The neuromuscular effects of sevoflurane and isoflurane alone and in combination with vecuronium or atracurium in the rat

Effect of neuromuscular block on surgical conditions during laparoscopic surgery in neonates and small infants: A randomised controlled trial

BACKGROUND

Neuromuscular block (NMB) is routinely used in paediatric and adult anaesthesia to facilitate endotracheal intubation and optimise surgical conditions. However, there are limited data regarding NMB and optimising the conditions for laparoscopic surgery in neonates and small infants.

OBJECTIVE

The goal of this study was to determine the effect of NMB on the conditions for laparoscopic surgery in neonates and small infants.

DESIGN

A randomised controlled trial.

SETTING

Single-centre Children's Hospital, conducted from November 2021 to December 2022.

PATIENTS

One hundred and two ASA I-II neonates and small infants aged up to 60 weeks postmenstrual age who were scheduled to undergo an elective laparoscopic Ladd's procedure were included in the study.

INTERVENTIONS

Patients were randomised into three groups: no NMB group, shallow NMB group and moderate NMB group. Each group was given different doses of rocuronium to achieve the target depth of NMB.

MAIN OUTCOME MEASURES

The primary outcome was the quality of the surgical conditions evaluated with the Leiden-Surgical Rating Scale (L-SRS) by a blinded surgeon. Secondary outcomes included tracheal intubating conditions and adverse events.

RESULTS

The percentage of L-SRS scores of 4 or 5 was similar among the three groups at all the assessment times ( P  > 0.05 for each time interval). The distribution of L-SRS scores was also similar among the three groups. There were no significant differences in operating condition scores between the groups at any time interval ( P  > 0.05 for each time interval). The incidence of adverse events during anaesthesia induction was significantly higher in the no NMB group (51.4%) than in the other two groups (13.6% and 14.7%) (adjusted P  = 0.012 and adjusted P  = 0.003). In particular, clinically unacceptable intubation conditions occurred in 12 patients (34.3%) in the no NMB group, significantly more than in the shallow NMB group (6.1%, adjusted P  = 0.012) and moderate NMB group (2.9%, adjusted P  = 0.003). There was no statistically significant difference in the incidence of adverse events in the PACU among the three groups ( P  = 0.103).

CONCLUSIONS

The depth of NMB was not associated with superior surgical conditions during laparoscopic surgery, but it was associated with a reduction in adverse events during induction and maintenance of anaesthesia in neonates and small infants.

TRIAL REGISTRATION

Registered at www.chictr.org.cn (ChiCTR2100052296).

Quality of recovery in patients under low- or standard-pressure pneumoperitoneum. A randomised controlled trial

BACKGROUND

The use of low-pressure pneumoperitoneum seems to be capable of reducing complications such as post-operative pain. However, the quality of evidence supporting this conclusion is low. Both the lack of investigator blinding to both intra-abdominal pressure and to method of neuromuscular blockade represent key sources of bias. Hence, this prospective, randomised, and double-blind study aimed to compare the quality of recovery (Questionnaire QoR-40) of patients undergoing laparoscopic cholecystectomy under low-pressure and standard-pressure pneumoperitoneum. We tested the hypothesis that low pneumoperitoneum pressure enhances the quality of recovery following LC.

METHODS

Eighty patients who underwent elective laparoscopic cholecystectomy were randomly divided into two groups, a low-pressure (10 mm Hg) pneumoperitoneum group and a standard-pressure (14 mm Hg) pneumoperitoneum group. For all participants, the value of the insufflation pressure was kept hidden and only the nurse responsible for the operating room was aware of it. Deep neuromuscular blockade was induced for all cases [train-of-four (TOF) = 0; post-tetanic count (PTC) > 0]. The quality of recovery was assessed on the morning of first post-operative day.

RESULTS

No difference was found in either total score or in its different dimensions according to the QoR-40 questionnaire. The patients in the low-pressure pneumoperitoneum group experienced more pain during forced coughing measured at 4 hours (median difference [95% CI], 1 [0-2]; P = .030), 8 hours (1 [0-2]; P = .030) and 12 hours (0 [0-1] P = .025) after discharge from the post-anaesthesia care unit, when compared with those in the standard-pressure pneumoperitoneum group.

CONCLUSION

We thus conclude that the use of low-pressure pneumoperitoneum during elective laparoscopic cholecystectomy does not improve the quality of recovery.

Neuromuscular effects of sevoflurane in patients with myasthenia gravis

The current study evaluated the neuromuscular responses following administration of sevoflurane in 14 patients with myasthenia gravis (MG) (I-IIb in Osserman's classification) scheduled for thymectomy and in 11 control patients (ASA I-II) who underwent elective surgery. The electromyographic (EMG) response of the abductor digiti minimi was measured following train-of-four (TOF) stimulation of the ulnar nerve every 20 s. After induction of anesthesia with a combination of 3-4 mg·kg(-1) thiopental and 1-2 μg·kg(-1) fentanyl with 66% N2O and oxygen, an inspired concentration of 4% sevoflurane was administered via a face mask for 7 min. Anesthesia was maintained during surgery with 66% N2O in oxygen and with 1 minimum alveolar concentration (MAC) of end-tidal concentration of sevoflurane. The T1 (the amplitude of the first response) values decreased more profoundly in the MG patients than in the control patients at the end of surgery (P<0.05). Following administration of 4% sevoflurane for 7 min, the TOFR (the ratio of the fourth TOF to the first response) values revealed depressions greater than 10% of preinhalation values in 11 of 14 MG patients with a marked individual variation. This attenuated response was followed by a further depression of the TOFR values with increasing time of 1 MAC sevoflurane anesthesia. On the other hand, no notable changes were observed in patients with normal neuromuscular functions. The most significant factor that correlated with the depression of the TOFR values induced by 1 MAC sevoflurane was the anti-AchR antibody titers (P=0.029). Our results indicate that MG patients have an increased neuromuscular sensitivity to sevoflurane.

Reversal of profound rocuronium or vecuronium-induced neuromuscular block with sugammadex in isoflurane-anaesthetised dogs

This study evaluated the use of sugammadex for reversal of profound neuromuscular blockade induced with rocuronium or vecuronium in dogs. Anaesthesia was induced and maintained with isoflurane in oxygen in eight dogs on two occasions. Neuromuscular blockade was monitored using peroneal nerve stimulation and acceleromyography. Rocuronium 0.6 mg/kg or vecuronium 0.1mg/kg was administered intravenously (IV), followed 5 min later by sugammadex 8 mg/kg IV. Lag and onset time of rocuronium and vecuronium, lag time from sugammadex injection to recovery of first twitch response, recovery of T1/T0 to 25% and 75%, recovery index, and time to recovery of the train-of-four ratio (T4/T1) to 0.9 were recorded. Cardiovascular and respiratory parameters were also noted. Statistical analysis was performed using one-way ANOVA. Onset time for rocuronium (37 ± 18s; [mean ± SD]) was significantly shorter than for vecuronium (62 ± 15s) (P<0.04). No other significant differences were found between the two groups. After both rocuronium and vecuronium blockade, T4/T1 recovered to 0.9 in under 2 min after sugammadex (58.1 ± 67.8s and 98.1 ± 70.3s, respectively; P<0.32). Sugammadex can reverse profound neuromuscular blockade induced by vecuronium or rocuronium safely and rapidly in isoflurane-anaesthetised dogs.

The effect of sevoflurane and isoflurane on the neuromuscular block produced by vecuronium continuous infusion

Volatile anesthetics enhance the action of neuromuscular blockade to various degrees, although the influence of sevoflurane on the neuromuscular block has not yet been characterized. The purpose of this investigation is to determine the vecuronium infusion rate requirement under sevoflurane anesthesia and to compare it to that of isoflurane anesthesia. Twenty patients scheduled for otorhinolaryngologic surgery were randomly assigned to receive either sevoflurane (SEV) or isoflurane (ISO) at 1 minimum alveolar anesthetic concentration (MAC) (1.7% and 1.2%, respectively) in combination with 67% nitrous oxide. Anesthesia was induced with 5 mg/kg thiopental and muscle relaxation was obtained by a bolus of vecuronium infusion to achieve 90% muscle relaxation. The plasma concentrations of vecuronium (CVEC) and 3-desacetylvecuronium (CDES) at steady state were measured with a gas chromatographic assay. There was no difference between SEV and ISO in the following variables: the vecuronium infusion rate requirements to achieve 90% muscle relaxation (0.42 +/- 0.11 [SEV] vs 0.40 +/- 0.10 [ISO] microgram-kg-1.min-1), CVEC (144.4 +/- 38.1 [SEV] vs 149.7 +/- 69.2 [ISO] ng/mL), CDES (57.2 +/- 20.3 [SEV] vs 65.3 +/- 26.1 [ISO], ng/mL), and plasma vecuronium clearance (2.85 +/- 0.86 [SEV] vs 3.19 +/- 1.24 [ISO] mL.kg-1.min-1). This study indicates that SEV at 1 MAC requires a vecuronium infusion rate similar to that of ISO at 1 MAC to achieve 90% muscle relaxation.