In guineafowl, the MAC for sevoflurane was similar to values reported for other species. Increasing the butorphanol dosage decreased the MAC for sevoflurane, but the effect was small and of short duration for dosages up to 4 mg/kg.
BackgroundSevoflurane potently enhances glycine receptor currents and more modestly decreases NMDA receptor currents, each of which may contribute to immobility. This modest NMDA receptor antagonism by sevoflurane at a minimum alveolar concentration (MAC) could be reciprocally related to large potentiation of other inhibitory ion channels. If so, then reduced glycine receptor potency should increase NMDA receptor antagonism by sevoflurane at MAC.MethodsIndwelling lumbar subarachnoid catheters were surgically placed in 14 anesthetized rats. Rats were anesthetized with sevoflurane the next day, and a pre-infusion sevoflurane MAC was measured in duplicate using a tail clamp method. Artificial CSF (aCSF) containing either 0 or 4 mg/mL strychnine was then infused intrathecally at 4 μL/min, and the post-infusion baseline sevoflurane MAC was measured. Finally, aCSF containing strychnine (either 0 or 4 mg/mL) plus 0.4 mg/mL dizocilpine (MK-801) was administered intrathecally at 4 μL/min, and the post-dizocilpine sevoflurane MAC was measured.ResultsPre-infusion sevoflurane MAC was 2.26%. Intrathecal aCSF alone did not affect MAC, but intrathecal strychnine significantly increased sevoflurane requirement. Addition of dizocilpine significantly decreased MAC in all rats, but this decrease was two times larger in rats without intrathecal strychnine compared to rats with intrathecal strychnine, a statistically significant (P < 0.005) difference that is consistent with increased NMDA receptor antagonism by sevoflurane in rats receiving strychnine.ConclusionsGlycine receptor antagonism increases NMDA receptor antagonism by sevoflurane at MAC. The magnitude of anesthetic effects on a given ion channel may therefore depend on the magnitude of its effects on other receptors that modulate neuronal excitability.
Topical morphine promoted corneal analgesia for up to 4 days and did not delay corneal re-epithelization. The re-establishment of MMPs and IL-10 to levels close to baseline values at the end of the study and the expression of type IV collagen in both groups reinforce that, with caution, 1% morphine can be used after lamellar keratectomy in rabbits.
To evaluate the cardiorespiratory changes induced by isoflurane (ISO) anesthesia in the crested caracara (Caracara plancus), eight crested caracaras that weighed 1.0 kg (range 0.9-1.1 kg) were the subjects for the study. The birds were anesthetized by face mask with ISO for brachial artery catheterization. After recovery, anesthesia was re-induced and maintained with ISO with spontaneous ventilation. Electrocardiography, direct systolic arterial blood pressure (SAP), diastolic arterial blood pressure (DAP), mean arterial blood pressure (MAP), respiratory rate (RR), end-tidal carbon dioxide (P(ET)CO2), and cloacal temperature (T degrees C) were measured before induction (baseline, under physical restraint) and after 5, 10, 15, 20, 25, 30, 35, and 40 min of ISO anesthesia. Arterial blood samples were collected for blood gas analysis at baseline, 10, 25, and 40 min. No cardiac arrhythmias were observed in the present study. RR, SAP, DAP, MAP, T degrees C and pH decreased from baseline values, whereas arterial partial pressures of oxygen and carbon dioxide, bicarbonate concentration, and P(ET)CO2 were significantly higher than baseline. Apnea was not observed in any bird. ISO anesthesia is suitable for use in healthy members of this species despite the moderate cardiovascular and respiratory depression produced.
Avaliaram-se os efeitos do fornecimento de diferentes frações inspiradas de oxigênio (FiO2) sobre a dinâmica respiratória em cães submetidos a infusão contínua de propofol e mantidos em ventilação espontânea. Oito cães foram submetidos a cinco anestesias diferenciando uma da outra pela FiO2 fornecida. Formaram-se cinco grupos denominados G100 (FiO2 = 1), G80 (FiO2 = 0,8), G60 (FiO2 = 0,6), G40 (FiO2 = 0,4) e G20 (FiO2 = 0,21). Os animais foram induzidos à anestesia com propofol na dose necessária para intubação, e ato contínuo iniciou-se a infusão do fármaco e o fornecimento de oxigênio conforme a FiO2 determinada para cada grupo. As primeiras mensurações foram efetuadas 30 minutos após o início da infusão do anestésico (M0), em seguida em intervalos de 15 minutos (M15, M30, M45 e M60). Os dados numéricos obtidos foram submetidos a Análise de Variância, seguida pelo teste Tukey (p<0,05). Os valores registrados de saturação de oxihemoglobina (SpO2) e SaO2 foram significativamente menores para G20, enquanto que a pressão parcial de oxigênio no sangue arterial (PaO2) variou conforme a fração de oxigênio fornecida. Para a pressão parcial de dióxido de carbono no sangue arterial (PaCO2) foram registradas diferenças em M30, no qual G100 apresentou médias superiores a G20. Conclui-se que o fornecimento de oxigênio a 100%, 80% e 21% devem ser evitados, pois proporciona prejuízos significativos ao sistema respiratório de cães anestesiados com infusão contínua de propofol na dose de 0,7mg/kg/min sob ventilação espontânea.
Chrysocyon brachyurus (maned wolf) is the biggest South American canid and has a high frequency of dental injuries, both in the wild and in captivity. Thus, veterinary procedures are necessary to preserve the feeding capacity of hundreds of captive specimens worldwide. The aim of this study was to investigate the mandibular morphometry of the maned wolf with emphasis on the establishment of anatomic references for anesthetic block of the inferior alveolar and mental nerves. Therefore, 16 measurements in 22 mandibles of C. brachyurus adults were taken. For extraoral block of the inferior alveolar nerve at the level of the mandibular foramen, the needle should be advanced close to the medial face of the mandibular ramus for 11.4 mm perpendicular to the palpable concavity. In another extraoral approach, the needle may be introduced for 30.4 mm from the angular process at a 20-25° angle to the ventral margin. For blocking only the mental nerve, the needle should be inserted for 10 mm from ventral border, close to the labial surface of the mandibular body, at the level of the lower first premolar. The mandibular foramen showed similar position, size, and symmetry in the maned wolf specimens examined. Comparison of the data observed here with those available for other carnivores indicates the need to determine these anatomic references specifically for each species.
RESUMOA técnica de analgesia multimodal, por meio da infusão contínua de fármacos, pode ser empregada para diminuir a incidência de sensibilização central durante a anestesia. Avaliaram-se as características cardiorrespiratórias, durante o procedimento de artroscopia de joelho, em cães anestesiados com isofluorano e monitorados por meio do índice biespectral, submetidos à infusão contínua de morfina ou fentanil, associada à lidocaína e cetamina. Utilizaram-se 16 cães adultos, machos ou fêmeas, os quais foram distribuídos aleatoriamente em dois grupos, denominados MLK que recebeu morfina (3,3μg/kg/min), lidocaína (50μg/kg/min) e cetamina (10μg/kg/min) ou FLK -em que foi substituída a morfina pelo fentanil (0,03μg/kg/min). Os cães foram pré-tratados com levomepromazina (0,5mg/kg IV), induzidos à anestesia com propofol (5mg/kg) e mantidos com isofluorano, ajustando-se a concentração para obterem-se valores de índice biespectral entre 55 e 65. As mensurações da frequência cardíaca (FC), dos parâmetros eletrocardiográficos (ECG), das pressões arteriais sistólica (PAS), diastólica (PAD) e média (PAM), da tensão de dióxido de carbono expirado (EtCO 2 ), da saturação de oxi-hemoglobina (SpO 2 ), da frequência respiratória (FR) e da temperatura esofágica (T) iniciaram-se 30 minutos após a indução (M0) e continuaram após o início da infusão das soluções, em intervalos de 15 minutos (M15 a M75). Diferenças entre os grupos foram registradas para duração do complexo QRS (M60), para FC e T, entre M30 e M75, com MLK apresentando médias maiores que FLK, que registrou médias maiores que MLK para a SpO 2 (M60), para os intervalos QT (M30 e M75) e RR (M0, M60 e M75). Concluiu-se que o emprego de morfina ou fentanil, associados à lidocaína e cetamina, promove efeitos semelhantes e não compromete as características avaliadas.
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