Comparison of rocuronium and suxamethonium for rapid tracheal intubation in children

BACKGROUND: The purpose of our study was to determine whether a smaller dose of rocuronium than previously reported could provide similar intubating conditions to suxamethonium during rapid-sequence induction of anaesthesia in children. METHODS: One hundred and twenty ASA I, unpremedicated children, aged 1-10 years, who were undergoing elective surgery, were randomized into three groups to receive rocuronium 0.6 mg.kg-1, rocuronium 0.9 mg.kg-1 or suxamethonium 1.5 mg.kg-1. The study was double-blinded, anaesthesia and timing of injection was standardized to alfentanil 10 microg.kg-1, thiopentone 5 mg.kg-1 and the study drug. Intubation was attempted at 30 s after injection of neuromuscular relaxant and intubating conditions graded as excellent, good, poor or impossible. RESULTS: All 120 children were successfully intubated within 60 s without need for a second attempt after administration of neuromuscular relaxant. Differences between suxamethonium and rocuronium 0.6 mg.kg-1 and between the two doses of rocuronium were statistically significant (P=0.016 and 0.007, respectively). CONCLUSIONS: Rocuronium 0.9 mg.kg-1 provides similar intubating conditions to suxamethonium 1.5 mg.kg-1 during modified rapid-sequence induction using alfentanil and thiopentone in children (P=0.671). Rocuronium 0.6 mg.kg-1 was inadequate.     

Comparison of suxamethonium and different combinations of rocuronium and mivacurium for rapid tracheal intubation in children

The use of suxamethonium in children is associated with undesirable side effects. The synergistic effect of a rocuronium-mivacurium combination can be considered as an acceptable alternative to suxamethonium in clinical practice. The calculated ED50 of the rocuronium-mivacurium mixture was only 62% of the predicted value assuming a purely additive interaction. The use of this combination has not been evaluated in children. In this two-part study, we assessed the intubating conditions and pharmacodynamics of suxamethonium, rocuronium, mivacurium or a rocuronium-mivacurium combinations in children. We studied 120 ASA I children of both sexes, aged 3-10 yr. Children were premedicated with trimeprazine 2 mg kg-1 orally, and received fentanyl 2 micrograms kg-1 and propofol 2 mg kg-1 for induction of anaesthesia. They were allocated randomly to receive one of the following drugs or drug combinations: suxamethonium 1.0 mg kg-1, mivacurium 0.2 mg kg-1, rocuronium 0.6 or 0.9 mg kg-1, mivacurium 0.1 mg kg-1 with rocuronium 0.3 mg kg-1 or mivacurium 0.15 mg kg-1 with rocuronium 0.45 mg kg-1. In part 1, 60 s after administration of the neuromuscular blocking drug or drug combination, tracheal intubation was performed in 60 children by mimicking rapid sequence induction, and intubating conditions were evaluated by a blinded investigator according to a standard score. In part 2, neuromuscular monitoring was established before administration of neuromuscular blocking agent(s) and the time from injection of drug or drug combination until complete ablation of T1 (onset) and recovery of T1 to 25% (duration) were recorded in another 60 children. The frequency of distribution of excellent or good intubating conditions in the higher dose of rocuronium and the combination groups were similar to those in the suxamethonium group, but significantly different (P < 0.05) from those in the mivacurium group. Mean onset time was faster in the suxamethonium (55.1 (SD 11.4) s), rocuronium 0.9 mg kg-1 (70.5 (37.7) s), mivacurium 0.1 mg kg-1 with rocuronium 0.3 mg kg-1 (67 (35.9) s) and mivacurium 0.15 mg kg-1 with rocuronium 0.45 mg kg-1 (55 (26.7) s) groups compared with the mivacurium 0.2 mg kg-1 (116 (26.8) s) and rocuronium 0.6 mg kg-1 (97.9 (29) s) groups. This study demonstrated that the combination of rocuronium 0.45 mg kg-1 and mivacurium 0.15 mg kg-1 could possibly be considered as an acceptable alternative to suxamethonium when rapid sequence induction of anaesthesia is indicated in children because it provides uniform excellent intubating conditions and complete neuromuscular block in < 60 s.      

Influence of induction technique on intubating conditions after rocuronium in adults: comparison with rapid-sequence induction using thiopentone and suxamethonium

We have assessed the effect of anaesthetic technique on intubating conditions after rocuronium 0.6 mg kg-1 in four groups (n = 25 each) of unpremedicated patients in whom anaesthesia was induced with either thiopentone 5 mg kg-1 or propofol 2.5 mg kg-1 alone, or supplemented with alfentanil 20 micrograms kg-1. Fifty control patients were anaesthetized with thiopentone followed by suxamethonium. Laryngoscopy was commenced at 45 s. Overall intubating conditions after rocuronium were similar to those after suxamethonium (good and excellent > or = 96%) only when alfentanil was part of the induction regimen. However, intubation time was similar in all five groups and averaged 55 (SD 3.2) s, and the tube could be passed through open vocal cords within 70 s. After rocuronium the response of the diaphragm to intubation was more pronounced in the two groups of patients not receiving alfentanil (P < 0.0001) and in patients anaesthetized using propofol with alfentanil (P < 0.01) than in the control group. Opioids (in doses equivalent to alfentanil 20 micrograms kg-1) constitute an integral part of an induction regimen containing rocuronium 0.6 mg kg-1, regardless of whether or not thiopentone or propofol is used, in order to achieve overall intubating conditions similar to those after suxamethonium.      

Comparison of intubating conditions after rocuronium and suxamethonium following "rapid-sequence induction" with thiopentone in elective cases

Background : Rocuronium (Org 9426) was shown to have the fastest onset of action of all currently available non-depolarizing neuromuscular blocking drugs and to provide intubating conditions similar to those of suxamethonium 60 to 90 s after administration. We compared the intubating conditions after rocuronium and suxamethonium following rapid-sequence induction of anaesthesia.
Methods : Fifty unpremedicated patients of ASA physical status I or II, scheduled for elective surgery were studied. Anaesthesia was induced with thiopentone 6 mg kg^-1 followed randomly by suxamethonium 1 mg kg^-1 or rocuronium 0.6 mg kg^-1 and, 45 s later, intubation was commenced. Muscle fasciculations, intubating conditions and intubation time, haemodynamic variables and oxygenation were assessed.
Results : Intubation time did not differ between suxamethonium (9.8±2.2 s) (mean±SD) and rocuronium (10.5±2.9 s), respectively. Intubating conditions were clinically acceptable (good or excellent) in all patients given suxamethonium and in 96% of the patients given rocuronium. However, the condition of the vocal cords was better (P<0.05) and diaphragmatic response to intubation was less pronounced with suxamethonium (P<0.05). Changes in heart rate and arterial blood pressure were similar in both groups.
Conclusion : The authors conclude that rocuronium is a suitable alternative to suxamethonium for rapid tracheal intubation even under unsupplemented thiopentone anaesthesia, at least in elective, otherwise healthy patients. Its use for rapid-sequence induction under emergency conditions, however, needs further investigation.     

A large simple randomized trial of rocuronium versus succinylcholine in rapid-sequence induction of anaesthesia along with propofol

Background: Rocuronium has an onset of action more rapid than other non-depolarizing neuromuscular blocking agents, but it is unclear whether it and succinylcholine give equivalent intubating conditions during rapid-sequence induction of anaesthesia. We performed this study to answer the question – are there clinically relevant differences between the use of rocuronium and succinylcholine to secure acceptable intubating conditions during rapid-sequence induction of anaesthesia with propofol? Methods: Anaesthesia was induced using propofol 2.5 mg/kg in 349 ASA physical status grade I–IV patients who were undergoing either elective or emergency surgery. Propofol was followed immediately by either rocuronium 0.6 or 1 mg/kg or succinylcholine 1.0 mg/kg (randomly selected). Fifty seconds after the end of muscle relaxant injection laryngoscopy was performed and intubating conditions were graded by an experienced anaesthetist blind to the muscle relaxant allocation. This study design was selected so that a 10% difference in clinically acceptable intubating conditions between drugs would be detectable. Results: In this setting rocuronium 1.0 mg/kg provided superior intubating conditions compared with rocuronium 0.6 mg/kg. The incidence of clinically acceptable intubating conditions with rocuronium 1.0 mg/kg and succinylcholine 1.0 mg/kg was 93.2% and 97.1% respectively, the difference being ?3.9% (95% C.I. ?9.7% to 1.9%). Conclusion: Rocuronium 1.0 mg/kg given along with propofol in a rapid-sequence induction of anaesthesia is clinically equivalent to succinylcholine 1.0 mg/kg.     

Does rocuronium displace the position of suxamethonium?

A full stomach patient often requires a rapid sequence induction (RSI) technique to protect against gastric aspiration. Suxamethonium is the most common muscle relaxant used because it has a fast onset and a short duration. Unfortunately it can have serious side effects as a result of its membrane depolarizing effect and release of potassium. Rocuronium has been suggested to create intubating conditions similar to suxamethonium. However, it has been proved that suxamethonium creates superior intubation conditions to rocuronium in a large meta-analysis comparing intubation conditions. Once Org 25969 (sugammadex) is available to rapidly bind rocuronium and reverse its action, rocuronium may replace succinylcholine for rapid-sequence induction.     

Onset of neuromuscular blockade and intubating conditions one minute after the administration of rocuronium in children

In a blinded randomized study intubating conditions were compared at one min following intravenous induction with propofol and either suxamethonium 1.0 mg·kg⁻¹, or rocuronium 0.6 mg·kg⁻¹. Onset time to maximal twitch depression, % block at one minute and clinical duration (time to 25% recovery) were measured. Sixty children undergoing elective tonsillectomy were recruited. Onset time [42 s ( SD 11 s)] and clinical duration [3.3 min ( SD 1.0 min)] in the suxamethonium group was significantly ( P <0.001) less than in the rocuronium group [92 s (41 s)] and [24.2 min (6.6 min)] respectively. The median twitch height at one minute for suxamethonium was 0% (range 0–8%) and significantly greater ( P <0.001) at 5% (range 0–22%) for rocuronium. Despite this there was no difference in the intubating conditions at one minute with 25 excellent/5 good in the suxamethonium group and 27 excellent/3 good in the rocuronium group. We conclude that rocuronium 0.6 mg·kg⁻¹ gives optimal intubating conditions at one minute in children.     

The influence of fentanyl vs. s-ketamine on intubating conditions during induction of anaesthesia with etomidate and rocuronium

BACKGROUND AND OBJECTIVE: In the present study, we investigated the combination of etomidate and s-ketamine with regard to its suitability for modified rapid-sequence induction using rocuronium for muscle relaxation. METHODS: In a prospective, randomized and double-blinded study, 90 patients were assigned to one of three groups for induction of anaesthesia in combination with etomidate (0.3 mg kg-1) and muscle relaxation with rocuronium (0.6 mg kg-1). The groups were as follows: (a) control, i.e. placebo; (b) fentanyl, fentanyl (1.5 microg kg-1); (c) ketamine, s-ketamine (0.5 mg kg-1). Tracheal-intubating conditions after 1 min were classified as excellent, good or poor. During the induction of anaesthesia, arterial pressure and heart rate were measured every 60 s. RESULTS: Intubating conditions were best using etomidate and s-ketamine (23 excellent, 7 good, 0 poor) compared with the control (8, 16, 6 respectively) and fentanyl groups (7, 21, 2 respectively) (P < 0.01). While heart rate and arterial pressure remained stable in the control and fentanyl groups during induction, both significantly increased in the ketamine group (P < 0.01). CONCLUSIONS: The combination of etomidate and s-ketamine for anaesthesia induction produces mostly excellent intubating conditions after 60 s using only 0.6 mg kg-1 of rocuronium. This combination of drugs may be a useful alternative, if succinylcholine needs to be avoided, for modified rapid-sequence induction.     

The onset of neuromuscular block at the masseter muscle as a predictor of optimal intubating conditions with rocuronium.

After an intubating dose of rocuronium satisfactory intubating conditions are achieved before the onset time at the adductor pollicis. We examined the possibility that measurement of the relaxation of the masseter muscle is a more appropriate guide when determining the intubating time. Simultaneous accelerometry with a 0.1-Hz single twitch stimulation of the chin and thumb was performed in 20 patients after 0.6 mg kg-1 rocuronium. We observed a significantly more brief mean lag time and onset time at the masseter muscle (22.5 and 61 vs. 32.5 and 160 s). The corresponding mean relaxation at the onset time was also significantly more pronounced at the masseter muscle (99.6 vs. 97.6%). A mean onset time at the masseter muscle of 61 s as produced by rocuronium corresponds clinically with excellent or good intubating conditions. From these results, we suggest that measurement of the onset time of muscle relaxation at the masseter muscle appears to be a better predictor of good intubating conditions than measurements made using the adductor pollicis muscle after administration of rocuronium.     

Suxamethonium administration prolongs the duration of action of subsequent rocuronium

BACKGROUND AND AIM: Rocuronium may be given to patients for intubation and also after they have received suxamethonium for intubation. The neuromuscular profile of rocuronium given after recovery from suxamethonium may not be identical to that when rocuronium has been given alone. The neuromuscular effects of suxamethonium and rocuronium, and their effects on intraocular pressure (IOP), heart rate (HR) and arterial pressure were also recorded. METHODS: Thirty patients were randomly allocated to receive either 0.6mg kg(-1) rocuronium (n = 15) or 1 mg kg(-1) suxamethonium (n = 15) for intubation. Anaesthesia was first induced using propofol 2.5 mg kg(-1) and fentanyl 2 microg kg(-1) and maintained with propofol 6-12 mg kg(-1) h(-1). The response of the thumb to supramaximal train-of-four (TOF) ulnar nerve stimulation at the wrist was measured using a mechanomyograph. In the suxamethonium group, when the first twitch of the TOF had recovered to 90%, rocuronium 0.6 mg kg(-1) was administered. Before administration of relaxant, baseline readings of HR, arterial pressure and IOP were measured until stable, then the appropriate relaxant administered. Thereafter, all readings were repeated at 30, 90, 150, 210 and 270 s. Tracheal intubation was performed 300 s after the intubating dose and all recordings repeated 30 s later. Mechanomyographic monitoring was continued until 70% TOF recovery. RESULTS: Suxamethonium had a more rapid onset than rocuronium (49s vs. 74s, P < 0.0001). The onset time of rocuronium after suxamethonium was significantly reduced (56 s) and the time to recover to a TOF of 70% following rocuronium was increased by previous suxamethonium administration (47 vs. 58 min, P < 0.05). Suxamethonium caused a marked rise in IOP (>30%) and HR (>10%) while rocuronium had little effect on either. CONCLUSION: Previous suxamethonium administration decreases the onset time and increases the duration of action of rocuronium. Unlike suxamethonium, rocuronium has few cardiovascular effects and causes little change in IOP.     

COMPARISON OF INTUBATING CONDITIONS AFTER ADMINISTRATION OF ORG 9426 (ROCURONIUM) AND SUXAMETHONIUM

We have assessed intubating conditions after administrationof Org 9426 (rocuronium) 600 fig kg^–1 at 60 or 90s ingroups of 20 patients anaesthetized with thiopentone, nitrousoxide in oxygen and small doses of fentanyl, and compared thedata with those obtained after suxamethonium 1 mg kg^–1in similar groups of patients. The influence of prior suxamethoniumadministration on the potency of Org 9426 was studied also byconstructing a dose-response curve. Intubating conditions afterOrg 9426 were found to be clinically acceptable (good or excellent)in 95% of patients at 60 s and in all patients at 90 s and inall patients at both times after suxamethonium. The averagetime for the onset of block following Org 9426 at this dosewas 89 s (which is shorter than with any of the currently availablenon-depolarizing neuromuscular blocking drugs); the durationof clinical relaxation (25% recovery of twitch height) 30 min.Prior administration of suxamethonium did not appear to influencethe potency of Org 9426.     

Rapid tracheal intubation with propofol, alfentanil and a standard dose of vecuronium

We studied 60 ASA I patients with Mallampati grade 1 airways to compare emergency intubating conditions with either alfentanil 20 micrograms kg- 1, propofol 2.5 mg kg-1 and vecuronium 0.1 mg kg-1, or with thiopentone 5 mg kg-1 and suxamethonium 1 mg kg-1. Ease of laryngoscopy, vocal cord status and cough response were graded. The trachea of all patients was intubated; 83% of patients in the alfentanil-propofol-vecuronium group and 86% in the thiopentone-suxamethonium group were considered to have satisfactory intubating conditions at 60 s. We conclude that the combination of alfentanil 20 micrograms kg-1, propofol 2.5 mg kg-1 and vecuronium 0.1 mg kg-1 provided adequate conditions for rapid tracheal intubation.      

Influence of induction of anaesthesia on intubating conditions one minute after rocuronium administration: comparison of ketamine and thiopentone

We compared the effect of thiopentone and ketamine on intubating conditions after rocuronium 0.6 mg.kg-1 in two groups of patients (n = 16 each), aged 21-44 years, undergoing elective surgery. Premedication consisted of alprazolam 1 mg by mouth 1 h before surgery. All patients received midazolam 2 mg intravenously 2 min before intravenous administration of thiopentone 5 mg.kg-1 or ketamine 2.5 mg.kg-1. Muscle relaxation was provided by rocuronium 0.6 mg.kg-1. One minute after rocuronium administration, tracheal intubation was performed within 15 s by a skilled anaesthetist blinded to the treatment group assignment. Intubating conditions were graded as excellent, good, fair or poor on the basis of jaw relaxation, position of vocal cords and diaphragmatic response. Neuromuscular transmission was assessed at the adductor pollicis muscle using a TOF-GUARD monitor. Excellent and good intubating conditions were obtained in 100% of patients in the ketamine group and in 50% of patients in the thiopentone group (p = 0.002). Jaw relaxation was similar in both groups but vocal cord conditions were better and the diaphragmatic response less marked in the ketamine group compared with the thiopentone group (p = 0.002). The degree of neuromuscular block [% decrease of T1, mean (SD)] at the time of intubation was similar: 51.8 (25)% (ketamine group) and 54.3 (23.1)% (thiopentone group). We conclude that ketamine 2.5 mg.kg-1 provides better intubating conditions than thiopentone 5 mg.kg-1 1 min after administration of rocuronium 0.6 mg.kg-1.     

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.     

Rocuronium combined with i.v. lidocaine for rapid tracheal intubation

BACKGROUND: Rocuronium (ORG 9426) has been shown to have an onset of action more rapid than other nondepolarizing neuromuscular blocking agents and to provide intubating conditions similar to those of succinylcholine 60-90 s after administration. We compared the intubating conditions and hemodynamic changes after the administration of rocuronium 0.6 mg kg(-1) and lidocaine 1.5 mg kg(-1) with rocuronium alone and succinylcholine 60 and 90 s after administration. METHODS: One hundred and twenty-five adult patients of ASA physical status I or II scheduled for elective surgery were randomly divided into five groups. After propofol administration in all patients, patients in group Su (succinylcholine), group R60 (rocuronium) and group RL60 (rocuronium-lidocaine) were intubated within 60 s, while groups RL90 and R90 were intubated 90 s after the administration of rocuronium and succinylcholine. Laryngoscopy was performed and intubating conditions were graded by an experienced anesthetist blind to the muscle relaxant allocation. RESULTS: In this study, groups Su, RL60, R90 and RL90 had similar intubation scores, which were significantly better than that for group R60. Heart rate did not increase after intubation in groups Su, RL60 and RL90. CONCLUSION: The combination of lidocaine (1.5 mg kg(-1)) and low-dose rocuronium (0.6 mg kg(-1)) along with propofol is clinically equivalent to succinylcholine, improves intubating conditions in 60 s and effectively blocks increases in heart rate after intubation.     

Thiopental--ketamine association and low dose priming with rocuronium for rapid sequence in duction of anaesthesia for elective cesareum section

Obstetric patients undergoing caesarean section under general anaesthesia require rapid induction due to high risk of aspiration. Rocuronium provides the shortest onset of action of nondepolarizing blocking agents. Onset time can be shortened by the priming principle. Ketamine has been shown to improve intubating conditions when used in association with rocuronium. Even if ketamine crosses the placenta rapidly, it does not produce neonatal depression unless used in doses above 1-1.5 mg x kg(-1). We present a case of elective caesarean section due to pelvic disproportion managed in general anaesthesia. Following 5 min of preoxygenation, a priming dose of 0.04 mg x kg(-1) of rocuronium was administered. The patient was maintained on spontaneous breathing with 100% oxygen by face mask for 3 min and then induced in rapid sequence with thiopental 2 mg x kg(-1), ketamine 1 mg x kg(-1) and 0.4 mg x kg(-1) or rocuronium. Intubation was performed 30 s after induction (twitch tension 17%) with an excellent clinical intubating score. No adverse events such as muscle weakness or patient discomfort were observed or reported by the patient. Time from injection of the intubating does of rocuronium to recovery of 25% of single twitch was 26 min. Recovery index (T25-75) was, instead, of 3 min and 25 s. The combination of the induction agents thiopental and ketamine, associated with low dose priming with rocuronium, have guaranteed excellent intubating conditions in this clinical context.     

The intubating laryngeal mask airway: rocuronium improves endotracheal intubating conditions and success rate

STUDY OBJECTIVE: To assess intubating conditions without neuromuscular blocking drugs, to determine the relation between the dose of rocuronium and the probability of achieving excellent or at least good (good or excellent) intubating conditions with the intubating laryngeal mask airway (ILMA), and finally, to determine the relationship between rocuronium use and the success rate of endotracheal intubation. DESIGN: Prospective, randomized, double-blinded, placebo-controlled study. SETTING: University-affiliated medical center. PATIENTS: Sixty American Society of Anesthesiologists physical status I and II patients undergoing elective surgery. INTERVENTIONS: Anesthesia was induced with propofol 2.5 mg/kg and fentanyl 1 microg/kg. One minute after loss of consciousness, patients received rocuronium 0.2 mg/kg or saline. In the rocuronium group, if intubating conditions were scored as poor, rocuronium dose in the next patient was increased by 0.05 mg/kg. If intubating conditions were scored as good, no change was made, but if conditions were scored as excellent, the dose was decreased by 0.05 mg/kg. One minute after rocuronium or saline administration, an ILMA was used to intubate the trachea. If intubation was unsuccessful, a second attempt was made using the ILMA. MEASUREMENTS: We recorded intubating conditions and the success rate of tracheal intubation. MAIN RESULTS: Without rocuronium, the probability of achieving at least good intubating conditions with the ILMA was 30%. A rocuronium dose of 0.2 mg/kg resulted in a probability of 80% to achieve at least good intubating conditions. Rocuronium significantly increased the success rate of the second intubation attempt. CONCLUSION: To achieve good or excellent intubating conditions with the ILMA, a rocuronium dose lower than the standard intubating dose of 0.6 mg/kg can be used. Neuromuscular blockade increases the success rate of intubation if a second attempt is necessary.     

Comparison of rocuronium and suxamethonium for use during rapid sequence induction of anaesthesia

This study was designed to compare the tracheal intubating conditions during a rapid sequence induction of anaesthesia using rocuronium 0.6 ( n  = 61) or 1.0 mg.kg⁻¹ ( n  = 130) or suxamethonium 1.0 mg.kg⁻¹ ( n  = 127) as the neuromuscular blocking drugs. Anaesthesia was induced with fentanyl 1–2 μg.kg⁻¹ and thiopentone 5 mg.kg⁻¹ (median dose) and intubating conditions were assessed 60 s after the administration of the neuromuscular blocking drug by an observer unaware of which drug had been given. Intubating conditions were graded on a three-point scale as excellent, good or poor, the first two being considered clinically acceptable. The study was carried out in two parts. At the end of the first part a comparison between the two doses of rocuronium was carried out when at least 50 patients had been enrolled in each group. The results showed the intubating conditions to be significantly superior with the 1.0 mg.kg⁻¹ dose of rocuronium (p < 0.01). Final comparison between the 1.0 mg.kg⁻¹ doses of rocuronium and suxamethonium showed no significant difference in the incidence of acceptable intubations (96 and 97%, respectively). The incidence of excellent grade of intubations was, however, significantly higher with suxamethonium (80% vs. 65%; p = 0.02). It is concluded that rocuronium 1.0 mg.kg⁻¹ can be used as an alternative to suxamethonium 1.0 mg.kg⁻¹ as part of a rapid sequence induction provided there is no anticipated difficulty in intubation. The clinical duration of this dose of rocuronium is, however, 50–60 min.     

Rocuronium zur elektiven Narkoseeinleitung Verlauf der neuromuskulären Blockade und Intubationsbedingungen nach 2facher ED95 (0,6 mg/kg) und nach Dosisreduktion (0,4 mg/kg)

BACKGROUND: Rocuronium is a non-depolarising neuromuscular blocking agent structurally related to vecuronium. The compound has a rapid onset and an intermediate duration of action. The rapid onset is of importance in patients at risk for pulmonary aspiration, for elective induction of anaesthesia slower onset properties generally are accepted. In this context, we asked whether the induction dose of rocuronium may be reduced to doses smaller than 2 x ED95 in situations in which slower onset properties may be acceptable. METHODS: The time course of neuromuscular block and intubating conditions of two different doses rocuronium, 2 x ED95 (0.6 mg/kg) and 1.3 x ED95 (0.4 mg/kg), were investigated in 90 patients. We first determined the time course of neuromuscular block using electromyography (EMG), n = 15 for each group. In the second part the intubating conditions 3 min after injection of either rocuronium 0.6 mg/kg or rocuronium 0.4 mg/kg were evaluated, n = 30 for each group. RESULTS: In the present study reduction of the dose of rocuronium led to a slower onset (148 +/- 32 s vs. 220 +/- 30 s; P < 0.05) and a shorter clinical duration (21 min +/- 4 vs. 36 +/- 7 min; P < 0.05). The recovery index was modified by the dose reduction: 11 +/- 3 min after 0.6 mg/kg rocuronium and 9 +/- 2 min after 0.4 mg/kg. After both doses of rocuronium the intubating conditions were good to excellent, no difference between both rocuronium groups were found. CONCLUSION: In the present study dose reduction from 0.6 mg/kg rocuronium to 0.4 mg/kg rocuronium led to a slower onset and reduced clinical duration. However, the intubating conditions, evaluated 3 min after injection of the muscle relaxant were comparable. This offers new possibilities for muscle relaxation for surgical or diagnostic procedures of short duration and may reduce costs.     

The use of low-dose rocuronium to facilitate laryngeal mask airway insertion

In this two-phase study, the efficacy of low-dose rocuronium to facilitate laryngeal mask airway (LMA) insertion was evaluated. First, the onset time of 100, 150 and 300 micrograms.kg-1 rocuronium was determined using mechanomyography in three groups of patients (n = 10 in each) anaesthetized with propofol-fentanyl-nitrous oxide. In the second part, 100, 150 or 300 micrograms.kg-1 rocuronium or placebo was administered randomly to four groups of patients (n = 50 in each) in a double-blind manner. Following this, anaesthesia was induced with propofol 2.5 mg.kg-1. Patients in the group of 300 micrograms.kg-1 rocuronium or placebo received propofol after 1.5 min. Patients in the group of 100 or 150 micrograms.kg-1 rocuronium received propofol after 3 min. The LMA was inserted 90 sec later. Immediately before the induction of anaesthesia, patients were questioned about the symptoms of neuromuscular block. In phase 1, onset times were 180 sec (SD 41), 191 sec (59) and 89 sec (34), respectively. In phase 2, insertion of the LMA was graded as easy in 90.6% of patients receiving rocuronium, compared with 42% of patients who had only propofol (P < 0.05). Rocuronium improved the overall ease of LMA insertion. LMA insertion was graded easy in 80% of patients who received 100 micrograms.kg-1 rocuronium. The incidence of unpleasant effects was greatest with 300 micrograms.kg-1 rocuronium. The optimal dose needed to facilitate LMA insertion with minimal unpleasant effects appeared to be 100 micrograms.kg-1 rocuronium.