[Translated article] In vitro elution of local anaesthetics from PMMA bone cement.

BACKGROUND AND AIM: Currently, we do not have a gold standard for pain management after total knee arthroplasty. We may use one of more drug delivery systems, none of which are ideal. An ideal depot delivery system would provide therapeutic, nontoxic, doses of drug at the surgical side, especially during 72h postoperatively. The bone cement used in arthroplasties has been used as a drug delivery system, especially antibiotics, since 1970. Based on this principle, we developed this study with the aim to characterize the elution profile of two local anaesthetics (lidocaine hydrochloride and bupivacaine hydrochloride) from PMMA (polymethilmethacrylate) bone cement. MATERIAL AND METHODS: Palacos® R+G bone cement and lidocaine hydrochloride or bupivacaine hydrochloride specimens were obtained depending on the study group. These specimens were immersed in PBS (phosphate buffered saline) and removed from the solution at different set times. Subsequently, the concentration of local anaesthetic in the liquid was analyzed by liquid chromatography. RESULTS: The percentage of lidocaine eluted from PMMA bone cement in this study was 9.74% of the total lidocaine content per specimen at 72h and 18.73% at 336h (14 days). In case of bupivacaine, the elution percentage was 2.71% of the total bupivacaine content per specimen at 72h and 2.70% at 336h (14 days). CONCLUSIONS: Local anaesthetics elute in vitro from PMMA bone cement, reaching doses at 72h close to the doses used in anaesthetic blocks.

[Translated article] In vitro elution of local anaesthetics from PMMA bone cement.

BACKGROUND AND AIM: Currently, we do not have a gold standard for pain management after total knee arthroplasty. We may use one of more drug delivery systems, none of which are ideal. An ideal depot delivery system would provide therapeutic, nontoxic, doses of drug at the surgical side, especially during 72h postoperatively. The bone cement used in arthroplasties has been used as a drug delivery system, especially antibiotics, since 1970. Based on this principle, we developed this study with the aim to characterise the elution profile of two local anaesthetics (lidocaine hydrochloride and bupivacaine hydrochloride) from PMMA (polymethilmethacrylate) bone cement. MATERIAL AND METHODS: Palacos® R+G bone cement and lidocaine hydrochloride or bupivacaine hydrochloride specimens were obtained depending on the study group. These specimens were immersed in PBS (phosphate buffered saline) and removed from the solution at different set times. Subsequently, the concentration of local anaesthetic in the liquid was analysed by liquid chromatography. RESULTS: The percentage of lidocaine eluted from PMMA bone cement in this study was 9.74% of the total lidocaine content per specimen at 72h and 18.73% at 336h (14 days). In case of bupivacaine, the elution percentage was 2.71% of the total bupivacaine content per specimen at 72h and 2.70% at 336h (14 days). CONCLUSIONS: Local anaesthetics elute in vitro from PMMA bone cement, reaching doses at 72h close to the doses used in anaesthetic blocks.

In vitro elution of local anesthetics from PMMA bone cement. / Estudio in vitro de elución de anestésicos locales en cemento óseo de PMMA.

BACKGROUND AND AIM: Currently, we do not have a gold standard for pain management after total knee arthroplasty. We may use one of more drug delivery systems, none of which are ideal. An ideal depot delivery system would provide therapeutic, nontoxic, doses of drug at the surgical side, especially during 72h postoperatively. The bone cement used in arthroplasties has been used as a drug delivery system, especially antibiotics, since 1970. Based on this principle, we developed this study with the aim to characterize the elution profile of two local anesthetics (lidocaine hydrochloride and bupivacaine hydrochloride) from PMMA (polymethilmethacrylate) bone cement. MATERIAL AND METHODS: Palacos® R+G bone cement and lidocaine hydrochloride or bupivacaine hydrochloride specimens were obtained depending on the study group. These specimens were immersed in PBS (phosphate buffered saline) and removed from the solution at different set times. Subsequently, the concentration of local anesthetic in the liquid was analyzed by liquid chromatography. RESULTS: The percentage of lidocaine eluted from PMMA bone cement in this study was 9.74% of the total lidocaine content per specimen at 72h and 18.73% at 336h (14 days). In case of bupivacaine, the elution percentage was 2.71% of the total bupivacaine content per specimen at 72h and 2.70% at 336h (14 days). CONCLUSIONS: Local anesthetics elute in vitro from PMMA bone cement, reaching doses at 72h close to the doses used in anesthetic blocks.

Analysis of bupivacaine and ropivacaine-related cardiac arrests in regional anesthesia: A systematic review of case reports.

Regional anesthesia as a component of multimodal analgesia protocols has become more and more a part of modern perioperative pain management. The widespread adoption of ultrasound guidance in regional anesthesia has surely played an important role in that growth and it has significantly improved patient safety, decreased the incidence of block failure, cardiac arrest, and reduced complication rates. The objective of this systematic review is to extract, analyze, and synthesize clinical information about bupivacaine and ropivacaine related cardiac arrest that we might have a clearer picture of the clinical presentation. The literature search identified 268 potentially relevant publications and 22 relevant case reports were included in the review. Patients' demographics, types of regional anesthesia, hypotension, heart rhythm disorders, seizures, cardiac arrest, fatal outcome, recommendations and limitations on prevention and treatment of bupivacaine and ropivacaine related cardiac arrest are analyzed and discussed in the systematic review. Both bupivacaine and ropivacaine-induced local anesthetic toxicity can result in cardiac arrest. Lipid emulsion, telemetry, local anesthetic toxicity resuscitation training appears to be promising in improvement of survival but more research is needed. Improvement and encouragement of reporting the local anesthetic toxicity are warranted to improve the quality of information that can be analyzed in order to make more precise conclusion.

Epidural anesthesia for cesarean section with 0.125% versus 0.25% bupivacaine: An Ecuadorian prospective cohort.

ANTECEDENTES: En una cesárea se puede emplear analgesia epidural con bupivacaína 0.125% and lidocaína 1.5% ó bupivacaína 0.25% and lidocaína 1.0%. Una concentración mayor de bupivacaína alcanza mayor analgesia con más eventos adversos. OBJETIVO: evaluar la analgesia y seguridad de bupivacaína 0.125% and lidocaína 1.5% ó bupivacaína 0.25% and lidocaína 1.0%. MATERIALES Y MÉTODOS: Cohorte prospectivo estratificado según ambas concentraciones de bupivacaína. RESULTADOS: Se recuperó cien gestantes a término (cincuenta por cohorte). A los 20 y 30 minutos tras la administración epidural hubo más casos con mayor bloqueo motor en quienes se empleó bupivacaína 0.125% and lidocaína 1.5% (p = 0.0229 y p = 0.0006, respectivamente). No hubo diferencia significativa respecto al bloqueo sensitivo. Bupivacaína 0.25% and lidocaína 1.5% mostró una tencencia a la hipotensión (p < 0.001) y a la bradicardia (p = 0.4100). De la cohorte de bupivacaína 0.125% and lidocaína 1.5%, 25 casos (50%) presentaron cuando menos un evento adverso, en contraste con 44/50 (88%) de la cohorte de bupivacaína 0.25% and lidocaína 1.0% (p < 0.001). CONCLUSIÓN: En la analgesia epidural durante cesárea, bupivacaína 0.125% and lidocaína 1.5% está asociado con un efecto analgésico similar a bupivacaína 0.25% and lidocaína 1.0%. Sin embargo, mayores concentraciones están significativamente relacionadas con mayor tasa de eventos adversos (especialmente hipotensión). BACKGROUND: In a cesarean section, epidural analgesia with 0.125% bupivacaine and 1.5% lidocaine or 0.25% bupivacaine with 1.0% lidocaine concentrations can be used. A higher concentration of bupivacaine reaches better analgesia but with a higher rate of drug-related adverse events. AIM: The aim of the study was to assess analgesia and safety of 0.125% bupivacaine and 1.5% lidocaine or 0.25% bupivacaine with 1.0% lidocaine during cesarean. MATERIALS AND METHODS: Prospective cohort stratified following both bupivacaine concentrations. RESULTS: One hundred women with full-term pregnancies were selected (fifty per cohort). At 20 and 30 min after epidural administration, there was a higher proportion of motor blockade cases from the 0.125% bupivacaine and 1.5% lidocaine cohort (p = 0.0229 and p = 0.0006, respectively). There was no significant difference among sensitive blockage. A 0.25% bupivacaine and 1.0% lidocaine concentration showed a tendency to hypotension (p < 0.001) and bradycardia (p = 0.4100). From 0.125% bupivacaine and 1.5% lidocaine cohort, 25 cases (50%) presented at least one adverse event; in contrast with 44/50 (88%) from 0.25% bupivacaine and 1.0% lidocaine cohort (p < 0.001). CONCLUSION: In epidural analgesia during cesarean, using 0.125% bupivacaine and 1.5% lidocaine presented similar analgesia than 0.25% bupivacaine and 1.0% lidocaine. However, a higher bupivacaine concentration is significantly related to more frequent drug-related adverse events (especially hypotension).

Spinal Myoclonus: Is It An Anesthetic Mystery? / Mioclonía espinal: ¿un misterio anestésico? ¡Se acepta el reto!

The goal is to present a descriptive study related an unprecedent case of spinal myoclonus (SM) following subarachnoid anesthesia (SA). SM are sudden, brief, involuntary non-generalized spasms that can be an adverse effect of drug administration via neuraxial routes. Female, 67y, ASA II, proposed for hip replacement surgery, with normal preoperative exams. 7min after SA with 10mg of bupivacaine 0,5%, no motor blockade observed, and patient complained of unbearable pain in legs and perineum and bilateral, asymmetrical and arrhythmic myoclonic movements in the lower limbs. The latter solved after 48h of general anesthesia and rocuronium perfusion, amongst other therapeutics. Accordingly, intrathecal bupivacaine appears to be the SM most likely cause, regarding the absence of neurologic and electrolyte disorders, spinal cord direct trauma, drug exchange and normal perioperative examination, imaging and laboratory testing.It is mandatory to always take the patients' anaesthetic histories and recognize, treat and report rare anaesthetic complications.

[Antimicrobial effects of fentanyl and bupivacaine]. / Efeitos antimicrobianos do fentanil e da bupivacaína: estudo in vitro.

STUDY OBJECTIVE: In this study, we aimed to compare the antimicrobial effects of bupivacaine and fentanyl citrate and to reveal the impact on antimicrobial effect potential in the case of combined use. DESIGN: In vitro prospective study. SETTING: University Clinical Microbiology Laboratory. MEASUREMENTS: In our study, in vitro antimicrobial effect of 0.05 mg.mL-1 fentanyl citrate, 5 mg.mL-1 bupivacaine were tested against Staphylococcus aureus American Type Culture Collection (ATCC) 29213, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 13883, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231 as Group F (Fentanyl Citrate) and Group B (Bupivacaine), respectively. S. aureus ATCC 29213, P. aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 13883 and Escherichia coli ATCC 25922 were cultured onto Mueller Hinton agar (Oxoid, UK) plates and Candida albicans ATCC 10231 were cultured onto Sabouraud dextrose agar (Oxoid, UK) plates for 18-24 hours at 37°C. MAIN RESULTS: In terms of inhibition zone diameters, S. Aureus ATCC 29213, P. aeruginosa ATCC 27853, and C. albicans ATCC10231 values obtained after 12 and 24 hours of incubation were significantly higher in Group F than Group B (p < 0.001). In terms of inhibition zone diameters, E. coli ATCC 25922, and K. pneumomiae ATCC 13883 values obtained after 12 and 24hours of incubation were significantly higher in Group B than Group F (p < 0.001, E. coli 12ª hour p = 0.005). CONCLUSIONS: Addition of fentanyl to Local Anesthetics (LAs) is often preferred in regional anesthesia applications in today's practice owing especially to its effect on decreasing the local anesthetic dose and increasing analgesia quality and patient satisfaction. However, when the fact that fentanyl antagonized the antimicrobial effects of LAs in the studies is taken into account, it might be though that it contributes to an increase in infection complications. When the fact that fentanyl citrate, which was used in our study and included hydrochloric acid and sodium hydroxide as protective agents, broadened the antimicrobial effect spectrum of LAs, had no antagonistic effect and showed a synergistic antimicrobial effect against E. Coli is considered, we are of the opinion that the addition of fentanyl to LAs would contribute significantly in preventing the increasing regional anesthesia infection complications.

[Influence of different local anesthetics on atracurium neuromuscular blockade on rats]. / Influência de diferentes anestésicos locais no bloqueio neuromuscular produzido pelo atracúrio em ratos.

INTRODUCTION: The association between Local Anesthetics (LAs) and Neuromuscular Blocking (NMB) drugs in clinical practice, and the possibility of interaction between these drugs has been investigated. LAs act on neuromuscular transmission in a dose-dependent manner and may potentiate the effects of NMB drugs. OBJECTIVE: The aim of this study was to evaluate, in an experimental model, the effect of lidocaine and racemic bupivacaine on neuromuscular transmission and the influence on neuromuscular blockade produced by atracurium. METHODS: Male Wistar rats, weighing from 250 g to 300g were used. The preparation was set up based on a technique proposed by Bülbring. Groups were formed (n = 5) according to the drug studied: lidocaine 20 µg.mL-1 (Group I); racemic bupivacaine 5 µg.mL-1 (Group II); atracurium 20 µg.mL-1 (Group III); atracurium 20 µg.mL-1 in a preparation previously exposed to lidocaine 20 µg.mL-1 and racemic bupivacaine 5 µg.mL-1, Groups IV and V, respectively. The following parameters were assessed: 1) Amplitude of hemi diaphragmatic response to indirect stimulation before and 60 minutes after addition of the drugs; 2) Membrane Potentials (MP) and Miniature Endplate Potentials (MEPPs). RESULTS: Lidocaine and racemic bupivacaine alone did not alter the amplitude of muscle response. With previous use of lidocaine and racemic bupivacaine, the neuromuscular blockade (%) induced by atracurium was 86.66 ± 12.48 and 100, respectively, with a significant difference (p = 0.003), in comparison to the blockade produced by atracurium alone (55.7 ± 11.22). These drugs did not alter membrane potential. Lidocaine initially increased the frequency of MEPPs, followed by blockade. With the use of bupivacaine, the blockade was progressive. CONCLUSIONS: Lidocaine and racemic bupivacaine had a presynaptic effect expressed by alterations in MEPPs, which may explain the interaction and potentiation of NMB produced by atracurium.

[Addition of dexmedetomidine to bupivacaine in ultrasonography-guided paravertebral blockade potentiates postoperative pain relief among patients undergoing thoracotomy]. / Adição de dexmedetomidina à bupivacaína em bloqueio paravertebral guiado por ultrassom potencializa o alívio da dor pós­operatória em pacientes submetidos à toracotomia.

BACKGROUND AND OBJECTIVE: Thoracic paravertebral blockade is an alternative regional technique for comforting post-thoracotomy pain, thereby decreasing opioid consumption, postoperative nausea and vomiting, dizziness, respiratory depression and health care costs. The objective of this study was to investigate the effects of bupivacaine and bupivacaine plus dexmedetomidine on postoperative pain score and analgesic consumption in thoracotomy patients who had undergone ultrasonography-guided paravertebral blockade. MATERIAL AND METHOD: 93 ASA I-II patients aged 18-65 years were included in the study and scheduled for thoracic surgery. Prior to anesthesia induction, the paravertebral blockade procedure was performed by an anesthetist with ultrasonography. Cases were randomly stratified into three groups. The paravertebral blockade procedure was performed with 20mL 0.5% bupivacaine injection in Group B (n=31) and 20mL 0.5% bupivacaine+1mL dexmedetomidine (100µg) injection in Group BD. Group C received postoperative i.v. morphine via patient-controlled analgesia without paravertebral blockade. Post-operative pain scores were recorded in the recovery room and post-operatively using a VAS. Hemodynamic parameters, adverse effects and morphine consumption were also recorded. RESULTS: No significant difference was determined between Group B and Group C regarding intra-operative adverse effects such as bradicardia and hypotension, while these adverse effects were significantly higher in Group BD (p=0.04). VAS scores with rest and upon movement were significantly lower in Group BD compared to Group C (p<0.001). Total morphine consumption was significantly lower in both Group B and Group BD in comparison with Group C (p<0.001). In Group BD, HR and MAP were lower, but this was not clinically significant (p<0.05). CONCLUSION: The addition of dexmedetomidine to bupivacaine lowers postoperative pain scores and morphine consumption in thoracotomy patients who receive ultrasonography guided paravertebral blockade.

[Comparison of fentanyl and dexmedetomidine as an adjuvant to bupivacaine for unilateral spinal anesthesia in lower limb surgery: a randomized trial]. / Comparação de fentanil e dexmedetomidina como adjuvante à bupivacaína para raquianestesia unilateral em cirurgia de membros inferiores: estudo randômico.

BACKGROUND AND OBJECTIVES: One of the disadvantages of unilateral spinal anesthesia is the short duration of post-operative analgesia, which can be addressed by adding adjuvants to local anesthetics. The aim of current study was to compare the effects of adding dexmedetomidine, fentanyl, or saline to bupivacaine on the properties of unilateral spinal anesthesia in patients undergoing calf surgery. METHODS: In this double-blind clinical trial, 90 patients who underwent elective calf surgery were randomly divided into three groups. The spinal anesthetic rate in each of the three groups was 1mL bupivacaine 0.5% (5mg). In groups BD, BF and BS, 5µg of dexmedetomidine, 25µg of fentanyl and 0.5mL saline were added, respectively. The duration of the motor and sensory blocks in both limbs and the rate of pain during 24h after surgery were calculated. Hemodynamic changes were also measured during anesthesia for up to 90min. RESULTS: The duration of both of motor and sensory block was significantly longer in dependent limb in the BF (96 and 169min) and BD (92 and 166min) groups than the BS (84 and 157min) group. Visual Analog Scale was significantly lower in the two groups of BF (1.4) and BD (1.3), within 24h after surgery, than the BS (1.6) group. CONCLUSIONS: The addition of fentanyl and dexmedetomidine to bupivacaine in unilateral spinal anesthesia can increase the duration of the motor and sensory block in dependent limb and prolong the duration of postoperative pain. However, fentanyl is more effective than dexmedetomidine.

Evaluation of temporal muscle trophism in relation to the manipulation time and infiltration of 0.5% isobaric bupivacaine through a pterional approach. / Evaluación del trofismo del músculo temporal posquirúrgico en relación con el tiempo de manipulación y la infiltración transoperatoria de bupivacaína isobárica al 0,5% en pacientes sometidos a craneotomía pterional.

INTRODUCTION: There are different techniques for the reconstruction of the temporal muscle (TM) in the pterional approach (PA) in order to avoid and reduce atrophy, it has not been able to avoid it in its entirety. The administration of bupivacaine generates regeneration of muscle fibres. There are no studies in the medical literature that evaluate the time of TM manipulation and the use of bupivacaine for the treatment of atrophy after pterional approach, the present investigation aim is to describe the effects of these variables. PATIENT AND METHODS: Longitudinal study, including patients from 18-80 years old with pterional approach at 2016-2017. We evaluated the effects of the TM manipulation times and the administration of 0.5% bupivacaine on the trophism and function of TM. RESULTS: Twenty-nine patients underwent a PA; 16(55.17%) count with criteria for 0.5% bupivacain infiltration. We found a negative correlation between manipulation times and trophism, with no statistically significance (p>.05). We evaluated presurgical and postsurgical index of Helkimo and Fonseca's index, finding an increase of disfunction with statistically significance (p<.05). In patients who were infiltrated with 0.5% bupivacaine we observed a mean difference in the TM's trophism of 0.275±1.18mm, in contrast with no infiltrated which was 2.39±1.30mm (t[27] = -5.118, p=.0001). CONCLUSIONS: The manipulation of the TM during a pterional approach conditioned an impact on the quality of life according to the disfunction indexes, due to atrophy. This investigation exhibits that de administration of 0.5% bupivacaine during surgery offers a decrease in the TM atrophy.

[Combination of clonidine-bupivacaine in caudal epidural anesthesia for hypospadias surgery in children: prospective, randomized, blind study]. / Associação clonidina­bupivacaína na anestesia peridural caudal para cirurgia de hipospádia em crianças: estudo prospectivo, randomizado, encoberto.

BACKGROUND AND OBJECTIVES: The combination of clonidine with local anesthetic administered for epidural anesthesia via caudal route seems to improve the quality of postoperative analgesia, but with conflicting results. This study compared the postoperative analgesia of three different doses of clonidine combined with bupivacaine in caudal epidural anesthesia in children undergoing hypospadias repair. METHODS: Eighty children aged 1 to 10 years, candidates for surgical repair of hypospadias, were randomly divided into four groups of 20 patients to receive general anesthesia combined with caudal epidural anesthesia with bupivacaine 0.165% alone or in combination with 1, 2 or 3µg.kg-1 of clonidine. The primary outcome was morphine consumption in the first 24hours postoperatively. Mean arterial pressure, heart rate, end-tidal concentration of sevoflurane, time to awakening, pain severity (FLACC scale), level of sedation (RAMSAY), duration of analgesia, and occurrence of adverse effects were also compared. RESULTS: Intraoperatively, there was no difference between groups regarding mean arterial pressure, heart rate, end-tidal concentration of sevoflurane, and time to awakening. Postoperative morphine consumption and pain severity were similar between groups, but the group receiving clonidine (3µg.kg-1) had lower heart rate and higher sedation level than the group receiving bupivacaine alone. CONCLUSIONS: The combination of clonidine at doses of 1, 2 or 3µg.kg-1 with bupivacaine 0.16% via caudal epidural route did not alter the consumption of morphine in the early postoperative period of children undergoing hypospadias repair.

Comparación entre dosis bajas de bupivacaína y prilocaína en cirugía perianal ambulatoria / Comparison between low doses of bupivacaine and prilocaine in ambulatory perianal surgery

La cirugía perianal ambulatoria se caracteriza por necesitar un plano anestésico profundo durante un periodo de tiempo corto. El bloqueo subaracnoideo en silla de montar consigue una anestesia sensitiva intensa sin apenas bloqueo motor asociado. Los anestésicos locales de larga duración, como la bupivacaína, permiten en dosis bajas la realización del procedimiento y el alta hospitalaria en un tiempo acorde con la dinámica de la unidad cirugía mayor ambulatoria (UCMA). La prilocaína es un anestésico local de vida media intermedia que se caracteriza por su bajo riesgo de síntomas neurológicos transitorios y que se puede usar a dosis de 10 mg en anestesia espinal en silla de montar para la realización de cirugía perianal de menos de 45 min de duración. La hipótesis planteada es que la prilocaína, al ser un anestésico de vida media más corta que la bupivacaína, proporciona un bloqueo suficiente para la realización de un procedimiento estándar de cirugía anorrectal, acortando la estancia en la UCMA. Este estudio prospectivo, a doble ciego de 100 pacientes ASA I-III, divididos en 2 grupos aleatorios: Grupo P (10 mg de prilocaína hiperbárica 20 % + 10 μg de fentanilo) y grupo B (2,5 mg bupivacaina hiperbárica 0,5 % + 10 μg de fentanilo), donde medimos como objetivo principal el tiempo desde la realización de la técnica anestésica hasta el alta hospitalaria. Y como secundarios: el éxito del bloqueo, el tiempo desde el final de la cirugía hasta el alta hospitalaria, el tiempo de regresión del bloqueo sensitivo/motor, el tiempo hasta deambulación, la retención de orina y los efectos adversos.(AU)

Ambulatory perianal surgery is characterized by the need for a deep anesthetic plane for a short period of time. The subarachnoid saddle block achieves intense sensory anesthesia with almost no associated motor blockade. Long-acting local anesthetics, such as bupivacaine, allow the procedure to be performed at low doses and discharge from the hospital in a time that is consistent with the dynamics of the major outpatient surgery unit (MOSU). Prilocaine is a local anesthetic with an intermediate half-life that is characterized by its low risk of transient neurological symptoms and can be used at a dose of 10 mg in saddle spinal anesthesia for perianal surgery of less than 45 min duration. The hypothesis put forward is that prilocaine, being a shorter half-life anesthetic than bupivacaine, provides sufficient blockade for the performance of a standard anorectal surgery procedure, shortening the stay in the AMCU. This prospective, double-blind study of 100 ASA I-III patients, divided into 2 randomized groups: group P (10 mg hyperbaric prilocaine 20 % + 10 μg of fentanyl) and group B (2.5 mg hyperbaric bupivacaine 0.5 % + 10 μg of fentanyl), where we measured as primary objective the time from the performance ofthe anesthetic technique to hospital discharge. And as secondary objectives: success of the block, time from the end of surgery to hospital discharge, time of regression of the sensory/motor block, time to ambulation, urine retention and adverse effects.(AU)

Descripción de analgesia de parto con lidocaína o bupivacaina y Apgar al nacer. Estudio observacional descriptivo retrospectivo

El trabajo de parto lleva con este la experiencia que causa uno de los dolores más intensos que se han descrito. En el Instituto de Seguridad Social de El Salvador (ISSS) se registran aproximadamente 600 a 700 partos vaginales por mes y de estos aproximadamente 10-20% solicitan analgesia para trabajo de parto, la cual el servicio de anestesia provee a través del abordaje epidural. Es conocido que se considera que el medicamento ideal para la analgesia de trabajo de parto es la bupivacaína o lidocaína 3, sin embargo, es de especial importancia describir el puntaje de APGAR de los recién nacidos de madres que recibieron cualquiera de estos dos fármacos por la vía ya mencionada. Objetivo: Determinar cómo influye el uso de lidocaína y bupivacaína como anestésico epidural sobre el puntaje APGAR posterior al nacimiento en mujeres embarazadas en fase activa del trabajo de parto con necesidad de analgesia epidural. Métodos: El presente es un estudio observacional descriptivo retrospectivo de fuentes primarias. El servicio de anestesiología del Hospital Materno Infantil Primero de Mayo cuenta con un registro sobre cuántos y a cuáles pacientes se les administra analgesia epidural por lo que el equipo investigador realizó una revisión de la técnica anestésica y se describe el Apgar al final del parto por vía vaginal en aquellas pacientes que recibieron analgesia epidural con lidocaína o bupivacaína. Se realizó el filtrado con la base de datos de Excel utilizando criterios de inclusión y exclusión, logrando incluir finalmente 81 pacientes en el análisis de los datos. Se encontró durante el escrutinio de estos que a 25 de estas se les realizó cesárea de emergencia y en 6 de estos mismos expedientes no se consignó de manera completa todos los datos necesarios para el análisis de ello, por lo que se utilizaron finalmente 51 expedientes clínicos para la realización de la presente investigación. Resultados: El APGAR promedio de los pacientes que recibieron analgesia de trabajo de parto con bupivacaína es de 8.75 y 8.9 al minuto y cinco minutos respectivamente y el promedio de APGAR alcanzado por los recién nacidos de pacientes que recibieron analgesia de trabajo de parto con lidocaína es de 9 puntos al minuto y cinco minutos. Conclusión: El promedio de APGAR en pacientes que recibieron bupivacaína es de 8.75 y el de lidocaína es de 9. (provisto por Infomedic International)

Labor brings with it the experience that causes one of the most intense pains ever described. At the Social Security Institute of El Salvador (ISSS) approximately 600 to 700 vaginal deliveries are registered per month and of these approximately 10-20% request labor analgesia, which the anesthesia service provides through the epidural approach. It is known that the ideal drug for labor analgesia is considered to be bupivacaine or lidocaine 3, however, it is of special importance to describe the APGAR score of newborns born to mothers who received either of these two drugs by the aforementioned route. Objective: To determine how the use of lidocaine and bupivacaine as epidural anesthetic influences the post-birth APGAR score in pregnant women in the active phase of labor requiring epidural analgesia. Methods: The present is a retrospective descriptive observational observational study from primary sources. The anesthesiology service of the Hospital Materno Infantil Primero de Mayo has a record of how many and to which patients epidural analgesia is administered, so the research team conducted a review of the anesthetic technique and described the Apgar at the end of vaginal delivery in those patients who received epidural analgesia with lidocaine or bupivacaine. Filtering was performed with the Excel database using inclusion and exclusion criteria, finally including 81 patients in the data analysis. It was found during the scrutiny of these that 25 of them had undergone emergency cesarean section and in 6 of these same records not all the data necessary for the analysis were completely recorded, so that 51 clinical records were finally used for the present investigation. Results: The average APGAR of the patients who received labor analgesia with bupivacaine was 8.75 and 8.9 at one minute and five minutes respectively, and the average APGAR achieved by the newborns of patients who received labor analgesia with lidocaine was 9 points at one minute and five minutes. Conclusion: The average APGAR in patients who received bupivacaine is 8.75 and that of lidocaine is 9. (provided by Infomedic International)

[Pharmacokinetic and clinical effects of two bupivacaine concentrations on axillary brachial plexus block]. / Efeitos farmacocinéticos e clínicos de duas concentrações de bupivacaína no bloqueio do plexo braquial via axilar.

INTRODUCTION: The risk of systemic bupivacaine toxicity is a persistent problem, which makes its pharmacokinetic study fundamental for regional anesthesia safety. There is little evidence of its influence on plasma peak at different concentrations. The present study compares two bupivacaine concentrations to establish how the concentration affects this drug plasma peak in axillary brachial plexus block. Postoperative latency and analgesia were also compared. METHODS: 30 patients were randomized. In the 0.25% Group, 0.25% bupivacaine (10mL) was injected per nerve. In the 0.5% Group, 0.5% bupivacaine (5mL) was injected per nerve. Peripheral blood samples were collected during the first 2hours after the blockade. For sample analyses, high performance liquid chromatography mass spectrometry was used. RESULTS: Plasma peak occurred 45minutes after the blockade, with no difference between groups at the assessed time-points. Plasma peak was 933.97 ± 328.03 ng.mL-1 (mean ± SD) in 0.25% Group and 1022.79 ± 253.81 ng.mL-1 in 0.5% Group (p = 0.414). Latency was lower in 0.5% Group than in 0.25% Group (10.67 ± 3.71 × 17.33min ± 5.30, respectively, p = 0.004). No patient had pain within the first 4hours after the blockade. CONCLUSION: For axillary brachial plexus block, there was no difference in bupivacaine plasma peak despite the use of different concentrations with the same local anesthetic mass. The concentration inversely influenced latency.

[The chondrotoxic and apoptotic effects of levobupivacaine and bupivacaine on the rabbit knee joint]. / Os efeitos condrotóxicos e apoptóticos de levobupivacaína e bupivacaína na articulação do joelho de coelhos.

BACKGROUND: A single dose injection or continuous infusion of local anesthetics into the joint space is considered to be a well-defined analgesia technique. The aim of this study was to investigate the chondrotoxic and apoptotic effects of single-dose intra-articular injection of levobupivacaine and bupivacaine on rabbit knee joint tissues. MATERIALS AND METHODS: The animals were allocated into two groups each containing 20 rabbits. 0.5% levobupivacaine (Group L) and 0.5% bupivacaine (Group B) were applied intra-articularly to the left posterior joints of rabbits. At the same time, normal saline was applied to the right posterior leg knee joints of rabbits in both groups and used as a control (Group S). At the end of the 7th and 28th days after the intraarticular injections, ten randomly chosen rabbits in each group were killed by applying intraperitoneal thiopental. Sections of cartilage tissue samples were stained for light microscopic examinations and the TUNEL method was used to investigate apoptotic cells. RESULTS: As a result of immunofluorescence microscopic examination, the number of apoptotic cells in Group B at day 7 and day 28 were both significantly higher than Group L and S (p<0.05). Also, the number of apoptotic cells in Group L at day 7 and day 28 were both significantly higher than Group S (p<0.05). CONCLUSIONS: We found that bupivacaine is more chondrotoxic than other anesthetic agent and increases the number of apoptotic cells. These results indicated that bupivacaine caused high chondrotoxic damage and it led to more apoptotic activation than levobupivacaine.

Estudio in vitro de elución de anestésicos locales en cemento óseo de PMMA / In vitro elution of local anesthetics from PMMA bone cement

Antecedentes y objetivo:Actualmente, no disponemos de un gold standard para el manejo del dolor postoperatorio tras una artroplastia total de rodilla, dado que se pueden administrar analgésicos a través de diferentes vías y ninguna de estas está exenta de riesgos. El sistema ideal de administración de analgésicos debería proporcionar dosis terapéuticas, no tóxicas, en el sitio quirúrgico, especialmente durante las primeras 72h. El cemento óseo utilizado en las artroplastias se ha usado como un medio de liberación de fármacos, especialmente antibióticos, desde 1970. Basado en este principio, se desarrolló este estudio con el objetivo de conocer el perfil de elución de dos anestésicos locales (hidrocloruro de lidocaína e hidrocloruro de bupivacaína) desde el cemento óseo de polimetilmetacrilato (PMMA). Material y métodos: Se obtuvieron especímenes de cemento óseo Palacos® R+G e hidrocloruro de lidocaína o hidrocloruro de bupivacaína según el grupo de estudio. Estos especímenes se sumergieron en PBS (por sus siglas en inglés de phosphate buffered saline) y se retiraron de la solución en diferentes cortes temporales establecidos. Posteriormente, se analizó la concentración de anestésico local en el líquido mediante cromatografía líquida. Resultados: El porcentaje de lidocaína eludida del cemento óseo PMMA de este estudio ha sido del 9,74% del contenido total de lidocaína por espécimen a las 72h y del 18,73% a las 336h (14 días). En el caso de la bupivacaína, el porcentaje de elución ha sido del 2,71% del contenido total de bupivacaína por espécimen a las 72h y del 2,70% a las 336h (14 días). Conclusiones: Los anestésicos locales eluyen in vitro desde el cemento óseo, alcanzando a las 72h dosis cercanas a las dosis utilizadas en bloqueos anestésicos.(AU)

Background and aim: Currently, we do not have a gold standard for pain management after total knee arthroplasty. We may use one of more drug delivery systems, none of which are ideal. An ideal depot delivery system would provide therapeutic, nontoxic, doses of drug at the surgical side, especially during 72h postoperatively. The bone cement used in arthroplasties has been used as a drug delivery system, especially antibiotics, since 1970. Based on this principle, we developed this study with the aim to characterize the elution profile of two local anesthetics (lidocaine hydrochloride and bupivacaine hydrochloride) from PMMA (polymethilmethacrylate) bone cement. Material and methods: Palacos® R+G bone cement and lidocaine hydrochloride or bupivacaine hydrochloride specimens were obtained depending on the study group. These specimens were immersed in PBS (phosphate buffered saline) and removed from the solution at different set times. Subsequently, the concentration of local anesthetic in the liquid was analyzed by liquid chromatography. Results: The percentage of lidocaine eluted from PMMA bone cement in this study was 9.74% of the total lidocaine content per specimen at 72h and 18.73% at 336h (14 days). In case of bupivacaine, the elution percentage was 2.71% of the total bupivacaine content per specimen at 72h and 2.70% at 336h (14 days). Conclusions: Local anesthetics elute in vitro from PMMA bone cement, reaching doses at 72h close to the doses used in anesthetic blocks.(AU)

[Translated article] In vitro elution of local anaesthetics from PMMA bone cement / Estudio in vitro de elución de anestésicos locales en cemento óseo de PMMA

Antecedentes y objetivo:Actualmente, no disponemos de un gold standard para el manejo del dolor postoperatorio tras una artroplastia total de rodilla, dado que se pueden administrar analgésicos a través de diferentes vías y ninguna de estas está exenta de riesgos. El sistema ideal de administración de analgésicos debería proporcionar dosis terapéuticas, no tóxicas, en el sitio quirúrgico, especialmente durante las primeras 72h. El cemento óseo utilizado en las artroplastias se ha usado como un medio de liberación de fármacos, especialmente antibióticos, desde 1970. Basado en este principio, se desarrolló este estudio con el objetivo de conocer el perfil de elución de dos anestésicos locales (hidrocloruro de lidocaína e hidrocloruro de bupivacaína) desde el cemento óseo de polimetilmetacrilato (PMMA). Material y métodos: Se obtuvieron especímenes de cemento óseo Palacos® R+G e hidrocloruro de lidocaína o hidrocloruro de bupivacaína según el grupo de estudio. Estos especímenes se sumergieron en PBS (por sus siglas en inglés de phosphate buffered saline) y se retiraron de la solución en diferentes cortes temporales establecidos. Posteriormente, se analizó la concentración de anestésico local en el líquido mediante cromatografía líquida. Resultados: El porcentaje de lidocaína eludida del cemento óseo PMMA de este estudio ha sido del 9,74% del contenido total de lidocaína por espécimen a las 72h y del 18,73% a las 336h (14 días). En el caso de la bupivacaína, el porcentaje de elución ha sido del 2,71% del contenido total de bupivacaína por espécimen a las 72h y del 2,70% a las 336h (14 días). Conclusiones: Los anestésicos locales eluyen in vitro desde el cemento óseo, alcanzando a las 72h dosis cercanas a las dosis utilizadas en bloqueos anestésicos.(AU)

Background and aim: Currently, we do not have a gold standard for pain management after total knee arthroplasty. We may use one of more drug delivery systems, none of which are ideal. An ideal depot delivery system would provide therapeutic, nontoxic, doses of drug at the surgical side, especially during 72h postoperatively. The bone cement used in arthroplasties has been used as a drug delivery system, especially antibiotics, since 1970. Based on this principle, we developed this study with the aim to characterize the elution profile of two local anesthetics (lidocaine hydrochloride and bupivacaine hydrochloride) from PMMA (polymethilmethacrylate) bone cement. Material and methods: Palacos® R+G bone cement and lidocaine hydrochloride or bupivacaine hydrochloride specimens were obtained depending on the study group. These specimens were immersed in PBS (phosphate buffered saline) and removed from the solution at different set times. Subsequently, the concentration of local anesthetic in the liquid was analyzed by liquid chromatography. Results: The percentage of lidocaine eluted from PMMA bone cement in this study was 9.74% of the total lidocaine content per specimen at 72h and 18.73% at 336h (14 days). In case of bupivacaine, the elution percentage was 2.71% of the total bupivacaine content per specimen at 72h and 2.70% at 336h (14 days). Conclusions: Local anesthetics elute in vitro from PMMA bone cement, reaching doses at 72h close to the doses used in anesthetic blocks.(AU)

Anestesia multimodal intratecal en cesáreas, cambios que mejoran su eficacia y seguridad: ensayo clínico / Intrathecal multimodal anesthesia in caesarean sections, changes that improve its efficacy and safety: clinical trial

Resumen: Introducción: la concentración y velocidad en la administración de la anestesia multimodal intratecal con fentanilo en cesáreas mejoran la eficacia anestésica manteniendo buen control hemodinámico. Objetivo: evaluar si algunos cambios en la anestesia multimodal intratecal mejoran su eficacia y seguridad en cesáreas. Material y métodos: ensayo clínico, controlado, aleatorizado, doble ciego en mujeres embarazadas programadas para cesárea, distribuidas en tres grupos: grupo F6B2: fentanilo 65 μg + bupivacaína hiperbárica 2.5 mg + morfina 10 μg + dexmedetomidina 5 μg; grupo F6B3: fentanilo 60 μg + bupivacaína hiperbárica 3 mg+ morfina 100 μg+ dexmedetomidina 5 μg; y grupo F7B2: fentanilo 70 μg + bupivacaína hiperbárica 2 mg + morfina 100 μg + dexmedetomidina 5 μg. Se evaluó la eficacia anestésica previo a la incisión, durante la disección de la pared abdominal, al ingreso a cavidad abdominal, en la revisión de correderas parietocólicas y en el postquirúrgico inmediato, así como los signos vitales. Resultados: los grupos F6B2 y F6B3 resultaron tener mayor eficacia anestésica en la revisión de correderas parietocólicas (p = 0.02) y el grupo F7B2 el de mayor seguridad con mejor control hemodinámico a los minutos 1 y 10 (p = 0.03 y p = 0.03 respectivamente). Conclusiones: los cambios en la administración de la anestesia multimodal intratecal con fentanilo mejoraron la eficacia anestésica, pero disminuyen la seguridad sobre el control hemodinámico.

Abstract: Introduction: the concentration and speed in the administration of intrathecal multimodal anesthesia with fentanyl in cesareans section improve anesthetic efficacy while maintaining good hemodynamic control. Objective: to evaluate if some changes in intrathecal multimodal anesthesia improve its efficacy and safety in cesareans section. Material and methods: clinical trial, controlled, randomized, double blind; in pregnant women scheduled for cesarean section, divided into 3 groups: group F6B2: fentanyl 65 μg + hyperbaric bupivacaine 2.5 mg+ morphine 100 μg+ dexmedetomidine 5 μg; group F6B3: fentanyl 60 μg + hyperbaric bupivacaine 3 mg + morphine 100 μg + dexmedetomidine 5 μg; and group F7B2: fentanyl 70 μg + hyperbaric bupivacaine 2 mg + morphine 100 μg + dexmedetomidine 5 μg. The anesthetic efficacy was evaluated prior to the incision, during the dissection of the abdominal wall, upon the admission to the abdominal cavity, in the review of paracolic slides and in the immediate postoperative period, as well as the vital signs. Results: the F6B2 and F6B3 groups turned out to have greater anesthetic efficacy in the revision of paracolic slides (p = 0.02) and the F7B2 group had the highest safety with better hemodynamic control at 1 and 10 minutes (p = 0.03 and p = 0.03, respectively). Conclusions: changes in the administration of intrathecal multimodal anesthesia with fentanyl improved anesthetic efficacy, but decreased safety over hemodynamyc control.

[Ultrasound-guided transversus abdominis plane block in patients undergoing laparoscopic cholecystectomy: comparison of efficacy of bupivacaine and levobupivacaine on postoperative pain control]. / Bloqueio do plano abdominal transverso guiado por ultrassom em pacientes submetidos à colecistectomia laparoscópica: comparação da eficácia de bupivacaína e levobupivacaína no controle da dor pós­operatória.

BACKGROUND AND OBJECTIVE: The use of transversus abdominis plane block with different local anesthetics is considered as a part of multimodal analgesia regimen in laparoscopic cholecystectomy patients. However no studies have been published comparing bupivacaine and levobupivacaine for transversus abdominis plane block. We aimed to compare bupivacaine and levobupivacaine in ultrasound-guided transversus abdominis plane block in patients undergoing laparoscopic cholecystectomy. METHODS: Fifty patients (ASA I/II), undergoing laparoscopic cholecystectomy were randomly allocated into two groups. Following anesthesia induction, ultrasound-guided bilateral transversus abdominis plane block was performed with 30mL of bupivacaine 0.25% in Group B (n=25) and 30mL of levobupivacaine 0.25% in Group L (n=25) for each side. The level of pain was evaluated using 10cm visual analog scale (VAS) at rest and during coughing 1, 5, 15, 30min and 1, 2, 4, 6, 12 and 24h after the operation. When visual analogue scale>3, the patients received IV tenoxicam 20mg. If visual analogue scale remained >3, they received IV. tramadol 1mg.kg-1. In case of inadequate analgesia, a rescue analgesic was given. The analgesic requirement, time to first analgesic requirement was recorded. RESULTS: Visual analogue scale levels showed no difference except first and fifth minutes postoperatively where VAS was higher in Group L (p<0.05). Analgesic requirement was similar in both groups. Time to first analgesic requirement was shorter in Group L (4.35±6.92min vs. 34.91±86.26min, p=0.013). CONCLUSIONS: Bupivacaine and levobupivacaine showed similar efficacy at TAP block in patients undergoing laparoscopic cholecystectomy.