Padronização da anestesia em suínos para procedimentos cirúrgicos cardiovasculares experimentais / Standardization of anesthesia in swine for experimental cardiovascular surgeries / Estandarización de la anestesia en cerdos para procedimientos quirúrgicos cardiovasculares experimentales

JUSTIFICATIVA E OBJETIVO: Embora sejam os cães os animais mais utilizados em Cirurgia Experimental, nota-se crescente utilização de ovinos, bovinos e suínos como modelos para experimentação científica. Assim, faz-se necessário maior aprendizado de seu tratamento e padronizações básicas para os procedimentos cirúrgicos mais complexos em suínos. O objetivo foi avaliar a sedação e analgesia, obtidas pela injeção intramuscular de midazolam e cetamina e anestesia local com lidocaína a 2 por cento sem vasoconstritor, na realização de traqueostomia, dissecção de artéria e veia femorais. MÉTODO: A freqüência cardíaca e o reflexo córneo-palpebral foram avaliados logo no início da sedação, durante os procedimentos cirúrgicos descritos e após seu término. Foram utilizados oito suínos fornecidos por fazendas locais sem tratamento prévio da raça Large White, com peso de 35 a 42 quilos que receberam injeção intramuscular de 22 mg.kg-1 de cetamina e 0,3 mg.kg-1 de midazolam. RESULTADOS: A abordagem anestésica nesses animais, de difíceis intubação e acesso aos vasos profundos, provou ser segura para sedação e analgesia através do método utilizado: acesso intramuscular. CONCLUSÃO: Obteve-se adequado plano de anestesia para o procedimento proposto.

BACKGROUND AND OBJECTIVES: Although dogs are the animals used more often in Experimental Surgeries, the use of sheep, bovine, and swine as models for scientific experiments has been growing. Thus, further learning on the treatment and basic standardization of more complex surgeries in swine are necessary. The objective of this study was to evaluate sedation and analgesia, obtained by the intramuscular administration of midazolam and ketamine, and local anesthetics with 2 percent lidocaine without vasoconstrictor, in tracheostomy and dissection of femoral artery and vein. METHODS: The heart rate and corneal-palpebral reflex were evaluated at the beginning of sedation, during the surgical procedures, and at the end of those procedures. Eight Large White swine, without prior treatment, weighing 35 to 42 kg were provided by local farms. They received intramuscular injections of 22 mg.kg-1 of ketamine and 0.3 mg.kg-1 of midazolam. RESULTS: The anesthetic approach on those animals, who present both difficult intubation and access to deep vessels, proved to be safe for sedation and analgesia by the method chosen: intramuscular administration. CONCLUSIONS: An adequate plane of anesthesia for the proposed procedure was achieved.

JUSTIFICATIVA Y OBJETIVOS: Aunque los perros sean los animales más a menudo usados en Cirugía Experimental, se nota un aumento en la utilización de los ovinos, bovinos y porcinos como modelo para experimentación científica. De esa forma, se hace necesario aprender más con su tratamiento y estandarizaciones básicas para los procedimientos quirúrgicos más complejos en porcinos. El objetivo fue evaluar la sedación y la analgesia obtenidas por la inyección intramuscular de midazolán y la cetamina y anestesia local con lidocaína a un 2 por ciento sin vasoconstrictor, en la realización de traqueostomía, disección de arteria y vena femorales. MÉTODO: La frecuencia cardíaca y el reflejo córneo-palpebral fueron evaluados inmediatamente al inicio de la sedación, durante los procedimientos quirúrgicos descritos y después en su conclusión. Se utilizaron ocho porcinos que fueron suministrados por haciendas de la región sin tratamiento previo de la raza Large White, con peso de 35 a 42 kilos que recibieron inyección intramuscular de 22 mg.kg-1 de cetamina y 0.3 mg.kg-1 de midazolán. RESULTADOS: El abordaje anestésico en esos animales, de difícil intubación y acceso a los vasos profundos, demostró ser seguro para la sedación y analgesia a través del método utilizado: el acceso intramuscular. CONCLUSIÓN: Se obtuvo un adecuado plan de anestesia para el procedimiento propuesto.

Effect of Supine or Jack-knife Position on the Arterial O2, CO2 Tension, Respiratory Rate and Oxygen Saturation Following Midazolam Sedation for Spinal Anesthesia / 대한마취과학회지

BACKGROUND: Anorectal procedures are performed in the jack-knife position. The combined use of midazolam and spinal anesthesia is common in clinical practice. Despite the known potential for each to alter ventilation, the effect of their interaction under jack-knife position has not been examined. METHODS: In a prospective, double-blind, and randomized study, forty patients (four groups, n=10 each, saline-supine position group, saline-jack-knife position group, midazolam-supine position group and midazolam-jack-knife position group) were examined. The effect of intravenous midazolam (0.05 mg/kg) for sedation, spinal anesthesia (hyperbaric tetracaine, below T8), position (jack-knife position or supine position during operation), and their combination on mean arterial pressure, arterial oxygen saturation (SpO2), PaO2, PaCO2, respiratory rate were evaluated. Incidence of hypoxemia was measured by pulse oximetry (SpO2 less than 90% for 30 seconds or longer). RESULTS: The incidence of hypoxemia in the midazolam-supine position group was 20%. There was no patient showing hypoxemia in other groups. After spinal anesthesia, there were no significant differences of mean arterial pressure, arterial oxygen saturation, PaO2, PaCO2, respiratory rate between supine and jack-knife position. The combination of jack-knife position and midazolam caused a significant increase of PaCO2 (9% of baseline value). Cardiovascular side effects such as hypotension or other reactions such as vomiting, nausea, or confusion were not observed after midazolam. At the end of the operation, all patients were fully awake and cooperative. CONCLUSIONS: Intravenous midazolam (0.05 mg/kg) may produce hypoxemia (SpO2<90%) during spinal anesthesia in supine position. In the jack-knife position, intravenous midazolam caused increase of the arterial CO2 tension. Monitoring of arterial blood oxygen saturation is mandatory in patients with spinal anesthesia and midazolam sedation during supine position.