The agreement between adductor pollicis mechanomyogram and first dorsal interosseous electromyogram

The agreement between evoked adductor pollicis mechanomyogram and first dorsal interosseous evoked electromyogram (EMG) was evaluated during a pharmacodynamic study of rocuronium and vecuronium. In the first place the effective doses of rocuronium producing 50% and 90% block (ED₅₀ and ED₉₀, respectively) were established in 32 neurolept anaesthetized patients from the adductor pollicis mechanomyogram and the first dorsal interosseous EMG area and amplitude. Secondly, limits of agreement between the two methods were evaluated from the mean difference between methods 2 s.d. in 20 patients during onset of block following 2 × ED₉₀ of rocuronium and vecuronium, and during recovery from the last supplementary dose of 1/2 × ED₉₀. Limits of agreement show how much the EMG may be above or below the mechanomyogram. No differences were found between mechanomyographical and EMG based ED₅₀ (0.20 mg kg^-1) and ED₉₀ (0.30–0.32 mg kg^-1), respectively. The first EMG train–of–four (TOF) response overestimated block at 25% recovery and underestimated block at 75% and 90% recovery by only 3–7%. Limits of agreement suggested that the EMG may be 7–8% above or below the mechanomyogram during onset compared to 12–17% during recovery. The EMG TOF ratio lagged behind that of the mechanomyogram by 0.05 at TOF ratios below 0.50. No difference was found between methods at a TOF ratio of 0.75. Limits of agreement indicated that the EMG TOF ratio may be 0.12–0.15 above or below that of the mechanomyogram. Agreement between the amplitude and the area of the EMG were better than between the mechanomyogram and the EMG. Evaluation of the time courses of action showed that rocuronium had a faster onset of action than vecuronium (1.8 min compared to 2.8 min) while duration of action and reversal were similar. In conclusion, the first dorsal interosseous EMG amplitude and area can be used to assess rocuronium and vecuronium block.     

Neuromuscular effects of 600 μg·kg−1 of rocuronium in infants during nitrous oxide-halothane anaesthesia

Rocuronium bromide (Zemuron) is a new steroidal nondepolarizing neuromuscular blocking drug. We were interested in determining the effect of a bolus of rocuronium in infants during halothane anaesthesia as we did previously in older children. Eighteen infants (2-11 months) received a bolus of 600 μg·kg^?1, which is equal to twice the dose of rocuronium estimated to produce 95% depression of neuromuscular function (ED₉₅) in children (2-12 yr). Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation of the ulnar nerve at 2 Hz for 2 s at 10-s intervals. Time (mean ± SEM, range) from administration of 600 μg·kg^?1 rocuronium to 90% (B₉₀) and 100% (B₁₀₀) neuromuscular block was 37 ± 2 (20-60) s and 64 ± 10 (20-180) s, respectively. The time to recovery of neuromuscular transmission to 10% (T₁₀) was 35.3 ± 3.0 (20.7-57.8) min and to 25% of baseline (T₂₅) was 41.9 ± 3.2 (24.3-67.7) min. The recovery index (T₂₅-T₇₅) was 26.6 ± 2.7 (11.7-44.5) min, and the time to recovery of the train-of-four ratio (T₄/T₁) ± 0.75 was 82.1 ± 6.9 (53.2-138.3) min. The plasma concentration of rocuronium when T₁ had recovered to about 30% was 654 ± 34 (417-852) ng·ml^?1 which is similar to that observed in children. Six-hundred μg·kg^?1 of rocuronium has a rapid onset of effect in infants and prolonged duration of action in infants compared to children.     

The pharmacodynamics of rocuronium in pediatric patients anesthetized with halothane

The aim of this study was to determine the neuromuscular blocking potency of rocuronium (ORG 9426) in 4-to 14-year old children anesthetized with halothane. After induction of anesthesia, the ulnar nerve was stimulated with electrical impulses of 0.2 ms duration every 12 s and the force of contraction of the thumb (P) was continuously recorded. Doses of 0.12, 0.16, 0.20, and 0.24 mg·kg⁻¹ rocuronium were administered, in a randomized fashion, to 4 groups of 12 patients each. The ED₅₀, ED₉₀, and ED₉₅ of rocuronium determined from the log dose-probit regression lines were 0.18, 0.34, and 0.40 mg·kg⁻¹, respectively. To facilitate tracheal intubation, after the development of the maximal effect of the first dose, a variable second dose of rocuronium was administered to increase the total dose to 0.3 mg·kg⁻¹. If after the second dose P was greater than 10% of control, additional 0.025–0.1 mg·kg⁻¹ increments of rocuronium were administered until P became less than 10% of control. At this time the trachea was intubated. Muscular relaxation was maintained with 0.075, 0.1, or 0.125 mg·kg⁻¹ rocuronium, administered whenever P recovered to 25% of control. The clinical duration of these doses was 6.9±2.8, 6.1±0.4, and 8.1±0.6 min, respectively. On repeated administration of three 0.1 or 0.125 mg·kg⁻¹ doses, rocuronium showed little cumulative tendency. Time for spontaneous recovery of P from 25% to 75%, 8.4±0.39 min and from 10% to 90%, 16.19±0.15 min, of control, were relatively short. When at termination of anesthesia T4/T1 ratios were lower than 0.75, the residual neuromuscular block could be antagonized with 0.5 mg·kg⁻¹ edrophonium in 2 min. Rocuronium, 0.3 mg·kg⁻¹ caused a 13.5% increase of heart rate but had no effect on blood pressure. In conclusion, in 4 to 14-year-old children, rocuronium appears to have a more rapid onset and shorter duration of action than other steroid-type muscle relaxants. Presented in part at the Annual Meeting of the American Society of Anesthesiologists, San Francisco, October, 1991     

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.     

Comparison of neuromuscular effects, efficacy and safety of rocuronium and atracurium in ambulatory anaesthesia

Purpose

To compare the neuromuscular effects, efficacy, and safety of equi-effective doses of rocuronium and atracurium in ambulatory female patients undergoing surgery.

Methods

Forty-one patients undergoing laparoscopic gynaecological surgery were randomized to receive 2 × ED₉₀ rocuronium (0.6 mg·kg^?1; n = 20) or atracurium (0.5 mg·kg^?1; n = 21) during intravenous propofol/alfentanil anaesthesia with N₂O/O₂ ventilation. Neuromuscular block was measured with a mechanomyogram eliciting a train-of-four (TOF) response at the wrist. Intubation conditions 60 sec after administration of muscle relaxant and immediate cardiovascular disturbances or adverse events during the hospital stay were noted by blinded observers.

Results

Compared with atracurium, rocuronium was associated with a shorter onset time (59.0 ± 22.2vs 98.6 ± 41.4 sec;P < 0.001) and clinical duration of action (33.3 ± 7.1vs 44.7 ± 7.2 min;P < 0.001), but longer spontaneous recovery index (9.6 ± 2.41vs 6.9 ± 1.89 min;P = 0.023) and a similar time to spontaneous recovery to TOF 70%; 53 ± 6.31vs 59.2 ± 7.59 min;P =0.139). Tracheal intubation was accomplished in < 90 sec in all patients receiving rocuronium but in only 14 of 21 patients receiving atracurium. The incidence of adverse events and the cardiovascular profiles for the two drugs were similar, although one patient receiving atracurium experienced transient flushing of the head and neck.

Conclusion

Rocuronium has minimal side effects, provides conditions more suitable for rapid tracheal intubation, and is associated with a shorter clinical duration than atracurium. Once begun, the spontaneous recovery profile of rocuronium is slightly slower than that of atracurium.     

Comparison of rocuronium and vecuronium in paediatric cardiac surgery, using sevoflurane anaesthesia

Aim. The goal was to study the haemodynamic effects and intubating conditions, of rocuronium, vs. vecuronium in paediatric patients undergoing elective cardiac surgery. The haemodymanic effects and intubating conditions, of rocuronium, in children undergoing cardiac surgery, remain incompletely characterised. Methods. A double blind randomised study was conducted in 40 children with congenital heart disease, undergoing open heart surgery. Patients were divided into 2 groups — Group A received rocuronium (0.9 mgkg⁻¹) and Group B, vecuronium (0.2 mgkg⁻¹) (n=20 in each group) Intubating conditions and haemodynamic profile were assessed at 60 seconds and at 90 seconds. Neuromuscular monitoring was established before muscle relaxant administration. Anaesthesia technique standardised with sevoflurane 7–8% in addition, was used in both groups. Results. Compared with vecuronium, rocuronium was associated with shorter onset time (60.2±20.2 vs 88.6±41.2 secs; P<0.001) and clinical duration of action (34.3±8.4 vs 44.7±6.2 min, P<0.001). According to standardised, intubation scores, intubation conditions, at 90 seconds in Group A was 90% and Group B 80%. However at 60 seconds they were 80% and 40% respectively. Haemodynamic stability in both the groups was similar, although one patient in Group B showed transient bradycardia and hypotension. Conclusion. Rocuronium showed better intubating conditions than vecuronium at 60 seconds in paediatric patients undergoing open heart surgery.     

Rocuronium and sugammadex for rapid sequence induction of obstetric general anaesthesia

Background: Many anaesthetists use rocuronium in place of suxamethonium for rapid sequence induction (RSI). This is less common in obstetric anaesthesia as the duration of action of an effective dose of rocuronium exceeds most obstetric procedures. Sugammadex offers the possibility of rapidly reversing profound rocuronium neuromuscular blockade at the end of surgery. We aimed to determine whether rocuronium 1.2 mg/kg used for RSI in the obstetric population would provide good intubating conditions at 60 s and would be effectively reversed by sugammadex at the end of surgery. Methods: We present a prospective series of 18 patients who received rocuronium 1.2 mg/kg at induction of anaesthesia, monitored with a train‐of‐four ratio (TOF)‐Watch SX^®, and reversed using sugammadex 4 mg/kg. Results: The mean (95% CI) onset time of rocuronium was 71 (56–86) s, and the mean (95% CI) time to recovery of the TOF to ≥90%, after the administration of sugammadex 4 mg/kg at the end of surgery, was 86 (69–104) s. Conclusion: Rocuronium 1.2 mg/kg reversed by sugammadex appears to be effective in the obstetric population.     

The prolonged duration of rocuronium in Chinese patients

We compared the potency and duration of action of rocuronium in Chinese and Caucasian patients during general anesthesia. Thirty-six women (18 Caucasian and 18 Chinese) and 36 children (18 Caucasian and 18 Chinese) were evaluated during the administration of propofol/fentanyl anesthesia. Patients in each age group were randomized into three subgroups to receive single doses of 0.06, 0. 12, or 0.18 mg/kg rocuronium (adults) or 0.12, 0.18, or 0.24 mg/kg rocuronium (children). Neuromuscular blockade was assessed by electromyography of the adductor pollicis after train-of-four (TOF) stimulation of the ulnar nerve. Dose response curves were constructed when maximum neuromuscular depression of the first twitch of the train (T(1)) was obtained. A second bolus dose of rocuronium was then administered to a total dose of 0.6 mg/kg. The times of spontaneous recovery to T(1) 10%, 25%, and 90% of control and to TOF 0.25, 0.50, and 0.70 were recorded. For both adults and children, recovery occurred later in Chinese than in Caucasian patients (P<0.05 for T(1) of 10%, 25%, 75%, and 90% and TOF to 0.7). The 50% effective dose was smaller in Chinese adults (125+/-63 vs. 159+/-66 microg/kg) and Chinese children (171+/-43 vs. 191+/-46 microg/kg) than in Caucasian adults and children, but the difference was not statistically significant. In adults, time to 25% T(1) recovery was 43+/-13 min in Chinese patients and 33+/-10 min in Caucasian patients (P<0.05). The corresponding values were more rapid for children: 30+/-10 and 24+/-6 min (P<0.05). We conclude that the recovery from rocuronium neuromuscular blockade was longer in Chinese compared with Caucasian patients and in adults compared with children.     

Potency and time course of action of rocuronium during desflurane and isoflurane anaesthesia

We have studied the potency and onset and duration of action of rocuronium in patients anaesthetized with 1 MAC of desflurane or isoflurane (in 66% nitrous oxide). Potency was estimated using the single bolus dose technique. Neuromuscular block was measured by stimulation of the ulnar nerve and recording the force of contraction of the adductor pollicis muscle. The ED50 and ED95 of rocuronium were estimated as 138 (95% confidence limits 117-162) micrograms kg-1 and 281 (241-328) micrograms kg-1, and 126 (105-151) micrograms kg-1 and 283 (236-339) micrograms kg-1 during desflurane and isoflurane anaesthesia, respectively. The mean times to onset of maximum block after rocuronium 0.6 mg kg-1 were 1.0 (SD 0.10) min and 1.1 (0.15) min, respectively, during anaesthesia with desflurane and isoflurane. The respective times to recovery of T1 (the first response in the train-of- four (TOF) stimulation) to 25% and 90% were 36 (8.3) min and 54 (15.4) min during desflurane anaesthesia and 31 (8.2) min and 45 (12.7) min during isoflurane anaesthesia. The times to recovery of the TOF ratio to 0.7 were 66 (13.4) min and 52 (16.3) min and the 25-75% recovery indices 14 (5.3) min and 10 (3.2) min, respectively, in the desflurane and isoflurane groups. There were no differences in the estimated potency or onset of action of rocuronium during desflurane and isoflurane anaesthesia. However, duration of action tended to be longer curing desflurane anaesthesia although only the differences in times to TOF ratio of 0.7 and the recovery indices were close to being significantly different (P = 0.0503 and 0.0560).      

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.     

The time-course of action and recovery of rocuronium 0.3 mg x kg(-1) in infants and children during halothane anaesthesia measured with acceleromyography

This study compares the time-course of action of neuromuscular paralysis after 0.3 mg x kg(-1) of rocuronium during nitrous oxide-halothane anaesthesia in children of three different age groups. With appropriate approval and informed consent from the parents, 51 children, ASA I-II, scheduled for elective surgery requiring muscle relaxation, were studied. The children were assigned to three groups according to age: group 1, 0-6 months; group 2, 6-24 months; and group 3, > 24 months of age. Induction of anaesthesia and tracheal intubation were performed under halothane anaesthesia. Acceleromyography of the thumb was recorded after supramaximal transcutaneous ulnar nerve stimulation using train-of-four (TOF) stimulation. Rocuronium 0.3 mg x kg(-1) was given as a rapid i.v. bolus prior to surgical incision. The onset time (time to max effect) and the maximal depth of the block, the time to recovery of the first twitch (T1) to 25% and 75% of its baseline, the recovery index (RI), and the time to recovery of the TOF ratio to 70% after the end of injection of rocuronium were all measured. The mean (SD) age of the children in groups 1, 2, and 3 was 3.1 (1.6), 12.6 (3.7), and 63 (46) months, respectively. The onset time of rocuronium was 47 (12), 83 (42) and 94 (12) s, respectively, in groups 1, 2, and 3 (P<0.05 group 1 vs. 2 and 3). One hundred percent block was achieved in 18/19 patients in group 1, 12/14 in group 2 and 6/18 in group 3. The times to 25% and 75% recovery of T1 and the time for recovery of the TOF ratio to 70% were all significantly longer in groups 1 and 2 compared to group 3. Group 1 and 2 showed no significant differences in recovery times. The RI was significantly prolonged in group 1 versus 3. The authors conclude that rocuronium 0.3 mg x kg(-1) during halothane anaesthesia causes more neuromuscular depression and has a longer duration of action in infants than in children older than 2 years.     

Neuromuscular blocking effects of rocuronium during desflurane, isoflurane, and sevoflurane anaesthesia

Purpose

To determine the magnitude of the potentiation of rocuronium by desflurane, isoflurane and sevoflurane 1.5 MAC anaesthesia.

Methods

In a prospective, randomised, study in 80 patients, the cumulative dose-effect curves for rocuronium were determined during anaesthesia with desflurane, sevoflurane and isoflurane (with N₂O 70%, 15 min steady state) or total intravenous anaesthesia (TIVA) using propofol/fentanyl. Neuromuscular block was assessed by acceleromyography (TOF-Guard®) after train-of-four (TOF) stimulation of the ulnar nerve (2Hz every 12sec, 200 μsec duration), Rocuronium was administered in increments of 100 μg·kg^?1 until first twitch (T₁) depression > 95%.

Results

Rocuronium led to more pronounced T₁ depression with desflurane or sevoflurane anaesthesia than with TIVA. The ED₅₀ and ED₉₅ were lower during desflurane (95 ± 25 and 190 ± 80 μg·kg^?1) and sevoflurane (120 ±30 and 210 ± 40 μg·kg^?1) than with TIVA (150 ± 40 and 310 ± 90 μg·kg^?1) (P < .01), while the difference was not significant for isoflurane (130 ± 40 and 250 ± 90 μg·kg^?1). Following equi-effective dosing (T₁ > 95%) the duration to 25% T₁ recovery, recovery index (25/75), and TOF_0.70 was: 13.2 ± 1.8, 12.7 ± 3.4, and 26.9 ± 5.7 min during anaesthesia with desflurane; 15.5 ± 5.0, 11.4 ± 3.8, and 31.0 ± 6.0 min with sevoflurane; 13.9 ± 4.7, 10.7 ± 3.3, and 26.3 ± 8.9 min with isoflurane; and 13.9 ± 3.9, 11.3 ± 5.7, and 27.5 ± 8,2 min with TIVA anaesthesia (P: NS).

Conclusion

Interaction of rocuronium and volatile anaesthetics resulted in augmentation of the intensity of neuromuscular block but did not result in significant effects on duration of or recovery from the block.     

ONSET AND RECOVERY OF ROCURONIUM (ORG 9426) AND VECURONIUM UNDER ENFLURANE ANAESTHESIA

We have studied the onset, duration of action and recovery indexof twice the ED₉₀ of rocuronium (Org 9426) (0.6 mg kg^–1)and of vecuronium (0.08 mg kg^–1) in patients during enf/uraneanaesthesia. Rocuronium had a significantly shorter mean onsettime of 1.8 (SD 0.4) min, compared with vecuronium 3.4 (0.8)min. Clinical duration (time for the first twitch in the train-of-fourto recover to 25% of control) was similar for both drugs (29(10) min vs 31 (12) min). Spontaneous recovery times (TOF ratio70%) did not differ significantly between rocuronium (47 (10)min) and vecuronium (44 (11) min). (Br. J. Anaesth. 1992;69:511–512)     

Neuromuscular recovery following rocuronium bromide single dose in infants

BACKGROUND: Rocuronium bromide, a steroid nondepolarizing muscle relaxant, has a rapid onset and an intermediate duration of action in infants, children and adults. However, clinical evidence shows a longer duration of recovery in small infants. The aim of this study was to investigate the influence of age on rocuronium recovery during the first year of life. METHODS: ASA I-II infants, scheduled for elective surgery under general anaesthesia and intubation were included after ethics committee approval and parents' written consent. According to age the patients were randomly allocated to receive either 0.45 mg.kg(-1) or 0.6 mg.kg(-1) rocuronium bromide in three age-groups: (A) 0-1 month, (B) 2-4 months and (C) 5-12 months. After induction with thiopentone (5-7 mg.kg(-1)), anesthesia was maintained with isoflurane without opioids. Prior to surgery, caudal block with bupivacaine (0.125%) 1.0 ml.kg(-1) and paracetamol 25 mg.kg(-1) rectally were given for analgesia. Efficacy variables were intubation conditions 60 s after administration of muscle relaxant (T(0)) and recovery of neuromuscular blockade measured as T(1) at 10, 25, 50 and 75 % of baseline, train-of-four (TOF) of 0.7 and Recovery Index (RI). Data were characterized by summary statistics and analysis of variance. RESULTS: A total of 61 infants with a median age range of 67 (2-364) days were included. Intubation conditions were excellent or good in all dose and age groups. T(0) in group A was reached in a range of 15-30 s, in others up to 60 s. T(1) recovery (T75) after 0.45 mg.kg(-1) was 56.4 +/- 16 (A), 62.7 +/- 32 (B) and 45.8 +/- 18 (C) min. Recovery times for of 0.6 mg.kg(-1) were 100.8 +/- 35 (A), 70.6 +/- 19 (B) and 63.4 +/- 21 (C) min, respectively. The TOF ratio (0.7) was 62.3 +/- 18 (A), 64.1 +/- 27 (B) and 43.7 +/- 12 (C) min using 0.45 mg.kg(-1) compared with 94.8 +/- 31 (A), 63.8 +/- 14 (B) and 67.5 +/- 18 (C) min with 0.6 mg.kg(-1). The differences of T75 and TOF 0.7 in A and C were significant (P 相似文献   

Nondepolarizing neuromuscular blocking drugs and train-of-four fade

The aim of this study was to examine differences in prejunctional effects of different relaxants by measuring the train-offour (TOF) fade during the onset and recovery of neuromuscular block. The relaxants studied were atracurium (225 μg · kg^?1), mivacurium (65 μg · kg^?1) rocuronium (300 μg · kg^?1)) and vecuronium (40 μg · kg^?1)). The TOF ratios were measured at approximate heights of T₁) (first response in the TOF) of 90, 75, 50, and 25%. The TOF fade (as shown by lower TOF ratios) increased with a decrease in the T₁) during onset of neuromuscular block. Although there was a slightly greater fade with atracurium and rocuronium during the onset of block, the differences among the relaxants were insignificant. It is concluded that the relative prejunctional effects of these relaxants are similar.     

Ketamine, but not priming, improves intubating conditions during a propofol–rocuronium induction

Purpose

Both ketamine and priming may shorten the onset time of rocuronium. This study investigates the effects of ketamine and priming as components of a propofol induction on intubating conditions and onset of neuromuscular block.

Methods

This prospective randomized double-blind study was performed in 120 American Society of Anesthesiologists (ASA) I–II patients who were assigned to one of four groups of 30 patients each: control, priming, ketamine, and ketamine-priming. Ketamine 0.5 mg ? kg^?1 or saline was given before priming and induction. Rocuronium 0.06 mg ? kg^?1 or saline was injected 2 min before propofol 2.5 mg ? kg^?1. This was followed by rocuronium 0.6 mg ? kg^?1 or by rocuronium 0.54 mg ? kg^?1 if priming was given. Intubation was performed one minute later. Intubating conditions were graded as excellent, good, or poor. Heart rate, noninvasive blood pressure, and train-of-four (TOF) response were monitored.

Results

Intubating conditions were graded excellent in 20% of the control group, 30% of the priming group, 47% of the ketamine group, and 57% of the ketamine-priming group. Analysis using forward stepwise regression indicated that ketamine improved intubating conditions (P = 0.001) but priming did not (P = 0.35). Time to reach a TOF count of zero was shortened by ketamine (P = 0.001) but not by priming (P = 0.94): 216 ± 20 s in the control group, 212 ± 27 s in the priming group, 162 ± 18 s in the ketamine group, and 168 ± 22 s in the ketamine-priming group.

Conclusion

A low-dose ketamine used with a propofol–rocuronium induction improved intubating conditions and shortened onset time. Priming did not influence intubating conditions or onset time.     

Early and late reversal of rocuronium and vecuronium with neostigmine in adults and children.

We investigated the influence of the timing of neostigmine administration on recovery from rocuronium or vecuronium neuromuscular blockade. Eighty adults and 80 children were randomized to receive 0.45 mg/kg rocuronium or 0.075 mg/kg vecuronium during propofol/fentanyl/N2O anesthesia. Neuromuscular blockade was monitored by train-of-four (TOF) stimulation and adductor pollicis electromyography. Further randomization was made to control (no neostigmine) or reversal with 0.07 mg/kg neostigmine/0.01 mg/kg glycopyrrolate given 5 min after relaxant, or first twitch (T1) recovery of 1%, 10%, or 25%. Another eight adults and eight children received 1.5 mg/kg succinylcholine. At each age, spontaneous recovery of T1 and TOF was similar after rocuronium and vecuronium administration but was more rapid in children (P < 0.05). Spontaneous recovery to TOF0.7 after rocuronium and vecuronium administration in adults was 45.7 +/- 11.5 min and 52.5 +/- 15.6 min; in children, it was 28.8 +/- 7.8 min and 34.6 +/- 9.0 min. Neostigmine accelerated recovery in all reversal groups (P < 0.05) by approximately 40%, but the times from relaxant administration to TOF0.7 were similar and independent of the timing of neostigmine administration. Recovery to T1 90% after succinylcholine was similar in adults (9.4 +/- 5.0 min) and children (8.4 +/- 1.1 min) and was shorter than recovery to TOF0.7 in any reversal group after rocuronium or vecuronium administration. Recovery from rocuronium and vecuronium blockade after neostigmine administration was more rapid in children than in adults. Return of neuromuscular function after reversal was not influenced by the timing of neostigmine administration. These results suggest that reversal of intense rocuronium or vecuronium neuromuscular blockade need not be delayed until return of appreciable neuromuscular function has been demonstrated. Implications: These results suggest that reversal of intense rocuronium or vecuronium neuromuscular blockade need not be delayed until return of appreciable neuromuscular function has been demonstrated. Although spontaneous and neostigmine-assisted recovery is more rapid in children than in adults, in neither is return of function as rapid as after succinylcholine administration.     

Effects of age on neuromuscular blockade by vecuronium as measured by accelography under sevoflurane anesthesia

We evaluated possible differential effects of age on a single bolus intravenous injection of vecuronium using accelography under sevoflurane anesthesia. Thirty anesthetized patients were divided into three groups of 10 patients as follows: group 1=age 1–5 years; group 2=age 20–40 years, and group 3=age >70 years. Vecuronium 0.1 mg·kg⁻¹ was given to facilitate tracheal intubation. Onset time, i.e., the time from the start of injection of the first dose of vecuronium to development of maximal twitch depression in group 1 was significantly shorter than those in groups 2 and 3 (103.5±30.4s, 166.5±32.7s, and 202.5±56.7s; mean±SD;P<0.01). Clinical duration, i.e., the time from completion of maximal block to 25% recovery of train-of-four (TOF) ratio in group 1 was significantly shorter than that in group 3 (43.6±12.0 min and 67.3±15.6 min;P<0.01). The reversal time from 25% to 75% of the TOF ratio after the administration of neostigmine in group 1 was not significantly different from those in groups 2 and 3 (172.5±73.9s, 219.0±59.7s, and 222.0±155.7s). The authors conclude that the time to maximal twitch depression after the administration of vecuronium is significantly shorter in children than that in adults, and that the fastest recovery from vecuronium is also observed in children.     

Neuromuscular effects of rocuronium in patients receiving beta- adrenoreceptor blocking, calcium entry blocking and anticonvulsant drugs

We have studied the onset and duration of action of rocuronium 0.6 mg kg-1 in patients receiving therapy for more than 1 month with beta- receptor blocking drugs (n = 16), calcium entry blocking drugs (n = 17) or anticonvulsant drugs (n = 14) and compared these data with those from a control group (n = 27). Anaesthesia comprised fentanyl, propofol infusion and nitrous oxide in oxygen. Neuromuscular block was monitored by measuring the force of contraction of the adductor pollicis muscle in response to train-of-four (TOF) stimulation. There were no significant differences in onset times between the four groups (mean 62- 76 s). Mean times to 25% recovery of T1 (first response in the TOF) and of the TOF ratio of 0.7 were 38 (SD 15) and 58 (22) min, 36 (8) and 61 (19) min, 40 (11) and 68 (22) min, and 25 (6) and 35 (9) min in the control, beta-blocker, calcium entry blocker and anticonvulsant groups, respectively (P < 0.01 between the anticonvulsant and other groups). We conclude that chronic therapy with anticonvulsant drugs reduces the duration of action of rocuronium.      

Neostigmine injected 5 minutes after low-dose rocuronium accelerates the recovery of neuromuscular function

Study ObjectiveTo determine whether neostigmine 5 minutes after 0.4 mg/kg rocuronium accelerates reversal.DesignProspective, randomized, comparative open-label study.SettingOperating room.Patients60 ASA physical status I and II patients, aged 18 to 65 years.InterventionsPatients received 0.4 mg/kg rocuronium during nitrous oxide (N₂O)-propofol-opioid anesthesia. Reversal of neuromuscular blockade was achieved with neostigmine, either at 0.03 mg/kg or 0.05 mg/kg intravenously (IV), together with glycopyrrolate administered 5 minutes after relaxant and compared with spontaneous recovery. Onset, depth, and duration of neuromuscular block, as well as recovery of train-of-four (TOF) to 0.8 and 0.9 were evaluated.Main ResultsTimes to achieve TOF ratios of 0.8 and 0.9 were significantly shorter when 0.03 mg/kg or 0.05 mg/kg neostigmine was administered 5 minutes after administration of rocuronium (20.2 ± 5 min and 22.6 ± 5.9 min or 17.8 ± 4.8 min and 19.4 ± 5.1 min, respectively) compared with controls (36.2 ± 8.5 min and 39.0 ± 8.7 min; P < 0.01). Duration to spontaneous T1 25% recovery after rocuronium was 15.5 ± 6.5 min versus 9.3 ± 2.3 min and 7.7 ± 1.6 min in the treatment groups (P < 0.01). Recovery index (T1 from 25% to 75%) was significantly shorter after neostigmine (7.1 ± 2.4 min and 5.7 ± 4.0 min) versus controls (13.3 ± 8.3 min; P < 0.01). Speed of reversal did not differ significantly between IV neostigmine doses of 0.03 mg/kg or 0.05 mg/kg.ConclusionNeostigmine accelerates recovery when administered 5 minutes after injection of IV rocuronium 0.4 mg/kg.