Flap of the sternocephalicus muscle in the repair of a partial defect in the trachea of a rabbit (Oryctolagus cuniculus)

Purpose: The current study aimed at evaluating the repair of a partial defect of the trachea with a muscle flap, an advanced technique that employs combined suture patterns. Methods: Sixteen healthy male New Zealand white rabbits were used as an experimental model. A partial defect in the trachea within the ventral region of the fourth to eighth tracheal ring was created. Subsequently, repair was initiated with a flap of the sternocephalicus muscle. The animals were divided into four groups for postoperative evaluation using clinical, tracheoscopic, and histopathological analyses. Each group was separated according to the time of euthanasia, programmed at interval of seven (G7), 15 (G15), 30 (G30), and 60 days (G60). Results: One animal from the G60 group died, whereas the other animals had good surgical recovery without serious changes in the breathing pattern. The major clinical signs observed were stridor and coughing. Tracheoscopy revealed secretions in the tracheal lumen, exuberant granulation, and stenosis. Histopathological analysis showed growth of the ciliary respiratory epithelium at the flap site 30 days after implantation. Conclusions: Partial repair showed satisfactory results owing to the anatomical location of the muscle, adequate vascular support, and structural and physiological maintenance without serious changes in the respiratory system.

Diseño y comparativa de biomateriales para el tratamiento de defectos óseos. Estudio de su comportamiento in vivo en modelo animal de conejo / Desing and comparison of bone substitutes. Study of in vivo behavior in a rabbit model

Objetivo: Comparar in vivo la capacidad de formación ósea de dos tipos de biomateriales diseñados como sustitutivos óseos respecto a autoinjerto de cresta iliaca, uno basado en carbonatohidroxiapatita y otro en vidrio mesoporoso bioactivo. Material y método: Estudio experimental compuesto por 14 conejos de Nueva Zelanda hembras adultas donde se realizó un defecto crítico en hueso radio. La muestra fue dividida en cuatro grupos: defecto sin material, con autoinjerto de cresta iliaca, con soporte de carbonatohidroxiapatita y con soporte de vidrio mesoporoso bioactivo. Se realizaron estudios seriados de radiología simple a las 2, 4, 6 y 12 semanas y estudio de micro-TC a eutanasia a las 6 y 12 semanas. Resultados: En el estudio de radiología simple, el grupo de autoinjerto mostró las mayores puntuaciones de formación ósea (7,5 puntos). Ambos grupos de biomateriales presentaron formación ósea similar (5,3 y 6 puntos, respectivamente) y mayor al defecto sin material (4 puntos), pero siempre menor que el grupo de autoinjerto. Los resultados del estudio de micro-TC mostraron el mayor volumen de hueso en el área de estudio en el grupo de autoinjerto. Los grupos con sustitutivos óseos presentaron mayor volumen de hueso que el grupo sin material, pero siempre menor que en el grupo de autoinjerto. Conclusiones: Ambos soportes parecen favorecer la formación ósea pero no son capaces de reproducir las características del autoinjerto. Por sus diferentes características macroscópicas cada uno podría ser adecuado para un tipo diferente de defecto.(AU)

Aim: Compare bone formation capacity in vivo of two types of biomaterials designed as bone substitutes with respect to iliac crest autograft, one based on carbonate hydroxyapatites and the other one on bioactive mesoporous glass. Materials and methods: Experimental study consisting on 14 adult female New Zeland rabbits where a critical defect was made in the rabbit radius bone. The sample was divided into four groups: defect without material, with iliac crest autograft, with carbonatehydroxyapatite support, and with bioactive mesoporous glass support. Serial X-ray studies were carried out at 2, 4, 6 and 12 weeks and a microCT study at euthanasia at 6 and 12 weeks. Results: In the X-ray study, autograft group showed the highest bone formation scores. Both groups of biomaterials presented bone formation similar and greater than the defect without material, but always less than in the autograft group. The results of the microCT study showed the largest bone volume in the study area in the autograft group. The groups with bone substitutes presented greater bone volume than the group without material but always less than in the autograft group. Conclusion: Both supports seem to promote bone formation but are not capable of reproducing the characteristics of autograft. Due to their different macroscopic characteristics, each one could be suitable for a different type of defect.(AU)

[Translated article] Design and comparison of bone substitutes. Study of in vivo behaviour in a rabbit model / Diseño y comparativa de biomateriales para el tratamiento de defectos óseos. Estudio de su comportamiento in vivo en modelo animal de conejo

Objetivo: Comparar in vivo la capacidad de formación ósea de dos tipos de biomateriales diseñados como sustitutivos óseos respecto a autoinjerto de cresta iliaca, uno basado en carbonatohidroxiapatita y otro en vidrio mesoporoso bioactivo. Material y método: Estudio experimental compuesto por 14 conejos de Nueva Zelanda hembras adultas donde se realizó un defecto crítico en hueso radio. La muestra fue dividida en cuatro grupos: defecto sin material, con autoinjerto de cresta iliaca, con soporte de carbonatohidroxiapatita y con soporte de vidrio mesoporoso bioactivo. Se realizaron estudios seriados de radiología simple a las 2, 4, 6 y 12 semanas y estudio de micro-TC a eutanasia a las 6 y 12 semanas. Resultados: En el estudio de radiología simple, el grupo de autoinjerto mostró las mayores puntuaciones de formación ósea (7,5 puntos). Ambos grupos de biomateriales presentaron formación ósea similar (5,3 y 6 puntos, respectivamente) y mayor al defecto sin material (4 puntos), pero siempre menor que el grupo de autoinjerto. Los resultados del estudio de micro-TC mostraron el mayor volumen de hueso en el área de estudio en el grupo de autoinjerto. Los grupos con sustitutivos óseos presentaron mayor volumen de hueso que el grupo sin material, pero siempre menor que en el grupo de autoinjerto. Conclusiones: Ambos soportes parecen favorecer la formación ósea pero no son capaces de reproducir las características del autoinjerto. Por sus diferentes características macroscópicas cada uno podría ser adecuado para un tipo diferente de defecto.(AU)

Aim: Compare bone formation capacity in vivo of two types of biomaterials designed as bone substitutes with respect to iliac crest autograft, one based on carbonate hydroxyapatites and the other one on bioactive mesoporous glass. Materials and methods: Experimental study consisting on 14 adult female New Zeland rabbits where a critical defect was made in the rabbit radius bone. The sample was divided into four groups: defect without material, with iliac crest autograft, with carbonatehydroxyapatite support, and with bioactive mesoporous glass support. Serial X-ray studies were carried out at 2, 4, 6 and 12 weeks and a microCT study at euthanasia at 6 and 12 weeks. Results: In the X-ray study, autograft group showed the highest bone formation scores. Both groups of biomaterials presented bone formation similar and greater than the defect without material, but always less than in the autograft group. The results of the microCT study showed the largest bone volume in the study area in the autograft group. The groups with bone substitutes presented greater bone volume than the group without material but always less than in the autograft group. Conclusion: Both supports seem to promote bone formation but are not capable of reproducing the characteristics of autograft. Due to their different macroscopic characteristics, each one could be suitable for a different type of defect.(AU)

In vivo evaluation of deer antler trabecular bone as a reconstruction material for bone defects.

Availability of graft materials to fill up osseous defects has always been a concern in orthopaedic surgeries. Deer antler material is a primary bone structure that is easy to collect and could serve as a xenograft. This study examines the behaviour of red deer antler trabecular cylinders in critical size distal femoral epiphyseal defects in 11 rabbits, and evaluates the effect of the decellularization protocols. Two preparation regimes (A and B) were used, with and without lipids and proteins. Radiographs were taken immediately after surgery and after euthanasia 12 weeks post-implantation. Histological evaluation was performed on non-decalcified 10-µm sections with a van Gieson picro-fuchsin staining protocol. A region of interest was defined for each histological section, evaluating the inflammatory reaction, the fibrosis process, and the osteogenesis. Each histological section was microradiographed to evaluate bone contact, presence of synostosis, remodelling and ossification processes. All antler cylinders were successfully implanted. Final radiographic analysis demonstrated osteointegration of most implants at various stages. Light to moderate inflammation around the grafts was noted with only one case showing full encapsulation. A variable degree of intimacy between implant and host bone was evidenced, with bone remodelling and osteogenesis of various intensity being present in all implanted sites. No differences were found between group A and B. Removal of lipids and proteins in the grafts surprisingly did not seem to matter. Decellularization and sterilization protocols may be advocated. Although it presents several limitations, this study shows some promising results regarding antler trabecular bone osteointegration.

Comparison of endoscopic endotracheal intubation and the v-gel supraglottic airway device for spontaneously ventilating New Zealand white rabbits undergoing ovariohysterectomy.

BACKGROUND: Due to the technical difficulties with endotracheal intubation of rabbits, a prospective, randomised, controlled study was performed to compare a rabbit-specific supraglottic airway device (SGAD), the v-gel, with endoscopic endotracheal intubation (EEI) in spontaneously breathing rabbits undergoing ovariohysterectomy. METHODS: Fourteen adult female New Zealand white rabbits were randomly allocated to one of two groups based on the method of airway establishment: EEI or v-gel SGAD. Anaesthesia was induced with ketamine and xylazine and maintained using isoflurane in 100 per cent oxygen. Comparisons were made between groups based on placement time of endotracheal tube/SGAD, number of attempts and adjustments, the necessity to increase isoflurane concentrations to maintain a surgical plane of anaesthesia, arterial blood gas values, gross laryngeal evaluation, and laryngotracheal histopathology. RESULTS: Both techniques resulted in elevated arterial pCO2 levels, but the v-gel was associated with more elevated pCO2 in comparison with EEI (P=0.045). Airway trauma was histologically present but clinically negligible in both groups, with no statistically significant differences observed between techniques (P>0.05). Placement time of the v-gel was significantly faster (P=0.003) and required less technical skill than EEI, but was more easily displaced when changing the animal's position (P=0.004). CONCLUSION: The v-gel is a practical alternative to EEI for securing the airway of healthy spontaneously ventilating rabbits, provided a capnograph is utilised to ensure continuous placement. Both airway techniques appear safe and effective with few complications, as long as intermittent positive pressure ventilation can be employed to correct hypercapnia.

Região metafisária da tíbia de coelhos: uma opção para estudos dos substitutos ósseos / Metaphyseal region of the tibia of rabbits: an option for bone substitutes studies

Apresenta-se um modelo experimental de ostectomia de tíbia em coelhos para estudo de biomateriais em processos de reparação óssea. Foi realizada falha segmentar de 6mm de diâmetro na região metafisária medial proximal de tíbia de 72 coelhos as quais foram preenchidas com substituto ósseo e avaliadas clinicamente, por exame radiográfico e por meio de tomografia computadorizada feixe cônico, em diferentes tempos. Conclui-se que a metáfise medial proximal de tíbia de coelhos é adequada como modelo para estudos que avaliem o comportamento de enxertos e/ou biomateriais em falhas ósseas.

Is presented an experimental model of tibial ostectomy in rabbits to study biomaterials during bone repair process. Segmental failure of 6 mm diameter was performed in the medial proximal tibial metaphyseal region of 72 rabbits, which were filled with bone substitute and evaluated by clinical exam, X-ray, and cone beam computed tomography at different times. It is concluded that the medial proximal tibial metaphysis region of rabbits is suitable as a model for studies that evaluate the behavior of grafts and/or biomaterials on bone defects.

Região metafisária da tíbia de coelhos: uma opção para estudos dos substitutos ósseos / Metaphyseal region of the tibia of rabbits: an option for bone substitutes studies

Apresenta-se um modelo experimental de ostectomia de tíbia em coelhos para estudo de biomateriais em processos de reparação óssea. Foi realizada falha segmentar de 6mm de diâmetro na região metafisária medial proximal de tíbia de 72 coelhos as quais foram preenchidas com substituto ósseo e avaliadas clinicamente, por exame radiográfico e por meio de tomografia computadorizada feixe cônico, em diferentes tempos. Conclui-se que a metáfise medial proximal de tíbia de coelhos é adequada como modelo para estudos que avaliem o comportamento de enxertos e/ou biomateriais em falhas ósseas.

Is presented an experimental model of tibial ostectomy in rabbits to study biomaterials during bone repair process. Segmental failure of 6 mm diameter was performed in the medial proximal tibial metaphyseal region of 72 rabbits, which were filled with bone substitute and evaluated by clinical exam, X-ray, and cone beam computed tomography at different times. It is concluded that the medial proximal tibial metaphysis region of rabbits is suitable as a model for studies that evaluate the behavior of grafts and/or biomaterials on bone defects.

Continuous Rate Infusion of Ketamine Hydrochloride and Dexmedetomidine for Maintenance of Anesthesia during Laryngotracheal Surgery in New Zealand White Rabbits (Oryctolagus cuniculus).

New Zealand white rabbits (Oryctolagus cuniculus) are an established in vivo model for the study of structural and functional consequences of vocal-fold vibration. Research design requires invasive laryngotracheal procedures, and the presence of laryngospasms or pain responses (or both) hinder phonation-related data collection. Published anesthesia regimens report respiratory depression and muscle tone changes and have been unsuccessful in mitigating autonomic laryngeal responses in our protocol. Infusion of ketamine hydrochloride and dexmedetomidine hydrochloride in pediatric medicine provides effective analgesia and sedation for laryngotracheal procedures including intubation and bronchoscopy; however, data evaluating the use of ketamine-dexmedetomidine infusion in rabbits are unavailable. This study reports a new infusion regimen, which was used in 58 male New Zealand white rabbits that underwent a nonsurvival laryngotracheal procedure to induce phonotraumatic vocal-fold injury. Animals were sedated by using ketamine hydrochloride (20 mg/kg IM) and dexmedetomidine (0.125 mg/kg IM). Maintenance anesthesia was provided by using continuous rate intravenous infusion of ketamine hydrochloride (343 µg/kg/min) and dexmedetomidine (1.60 µg/kg/min). A stable plane of anesthesia with no autonomic laryngeal response (laryngospasm) was achieved in 32 of the 58 rabbits (55%). Laryngospasms occurred in 25 of 58 animals (43%) and were controlled in 20 cases (80%) by providing 0.33 mL 2% topical lidocaine, incremental increase in infusion rate, or both. Continuous rate infusion of ketamine hydrochloride-dexmedetomidine with prophylactic topical lidocaine provides a predictable and adjustable surgical plane of anesthesia, with minimal confounding respiratory and autonomic laryngeal responses, during extended-duration laryngotracheal surgery in rabbits. This regimen should be considered as an alternative to injection maintenance for prolonged, invasive procedures.

A novel surgical technique for enucleation in rabbits to reduce the risk of intra- and post-operative orbital hemorrhage.

A 10-year-old male castrated Holland Lop rabbit (Oryctolagus cuniculus) was presented for severe ulcerative stromal keratitis of the right eye and a luxated hypermature cataract and glaucoma of the left eye. Staged bilateral enucleation was elected. A LigaSure™ electrosurgical bipolar vessel-sealing device was used as a means to minimize intraoperative and post-operative hemorrhage, especially that associated with the orbital venous plexus. The LigaSure™ was used to ligate and transect all extraocular muscles, the optic nerve bundle, and the base of the third eyelid with no complications encountered. Overall, the LigaSure™ was easy to use, resulted in minimal hemorrhage, and reduced surgery time. This is the first report of the use of a LigaSure™ to aid in the enucleation of a rabbit. Although only positive results were achieved as an alternative to conventional methodologies, its use in clinical practice should be that of caution until a larger study evaluating the long-term results is performed.

Comparison of 3 intraosseous catheter sites and methods of determining placement success in cadaver rabbits.

The study goals were to determine if intraosseous (IO) catheters can be placed with greater success into the humerus, femur, or tibia of cadaver rabbits, and to evaluate the accuracy of perceived success (PS) and objective clinical success (OCS) criteria against true intramedullary catheterization confirmed by fluoroscopy. This was a prospective study utilizing 12 rabbit cadavers. Twenty-two participants attempted IO catheter placement at 3 sites. Perceived success, OCS, and fluoroscopic true success (FTS) were recorded. A Fisher's exact test was used to compare PS, OCS, and FTS, and FTS rates between sites (P < 0.05). A Wilcoxon test was used to compare speed of placement (P < 0.05). Overall, of 66 attempts, PS was reported in 86.4%, OCS was documented in 62.1%, FTS was confirmed in 43.9%. Perceived success and OCS overestimated FTS (P ≤ 0.01 and P = 0.027, respectively). Confirmation of FTS occurred in 10/22 (45.5%) humeral, 5/22 (22.7%) femoral, and 14/22 (63.6%) tibial (P = 0.03) attempts. Median time until placement for the humerus was 37.5 seconds (range: 15 to 125 seconds); the femur 135 seconds (range: 91 to 148 seconds); the tibia 49 seconds (range: 19 to 150 seconds). The humerus and tibia were faster to catheterize than the femur (P = 0.01 and 0.03, respectively). Participant PS and OCS criteria overestimated FTS. The humerus or tibia may be more successful and are faster to catheterize.

Les objectifs de la présente étude étaient de déterminer si des cathéters intra-osseux (IO) peuvent être placés avec plus de succès dans l'humérus, le fémur ou le tibia de cadavres de lapins, et d'évaluer la précision des critères du succès perçu (PS) et du succès clinique objectif (OCS) versus le cathétérisme intramédullaire réel confirmé par fluoroscopie. Il s'agissait d'une étude prospective utilisant 12 cadavres de lapin. Vingt-deux participants ont tenté le placement des cathéters IO aux trois sites. Le PS, l'OCS et le succès réel par fluoroscopie (FTS) furent notés. Un test exact de Fisher fut utilisé pour comparer PS, OCS, et FTS, et les taux de FTS entre les sites (P < 0,05). Un test de Wilcoxon a été utilisé pour comparer la vitesse de placement (P < 0,05). Globalement, des 66 essais, PS a été rapporté dans 86,4 % des cas, OCS a été documenté dans 62,1 % des cas, et FTS a été confirmé dans 43,9 % des cas. Le PS et l'OCS surestimaient le FTS (P ≤ 0,01 et P = 0,027, respectivement). La confirmation de FTS s'est produite dans 10/22 (45,5 %) des essais sur l'humérus, 5/22 (22,7 %) des essais sur le fémur, et 14/22 (63,6 %) des essais sur le tibia (P = 0,03).Le temps médian du placement pour l'humérus était de 37,5 secondes (écart : 15 à 125 secondes); pour le fémur de 135 secondes (écart : 91 à 148 secondes); et pour le tibia de 49 secondes (écart : 19 à 150 secondes). Le cathétérisme de l'humérus et du tibia étaient plus rapides que celui du fémur (P = 0,01 et 0,03, respectivement). Les critères pour le PS et l'OCS des participants surestimaient le FTS. L'humérus et le tibia sont plus rapides à cathétériser et le taux de succès est meilleur.(Traduit par Docteur Serge Messier).

Rabbit growth plate morphology in temporary bilateral blocking / Morfología de la placa de crecimiento de conejos durante bloqueo bilateral temporario

Blocking of the growth plate (GP) using plates with screws (tension band plating) is a modern method used to correct deformities and moderate leg length discrepancy in growing children. Determining the duration of temporary bilateral blocking without the occurrence of irreversible changes of GP is of paramount importance important. Methods: Two-month-old Californian breed male rabbits (n=30) were exposed to bilateral blocking of the distal GP of the right femur locking plates with screws for 3, 5, and 7 weeks. The fixators were removed after 5 and 7 weeks in 18 rabbits and 3 weeks after that, animals were sacri!ced. The contralateral limb was used as a control. Histological, histomorphometric, and X-ray analyses were performed. Results: During GP blocking, its height gradually decreased. This decreased was more pronounced after 7 weeks. Destructive changes progressed with an increase in the blocking duration. Three weeks after discontinuation of the bilateral blocking that lasted 5 weeks, the height of the GP signi!cantly increased 1.2 times on the lateral side and 1.9 times on the medial side (p<0.001) compared to the control. When blocking was discontinued after 7 weeks, the structure of the GP was partially restored after 3 weeks, the height of GP signi!cantly increased 1.2 times on the lateral side, and 1.07 times on the medial side (p<0.01) compared to the control. Conclusion: Restoration of the structuralfunctional features of the GP after the removal of the plates depends on the duration of temporary bilateral blocking, which must be taken into account in the clinical setting. (AU)

El bloqueo de la placa de crecimiento (PC) utilizando placas con tornillos (banda de tensión) es un método moderno utilizado para corregir deformidades y alteraciones moderadas en la longitud de las piernas en niños en crecimiento. Es de suma importancia determinar cuál debe ser la duración del bloqueo bilateral temporal sin que ocurran cambios irreversibles en la PC. Métodos: Conejos machos de raza californiana de dos meses de edad (n = 30) fueron expuestos al bloqueo bilateral de la PC distal colocando placas del fémur derecho con tornillos durante 3, 5 y 7 semanas. Los fijadores fueron retirados después de 5 y 7 semanas en 18 de los conejos, y 3 semanas después los animales fueron sacrificados. La extremidad contralateral se utilizó como control. Se realizaron análisis histológicos, histomorfométricos y de rayos X. Resultados: Durante el bloqueo de la PC, su altura disminuyó gradualmente. Esta disminución fue más pronunciada después de 7 semanas. Los cambios destructivos se incrementaron a medida aumentaba la duración del bloqueo. Tres semanas después de la interrupción del bloqueo bilateral que duró 5 semanas, la altura de la PC aumentó significativamente 1.2 veces en el lado lateral y 1.9 veces en el lado medial (p <0.001) en comparación con el control. Conclusión: La restauración de las características funcionales estructurales de la PC después de la extracción de las placas depende de la duración del bloqueo bilateral temporal, lo que debería tenerse en cuenta en el tratamiento clínico de estas alteraciones. (AU)

Effects of inspired oxygen fractions in rabbits anesthetized with isoflurane or sevoflurane, maintained on spontaneous ventilation / Efeitos de frações inspiradas de oxigênio em coelhos anestesiados com isoflurano ou sevofluorano, mantidos em ventilação espontânea

It is important to identify the best inspired fraction of oxygen in a variety of situations, including sevoflurane or isoflurane anesthesia, in spontaneously breathing rabbits. For this, 64 rabbits were assigned to eight groups: GI100 (FiO2= 1,0 + isoflurane), GS100 (FiO2= 1,0 + sevoflurane), GI80 (FiO2= 0,8 + isoflurane), GS80 (FiO2= 0,8 + sevoflurane), GI60 (FiO2= 0,6 + isoflurane), GS60 (FiO2= 0,6 + sevoflurane), GI21 (FiO2= 0,21 + isoflurane), GS21 (FiO2= 0,21 + sevoflurane). The induction was performed with (2.5MAC) of the anesthetic. The vaporizer was setted at 1.5 MAC and FiO2 as attributed for each group. After the induction, the concentration was changed to 1 MAC. Measurements of parameters were performed 30 minutes after induction (T0), and then at 15 minute intervals (from T15 to T60). The arterial partial pressures of oxygen (PaO2), alveolar oxygen partial pressure (PAO2) and alveolar-arterial oxygen gradient [P(A-a)O2] were higher with the use of high FiO2. The GI80 showed higher levels of PaO2 FiO2 ratio and respiratory index (RI). In conclusion, the FiO2 of 0.21 is not indicated, because it causes hypoxemia. The isoflurane determines better ventilation when compared to sevoflurane, but isoflurane associated with 80% of oxygen promotes intrapulmonary shunt increase.(AU)

Tornou-se importante identificar a melhor fração inspirada de oxigênio em variadas situações, incluindo anestesia pelo sevoflurano ou isoflurano, em coelhos respirando espontaneamente. Para isso, 64 coelhos foram distribuídos em oito grupos: GI100 (FiO 2 = 1,0 + isoflurano), GS100 (FiO 2 = 1,0 + sevoflurano), GI80 (FiO 2 = 0,8 + isoflurano), GS80 (FiO 2 = 0,8 + sevoflurano), GI60 (FiO 2 = 0,6 + isoflurano), GS60 (FiO 2 = 0,6 + sevoflurano), GI21 (FiO 2 = 0,21 + isoflurano) e GS21 (FiO 2 = 0,21 + sevoflurano). A indução foi com 2,5 CAM do anestésico. Ajustou-se o vaporizador para 1,5 CAM, e a FiO 2 foi atribuída a cada grupo. Em seguida, a CAM foi reajustada para 1,0. Iniciaram-se as mensurações 30 minutos após a indução (M0), seguidas em intervalos de 15 minutos (de M15 a M60). As pressões parciais de oxigênio (PaO 2 ), a pressão parcial alveolar de oxigênio (P A O 2 ) e a diferença alvéolo-arterial de oxigênio [P(A-a)O 2 ] foram maiores com o emprego de altas FiO 2 . O GI80 apresentou maiores valores na relação entre PaO 2 e FiO 2 e índice respiratório (IR). Conclui-se que a FiO 2 0,21 não é indicada, pois provoca hipoxemia. No entanto, utilizada com isoflurano, determina melhor ventilação quando comparado ao sevoflurano, porém seu uso, associado a 80% de oxigênio, promove maior formação de shunt intrapulmonar.(AU)

Human Infant Pants for Postoperative Protection during Social Housing of New Zealand White Rabbits (Oryctolagus cuniculus).

Elizabethan collars (E-collars) are commonly used in various species to safeguard healing wounds. However, E-collars inadvertently restrict the expression of normal species-typical behaviors, including coprophagy, self-grooming, and social housing. To maintain social housing in accordance with recommendations in the 8th edition of the Guide for the Care and Use of Laboratory Animals, we implemented the use of human infant pants instead of E-collars for postsurgical protection. We retrospectively reviewed the medical records of 154 intact male New Zealand white rabbits (age, 2 to 3 mo) regarding the use of E-collars (group 1; n = 72) compared with human infant pants (group 2; n = 82) for postoperative protection after 308 femoral angioplasty procedures. Maintenance of social pairs throughout the postoperative phase, replacement rate of infant pants, and self-mutilation rates were measured. Our findings indicate that using infant pants for postoperative protection was most successful in maintaining social housing, offers a more cost-effective option to E-collars, and does not increase the rate of self-mutilation in intact male New Zealand white rabbits.

Use of atracurium and its reversal with neostigmine in 14 pet rabbits undergoing ophthalmic surgery: a retrospective study.

The objective of this retrospective study was to report the clinical use of atracurium and its reversal with neostigmine in pet rabbits. The medical records of 14 rabbits undergoing anaesthesia for ophthalmic surgery were located through a search of the hospital's database. Demographic data and data pertaining to the use of the neuromuscular blocker and its reversal were analysed. After intravenous administration of 0.44±0.4 mg/kg atracurium (total dose), 11 rabbits experienced at least one of the following cardiovascular responses: hypotension, defined as systolic arterial pressure less than 75 mmHg (n=6), hypotension with decreased heart rate (HR) (n=1), hypotension with increased HR (n=1), decreased arterial blood pressure (ABP) without hypotension (n=6), decreased ABP with decreased HR (n=1), or increased HR (n=2, ABP reading could not be taken). Two of these 11 rabbits also experienced severe intraoperative hypothermia. The neuromuscular block was monitored with a train-of-four nerve-stimulation pattern, and reversed, with intramuscular 0.01-0.045 mg/kg neostigmine and 0.01-0.02 mg/kg glycopyrronium, after the return of at least two out of four muscular twitches following nerve stimulation. Decrease in ABP and possibly hypothermia are likely intraoperative complications when clinical doses of atracurium are administered to pet rabbits. Measures should be taken to detect their occurrence in order to treat them promptly.

Pain and analgesia in pet rabbits within the veterinary environment: a review.

OBJECTIVE: To provide an overview of pain and analgesia in rabbits with the aim of developing a more accurate understanding of these topics. To illustrate and discuss the areas that have advanced in recent years and those that still require further research. DATABASES USED: Three key subject resources were used: Web of Science, Medline and CAB Abstracts. Search terms were rabbits, lagomorphs, laboratory animals, pet, pain, surgical procedures, ovariohysterectomy, orchiectomy, castration, analgesia, opioids, and non-steroidal anti-inflammatory drugs. References from books and articles relevant to the topics were also included. CONCLUSIONS: Rabbit medicine has improved over the last 20 years, but the literature suggests that pain management in this species is still inadequate and veterinary professionals believe their knowledge of pain and analgesia in this species is limited. Assessment and quantification of pain in rabbits can be challenging in a clinical environment not only because, as a prey species, rabbits tend to hide signs of pain but also because there are no validated methods to assess pain, except the Rabbit Grimace Scale, which is based on only one rabbit breed. Current consensus is that perioperative multimodal analgesia is the best practice. However, it is not widely used in rabbits. In rabbits, analgesia protocols and dosages reported in the literature are often poorly researched and do not result in complete pain amelioration with the return of normal. The present literature on rabbit pain and analgesia presents gaps either due to unexplored areas or insufficient findings. Further research should focus on these areas with the aim of improving the welfare of rabbits within a veterinary clinic.

Propofol: a safe anaesthetic drug in experimental cardiac surgery in rabbits.

ACKGROUND: Experimental surgery needs a pharmacological approach that can interfere with cardiac function. CASE REPORT: In a animal model of regenerative medicine of myocardium we use an anaesthesiological protocol that included Propofol, a benzodiazepine (Midazolam) and an alpha-2 adrenergic agent. RESULTS: In a group of 15 rabbits undergoing cardiac surgery we reported 1 arrhythmic complication during stem cell injection. DISCUSSION: The functional cardio- respiratory depressor activity of Propofol was compensated by alpha-2 adrenergic drugs, avoiding serious complications. We hypothesize that the functional cardio-respiratory depressor of different anaesthesiological drugs can be reversed by the contemporary administration of with adrenergic agents. KEY WORDS: Arrhythmias, Cardiac ischemia, Cardiovascular toxicity, Propofol.

Outcome of limb fracture repair in rabbits: 139 cases (2007-2015).

OBJECTIVE To evaluate outcome of limb fracture repair in rabbits. DESIGN Retrospective case series. ANIMALS 139 client-owned rabbits with limb fractures treated between 2007 and 2015. PROCEDURES Medical records were reviewed for information on fracture location, fracture treatment, and time to fracture healing. RESULTS 25 rabbits had fractures involving the distal aspects of the limbs (ie, metacarpal or metatarsal bones, phalanges, and calcaneus or talus). Fractures were treated in 23 of these 25 rabbits (external coaptation, n = 17; external skeletal fixation, 4; and intramedullary pinning, 2) and healed in all 23, with a median healing time of 28 days (range, 20 to 45 days). One hundred ten rabbits had long bone fractures, and fractures were treated in 100 of the 110 (external skeletal fixation, n = 89; bone plating, 1; intramedullary pinning, 3; and external coaptation, 7). The percentage of fractures that healed was significantly lower for open (14/18) than for closed (26/26) tibial fractures and was significantly lower for femoral (19/26) and treated humeral (4/6) fractures than for radial (23/24) or closed tibial (26/26) fractures. Micro-CT was used to assess fracture realignment during external skeletal fixator application and to evaluate fracture healing. CONCLUSIONS AND CLINICAL RELEVANCE The prognosis for rabbits with limb fractures was good, with fractures healing in most rabbits following fracture repair (109/123). Micro-CT was useful in assessing fracture realignment and evaluating fracture healing.

Four cases of iridociliary tumors in domestic rabbits (Oryctolagus Cuniculus).

Spontaneously occurring ocular neoplasia is rarely reported in rabbits. This case series presents four cases of rabbits diagnosed with iridociliary tumors, which have not been previously reported in this species. Major pathological findings include epithelial tumors affecting the anterior uvea with variable pigmentation and basement membrane formation. Follow-up information was only available for two cases, but neither showed evidence of metastasis, suggesting that the prognosis for these tumors in rabbits, as in other species, may be very good.