Associacao de opioides lipofilicos a bupivacaina na anestesia peridural. Ha vantagem no aumento da dose do opioide?

Background and Objectives: - The effects of associating lipophilic opioids to local anesthetics in epidural anesthesia are not well defined. There are still questions and controversies about opioid doses to be used and their major effects in the epidural block. This study aimed at evaluating the epidural block effects in humans of the association of different fentanyl and sufentanil doses to bupivacaine with 1:200.000 epinephrine. Methods: - A double-blind randomized study was performed in 94 patients of both genders, physical status ASA I, aged between 18 and 60 years, submitted to lower abdomen, perineal or lower limb surgery. Patients without preanesthetic medication were epidurally injected with 100 mg (20 ml) 0.5% bupivacaine, 0.1 mg (0.1 ml) 1%o epinephrine plus a combination of the following drugs: BUPI Group (15 patients): 2 ml of 0.9% saline solution (SS); FENT50 Group (19 patients): 50 μg (1 ml) fentanyl + 1 ml SS; FENT100 Group (20 patients): 100 μg (2 ml) fentanyl; SUF30 Group (20 patients): 30 μg (0.6 ml) sufentanil + SS (1.4 ml); SUF100 Group (20 patients): 50 μg (1 ml) sufentanil + SS (1 ml). The following parameters were studied: onset of sensory block, analgesic block (onset time) in T12, T10 and T8, analgesic block duration in T10 and T12, motor block degree, consciousness degree, need for supplemental perioperative sedation and analgesia, hypotension, bradycardia and peri and post operative side-effects, analgesia duration, proportion of patients needing supplemental analgesia and evaluation of postoperative pain (pain analog visual scale). Results: Groups were demographically uniform. The addition of fentanyl or sufentanil did not alter major characteristics of perioperative epidural block and has not significantly increased postoperative analgesia duration as compared to the use of bupivacaine only. However, the addition of lipophilic opioids has increased the quality of perioperative anesthetic block, translated into a lesser need for supplemental analgesia (p < 0.02). The increased dose of fentanyl and especially of sufentanil has increased the incidence of perioperative drowsiness (p < 0.001) without significant increase in other side effects. Conclusions: In the conditions and doses used, the addition of lipophilic opioids to bupivacaine and the increased dose of lipophilic opioids have improved anesthetic block quality without changes in the epidural block characteristics or a significant increase in side effects, with the exception of drowsiness mainly caused by sufentanil. However, they were not able to provide a significant increase in postoperative analgesia duration.

Bupivacaína, Ropivacaína e Levobupivacaína em Analgesia e Anestesia de Parto. Repercussões Materno-Fetais

Background and Objectives - Bupivacaine has been a very useful local anesthetic in Obstetrics in spite of its potential cardiotoxicity. In obstetric analgesia, ropivacaine is preferred to bupivacaine, and levobupivacaine is less cardiotoxic than the racemic mixture. The aim of this study was to compare the maternal-fetal effects of bupivacaine, ropivacaine and levobupivacaine in obstetric analgesia and anesthesia. Methods - Participated in this study 33 term pregnant women, physical status ASA I and II submitted to epidural anesthesia who received 18.75 mg (in 15 ml completed with 9% saline) of: GI - bupivacaine, GII - ropivacaine, and GIII - levobupivacaine. Pain intensity, sensory block level, onset time, quality of analgesia, motor block intensity, analgesia duration and time for labor resolution were evaluated. For vaginal delivery, 40 mg (in 8 ml of saline) of the same local anesthetic were used; for cesarean delivery, the dose has been mg in 20 ml solution. Newborns of these mothers were evaluated through the Apgar score in minutes 1, 5 and 10, and through the Amiel-Tison method (neurologic and adaptative capacity score - NACS) at 30 min, 2 h, and 24 h. Results - There were no significant statistical differences among groups as to sensory block level, onset time, quality of analgesia, labor analgesia duration, time for labor resolution, and Apgar scores at minute 1. Ast to motor block, GIII > GII and GI was intermediary. In relation to pain intensity, there was a trend for GI > GIII. For Apgar scores in minute 5, GII > (GI = GIII), and in minute 10 (GI = GII) < GIII. NACS at 2 h showed, GII > GI > GIII, and at 24 h, GII > GIII > GI. Conclusions - Ropivacaine has relieved maternal pain with less motor block. Newborns of GII mothers (ropivacaine) showed the best Apgar and NACS scores.

Efeitos adversos do sufentanil associado ao anestésico local pelas vias subaracnóidea e peridural em pacientes submetidas à analgesia de parto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Myocardial contractility impairment with racemic bupivacaine, non-racemic bupivacaine and ropivacaine. A comparative study

To study racemic bupivacaine, non-racemic bupivacaine and ropivacaine on myocardial contractility. Isolated Wistar papillary muscles were submitted to 50 and 100 mM racemic bupivacaine (B50 and B100), non-racemic bupivacaine (NR50 and NR100) and ropivacaine (R50 and R100) intoxication. Isometric contraction data were obtained in basal condition (0.2 Hz), after increasing the frequency of stimulation to 1.0 Hz and after 5, 10 and 15 min of local anesthetic intoxication. Data were analyzed as relative changes of variation. Developed tension was higher with R100 than B100 at D1 (4.3 ± 41.1 vs -57.9 ± 48.1). Resting tension was altered with B50 (-10.6 ± 23.8 vs -4.7 ± 5.0) and R50 (-14.0 ± 20.5 vs -0.5 ± 7.1) between D1 and D3. Maximum rate of tension development was lower with B100 (-56.6 ± 38.0) than R50 (-6.3 ± 37.9) and R100 (-1.9 ± 37.2) in D1. B50, B100 and NR100 modified the maximum rate of tension decline from D1 through D2. Time to peak tension was changed with NR50 between D1 and D2. Racemic bupivacaine depressed myocardial contractile force more than non-racemic bupivacaine and ropivacaine. Non-racemic and racemic bupivacaine caused myocardial relaxation impairment more than ropivacaine.

Preliminary clinical assessment of polyvinyl alcohol-tetrahydroxyborate hydrogels as potential topical formulations for local anesthesia of lacerations

The aim of this study was to assess a novel semisolid material as a potential topical drug delivery system for acute laceration. The objectives were to correlate physical characterization data using rheologic studies and to compare with clinical assessment of performance in an emergency department (ED).

Effects of Local Anesthetic on the Time Between Analgesic Boluses and the Duration of Labor in Patient-Controlled Epidural Analgesia: Prospective Study of Two Ultra-Low Dose Regimens of Ropivacaine and Sufentanil

BACKGROUND: Patient-controlled epidural analgesia with low concentrations of anesthetics is effective in reducing labor pain. The aim of this study was to assess and compare two ultra-low dose regimens of ropivacaine and sufentanil (0.1% ropivacaine plus 0.5 μg.ml-1 sufentanil vs. 0.06% ropivacaine plus 0.5 μg.ml-1 sufentanil) on the intervals between boluses and the duration of labor. MATERIAL AND METHODS: In this non-randomized prospective study, conducted between January and July 2010, two groups of parturients received patient-controlled epidural analgesia: Group I (n = 58; 1 mg.ml-1 ropivacaine + 0.5 μg.ml-1 sufentanil) and Group II (n = 57; 0.6 mg.ml-1 ropivacaine + 0.5 μg.ml-1 sufentanil). Rescue doses of ropivacaine at the concentration of the assigned group without sufentanil were administered as necessary. Pain, local anesthetic requirements, neuraxial blockade characteristics, labor and neonatal outcomes, and maternal satisfaction were recorded. RESULTS: The ropivacaine dose was greater in Group I (9.5 [7.7-12.7] mg.h-1 vs. 6.1 [5.1-9.8 mg.h-1], p < 0.001). A time increase between each bolus was observed in Group I (beta = 32.61 min, 95% CI [25.39; 39.82], p < 0.001), whereas a time decrease was observed in Group II (beta = -1.40 min, 95% CI [-2.44; -0.36], p = 0.009). The duration of the second stage of labor in Group I was significantly longer than that in Group II (78 min vs. 65 min, p < 0.001). CONCLUSIONS: Parturients receiving 0.06% ropivacaine exhibited less evidence of cumulative effects and exhibited faster second stage progression than those who received 0.1% ropivacaine.

Interação entre a analgesia de parto e o seu resultado: avaliação pelo peso e índice de Apgar do recém-nascido

JUSTIFICATIVA E OBJETIVOS: Existem controvérsias quanto à possibilidade de a analgesia de parto interferir no andamento do trabalho de parto e na vitalidade do recém-nascido. O objetivo deste estudo foi a interação entre analgesia do parto pelas técnicas peridural contínua e duplo bloqueio, com pequena dose de anestésico local, e o tipo de parto ocorrido, pela análise do peso e índice de Apgar do recém-nascido. MÉTODO: Analisaram-se, prospectivamente, os resultados de 168 analgesias de parto (janeiro de 2002 a janeiro de 2003), divididas em quatro grupos: G1 (n = 58) peridural contínua e evolução para parto vaginal; G2 (n = 69) duplo bloqueio e evolução para parto vaginal; G3 (n = 25) peridural contínua e evolução para cesariana; G4 (n = 16) duplo bloqueio e evolução para cesariana. Para G1 foi administrada ropivacaína a 0,125% (12 a 15 mL), para G2, bupivacaína a 0,5% (0,5 a 1 mL), sufentanil (10 mg), por via subaracnóidea. Administrou-se ropivacaína a 0,5%, por via peridural, para o parto vaginal (8 mL) e para cesariana (20 mL). Avaliaram-se idade, peso, altura, índice de massa corpórea (IMC), idade gestacional (IG), paridade e complicações (hipotensão arterial, bradicardia e hipóxia), e, do recém-nascido, peso e índice de Apgar (1º, 5º e 10º min). RESULTADOS: A maioria das parturientes era primigesta, com gestação de termo (uma IG de 28 semanas e nenhum pós-datismo), com peso, G2 < G4, e, IMC, G2 £ G4. Para o peso do RN, G1 < G3 e G2 < G4, e o Apgar do 1º min, G1 > G3. CONCLUSÕES: As técnicas de analgesia, peridural contínua e duplo bloqueio, com pequenas doses de anestésico local, não apresentaram interação com o resultado do parto, se a análise estiver focalizada no peso e no índice de Apgar do recém-nascido.

Estudo comparativo do bloqueio combinado femoral-isquiático, por punção em sítio único, com anestesia subaracnóidea para cirurgia unilateral do membro inferior

JUSTIFICATIVA E OBJETIVOS: A raquianestesia unilateral pode apresentar vantagens em pacientes ambulatoriais. O objetivo deste trabalho foi comparar a raquianestesia unilateral com o bloqueio combinado femoral-isquiático em cirurgias ortopédicas unilaterais e ambulatoriais. MÉTODO: Sessenta pacientes foram aleatoriamente separados em dois grupos para receber 6 mg de bupivacaína hiperbárica ou hipobárica (grupo RQ) em decúbito lateral esquerdo ou 800 mg de lidocaína 1,6% com epinefrina nos nervos femoral e isquiático (grupo CFI) em decúbito dorsal. O bloqueio dos nervos foi realizado com agulha de 150 mm conectada a um neuroestimulador e inserida no ponto médio entre as duas abordagens clássicas, sendo injetados 15 mL no nervo femoral e 35 mL no nervo isquiático. Avaliados o tempo para realização dos bloqueios e sua duração. Vinte minutos após, os pacientes foram avaliados em relação aos bloqueios sensitivo e motor. RESULTADOS: O tempo para a realização da raquianestesia foi significativamente menor do que o bloqueio combinado femoral-isquiático. O bloqueio unilateral foi obtido em 90% dos pacientes no grupo RQ e 100% no grupo CFI. O tempo para recuperação do bloqueio sensitivo e motor foi significativamente maior no grupo CFI. Não houve bradicardia ou hipotensão. CONCLUSÕES: Este estudo conclui que é tecnicamente fácil realizar bloqueio anterior combinado femoral-isquiático e pode ser uma alternativa para o bloqueio unilateral do membro inferior. A raquianestesia unilateral com baixas doses de bupivacaína resultou em menor tempo para realização, menor número de tentativas e recuperação mais precoce do bloqueio combinado femoral-isquiático, porém com mesma efetividade.

Comparative analysis of tissue reactions to anesthetic solutions: histological analysis in subcutaneous tissue of rats.

Postanesthetic pain is a relatively common complication after local anesthesia. This complication may be caused by the anesthetic technique or by the anesthetic solution used. Tissue reactions induced by the anesthetic solutions may be one of the factors resulting in pain after anesthesia. The objective of this study was to comparatively analyze tissue reactions induced by different anesthetic solutions in the subcutaneous tissue of rats. The following solutions were utilized: 2% lidocaine without vasoconstrictor; a 0.5% bupivacaine solution with 1:200,000 adrenaline; a 4% articaine solution and 2% mepivacaine, both with 1:100,000 adrenaline; and a 0.9% sodium chloride solution as a control. Sterilized absorbent paper cones packed inside polyethylene tubes were soaked in the solutions and implanted in the subcutaneous region. The sacrifice periods were 1, 2, 5, and 10 days after surgery. The specimens were prepared and stained with hematoxylin and eosin for histological analysis. The results showed that there is a difference in tissue irritability produced by the local anesthetic solutions. The results also showed that there is no relation between the concentration of the drug and the inflammatory intensity, that the mepivacaine and articaine solutions promoted less inflammatory reaction than the bupivacaine, and that the lidocaine solution produced the least intense inflammation.

Efeito da lavagem peritoneal com bupivacaína na sobrevida de ratos com peritonite fecal

BACKGROUND AND OBJECTIVES: Based on the knowledge of the anti-inflammatory and anti-bacterial actions of local anesthetics (LA), the objective of this study was to determine the effects of peritoneal lavage with bupivacaine on survival of mice with fecal peritonitis. METHODS: Forty-eight Wistar mice, weighing between 300 and 330 g (311.45 ± 9.67 g), undergoing laparotomy 6 hours after induction of peritonitis were randomly divided in 4 groups: 1 - Control, without treatment (n = 12); 2 - Drying of the abdominal cavity (n = 12); 3 - Lavage with 3 mL NS and posterior drying of the abdominal cavity (n = 12); and 4 - Lavage with 8 mg.kg -1 (± 0.5 mL) of 0.5% bupivacaine added to 2.5 mL of NS followed by drying out of the abdominal cavity (n = 12). Animals that died underwent necropsy and the time of death was recorded. Surviving animals were killed on the 11 th postoperative day and underwent necropsy. RESULTS: Group 1 presented a 100% mortality rate in 52 hours, 100% mortality rate in Group 2 in 126 hours, and Group 3 presented a 50% mortality rate in 50 hours. Animals in Group 4 survived. Survival on the 11 th day was greater in groups 3 and 4 than in Groups 1 and 2 (p < 0.001) and greater in Group 4 than in Group 3 (p < 0.01). CONCLUSIONS: Peritoneal lavage with a solution of bupivacaine diluted in NS was effective in preventing death for 11 days in 100% of animals with fecal peritonitis. © Sociedade Brasileira de Anestesiologia, 2008.

Preparation and characterization of poly(ε-caprolactone) nanospheres containing the local anesthetic lidocaine

The objective of this work was to develop a modified release system for the local anesthetic lidocaine (LDC), using poly(ε-caprolactone) (PCL) nanospheres (NSs), to improve the pharmacological properties of the drug when administered by the infiltration route. In vitro experiments were used to characterize the system and investigate the release mechanism. The NSs presented a polydispersion index of 0.072, an average diameter of 449.6nm, a zeta potential of -20.1mV, and an association efficiency of 93.3%. The release profiles showed that the release of associated LDC was slower than that of the free drug. Atomic force microscopy analyses showed that the spherical structure of the particles was preserved as a function of time, as well as after the release experiments. Cytotoxicity and pharmacological tests confirmed that association with the NSs reduced the toxicity of LDC, and prolonged its anesthetic action. This new formulation could potentially be used in applications requiring gradual anesthetic release, especially dental procedures. © 2012 Wiley Periodicals, Inc.

Comparative efficacy of 2 topical anesthetics for the placement of orthodontic temporary anchorage devices.

This study compared the effectiveness of topical benzocaine 20% versus a combination of lidocaine, tetracaine, and phenylephrine in providing sufficient analgesia for the placement of orthodontic temporary anchorage devices (TADs). The 2 topical anesthetics were tested against each other bilaterally using a randomized, double-blind, crossover design. The agents were left in place for the amount of time prescribed by the manufacturer. The TAD was then placed, and each subject rated the degree of pain on a Heft-Parker visual analogue scale. A pulse oximeter was used to record the preoperative and postoperative pulse rates. Statistically significant differences in perceived pain (P < .05) and success rate (P < .01) between drugs were seen, but no significant difference in pulse rate change between the topical anesthetics was observed (P > .05). It was concluded that when the efficacy of topical benzocaine and of a combination product was compared as the sole anesthetic to facilitate acceptable pain control for placement of orthodontic temporary anchorage devices, the combination product was considerably more efficacious.

Reversible inactivation of macaque frontal eye field.

The macaque frontal eye field (FEF) is involved in the generation of saccadic eye movements and fixations. To better understand the role of the FEF, we reversibly inactivated a portion of it while a monkey made saccades and fixations in response to visual stimuli. Lidocaine was infused into a FEF and neural inactivation was monitored with a nearby microelectrode. We used two saccadic tasks. In the delay task, a target was presented and then extinguished, but the monkey was not allowed to make a saccade to its location until a cue to move was given. In the step task, the monkey was allowed to look at a target as soon as it appeared. During FEF inactivation, monkeys were severely impaired at making saccades to locations of extinguished contralateral targets in the delay task. They were similarly impaired at making saccades to locations of contralateral targets in the step task if the target was flashed for < or =100 ms, such that it was gone before the saccade was initiated. Deficits included increases in saccadic latency, increases in saccadic error, and increases in the frequency of trials in which a saccade was not made. We varied the initial fixation location and found that the impairment specifically affected contraversive saccades rather than affecting all saccades made into head-centered contralateral space. Monkeys were impaired only slightly at making saccades to contralateral targets in the step task if the target duration was 1000 ms, such that the target was present during the saccade: latency increased, but increases in saccadic error were mild and increases in the frequency of trials in which a saccade was not made were insignificant. During FEF inactivation there usually was a direct correlation between the latency and the error of saccades made in response to contralateral targets. In the delay task, FEF inactivation increased the frequency of making premature saccades to ipsilateral targets. FEF inactivation had inconsistent and mild effects on saccadic peak velocity. FEF inactivation caused impairments in the ability to fixate lights steadily in contralateral space. FEF inactivation always caused an ipsiversive deviation of the eyes in darkness. In summary, our results suggest that the FEF plays major roles in (1) generating contraversive saccades to locations of extinguished or flashed targets, (2) maintaining contralateral fixations, and (3) suppressing inappropriate ipsiversive saccades.

The use of topical anaesthesia during repair of minor lacerations in Departments of Emergency Medicine:a literature review

There are currently a number of different methods available to obtain anaesthesia in minor dermatological procedures. Although intradermal infiltration of 1% lidocaine is the favoured method for anaesthesia induction in laceration repair, it can cause significant pain in itself. Topical anaesthesia has been investigated as an alternative to infiltration anaesthesia, with the majority of studies looking at preparations of either TAC (tetracaine, adrenaline and cocaine) or LAT (lidocaine, adrenaline and tetracaine).

A Non-Inferiority Randomized Controlled Trial Comparing the Clinical Effectiveness of Anesthesia Obtained by Application of a Novel Topical Anesthetic Putty With the Infiltration of Lidocaine for the Treatment of Lacerations in the Emergency Department

We test the hypothesis that anesthesia, measured as pain scores, induced by a novel topical anesthetic putty is non-inferior (margin=1.3) to that provided by conventional lidocaine infiltration for the repair of lacerations.