Low-dose rocuronium improves conditions for tracheal intubation after induction of anaesthesia with propofol and alfentanil

The optimal induction dose of ciprofol combined with low-dose rocuronium in children undergoing daytime adenotonsillectomy

Adenotonsillectomy is the most common daytime surgery performed on children. Anesthesiologists must select the optimal combination of drugs to ensure effective anesthesia effect and prompt recovery in children. The optimal induction dose of ciprofol in children is unclear. In this study, we aim to investigate the effect of different doses of ciprofol on anesthesia induction in children undergoing daytime adenotonsillectomy and provide a reference for clinical use. 144 children aged 3-12 years, ASA I-II, undergoing daytime adenotonsillectomy, were included in this clinical trial. The children were randomly divided into three groups and given 0.4 mg/kg (C4), 0.6 mg/kg (C6), or 0.8 mg/kg (C8) of ciprofol for anesthesia induction. The primary outcome was intubation conditions. Vital signs and injection pain were also recorded. The rates of unacceptable intubation conditions were 30.6%, 8.7%, and 8.2% in the C4, C6, and C8 groups (P value < 0.0167). The overall incidence of reported injection pain was 3.5%. The heart rate and mean arterial pressure did not differ between the groups at the same time points. We found that combining 0.6 mg/kg of ciprofol with low-dose rocuronium could provide optimal intubation conditions in pediatric daytime adenotonsillectomy patients. This combination resulted in stable circulation and BIS values. This study is registered at the Chinese Clinical Trial Registry (Registration number: ChiCTR2200063144, Date of Registration: 31/08/2022).

Rocuronium with sugammadex as a rescue reversal agent to solve conflicting recommendations for thyroid or parathyroid surgery. A prospective study

INTRODUCTION

For thyroid or parathyroid surgery, there is a challenge to select a muscle relaxant agent allowing a good quality for tracheal intubation without any residual effect at the time of intraoperative neural monitoring.

PATIENTS AND METHODS

In this monocentric study, non-morbidly obese adult patients without risk factors for difficult tracheal intubation who underwent thyroid or parathyroid surgery with intraoperative neural monitoring were prospectively included. After rocuronium injection (0.5 mg.kg^-1) during propofol-sufentanil induction, intubation conditions were evaluated using the Copenhagen score. The surgeon positioned the electrodes NIM® and tested the vagal nerve before recurrent nerve dissection. The signal was considered positive when the wave amplitude exceeded 100 μV. If not, sugammadex (2 mg.kg^-1) was administered. The dissection began when the signal was positive.

RESULTS

From January 2022 to June 2022, 48 out of 50 patients, 39 (81%) female, met inclusion criteria and were prospectively recruited in the study (two patients had predictable difficult intubation criteria). Intubation conditions were clinically acceptable for 46/48 (96%) of patients. The time delay from rocuronium injection to vagal stimulation was 43 min (mean) +/- 11 (SD). The vagal stimulation was positive in 45 patients (94%). In the 3 remaining patients, sugammadex successfully reversed residual curarization and allowed positive vagal stimulation.

DISCUSSION

This prospective study shows that the use of 0.5 mg.kg^-1 rocuronium with sugammadex as a rescue reversal agent allows good quality and safety for intubation conditions and intraoperative neural monitoring in patients scheduled for thyroid or parathyroid surgery.

Peri-operative management of neuromuscular blockade: A guideline from the European Society of Anaesthesiology and Intensive Care

Recent data indicated a high incidence of inappropriate management of neuromuscular block, with a high rate of residual paralysis and relaxant-associated postoperative complications. These data are alarming in that the available neuromuscular monitoring, as well as myorelaxants and their antagonists basically allow well tolerated management of neuromuscular blockade. In this first European Society of Anaesthesiology and Intensive Care (ESAIC) guideline on peri-operative management of neuromuscular block, we aim to present aggregated and evidence-based recommendations to assist clinicians provide best medical care and ensure patient safety. We identified three main clinical questions: Are myorelaxants necessary to facilitate tracheal intubation in adults? Does the intensity of neuromuscular blockade influence a patient's outcome in abdominal surgery? What are the strategies for the diagnosis and treatment of residual paralysis? On the basis of this, PICO (patient, intervention, comparator, outcome) questions were derived that guided a structured literature search. A stepwise approach was used to reduce the number of trials of the initial research ( n  = 24 000) to the finally relevant clinical studies ( n  = 88). GRADE methodology (Grading of Recommendations, Assessment, Development and Evaluation) was used for formulating the recommendations based on the findings of the included studies in conjunction with their methodological quality. A two-step Delphi process was used to determine the agreement of the panel members with the recommendations: R1 We recommend using a muscle relaxant to facilitate tracheal intubation (1A). R2 We recommend the use of muscle relaxants to reduce pharyngeal and/or laryngeal injury following endotracheal intubation (1C). R3 We recommend the use of a fast-acting muscle relaxant for rapid sequence induction intubation (RSII) such as succinylcholine 1 mg kg -1 or rocuronium 0.9 to 1.2 mg kg -1 (1B). R4 We recommend deepening neuromuscular blockade if surgical conditions need to be improved (1B). R5 There is insufficient evidence to recommend deep neuromuscular blockade in general to reduce postoperative pain or decrease the incidence of peri-operative complications. (2C). R6 We recommend the use of ulnar nerve stimulation and quantitative neuromuscular monitoring at the adductor pollicis muscle to exclude residual paralysis (1B). R7 We recommend using sugammadex to antagonise deep, moderate and shallow neuromuscular blockade induced by aminosteroidal agents (rocuronium, vecuronium) (1A). R8 We recommend advanced spontaneous recovery (i.e. TOF ratio >0.2) before starting neostigmine-based reversal and to continue quantitative monitoring of neuromuscular blockade until a TOF ratio of more than 0.9 has been attained. (1C).

Anesthetic Technique and Functional Outcomes in Modified Montgomery Thyroplasty

BACKGROUND

Montgomery thyroplasty type I is a surgical technique indicated in vocal cord paralysis which consists of the paralyzed cord medialization, improving the voice quality. The objective of the study is to describe in detail the anesthetic method to obtain optimal post-medialization voice results.

METHODOLOGY

Retrospective case series study including patients who underwent medialization thyroplasty using the modified Montgomery technique at the General University Hospital of Valencia between 2011 and 2021. The anesthetic technique consisted of general anesthesia with neuromuscular relaxation and a laryngeal mask. Pre- and post-surgical vocal functional data of maximum phonation times (MPT), G score, and Voice Handicap Index-30 (VHI-30) were evaluated.

RESULTS

All the patients presented an improvement in voice results, increasing MPT after surgery and a decrease in VHI-30 and G score postoperatively, with statistically significant differences between the pre- and post-surgical results (p-value < 0.05). There were no complications related to anesthesia or surgery.

CONCLUSIONS

The use of general anesthesia with muscle relaxation in modified Montgomery thyroplasty may be a good option to consider. The use of a laryngeal mask for ventilation combined with a fiberoptic check allows direct visualization of the vocal cords intraoperatively, providing good functional voice results.

Personalized Medicine for Classical Anesthesia Drugs and Cancer Progression

In this review, we aim to discuss the use and effect of five different drugs used in the induction of anesthesia in cancer patients. Propofol, fentanyl, rocuronium, sugammadex, and dexamethasone are commonly used to induce anesthesia and prevent pain during surgery. Currently, the mechanisms of these drugs to induce the state of anesthesia are not yet fully understood, despite their use being considered safe. An association between anesthetic agents and cancer progression has been determined; therefore, it is essential to recognize the effects of all agents during cancer treatment and to evaluate whether the treatment provided to the patients could be more precise. We also highlight the use of in silico tools to review drug interaction effects and safety, as well as the efficacy of the treatment used according to different subgroups of patients.

Does the Use of Rocuronium-Sugammadex Instead of Succinylcholine in Electroconvulsive Therapy Affect Seizure Duration?

OBJECTIVE

We compared retrospectively the seizure variables of electroconvulsive therapy (ECT) patients after administration of rocuronium-sugammadex or succinylcholine as a muscle relaxant with propofol anesthesia.

METHODS

The sample comprised 134 ECT patients. The mean age was 33.6±10.48 years. Anesthesia induction was provided with propofol one mg kg-intravenously (IV) followed by succinylcholine 0.5 mg kg-1 IV (n=68) (Group S) or rocuronium 0.3 mg kg-1 IV (n=66) (Group R). For patients who were given rocuronium, reversal of the residual neuromuscular block was accomplished with sugammadex (1.5 mg kg-1 IV). First session seizure variables were compared between the two groups. We also presented the clinical outcome with Clinical Global Impression-Improvement (CGI-I) and overall adverse effects.

RESULTS

EEG seizure durations in Group R (55.09±36.11 s) and Group S (47.00±26.33 s) were comparable and were not significantly different (p=0.432). The clinical efficacy of ECT measured by CGI-I in both groups was comparable (p=0.075). There were no major complications or death during or after ECT.

CONCLUSION

The results of this study show that the use of rocuronium-sugammadex as a neuromuscular blocker instead of succinylcholine during ECT with propofol anesthesia produces similar results in terms of seizure variables and clinical outcomes.

Rocuronium 0.3 mg/kg or 0.9 mg/kg comparing onset time, duration of action and intubating conditions in patients 80 years and older. A randomized study

BACKGROUND

Limited data exist about the optimal dose of rocuronium for intubation in elderly patients. We hypothesized that rocuronium 0.9 mg kg^-1 would lead to a shorter onset time than 0.3 mg kg^-1 in patients above 80 years.

METHODS

Thirty-four patients were randomized to either rocuronium 0.3 mg kg^-1 or 0.9 mg kg^-1 . The primary outcome was onset time defined as time to train-of-four (TOF) count of 0. Other outcomes included duration of action (time to TOF ratio > 0.9), proportion of excellent intubating conditions using the Fuchs-Buder scale and tracheal intubating conditions using the Intubating Difficulty Scale (IDS).

RESULTS

Rocuronium 0.9 mg kg^-1 resulted in shorter onset time compared to rocuronium 0.3 mg kg^-1 ; 108 sec (SD 40) vs. 228 sec (SD 140) (difference: 119 seconds (95% CI: 41-196), P=0.005)), respectively. However, in 66% of the patients receiving rocuronium 0.3 mg kg^-1 a TOF count of 0 was not obtained. Duration of action was longer after rocuronium 0.9 mg kg^-1 : 118 minutes (SD 43) vs. 46 minutes (SD 13) (difference: 72 minutes (95% CI: 49-95) P<0.0001)), and a greater proportion of excellent intubating conditions (Fuchs-Buder) was obtained; 11/16 (69%) vs 4/18 (22%) (P=0.006). No difference was found regarding IDS score.

CONCLUSION

Rocuronium 0.9 mg kg^-1 resulted in a shorter onset time compared to rocuronium 0.3 mg kg^-1 in patients above 80 years of age. In 66% of the patients receiving rocuronium 0.3 mg kg^-1 a TOF count of 0 was not obtained.

Does Rocuroinum Dose Adjusted Due to Lean Body Weight Provide Adequate Intubation Conditions?: A Prospective Observational Study

METHODS

This is a prospective, observational study. Patients between the ages of 18 and 65 with BMI of 18.5-34.9, who are expected to be under general anesthesia for less than 6 hours, were divided into 3 groups according to their BMI (Group 1 BMI = 18.5-24.9, Group 2 BMI = 25-29.9, Group 3 BMI = 30-34.9). These groups were randomly divided into 2 subgroups: Groups LBW; 1 LBW, 2 LBW, and 3 LBW were given rocuronium intubation dosages based on their LBW while control groups; 1K, 2K, and 3K were given 0.6 mg/kg rocuronium according to their total body weight. The data on the duration of action of rocuronium and its effects on the endotracheal intubation conditions were evaluated.

RESULTS

In Group 1, T1 time was found to be significantly longer (p=0.001). Intubation score and the use of additional rocuronium dose were found to be significantly higher in Group 1 LBW than in Group 1K (p=0.001). In Group 1, an additional rocuronium dose was needed to achieve optimal intubation conditions for subgroup 1 LBW. Rocuronium duration of action was found to be significantly longer in control groups 2 and 3, that received TBW-based dosage.

CONCLUSION

In adult patients with a BMI of 18.5 and 24.9 BMI, we report optimal intubation conditions with the LBW-adjusted rocuronium dosage. This trial is registered with NCT05476952.

Cautionary findings for motor evoked potential monitoring in intracranial aneurysm surgery after a single administration of rocuronium to facilitate tracheal intubation

Administration of rocuronium to facilitate intubation has traditionally been regarded as acceptable for intraoperative motor evoked potential (MEP) monitoring because of sufficiently rapid spontaneous neuromuscular blockade recovery. We hypothesized that residual neuromuscular blockade, in an amount that could hinder optimal neuromonitoring in patients undergoing intracranial aneurysm clipping, was still present at dural opening. We sought to identify how often this was occurring and to identify factors which may contribute to prolonged blockade. Records of 97 patients were retrospectively analyzed. Rocuronium was administered to facilitate intubation with no additional neuromuscular blockade given. Prolonged spontaneous recovery time to a train-of-four (TOF) ratio of 0.75 after rocuronium administration was defined as 120 min, which was approximately when dural opening and the setting of baseline MEPs were occurring. Logistic regression analysis was used to identify factors related to prolonged spontaneous recovery time. Prolonged spontaneous recovery time to a TOF ratio of 0.75 was observed in 44.3% of patients. Multivariable analysis showed that only the dosage of rocuronium based on ideal body weight had a positive correlation with prolonged spontaneous recovery time (P = 0.01). There was no significant association between dosage of rocuronium based on total body weight, age, sex, or body temperature and prolonged recovery time. This study demonstrates that the duration of relaxation for MEP monitoring purposes is well-beyond the routinely recognized clinical duration of rocuronium. Residual neuromuscular blockade could result in lower amplitude MEP signals and/or lead to higher required MEP stimulus intensities which can both compromise monitoring sensitivity.

Guidelines on muscle relaxants and reversal in anaesthesia

OBJECTIVES

To provide an update to the 1999 French guidelines on "Muscle relaxants and reversal in anaesthesia", a consensus committee of sixteen experts was convened. A formal policy of declaration and monitoring of conflicts of interest (COI) was developed at the outset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e. pharmaceutical, medical devices). The authors were required to follow the rules of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE®) system to assess the quality of the evidence on which the recommendations were based. The potential drawbacks of making strong recommendations based on low-quality evidence were stressed. Few of the recommendations remained ungraded.

METHODS

The panel focused on eight questions: (1) In the absence of difficult mask ventilation criteria, is it necessary to check the possibility of ventilation via a facemask before muscle relaxant injection? Is it necessary to use muscle relaxants to facilitate facemask ventilation? (2) Is the use of muscle relaxants necessary to facilitate tracheal intubation? (3) Is the use of muscle relaxants necessary to facilitate the insertion of a supraglottic device and management of related complications? (4) Is it necessary to monitor neuromuscular blockade for airway management? (5) Is the use of muscle relaxants necessary to facilitate interventional procedures, and if so, which procedures? (6) Is intraoperative monitoring of neuromuscular blockade necessary? (7) What are the strategies for preventing and treating residual neuromuscular blockade? (8) What are the indications and precautions for use of both muscle relaxants and reversal agents in special populations (e.g. electroconvulsive therapy, obese patients, children, neuromuscular diseases, renal/hepatic failure, elderly patients)? All questions were formulated using the Population, Intervention, Comparison and Outcome (PICO) model for clinical questions and evidence profiles were generated. The results of the literature analysis and the recommendations were then assessed using the GRADE® system.

RESULTS

The summaries prepared by the SFAR Guideline panel resulted in thirty-one recommendations on muscle relaxants and reversal agents in anaesthesia. Of these recommendations, eleven have a high level of evidence (GRADE 1±) while twenty have a low level of evidence (GRADE 2±). No recommendations could be provided using the GRADE® system for five of the questions, and for two of these questions expert opinions were given. After two rounds of discussion and an amendment, a strong agreement was reached for all the recommendations.

CONCLUSION

Substantial agreement exists among experts regarding many strong recommendations for the improvement of practice concerning the use of muscle relaxants and reversal agents during anaesthesia. In particular, the French Society of Anaesthesia and Intensive Care (SFAR) recommends the use of a device to monitor neuromuscular blockade throughout anaesthesia.

Subparalyzing Doses of Rocuronium Reduce Muscular Endurance without Detectable Effect on Single Twitch Height in Awake Subjects

PURPOSE

To test the hypothesis that a low-dose rocuronium acts mainly by means of reducing muscular endurance rather than by reducing momentary force.

METHODS

In a randomized placebo-controlled double-blinded study, eight healthy volunteers were studied in two sets of experiments. In the first set, the subjects made a sustained maximum effort with the dominant hand for 80 seconds while squeezing an electronic handgrip dynamometer at three minutes after intravenous administration of placebo, 0.04 or 0.08 mg/kg rocuronium. Handgrip force at initiation of testing (maximum handgrip force) and after 60 seconds was evaluated. In the second set, the ulnar nerve of the subjects was electrically stimulated every tenth second for at least 10 and a maximum of 30 minutes following the administration of placebo and 0.08 mg/kg rocuronium. Single twitch height of the adductor pollicis muscle was recorded.

RESULTS

There was no significant difference in the effect on maximum handgrip force at time 0 between the three different doses of rocuronium. As compared with placebo, handgrip force after 0.08 mg/kg rocuronium was reduced to approximately a third at 60 seconds (214 N (120-278) vs. 69 (30-166); p=0.008), whereas only a slight reduction was seen after 0.04 mg/kg (187 (124-256); p=0.016). Based on these results, the sustained handgrip force after 0.2 mg/kg at 60 seconds was calculated to be 1.27% (95% CI [0.40, 4.03]) of the maximum force of placebo. No effect on single twitch height after 0.08 mg/kg rocuronium at four minutes after drug administration could be detected.

CONCLUSIONS

Subparalyzing doses of rocuronium show a distinct effect on muscular endurance as opposed to momentary force. The findings support the hypothesis that low doses of rocuronium act mainly by reducing muscular endurance, thereby facilitating, for example, tracheal intubation.

The effect of low-dose rocuronium on rapid tracheal intubation using a video laryngoscope: A randomized double blind controlled study

BACKGROUND

The aim of this study was to investigate the clinical effectiveness of rocuronium in low doses on conditions during rapid tracheal intubation using video laryngoscope.

METHODS

Ninety-eight patients undergoing otolaryngologic surgery were randomly divided into 2 groups: group L using 0.3 mg/kg of rocuronium intravenously (n = 49) and group C using 0.6 mg/kg of rocuronium (n = 49). Sixty seconds after rocuronium administration, tracheal intubation was performed using a video laryngoscope. The overall intubation condition was evaluated along with specific conditions, including laryngoscopy condition, vocal cord position, and intubation response. Intubation profiles, including Cormack-Lehane grade, 1st attempt success rate, and intubation time, were also evaluated.

RESULTS

Overall intubation conditions showed a significant difference between group L and group C (P = .003). Although the incidence of vigorous response after tracheal intubation was higher in group L than in group C (P = .022), laryngoscopy condition and vocal cord position were similar between the 2 groups (P = .145 and .070, respectively). Intubation profiles showed no differences between the 2 groups. The frequency and amount of additional rocuronium administration during surgery were also similar.

CONCLUSIONS

Low-dose rocuronium provided significantly worse overall intubation conditions compared to the conventional dose of rocuronium for rapid tracheal intubation. However, when using a video laryngoscope, it may provide clinically acceptable laryngeal muscle relaxation.

Avoidance versus use of neuromuscular blocking agents for improving conditions during tracheal intubation or direct laryngoscopy in adults and adolescents

BACKGROUND

Tracheal intubation during induction of general anaesthesia is a vital procedure performed to secure a patient's airway. Several studies have identified difficult tracheal intubation (DTI) or failed tracheal intubation as one of the major contributors to anaesthesia-related mortality and morbidity. Use of neuromuscular blocking agents (NMBA) to facilitate tracheal intubation is a widely accepted practice. However, because of adverse effects, NMBA may be undesirable. Cohort studies have indicated that avoiding NMBA is an independent risk factor for difficult and failed tracheal intubation. However, no systematic review of randomized trials has evaluated conditions for tracheal intubation, possible adverse effects, and postoperative discomfort.

OBJECTIVES

To evaluate the effects of avoiding neuromuscular blocking agents (NMBA) versus using NMBA on difficult tracheal intubation (DTI) for adults and adolescents allocated to tracheal intubation with direct laryngoscopy. To look at various outcomes, conduct subgroup and sensitivity analyses, examine the role of bias, and apply trial sequential analysis (TSA) to examine the level of available evidence for this intervention.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, BIOSIS, International Web of Science, LILACS, advanced Google, CINAHL, and the following trial registries: Current Controlled Trials; ClinicalTrials.gov; and www.centerwatch.com, up to January 2017. We checked the reference lists of included trials and reviews to look for unidentified trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared the effects of avoiding versus using NMBA in participants 14 years of age or older.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. We conducted random-effects and fixed-effect meta-analyses and calculated risk ratios (RRs) and their 95% confidence intervals (CIs). We used published data and data obtained by contacting trial authors. To minimize the risk of systematic error, we assessed the risk of bias of included trials. To reduce the risk of random errors caused by sparse data and repetitive updating of cumulative meta-analyses, we applied TSA.

MAIN RESULTS

We identified 34 RCTs with 3565 participants that met our inclusion criteria. All trials reported on conditions for tracheal intubation; seven trials with 846 participants described 'events of upper airway discomfort or injury', and 13 trials with 1308 participants reported on direct laryngoscopy. All trials used a parallel design. We identified 18 dose-finding studies that included more interventions or control groups or both. All trials except three included only American Society of Anesthesiologists (ASA) class I and II participants, 25 trials excluded participants with anticipated DTI, and obesity or overweight was an excluding factor in 13 studies. Eighteen trials used suxamethonium, and 18 trials used non-depolarizing NMBA.Trials with an overall low risk of bias reported significantly increased risk of DTI with no use of NMBA (random-effects model) (RR 13.27, 95% CI 8.19 to 21.49; P < 0.00001; 508 participants; four trials; number needed to treat for an additional harmful outcome (NNTH) = 1.9, I² = 0%, D² = 0%, GRADE = moderate). The TSA-adjusted CI for the RR was 1.85 to 95.04. Inclusion of all trials resulted in confirmation of results and of significantly increased risk of DTI when an NMBA was avoided (random-effects model) (RR 5.00, 95% CI 3.49 to 7.15; P < 0.00001; 3565 participants; 34 trials; NNTH = 6.3, I² = 70%, D² = 82%, GRADE = low). Again the cumulative z-curve crossed the TSA monitoring boundary, demonstrating harmful effects of avoiding NMBA on the proportion of DTI with minimal risk of random error. We categorized only one trial reporting on upper airway discomfort or injury as having overall low risk of bias. Inclusion of all trials revealed significant risk of upper airway discomfort or injury when an NMBA was avoided (random-effects model) (RR 1.37, 95% CI 1.09 to 1.74; P = 0.008; 846 participants; seven trials; NNTH = 9.1, I² = 13%, GRADE = moderate). The TSA-adjusted CI for the RR was 1.00 to 1.85. None of these trials reported mortality. In terms of our secondary outcome 'difficult laryngoscopy', we categorized only one trial as having overall low risk of bias. All trials avoiding NMBA were significantly associated with difficult laryngoscopy (random-effects model) (RR 2.54, 95% CI 1.53 to 4.21; P = 0.0003; 1308 participants; 13 trials; NNTH = 25.6, I² = 0%, D²= 0%, GRADE = low); however, TSA showed that only 6% of the information size required to detect or reject a 20% relative risk reduction (RRR) was accrued, and the trial sequential monitoring boundary was not crossed.

AUTHORS' CONCLUSIONS

This review supports that use of an NMBA may create the best conditions for tracheal intubation and may reduce the risk of upper airway discomfort or injury following tracheal intubation. Study results were characterized by indirectness, heterogeneity, and high or uncertain risk of bias concerning our primary outcome describing difficult tracheal intubation. Therefore, we categorized the GRADE classification of quality of evidence as moderate to low. In light of defined outcomes of individual included trials, our primary outcomes may not reflect a situation that many clinicians consider to be an actual difficult tracheal intubation by which the patient's life or health may be threatened.

Intubation conditions in young infants after propofol and remifentanil induction with and without low-dose rocuronium

BACKGROUND

Bolus injections of intravenous propofol and remifentanil can be used in the tracheal intubation of infants and children, but relatively large doses are needed. We hypothesised that addition of a small bolus of rocuronium would ensure good intubation conditions when modest propofol and remifentanil doses were used.

METHODS

Seventy infants between 3 weeks and 4 months of age were randomised to receive either placebo or rocuronium. Anaesthesia was induced with IV propofol, 3 (3-5) mg/kg [median (range)]. Rocuronium (0.2 mg/kg) or placebo was then injected, followed 15 s later by 2 μg/kg remifentanil. One anaesthetist attempted tracheal intubation 1 min after the rocuronium/placebo injection and used the 'Copenhagen scoring system' to assess intubation conditions. The neuromuscular effect of 0.2 mg/kg rocuronium was recorded in another eight, already intubated, infants using thumb accelerometry during train-of-four stimulation of the ulnar nerve.

RESULTS

Intubation conditions were classified as 'poor' in 14 of 34 (41%) patients given placebo and in 10 of 36 (28%) patients given rocuronium (P = 0.32). There were four failed first attempts at intubation in the placebo group and none in the rocuronium group (P = 0.051). Maximum neuromuscular depression occurred 4 (3-8) after injection of 0.2 mg/kg rocuronium.

CONCLUSIONS

Intubation conditions were poor in almost one third of the patients receiving propofol-remifentanil. Adding a low-dose rocuronium did not significantly improve intubation conditions.

Anesthesiologist's satisfaction using between cisatracurium and rocuronium for the intubation in the anesthesia induced by remifentanil and propofol

BACKGROUND

Although cisatracurium has many advantages in anesthetic practices, the best choice of a nondepolarizing neuromuscular blocking agent that can replace succinylcholine is rocuronium. However, it is reported that remifentanil with propofol might provide reliable intubating condition, even without a neuromuscular blocking agent; therefore, it might improve the intubating condition with cisatracurium. This study examined intubating conditions after administering rocuronium or cisatracurium in a rapid sequence induction with remifentanil-propofol.

METHODS

Fifty two ASA physical status 1 or 2 adult patients scheduled for an elective surgery were enrolled in a randomized double-blinded trial. Anesthesia was induced in all patients with propofol 2.0 mg/kg and remifentanil 0.5 µg/kg, administered over 60 seconds. Rocuronium 0.9 mg/kg (3 × ED(95), R group, n = 23) or cisatracurium 0.15 mg/kg (3 × ED(95), C group, n = 29) was administered after the induction sequence. Laryngoscopy was attempted when the anesthesiologist thought it was 90 seconds after drug administration and appropriate time for intubation. The examiner, another anesthesiologist, recorded the exact time to intubation and suppression of maximal T1 on TOF. The intubating condition was assessed by the first anesthesiologist, as excellent, good, poor or not possible.

RESULTS

The best time to laryngoscopy was predicted by measuring TOF and was found to be significantly longer in the C group (197 ± 53 s) than in the R group (102 ± 49 s) (P value < 0.05). However, time to larygoscopy, intubating condition during the laryngoscopy, and hemodynamic changes after intubation was similar in both groups.

CONCLUSIONS

Despite fundamentally slower onset time, cisatracurium can provide quite good intubating conditions, which were comparable to those achieved with equipotent doses of rocuronium, which is more expensive in anesthesia inducted with remifentanil and propofol.

Intubation time required for tracheal intubation with low-dose rocuronium in children with and without atropine

PURPOSE

The purpose of this study was to determine the intubation time needed to facilitate tracheal intubation (Time(EI)) with a low dose of rocuronium (0.3 mg/kg) during propofol induction, and to determine whether this time was reduced by the administration of atropine.

METHODS

Forty-six children, aged 3-10 years, were randomly assigned to receive either saline (control group) or atropine 10 μg/kg (atropine group). Anesthesia was induced with alfentanil 10 μg/kg, propofol 2.5 mg/kg, and rocuronium 0.3 mg/kg. Each Time(EI) at which tracheal intubation was attempted was predetermined according to the up-and-down method. The values of Time(EI) that provided excellent intubation conditions in 50 and 95 % of patients were defined as Time(EI)50 and Time(EI)95, respectively.

RESULTS

Time(EI)50 ± SD was 160 ± 26.2 and 150 ± 13.7 s in the control and atropine groups, respectively. Using isotonic regression, Time(EI)95 in the control and atropine groups was 199 s (95 % CI 198.8-200.7 s) and 171 s (95 % CI 171.3-172.1 s), respectively. Time(EI)95 was significantly higher in the control group than in the atropine group (P < 0.001). HR was significantly higher in the atropine group than in the control group during the study period.

CONCLUSIONS

This study demonstrated that the Time(EI)95 of a low dose of rocuronium (0.3 mg/kg) required for excellent tracheal intubation was 199 s during i.v. anesthesia induction using propofol and alfentanil in children. Also, i.v. atropine (10 μg/kg) before anesthesia induction was able to reduce Time(EI)95 by 28 s.

Comparison of intubating conditions following administration of low-dose rocuronium or succinylcholine in adults: A randomized double blind study

CONTEXT

Though rocuronium has a rapid onset of neuromuscular blockade like succinylcholine without the latter's adverse effects, its use is limited due to its prolonged action.

AIM

Aim was to evaluate whether reducing the intubating dose of rocuronium shortens its duration of action, yet provides clinically acceptable intubating conditions.

SETTINGS AND DESIGN

tt was a prospective, randomized, and double blind trial.

MATERIALS AND METHODS

100 American Society of Anaesthesiologists Physical Status (ASAPS) I or II patients aged between 18-65 years scheduled for elective surgery were randomly allotted one of the four rocuronium groups (rocuronium dose of 0.3 mg/kg intubated at 60 s or at 90 s, rocuronium 0.6 mg/kg intubated at 60 s or at 90 s) orsuccinylcholine group (succinylcholine 1.0 mg/kg intubated at 60 s) and intubating conditions were assessed with: Ease of laryngoscopy, vocal cord position, and reaction to insertion of tracheal tube and cuff inflation.

STATISTICAL ANALYSIS

Statistical tests used were analysis of variance (ANOVA), Chi-Square test, Repeated measures of ANOVA and Mann-Whitney U test.

RESULTS

Rocuronium in dosage of 0.3 mg/kg gaveclinically acceptable intubating conditions in 35% and 60% subjects at 60 s or 90 s, respectively, whereas in dosage of 0.6 mg/kg, intubating conditions were acceptable in 80% and 100% subjects intubated at 60 s and 90 s.

CONCLUSION

Rocuronium in dose of 0.3 mg/kg does not give clinically acceptable intubating conditions at 60 or 90 s but has shorter duration of action. Rocuronium in dose of 0.6 mg/kg gives clinically acceptable intubating conditions at 60 or 90 s, comparable to succinylcholine 1 mg/kg.

Rocuronium antagonized by sugammadex for series of electroconvulsive therapy (ECT) in a patient with pseudocholinesterase deficiency

We report the anesthetic management of a patient with catatonic schizophrenia and pseudocholinesterase deficiency, using the nondepolarizing neuromuscular blocking drug, rocuronium, reversed by its specific reversal agent, sugammadex, for a series of electroconvulsive therapy sessions. Rocuronium and sugammadex were used every 48 hours for 8 consecutive times and proved to be an effective and safe combination in a situation where succinylcholine was contraindicated.

The clinical effective dose of rocuronium for lightwand tracheal intubation after induction with alfentanil, propofol, and low concentrations of sevoflurane

BACKGROUND

The aim of this study was to determine the clinical effective dose of rocuronium for tracheal intubation using a lightwand after induction with propofol, alfentanil, and a low concentration of sevoflurane.

METHODS

Twenty-eight adults scheduled to undergo elective surgery lasting less than one hour were enrolled in this study. All patients received alfentanil (10 microg/kg) and propofol (1.5 mg/kg) for the induction of anesthesia. Tracheal intubation using a lightwand was attempted 3 minutes after administering rocuronium and mask ventilation with 2 vol% of sevoflurane. The initial rocuronium dose was 0.5 mg/kg. The rocuronium dose for consecutive patients, determined by Dixon's up-and-down method, was increased or decreased by 0.05 mg/kg according to the result of the previous patient. The mean arterial pressure and heart rate were recorded before induction, 1 min before intubation, 1 and 2 min after intubation.

RESULTS

The 50% clinical effective dose (cED(50)) of rocuronium for tracheal intubation using a lightwand was 0.20 +/- 0.05 mg/kg according to Dixon's up and down method. Isotonic regression revealed the cED(50) and cED(95) (95% confidence intervals) to be 0.20 mg/kg (0.10-0.3 mg/kg) and 0.35 mg/kg (0.16-0.49 mg/kg), respectively.

CONCLUSIONS

The cED(50) and cED(95) of rocuronium for tracheal intubation using the lightwand were 0.20 mg/kg and 0.35 mg/kg, respectively, after induction with alfentanil, propofol, and a low concentration of sevoflurane.

Pleth variability index predicts hypotension during anesthesia induction

BACKGROUND

The pleth variability index (PVI) is a new algorithm used for automatic estimation of respiratory variations in pulse oximeter waveform amplitude, which might predict fluid responsiveness. Because anesthesia-induced hypotension may be partly related to patient volume status, we speculated that pre-anesthesia PVI would be able to identify high-risk patients for significant blood pressure decrease during anesthesia induction.

METHODS

We measured the PVI, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) in 76 adult healthy patients under light sedation with fentanyl to obtain pre-anesthesia control values. Anesthesia was induced with bolus administrations of 1.8 mg/kg propofol and 0.6 mg/kg rocuronium. During the 3-min period from the start of propofol administration, HR, SBP, DBP, and MAP were measured at 30-s intervals.

RESULTS

HR, SBP, DBP, and MAP were significantly decreased after propofol administration by 8.5%, 33%, 23%, and 26%, respectively, as compared with the pre-anesthesia control values. Linear regression analysis that compared pre-anesthesia PVI with the decrease in MAP yielded an r value of -0.73. Decreases in SBP and DBP were moderately correlated with pre-anesthesia PVI, while HR was not. By classifying PVI >15 as positive, a MAP decrease >25 mmHg could be predicted, with sensitivity, specificity, positive predictive, and negative predictive values of 0.79, 0.71, 0.73, and 0.77, respectively.

CONCLUSION

Pre-anesthesia PVI can predict a decrease in MAP during anesthesia induction with propofol. Its measurement may be useful to identify high-risk patients for developing severe hypotension during anesthesia induction.

The effect of priming with rocuronium on onset time and intubation conditions during endotracheal intubation with low-dose rocuronium

BACKGROUND

A priming dose of rocuronium can shorten the onset time of neuromuscular blockade. The purpose of this study was to evaluate the effect of priming with rocuronium on the onset time and intubation conditions during tracheal intubation with low-dose rocuronium (0.35 mg/kg) and to compare results with those for rocuronium 0.45 mg/kg.

METHODS

One hundred twenty four patients were randomly allocated to three groups. Following induction of anesthesia, groups I and III received normal saline while group II received a priming dose of rocuronium (0.05 mg/kg). Three minutes after priming, groups I, II and III received, respectively, 0.45 mg/kg, 0.3 mg/kg and 0.35 mg/kg rocuronium. Intubation was performed 2 minutes after the administration of an intubating dose and intubation conditions were evaluated. Neuromuscular blockade was assessed by accelerography.

RESULTS

The proportion of cases having optimal intubation conditions in group I was higher than in groups II and III. There was no significant difference in the onset times among groups. Neuromuscular blockade at 60, 90 and 120 seconds after an intubating dose was similar among all groups except at 60 sec. Maximal blockade for group I was deep compared to groups II and III.

CONCLUSIONS

Rocuronium 0.35 mg/kg does not provide satisfactory intubation conditions. There are no effects on onset time and intubation conditions due to priming during tracheal intubation with rocuronium 0.35 mg/kg.

Should dosing of rocuronium in obese patients be based on ideal or corrected body weight?

BACKGROUND

Pharmacokinetic studies in obese patients suggest that dosing of rocuronium should be based on ideal body weight (IBW). This may, however, result in a prolonged onset time or compromised conditions for tracheal intubation. In this study, we compared onset time, conditions for tracheal intubation, and duration of action in obese patients when the intubation dose of rocuronium was based on three different weight corrections.

METHODS

Fifty-one obese patients, with a median (range) body mass index of 44 (34-72) kg/m2, scheduled for laparoscopic gastric banding or gastric bypass under propofol-remifentanil anesthesia were randomized into three groups. The patients received rocuronium (0.6 mg/kg) based on IBW (IBW group, n = 17), IBW plus 20% of excess weight (corrected body weight [CBW]20% group, n = 17), or IBW plus 40% of excess weight (CBW40% group, n = 17). Propofol was administered as a bolus of 200 mg and an infusion at 5 mg x kg(-1) x h(-1) and remifentanil was administered at 1.0 microg x kg(-1) x min(-1), both according to CBW40%. Neuromuscular function was monitored with train-of-four nerve stimulation and acceleromyography. The primary end point was duration of action, defined as time to reappearance of the fourth twitch in train-of-four.

RESULTS

The median (range) duration of action was 32 (18-49), 38 (25-66), and 42 (24-66) min in the IBW, CBW20%, and CBW40% groups, respectively (P = 0.001 for comparison of the IBW and CBW40% group). There were no significant differences in onset time (85 vs 84 vs 80 s) or in intubation conditions 90 s after administration of rocuronium.

CONCLUSIONS

In obese patients undergoing gastric banding or gastric bypass, rocuronium dosed according to IBW provided a shorter duration of action without a significantly prolonged onset time or compromised conditions for tracheal intubation.

Clinical implications of sugammadex

Sugammadex is a cyclodextrin molecule that encapsulates and inactivates rocuronium and vecuronium. As a result, any degree of neuromuscular block produced by rocuronium or vecuronium can be rapidly and completely reversed without autonomic effects. Because sugammadex is optimised for reversing rocuronium it is most likely to be used in conjunction with this drug. Sugammadex will allow deep levels of block to be maintained until the very end of surgery, and will allow block to be reversed at any time after rocuronium administration, even just a few minutes. The recommended dose-range is 2-16 mg.kg-1 (ascender), depending on the level of block. The availability of sugammadex reversal may increase the use of rocuronium, and decrease the use of suxamethonium and benzylisoquinoline neuromuscular blocking drugs. In addition, it will certainly increase pharmacy costs, which may be offset by faster recovery and discharge from the post-anesthesia recovery unit. Sugammadex may also change monitoring practices in that post-tetanic count will be required to quantify deep block, and quantitative monitoring of recovery may be driven by cost concerns in order to allow the use of the smallest dose of sugammadex that gives a satisfactory train-of-four ratio. Alternatively, monitoring may essentially be abandoned since a large dose of sugammadex will reliably reverse any degree of rocuronium-induced block. The ultimate clinical utility of sugammadex will be clear only after large-scale clinical use.

A comparison of intubation conditions and time-course of action with rocuronium and mivacurium for day case anaesthesia

BACKGROUND AND OBJECTIVE

To compare intubation conditions and time-course of action of rocuronium and mivacurium for day case anaesthesia.

METHODS

Fifty ASA I or II patients were enrolled. Anaesthesia was induced with propofol using a target controlled infusion system (target 6-8 microg mL(-1) ) and sufentanil (0.25 microg mL(-1). It was maintained with propofol (target 3.5-4.5 microg mL(-1) and 50% nitrous oxide in oxygen. Muscle relaxation was achieved with either mivacurium (0.15 mg kg(-1)) or rocuronium (0.3 mg kg(-1)). Neuromuscular transmission was monitored and recorded continuously by acceleromyography using a TOF-WATCH SX (Biometer; Denmark) with supramaximal train-of-four stimulation of the ulnar nerve. Tracheal intubation was carried out by an experienced anaesthetist blinded to the type of the muscle relaxant. Intubation conditions were evaluated according to a standard scheme (ease of laryngoscopy, position of vocal cords, airway reaction and limb movements).

RESULTS

Intubation conditions were good or excellent for both mivacurium 0.15 mg kg(-1) (good = 8%; excellent = 92%) and rocuronium 0.3 mg kg(-1) (excellent = 100%). Times to maximum blockade and clinical duration were not different.

CONCLUSIONS

There is no significant difference between mivacurium and rocuronium concerning the onset and the recovery of muscle relaxation. Rocuronium is an alternative to mivacurium for short procedures, without the risk of unexpected prolonged relaxation due to a possible defect in plasma cholinesterase.

Which muscle relaxants should be used in day surgery and when

PURPOSE OF REVIEW

After myorelaxants, myalgia and residual curarization may complicate recovery. Local anaesthesia and minimally invasive airway management make myorelaxants disputable in many outpatient procedures; nevertheless, neuromuscular blockade may be necessary to facilitate intubation or maintain muscle relaxation. Agent selection criteria are discussed.

RECENT FINDINGS

Reduced hospital time is not associated with central neuraxial or peripheral nerve block. To reduce the risk for residual block, neuromuscular monitoring is mandatory. Use of reversal agents should not be restricted, although studies have shown higher incidence of postoperative nausea and vomiting following their use. Higher succinylcholine dosage is followed by lower incidence of myalgia. The relationship between fasciculation and myalgia is unclear. Sodium channel blockers or nonsteroidal antiinflammatory drugs may prevent myalgia. Sugammadex functions as a chelating agent.

SUMMARY

Ear-nose-throat, open eye surgery and laparoscopy may demand myoresolution. Regional and minimally invasive anaesthesia are alternative solutions. Central and peripheral nerve blocks are associated with increased induction time, reduced pain scores, and decreased need for analgesics. Central neuraxial block, however, is associated with prolonged outpatient unit stay. Bad intubating conditions may cause pharyngo-laryngeal complications: the decision to avoid myorelaxants for tracheal intubation appears illogical. Incidence of postoperative residual curarization remains very high. Sugammadex offers new perspectives.

Tracheal intubating conditions and pharmacodynamics following cisatracurium in infants and children undergoing halothane and thiopental-fentanyl anesthesia

BACKGROUND

The aims of the present study were to determine the tracheal intubating conditions, onset time, duration of action, and hemodynamic responses following the administration of cisatracurium 0.15 mg x kg(-1) to infants and children.

METHODS

One hundred and eighty-one infants and children aged 1 month to 12 years were randomized to two groups to receive anesthesia with nitrous oxide-oxygen-halothane (group H) or nitrous oxide-oxygen-thiopental-fentanyl (group TF). Intubation conditions were assessed 120 s after cisatracurium administration using a 4-part scale. Neuromuscular transmission was monitored by recording the evoked compound electromyogram of the adductor pollicis.

RESULTS

The proportion of patients with excellent or good intubating conditions was similar in both groups (88 of 90, 98% in group H; 85 of 90, 94% in group TF). However, there was a significantly greater proportion of excellent intubating conditions in group H (79 of 90, 88%) compared with group TF (65 of 90, 72%) (P = 0.01) and recovery time was significantly longer in group H compared with group TF (P < 0.001). There was also a higher proportion of excellent intubating conditions in infants compared with older subjects (P = 0.02) and a shorter onset time (P < 0.001) and longer recovery time (P < 0.001) in younger compared with older patients. Changes in heart rate and arterial pressure were negligible 1 min following the cisatracurium administration.

CONCLUSIONS

Cisatracurium 0.15 mg x kg(-1) produces acceptable intubating conditions at 120 s in the great majority of infants and children. Anesthesia background and age have significant effects on intubating conditions and duration of action of cisatracurium.

Pharmacodynamics of rocuronium 0.3 mg kg(-1) in adult patients with and without renal failure

BACKGROUND AND AIM

The neuromuscular effects of a bolus dose of rocuronium 0.6 mg kg(-1) under propofol anaesthesia in renal failure patients are prolonged compared to healthy patients. The present study aims to describe the neuromuscular effects of 0.3 mg kg(-1) rocuronium under propofol anaesthesia in patients with renal failure and to compare these effects with healthy control patients.

METHODS

With institutional approval and informed consent, 18 healthy patients and 18 patients with renal failure took part in this prospective open label study. The renal failure patients were undergoing either renal transplantation or insertion of a shunt. Rocuronium 0.3 mg kg(-1) was given intravenously after induction of anaesthesia with propofol 1-2 mg kg(-1) and fentanyl 2 microg kg(-1). Propofol 6-12 mg kg(-1) h(-1) was used for maintenance of anaesthesia. Four acceleromyographic responses of the thumb after supramaximal stimulation of the ulnar nerve using surface electrodes at 2 Hz every 15 s were measured and recorded. The onset time, the time to recovery of the first twitch to 25% recovery and the time to a train-of-four ratio of 0.7 were all recorded. Wilcoxon rank sum testing was used to compare the pharmacodynamics and to see if medication, gender or electrolytes influenced the duration of the block. P < 0.05 was significant.

RESULTS

No statistical differences were seen in the neuromuscular blocking effects of rocuronium between the two groups but there was a significant difference (P < 0.00001) in the variability of the total duration of the block.

CONCLUSIONS

Rocuronium 0.3 mg kg(-1) is suitable for use in patients with renal failure when endotracheal intubation and neuromuscular block for a short period of time are needed. Tracheal intubation is facilitated within 4 min and the block can be antagonized within 20 min.

The Effect of Nitrous Oxide on the Dose-Response Relationship of Rocuronium

It has been generally assumed that nitrous oxide (N(2)O) enhances the effects of nondepolarizing muscle relaxants only weakly if at all. More recent evidence suggests that drug potency may be more intense under N(2)O anesthesia compared with total IV anesthesia (TIVA). However, the magnitude of this effect has not been well defined. We measured the 50% effective dose of rocuronium in 35 patients receiving N(2)O-propofol-opioid anesthesia and a comparable group receiving TIVA. A single dose of rocuronium was given to each patient and drug potency was calculated for each individual from the Hill equation assuming a log-dose/logit slope of 4.5. In both groups, the relaxant was administered 15 min after induction of anesthesia. Neuromuscular function was measured using electromyography with single stimuli at 0.10 Hz. We measured a 50% effective dose of 0.209 +/- 0.051 mg/kg during TIVA and of 0.166 +/- 0.041 mg/kg during N(2)O anesthesia, a decrease of 20% (P < 0.001). The clinical importance of this effect must be considered modest; however, estimates of potency that are usually obtained during N(2)O anesthesia may underestimate drug requirements at the time of induction of anesthesia.

Muscle relaxation and increasing doses of propofol improve intubating conditions

PURPOSE

Muscle relaxants and anesthetics are usually associated during intubation. However, their relative role to facilitate the process is not clearly defined. This study was designed to determine, during intubation: i). the relative role of anesthetics and atracurium-induced neuromuscular block and; ii). the effect of different doses of propofol in the presence of complete muscle block.

METHODS

Patients were randomized to four groups and received fentanyl and a standardized anesthetic procedure. Patients from groups high (H; n = 45), medium (M; n = 48) and low (L; n = 47) received 2.5 mg x kg(-1), 2.0 mg x kg(-1), and 1.5 mg x kg(-1) of propofol respectively. Atracurium (0.5 mg x kg(-1)) was then injected and tracheal intubation performed once complete block was achieved at the orbicularis oculi. Patients from group without atracurium (WA; n = 20) received propofol as in group H. Intubation was performed at the expected onset time of action of atracurium.

RESULTS

Using the same dose of propofol, the incidence of good or excellent intubating conditions was 35% without atracurium and 95% with atracurium (P < 0.0001). In patients receiving atracurium, clinically acceptable intubating conditions were more frequently achieved in groups receiving the highest propofol doses (group H or M vs group L; P < 0.03).

CONCLUSION

Our study confirms the interaction between anesthesia and muscle relaxation to produce adequate intubating conditions. In the conditions described, intubating conditions were more dependent on atracurium-induced neuromuscular blockade than on anesthetics, but both atracurium and propofol improved intubating conditions.

Newer neuromuscular blocking agents: how do they compare with established agents?

Rapacuronium bromide (rapacuronium; ORG-9487) is a nondepolarising muscle relaxant (NMBA) with a low potency [90% effective dose (ED90) 1 mg/kg], which to some extent is responsible for its rapid onset of action. Because of the high plasma clearance (5.3 to 11.1 mg/kg/min) of rapacuronium, its clinical duration of action following single bolus doses up to 2 mg/kg in adults is short (i.e. <20 minutes). Rapacuronium forms a pharmacologically active 3-desacetyl metabolite, ORG-9488, which may contribute to a delay in spontaneous recovery after repeat bolus doses or infusions. After rapacuronium 1.5 mg/kg clinically acceptable intubating conditions are achieved within 60 to 90 seconds in the majority of adult and elderly patients undergoing elective anaesthesia. However, in a rapid-sequence setting. intubating conditions are less favourable after rapacuronium 1.5 to 2.5 mg/kg than after succinylcholine. The most prominent adverse effects of rapacuronium (tachycardia, hypotension and bronchospasm) are dose-related, and in particular pulmonary adverse effects are observed more frequently under conditions of a rapid-sequence induction in adults. Therefore, it seems worthwhile to consider only doses of rapacuronium < or = 1.5 mg/kg to facilitate rapid tracheal intubation, and to use succinylcholine or rocuronium rather than rapacuronium in a rapid-sequence setting. Rapacuronium, however, is a suitable alternative to mivacurium chloride (mivacurium) and succinylcholine for short procedures (e.g. ambulatory anaesthesia). Rocuronium bromide (rocuronium) is a relatively low-potent, intermediateacting NMBA. Its main advantage is the rapid onset of neuromuscular block whereby good or excellent intubating conditions are achieved within 60 to 90 seconds after rocuronium 0.6 mg/kg (2 x ED95), and within 60 to 180 seconds after smaller doses (1 to 1.5 x ED95). Larger doses of rocuronium (> or = 1 mg/kg) seem to be suitable for rapid-sequence induction under relatively light anaesthesia. However, it is still a matter of controversy whether, in the case of an unanticipated difficult intubation, the long duration of rocuronium administered in such large doses outweighs the many adverse effects of succinylcholine. Rocuronium has mild vagolytic effects and does not release histamine, even when administered in large doses. Rocuronium is primarily eliminated via the liver and its pharmacokinetic profile is similar to that of vecuronium bromide (vecuronium). Unlike vecuronium, rocuronium has no metabolite. Cisatracurium besilate (cisatracurium), the IR-cis, 1'R-cis isomer of atracurium besilate (atracurium) is approximately 4 times more potent than atracurium. The onset time of cisatracurium is significantly slower than after equipotent doses of atracurium. The recommended intubating dose is 0.15 to 0.2 mg/kg (3 to 4 times ED95). Over a wide range of clinically relevant doses the recovery properties of cisatracurium are affected by neither the size of the bolus dose nor by the duration of infusion. Unlike atracurium, cisatracurium does not trigger histamine release. Like atracurium, cisatracurium undergoes Hofmann elimination. In contrast to atracurium, cisatracurium does not undergo hydrolysis by nonspecific plasma esterases. Moreover, about 77% of the drug is cleared by organ-dependent mechanisms.

Reexamined: the recommended endotracheal intubating dose for nondepolarizing neuromuscular blockers of rapid onset

The results of any study of the relative importance of anesthetic depth versus intensity of neuromuscular block on conditions for endotracheal intubation can be manipulated by the investigator. Several independent factors, such as the depth of hypnosis induced, the interval between drug administration and laryngoscopy, the onset profile of the muscle relaxant, and the multiple of the 95% effective dose given, must be controlled. We attempted to design an induction sequence that provided good to excellent conditions for laryngoscopy and endotracheal intubation within 75-90 s of muscle relaxant administration with doses smaller than often suggested, while still administering only customary amounts of hypnotics and opioids. Alfentanil 12.5 microg/kg, propofol 2.0 mg/kg, and a test drug were administered rapidly. The test drugs were saline 0.05 mL/kg (n = 10), rapacuronium 1.0 or 1.2 mg/kg, or rocuronium 0.50 mg/kg (n = 30 each). Laryngoscopy was commenced 75 s after the test drug. Clinically acceptable conditions for intubation were achieved in all subjects after rocuronium or rapacuronium 1.2 mg/kg and in 28 of 30 patients after rapacuronium 1.0 mg/kg. In the Saline group, only 3 individuals achieved a good or excellent rating, and intubation was impossible in 2 of 10 individuals. For muscle relaxants of low potency, doses only 1.5 times the 95% effective dose can provide very satisfactory conditions for intubation if laryngoscopy is delayed to 75 s after drug administration.

IMPLICATIONS

The dose of muscle relaxant usually recommended for facilitating tracheal intubation approximates at least two times the drug's effective dose (ED(95)). When the muscle relaxant in question has a rapid onset of action, this intubation dose may be decreased to 1.5 times the ED(95).

Probability of acceptable intubation conditions with low dose rocuronium during light sevoflurane anaesthesia in children

BACKGROUND

To define the rocuronium doses which would provide 50%, 90%, and 95% probability of 'acceptable' intubation conditions during light sevoflurane anaesthesia, we studied 60 children aged 2-7 years in a prospective, randomised, assessor blinded study.

METHODS

After mask ventilation with 1 MAC sevoflurane/N2O for 17+/-1 (x+/-SD) min we administered rocuronium (either 0.15, 0.22, 0.3, 0.5, or 1.0 mg. kg(-1)) or placebo, and quantified the evoked force of the adductor pollicis muscle. Intubation conditions were assessed before and 2 min after injection of the test drug.

RESULTS

Intubation conditions were improved significantly with rocuronium and scored 'acceptable' in 70%, 90%, and 100% of the children after injection of rocuronium 0.15, 0.22, and 0.3 mg x kg(-1), respectively. In parallel, twitch tension decreased to 53% (6-100), 26% (11-100), and 11% (0-19) of baseline (median (range)). Recovery of train-of-four ratio to 0.8 was achieved 13 (7-19), 16 (8-28), and 27 (23-44) min after injection of the respective rocuronium doses. Higher rocuronium doses did not further improve intubation conditions but only prolonged time of neuromuscular recovery. Logistic regression analysis revealed that rocuronium 0.11 (CI 0.05-0.16), 0.21 (0.14-0.28), and 0.25 (0.15-0.34) mg x kg(-1) provides a 50%, 90%, and 95% probability of 'acceptable' intubation conditions in children during 1 MAC sevoflurane/N2O anaesthesia, respectively. Furthermore, we calculated that force depression of adductor pollicis muscle to 81% (CI 72-90), 58% (42-74), and 50% (29-71) of baseline is associated with 50%, 90%, and 95% probability of 'acceptable' intubation conditions.

CONCLUSIONS

Submaximal depression of muscle force with low dose rocuronium improves intubation conditions in children during light sevoflurane anaesthesia while allowing rapid recovery of neuromuscular function. However, when using low dose rocuronium neuromuscular monitoring may be helpful to detect children with inadequate response to the relaxant so as to avoid an unsuccessful intubation attempt.

Rocuronium versus succinylcholine-atracurium for tracheal intubation and maintenance relaxation during propofol anesthesia

STUDY OBJECTIVES

To compare the onset and offset time (clinical duration), and intubating conditions obtained with rocuronium bromide 0.6 mg/kg and succinylcholine 1.0 mg/kg after induction with propofol and fentanyl; and to compare rocuronium with atracurium for maintenance during propofol anesthesia.

DESIGN

Prospective, open-label, parallel group comparative, randomized study.

SETTING

Operating rooms of a university hospital.

PATIENTS

30 ASA physical status I and II adult patients scheduled for elective surgeries with general anesthesia.

INTERVENTIONS

Patients premedicated with midazolam 2 mg were anesthetized with fentanyl 2 microg/kg followed by propofol 2.5 mg/kg and muscle relaxants. Group 1 (n = 15) received succinylcholine 1.5 mg/kg and Group 2 (n = 16) received rocuronium bromide 0.6 mg/kg. Intubation was performed 60 seconds after the administration of muscle relaxant. Patients in Group 1 received atracurium and patients in Group 2 received rocuronium for maintenance if required.

MEASUREMENTS

The ease of intubation was scored using a scale of 1 to 4. Onset and offset time monitored with evoked twitch response of the adductor pollicis were recorded.

MAIN RESULTS

Intubation was successful in all patients and there was no difference in scores between the two groups. Although onset time was shorter with succinylcholine than with rocuronium, neuromuscular blockade was successfully antagonized in both groups, and the recovery profile was not different between the two groups.

CONCLUSIONS

Rocuronium bromide at a dose of 0.6 mg/kg, when used with propofol and fentanyl for induction, provides intubating conditions similar to succinylcholine 1.0 mg/kg at 1 minute. The actual onset time and offset time, however, are significantly longer with rocuronium. There was no difference between atracurium and rocuronium as a maintenance drug. Rocuronium is suitable for surgical procedures greater than 30 minutes, eliminating the need for an additional relaxant to succinylcholine.

Tracheal intubation after induction of anesthesia in children with propofol--remifentanil or propofol-rocuronium

PURPOSE

To compare the intubating conditions after remifentanil-propofol with those after propofol-rocuronium combination with the aim of determining the optimal dose of remifentanil.

METHODS

In a randomized, double-blind study 80 healthy children aged three to nine years were assigned to one of four groups (n=20): 2 or 4 microgxkg(-1) remifentanil (Re2 or Re4); 2 microgxkg(-1) remifentanil and 0.2 mgxkg(-1) rocuronium (Re2-Ro0.2); 0.4 mgxkg(-1) rocuronium (Ro0.4). After atropine, remifentanil was injected over 30 sec followed by 3.5 mgxkg(-1) propofol and rocuronium. After 60 sec, laryngoscopy and intubation were attempted. Intubating conditions were assessed as excellent, good or poor based on ease of ventilation, jaw relaxation, position of the vocal cords, and coughing to intubation.

RESULTS

In all children intubation was successful. Overall intubating conditions were better (P < 0.01), and the frequency of excellent conditions, 85%, was higher (P < 0.01) in the Re4 group than in the Ro0.4 group. No child manifested signs of muscular rigidity. In the remifentanil groups, arterial pressure decreased 11-13% and heart rate 6-9% after anesthetic induction, and remained at that level throughout the study.

CONCLUSION

The best intubating conditions were produced by the combination of 4 microgxkg(-1) remifentanil and 3.5 mgxkg(-1) propofol. It provided excellent or good intubating conditions in all children without causing undue cardiovascular depression.

Remifentanil and propofol without muscle relaxants or with different doses of rocuronium for tracheal intubation in outpatient anaesthesia

BACKGROUND

The use of muscle relaxants in outpatient anaesthesia is controversial; some authors recommend an induction regimen including propofol and opioids without muscle relaxants. This study evaluated the requirements for rocuronium after remifentanil/propofol.

METHODS

We examined in four groups of ASA I-II patients (n= 30 for each) the intubating conditions three minutes after induction of anaesthesia with remifentanil 0.5 microg kg(-1) min(-1), propofol 2 mg kg(-1) without muscle relaxants or with different doses of rocuronium (0.6 mg kg(-1), 0.45 mg kg(-1), 0.3 mg kg(-1)) applying the criteria proposed by the Copenhagen Consensus Conference. In the second part of the study the time course of neuromuscular block was determined by electromyography using train-of-four (TOF) stimulation. To this end, another 60 ASA I-II patients were randomly assigned to receive remifentanil 0.5 microg kg(-1) min(-1), propofol 2 mg kg(-1) and either rocuronium 0.6 mg kg(-1), 0.45 mg kg(-1), 0.3 mg kg(-1), or 0.3 mg kg(-1) followed by neostigmine 40 microg kg(-1) and atropine 20 microg kg(-1) at a T1 recovery of 10% (n=15 for each).

RESULTS

Intubating conditions were good or excellent in 30 patients after rocuronium 0.6 mg kg(-1) and in 18 patients when rocuronium was omitted (P<0.01). After 0.45 mg kg(-1) and 0.3 mg kg(-1) rocuronium the numbers were 29 and 30 patients, respectively. Reducing rocuronium from 0.6 mg kg(-1) to 0.45 mg kg(-1) or 0.3 mg kg(-1) increased the onset time from 136 (35) s to 199 (34) s and 249 (52) s (mean (SD)), (P<0.01); the clinical duration decreased from 38 (10) min to 24 (8) min and 16 (5) min, respectively (P<0.01); and the duration to a TOF-ratio of 0.8 decreased from 60 (11) min to 45 (9) min and 34 (7) min (P<0.01). After rocuronium 0.3 mg kg(-1) this time interval further decreased to 22 (3) min when neostigmine was given at a T1 of 10% (P<0.01 compared with spontaneous recovery after rocuronium 0.3 mg kg(-1)).

CONCLUSION

After remifentanil/propofol intubation conditions were poor in 40% of patients without muscle relaxants; adding reduced doses of rocuronium to this regimen improved the intubation conditions significantly. In addition, reducing the initial dose of rocuronium markedly shortened its time course of action.

Comparison of sevoflurane and propofol with rocuronium for modified rapid-sequence induction of anaesthesia

We compared the use of sevoflurane and propofol with three different doses of rocuronium for modified rapid-sequence induction of anaesthesia. One hundred and forty adult patients were randomly allocated to have a rapid-sequence intravenous induction with propofol 2-3 mg.kg-1 (group P) or an inhalational induction with sevoflurane 8% in oxygen, using a vital capacity technique (group S). Following loss of the eyelash reflex, cricoid pressure was applied and 20 patients in each group were administered rocuronium 0.3 (groups P/0.3 and S/0.3), 0.45 (groups P/0.45 and S/0.45) or 0.6 (groups P/0.6 and S/0.6) mg.kg-1. An additional 10 patients in each group received only saline placebo in place of the muscle relaxant (groups P/Saline and S/Saline). Laryngoscopy was started 60 s later and intubating conditions evaluated by a blinded anaesthetist according to a standard scoring system. Intubating conditions were acceptable in one patient and no patient, respectively, following induction with sevoflurane and propofol without the muscle relaxant. The conditions were acceptable in 30, 55 and 90% of subjects with sevoflurane induction, and in 45, 80 and 90% of subjects with propofol induction following 0.3, 0.45 and 0.6 mg.kg-1 of rocuronium, respectively (no significant difference for each dose of rocuronium). The present study shows that intubating conditions during a rapid-sequence induction using rocuronium 0.6 mg.kg-1 following induction of anaesthesia with sevoflurane or propofol are similar.