Comparison of recovery times from deep neuromuscular blockade between single bolus and continuous infusion of rocuronium

BACKGROUND: To prevent sudden unexpected movement of patients during surgery, muscle relaxants are used to maintain intense neuromuscular blockade.They are administered by intermittent bolus or continuous infusion.Rocuronium is often used for continuous infusion because it is known to lack cumulative effects. The purpose of this study was to compare recovery times from intense neuromuscular block to reappearance of muscle twitches after 0.1 Hz single twitch stimulation. MATERIALS AND METHODS: Seventy five patients were randomized to one of 3 groups.Patients in group 1 were administered a single bolus of rocuronium; groups 2 and 3 were given continuous infusion of rocuronium for 1 and 2 h, respectively.During anesthesia, neuromuscular blockade was monitored by TOF-watch(R) and regulated so as not to exceed more than 5 (PTC) during the infusion. After infusion, PTC was counted every 5 min until single twitch heights had reappeared and the time till the twitch reappeared was calculated. RESULTS: There was a good correlation between the time it took to observe a PTC and the first response of TOF time in each group.In a parallelism test, there were no significant differences. There were also no significant differences in recovery times from PTC to the reappearance of a single twitch between groups. CONCLUSIONS: There are no significant differences in recovery times-from deep neuromuscular blockade to reappearance of single twitch-regardless of the infusion time.When a PTC occurs during deep neuromuscular blockade, it may predict the remaining time of reappearance of a single twitch response.

Assessment of the Optimal Interval of Tetanic Stimulation for Post-Tetanic Count / 대한마취과학회지

Post-tetanic count(PTC) was a known monitoring method to evaluate intense neuromuscular blockade of peripheral muscles. It has been reported that intermittent tetanic stimulation(50 Hz for 5 sec.) every 6 to 10 min. during intense nondepolarizing neuromuscular blockade did not influence the recovery of neuromuscular transmission. However, the relatively frequent use of tetanic stimulation might be possible to influence the recovery of neuromuscular blockade and the repeated stimuli might result in a false recovery state. The purpose of this study was to determine the best interval time of tetanic stimulation for evaluation of the correct PTC. Sixty adult patients undergoing stomach operations were randomly allocated to three groups according to the interval of tetanic stimulation ; group 1 (6 min. n=20), group 2 (8 min. n=20) and group 3 (10 min. n=20). In all cases, Anesthesia was maintained with 50% nitrous oxide, 50% oxygen and 1-2% enflurane following induction of anesthesia with thiopental sodium 3-5 mg/kg. Neuromuscular block was achieved by intravenous pancuronium bromide 0.13 mg/kg before application of ulnar nerve stimuli using Myotest MKII. The adduction force of the resultant thumb twitch was measured by the acceleration of a small piezo-electric ceramic wafer with electrodes of Mini-accelograph and recorded by Datascope 2200 I After 1 Hz single twitch stimulation, a tetanic stimulus(50 Hz) was applied for 5 sec. Three seconds later, the single twitch stimulation was again applied for 1 min. followed by 1 min. of TOF stimulation. This pattem of tetanic stimulation was continued by the interval of 6, 8 and 10 min. The results were as follows: 1. The continuance (which was the percentage when PTC was continuously increased, not intermittently reduced) was 73.7% in group 1 and 2, but 100% in group 3 and there were statistically significance. 2. In the regression analysis between FI'C and time from PTC1, we yielded the following equations ; Y=10+3.5X (r(2)=0.71) for group 1, Y=8.6+4.1X (r(2)=0.78) for group 2 and Y=9.8+5.7X (r(2)=0.69) for group 3. The slope and intercept of the line of group 3 showed significantly different to that of group 1 and 2 (p<0.001). The more frequent tetanic stimulation reduced the time to arrive the same PTC. 3. The time from PTCl to TOFl was 51.6+/-3.9 min. in group 1, 65+/-5 min. in group 2 and 69+/-4.3 min. in group 3. There were no statistically significance, but they had trend to reduce by more frequent tetanic stimulation. 4. PTC was 12.9+/-0.9 in group 1, 14.9+/-1.5 in group 2 and 13.2+/-0.8 in group 3 when TOF1 was appeared, and 38.3+/-2.3 in group 1, 33.3+/-2.3 in group 2 and 32.4+/-2.6 in group 3 when the second response to TOF stimulation(TOF2) was recorded(meanSEM). There were no statistically significance. With the above results the authors concluded that 10 min. will be the optimal interval of the tetanic stimulation for the correct PTC, and recognized that the interval of tetanic stimulation was not related to the time from PTC1 or PTC at TOF twitches.

Relationship between the Change of PTC and the Response of Endotracheal Intubation after Vecuronium Induction / 대한마취과학회지

The relationship between the post-tetanic count(PTC) and the response of tracheal intubation after vecuronium-induced neuromuscular blockade was studied in 99 cases who were ASA 1 or 2 adult patients. All patients were premedicated with glycopyrrolate 0.2mg and hydroxizine 1 mg/kg IM 1 hour before induetion, and were inducted with pentothal sodium Smg/kg and O2- N2O(50%) enflurane(2%). The patients were randomly divided to two groups according to dose of vecuronium applied after inducion ; 0.08 mg/kg(n=54) group and 0.12 mg/kg(n=45) group. Neuromuscular blockade was monitored by stimulation of the ulnar nerve at the wrist with single twitch using INNERVATOR(Fisher and Paykel Co.). Post tetanic count(PTC) was counted at different times, i.e., 0, 10, 20, 25, 30 and 35 seconds, 9 persons respectively at each time, after disappearance of single twitch. Tracheal intubation was performed immediately after counting of PTC. The response of tracheal intubation was appreciated based on vocal cord reflex, coughing or barking and patient movement. The time from administration of vecuronium to disappearance of single twitch was 167.8+/-23.4 seconds in 0.08mg/kg group and 163.7+/-51.1 seconds in 0.12mg/kg group and there was no statistical difference. After complete disappearance of single twitch, the PTC was zero at 35 seconds in 0.08 mg/kg group and at 25 seconds in 0. 12 mg/kg group. While the PTC was lowering, the lower intubation condition score should be expected, but the 0 of PTC did not coin-cided with the 0 of intubation condition score. However, the 0 of PTC did not always indicated that response to tracheal intubation could be disappear completely. Profound neuromuscular blockade did not reduce the hemodynamic responses to tracheal intubation.

Clinical Study of Post - tetanic Count ( PTC ) during Vecuronium - induced Intense Neuromuscular Blockade / 대한마취과학회지

Vecuronium induced intense neuromuscular blockade was evaluated in 40 USA class l, ll adult patients using the post tetanic count (PTC) and train-of-four(TOF) methods. All patients were anesthetized with thiopental sodium, nitrous oxide(50%), and enflurane(1~2%). Neuromuscular monitoring commended immediately after administration of thiopental sodium. The ulnar nerve was stimulated using surface electrodes and the mechanical response of the adductor policis muscle recorded using the Acclograph, neuromuscular transmission monitor. TOF nerve stimulation was used every 15s. After supramaximal stimulation was achieved a bolus of vecuronium 0.1mg/kg was injected intravenously. The traches was intubated when TOF response was depressed to 95% or above to control twitch height and the lungs ventilated with a tidal volume of 10ml/kg and a rate of 14 b.p.m. The patients were allocated randomly to two groups of 20 patients each. Patients in control group were allowed to recover TOF response spontaneously, and in PTC group were applied tetanic stimulation(50Hz for 5s) at 7 minutes intervals during no TOF response. In PTC group, the tetanic stimulation was preceded by a 30s period of 1Hz stimulation on each occasion, which was continued after the 3s pause. Duration of no TOF response in each group, and relationship between first post tetanic twitch height of PTC and time to first reaction to TOF nerve stimulation in PTC group were measured. In the results, duration of no TOF response was shortened by tetanic stimulation(p<0.01). There was a close inverse correlation between first post tetanic twitch height or PTC and time to first reaction to TOF nerve stimulation (p<0.01). It was concluded that PTC method appeared to be a valuable supplement to TOF nerve stimulation in assessment and trend for vecuronium induced intense neuromusclular blockade.