JUSTIFICATIVA E OBJETIVOS: O objetivo deste estudo foi comparar a unilateralidade do bloqueio subaracnoide obtido com ropivacaína hiperbárica e hipobárica. MÉTODOS: Estudo prospectivo aleatorizado conduzido em centro cirúrgico ortopédico. No total, 60 pacientes (ASA I-III) programados para cirurgia eletiva de artroplastia total do joelho foram incluídos no estudo. O grupo hipo (n = 30) recebeu 11,25 mg de ropivacaína (7,5 mg.mL-1) + 2 mL de água destilada (a densidade em temperatura ambiente foi 0,997) e o grupo hiper (n = 30) recebeu 11,25 mg de ropivacaína + 2 mL (5 mg.mL-1) de dextrose (a densidade em temperatura ambiente foi 1,015). Os pacientes no grupo hiperbárica foram posicionados com o lado operado para baixo e na posição de Fowler a 15º e os pacientes do grupo hipobárica foram posicionados com o lado operado para cima e na posição de Trendelenburg a 15º. O bloqueio combinado de raquianestesia e anestesia peridural (ACRP) foi realizado na linha mediana do interespaço lombar em L3 e L4. Foram avaliados os parâmetros hemodinâmicos e de bloqueio da coluna vertebral, tempo de regressão, sucesso da raquianestesia unilateral, conforto do paciente, do cirurgião e da cirurgia, tempo até a primeira requisição analgésica e efeitos adversos. RESULTADOS: O tempo necessário para atingir o nível de dermátomo T10 no lado operado foi menor no grupo hiper (612,00 ± 163,29 segundos) comparado ao grupo hipo (763,63 ± 208,35 segundos) (p < 0,05). O tempo para a regressão de dois segmentos do nível de bloqueio sensorial nos lados operado e não operado foi menor no grupo hipo do que no grupo hiper. CONCLUSÃO: A ropivacaína tanto hiperbárica quanto hipobárica (11,25 mg) proporcionou anestesia adequada e confiável para artroplastia total do joelho (ATJ), com um alto nível de conforto para o paciente e cirurgião. As soluções anestésicas hipobáricas locais fornecem um alto nível de anestesia unilateral, com rápida recuperação dos bloqueios sensitivo e motor e, portanto, pode ser preferível em regime ambulatorial.

BACKGROUND AND OBJECTIVES: The aim of this study was to compare the unilaterality of subarachnoid block achieved with hyperbaric and hypobaric ropivacaine. METHODS: The prospective, randomized trial was conducted in an orthopedics surgical suite. In all, 60 ASA I-III patients scheduled for elective total knee arthroplasty were included in the study. Group Hypo (n = 30) received 11.25 mg of ropivacaine (7.5 mg.mL-1) + 2 mL of distilled water (density at room temperature was 0.997) and group Hyper (n = 30) received 11.25 mg of ropivacaine (7.5 mg.mL-1) + 2 mL (5 mg.mL-1) of dextrose (density at room temperature was 1,015). Patients in the hyperbaric group were positioned with the operated side down and in the 15º Fowler position, versus those in the hypobaric group with the operated side facing up and in the 15º Trendelenburg position. Combined spinal epidural anesthesia was performed midline at the L3-4 lumbar interspace. Hemodynamic and spinal block parameters, regression time, success of unilateral spinal anesthesia, patient comfort, surgical comfort, surgeon comfort, first analgesic requirement time, and adverse effects were assessed. RESULTS: Time to reach the T10 dermatome level on the operated side was shorter in group Hyper (612.00 ± 163.29 s) than in group Hypo (763.63 ± 208.35 s) (p < 0.05). Time to 2-segment regression of the sensory block level on both the operated and non-operated sides was shorter in group Hypo than in group Hyper. CONCLUSION: Both hyperbaric and hypobaric ropivacaine (11.25 mg) provided adequate and dependable anesthesia for total knee replacement surgery, with a high level of patient and surgeon comfort. Hypobaric local anesthetic solutions provide a high level of unilateral anesthesia, with rapid recovery of both sensory and motor block, and therefore may be preferable in outpatient settings.

JUSTIFICATIVA Y OBJETIVOS: El objetivo de este estudio fue comparar la unilateralidad del bloqueo subaracnoideo logrado con la ropivacaína hiperbárica y con la ropivacaína hipobárica. MÉTODOS: El estudio randomizado y prospectivo fue llevado a cabo en una sala quirúrgica ortopédica. En total, 60 pacientes ASA I-III seleccionados para artoplastia electiva total de rodilla fueron incluidos en el estudio. El grupo Hipo (n = 30) recibió 11,25 mg de ropivacaína (7.5 mg.mL-1) + 2 mL de agua destilada (la densidad en la temperatura ambiente era de 0,997) y el grupo Hiper (n = 30) recibió 11,25 mg de ropivacaína + 2 mL (5 mg.mL-1) de dextrosa (la densidad en la temperatura ambiente era de 1,015). Los pacientes del grupo hiperbárica fueron colocados con el lado operado hacia abajo y en la posición de Fowler a 15º, y los pacientes del grupo hipobárica fueron colocados con el lado operado hacia arriba en la posición de Trendelenburg a 15º. El bloqueo combinado de raquianestesia y de anestesia epidural (CRP) fue realizado en la línea media del interespacio lumbar en L3 y L4. Se evaluaron los parámetros hemodinámico y de bloqueo de la columna vertebral, el tiempo de regresión, el éxito de la raquianestesia unilateral, la comodidad del paciente, la tranquilidad en la cirugía y la comodidad del cirujano, así como el tiempo requerido para la primera analgesia y los efectos adversos. RESULTADOS: El tiempo necesario para alcanzar el nivel del dermatoma T10 en el lado operado fue más corto en el grupo Hiper (612,00 ± 163,29 segundos) que en el grupo Hipo (763,63 ± 208,35 segundos) (p < 0,05). El tiempo para la regresión de los dos segmentos del nivel de bloqueo sensorial tanto en el lado operado como en el no operado, fue más corto en el grupo Hipo que en el grupo Hiper. CONCLUSIONES: Tanto la ropivacaína hiperbárica como la hipobárica (11,25 mg) han demostrado una anestesia adecuada y confiable para la artoplastia total de rodilla (ATR), con un alto nivel de comodidad tanto para el paciente como para el cirujano. Las soluciones anestésicas hipobáricas locales suministran un alto nivel de anestesia unilateral con una rápida recuperación de los bloqueos sensorial y motor, y por tanto, puede ser preferible en un régimen ambulatorial.

OBJECTIVE: The goal of the study was to investigate the regional intravenous anesthesia procedure in knee arthroscopy and to evaluate the effects of adding ketamine over the anesthesia block charactery and tourniquet pain. MATERIAL/METHOD: Forty American Society of Anesthesiologists (ASA) II patients who received knee arthroscopy were enrolled. After monitoring, a peripheral IV line was inserted.The venous blood in the lower extremity was evacuated with a bandage, and the proximal cuff of the double-cuff tourniquet was inflated. The patients were randomly split into two groups. While Group P received 80 ml 0.5% prilocaine, Group PK received 0.15 mg/kg ketamine (80 ml in total) via the dorsum of the foot. We recorded onset time of the sensory block, end time of the sensory block, presence of the motor block, the time when the patient verbally reported tourniquet pain and surgical pain, duration of tourniquet tolerance, fentanyl consumption during the operation, time to first analgesic requirement, methemoglobin values at 60 minutes, operative conditions, 24-hour analgesic consumption, discharge time, and hemodynamic parameters. RESULTS: The body mass index (BMI) of the patients who required general anesthesia was significantly higher than the BMI of other patients. The onset time of the sensory block was shorter for those in Group PK, but the time to first analgesic requirement was longer. CONCLUSION: Regional intravenous anesthesia using the doses and volumes commonly used in knee arthroscopy may be an inadequate block among patients with high BMI values. Moreover, the addition of ketamine to the local anesthetic solution may produce a partial solution by shortening the onset of sensory block and prolonging the time until the first analgesic is required.

OBJECTIVES: The efficacy of combined lumbar plexus-sciatic nerve blocks was compared to epidural anesthesia in patients undergoing total knee surgery. PATIENTS AND METHODS: The study included 80 American Society of Anesthesiologists (ASA) Physical Status I-III patients (age range 18 to 65) undergoing knee surgery. The patients were randomly divided into one of two groups. Epidural anesthesia was performed in the epidural anesthesia (EA) group (n=40), and the lumbar plexus and sciatic nerves were blockedin the lumbar plexus-sciatic nerve blocks (LPSB) group (n=40). For each patient, onset of sensory and motor block, degree of motor block, sign of sensory block in the contralateral lower limb for the lumbar plexus-sciatic nerve blocks group, success in providing adequate anesthesia, hemodynamic changes, time of first analgesic request, and patient and surgeon satisfaction with the anesthetic technique were recorded. RESULTS: One patient in the epidural anesthesia group and three patients in the lumbar plexus-sciatic nerve blocks group required general anesthesia due to failed block. There were no significant differences between the two groups regarding the success of providing adequate anesthesia. Eight patients in the lumbar plexus-sciatic nerve blocks group developed contralateral spread. The onset of sensory-motor block and the time of the first analgesic request were significantly later in the lumbar plexus-sciatic nerve blocks group than in the epidural anesthesia group. Although there were no significant differences regarding patient satisfaction with the anesthetic technique between the two groups, surgeon satisfaction was significantly higher in the lumbar plexus-sciatic nerve blocks group than in the epidural anesthesia group. CONCLUSION: The lumbar plexus -sciatic nerve blocks provide effective unilateral anesthesia and may offer a beneficial alternative to epidural anesthesia in patients undergoing total knee surgery.