Comparison of the Effects of Four Subdoses of Dextroketamine to Reduce Pain during Posterior Brachial Plexus Block: A Randomized Double Blind Study.

BACKGROUND: The needle puncture produces discomfort during regional anesthesia. Sedation and local anesthesia are used to promote analgesia and amnesia. The main objective of this study was to compare the efficacy of four subanesthetic doses of dextroketamine for pain relief during brachial plexus block via the posterior approach. MATERIALS AND METHODS: Patients American Society of Anesthesiology I and II programed for elective surgery under brachial plexus block were distributed at randomized into four groups of twenty patients. Group A received dextroketamine 0.1 mg/kg, Group B received dextroketamine 0.15 mg/kg, Group C received dextroketamine 0.2 mg/kg, and Group D received dextroketamine 0.25 mg/kg. Sedation, facility to positioning, reaction to pinprick, nystagmus, hallucination, tachycardia, elevation of systolic blood pressure or cardiac rate, reduction in SpO2 (<96%), apnea, airway obstruction, collateral effects, and patient satisfaction were monitored. RESULTS: There is a positive correlation between increasing dose of ketamine and the degree of sedation and easiness to position the patient on the table. There exists a negative correlation associated between increasing the dose of ketamine and the response to pinprick, as also to the incidence of hallucination. CONCLUSION: Dextroketamine in doses of 0.1 mg/kg provide sufficient sedation to maintain the patient in position for brachial plexus block and for the relief of pain in 55% of them during the procedure, without hemodynamic variation. The pain relief and collateral effects are dose-dependent.

A comparison of thoracic spinal anesthesia with low-dose isobaric and low-dose hyperbaric bupivacaine for orthopedic surgery: A randomized controlled trial.

BACKGROUND: The thoracic spinal anesthesia was first described in 1909 and recently revised for various surgical procedures. This is a prospective study aims to evaluate the parameters of the thoracic spinal anesthesia (latency, motor block and paresthesia), the incidence of cardiovascular changes and complications comparing low doses of isobaric and hyperbaric bupivacaine. MATERIALS AND METHODS: A total of 200 orthopedic patients operated under spinal anesthesia were included in this study. Spinal anesthesia was between T9-T10, with a 27G cutting point or pencil tip in lateral or sitting. Spinal anesthesia was performed with 0.5% bupivacaine isobaric or hyperbaric. Patients remained in cephalad or head down position 10-20° for 10 minutes. We evaluated the demographics, analgesia, and degree of motor block, incidence of paresthesia, bradycardia, hypotension, anesthesia success and neurological complications. RESULTS: All patients developed spinal and there was no failure. The solution did not affect the onset of the blockade. The duration of motor block was greater than the sensitive with isobaric. The duration of sensory block was greater than the motor block with hyperbaric solution. The incidence of paresthesia was 4%, with no difference between the needles. The incidence of hypotension was 12.5% with no difference between the solutions. There was no neurological damage in all patients. CONCLUSION: The beginning of the block is fast regardless of the solution used. By providing a sensory block of longer duration than the motor block hyperbaric bupivacaine is reflected in a better indication. Thoracic spinal anesthesia provides excellent anesthesia for lower limb orthopedic surgery.

A new, lateral, continuous, combined, femoral-sciatic nerve approach via a single skin puncture for postoperative analgesia in intramedullary tibial nail insertion.

BACKGROUND: The prevalence of anterior knee pain following intramedullary tibial nail insertion is high. Continuous peripheral nerve blockade is an alternative method of pain control to opiods. This case illustrates the use of femoral nerve and sciatic nerve peripheral catheters with an elastomeric infusion pump for major intramedullary nailing surgery. CASE REPORT: A 36-year-old male with fractures to the left leg bones presented for placement of an intramedullary nail under spinal anesthesia. At the end of the procedure, access to the lateral femoral and sciatic continuous nerve block was achieved by using a stimulator connected to a 110 mm 18G Tuohy needle. Postoperative analgesia was provided with a 40-hour infusion of 0.1% bupivacaine (400 mL) at a rate of 10 mL hour(-1) with an elastomeric pump. Anesthetic dispersion and contrast were investigated. The analog scale remained with scores below 3 during the 40 hours after surgery, and boluses were not necessary. CONCLUSION: The use of a femoral and sciatic nerve peripheral catheter offered an alternative to conventional pain control. Continuous femoral-sciatic peripheral blockade via a skin puncture with an infusion of 0.1% bupivacaine with elastomeric pumps is a safe and effective procedure in adults.

Diminuição da concentração da levobupivacaína em excesso enantiomérico (S75: R25) para 0, 4% hiperbárica proporciona raquianestesia unilateral: estudo com diferentes volumes / Reducing the concentration to 0. 4% enantiomeric excess hyperbaric levobupivacaine (S75: R25) provides unilateral spinal anesthesia: study with different volumes / Disminución de la concentración de la levobupivacaína en exceso enantiomérico (S75: R25) para 0, 4% hiperbárica que proporciona raquianestesia unilateral: estudio con diferentes volúmenes

JUSTIFICATIVA E OBJETIVOS: Raquianestesia unilateral pode-se obter com solução hipobárica ou hiperbárica. O objetivo deste estudo foi comparar diferentes doses de levobupivacaína em excesso enantiomérico hiperbárico para se obter raquianestesia unilateral. PACIENTES E MÉTODO: Cento e vinte pacientes foram aleatoriamente separados para receber 4 mg, 6 mg ou 8 mg de levobupivacaína em excesso enantiomérico a 0,4%. As soluções foram administradas entre L3-L4, em posição lateral e permanecendo nessa posição em 5, 10 ou 15 minutos de acordo com a dose empregada. Bloqueios sensitivo (picada de agulha) e motor (escala de 0 a 3) foram comparados entre o lado a ser operado e contralateral. RESULTADOS: O início da analgesia foi rápido e comparável entre os grupos. Em todos os momentos das avaliações o bloqueio sensitivo no membro operado foi significativamente mais alto do que no membro não operado. O aumento de 1 mL (2 mg) na dose correspondeu a um aumento de dois segmentos (moda) no lado operado. No lado operado, o bloqueio motor completo (BM = 3) ocorreu em 31 (77,5%) dos pacientes com 4 mg, 38 (95%) com 6 mg e 40 (100%) com 8 mg. Houve uma correlação positiva entre o aumento da dose, a duração do bloqueio e a hipotensão. Todos os pacientes tiveram uma satisfação ótima com a técnica usada. CONCLUSÕES: A raquianestesia com diferentes volumes da solução de levobupivacaína em excesso enantiomérico (S75:R25) hiperbárica proporcionou uma incidência de 78% de unilateralidade do bloqueio espinal, sendo a menor dose empregada (4 mg) a mais eficiente.

BACKGROUND AND OBJECTIVES: Unilateral spinal anesthesia may be obtained with hypobaric or hyperbaric solution. The objective of this study was to compare different doses of enantiomeric excess hyperbaric levobupivacaine to achieve unilateral spinal anesthesia. METHOD: One hundred and twenty patients were randomized to receive 4 mg, 6 mg or 8 mg of 0.4% enantiomeric excess levobupivacaine. The solutions were administered at the L3-L4, with the patient in a lateral position and kept at this position according to dose administration for 5, 10 or 15 minutes. Sensory block (pinprick) and motor block (scale 0-3) were compared between the operated and contralateral sides. RESULTS: The onset of analgesia was rapid and comparable between groups. Sensory block was significantly higher in the operated than in nonoperated limb at all times of evaluation. Increasing the dose by 1 mL (2 mg) corresponded to an increase of two segments in the mode for the operated side. In the operated side, motor block (MB = 3) of patients occurred in 31 (77.5%) with 4mg, 38 (95%) with 6 mg, and 40 (100%) with 8 mg. There was a positive correlation between increased dose, blockade duration, and hypotension. All patients were satisfied with the technique used. CONCLUSIONS: Spinal anesthesia with different volumes of enantiomeric excess hyperbaric bupivacaine (S75: R25) provided a 78% incidence of unilateral spinal block, with the smallest dose used (4 mg) the most efficient.

JUSTIFICATIVA Y OBJETIVOS: La Raquianestesia unilateral se puede obtener con una solución hipobárica o hiperbárica. El objetivo de este estudio, fue comparar las diferentes dosis de levobupivacaína en exceso enantiomérico hiperbárico para poder obtener la raquianestesia unilateral. PACIENTES Y MÉTODO: Ciento veinte pacientes fueron aleatoriamente separados para recibir 4 mg, 6 mg u 8 mg de levobupivacaína en exceso enantiomérico al 0,4%. Las soluciones fueron administradas entre L3-L4, en posición lateral permaneciendo en esa posición en 5, 10 ó 15 minutos de acuerdo con la dosis usada. Los bloqueos sensitivo (picada de aguja) y motor (escala de 0 a 3) se compararon entre el lado que sería operado y el lado contralateral. RESULTADOS: El inicio de la analgesia fue rápido y se comparó entre los grupos. En todos los momentos de las evaluaciones, el bloqueo sensitivo en el miembro operado fue significativamente más alto que en el miembro no operado. El aumento de 1 mL (2 mg) en la dosis correspondió a un aumento de los segmentos en la moda en el lado operado. En el lado operado, el bloqueo motor completo (BM = 3) se dio en 31 (77,5%) de los pacientes con 4 mg, 38 (95%) con 6 mg y 40 (100%) con 8 mg. Hubo una correlación positiva entre el aumento de la dosis, la duración del bloqueo y la hipotensión. Todos los pacientes alcanzaron una excelente satisfacción con la técnica usada. CONCLUSIONES: La raquianestesia con diferentes volúmenes de la solución de levobupivacaína en exceso enantiomérico (S75:R25) hiperbárica, proporcionó una incidencia de un 78% de unilateralidad del bloqueo espinal, siendo la menor dosis usada (4 mg) la más eficiente.

Reducing the concentration to 0.4% enantiomeric excess hyperbaric levobupivacaine (s75: r25) provides unilateral spinal anesthesia. Study with different volumes.

BACKGROUND AND OBJECTIVES: Unilateral spinal anesthesia may be obtained with hypobaric or hyperbaric solution. The objective of this study was to compare different doses of enantiomeric excess hyperbaric levobupivacaine to achieve unilateral spinal anesthesia. METHOD: One hundred and twenty patients were randomized to receive 4 mg, 6 mg or 8 mg of 0.4% enantiomeric excess levobupivacaine. The solutions were administered at the L3-L4, with the patient in a lateral position and kept at this position according to dose administration for 5, 10 or 15 minutes. Sensory block (pinprick) and motor block (scale 0-3) were compared between the operated and contralateral sides. RESULTS: The onset of analgesia was rapid and comparable between groups. Sensory block was significantly higher in the operated than in nonoperated limb at all times of evaluation. Increasing the dose by 1 mL (2mg) corresponded to an increase of two segments in the mode for the operated side. In the operated side, motor block (MB = 3) of patients occurred in 31 (77.5%) with 4 mg, 38 (95%) with 6 mg, and 40 (100%) with 8 mg. There was a positive correlation between increased dose, blockade duration, and hypotension. All patients were satisfied with the technique used. CONCLUSIONS: Spinal anesthesia with different volumes of enantiomeric excess hyperbaric bupivacaine (S75: R25) provided a 78% incidence of unilateral spinal block, with the smallest dose used (4 mg) the most efficient.

Hypobaric 0.15% bupivacaine versus hypobaric 0.6% lidocaine for posterior spinal anesthesia in outpatient anorectal surgery.

BACKGROUND AND OBJECTIVES: Low doses of bupivacaine and lidocaine have been used for spinal anesthesia in outpatient surgery. The objective of this study was to compare hypobaric solutions of bupivacaine and lidocaine in outpatient anorectal surgery. METHODS: One hundred and fifty patients, divided in two groups, physical status ASA I-II, scheduled for anorectal surgery in the jackknife position received 3 mL (4.5 mg) of hypobaric 0.15% bupivacaine or 3 mL (18 mg) of hypobaric 0.6% lidocaine. The selectivity of the blockade, quality of surgical anesthesia, intensity of the motor blockade, and time for patient recovery were compared. After patients were discharged, daily phone contact was maintained for three days and on the 30th postoperative day. RESULTS: Adequate surgical blockade was achieved in all patients. The mean level of cephalad dispersion was L(1), ranging from T(10)-L(3), with bupivacaine, and L(1), ranging from T(11)-L(2), with lidocaine. Motor blockade was not observed in 135 patients (65 in the bupivacaine group x 70 in the lidocaine group). None of the patients developed hypotension and bradycardia. The sensorial blockade had a mean duration of 99.1 (11.0) minutes, with bupivacaine, and 64.1 (7.6) minutes, with lidocaine (p < 0.0005). Post-lumbar puncture headache was not observed in any patient. CONCLUSIONS: Hypobaric solution of bupivacaine or lidocaine promotes, predominantly, sensorial blockade after subarachnoid injection in patients in the jackknife position. Hypobaric lidocaine provides analgesia with the same dispersion of that of bupivacaine, but with shorter duration. Hemodynamic stability and the absence of motor blockade represent the major advantages.

Bupivacaína 0, 15 por cento hipobárica versus lidocaína 0, 6 por cento hipobárica para raquianestesia posterior em cirurgia anorretal ambulatorial / Hypobaric 0. 15 percent bupivacaine versus hypobaric 0. 6 percent lidocaine for posterior spinal anesthesia in outpatient anorectal surgery / Bupivacaína 0, 15 por ciento hipobárica versus lidocaína 0, 6 por ciento hipobárica para raquianestesia posterior en cirugía anorrectal ambulatorial

JUSTIFICATIVA E OBJETIVOS: Baixas doses de bupivacaína e lidocaína têm sido usadas para raquianestesia em cirurgia ambulatorial. O objetivo deste estudo foi comparar a bupivacaína com a lidocaína ambas em solução hipobárica em pacientes ambulatoriais de cirurgia anorretal. MÉTODO: Dois grupos de 75 pacientes, estado físico ASA I-II, candidatos a cirurgia anorretal em posição de canivete, receberam 3 mL (4,5 mg) de bupivacaína 0,15 por cento hipobárica ou 3 mL (18 mg) de lidocaína 0,6 por cento hipobárica. Foram comparados a seletividade do bloqueio, a qualidade da analgesia cirúrgica, a intensidade do bloqueio motor e o tempo de recuperação no paciente de cirurgia ambulatorial. Após a alta foi mantida comunicação diária por telefone até o 3º dia e depois no 30º de pós-operatório. RESULTADOS: O bloqueio foi adequado para cirurgia em todos os pacientes. O nível médio da dispersão cefálica foi L1 com variação de T10-L3 com a bupivacaína e L1 com variação T11-L2 com a lidocaína. Não foi observado bloqueio motor em 135 pacientes (65 da bupivacaína x 70 da lidocaína). Hipotensão e bradicardia não foram observadas em nenhum paciente. A média de duração do bloqueio sensitivo foi de 99,1 (11,0) minutos com a bupivacaína e 64,1 (7,6) minutos com a lidocaína, com diferença significante (p < 0,0005). Cefaleia pós-punção lombar não ocorreu em nenhum paciente. CONCLUSÕES: Bupivacaína ou lidocaína em solução hipobárica promove predominantemente bloqueio sensitivo após injeção subaracnóidea na posição de canivete. A solução de lidocaína hipobárica proporciona analgesia com a mesma dispersão da bupivacaína, porém com menor duração. As maiores vantagens incluem estabilidade hemodinâmica e ausência de bloqueio motor.

BACKGROUND AND OBJECTIVES: Low doses of bupivacaine and lidocaine have been used for spinal anesthesia in outpatient surgery. The objective of this study was to compare hypobaric solutions of bupivacaine and lidocaine in outpatient anorectal surgery. METHODS: One hundred and fifty patients, divided in two groups, physical status ASA I-II, scheduled for anorectal surgery in the jackknife position received 3 mL (4.5 mg) of hypobaric 0.15 percent bupivacaine or 3 mL (18 mg) of hypobaric 0.6 percent lidocaine. The selectivity of the blockade, quality of surgical anesthesia, intensity of the motor blockade, and time for patient recovery were compared. After patients were discharged, daily phone contact was maintained for three days and on the 30th postoperative day. RESULTS: Adequate surgical blockade was achieved in all patients. The mean level of cephalad dispersion was L1, ranging from T10-L3, with bupivacaine, and L1, ranging from T11-L2, with lidocaine. Motor blockade was not observed in 135 patients (65 in the bupivacaine group x 70 in the lidocaine group). None of the patients developed hypotension and bradycardia. The sensorial blockade had a mean duration of 99.1 (11.0) minutes, with bupivacaine, and 64.1 (7.6) minutes, with lidocaine (p < 0.0005). Post-lumbar puncture headache was not observed in any patient. CONCLUSIONS: Hypobaric solution of bupivacaine or lidocaine promotes, predominantly, sensorial blockade after subarachnoid injection in patients in the jackknife position. Hypobaric lidocaine provides analgesia with the same dispersion of that of bupivacaine, but with shorter duration. Hemodynamic stability and the absence of motor blockade represent the major advantages.

JUSTIFICATIVA Y OBJETIVOS: Bajas dosis de bupivacaína y lidocaína han sido usadas para raquianestesia en cirugía ambulatorial. El objetivo de este estudio fue comparar la bupivacaína con la lidocaína ambas en solución hipobárica en pacientes ambulatoriales de cirugía anorrectal. MÉTODOS: Dos grupos de 75 pacientes, estado físico ASA I-II, candidatos a cirugía anorrectal en posición prona (prone jacknife), que recibieron 3 mL (4,5 mg) de bupivacaína 0,15 por ciento hipobárica o 3 mL (18 mg) de lidocaína 0,6 por ciento hipobárica. Fueron comparados la selectividad del bloqueo, la calidad de la analgesia quirúrgica, la intensidad del bloqueo motor y el tiempo de recuperación en el paciente de cirugía ambulatorial. Después del alta se mantuvo la comunicación diaria por teléfono hasta el 3º día y después en el 30º de postoperatorio. RESULTADOS: El bloqueo fue adecuado para la cirugía en todos los pacientes. El nivel promedio de la dispersión cefálica fue L1 con variación de T10-L3 con la bupivacaína y L1 con variación T11-L2 con la lidocaína. No se observó bloqueo motor en 135 pacientes (65 de la bupivacaína x 70 de la lidocaína). La hipotensión y la bradicardia no se detectaron en ningún paciente. El promedio de duración del bloqueo sensitivo fue de 99,1 (11,0) minutos con la bupivacaína y de 64,1 (7,6) minutos con la lidocaína, con una diferencia significativa (p < 0,0005). La cefalea post-punción lumbar no acaeció en ningún paciente. CONCLUSIONES: La Bupivacaína o la lidocaína en solución hipobárica generan predominantemente un bloqueo sensitivo después de la inyección subaracnoidea en la posición prona. La solución de lidocaína hipobárica proporciona una analgesia con la misma dispersión de la bupivacaína, pero con menor duración. Las mayores ventajas incluyen una estabilidad hemodinámica y la ausencia de bloqueo motor.

Assessment of the densities of local anesthetics and their combination with adjuvants: an experimental study.

BACKGROUND AND OBJECTIVES: The relative density of a local anesthetic in relation to that of the cerebrospinal fluid (CSF) at 37 degrees C is one of the most important physical properties that affect the level of analgesia obtained after the subarachnoid administration of the drug. The objective of this study was to determine the density of local anesthetic solutions, with and without glucose, and the combination of the local anesthetic with adjuvants at 20 degrees C, 25 degrees C, and 37 degrees C. METHODS: The density (g.mL(-1)) was determined by using a DMA 450 densimeter with a sensitivity of +/- 0.00001 g.mL(-1). The densities, and variations, according to the temperature were obtained for all local anesthetics and their combination with opioids at 20 degrees C, 25 degrees C, and 37 degrees C. The solution is hyperbaric if its density exceeds 1.00099, hypobaric when its density is lower than 1.00019, and isobaric when its density is greater than 1.00019 and lower than 1.00099. RESULTS: The densities of both local anesthetics and adjuvants decrease with the increase in temperature. At 37 degrees C, all glucose-containing solutions are hyperbaric. In the absence of glucose, all solutions are hypobaric. At 37 degrees C, morphine, fentanyl, sufentanil, and clonidine are hypobaric. CONCLUSIONS: The densities of local anesthetics and adjuvants decrease with the increase in temperature and increase when glucose is added. The knowledge of the relative density helps select the most adequate local anesthetic to be administered in the subarachnoid space.

Avaliação da Densidade dos anestésicos locais e da combinação com adjuvantes: estudo em laboratório / Assessment of the densities of local anesthetics and their combination with adjuvants: an experimental study / Evaluación de la densidad de los anestésicos locales y de la combinación con adyuvantes: estudio en laboratorio

JUSTIFICATIVA E OBJETIVOS: Uma das mais importantes propriedades físicas que afetam o nível da analgesia obtida após a injeção subaracnoidea de um anestésico local é sua densidade relativa à densidade do líquido cefalorraquidiano (LCR) a 37ºC. O objetivo deste trabalho foi determinar a densidade das soluções de anestésicos locais com e sem glicose e a combinação de anestésico local com adjuvantes a 20ºC, 25ºC e 37ºC em avaliação laboratorial. MÉTODO: A densidade (g.mL-1) foi medida como auxílio de um densímetro DMA 450, sensível a ± 0,00001 g.mL-1. A densidade e suas variações com a temperatura foram obtidas de todos os anestésicos locais e suas combinações com opioides a 20ºC, 25ºC e 37ºC. A solução é hiperbárica se sua densidade excede a 1,00099, a solução é hipobárica quando a densidade está abaixo de 1,00019 e é isobárica quando a densidade é maior que 1,00019 e menor que 1,00099. RESULTADOS: Ambos, anestésicos locais e adjuvantes, exibem diminuição da densidade quando se aumenta a temperatura. A 37ºC, todas as soluções que contêm glicose são hiperbáricas. Na ausência de glicose, todas as soluções são hipobáricas. A 37ºC, morfina, fentanil, sufentanil e clonidina são hipobáricas. CONCLUSÕES: A densidade dos anestésicos locais e adjuvantes diminui com o aumento da temperatura e aumenta com a adição de glicose. O conhecimento da baricidade, densidade relativa, ajuda na seleção do anestésico local mais adequado e dos adjuvantes para uso subaracnoideo.

BACKGROUND AND OBJECTIVES: The relative density of a local anesthetic in relation to that of the cerebrospinal fluid (CSF) at 37º C is one of the most important physical properties that affect the level of analgesia obtained after the subarachnoid administration of the drug. The objective of this study was to determine the density of local anesthetic solutions, with and without glucose, and the combination of the local anesthetic with adjuvants at 20º C, 25º C, and 37º C. METHODS: The density (g.mL-1) was determined by using a DMA 450 densimeter with a sensitivity of ± 0.00001 g.mL-1. The densities, and variations, according to the temperature were obtained for all local anesthetics and their combination with opioids at 20ºC, 25ºC, and 37ºC. The solution is hyperbaric if its density exceeds 1.00099, hypobaric when its density is lower than 1.00019, and isobaric when its density is greater than 1.00019 and lower than 1.00099. RESULTS: The densities of both local anesthetics and adjuvants decrease with the increase in temperature. At 37º C, all glucose-containing solutions are hyperbaric. In the absence of glucose, all solutions are hypobaric. At 37ºC, morphine, fentanyl, sufentanil, and clonidine are hypobaric. CONCLUSIONS: The densities of local anesthetics and adjuvants decrease with the increase in temperature and increase when glucose is added. The knowledge of the relative density helps select the most adequate local anesthetic to be administered in the subarachnoid space.

JUSTIFICATIVA Y OBJETIVOS: Una de las más importantes propiedades físicas que afectan el nivel de la analgesia obtenida después de la inyección subaracnoidea de un anestésico local, es su densidad relativa a la densidad del líquido cefalorraquídeo (LCR) a 37ºC. El objetivo de este trabajo fue determinar la densidad de las soluciones de anestésicos locales con y sin glucosa y la combinación de anestésico local con adyuvantes a 20ºC, 25ºC y 37ºC en evaluación laboratorial. MÉTODO: La densidad (g.mL-1) se midió con la ayuda de un densímetro DMA 450 sensible a ± 0.00001 g.mL-1. La densidad y sus variaciones con la temperatura se obtuvieron de todos los anestésicos locales y de sus combinaciones con opioides a 20ºC, 25ºC y 37ºC. La solución es hiperbárica si su densidad excede a 1.00099, la solución es hipobárica cuando la densidad está por debajo de 1,00019 y es isobárica cuando la densidad es mayor que 0,00019 y menor que 1,00099. RESULTADOS: Ambos anestésicos locales y los adyuvantes, arrojan una reducción de la densidad cuando se aumenta la temperatura. A 37ºC, todas las soluciones que contienen glucosa son hiperbáricas. Con la falta de glucosa, todas las soluciones son hipobáricas. A 37ºC, morfina, fentanil, sufentanil y clonidina son hipobáricas. CONCLUSIONES: La densidad de los anestésicos locales y adyuvantes se reduce con el aumento de la temperatura y aumenta con la adición de glucosa. El conocimiento de la baricidad, densidad relativa, ayuda a la selección del anestésico local más adecuado y de los adyuvantes para uso subaracnoideo.

Pudendal block with bupivacaine for postoperative pain relief.

PURPOSE: Postoperative pain after hemorrhoidectomy is very intense, and the pain at the first postoperative defecation is very intense. Based on our pilot initial results that reflected reduced postoperative pain, we conducted a prospective, randomized, double-blind study to investigate whether the analgesia produced by bilateral pudendal nerve block using a nerve-stimulator could provide better postoperative pain relief compared with the routine technique in use in the Department of Anesthesia. METHODS: After Ethical Committee approval and informed consent, 100 patients scheduled for hemorrhoidectomy were randomized into control (C) and study (P) groups with 50 patients each. Bilateral pudendal nerve block with 0.25 percent bupivacaine was performed with nerve-stimulator. Evaluated parameters were pain severity, duration of analgesia, demand analgesia, and possible technique-related complications. Data were evaluated 6, 12, 18, and 24 hours after surgery completion. The first defecation and patient satisfaction were recorded. RESULTS: Successful pudendal nerves stimulation was achieved in all patients in the study group. The pudendal nerve block group was found to have better postoperative pain relief, reduced need for analgesics, and patient satisfaction. Mean analgesic duration was 23.8 +/- 4.8 hours vs. 3.6 +/- 1 hours. All patients in the pudendal nerve block had spontaneous micturition vs. 48 patients in the control group. The pudendal analgesia was considered excellent by 44 patients and satisfactory by 6 male patients. The six male patients complained because of penile anesthesia. No anesthetic-related local or systemic complications were observed. CONCLUSIONS: In this controlled study, bilateral pudendal nerve block oriented by nerve stimulator provided excellent analgesia with low need for opioids, without local or systemic complications, and without urinary retention.

Baixa dose de bupivacaína isobárica, hiperbárica ou hipobárica para raquianestesia unilateral / Low dose isobaric, hyperbaric, or hypobaric bupivacaine for unilateral spinal anesthesia

JUSTIFICATIVA E OBJETIVOS: A raquianestesia unilateral pode apresentar vantagens principalmente em pacientes em regime ambulatorial. Baixa dose da solução anestésica, velocidade lenta da injeção espinal e a posição lateral facilitam a obtenção da distribuição unilateral na raquianestesia. Foram comparadas soluções isobárica, hiperbárica e hipobárica de bupivacaína com objetivos de se obter raquianestesia unilateral em pacientes submetidos a intervenções cirúrgicas ortopédicas em regime ambulatorial. MÉTODO: Cento e cinqüenta pacientes foram aleatoriamente separados em três grupos para receberem 5 mg de bupivacaína a 0,5 por cento isobárica (Grupo Iso), ou 5 mg de bupivacaína a 0,5 por cento hiperbárica (Grupo Hiper), ou 5 mg de bupivacaína a 0,15 por cento hipobárica (Grupo Hipo). As soluções foram administradas no interespaço L3-L4 com o paciente na posição lateral e permanecendo nesta posição por 20 minutos. A anestesia sensitiva foi avaliada pelo teste da picada da agulha. O bloqueio motor avaliado pela escala modificada de Bromage. Ambos os bloqueios foram comparados com o lado não operado e entre si. RESULTADOS: Existiu diferença significativa entre o lado operado e não-operado em todos os três grupos aos 20 minutos, mas maior freqüência de raquianestesia unilateral foi obtida com as soluções hiperbárica e hipobárica de bupivacaína. Bloqueio sensitivo e motor foram observados em 14 pacientes do Grupo Iso, 38 pacientes no Grupo Hiper e 40 pacientes no Grupo Hipo. Não ocorreram alterações hemodinâmicas em nenhum paciente. Não foram observados cefaléia pós-punção nem sintomas neurológicos temporários. CONCLUSÕES: A raquianestesia com soluções hipobárica e hiperbárica proporcionou maior freqüência de unilateralidade. Após 20 minutos a solução isobárica de bupivacaína mobilizou-se no líquido cefalorraquidano (LCR), resultando em apenas 28 por cento de raquianestesia unilateral.

BACKGROUND AND OBJECTIVES: Unilateral spinal anesthesia has its advantages, especially in patients undergoing outpatient basis surgeries. Low dose, slow speed of administration, and the lateral positioning make easier the unilateral distribution in spinal anesthesia. Isobaric, hyperbaric, and hypobaric solutions of bupivacaine were compared in the unilateral spinal anesthesia in patients undergoing outpatient basis orthopedic surgeries. METHODS: One hundred and fifty patients were randomly divided in three groups to receive 5 mg of 0.5 percent isobaric bupivacaine (Iso Group), 5 mg of 0.5 percent hyperbaric bupivacaine (Hyper Group), or 5 mg of 0.15 percent hypobaric bupivacaine (Hypo Group). The solutions were administered in the L3-L4 space with the patient in the lateral decubitus and remaining in this position for 20 minutes. Sensitive anesthesia was evaluated by the pin prick test. Motor blockade was determined by the modified Bromage scale. Both blockades were compared with the opposite side and among themselves. RESULTS: There was a significant difference between the side of the surgery and the opposite side in all three groups at 20 minutes, but the frequency of unilateral spinal anesthesia was greater with the hyperbaric and hypobaric solutions. Sensitive and motor blockades were observed in 14 patients in the Iso Group, 38 patients in the Hyper Group, and 40 patients in the Hypo Group. Patients did not develop any hemodynamic changes. Postpuncture headache and transitory neurological symptoms were not observed. CONCLUSIONS: Spinal anesthesia with hypobaric and hyperbaric solutions present a higher frequency of unilateral anesthesia. After 20 minutes, isobaric bupivacaine mobilized into cerebrospinal fluid (CSF) resulted in unilateral spinal anesthesia in only 28 percent of the patients.

JUSTIFICATIVA Y OBJETIVOS: La anestesia raquidea unilateral puede presentar ventajas principalmente en pacientes en régimen ambulatorial. Baja dosis de la solución anestésica, velocidad lenta de la inyección espinal y la posición lateral facilitan la obtención de la distribución unilateral en la anestesia raquidea. Se compararon las soluciones isobara, hiperbara e hipobara de bupivacaína para obtener la anestesia raquidea unilateral en pacientes sometidos a intervenciones quirúrgicas ortopédicas en régimen ambulatorial. MÉTODO: Ciento cincuenta pacientes fueron aleatoriamente separados en tres grupos para recibir 5 mg de bupivacaína a 0,5 por ciento isobara (Grupo Iso) o 5 mg de bupivacaína a 0,5 por ciento hiperbara (Grupo Hiper) o 5 mg de bupivacaína a 0,15 por ciento hipobara (Grupo Hipo). Las soluciones se administraron en el interespacio L3-L4 con el paciente en la posición lateral y permaneciendo en esa posición por 20 minutos. La anestesia sensitiva se evaluó por el test de la picada de la aguja. El bloqueo motor evaluado por la escala modificada de Bromage. Los dos bloqueos se compararon con el lado no operado y también entre sí. RESULTADOS: Se notó una diferencia significativa entre el lado operado y no operado en todos los tres grupos a los 20 minutos, pero se obtuvo una mayor frecuencia de anestesia raquidea unilateral con las soluciones hiperbara e hipobara de bupivacaína. Se observó bloqueo sensitivo y motor en 14 pacientes del Grupo Iso, 38 pacientes en el Grupo Hiper y 40 pacientes en el Grupo Hipo. No ocurrieron alteraciones hemodinámicas en ningún paciente. No se observó cefalea postpunción ni síntomas neurológicos transitorios. CONCLUSIONES: La anestesia raquidea con soluciones hipobara e hiperbara proporcionaron una mayor frecuencia de unilateralidad. Tras 20 minutos la solución isobara de bupivacaína se movió en el LCR resultando en apenas 28 por ciento de anestesia raquidea unilateral.

[Low dose isobaric, hyperbaric, or hypobaric bupivacaine for unilateral spinal anesthesia.]. / Baixa dose de bupivacaína isobárica, hiperbárica ou hipobárica para raquianestesia unilateral.

BACKGROUND AND OBJECTIVES: Unilateral spinal anesthesia has its advantages, especially in patients undergoing outpatient basis surgeries. Low dose, slow speed of administration, and the lateral positioning make easier the unilateral distribution in spinal anesthesia. Isobaric, hyperbaric, and hypobaric solutions of bupivacaine were compared in the unilateral spinal anesthesia in patients undergoing outpatient basis orthopedic surgeries. METHODS: One hundred and fifty patients were randomly divided in three groups to receive 5 mg of 0.5% isobaric bupivacaine (Iso Group), 5 mg of 0.5% hyperbaric bupivacaine (Hyper Group), or 5 mg of 0.15% hypobaric bupivacaine (Hypo Group). The solutions were administered in the L3-L4 space with the patient in the lateral decubitus and remaining in this position for 20 minutes. Sensitive anesthesia was evaluated by the pin prick test. Motor blockade was determined by the modified Bromage scale. Both blockades were compared with the opposite side and among themselves. RESULTS: There was a significant difference between the side of the surgery and the opposite side in all three groups at 20 minutes, but the frequency of unilateral spinal anesthesia was greater with the hyperbaric and hypobaric solutions. Sensitive and motor blockades were observed in 14 patients in the Iso Group, 38 patients in the Hyper Group, and 40 patients in the Hypo Group. Patients did not develop any hemodynamic changes. Postpuncture headache and transitory neurological symptoms were not observed. CONCLUSIONS: Spinal anesthesia with hypobaric and hyperbaric solutions present a higher frequency of unilateral anesthesia. After 20 minutes, isobaric bupivacaine mobilized into cerebrospinal fluid (CSF) resulted in unilateral spinal anesthesia in only 28% of the patients.