Estudo comparativo entre bupivacaína racêmica (S50-R50) a 0,125% e bupivacaína em excesso enantiomérico de 50% (S75-R25) a 0,125% e 0,25% em anestesia peridural para analgesia de parto

Abstract

RESUMODuarte NMC, Caetano AMM, Lima LC, Chagas AS -Estudo Comparativo entre Bupivacaína Racêmica (S50-R50) a 0,125% e Bupivacaína em Excesso Enantiomérico de 50% (S75-R25) a 0,125% e 0,25% em Anestesia Peridural para Analgesia de Parto. JUSTIFICATIVA E OBJETIVOS:A peridural contínua é utilizada para alívio da dor do trabalho de parto e associada a baixos índices de complicações. Estudos com enantiômeros levógiros dos anestésicos locais demonstraram maior segurança em função de menor cardiotoxicidade. O objetivo deste estudo foi comparar a analgesia e o bloqueio motor entre a bupivacaína (S50-R50) a 0,125% e a bupivacaína em excesso enantiomérico de 50% (S75-R25) a 0,125% e 0,25% em peridural contínua para analgesia de parto. MÉTODO:Realizou-se ensaio clínico duplamente encoberto, com distribuição aleatória de 75 participantes em trabalho de parto, distribuídas em três grupos: GI -bupivacaína (S50-R50) a 0,125%; GII -bupivacaína (S75-R25) a 0,125%; e GIII -bupivacaína (S75-R25) a 0,25%. A inclusão no estudo foi feita após assinatura do Consentimento Livre e Esclarecido. RESULTADOS:Não foram encontradas diferenças estatísticas significativas quanto à latência da analgesia, nível sensorial do bloqueio, volume de anestésico local, duração do trabalho de parto e da analgesia, freqüência de parto instrumental, escores de Apgar ou pH do cordão umbilical. O intervalo para a primeira dose resgate foi maior e os escores de dor em 45 min foram menores no grupo bupivacaína (S75-R25) a 0,25%. A intensidade do bloqueio motor foi maior no grupo bupivacaína (S50-R50) a 0,125%. CONCLUSÕES:A bupivacaína (S75-R25) determinou um bloqueio motor menos intenso, mesmo quando utilizada em maior concentração (0,25%), resultando em melhor qualidade de analgesia, sem interferir na evolução do trabalho de parto ou na vitalidade dos recém-nascidos.Unitermos: ANALGESIA: parto; ANESTÉSICOS, Local: bupivacaína racêmica, bupivacaína em excesso enantiomérico, levobupivacaína; TÉCNICAS ANESTÉSICAS, Regional: peridural contínua. SUMMARYDuarte NMC, Caetano AMM, Lima LC, Chagas AS -A Comparative Study of 0.125% Racemic Bupivacaine (S50-R50) and 0.125% and 0.25% 50% Enantiomeric Excess Bupivacaine (S75-R25) in Epidural Anesthesia for Labor Analgesia. BACKGROUND AND OBJECTIVES:Continuous epidural block is used for relief of labor pain and it is associated with a low incidence of complications. Studies with the levorotatory isomer of local anesthetics demonstrated that they are safer regarding the cardiotoxicity. The objective of this study was to compare analgesia and motor blockade of 0.125% bupivacaine (S50-R50) and 0.125% and 0.25% 50% enantiomeric excess bupivacaine (S75-R25) in continuous epidural block for labor analgesia. METHODS:Seventy-five patients in labor participated in this randomized, double-blind study after signing an informed consent. Patients were divided in three groups: GI -0.125% bupivacaine (S50-R50); GII -0.125% bupivacaine (S75-R25) and GIII -0.25% bupivacaine (S75-R25). RESULTS:The latency of analgesia, levels of sensorial blo...

Estudo comparativo entre bupivacaína (S75-R25) e ropivacaína em bloqueio peridural para analgesia de parto

“…Those results are conflicting with ours since when analyzing the motor blockade we observed that it was similar in both bupivacaine (S75-R25) and ropivacaine groups because there is a predominance of levorotatory isomers in both solutions 13 . Despite in vitro studies having suggested that both isomers of bupivacaine are equipotent for the motor blockade 20 , a more recent in vitro study indicated that that the dextrorotatory is more potent than the levorotatory in inhibiting sodium channels 21 , justifying the presence of lower motor blockade when a mixture with greater concentration o the S isomer is used.…”

“…The present study demonstrated a tendency towards a lower latency in the bupivacaine (S75-R25) group, which might be advantageous in situations in which fast pain relief is desirable such as labor 13 .…”

“…The literature has demonstrated that the administration of epidural bupivacaine (S75-R25) is associated with lower intensity of motor blockade 8,9 , besides preserving the differential blockade of racemic bupivacaine, representing an advantage of its use in labor analgesia 10,11,12,13 . Parturientss who participated in this study received 0.25% bupivacaine (S75-R25) and 0.20% ropivacaine.…”

“…Note that the pharmacological profile of anesthetics with greater proportion of the levorotatory isomer allows increasing its concentration with little change in the intensity of the motor blockade 13 .…”

A Randomised Controlled Trial to Evaluate the Effectiveness of Intrathecal Bupivacaine Combined with Different Adjuvants (Fentanyl, Clonidine and Dexmedetomidine) in Caesarean Section

“…Spinal anesthesia performed with fine gauge disposable needles and administration of bupivacaine combined with adjuvant drugs into the subarachnoid space, is reported as effective technique in most caesarean sections [20][21][22]. Previous studies have indicated that administration of epidural bupivacaine in labor analgesia is an advantage because it is coupled with lower intensity of motor blockade [23,24] besides preserving the differential blockade of racemic bupivacaine [25][26][27][28]. The aim of this perspective, double blind randomized study was to evaluate and compare the effectiveness of bupivacaine-fentanyl, bupivacaineclonidine and bupivacaine-dexmetomodine on the quality of blockade and maternal and neonatal repercussions.…”