The effect of epidural bupivacaine on vecuronium-induced neuromuscular blockade in children

[Influence of different local anesthetics on atracurium neuromuscular blockade on rats]

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.

Epidural administration of ropivacaine and its effects on the pharmacodynamics of rocuronium: Randomized controlled trial. Interaction between ropivacaine and rocuronium

Background:

Potentiation of neuromuscular blocking agents by local anesthetics has been described in various clinical and experimental studies. This study assessed the influence of epidural ropivacaine on pharmacodynamic characteristics of rocuronium.

Design:

This was a prospective randomized clinical trial at the women's hospital, an university tertiary hospital in Brazil. Sixty-two patients underwent elective abdominal surgeries requiring general anesthesia.

Intervention:

Patients were distributed into two groups: Group 1 (general anesthesia and epidural anesthesia) and Group 2 (general anesthesia). In Group 1, 0.2% ropivacaine at a dose of 40 mg (20 ml) was associated with 2 mg (2 ml) of morphine in a single epidural injection. The following parameters were assessed: clinical duration (DC₂₅) and time for recovery of the train-of-four (TOF) 0.9 ratio (T4/T1 = 90%) after an initial 0.6 mg/kg dose of rocuronium. The primary outcomes were DC₂₅ and TOF 0.9 ratio (T4/T1 = 90%). Secondary outcomes were total propofol and remifentanil consumption.

Results:

Values were presented as median and interquartile range. The results for DC₂₅ and TOF 0.9 of rocuronium were, respectively, 41.5 35.0–55.0 (25.0–63.0) in Group 1 and 44.0 37.0-51.0 (20.0–67.0) in Group 2 (P = 0.88); 88.0 67.0–99.0 (43.0–137.0) in Group 1; and 80.0 71.0-86.0 (38.0–155.0) in Group 2 (P = 0.83). There was no significant difference between the groups, in terms of pharmacodynamic characteristics of rocuronium. Propofol consumption did not show any difference between the groups. However, remifentanil consumption was significantly lower in Group 1 (P < 0.01).

Conclusion:

Epidural ropivacaine, in the dose studied, did not prolong the duration of rocuronium-induced neuromuscular blockade.

Trial Registry Number:

ReBEC (ref: RBR-7cyp6t).

[Effect of ropivacaine combined with pancuronium on neuromuscular transmission and effectiveness of neostigmine and 4-aminopyridine for blockade reversal: experimental study]

BACKGROUND AND OBJECTIVES

The local anesthetic effects on neuromuscular junction and its influence on blockade produced by nondepolarizing neuromuscular blockers are still under-investigated; however, this interaction has been described in experimental studies and in humans. The aim of this study was to evaluate in vitro the interaction between ropivacaine and pancuronium, the influence on transmission and neuromuscular blockade, and the effectiveness of neostigmine and 4-aminopyridine to reverse the blockade.

METHODS

Rats were divided into groups (n=5) according to the study drug: ropivacaine (5μgmL(-1)); pancuronium (2μg.mL(-1)); ropivacaine+pancuronium. Neostigmine and 4-aminopyridine were used at concentrations of 2μgmL(-1) and 20μgmL(-1), respectively. The effects of ropivacaine on membrane potential and miniature end-plate potential, the amplitude of diaphragm responses before and 60minutes after the addition of ropivacaine (degree of neuromuscular blockade with pancuronium and with the association of pancuronium-ropivacaine), and the effectiveness of neostigmine and 4-aminopyridine on neuromuscular block reversal were evaluated.

RESULTS

Ropivacaine did not alter the amplitude of muscle response (the membrane potential), but decreased the frequency and amplitude of the miniature end-plate potential. Pancuronium blockade was potentiated by ropivacaine, and partially and fully reversed by neostigmine and 4-aminopyridine, respectively.

CONCLUSIONS

Ropivacaine increased the neuromuscular block produced by pancuronium. The complete antagonism with 4-aminopyridine suggests presynaptic action of ropivacaine.

Do bupivacaine, clindamycin, and gentamicin at their clinical concentrations enhance rocuronium-induced neuromuscular block?

Background

Bupivacaine, clindamycin, and gentamicin inhibit neuromuscular (NM) conduction. When they are combined, they may synergistically reduce the effective concentration of each to the therapeutic concentration in augmenting rocuronium-induced NM block. Thus, the aim of this study was to investigate whether combinations of the three drugs, at around their therapeutic concentrations, potentiate rocuronium-induced NM block.

Methods

Fifty-seven left-phrenic nerve hemidiaphragms (Male S-D rats, 150-250 g) were hung in a 20-ml organ bath filled with Krebs solution. Three consecutive single-twitch tensions (0.1 Hz) and one tetanic tension (50 Hz for 1.9 s) were obtained. A Krebs solution was premixed with concentration sets of bupivacaine and clindamycin, bupivacaine and gentamicin, or bupivacaine, clindamycin and gentamicin. Then, the concentration of rocuronium was cumulatively increased in the Krebs solution (1, 3, 5, 7, 9, 12, 14, 16, 18, and 20 µM) until an 80% to 90% reduction in single twitch was attained. The effective concentrations for each experiment were determined with the probit model.

Results

The combinations of bupivacaine, clindamycin, and gentamicin enhanced rocuronium-induced NM block. When the three drugs were applied simultaneously, their concentrations were reduced to near-therapeutic levels in potentiating the action of rocuronium.

Conclusions

Bupivacaine, clindamycin, and gentamicin blocked NM conduction, and when all three drugs were applied together, they augmented rocuronium-induced NM block at their near-therapeutic concentrations. Clinicians should be aware of the cooperability in NM block between drugs that interrupt NM conduction.

At therapeutic concentration bupivacaine causes neuromuscular blockade and enhances rocuronium-induced blockade

BACKGROUND

Partially paralyzed patients may be placed in the risk of pharyngeal dysfunction. Bupivacaine acts as acetylcholine receptor ion channel blocker and may synergistically interact with rocuronium to augment NM blockade. Thus, this study aims to elucidate whether or not, at a therapeutic concentration, bupivacaine by itself may cause NM blockade and reduce an effective concentration of rocuronium.

METHODS

Twenty-two left phrenic nerve-hemidiaphragms (Male SD rats, 150-250 g) were hung in Krebs solution. Three consecutive ST, 0.1 Hz and one TT, 50 Hz for 1.9 s were obtained before drug application and at each new drug concentration. A concentration of bupivacaine in Krebs solution (n = 5) was cumulatively increased by way of 0.01, 0.1, 1, (1, 2, 3, 4, 5, 6, 7) × 10 µM. In a Krebs solution, pre-treated with bupivacaine 0 (n = 5), 0.1 (n = 5), 1.0 (n = 5), 10 (n = 2) µM, and then concentrations of rocuronium were cumulatively increased by way of 1, 3, 5, 7, 9, 12, 14, 16, 18, 20 µM. EC for each experiment were determined by a probit. The EC(50)'s of rocuronium were compared using a Student's t-test with Bonferroni's correction. Differences were considered significant when P < 0.05.

RESULTS

The potency of bupivacaine for normalized TF was 11.4 (± 1.1) µM. Below 30 µM of bupivacaine, the single twitch potentiation sustained despite the development of tetanic fade and partial inhibition of PTT. Bupivacaine significantly facilitated the NM blockade induced by rocuronium.

CONCLUSIONS

Clinicians should be aware that bupivacaine by itself at its therapeutic concentration inhibit NM conduction and enhances rocuronium-induced muscle relaxation.

Intravenous lidocaine has no impact on rocuronium-induced neuromuscular block. Randomised study

BACKGROUND

Intravenous lidocaine is increasingly used in surgical patients. As it has neuromuscular blocking effects, we tested the impact of an intravenous lidocaine infusion on the time course of a rocuronium-induced neuromuscular block.

METHODS

Fifty-two adults undergoing surgery were randomly allocated to intravenous lidocaine 1.5 mg/kg followed by a continuous infusion of 2 mg/kg/h or physiological saline (control) throughout surgery. Anaesthesia was induced and maintained with a target-controlled propofol infusion and sufentanil. After loss of consciousness, rocuronium 0.6 mg/kg was given. Neuromuscular transmission was measured using train-of-four (TOF)-watch SX (Organon, Swords Co., Dublin, Ireland) acceleromyography.

RESULTS

Onset time (to 95% depression of first twitch) was on average 113.9 s (standard deviation 35.3) with lidocaine and 119.5 s (44.9) with saline (P = 0.618). Total recovery time (TOF ratio 0.9) was on average 58.1 min (15.1) with lidocaine and 54.3 min (16.9) with saline (P = 0.394). Clinical duration (until first twitch has recovered to 25%) was on average 33.3 min (7.2) with lidocaine and 30.6 min (8.1) with saline (P = 0.21). Recovery index (time between 25% and 75% recovery of the first twitch) was on average 11.5 min (5.0) with lidocaine and 10.6 min (4.1) with saline (P = 0.458). Recovery time (between 25% recovery of the first twitch and TOF ratio 0.9) was on average 24.8 min (9.3) with lidocaine and 23.2 min (9.2) with saline (P = 0.541).

CONCLUSION

A continuous intravenous infusion of lidocaine has no impact on the time course of the neuromuscular blockade induced by a standard intubation dose of rocuronium.

The influence of lidocaine and racemic bupivacaine on neuromuscular blockade produced by rocuronium: a study in rat phrenic nerve-diaphragm preparation

PURPOSE: To evaluate in vitro lidocaine and racemic bupivacaine effects in neuromuscular transmission and in neuromuscular blockade produced by rocuronium. METHODS: Rats were distributed in 5 groups (n = 5) in agreement with the studied drugs: lidocaine, racemic bupivacaine, rocuronium, separately (Groups I, II, III); rocuronium in preparations exposed to local anesthetics (Groups IV, V). The concentrations used were: 20 µg/mL, 5 µg/mL and 4 µg/mL, for lidocaine, bupivacaine and rocuronium, respectively. It was evaluated: 1) amplitude of diaphragm muscle response to indirect stimulation, before and 60 minutes after separately addition of lidocaine, racemic bupivacaine and rocuronium and the association of local anesthetics - rocuronium; 2) membrane potentials (MP) and miniature end-plate potentials (MEPP). RESULTS: Lidocaine and bupivacaine separately didn't alter the amplitude of muscle response and MP. In preparations previously exposed to lidocaine and racemic bupivacaine, the rocuronium blockade was significantly larger (90.10 ± 9.15% and 100%, respectively), in relation to the produced by rocuronium separately (73.12 ± 9.89%). Lidocaine caused an increase in the frequency of MEPP, being followed by blockade; racemic bupivacaine produced decrease being followed by blockade. CONCLUSIONS: Local anesthetics potentiated the blockade caused by rocuronium. The alterations of MEPP identify presynaptic action.

Epidurally administered mepivacaine delays recovery of train-of-four ratio from vecuronium-induced neuromuscular block

BACKGROUND

The aim of this study was to examine the efficacy of epidurally administered mepivacaine on recovery from vecuronium-induced neuromuscular block.

METHODS

Eighty patients were randomly assigned to one of two study groups. They were either given epidurally a bolus of 0.15 ml kg(-1) of mepivacaine 2%, followed by repetitive injections of 0.1 ml kg(-1) h(-1) throughout the study, or were not given epidurally. General anaesthesia was induced and maintained with fentanyl, propofol and nitrous oxide. Neuromuscular block was induced with vecuronium 0.1 mg kg(-1) and monitored using acceleromyographic train-of-four (TOF) at the adductor pollicis. Patients in each treatment group were randomized to receive neostigmine 0.04 mg kg(-1) at 25% recovery of the first twitch of TOF or to recover spontaneously to a TOF ratio of 0.9. The effect of epidural mepivacaine on speed of spontaneous and facilitated recovery of neuromuscular function was evaluated.

RESULTS

The time from administration of vecuronium to spontaneous recovery to a TOF ratio of 0.9 was significantly longer in the epidural mepivacaine group [105.4 (14.2) min] as compared with the control group [78.5 (9.1) min, P < 0.01]. Neostigmine administered at 25% of control in T1 shortened recovery from neuromuscular block, however the time required for facilitated recovery to a TOF ratio of 0.9 in the epidural group was significantly longer than that in the control group [7.6 (1.6) min vs 5.8 (2.1) min, P < 0.01].

CONCLUSIONS

In clinical anaesthesia, it should be recognized that epidurally administered mepivacaine delays considerably the TOF recovery from neuromuscular block.