the body temperature, EInc and ESut gradually decreased in all treatment groups (P = 0.01). In conclusion, hemodynamic and cardiorespiratory stability was associated with IRT readings and the absence of nociception. Changes in superficial temperature in the immediate post-operative period were lessened using isoflurane and epidural analgesia of lidocaine alone or in combination with pure opioids. These findings were clinically validated to the DIVAS and UMPS acute pain assessment scales.

Bezold-Jarisch reflex induced by dopamine during isoflurane anesthesia in small dogs

Background: Unlike other major reflexes contributing to hemodynamic homeostasis, the Bezold-Jarisch reflex (BJR)paradoxically decreases heart rate (HR) and mean arterial pressure (MAP) despite hypotension. In the veterinary field,there are few reported cases of BJR induced by dopamine, which is often used to manage hypotension. Herein, 2 casesinvolving small dogs exhibiting BJR due to dopamine infusion during general anesthesia are described.Cases: Case 1: A 7-year-old, 7 kg, mongrel was referred for external skeletal fixator removal. The patient was premedicatedwith 0.3 mg/kg midazolam and 0.2 mg/kg butorphanol intravenously (IV). General anesthesia was induced with 6 mg/kgpropofol and maintained with 1.6% isoflurane in oxygen. The patient was given 5 mL/kg/h of Hartmann’s solution IV. Therespiratory rate (RR) was set to 9 breaths/min with a ventilator. The HR and MAP values were initially 120 bpm and 76mmHg and gradually decreased to 70 bpm and 40 mmHg, respectively. The end-tidal CO2 partial pressure (ETCO2) was 39mmHg, and the patient was administered 2.5 μg/kg glycopyrrolate IV. Then, 5 μg/kg/min dopamine was administered IVsince the MAP did not improve. The HR, MAP, and ETCO2 increased to 113 bpm, 72 mmHg, and 47 mmHg, respectively.Subsequently, HR and MAP dramatically decreased to 50 bpm and 43 mmHg, respectively. A second-degree atrioventricularblock was detected, prompting dopamine infusion discontinuation, and 2.5 μg/kg glycopyrrolate was again administeredIV. Within 5 min, HR and MAP values normalized, and postoperative patient recovery was typical. Case 2: A 2-year-old,8.6 kg, mongrel underwent surgery to correct a medial luxating patella of the right leg. The patient was premedicated with0.3 mg/kg midazolam and 0.2 mg/kg butorphanol IV. Anesthesia was induced with 4 mg/kg propofol IV and maintained...

Bezold-Jarisch reflex induced by dopamine during isoflurane anesthesia in small dogs

Background: Unlike other major reflexes contributing to hemodynamic homeostasis, the Bezold-Jarisch reflex (BJR)paradoxically decreases heart rate (HR) and mean arterial pressure (MAP) despite hypotension. In the veterinary field,there are few reported cases of BJR induced by dopamine, which is often used to manage hypotension. Herein, 2 casesinvolving small dogs exhibiting BJR due to dopamine infusion during general anesthesia are described.Cases: Case 1: A 7-year-old, 7 kg, mongrel was referred for external skeletal fixator removal. The patient was premedicatedwith 0.3 mg/kg midazolam and 0.2 mg/kg butorphanol intravenously (IV). General anesthesia was induced with 6 mg/kgpropofol and maintained with 1.6% isoflurane in oxygen. The patient was given 5 mL/kg/h of Hartmanns solution IV. Therespiratory rate (RR) was set to 9 breaths/min with a ventilator. The HR and MAP values were initially 120 bpm and 76mmHg and gradually decreased to 70 bpm and 40 mmHg, respectively. The end-tidal CO2 partial pressure (ETCO2) was 39mmHg, and the patient was administered 2.5 μg/kg glycopyrrolate IV. Then, 5 μg/kg/min dopamine was administered IVsince the MAP did not improve. The HR, MAP, and ETCO2 increased to 113 bpm, 72 mmHg, and 47 mmHg, respectively.Subsequently, HR and MAP dramatically decreased to 50 bpm and 43 mmHg, respectively. A second-degree atrioventricularblock was detected, prompting dopamine infusion discontinuation, and 2.5 μg/kg glycopyrrolate was again administeredIV. Within 5 min, HR and MAP values normalized, and postoperative patient recovery was typical. Case 2: A 2-year-old,8.6 kg, mongrel underwent surgery to correct a medial luxating patella of the right leg. The patient was premedicated with0.3 mg/kg midazolam and 0.2 mg/kg butorphanol IV. Anesthesia was induced with 4 mg/kg propofol IV and maintained...(AU)

Establishing an anesthetic protocol for refinement of intracerebral inoculation procedure

Mouse inoculation test (MIT) is a technique widely used for rabies diagnosis and must be liable to refinement due to animal welfare. The present study aims to compare five different anesthetic associations to stablish a protocol to improve the MIT procedure suitable for animal welfare and safe for a routine of viral isolation in newly weaned mice (3 weeks of age). 80 Swiss-Webster mice (Mus musculus) - 40 females and 40 males, 3-week-old, weight ranging from 11 to 14 grams ­ were used to conduct all procedures. Five anesthetic associations were tested: KX (Ketamine 100 mg/kg and Xylazine 10 mg/kg), KXA (Ketamine 80 mg/kg, Xylazine 5 mg/kg, and Acepromazine 1 mg/kg), KXT (Ketamine 80 mg/kg, Xylazine 5 mg/kg, and Tramadol 5 mg/kg), KXAT (Ketamine 100 mg/kg, Xylazine 10 mg/kg, Acepromazine 2 mg/kg and Tramadol 5 mg/kg) and ATI (Acepromazine 1 mg/kg + Tramadol 5 mg/kg + Isoflurane 5% - 0.5 L/min for induction and 2.5% - 0.5L/min for maintenance). Injectable anesthesia was administered intraperitoneally. We monitored the respiratory rate and body temperature. Response to anesthesia was evaluated according to the induction, surgical anesthesia, and recovery periods. The KXAT and ATI protocols induced surgical anesthesia, with the ATI protocol being the most appropriate and safe to perform the MIT procedure with 100% efficiency, absence of mortality, and rapid recovery of respiratory rate and temperature in the period after the procedure.

Histomorphometric comparison of the corpus cavernosum of rats submitted to euthanasia with ketamine and xylazine or isoflurane

ABSTRACT Purpose: To compare the penile histoarchitecture of rats euthanized with isoflurane or with ketamine and xylazine. Methods: Fourteen male rats were divided into two groups: ISO, with animals euthanized with isoflurane; and K+X, with animals euthanized with ketamine (150 mg/kg) associated with xylazine (15 mg/kg). Immediately after the death, the penises were dissected, fixed in a 4% buffered formalin solution, and processed for histomorphometric analysis. The surface densities (Sv) of the corpus cavernosum structures (connective tissue, smooth muscle, sinusoidal space, and elastic fibers) were evaluated using Image J software. The distribution of collagen types I and III was qualitatively assessed. Statistical analyses were performed using the Student's t test for data comparison, considering it statistically significant when p < 0.05. Results: Regarding the Sv of connective tissue, smooth muscle and sinusoidal space, there were no differences between animals in both groups. On the other hand, the animals euthanized with the association of ketamine and xylazine showed the Sv of elastic fibers 24.8% higher in relation to animals euthanized with isoflurane. Conclusions: The euthanasia method affected one of the morphological parameters of the rat penises. The choice of euthanasia method must be standardized to reduce bias and to obtain reliable and reproducible results.

Hypersensitivity in chicken (Gallus gallus domesticus) due to the association of lidocaine and bupivacaine in neural-guided femoral and sciatic nerve block

Background: Osteosyntheses, orthopedic surgeries that cause highly painful stimulation, are increasingly common inveterinary medicine. Epidural anesthesia is used to provide intraoperative and postoperative analgesia in mammals undergoing pelvic limb surgery. In birds, the synsacrum, the bone originating from the fusion of the lumbar and sacral vertebrae,makes this route inapplicable, thus peripheral nerve block is an easier option in this species. This report describes a caseof local hypersensitivity following the association of lidocaine and bupivacaine in anesthetic blocks of the femoral andsciatic nerves in chickens (Gallus gallus domesticus).Case: A study was conducted in chickens evaluating the effectiveness of anesthetic sciatic and femoral nerve blocks, guidedby a neural stimulator. Thirty-two 42-day-old male chickens of the species Gallus gallus domesticus, double breasted,weighing 1.86 ± 0.5 kg, were randomly divided into four groups: control (CG), lidocaine (LG), bupivacaine (BC) andthe association of lidocaine and bupivacaine (LBG). The doses used were 4 mg/kg of 2% lidocaine and 2 mg/kg of 0.5%bupivacaine, without vasoconstrictor. For CG, 0.9% NaCl solution was used, respecting the total volume of 1 mL/kg.Only one bird from the LBG showed side effects, presenting sensory and motor loss for 24 h after the administration ofthese drugs, before euthanasia was performed using anesthetic induction with isoflurane through a face mask, followedby the intravenous administration of propofol and then potassium chloride. The chicken was submitted to a necropsy andmacroscopically, soft, irregular, brownish lesions with a grayish focus were observed...

Hypersensitivity in chicken (Gallus gallus domesticus) due to the association of lidocaine and bupivacaine in neural-guided femoral and sciatic nerve block

Background: Osteosyntheses, orthopedic surgeries that cause highly painful stimulation, are increasingly common inveterinary medicine. Epidural anesthesia is used to provide intraoperative and postoperative analgesia in mammals undergoing pelvic limb surgery. In birds, the synsacrum, the bone originating from the fusion of the lumbar and sacral vertebrae,makes this route inapplicable, thus peripheral nerve block is an easier option in this species. This report describes a caseof local hypersensitivity following the association of lidocaine and bupivacaine in anesthetic blocks of the femoral andsciatic nerves in chickens (Gallus gallus domesticus).Case: A study was conducted in chickens evaluating the effectiveness of anesthetic sciatic and femoral nerve blocks, guidedby a neural stimulator. Thirty-two 42-day-old male chickens of the species Gallus gallus domesticus, double breasted,weighing 1.86 ± 0.5 kg, were randomly divided into four groups: control (CG), lidocaine (LG), bupivacaine (BC) andthe association of lidocaine and bupivacaine (LBG). The doses used were 4 mg/kg of 2% lidocaine and 2 mg/kg of 0.5%bupivacaine, without vasoconstrictor. For CG, 0.9% NaCl solution was used, respecting the total volume of 1 mL/kg.Only one bird from the LBG showed side effects, presenting sensory and motor loss for 24 h after the administration ofthese drugs, before euthanasia was performed using anesthetic induction with isoflurane through a face mask, followedby the intravenous administration of propofol and then potassium chloride. The chicken was submitted to a necropsy andmacroscopically, soft, irregular, brownish lesions with a grayish focus were observed...(AU)

Anesthesia for osteosynthesis of femur in a cane toad (Rhinella marina)

Background: The taxonomic order Anura is composed of frogs and toads, with approximately 6,000 species worldwide, of which 900 species are found in Brazil. Rhinella marina, popularly known as "sapo-cururu," is the most commonly found frog in Brazil. Although most of these animals are found in research laboratories and zoos, they are increasingly being reared as pets. Therefore, sedation or anesthesia is often necessary for these animals to facilitate medical care, complementary examinations, or surgical procedures. However, there are only a few reports of anesthesia in frogs. Therefore, the present report aimed to describe the anesthetic protocol for femoral osteosynthetic surgery in an adult cane toad. Case: An adult cane toad presented with a history of difficulty in moving the left hindlimb and loss of limb movements. Radiography showed a simple, complete, transverse, and closed average shaft of the left femur and bone shaft fracture deviation. The animal was referred for an osteosynthetic surgery to stabilize the fracture. Animal restraint was performed using humidified gloves on the operating table. As premedication, ketamine, meloxicam, and morphine were administered, and general anesthesia was induced with isoflurane through a face mask. The anesthesia was maintained with isoflurane through a drip on the animal's back for cutaneous absorption. Lidocaine (2%) anesthetic gel was applied on the incision line to complement the somatic analgesia. The fracture was fixed using an intramedullary Kirschner pin. The heart rate was measured based on the beep of the arterial pulse using a Doppler ultrasonic device, respiratory rate was recorded by visual observation of the animal's respiratory motion, and body temperature was assessed using an esophageal digital thermometer - all of these remained stable during the procedure. Morphine, enrofloxacin, and meloxicam were administered postoperatively. The animal was discharged from the hospital seven days after the surgery, and 14 days later, the animal was deemed clinically stable with favorable wound healing. Discussion: Toads use their skin to breathe and maintain osmotic balance. Therefore, their skin is extremely sensitive to dehydration, requiring constant wetting. General anesthesia in amphibians is recommended for prolonged and painful procedures, as in the present case. Different anesthetics, analgesics, and associated drugs may be used. Ketamine is often used for chemical restraint in amphibians, and the induction and recovery times may vary due to sensitivity and drug resistance. Inhalational anesthesia with isoflurane may also be effective; in the present case, the anesthetic was administered using a mask placed on the frog's skin, without any irritation. Analgesia is essential for any animal, and amphibians have opioid receptors that may be used as targets of non-steroidal anti-inflammatory agents. As indicated for all species, the animal was monitored throughout the procedure. Assessment of heartbeat is the simplest way to monitor anesthesia using Doppler (on the heart or throat); in the present case, was placed on the axillary artery for clear auscultation. In addition, other parameters, such as temperature and primary respiratory movements, were monitored. Anesthetic recovery can take hours or even days, whereas excretion depends on the metabolic rate of each animal. In the present case, recovery was observed 4 h after completion of the procedure, using fresh water on the animal's body to accelerate recovery, as indicated in the literature. This case demonstrated that anesthesia and medications used for anesthesia induction, maintenance, and recovery are safe in toads. For cane toads, during femoral osteosynthesis, this anesthetic procedure has never been described previously in the literature. Finally, such information can aid veterinarians in performing safe and adequate analgesic and anesthetic procedures for the wellbeing of animals.

Bloqueio do plano transverso do abdômen guiado por ultrassom em felino submetido a mastectomia regional / Blocking of the abdomen transverse plan guided by ultrasound in feline submitted to regional mastectomy

Os bloqueios locorregionais vêm sendo cada vez mais utilizados na medicina veterinária. O bloqueio do plano transverso do abdômen (TAP Block) é uma técnica de anestesia locorregional, faz parte da estratégia de analgesia multimodal, capaz de promover anestesia e analgesia em regiões de pele, musculatura e peritônio parietal. O objetivo deste trabalho é relatar o bloqueio do plano transverso em um felino macho de dois anos de idade submetido a mastectomia regional. Foram feitos dois pontos de bloqueio do espaço TAP guiado por ultrassom, em cada lado do abdômen: um na parte caudal da região abdominal média, cranial a crista ilíaca, e o outro ponto, caudal a última costela, com 0,5mg/kg de bupivacaína a 0,25% em cada ponto, padronizando um volume injetado de 0,6mL. Foi utilizado acepromazina (0,05mg/kg), petidina (3mg/kg), cetamina (2mg/kg) e midazolam (0,3mg/kg) como medicação pré-anestésica, indução com propofol (3mg/kg) e manutenção por anestesia inalatória com isoflurano. Conclui-se que o TAP block foi eficaz para mastectomia regional abdominal, com alto índice de segurança e de fácil execução com treinamento adequado, mesmo com transdutores de baixa frequência.

Locoregional blocks have been increasingly used in veterinary medicine. Blocking the transverse plane of the abdomen (TAP Block) is a technique of locoregional anesthesia, it is part of the multimodal analgesia strategy, capable of promoting anesthesia and analgesia in regions of skin, musculature and parietal peritoneum. The aim of this study is to report the transverse plane block in a two-year-old male cat undergoing regional mastectomy. Two ultrasound-guided TAP space block points were made on each side of the abdomen: one in the caudal part of the middle abodminal region, cranial to the iliac crest, and the other point, caudal to the last rib, with 0.5mg/kg of 0.25% bupivacaine at each point, standardizing an injected volume of 0.6mL. Acepromazine (0.05mg/kg), pethidine (3mg/kg), ketamine (2mg/kg) and midazolam (0.3mg/kg) were used as pre-anesthetic medication, induction with propofol (3mg/kg) and maintenance by inhalation anesthesia with isoflurane. It is concluded that the TAP block was effective for regional abdominal mastectomy, with a high safety index and easy to perform with adequate training, even with less frequent transducers.

Effects on the lipid peroxidation and the antioxidant defense systems of the use of isoflurane or sevoflurane in calves undergoing surgery

Background: Incoming anaesthesia created by the use of many drugs with different physicochemical properties is a sourceof stress and trauma for the body. This event increases the oxidative response and changes the balance between oxidant/antioxidant capacity in the organism in favor of oxidant capacity. This situation is defined as oxidative stress. For thesereasons, studies are conducted to determine the effects of general anaesthetic agents on oxidant and antioxidant systems inthe organism. In this study, it was aimed to determine the effects of isoflurane and sevoflurane used for general anaesthesiain humans and animals on lipid peroxidation and antioxidant defense system in calves.Materials, Methods & Results: The study included 14 calves of different breeds, ages, sexes, and weighing, average 2 weeksold. The cases randomly were divided into 2 groups, the isoflurane group (group I), and the sevoflurane group (group II),and each group included 7 animals. Before general anaesthesia, 0.04 mg/kg atropine was administered intramuscularly toall animals for premedication. At 15 min after atropine administration, isoflurane was administered at an inspiratory concentration of 3-5% in group I, and sevoflurane was administered at an inspiratory concentration of 5-7% in group II, via aface mask for 15 min for the induction of anaesthesia. Endotracheal intubation was performed in all cases at the 15 min ofthe induction period following the onset of general anaesthesia symptoms. After the induction, anaesthesia was continuedat an inspiratory concentration of 1.5-3% in the isoflurane group and inspiratory concentration of 2.5-4% in the sevofluranegroup. Blood samples were taken just before anaesthesia, just before skin incision, at the end of anaesthesia and surgery,and at the 24 h postoperatively. The malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione...

Bloqueio do plexo-braquial e peridural lombossacra em um quati (Nasua nasua) / Brachial plexus block and lumbosacral epidural in a South American coati (Nasua nasua)

Background: The South American coatis (Nasua nasua) are capable of adapting to different habitats, which allowed themto exchange between domestic and wild areas, increasing the occurrence of traumas. Procedures performed in this speciesdemand anesthetic protocols that take comorbidities into account and cause minimal cardiorespiratory depression as wellas rapid recovery. It is in such context that locoregional anesthesia has become an essential tool. Thus, we aim to reportthe use of two techniques of locoreginal block: brachial plexus block and lumbosacral epidural block, in a Nasua nasuasubmitted to osteosynthesis of the radius and caudectomy due to trauma.Case: A adult male coati weighing 2.3 kg was referred to the Veterinary Medical Teaching Hospital of the UniversidadeFederal do Paraná (UFPR) - Setor Palotina with a history of trauma. Physical examination showed crackling in the radius and ulnar region, and also abnormal angulation in the distal portion of the tail. After taking x-rays, fractures wereconfirmed in the distal radius and in the distal portion of the tail. The patient was referred for surgery. After 8 h of waterand food withdrawal, the animal was premedicated with a combination of ketamine (10 mg/kg), midazolam (0.3 mg/kg)and methadone (0.2 mg/kg), intramuscularly (IM). Induction of anesthesia was performed with propofol titrated to effect(total dose 4 mg/kg) and anesthesia was maintained with isoflurane in spontaneous ventilation using a non-rebreathingcircuit (Baraka). It was evaluated heart rate (HR), respiratory rate (RF), end-tidal CO2 (EtCO2), expired isoflurane fraction (FE´Iso), oxyhemoglobin saturation (SpO2), electrocardiography (ECG), systolic blood pressure (SBP) and coretemperature (CT) using a multiparametric monitor. After the stabilization period, the animal was positioned in lateral...

Dexmedetomidine-tiletamine-zolazepam followed by inhalant anesthesia in spectacled bears (Tremarctos ornatus)

Background: The spectacled bear (Tremarctos ornatus) is the only bear species inhabiting South America and is classified as vulnerable according to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Among the few publications on the use of general anesthesia and advanced monitoring of ursids in veterinary hospital settings, little is described regarding chemical restraint, general anesthesia and monitoring of spectacled bears. This case series describes the use of a dexmedetomidine-tiletamine-zolazepam chemical restraint combination and its effects on cardiorespiratory variables and arterial blood gases observed in two spectacled bears undergoing isoflurane anesthesia for imaging and/or surgical procedures. Cases: Two female, one adult and one senile, all-term captive spectacled bears were referred to the Veterinary Teaching Hospital at the Universidade Estadual Paulista - Unesp, Botucatu campus, both with a presumable history of recent trauma. After immobilization with an intramuscular (IM) administration of tiletamine-zolazepam (3.8 - 4.3 mg/kg) and dexmedetomidine (6.4 - 7.6 µg/kg), induction of anesthesia was achieved by means of intravenous (IV) propofol (1 - 2 mg/kg). After orotracheal intubation animals underwent isoflurane anesthesia under mechanical ventilation through the remainder of the procedures. Initial settings of inspiratory flow rate were adjusted to obtain peak airway pressure (Ppeak ) of 10 cmH2 O and tidal volumes (Vt) of 10 mL/kg, as well as respiratory rates (ƒR) and inspiration-to-expiration (I:E) ratio of 10 breaths/min and 1:2, respectively, and were then adjusted throughout anesthesia to maintain normocapnia (end-tidal carbon dioxide concentrations between 35 and 45 mmHg). One of the individuals was chemically restrained (6.4 mg/kg of tiletaminezolazepam and 7.7 µg/kg of dexmedetomidine) on a second anesthetic event for imaging...

Bloqueio do plexo-braquial e peridural lombossacra em um quati (Nasua nasua) / Brachial plexus block and lumbosacral epidural in a South American coati (Nasua nasua)

Background: The South American coatis (Nasua nasua) are capable of adapting to different habitats, which allowed themto exchange between domestic and wild areas, increasing the occurrence of traumas. Procedures performed in this speciesdemand anesthetic protocols that take comorbidities into account and cause minimal cardiorespiratory depression as wellas rapid recovery. It is in such context that locoregional anesthesia has become an essential tool. Thus, we aim to reportthe use of two techniques of locoreginal block: brachial plexus block and lumbosacral epidural block, in a Nasua nasuasubmitted to osteosynthesis of the radius and caudectomy due to trauma.Case: A adult male coati weighing 2.3 kg was referred to the Veterinary Medical Teaching Hospital of the UniversidadeFederal do Paraná (UFPR) - Setor Palotina with a history of trauma. Physical examination showed crackling in the radius and ulnar region, and also abnormal angulation in the distal portion of the tail. After taking x-rays, fractures wereconfirmed in the distal radius and in the distal portion of the tail. The patient was referred for surgery. After 8 h of waterand food withdrawal, the animal was premedicated with a combination of ketamine (10 mg/kg), midazolam (0.3 mg/kg)and methadone (0.2 mg/kg), intramuscularly (IM). Induction of anesthesia was performed with propofol titrated to effect(total dose 4 mg/kg) and anesthesia was maintained with isoflurane in spontaneous ventilation using a non-rebreathingcircuit (Baraka). It was evaluated heart rate (HR), respiratory rate (RF), end-tidal CO2 (EtCO2), expired isoflurane fraction (FE´Iso), oxyhemoglobin saturation (SpO2), electrocardiography (ECG), systolic blood pressure (SBP) and coretemperature (CT) using a multiparametric monitor. After the stabilization period, the animal was positioned in lateral...(AU)

Effects on the lipid peroxidation and the antioxidant defense systems of the use of isoflurane or sevoflurane in calves undergoing surgery

Background: Incoming anaesthesia created by the use of many drugs with different physicochemical properties is a sourceof stress and trauma for the body. This event increases the oxidative response and changes the balance between oxidant/antioxidant capacity in the organism in favor of oxidant capacity. This situation is defined as oxidative stress. For thesereasons, studies are conducted to determine the effects of general anaesthetic agents on oxidant and antioxidant systems inthe organism. In this study, it was aimed to determine the effects of isoflurane and sevoflurane used for general anaesthesiain humans and animals on lipid peroxidation and antioxidant defense system in calves.Materials, Methods & Results: The study included 14 calves of different breeds, ages, sexes, and weighing, average 2 weeksold. The cases randomly were divided into 2 groups, the isoflurane group (group I), and the sevoflurane group (group II),and each group included 7 animals. Before general anaesthesia, 0.04 mg/kg atropine was administered intramuscularly toall animals for premedication. At 15 min after atropine administration, isoflurane was administered at an inspiratory concentration of 3-5% in group I, and sevoflurane was administered at an inspiratory concentration of 5-7% in group II, via aface mask for 15 min for the induction of anaesthesia. Endotracheal intubation was performed in all cases at the 15 min ofthe induction period following the onset of general anaesthesia symptoms. After the induction, anaesthesia was continuedat an inspiratory concentration of 1.5-3% in the isoflurane group and inspiratory concentration of 2.5-4% in the sevofluranegroup. Blood samples were taken just before anaesthesia, just before skin incision, at the end of anaesthesia and surgery,and at the 24 h postoperatively. The malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione...(AU)

Intraocular pressure and pupil diameter in healthy cats anesthetized with isoflurane and pre-medicated with isolated acepromazine or in combination with tramadol / [Pressão intraocular e diâmetro pupilar em gatos saudáveis anestesiados com isoflurano e pré-medicados com acepromazina isolada ou em combinação com tramadol]

The objective of this study was to determine changes on intraocular pressure (IOP) and pupil diameter (PD) in healthy cats anesthetized with isoflurane, and premedicated with acepromazine alone or in combination with tramadol. Thirty cats were allocated in two groups (n=15/each) and were treated with acepromazine (AG) or acepromazine/tramadol (ATG). PD and IOP were assessed before and following 30 (PM1), and 40 minutes (PM2) of treatments. Anesthesia was induced with propofol, and IOP and DP were recorded (A10) at 10 minute intervals until the end of anesthesia (A40). IOP decreased in AG and ATG, when comparing baseline with PM1. IOP decreased only in AG, in comparisons between baseline and PM2. During anesthesia, IOP did not change within and between groups. Comparisons between baseline with those recorded at PM1 and 2 showed that PD increased in the ATG. During anesthesia, PD decreased significantly in AG and ATG. Both protocols maintained the IOP within the reference range to perform corneal or intraocular surgery in healthy cats but did not sustain pre-anesthetic pupil dilation observed in ATG.(AU)

O objetivo do presente artigo é determinar possíveis alterações na pressão intraocular (PIO) e no diâmetro pupilar (DP) em gatos saudáveis anestesiados com isoflurano e pré-medicados com acepromazina isolada ou em combinação com acepromazina/tramadol. Trinta gatos saudáveis foram distribuídos aleatoriamente em dois grupos (n=15/cada) e tratados com acepromazina (GA) ou acepromazina/tramadol (GAT). DP e PIO foram avaliadas antes (basal) e após 30 (PM1) e 40 minutos (PM2) dos tratamentos. A anestesia foi induzida com propofol, e a PIO e o DP foram registrados (A10) a cada 10 minutos até o final da anestesia com isoflurano (A40). Ao se compararem os valores obtidos no basal com PM1, a PIO diminuiu em GA e GAT; com PM2, a PIO reduziu apenas no GA. Durante a anestesia, a PIO não diferiu dentro e entre os grupos. Comparações entre os valores basais e os registrados em PM1 e em PM2 mostraram que a DP aumentou significativamente no GAT. Durante a anestesia, o DP diminuiu significativamente em GA e GAT. Ambos os protocolos mantêm a PIO dentro dos valores de referência para realizar cirurgias corneanas ou intraoculares em gatos saudáveis, mas não sustentam a dilatação pupilar pré-anestésica observada em GAT.(AU)

Parâmetros hemodinâmicos e ventilatórios em coelhos anestesiados com isoflurano, submetidos à ventilação controlada à pressão com ou sem PEEP / Hemodynamic and ventilatory parameters in rabbits anesthetized with isoflurane submitted to pressure controlled ventilation with or without PEEP

Foi comparada a ventilação controlada à pressão com ou sem pressão positiva expiratória final (PEEP), em coelhos, distribuídos em três grupos, denominados GP (grupo ventilação ciclada à pressão), GPP (grupo ventilação ciclada à pressão com PEEP) e GE (grupo ventilação espontânea - grupo controle). Os animais foram anestesiados com isoflurano, em circuito com reinalação de gases, durante duas horas. As médias de pressão arterial média (PAM) e pressão arterial sistólica (PAS) permaneceram discretamente abaixo dos valores normais em todos os grupos. Houve diminuição significativa da PAM e da PAS no grupo submetido à PEEP (GPP) ao longo do tempo. A pressão parcial de dióxido de carbono arterial (PaCO2) foi maior no GPP quando comparado aos outros grupos no último momento, gerando acidemia respiratória após uma hora de procedimento. A concentração de dióxido de carbono ao final da expiração (ETCO2) apresentou médias discretamente elevadas no grupo não tratado com PEEP (GP) e no grupo controle, enquanto o GPP apresentou maiores médias, possivelmente, relacionadas à diminuição do volume corrente neste grupo. Com base nesses resultados, foi possível concluir que a utilização da PEEP levou à acidemia, que se agravou ao longo do tempo anestésico. Ademais, a anestesia prolongada com isoflurano promove depressão cardiorrespiratória, independentemente do modo ventilatório empregado.(AU)

Pressure controlled ventilation with or without positive end-expiratory pressure (PEEP) was compared in rabbits, which were divided into three groups denominated GP (pressure cycled ventilation group), GPP (pressure cycled ventilation with PEEP group) and GE (spontaneous ventilation group - control group). The animals were anesthetized with isoflurane in a gas rebreathing circuit for two hours. The means of mean arterial pressure (MAP) and systolic blood pressure (SBP) remained slightly below normal values ​​in all groups. There was a significant decrease in MAP and SBP in the group submitted to PEEP (GPP) over time. The partial pressure of arterial carbon dioxide (PaCO2) was higher in GPP when compared to the other groups, inducing respiratory acidosis after one hour. The end-expired carbon dioxide concentration (ETCO2) presented slightly elevated means in the GP, while the GPP presented higher means, possibly related to the decrease in tidal volume in this group. Based on these results it was concluded that the use of PEEP led to acidemia that worsened over anesthetic time. In addition, prolonged isoflurane anesthesia promotes cardiorespiratory depression, regardless the ventilatory mode employed.(AU)

Parâmetros hemodinâmicos e ventilatórios em coelhos anestesiados com isoflurano, submetidos à ventilação controlada à pressão com ou sem PEEP / Hemodynamic and ventilatory parameters in rabbits anesthetized with isoflurane submitted to pressure controlled ventilation with or without PEEP

Foi comparada a ventilação controlada à pressão com ou sem pressão positiva expiratória final (PEEP), em coelhos, distribuídos em três grupos, denominados GP (grupo ventilação ciclada à pressão), GPP (grupo ventilação ciclada à pressão com PEEP) e GE (grupo ventilação espontânea - grupo controle). Os animais foram anestesiados com isoflurano, em circuito com reinalação de gases, durante duas horas. As médias de pressão arterial média (PAM) e pressão arterial sistólica (PAS) permaneceram discretamente abaixo dos valores normais em todos os grupos. Houve diminuição significativa da PAM e da PAS no grupo submetido à PEEP (GPP) ao longo do tempo. A pressão parcial de dióxido de carbono arterial (PaCO2) foi maior no GPP quando comparado aos outros grupos no último momento, gerando acidemia respiratória após uma hora de procedimento. A concentração de dióxido de carbono ao final da expiração (ETCO2) apresentou médias discretamente elevadas no grupo não tratado com PEEP (GP) e no grupo controle, enquanto o GPP apresentou maiores médias, possivelmente, relacionadas à diminuição do volume corrente neste grupo. Com base nesses resultados, foi possível concluir que a utilização da PEEP levou à acidemia, que se agravou ao longo do tempo anestésico. Ademais, a anestesia prolongada com isoflurano promove depressão cardiorrespiratória, independentemente do modo ventilatório empregado.(AU)

Pressure controlled ventilation with or without positive end-expiratory pressure (PEEP) was compared in rabbits, which were divided into three groups denominated GP (pressure cycled ventilation group), GPP (pressure cycled ventilation with PEEP group) and GE (spontaneous ventilation group - control group). The animals were anesthetized with isoflurane in a gas rebreathing circuit for two hours. The means of mean arterial pressure (MAP) and systolic blood pressure (SBP) remained slightly below normal values ​​in all groups. There was a significant decrease in MAP and SBP in the group submitted to PEEP (GPP) over time. The partial pressure of arterial carbon dioxide (PaCO2) was higher in GPP when compared to the other groups, inducing respiratory acidosis after one hour. The end-expired carbon dioxide concentration (ETCO2) presented slightly elevated means in the GP, while the GPP presented higher means, possibly related to the decrease in tidal volume in this group. Based on these results it was concluded that the use of PEEP led to acidemia that worsened over anesthetic time. In addition, prolonged isoflurane anesthesia promotes cardiorespiratory depression, regardless the ventilatory mode employed.(AU)

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...