No description available.

Diss. Linköping : Univ., 2004.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of the present study was to determine the duration and efficacy of local analgesia produced by bupivacaine, lidocaine and ropivacaine used to block the palmar digital (PD) nerve. Nine adult horses underwent a thorough physical examination and evaluation using wireless motion sensors to determine the absence of signs of lameness. Galvanized steel clamps were used to induce lameness. The horses were randomly allocated in a crossover design (bupivacaine 7,5 mg/ml, lidocaine 30 mg, ropivacaine 11,25 mg). The objective lameness evaluations were recorded immediately before administration of the anesthetic on the digital palmar nerve, and then at 5, 10, 15, 30, 60, 90,120, 150, 180, 210, 240 and 300 minutes after the block. The evaluation of mean improvement in lameness after the block was performed using the Wilcoxon test (P> 0.05). The relative lameness severity (RLS) observed after the induction of lameness was 2,4 times the threshold (6mm) and the intensity of the induced lameness was similar between horses (coefficient of variance = 55,26%). Bupivacaine, lidocaine and ropivacaine were effective in blocking at least 75% of the lameness induced by clamps, 5 minutes after the block, the tested drugs improved more than 60% of the lameness. With 7.5 mg bupivacaine improved lameness in more than 90% between 10 and 60 minutes after blocking. Lidocaine (30 mg), resulted in maximal analgesia between 10 and 30 minutes after blocking and the lameness improvement was higher than 69%. Administration of 11.25 mg ropivacaine was able to improve lameness more than 86% between 10 and 180 minutes. The doses of bupivacaine and ropivacaine used in this study were effective in blocking lameness induced by clamps. The dose of 30 mg of lidocaine was not able to completely reverse the lameness. At 5 minutes of blocking, the local anesthetics tested had produced a significant improvement in lameness. Objective analysis of lameness showed a longer analgesic effect on the PD nerve block using ropivacaine than bupivacaine and lidocaine. / O objetivo deste estudo foi avaliar o início, a duração e a eficácia da analgesia local produzida pela lidocaína, bupivacaína e ropivacaína no bloqueio do nervo digital palmar. Foram selecionados nove cavalos adultos submetidos a exame físico e avaliação utilizando sensores inerciais para avaliar a ausência de sinais de claudicação. Braçadeiras de aço galvanizado foram utilizadas para induzir claudicação. Os cavalos foram alocados aleatoriamente em um modelo crossover (bupivacaína 7,5 mg, lidocaína 30 mg, ropivacaína 11,35 mg). As análises objetivas de claudicação foram registradas antes da administração perineural dos fármacos no nervo digital palmar e em seguida aos 5, 10, 15, 30, 60, 90,120, 150, 180, 210, 240 e 300 minutos após o bloqueio. A avaliação das médias de estimativa de melhora da claudicação após o bloqueio foi realizada através do teste de Wilcoxon (P>0,05). A severidade da claudicação relativa (SCR) observada após a indução de claudicação foi 2,4 vezes o limiar (6 mm) e a intensidade da claudicação induzida foi semelhante entre os cavalos (coeficiente de variação = 55,26%). Bupivacaína, lidocaína e ropivacaína foram eficientes em bloquear acima de 75% da claudicação induzida experimentalmente, 5 minutos após o bloqueio todas as drogas testadas apresentavam melhora na claudicação superior a 60%. Utilizando 7,5 mg de bupivacaína a estimativa de melhora na claudicação foi superior a 90% entre 10 e 60 minutos após o bloqueio. Com 30 mg de lidocaína a analgesia máxima ocorreu entre 10 e 30 minutos após o bloqueio e a estimativa de melhora na claudicação foi superior a 69%. A administração de 11,25 mg de ropivacaína bloqueou a claudicação em mais de 86%, entre 10 e 180 minutos após o bloqueio. As doses de bupivacaína e ropivacaína utilizadas neste estudo foram eficientes em bloquear a claudicação induzida por braçadeiras. A dose de 30 mg de lidocaína não foi eficiente em bloquear totalmente a claudicação. Cinco minutos após o bloqueio todos os anestésicos locais apresentavam melhora na estimativa de claudicação. As análises objetivas de claudicação mostraram efeito analgésico mais longo no bloqueio do nervo digital palmar da ropivacaína do que da bupivacaína e lidocaína.

This study aimed to investigate the use of local infiltrative anesthesia with 0.5% bupivacaine in surgical incision site as part of a multimodal analgesic approach in dogs submitted to ovariohysterectomy (OVH) by celiotomy or video-assisted by two-port. Twenty-eight adult (2.08 ± 1.45 years) and healthy bitches, weighing 12.67 ± 1.94 kg, with aptitude confirmed by clinical and laboratory tests were selected. Dogs were pre-medicated with acepromazine (0.05mg.kg-1, IM), induced and maintained in general anesthesia with propofol (4mg.kg-1, IV) and isoflurane vaporized in 100% oxygen, respectively. Intraoperative analgesia was promoted with fentanyl in continuous infusion (20μg.kg -1.hour-1), preceded by a loading dose (2,5μg.kg-1, IV). Dogs were divided into four groups: control group celiotomy (CC, n = 7), blocking group celiotomy (BC, n = 7), control video-assisted group (CV) and blocking video-assisted group (BV). In the blocked groups (BC and BV), bupivacaine (2mg.kg-1) was administered subcutaneously in the incision line or port entry sites. Control groups received 3 ml of saline solution at the same sites. Meloxicam (0.2mg.kg-1) administered at the end of the surgery with the combination of metamizole sodium and Hyoscine N-butyl bromide every 8 hours for 2 days. Postoperative pain was evaluated by three evaluators blinded to surgery and treatment established, using Melbourne Pain Scale and visual analogue scale. Pain was assessed hourly in the first 8 hours and, then, at 12, 18, 24, 36 and 48 hours post-extubation. Glycemia and serum cortisol were evaluated too. Rescue analgesia was administered to one animal in CV after one hour postoperative, while seven dogs in CC received additional analgesia in the first two hours postoperative and was not required by any of the animals that received anesthetic block (BC and BV). Statistical analysis suggested that the anesthetic infiltrative blockade performed with 2,0mg.kg-1 bupivacaine was efficient in promoting postoperative comfort when used in both celiotomy and video-assisted OVH.. / Este estudo objetivou avaliar o uso de anestesia local infiltrativa com bupivacaína a 0,5% na área da incisão cirúrgica como parte de uma abordagem analgésica multimodal em cães submetidos à ovariohisterectomia (OVH) por celiotomia ou vídeo-assistida por dois portais. Para isso foram selecionadas vinte e oito cadelas adultas (2,08±1,45 anos) hígidas, pesando 12,67±1,94kg. Os animais foram pré medicados com maleato de acepromazina (0,05mg.kg-1, IM), anestesiados com propofol (4mg.kg-1, IV), seguida de manutenção da anestesia geral com isoflurano vaporizado em oxigênio a 100%. A analgesia transoperatória foi promovida com fentanil em infusão contínua (20μg.kg-1 hora-1), precedida de dose bolus (2,5μg.kg-1, IV). Os animais foram alocados aleatoriamente em quatro grupos: grupo controle celiotomia (CC, n=7), grupo bloqueio celiotomia (BC, n=7), grupo controle vídeo-assistido (CV, n=7), e grupo bloqueio vídeo-assistido (BV, n=7). Nos grupos em que foi realizado bloqueio (BC e BV), a bupivacaína a 2mg.kg-1 foi administrada por via subcutânea na linha de incisão ou na entrada dos portais. Nos grupos controle, foi infiltrado 3 ml de solução salina nos mesmos locais. Foi administrado meloxicam (0.2mg.kg-1) ao final da cirurgia e a c formulação comercial de metamizol sódico e hioscina N-butilbromida a cada 8 horas durante dois dias. Todos os animais tiveram a dor pós-operatória avaliada por três avaliadores experientes e cegos para o tratamento e cirurgia, usando as escalas de dor de Melbourne e visual analógica a cada hora nas primeiras 8 horas e às 12, 18, 24, 36 e 48 horas após a extubação. A glicemia e o cortisol sérico também foram avaliados. Não houve resgate analgésico em nenhum dos animais de grupos que receberam bloqueio anestésico (BC e BV). Em todos os animais do CC e um em CV receberam resgate analgésico até a segunda hora de pós-operatório. O bloqueio infiltrativo anestésico realizado com 2,0mg.kg-1 de bupivacaína foi eficiente na promoção do conforto pós-operatório quando utilizado em OVH por celiotomia e vídeoassistidas.

Orientador: Cesar Costapinto Santana / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-07T06:44:05Z (GMT). No. of bitstreams: 1 SilvaJunior_IvanildoJoseda_M.pdf: 3837238 bytes, checksum: 02f8a9f82e58c32dd06267574565ddda (MD5) Previous issue date: 2006 / Resumo: Este trabalho teve por objetivo a determinação de parâmetros cromatográficos envolvidos na separação dos enantiômeros do anestésico bupivacaína, visando sua utilização no projeto de uma unidade cromatográfica do tipo leito móvel simulado (LMS) com colunas quirais ,O'-bis[4-terc-buitilbenzoil]-N,N'-dialil-L-tartadiamida e exano/2- propanol/ácido acético/trietilamina (98/2/0,3/0,05 v/v) como fase móvel. Os experimentos para determinação dos parâmetros foram realizados em uma única coluna, divididos em dois conjuntos de ensaios utilizando soluções diluídas e soluções concentradas. Experimentos de pulsos com soluções diluídas dos traçadores e dos enantiômeros da bupivacaína foram realizados variando a vazão de 1,0 a 4,0 mL/min e às temperaturas de 25, 35 e 45 ºC. A detecção foi realizada no comprimento de onda de 270 nm com a finalidade de determinar as porosidades do sistema, as constantes de equilíbrio de adsorção sob condições lineares das isotermas (coeficientes de Henry), os coeficientes de dispersão axial e parâmetros de transferência de massa. Os cromatogramas mostraram que os perfis apresentam baixa dispersão e que a coluna apresenta uma alta eficiência de separação com valores de número de pratos superiores a 5000, para vazão de 1,0 mL/min. Os valores dos coeficientes de Henry foram maiores que a unidade para ambos enantiômeros, sendo que o enantiômero mais retido, S-(-)-bupivacaína, apresentou maior afinidade pela coluna quiral com maiores valores dos coeficientes de Henry. Parâmetros termodinâmicos confirmaram a maior afinidade da S-(-)-bupivacaína pela coluna com maiores valores negativos de entalpia de adsorção ( ?H0). Os coeficientes de transferência de massa globais apresentaram valores com alta ordem de magnitude aumentando com a elevação da temperatura. Os valores do coeficiente de transferência de massa foram superiores a 150 min-1 para temperatura de 25 ºC. A alta eficiência de separação deve-se, provavelmente, à rápida taxa de transferência de massa em que os processos convectivos são dominantes. Experimentos a altas concentrações (condições de sobrecarga) foram realizados com a finalidade de se determinar às isotermas competitivas não-lineares pelo método da análise frontal e também os perfis de eluição sob estas condições. As isotermas de adsorção competitivas apresentaram comportamento não-linear para a faixa de concentração utilizada e foram satisfatoriamente ajustadas ao modelo de Langmuir competitivo. Os parâmetros termodinâmicos de adsorção lineares e de transferência de massa foram utilizados para o projeto das condições operacionais da unidade LMS pela metodologia dos volumes de separação. As regiões de separação foram calculadas em que foram observadas reduções significativas nas regiões de separação com a imposição dos efeitos não-ideais. A predição de separação foi realizada pelas abordagens do leito móvel verdadeiro e do leito móvel simulado, a partir de soluções numéricas utilizando os modelos do transporte dispersivo e do equilíbrio dispersivo, respectivamente. Em ambas abordagens, os parâmetros de desempenho (pureza, produtividade e consumo de solvente) apresentaram resultados próximos / Abstract: The aim of this work was the determination of chromatographic parameters in the enantiomeric separation of anesthetic bupivacaine and design the chromatographic separation in a simulated moving bed (SMB), using 0,0'-bis[4-tert-butylbenzoyl]-N,N'- dialyl-L-tartadiamide as chiral columns and hexane/2-propanol/acetic acid/trietylamine (98/2/0,3/0,05 v/v) as mobile phase. The experiments were performed using a single column and were divided in two sets using dilute and concentrated solutions. Pulse experiments with dilute solutions of inert compounds and the bupivacaine enantiomers were accomplished at different flow rates (1.0 to 4.0 mL/min) and temperatures (25, 35 and 45 ºC). The peak responses were monitored at 270 nm. The integration of the responses gave information about the porosities, linear equilibrium adsorption constants (Henry constants), axial dispersion and mass transfer coefficients. The chromatograms showed low dispersion and high separation efficiency with 5000 plate number to the flow-rate of 1.0 mL/min.The more retained enantiomer, S-(-)-bupivacaine, has more affinity for the chiral column with higher values of Henry constants than the less retained enantiomer. Hermodynamics parameters confirm the major affinity of S-(-)- bupivacaine with high negative values of adsorption enthalpy ( ?H0). The overall mass transfer coefficient increased with increase in temperature and achieved values of high order of magnitude about 150 min-1 at 25 ºC. The high efficiency observed is probably due to the fast mass transfer which is dominating by convective effects. Experiments in overloaded conditions were realized in order to obtain the competitive equilibrium adsorption isotherms by frontal analysis, as well overload elution profiles. The competitive isotherms shown a nonlinear behaviour to the range of concentration investigated and the Langmuir competitive model represent satisfactorily the adsorption data. The linear equilibrium constants and mass transfer parameters were used to design the operating conditions in a SMB unit by separation volumes methodology. The separation regions were obtained concerning the resistances of mass transfer. It was observed a significant reduction in the separation region for different mass transfer coefficients and purity requirement. The prediction of the chromatographic SMB separation for linear conditions was performed using simulated moving bed approach and true moving bed approach (TMB). In SMB approach was used equilibrium dispersive mathematical model and for TMB approach the transport dispersive mathematical model. For these approaches, the performance parameters (purity, productivity and solvent consumption) showed practically the same values / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

Magister Scientiae - MSc / The purpose of this research project was to assess the safety and efficacy of a combination of drugs for conscious sedation in patients undergoing office-based plastic and reconstructive surgery. A pilot study was done to determine the safety of the co-administration of the drugs used in the sedation technique. / South Africa

Le syndrome douloureux régional complexe (SDRC) est un trouble neurologique qui se caractérise par des douleurs intenses, des troubles vasomoteurs, sudomoteurs, moteurs et trophiques, accompagnés d’un œdème au niveau du membre affecté. Malgré la présence de peu de données en faveur, à cause de l’absence d’un traitement clé du SDRC, le blocage sympathique a été utilisé depuis de nombreuses années pour traiter ce syndrome. Objectif Le but principal de ce projet est d’étudier l’effet antalgique de la néostigmine utilisée comme adjuvant à la bupivacaïne lors d’un bloc stellaire dans le traitement du syndrome douloureux régional complexe du membre supérieur. Méthodes Il s’agit d’une étude pilote, randomisée en double insu. L’intensité de la douleur a été évaluée en utilisant l’échelle numérique. La force de préhension aux deux mains a été estimée par dynamométrie de Jamar. La dextérité fine des doigts a été mesurée par le « Purdue Pegboard Test ». L’œdème au niveau de la main a été déterminé par la volumétrie. Le questionnaire « SF-36 » a été utilisé afin de déterminer l’homogénéité des échantillons. Résultats Notre étude a eu des difficultés à établir l’efficacité de la thérapie par bloc stellaire dans le traitement du syndrome douloureux régional complexe. Conclusion Notre recherche n’a pu prouver l’hypothèse que le traitement de la douleur dans le SDRC du membre supérieur par un bloc stellaire est plus efficace quand l’action de l’anesthésique local est potentialisée par l’ajout de la néostigmine. / Complex regional pain syndrome (CRPS) is a neurological disorder characterized by severe pain, vasomotor, sudomotor, motor and trophic changes, accompanied by a swelling in the affected limb. Despite the limited data on his efficiency, in the absence of a definite curative treatment of the CRPS, sympathetic blocks have been used for years to treat the syndrome. Objective The main purpose of this project was to investigate the analgesic effect of neostigmine used as an adjuvant to the local anaesthetic bupivacaine in stellate ganglion blockade, in treating CRPS of the upper limb. Methods This was a pilot, randomized, double-blind study. The intensity of the pain was evaluated using a numeric scale. Grip strength in both hands was estimated by Jamar dynamometry. Fine finger dexterity was measured by the "Purdue Pegboard Test." The swelling in the hand was determined by volumetry. The questionnaire "SF-36" was used to determine the homogeneity of the samples in terms of quality of life assessment. Results Our study had difficulties in establishing the efficiency of stellate ganglion blockade in the treatment of complex regional pain syndrome. Conclusion This research project has not been able to prove that the pain treatment in upper limb CRPS by means of stellate ganglion blockade is more effective when the action of the local anesthetic is potentiated by the addition of neostigmine.

O objetivo deste estudo foi comparar a eficácia anestésica da articaína 4%, da lidocaína 2%, ambas associadas à epinefrina 1:100.000, e da bupivacaína 0.5%, associada à epinefrina 1:200.000, durante pulpectomia em pacientes com pulpite irreversível em molares inferiores. Cento e cinco voluntários do Setor de Urgência da Faculdade de Odontologia da Universidade de São Paulo receberam, aleatoriamente, 3,6mL de um dos anestésicos locais para o convencional bloqueio do nervo alveolar inferior (BNAI). No caso de falha do BNAI, foram administrados 3,6mL da mesma solução como injeção complementar no ligamento periodontal. O sinal subjetivo de anestesia do lábio, a presença de anestesia pulpar e ausência de dor durante a pulpectomia foram avaliados, respectivamente, por indagação ao paciente, por meio do aparelho estimulador pulpar elétrico (pulp tester) e por uma escala analógica verbal. A análise estatística foi realizada por meio dos testes Qui-quadrado, Kruskal Wallis e Razão de Verossimilhanças. Foi adotado nível de significância de 0,05 (P <= 0,05). Todos os pacientes reportaram anestesia no lábio após o BNAI. A lidocaína apresentou valores superiores (42,9%) para a anestesia pulpar após o BNAI e após a injeção no ligamento periodontal (61,5%). A bupivacaína apresentou valores superiores para a analgesia (80%) após o BNAI e a lidocaína (92,3%) após a injeção no ligamento periodontal. Após a falha do BNAI, a dor na câmara pulpar foi a mais frequente para articaína e lidocaína e na dentina para a bupivacaína e após a falha da injeção no ligamento periodontal, a dor foi similar para articaína nas diferentes regiões; câmara, canal e dentina; para a bupivacaína foi mais frequente na dentina e para a lidocaína no canal. No entanto, essas diferenças não foram estatisticamente significantes. Portanto as três soluções anestésicas locais se comportam de forma semelhante e não apresentam efetivo controle da dor no tratamento da pulpite irreversível em molares inferiores. / The aim of this study was to compare the anesthetic efficacy of 4% articaine and 2% lidocaine both associated with 1:100,000 epinephrine and 0.5% bupivacaine associated with 1:200,000 epinephrine in patients with irreversible pulpitis of the mandibular molars during a pulpectomy procedure. One hundred and five volunteers from the Emergency Center of the School of Dentistry at University of São Paulo randomly received 3.6 mL of local anesthetic as a conventional inferior alveolar nerve block (IANB). The subjective signal of lip numbness, pulpal anesthesia and the absence of pain during the pulpectomy procedure were, respectively, evaluated by questioning the patient, stimulation using an electric pulp tester and a verbal analogue scale. Statistical analysis was performed using the chi-square test, Kruskal Wallis and likelihood rations. The level for significance of differences was P <= .05. All patients reported the subjective signal of lip numbness after the application of either IANB. Lidocaine showed higher values for pulpal anesthesia after the IANB (42.9%) and after injection in the periodontal ligament (61.5%). Bupivacaine presented higher values for analgesia after the IANB (80,0%) and lidocaine after injection in the periodontal ligament (92,3%). After the failure of the IANB, the pain in the pulp chamber was the most frequent to articaine and lidocaine and bupivacaine for dentin and after the failure of the periodontal ligament injection, the pain was equal to articaine in different regions, chamber, canal and dentin; for bupivacaine was greater in dentin and lidocaine was higher in the channel. However, these differences were not statistically significant. So the three local anesthetic solutions behave similarly and not present any effective pain control in the treatment of irreversible pulpitis in mandibular molars.

Este é um estudo clínico, prospectivo, aleatório, e duplamente encoberto realizado em 40 crianças submetidas a cirurgia infra-umbilical de pequeno porte, sob anestesia epidural sacra realizada com a mistura enantiomérica de bupivacaína (S75R25) comparada com a bupivacaína racêmica (SR50) isoladas ou em associação com a clonidina. O objetivo foi avaliar a duração do bloqueio motor e sensitivo, o consumo de sevoflurano e as variações da pressão arterial sistólica (PAS) e freqüência cardíaca (FC). O bloqueio motor foi avaliado pela escala de Bromage, durante o período de oito horas de observação no pós-operatório. A analgesia foi avaliada pelos escores obtidos com escala objetiva para análise da dor e a duração da analgesia foi considerada como o tempo entre a administração do anestésico local no espaço epidural sacro e a primeira dose de analgésico administrado. Os resultados obtidos foram submetidos à análise estatística onde p< 0,05 foi considerado significante. Os resultados mostraram que houve aumento significativo do bloqueio motor somente na primeira hora quando a bupivacaína SR50 foi associada a clonidina, mas não ocorreu o mesmo com a bupivacaína S75R25. Em relação a analgesia não houve diferença significante entre a bupivacaína SR50 e a bupivacaína S75R25 associadas ou não à clonidina. Não houve diferença significativa no consumo de sevoflurano entre os grupos estudados quando a clonidina foi associada aos anestésicos. Os valores da PAS e FC no pós-operatório, nos grupos onde a clonidina foi associada com ambos anestésicos locais, foram inferiores em todos os momentos de avaliação, porém sem significância estatística / This is a prospective, randomized double-blind clinical trial performed in 40 children using an enantiomeric mixture of bupivacaine (S75R25) compared to racemic bupivacaine SR50 plain or associated with clonidine, to caudal blockade. The aim of this study was to investigate the motor and sensitive block, sevoflurane requirement, blood pressure (PAS) and heart rate (FC) in children scheduled to sub-umbelical surgeries. The motor block was evaluated by Bromage scale for eight hours during the postoperative period. The analgesia was evaluated postoperatively for eight hours by an objective pain scale and the analgesia duration was taken as the time between the local anesthetic administration into epidural space and the first analgesic rescue. The results obtained were submitted to statistical analysis test where p< 0,05 was considered significant. There was a significant increase in the motor block at first hour on postoperative period when bupivacaine SR50 was associated to clonidine, but it did not occurr with the enantiomeric mixture of bupivacaine S75R25. There was no difference between bupivacaine SR50 and bupivacaine S75R25 associated or not to clonidine regarding to analgesia duration. There was no difference in the requirement of sevoflurane between groups in spite of the clonidine admixture to the local anesthetics. There was an absolut decrease in the PAS and FC values on the postoperative evaluation, but it was not statistically significant

I found that 2.6ml of 0.5% levobupivacaine had similar clinical characteristics as the same volume of 0.5% bupivacaine in spinal anaesthesia. Both were effective for spinal anaesthesia in urological surgery, when a sensory block up to at least T10 dermatome was required. In comparing the use of levobupivacaine alone and levobupivacaine with fentanyl, there were no significant differences in haemodynamic changes and quality of sensory and motor block, when 2.6ml of levobupivacaine alone or 2.3ml of levobupivacaine with fentanyl 15mcg (0.3ml) were used in spinal anaesthesia. Both were effective for spinal anaesthesia in urological surgery. In comparing the use of ropivacaine 10mg and bupivacaine 10mg, both with fentanyl 15mcg in spinal anaesthesia for urological surgery, all the patients achieved adequate level of sensory block up to T10 dermatome or higher. The two drugs were similar in the onset time of motor block, the characteristics of sensory block and haemodynamic changes; however, the duration of motor block was shorter with ropivacaine. I concluded that both studied solutions, ropivacaine-fentanyl and bupivacaine-fentanyl, were effective for spinal anaesthesia in urological surgery and the duration of motor block was shorter with the ropivacaine-fentanyl solution. The dose-response relationship of ropivacaine in spinal anaesthesia for lower limb surgery requiring a sensory block up to at least the T12 dermatome was defined. Anaesthesia was successful in 0, 0, 42, 83 and 100% when ropivacaine at doses of 2, 4, 7, 10 and 14mg respectively were given. The derived values for ED50 and ED95 were 7.6mg and 11.4mg respectively. The cephalic level of sensory block and the degree of motor block increased with larger doses of ropivacaine. Finally, the median effective dose (ED50) of bupivacaine, levobupivacaine and ropivacaine in spinal anaesthesia for lower limb surgery were defined as 5.50mg (95% CI: 4.90--6.10mg), 5.68mg (95% CI: 4.92--6.44mg), and 8.41mg (95% CI: 7.15--9.67mg) respectively. The relative potency ratios were 0.97 (95% CI: 0.81--1.17) for levobupivacaine/bupivacaine, 0.65 (95% CI: 0.54--0.80) for ropivacaine/bupivacaine and 0.68 (95% CI: 0.55--0.84) for ropivacainellevobupivacaine. / In this series of studies, I have shown that levobupivacaine and ropivacaine are effective local anaesthetic agents for spinal anaesthesia in lower limb and urological surgery. This proved my hypothesis. Both are suitable alternatives to bupivacaine for spinal anaesthesia. Furthermore, these studies showed that ropivacaine is less potent than levobupivacaine and bupivacaine and the potency is similar between levobupivacaine and bupivacaine at median effective dose. / Levobupivacaine and ropivacaine are two relatively new local anaesthetics which were developed in view of their potential for less cardiotoxicity in comparison with bupivacaine, the most common local anaesthetic used in spinal anaesthesia for many years. Both are produced in pure S(-) enantiomer form in contrast to bupivacaine which is a racemic mixture. They have been shown to be effective in peripheral nerve blocks, and epidural analgesia and anaesthesia; nevertheless, experience of their use in spinal anaesthesia is limited. The objective of this thesis was to evaluate their use in spinal anaesthesia for surgery in non-obstetric patients. My hypothesis was that levobupivacaine and ropivacaine are effective local anaesthetic agents for spinal anaesthesia in lower limb and urological surgery. In order to test this hypothesis, I conducted five clinical studies on 269 patients who had urological surgery or lower limb surgery under spinal or combined spinal-epidural anaesthesia. First, I investigated the efficacy and clinical characteristics of levobupivacaine and the mixture of levobupivacaine with fentanyl in spinal anaesthesia. Next, I compared the use of ropivacaine-fentanyl with bupivacaine-fentanyl in spinal anaesthesia. Finally, I defined the dose-response relationship of ropivacaine in spinal anaesthesia using traditional dose-response methodology and defined the relative potency among levobupivacaine, ropivacaine and bupivacaine by comparing the defined ED50 in spinal anaesthesia using up-down sequential allocation method. / Lee, Ying Yin. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (M.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 133-150). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.