Influence of Transverse Abdominis Plane Block on Intraoperative Diaphragmatic and Respiratory Functions in Patients Receiving Laparoscopic Colorectal Surgery

Background

The positive roles of deep muscle relaxation in abdominal surgeries and transversus abdominis plane block (TAPB) in the postoperative analgesia. This study aimed to discuss the effects of TAPB on abdominal muscle relaxation, the intraoperative diaphragmatic, and the respiratory functions.

Methods

The patients were randomly divided into the TAPB group who received single-shot TAPB bilaterally (n=30), and the control group who did not receive TAPB (n=30). Both groups keep the same steps for other procedures in the surgeries and anesthesia. Four time points for monitoring were defined: The moment when pneumoperitoneum pressure stabilized following endotracheal intubation and anesthetic induction (T0), appearance of the first incisure in the pressure-volume (P-V) loop (T1), appearance of the second incisure in the P-V loop (T2), and the moment with single stimulation (SS) =20% (T3). Primary observation parameters were SS1 measured by muscle relaxation monitoring at T1, and SS2 at T2. Secondary observation parameters included surgeon's satisfaction with surgical field and respiratory dynamics at the four time points.

Results

The two groups were comparable in age, gender, BMI, ASA grade, and operation time. The TAPB group had a dramatic reduction in the total dose of intraoperative sufentanil (0.73±0.21 ug/kg) compared with the control group (0.87±0.18 ug/kg) (P=0.023); Other use of drug did not differ between the two groups. The two groups did not differ significantly in SS at either T1 (SS1) or T2 (SS2). In either group, surgeon's satisfaction with surgical field at T1 and T2 decreased dramatically compared with T0 and T3 (all P<0.05). At each time point, the respiratory dynamics and the surgeon's satisfaction with surgical field did not differ significantly between the two groups.

Conclusion

TAPB reduced the use of intraoperative analgesics without altering the degree of abdominal relaxation, or affecting surgeon's satisfaction with surgical field in the patients receiving laparoscopic colorectal surgery.

[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).

Use of neuromuscular blockers and neostigmine for general anesthesia and its association with neuraxial blockade: A retrospective study

This research aimed to assess the use of neuromuscular blockers (NMB) and its reversal, associated or not with neuraxial blockade, after general anesthesia.This retrospective study analyzed 1295 patients that underwent surgery with general anesthesia at Prof. Dr. José Aristodemo Pinotti Hospital in 2013. The study included patients aged >1 year, with complete, readable medical charts and anesthetic records.Rocuronium (ROC) was the most used NMB (96.7%), with an initial dose of 0.60 (0.52-0.74) mg/kg and total dose of 0.38 (0.27-0.53) mg/kg/h. In 24.3% of the cases, neuraxial blockade was associated with a significantly longer anesthesia (P < .001) than in cases without neuraxial block, regardless of technique (total intravenous (TIV) vs intravenous and inhalational (IV+IN)). In 71.9% of the cases, a single dose of NMB was used. Patients under TIV general anesthesia associated with neuraxial blockade had a lower total dose of ROC (mg/kg/h) in comparison with TIV GA alone (0.30 (0.23-0.39) and 0.42 (0.30-0.56) mg/kg/h, respectively, P < .001). The same was observed for patients under IV+IN GA (0.32 (0.23-0.41) and 0.43 (0.31-0.56) mg/kg/h, respectively, P < .001). The duration of anesthesia was longer according to increasing number of additional NMB doses (P < .001). Dose of neostigmine was 2.00 (2.00-2.00) mg or 29.41 (25.31-33.89) μg/kg. The interval between neostigmine and extubation was >30 minutes in 10.9% of cases.The most widely used NMB was ROC. Neuroaxial blockade (spinal or epidural) was significantly associated with reduced total dose of ROC (mg/kg/h) during general anesthesia, even in the absence of neuromuscular monitoring and regardless of general anesthetic technique chosen. In most cases, neostigmine was used to reverse neuromuscular block. The prolonged interval between neostigmine and extubation (>30 minutes) was neither associated with total doses of ROC or neostigmine, nor with the time of NMB administration. This study corroborates the important role of quantitative neuromuscular monitors and demonstrates that neuraxial blockade is associated with reduced total ROC dose. Further studies are needed to evaluate the possible role of neuraxial blockade in reducing the incidence of postoperative residual curarization.

Association between levobupivacaine and pancuronium. Interference in neuromuscular transmission and blockade in rats

PURPOSE

To evaluate the effects of levobupivacaine on neuromuscular transmission and neuromuscular blockade produced by pancuronium in vitro.

METHODS

Thirty rats were distributed into groups (n = 5) according to the drug used alone or in combination: Group I - levobupivacaine (5 µg.mL-1); Group II - pancuronium (2 µg.mL-1); Group III - pancuronium (2 µg.mL-1) + levobupivacaine (5µg.mL-1). The following parameters were evaluated: 1) amplitude of diaphragmatic response to indirect stimulation, before and 60 minutes after the addition of levobupivacaine and pancuronium alone, and after the addition of levobupivacaine combined with pancuronium; 2) membrane potentials (MP) and miniature endplate potentials (MEPP).

RESULTS

Levobupivacaine alone did not alter the amplitude of muscle response and MP. In preparations previoulsy exposed to levobupivacaine, the block with pancuronium was significantly denser (90.2 ± 15.2%), showing a significant difference (p=0.031) in comparison to the block produced by pancuronium alone (48.9% ± 9.8%). There was a decrease in the frequency and amplitude of MEPPs.

CONCLUSION

Levobupivacaine potentiated the neuromuscular blockade produced by pancuronium, confirming a presynaptic action by a decrease in miniature endplate potentials.

Effect of 50% enantiomeric excess bupivacaine mixture combined with pancuronium on neuromuscular transmission in rat phrenic nerve-diaphragm preparation; a pilot study

BACKGROUND AND AIMS

Local anaesthetics are drugs that are widely used in clinical practice. However, the effects of these drugs on the neuromuscular junction and their influence on the blockade produced by non-depolarising neuromuscular blocking drugs are still under investigation. The aim of this study was to evaluate, in vitro, the influence of a 50% enantiomeric excess bupivacaine mixture on neuromuscular transmission and neuromuscular block produced by pancuronium.

METHODS

Rats were distributed into three groups (n = 5) according to the drug studied namely, 50% enantiomeric excess bupivacaine mixture (5 μg/mL); pancuronium (2 μg/mL); 50% enantiomeric excess bupivacaine mixture + pancuronium. The following parameters were evaluated: (1) Effects of a 50% enantiomeric excess bupivacaine mixture on membrane potential (MP) and miniature endplate potentials (MEPPs); (2) amplitude of diaphragmatic response before and 60 min after the addition of a 50% enantiomeric excess bupivacaine mixture; the degree of neuromuscular block with pancuronium and pancuronium combined with a 50% enantiomeric excess bupivacaine mixture.

RESULTS

A 50% enantiomeric excess bupivacaine mixture did not alter the amplitude of muscle response (MP) but decreased the frequency and amplitude of MEPP. The block produced by pancuronium was potentiated by a 50% enantiomeric excess bupivacaine mixture.

CONCLUSION

A 50% enantiomeric excess bupivacaine mixture used alone did not affect neuromuscular transmission, but potentiated the neuromuscular block produced by pancuronium. No action was shown on the muscle fibre, and alterations on MEPPs demonstrated a presynaptic action.

[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.

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.