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 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.     

不同静脉注射速度对小儿罗库溴铵注射痛反应的影响

目的 观察静脉注射速度对小儿罗库溴铵静脉注射痛反应的影响.方法 全麻下择期手术患儿60例均分为两组,给予咪唑安定、氯胺酮,入睡后给予罗库溴铵0.6 mg/kg(浓度10mg/ml).A组注速≤3 s,B组注速60 s.采用加速度肌松监测仪监测肌松指标,观察罗库溴铵静脉注射痛反应、气管插管条件和肌松起效时间.结果 B组静脉注射痛反应的发生率明显低于A组(P<0.01);两组插管条件和肌松起效时间的差异无统计学意义.结论 缓慢静脉注射罗库溴铵能明显减轻罗库溴铵静脉注射痛,对气管插管条件和肌松起效时间无明显影响.     

Einfluss des Geschlechts auf die Intubationsbedingungen nach Rocuronium

PURPOSE: There is increasing evidence for gender differences in the pharmacokinetics and pharmacodynamics of anaesthetic drugs and neuromuscular blocking agents, e.g. rocuronium (Roc). Females require 30% less Roc than males to achieve the same degree of neuromuscular block and onset times are shorter. However, whether this leads to an improvement of the intubation conditions in females is unclear. METHODS: After approval of the ethics committee 60 female and 60 male patients were each randomised into 2 groups to receive 0.6 mg/kg body weight Roc or 1.0 mg/kg succinylcholine (Sux; control group). Induction: thiopentone (5 mg/kg), fentanyl (3 microg/kg) then Roc (Roc groups) or Sux (Sux groups) and tracheal intubation after 60 s. Time to intubation, glottic exposure and intubating conditions were assessed. RESULTS: Men were significantly larger and heavier (p<0.001) than women, but the body mass index was comparable (ns). Number of attempts, time to intubation, and Cormack grades were comparable (ns). However, the rate of clinically acceptable intubation conditions was significantly higher in the female compared to the male Roc group: 80% vs 47%, p<0.05. The incidence of clinically acceptable intubation conditions in the female Roc and Sux groups were similar (80%). CONCLUSION: The intubation conditions after Roc were significantly better in women than in men. The differences were Roc-related and did not occur in the control groups.     

A randomised controlled trial comparing rocuronium priming, magnesium pre-treatment and a combination of the two methods

We investigated whether magnesium sulphate combined with rocuronium priming shortens the onset of neuromuscular blockade, compared with these methods used alone. Ninety‐two patients scheduled for general anaesthesia were randomly allocated to one of four groups: controls were given 0.6 mg.kg^?1 rocuronium; patients in the prime group were given 0.06 mg.kg^?1 rocuronium three minutes before a further dose of 0.54 mg.kg^?1 rocuronium; patients in the magnesium group were given an infusion of 50 mg.kg^?1 magnesium sulphate before rocuronium and patients in the magnesium and prime group were given both the magnesium sulphate and the priming dose of rocuronium. Tracheal intubation was attempted 40 s after the rocuronium injection. The time to onset of neuromuscular blockade was the primary outcome; duration of blockade and tracheal intubating conditions were also measured. The group allocation and study drugs were coded and concealed until statistical analyses were completed. The magnesium and prime group had the shortest mean (SD) onset time (55 (16) s; p < 0.001), and best tracheal intubating conditions (p < 0.05). No statistical difference was found for the duration of blockade. As for adverse events, a burning or heat sensation was reported in eight (35%) and six (26%) patients in the magnesium and magnesium and prime groups, respectively. The combination of magnesium sulphate and rocuronium priming accelerated the onset or neuromuscular blockade and improved rapid‐sequence intubating conditions, compared with either magnesium sulphate or priming used alone.     

Comparison of different priming techniques on the onset time and intubating conditions of rocuronium

BACKGROUND AND OBJECTIVE: The aim was to compare the effects of two different priming doses and priming intervals with the standard intubating dose of rocuronium on the onset time and intubation conditions. METHODS: After induction of anaesthesia, 75 patients were randomly assigned to one of five groups. Patients in Group 1 received a priming dose of rocuronium 0.06 mg kg(-1) followed 2 min later by rocuronium 0.54 mg kg(-1), Group 2 received a priming dose of 0.10 mg kg(-1) followed 2 min later by a rocuronium injection of 0.50 mg kg(-1). Group 3 was given a priming dose of 0.06 mg kg(-1) followed 3 min later by administration 0.54 mg kg(-1), where Group 4 received a priming dose of 0.10 mg kg(-1) followed 3 min later by injection of 0.50 mg kg(-1). Group 5 received a placebo injection followed 3 min later by rocuronium 0.60 mg kg(-1). RESULTS: Priming with a 3 min priming interval shortened the onset time of rocuronium irrespective of the dosage of (P < 0.001). Clinical duration of action was significantly longer after priming in Group 4 than in Group 5. Clinically acceptable intubation conditions were obtained in all patients. CONCLUSIONS: Priming with a 3 min priming interval was effective when rapid tracheal intubation with rocuronium was necessary. However, priming with rocuronium should be used carefully with special attention given to the possibility of hypoxia and aspiration of gastric contents in awake patients.     

Different priming techniques,including mivacurium,accelerate the onset of rocuronium

Different priming sequences of equipotent doses of rocuronium and mivacurium on the onset of maximum neuromuscular block and intubating conditions were compared with those obtained after succinylcholine. During thiopentone-fentanylnitrous oxide anaesthesia, 70 patients were randomly assigned into seven groups. Group I received mivacurium 0.15 mg · kg^?1 as a single bolus dose. Group II received a priming dose of mivacurium 0.015 mg · kg^?1 followed three minutes later by mivacurium 0.135 mg · kg^?1. Group III received rocuronium 0.6 mg · kg^?1 as a single bolus dose, and Group IV received an initial dose of rocuronium 0.06 mg · kg^?1 followed by rocuronium 0.54 mg · kg^?1. Group V received a priming dose of mivacurium 0.015 mg · kg^?1 followed by rocuronium 0.54 mg · kg^?1. Group VI received an initial dose of rocuronium 0.06 mg · kg^?1 followed by mivacurium 0.135 mg · kg^?1. Group VII received succinykholine 1.0 mg · kg^?1. Groups I, III, and VII received a placebo injection before the administration of the neuromuscular blocking drug. Additional thiopentone 2 mg · kg^?1 iv was given 30 sec before intubation. Onset times (mean (95% confidence interval)) after priming a rocuronium block with either rocuronium (73 (57–90) sec) or mivacurium (58 (47–69) sec) were similar to those after succinykholine (54 (40–68) sec), and were shorter (P < 0.01) than that observed in other groups. Intubating conditions were not different between the groups. The duration of neuromuscular block was shortest with succinykholine. It is concluded that priming a rocuronium block with either mivacurium or rocuronium resulted in a neuromuscular block comparable to that of succinykholine in both the onset of action and intubating conditions.     

Rocuronium versus vecuronium during fentanyl induction in patients undergoing coronary artery surgery.

OBJECTIVE: To evaluate the neuromuscular, ventilatory, and cardiovascular effects of rocuronium and vecuronium. DESIGN: Randomized, prospective, blinded study. SETTING: Tertiary care teaching center, single institution. PARTICIPANTS: Patients undergoing elective coronary artery bypass graft procedure. INTERVENTIONS: Patients received rocuronium, 1.0 mg/kg (n = 17), or vecuronium, 0.15 mg/kg (n = 15), during fentanyl induction of anesthesia. MEASUREMENTS AND MAIN RESULTS: Measures consisted of time to visual loss of orbicularis oculi twitches in response to facial nerve stimulation, ease of mask ventilation, hemodynamics, need for vasoactive drugs, and tracheal intubating conditions. Median time to twitch loss was faster (p < 0.05) after rocuronium (60 s) than after vecuronium (>84 s). Within 45 seconds, only 3 of 17 patients in the rocuronium group had moderate-to-severe difficulty with mask ventilation versus 12 of 15 patients in the vecuronium group (p < 0.05). Tracheal intubating conditions were excellent in all patients after rocuronium. In the vecuronium group, intubating conditions were excellent in 46%, good in 27%, and poor in 27% (p < 0.05 vrocuronium). Patients receiving vecuronium were more likely to require ephedrine and phenylephrine for hypotension (10/15 patients v 5/17 patients for rocuronium, p < 0.05). There were no clinically important differences in hemodynamic variables, oxygen metabolism, or myocardial ischemia between groups. CONCLUSION: During narcotic induction of anesthesia, rocuronium was associated with lower requirement for vasopressors, faster onset of neuromuscular blockade, and better conditions for mask ventilation and tracheal intubation compared with vecuronium.     

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.     

Effects of ephedrine on intubating conditions following priming with rocuronium

BACKGROUND: Onset of action of muscle relaxants is influenced by cardiac output and muscle blood flow. Ephedrine reduces the onset time of rocuronium. Onset is also shortened by priming. Accordingly, we hypothesized that priming combined with ephedrine is superior to either technique used separately. METHODS: Four groups of randomly allocated patients (n = 31), ASA I - II, were induced with propofol 2.5 mg kg(-1). In groups I and II, 0.04 mg kg(-1) of rocuronium was followed by a 3-min priming interval. Induction was followed by an intubation dose of 0.04 mg kg(-1). Then a 30-s intubation was attempted. In groups III and IV the same sequence was repeated except for sham priming and an intubation dose of 0.44 mg kg(-1). In groups I and II, ephedrine (210 microg kg(-1)) was injected before propofol. In groups II and V, an equivalent volume of normal saline was injected. Jaw relaxation, vocal cord position, and diaphragmatic response were used to assess intubating conditions. RESULTS: All patients of group I were intubated 30 s after the intubating dose and within a 20-s interval compared with 74% of patients in groups II and III, and 84% of patients in group IV. Intubating conditions were graded good to excellent in all patients in group I compared with 42% of those in group II, 35% in group III and 52% in group IV (P < 0.01 vs. group I). During the priming interval, no adverse effects were observed or reported. CONCLUSIONS: Ephedrine in combination with propofol significantly improved clinical intubating conditions at 30 s following priming with rocuronium compared with priming with ephedrine without priming.     

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.     

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.     

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.     

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.     

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.     

Priming with atracurium: improving intubating conditions with additional doses of thiopental

The effects of different intubating doses of atracurium on the time of onset, and the effect of an additional dose of thiopental on intubating conditions, were studied in 72 patients divided into six groups (n = 12 in each). Stratified sampling was used to obtain an even sex distribution. Groups I, III, and V (controls) received atracurium as a single bolus dose of 0.4, 0.5 or 0.6 mg/kg respectively. Groups II, IV, and VI received an initial (priming) dose of 0.05 mg/kg followed 3 min later by 0.35, 0.45, or 0.55 mg/kg respectively. The time of onset, that is the time from the intubating dose to complete suppression of the train-of-four (TOF) response, was significantly accelerated after administration of atracurium in divided doses. Increasing the intubating dose of atracurium after an initial 0.05 mg/kg from 0.35 to 0.55 mg/kg did not result in further significant acceleration of the onset time, but resulted in prolongation of the duration of neuromuscular blockade. When divided doses of atracurium were given, administration of 2 mg/kg thiopental (in addition to the 5 mg/kg used for induction) before the injection of the intubating dose resulted in improvement of intubating conditions as reflected by statistically significant changes in intubating scores. This result was probably due to the increase by thiopental in the depth of anesthesia. Therefore, when thiopental is given as supplement, the priming technique can be made to provide better conditions for tracheal intubation in less than 90 sec.     

Priming with vecuronium and atracurium--a comparison

Vecuronium (V) and atracurium (A) were compared in a randomised study in premedicated patients undergoing laparoscopy for gynecological pathology. Both groups contained ten patients. Anesthesia was induced with fentanyl (0.1 mg) and thiopentone (1 mg/kg initially and subsequently 4 mg/kg). A priming dose of vecuronium (20 micrograms/kg) or atracurium (100 micrograms/kg) was given one minute before the intubating dose (60 micrograms/kg for vecuronium and 300 micrograms/kg for atracurium). Ninety seconds thereafter intubation was performed. Maintenance of anesthesia consisted of isoflurane at an inspiratory concentration of 1% in a mixture of O2/N2O (50%/50%) with small supplements of fentanyl. Neuromuscular block was monitored with the Datex Relaxograph. Results show that neither drug offers major clinical advantages over the other: there is no difference in speed of onset (V:T190sec 14.6 +/- 4.3%; A:T190sec 23.5 +/- 6.5%; Mean +/- SEM) and duration of neuromuscular block (V:T150sec 34.2 +/- 3.5 min; A:T150sec 41.3 +/- 2.8 min; Mean +/- SEM) and intubation conditions are almost identical.     

Intubationsbedingungen und Verlauf der neuromuskulären Blockade nach Rocuronium bei endoskopischen Operationen in der HNO-Heilkunde

Rocuronium is a new nondepolarizing muscle relaxant for which a fast onset has been described. The goal of this study was to examine whether the characteristics of rocuronium could make it an appropriate relaxant for the anaesthetic management of operations of intermediate duration such as endoscopic upper airway surgery. These operations, which require the anaesthesiologist and surgeon to ”share” the patient’s airway, require good muscle relaxation for endotracheal intubation and placement of endoscopic instruments. In addition, the time course of neuromuscular blockade and its relation to the quality of intubating conditions were analysed. Methods: The study was approved by the local ethics committee; 30 patients (ASA status 1–3) scheduled for elective endoscopic upper airway surgery were included after written informed consent. Exclusion criteria were suspected difficult intubating conditions, neuromuscular disease, or antibiotic therapy with aminoglycosides during the last 24?h. Anaesthesia was induced by propofol 2?mg/kg and alfentanil 1?mg after volume loading with 500?ml Ringer’s lactate and preoxygenation, and was maintained by propofol infusion 5–8?mg/kg/h and repetitive alfentanil injections according to clinical needs. Endotracheal intubation was performed by a senior anaesthesiologist 90?s after injection of rocuronium 0.6?mg/kg (2×ED₉₅). Intubating conditions were graded 1 to 4 (1=excellent, 2=good, 3=sufficient, 4=inadequate). Acceleromyography was used for neuromuscular monitoring by means of the TOF-guard (Organon Teknika/Biometer). The adduction movement of the thumb was measured by an acceleration transducer while stimulating the ulnar nerve at the wrist via surface electrodes in a supramaximal train-of-four (TOF) mode (2?Hz every 15?s). Twitch height and TOF ratio were documented during the course of neuromuscular blockade. Data are presented as mean±standard deviation. Results: Patients were aged 37 to 64 years (mean 54±7). Intubating conditions were excellent in 17 cases and good in 7. In 2 cases intubating conditions were graded sufficient, as patients could be easily intubated but showed clear diaphragmatic movements at intubation. In 4 patients intubating conditions could not be judged, as a laryngoscopic view of the glottic structures was impossible for anatomic reasons. Neuromuscular block at intubation was 78±22%, onset time 152±62?s, clinical duration 30±8?min, and recovery index 11±4?min. The TOF ratio required 51±14?min to return to 0.7. Conclusions: Good to excellent intubating conditions can be expected 90?s after injection of rocuronium 0.6?mg/kg. Diaphragmatic reactions cannot be excluded. Complete relaxation of the adductor pollicis muscle is not necessary for endotracheal intubation. Intubation at a certain time interval, for example, 90?s after injection of rocuronium 0.6?mg/kg, can be recommended. Onset and recovery characteristics of rocuronium make it an appropriate relaxant for the anaesthetic management of operations of intermediate duration such as endoscopic upper airway surgery. Care should be given, however, to detect inadequate recovery of neuromuscular transmission, as there are considerable interindividual differences in recovery.     

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 or vecuronium when the timing of intubation is judged by clinical criteria

The onset of action and intubating conditions after rocuronium 0.6 mg kg-1 or vecuronium 0.1 mg kg-1 were compared in a randomized, double- blind study when the timing of tracheal intubation was determined by clinical judgment alone. Times to laryngoscopy and completion of intubation were mean 89 (SD 20) s and 119 (28) s, respectively, in the rocuronium group compared with 110 (26) s and 142 (32) s in the vecuronium group (P < 0.05 in both cases). Recuronium also resulted in significantly better intubating conditions compared with vecuronium but with no significant reduction in the haemodynamic response to intubation. We found that onset of satisfactory intubating conditions after rocuronium was detected clinically, although even earlier intubation should be possible by careful timing or by neuromuscular monitoring.