四个成串刺激和双短强直刺激用于评价神经肌肉传导阻滞的比较

采用单盲法对１０例患者比较目测或触感四个成串刺激（ＴＯＦ）和双短强直刺激（ＤＢＳ）肌收缩效应衰减，用于评价神经肌肉传导阻滞的相关性及可靠程度。结果发现，ＤＢＳ比值（ＤＢＳＲ）印ＴＯＦ比值（Ｔ４／Ｔ１）之间具有良好的相关性（ｒ＝０．９７，Ｐ＜０．００１）。在 Ｔ４／Ｔ１；低于 ０．７时、ＴＯＦ和ＤＢＳ的衰减检出率分别为 ３５％和 ６５％（Ｐ＜０．０１）；当 Ｔ４／Ｔ１为 ０． ４～０． ５时，ＴＯＦ和 ＤＢＳ的衰减检出率分别为 ３５／和８０％；当Ｔ４／Ｔ１为０．５～０．６时，ＴＯＦ的衰减检出率为７％，而ＤＢＳ的衰减检出率为６７％；当Ｔ４／Ｔ１为０．６～０．７时，ＴＯＦ已不能检测到衰减。但ＤＢＳ的衰减检出率仍有：３６％．但当Ｔ４／Ｔ１恢复到０．７以上时，ＤＢＳ的分辨率仅为２％．由此可见，如果仅凭目测或触感评价术后肌张力的恢复情况，则ＴＯＰ未检测到衰减并不能排除严重的肌张力恢复不全，而ＤＢＳ未检测到衰减时，肌张力已较好恢复。     

Is the diagnosis of significant residual neuromuscular blockade improved by using double-burst nerve stimulation?

This study evaluated the use of double-burst stimulation (DBS) in the diagnosis of significant post-operative residual neuromuscular blockade. Ninety patients were allocated to three equal groups. In Group A the degree of residual neuromuscular blockade was assessed by clinical criteria (CC) only; in Group B by CC and manual evaluation of the response to train-of-four (TOF) nerve stimulation; and in Group C by CC, manual evaluation of the response to TOF, and DBS stimulation. Immediately after arrival in the recovery room mechanical twitch was recorded using TOF stimulation. The mean (+/- SD) TOF ratios were 0.53 +/- 0.19 in Group A, 0.67 +/- 0.11 in Group B and 0.81 +/- 0.08 in Group C. The incidence of a TOF ratio of less than 0.7 was 83.3% in Group A, 56.7% in Group B and 6.7% in Group C. It is concluded that the use of DBS enabled the anaesthetist to recognize significant residual block and thus reduced the incidence of post-operative residual neuromuscular blockade.     

Tactile fade detection with hand or wrist stimulation using train-of-four, double-burst stimulation, 50-hertz tetanus, 100-hertz tetanus, and acceleromyography

Residual neuromuscular blockade can be evaluated using acceleromyography, tactile assessment of train-of-four (TOF), double-burst stimulation (DBS), 50-Hz tetanus, or 100-Hz tetanus. Nerve stimulation can be at the hand or the wrist. We compared all these tests at both sites of stimulation. Rocuronium was given to 32 patients under sevoflurane anesthesia. The mechanomyographic adductor pollicis TOF ratio was measured at one extremity. In the other, stimulation was at the hand or the wrist, by random allocation, and the acceleromyographic TOF ratio was measured. During recovery, a blinded observer estimated tactile fade. The TOF fade became undetectable when mechanomyographic TOF ratio was (mean +/- sd) 0.31 +/- 0.15. For DBS, this threshold was 0.76 +/- 0.11. For 50-Hz tetanus, it was 0.31 +/- 0.15. For 100-Hz tetanus, it was 0.88 +/- 0.18, with a range of 0.14-1.00. These tactile responses were the same for hand and wrist stimulation. When acceleromyographic TOF ratio reached 1.0, the mechanomyographic TOF ratio was 0.89 +/- 0.06. With stimulation in the hand, acceleromyographic TOF ratio >1.0 was less frequent than at the wrist. To exclude residual paralysis, TOF, DBS, and 50-Hz tetanus are inadequate, 100-Hz tetanus is unreliable, and acceleromyography performs best.     

Manual evaluation of residual curarization using double burst stimulation: a comparison with train-of-four

Double burst stimulation (DBS) is a new mode of stimulation developed to reveal residual neuromuscular blockade under clinical conditions. The stimulus consists of two short bursts of 50 Hz tetanic stimulation, separated by 750 ms, and the response to the stimulation is two short muscle contractions. Fade in the response results from neuromuscular blockade as with train-of-four stimulation (TOF). The authors compared the sensitivity of DBS and TOF in the detection of residual neuromuscular blockade during clinical anaesthesia. Fifty-two healthy patients undergoing surgery were studied. For both stimulation patterns the frequencies of manually detectable fade in the response to stimulation were determined and compared at various electromechanically measured TOF ratios. A total of 369 fade evaluations for DBS and TOF were performed. Fade frequencies were statistically significantly higher with DBS than with TOF, regardless of the TOF ratio level. Absence of fade with TOF implied a 48% chance of considerable residual relaxation as compared with 9% when fade was absent with DBS. The results demonstrate that DBS is more sensitive than TOF in the manual detection of residual neuromuscular blockade.     

Tactile evaluation of fade of the train-of-four and double-burst stimulation using the anaesthetist's non-dominant hand

We have studied detection of fade in response to train-of-four (TOF), double-burst stimulation3,3 (DBS3,3) or DBS3,2, assessed tactilely by the anaesthetist using the index finger of the non-dominant hand and the thumb of the patient, compared with that assessed when the index finger of the dominant hand was used. The probability of detection of any fade in response to TOF or DBS3,3 using the non-dominant hand was significantly less than when the dominant hand was used (P < 0.05). The probability of identification of fade in response to DBS3,2 assessed using the non-dominant hand was comparable with that evaluated using the dominant hand when TOF ratios were 0-0.9, but when TOF ratios reached 0.91-1.00, detection using the non-dominant hand was significantly less common than with the dominant hand (12% vs 33%; P < 0.05). Using the non-dominant hand, the probability of detection of fade in response to ulnar nerve stimulation was less than that with the dominant hand and only the absence of DBS3,2 fade ensured sufficient recovery of neuromuscular block.      

Double burst stimulation for monitoring profound neuromuscular blockade: a comparison with posttetanic count and train of four.

Double burst stimulation (DBS) is a new nerve stimulation pattern introduced to facilitate tactile evaluation of recovery from neuromuscular blockade. DBS consists of two bursts of high frequency stimulations separated by a short time interval. The relationships between DBS, post-tetanic count (PTC) and train-of-four (TOF) on the evoked twitch response was investigated in 16 surgical patients and 7 intensive care patients given atracurium for muscle relaxation. A significant correlation between the twitch height of the first response to DBS and the number of post-tetanic responses was demonstrated when PTC was more than five (r = 0.47, p < 0.0003). When the first twitch of TOF was still not measurable, the first twitch of DBS ranged from 0 to 20% of the TOF-control twitch height. Furthermore the DBS ratio was significantly correlated to the TOF ratio (r = 0.92-0.96, p < 0.0002). It is concluded that DBS not only can be used for monitoring of recovery from neuromuscular blockade, but also for monitoring of intense degrees of neuromuscular blockade.     

Impaired neuromuscular transmission after recovery of the train-of-four ratio

BACKGROUND: Residual neuromuscular blockade may increase the risk of development of post-operative pulmonary complications, but is difficult to detect clinically. It was speculated that patients may have impaired neuromuscular transmission after surgery of long duration, despite the recovery of the train-of-four (TOF) ratio. METHODS: The muscle force (mechanomyography), motor compound muscle action potential amplitude and fatigue of the adductor pollicis (AP) muscle were assessed after recovery of the TOF ratio to 0.9. Thirteen patients receiving repetitive administration of neuromuscular blocking agents (NMBAs) during surgery (median, 5.3 h; interquartile range, 3.4-6 h) were studied post-operatively in the intensive care unit. At the time of the measurements, patients were scheduled for extubation and the AP TOF ratio amounted to a mean (standard deviation, SD) of 0.94 (0.05). Six healthy volunteers of similar age, weight and gender were studied for comparison. Force-frequency curves were generated by stimulation (10-80 Hz) of the ulnar nerve, and the AP electromyogram (EMG) amplitude was measured, in parallel, before and after evoked muscle fatigue. RESULTS: The maximum AP force at a stimulation frequency of 20-80 Hz was significantly lower in patients than in controls [40 N (16 N) vs. 65 N (18 N) at 80 Hz]. In patients, but not in controls, the EMG amplitude decreased with increasing nerve stimulation frequency, and a tetanic fade of both force and EMG, amounting to 0.41 (0.33) (EMG) and 0.61 (0.35) (mechanomyography) at 80 Hz, was observed. Force after fatiguing contractions did not differ between the groups. CONCLUSION: After repetitive administration of NMBAs during surgery, even with recovery of the TOF ratio to 0.9 or more, muscle weakness from impaired neuromuscular transmission can occur. The clinician should consider that post-operative recovery of the TOF ratio to 0.9 does not exclude an impairment of neuromuscular transmission.     

Residual paralysis at the time of tracheal extubation

Respiratory and pharyngeal muscle function are impaired during minimal neuromuscular blockade. Tracheal extubation in the presence of residual paresis may contribute to adverse respiratory events. In this investigation, we assessed the incidence and severity of residual neuromuscular block at the time of tracheal extubation. One-hundred-twenty patients presenting for gynecologic or general surgical procedures were enrolled. Neuromuscular blockade was maintained with rocuronium (visual train-of-four [TOF] count of 2) and all subjects were reversed with neostigmine at a TOF count of 2-4. TOF ratios were quantified using acceleromyography immediately before tracheal extubation, after clinicians had determined that complete neuromuscular recovery had occurred using standard clinical criteria (5-s head lift or hand grip, eye opening on command, acceptable negative inspiratory force or vital capacity breath values) and peripheral nerve stimulation (no evidence of fade with TOF or tetanic stimulation). TOF ratios were measured again on arrival to the postanesthesia care unit. Immediately before tracheal extubation, the mean TOF ratio was 0.67 +/- 0.2; among the 120 patients, 70 (58%) had a TOF ratio <0.7 and 105 (88%) had a TOF ratio <0.9. Significantly fewer patients had TOF ratios <0.7 (9 subjects, 8%) and <0.9 (38 subjects, 32%) in the postanesthesia care unit compared with the operating room (P < 0.001). Our results suggest that complete recovery from neuromuscular blockade is rarely present at the time of tracheal extubation.     

Evaluation of residual neuromuscular blockade using modified double burst stimulation

Background: To assess the degree of residual neuromuscular blockade, double burst stimulation (DBS) is commonly applied in the clinical setting. However, fades in response to DBS_3,3 can rarely be identified manually when train-of-four (TOF) ratios are ≧0.70, and, in contrast, fades in response to DBS_3,2 are felt manually in an undesirably high proportion of cases, even at TOF ratios greater than 0.7. We investigated whether a new monitoring method, modified DBS, would be useful to determine an adequate degree of recovery from neuromuscular blockade. For modified DBS, two burst stimuli were applied at an interval of 750 ms. The first stimulation in the modified DBS consisted of two stimuli of 0.3 ms duration at 50 Hz and the second of two stimuli of 0.2 ms duration at 50 Hz. Methods: Forty-five adult patients undergoing elective nitrous oxide-oxygen-isoflurane anesthesia were randomly divided into one of three groups: DBS_3,3 group (n=15), DBS_3,2 group (n=15), or modified DBS group (n=15). During recovery from vecuroni-um-induced neuromuscular blockade, on both forearms, DBS_{3, 3}, DBS_{3, 2}, and modified DBS were delivered in the DBS_{3, 3} group, DBS_{3, 2} group, and modified DBS group, respectively. One hand and forearm (fixed arm) were immobilized to quantify the degree of neuromuscular blockade mechanically, and the contralateral arm (free arm) was unrestrained. An observer deter-mined tactilely on the free arm the presence or absence of fade in response to the three DBS patterns. Results: Probabilities of detection of fade in response to the DBS_{3, 3} were 67% (TOF ratio of 0.51–0.60), 40% (0.61–0.70), 19% (0.71–4).80), 5% (0.81–0.90), and 0% (0.91–1.00). Those to the DBS₃, ₂ were 95% (0.51–0.60), 93% (0.61–0.70), 83% (0.71–0.80), 65% (0.81–0.90), and 38% (0.91–1.00). Those to modified DBS were 90% (0.51–0.60), 86% (0.61–0.70), 65% (0.71–0.80), 25% (0.81–0.90), and 3% (0.91–1.00). The modified DBS was more sensitive in diagnosing residual neuromuscular blockade than DBS_{3, 3} at the TOF ratio of 0.51–0.90, but was less sensitive than DBS_{3, 2} at the TOF ratio of 0.81–1.00 (P < 0.05). Conclusion: Our results indicate that the modified DBS may be a useful stimulation pattern to diagnose the adequacy of recovery from neuromuscular blockade.     

Acceleromyography in neonates and small infants: baseline calibration and recovery of the responses after neuromuscular blockade with rocuronium

BACKGROUND: We have evaluated the use of the TOF-Guard (TOF, train-of-four) acceleromyographic thumb responses to ulnar nerve stimulation in neonates and infants and the return of the responses after neuromuscular blockade. METHODS: Baseline acceleromyographic recording of thumb adduction to ulnar nerve stimulation during volatile anaesthesia was performed in 22 babies aged less than 30 weeks. At the start of stimulation the automatic set-up procedure of the TOF-Guard was used to see if a 100% control twitch height could be achieved. Irrespective of the ability to achieve a 100% control twitch height, TOF stimulation was used thereafter. When no automatic 100% control twitch could be reached, the transducer signal gain factor was set manually to obtain a 100% value. In 14 of the 22 children the recovery after neuromuscular blockade with rocuronium 0.3 mg kg(-1) was recorded. RESULTS: In nine of 22 patients a 100% baseline twitch height was obtained with the automatic set-up. In the other 13 babies the TOF-Guard display indicated that the transducer signal was too low. The mean time to recovery of control twitch to 75% of baseline after rocuronium 0.3 mg kg(-1) was 51 min (SD = 21) and the time to recovery of the TOF ratio to 70% was 49 min (SD = 19). The mean final twitch height and TOF after recovery from rocuronium blockade were 101% (SD = 15) and 92% (SD = 12), respectively. CONCLUSION: The recovery of the responses after neuromuscular blockade to near baseline values shows that acceleromyography can be used to measure neuromuscular block and recovery in neonates and infants.     

Recovery from vecuronium neuromuscular blockade following neostigmine administration in infants, children, and adults during halothane anesthesia

To determine whether neostigmine had different effects in pediatric patients during vecuronium neuromuscular blockade, the rate of recovery following neostigmine administration was compared in infants (n = 8), children (n = 10), and adults (n = 10) during nitrous oxide-halothane anesthesia. After induction of anesthesia, patients received 100 micrograms/kg of vecuronium. The EMG response of the adductor pollicis was monitored after train-of-four (TOF) stimulation of the ulnar nerve every 20 s. When the first twitch of TOF spontaneously recovered to 10% of control value, neostigmine was injected (40 micrograms/kg in adults, 30 micrograms/kg in infants and children). During the first few minutes following neostigmine administration, no differences were observed between the three groups. After the 8 min, recovery was more rapid in children than in infants and adults up to and including the 15th min. Ten minutes after neostigmine administration, the first twitch (mean +/- SD) reached 97 +/- 3%, 99 +/- 2%, and 97 +/- 5% of control value in infants, children, and adults, respectively; TOF ratio was greater in children (0.96 +/- 0.03) than in either adults (0.82 +/- 0.17) or in infants (0.83 +/- 0.14) (P less than 0.05). During the first minutes after neostigmine administration, the lack of difference in TOF recovery in the three groups suggests that neostigmine is the main factor of recovery. In contrast, the more complete recovery after the eighth minute in children could be due to the faster rate of spontaneous recovery from vecuronium induced neuromuscular blockade in children.     

Does repetition of post‐tetanic count every 3 min during profound relaxation affect accelerographic recovery of atracurium blockade?

BACKGROUND: Post-tetanic count is a valuable method to assess profound neuromuscular blockade. However, subsequent responses to repetitive stimulation might be altered due to post tetanic facilitation (PTF). To avoid PTF, it has been advocated to limit the interval of stimulation from 6 to 10 min. The impact of PTF on 90% recovery of the TOF ratio has not been evaluated. Therefore, we assessed the effect of repetitive PTC stimulation on atracurium blockade with the primary outcome being the time to reach 90% TOF recovery in comparison to classical TOF stimulation. METHODS: After informed consent 20 patients ASA I-II, scheduled for peripheral surgery under general anaesthesia and requiring tracheal intubation were enrolled into the study. Anaesthesia was induced with fentanyl, propofol, and atracurium, 0.5 mg kg(-1). Neuromuscular characteristics were assessed at the adductor pollicis by a TOF Watch((R)) accelerometer (Organon, Teknika, Holland) on each arm. After onset of maximum neuromuscular blockade, repetitive PTC every 3 min on one arm and repetitive TOF stimulation every 15 s on the opposite arm was performed. The following parameters were recorded: onset of maximum blockade, mean time of PTC stimulation, the maximum number of responses to PTC, time of the first and second TOF responses, and recovery profile until 90% TOF ratio. RESULTS: Time to reach 90% TOF recovery was similar on both arms (48 +/- 9 min), with a difference of 16 +/- 38 s between the arms (P = 0.64). The first and second responses of the TOF on the PTC-stimulated arm appeared at 29 +/- 8 min and 33 +/- 7 min, respectively. On the other arm the responses appeared at 30 +/- 8 min and 35 +/- 8 min, respectively (P < 0.05). CONCLUSION: Repetitive PTC stimulation every 3 min hastened the first and second responses of the TOF stimulation but we could not detect a significant difference in the 90% recovery of TOF ratio during atracurium blockade.     

Residual Block after Mivacurium with or without Edrophonium Reversal in Adults and Children

Background: The rapid recovery from mivacurium-induced neuromuscular block has encouraged omission of its reversal. The purpose of this study was to determine, in children and in adults, whether failure to reverse mivacurium neuromuscular block was associated with residual neuromuscular block on arrival in the postanesthesia care unit.

Methods: In 50 children, aged 2-12 yr, and 50 adults, aged 20-60 yr, anesthesia was induced and maintained with propofol and fentanyl, and neuromuscular block was achieved by an infusion of mivacurium, to maintain one or two visible responses to train-of-four (TOF) stimulation of the ulnar nerve. At the end of surgery, mivacurium infusion was stopped, and 10 min later, reversal was attempted with saline or 0.5 mg *symbol* kg sup -1 edrophonium by random allocation. On arrival in the postanesthesia care unit, a blinded observer assessed patients clinically and by stimulation of the ulnar nerve with a Datex electromyogram in the uncalibrated TOF mode.

Results: Children arrived in the postanesthesia care unit 8.2 +/-3.4 min after reversal of neuromuscular block and showed no sign of weakness, either clinically or by TOF stimulation. Although TOF ratio was greater in children who had received edrophonium (1.00 +/-0.05 vs. 0.93+/-0.01, P < 0.01), TOF was > 0.7 in all children. Adults arrived in the postanesthesia care unit 12.9+/- 5.3 min after reversal of neuromuscular block (P < 0.01 vs. children). Six in the saline group demonstrated weakness (two required immediate reversal of neuromuscular block, and TOF was < 0.7 in four others), compared with TOF < 0.7 in only one of the edrophonium group (P < 0.05).     

The Relationship between Acceleromyographic Train-of-four Fade and Single Twitch Depression

Background: During offset of nondepolarizing neuromuscular block, a train-of-four (TOF) fade ratio of 0.70 or greater is considered to reliably indicate the return of single twitch height (T1) to its control value. Studies using mechanomyography or electromyography confirm this observation. The authors' impressions when using the acceleromyograph as a neuromuscular monitor did not support these results. Therefore, the authors studied the relation between T1 and the TOF ratio (when measured by acceleromyography) during recovery from neuromuscular block.

Methods: Sixteen adult patients were studied. Anesthesia was induced with intravenous opioid plus 2.0-2.5 mg/kg propofol. Laryngeal mask placement or tracheal intubation was accomplished without the use of muscle relaxants. Anesthesia was maintained with nitrous oxide, desflurane (2.0-3.0%, end- tidal), and fentanyl. The response of the thumb to ulnar nerve stimulation was recorded with the TOF-Guard(R) acceleromyograph (Organon Teknika BV, Boxtel, The Netherlands). TOFs were administered every 15 s. After final calibration, 0.15 mg/kg mivacurium was administered. No further relaxants were administered. T1 and the TOF ratio were then recorded until the TOF ratio had returned to its initial value (+/- 5%).

Results: At a TOF ratio of 0.70 (during recovery of neuromuscular function), T1 averaged only 69 +/- 8% of control. At a TOF ratio of 0.90, T1 averaged 86 +/- 5% of control. To achieve 90% recovery of T1, a TOF ratio of 0.93 +/- 0.08 was required.     

A case report of monitoring neuromuscular blockade during anesthesia in a patient with facioscapulohumeral muscle dystrophy]

Facioscapulohumeral muscle dystrophy (FSHMD) is characterized by slowly progressive wasting of facial, pectoral and shoulder-girdle muscles that begins in adolescence. A 31 year-old man with FSHMD had dystrophic changes in the deltoid, anterior serratus and pectoralis major muscles but not in the distal muscle of his arms and legs. He underwent an operation for thoraco-scapula fixation under enflurane-nitrous oxide anesthesia with vecuronium 6 mg. At the end of the surgical procedure, the train-of-four (TOF) responses of a thumb and a toe, as measured by using an acceleration transducer, were recorded simultaneously. TOF stimulation in an arm demonstrated an apparent fade phenomenon (TOF; 0.54), while a TOF test in the leg showed complete recovery of the TOF ratio (TOF; 1.0). The patient revealed no clinical signs of residual neuromuscular blockade. It was clear that there was a difference in the degree of neuromuscular block between the arm and the leg in a FSHMD patient. Use of the peripheral nerve stimulator only in the arm may be an unreliable guide to assess neuromuscular block in FSHMD patients. Therefore, two sites should be chosen for monitoring neuromuscular blockade in a FSHMD patient.     

Twitch tension and train-of-four ratio during prolonged neuromuscular monitoring at different peripheral temperatures

In eight healthy patients, the influence of the train-of-four (TOF) response of prolonged neuromuscular monitoring and of different peripheral temperatures was studied during normal core temperature. Anaesthesia was induced and maintained with midazolam-fentanyl and a 70/30% mixture of nitrous oxide and oxygen. The mechanical TOF response of the adductor pollicis muscle (twitch tension and TOF ratio), was recorded simultaneously in both hands using supramaximal TOF stimulation of the ulnar nerve at the wrist. One arm was kept normothermic. The other arm was cooled using cold infusions and cold packings. Skin, muscle and core temperatures were continuously measured. In the normothermic arm (skin temperature greater than 32.0 degrees C), the twitch tension and TOF ratio were unchanged following 130-230 min of continuous nerve stimulation. In the hypothermic arm the twitch tension and TOF ratio showed only minor variations above a skin temperature of 32.0 degrees C (corresponding to a mean muscle temperature of 34.5 +/- 0.3 degrees C). Below a skin temperature of 32.0 degrees C a progressive decrease in TOF response was recorded. A linear relationship was found between skin temperature and TOF response as well as between muscle temperature and TOF response. At a skin temperature of 27.0 degrees C (corresponding to a mean muscle temperature of 30.8 +/- 0.4 degrees C), an approximate 20% reduction in twitch tension and a 10% decrease in TOF ratio were recorded with a considerable interindividual variation. We conclude that prolonged TOF nerve stimulation does not change the mechanical twitch response in patients with a normal central and peripheral temperature. A peripheral skin temperature below 32.0 degrees C with sustained and normal body temperature is, however, associated with changes in both twitch tension and TOF ratio that may be a source of error when evaluating neuromuscular function.     

经皮电刺激内关穴监测拇内收肌神经肌肉阻滞的准确性

目的 评价经皮电刺激内关穴监测拇内收肌神经肌肉阻滞的准确性.方法 择期全麻下拟行腹部手术患者35例,年龄40～60岁,ASAⅠ～Ⅲ级,体重指数≤35 kg/m2.麻醉诱导完毕后所有患者行气管插管后机械通气,记录神经肌肉阻滞监测仪经内关穴与经尺神经监测的刺激强度和传感器的增益值;术中单次静脉注射阿曲库铵0.5 mg/kg,采用神经肌肉阻滞监测仪经内关穴与经尺神经监测的阿曲库铵起效时间、TOF比值(T4/T1比值)恢复至25%、90%的时间.结果 经皮电刺激尺神经和内关穴所得的电流强度及传感器的增益值差异无统计学意义(P>0.05);经皮电刺激尺神经和内关穴监测的阿曲库铵起效时间、TOF比值恢复至25%、90%的时间差异无统计学意义(P>0.05).结论 肌松监测仪的电极置于内关穴部位可准确地监测神经肌肉阻滞程度.     

Utility of double burst stimulation in the detection of residual neuromuscular blockade

OBJECTIVE: To assess the usefulness of double burst stimulation (DBS) for detecting neuromuscular blockade caused by atracurium and vecuronium. PATIENTS AND METHODS: One hundred nineteen adult patients were randomly assigned to receive atracurium (n = 62) or vecuronium (n = 57), with electromyographic monitoring of the number of responses to train of four (TOF) stimuli, TOF-ratio (TR) and the amplitude of the first TOF response (T1) in the pollicis adductor and the response to neurostimulator DBS in the contralateral forearm. During recovery from neuromuscular blockade an independent anesthesiologist manually assessed two responses to DBS every minute as being clearly differentiated, doubtful or undifferentiated. The results were later compared to T1 and TR. RESULTS: Significant differences (p < 0.05) between groups were observed for TR in doubtful (0.27 +/- 0.18 and 0.34 +/- 0.17 for atracurium and vecuronium, respectively) and undifferentiated (0.34 +/- 0.22 and 0.43 +/- 0.18, respectively) responses to DBS, and for T1 with three TOF responses (26.0 +/- 13.6 and 33.1 +/- 14.2, respectively) or four responses (30.9 +/- 14.1 and 38.7 +/- 18.4, respectively). T1 values when TR was 0.75 (extubation criterion) were 68.1 +/- 23.8% and 60.5 +/- 17.4% for the atracurium and vecuronium groups, respectively (NS). CONCLUSIONS: Assuming that DBS reduces the risk of residual curarization and that a TOF-ratio greater than 0.75 indicates adequate recovery from neuromuscular blockade, manual assessment of DBS response as obtained in this study indicates curarization and equal responses do not guarantee its absence. The most reliable index of recovery from neuromuscular blockade is the TR obtained by electromyographic monitoring.     

The relationship between acceleromyographic train-of-four fade and single twitch depression

BACKGROUND: During offset of nondepolarizing neuromuscular block, a train-of-four (TOF) fade ratio of 0.70 or greater is considered to reliably indicate the return of single twitch height (T1) to its control value. Studies using mechanomyography or electromyography confirm this observation. The authors' impressions when using the acceleromyograph as a neuromuscular monitor did not support these results. Therefore, the authors studied the relation between T1 and the TOF ratio (when measured by acceleromyography) during recovery from neuromuscular block. METHODS: Sixteen adult patients were studied. Anesthesia was induced with intravenous opioid plus 2.0-2.5 mg/kg propofol. Laryngeal mask placement or tracheal intubation was accomplished without the use of muscle relaxants. Anesthesia was maintained with nitrous oxide, desflurane (2.0-3.0%, end-tidal), and fentanyl. The response of the thumb to ulnar nerve stimulation was recorded with the TOF-Guard acceleromyograph (Organon Teknika BV, Boxtel, The Netherlands). TOFs were administered every 15 s. After final calibration, 0.15 mg/kg mivacurium was administered. No further relaxants were administered. T1 and the TOF ratio were then recorded until the TOF ratio had returned to its initial value (+/- 5%). RESULTS: At a TOF ratio of 0.70 (during recovery of neuromuscular function), T1 averaged only 69 +/- 8% of control. At a TOF ratio of 0.90, T1 averaged 86 +/- 5% of control. To achieve 90% recovery of T1, a TOF ratio of 0.93 +/- 0.08 was required. CONCLUSION: Assumptions regarding the relation between T1 and the TOF ratio derived from studies using mechanomyography and electromyography do not necessarily apply to observations obtained using acceleromyography.     

Tactile evaluation of the response to double burst stimulation decreases, but does not eliminate, the problem of postoperative residual paralysis

Background: Routine perioperative monitoring with accelero-myography might prevent residual block, whereas routine tactile evaluation of the response to train-of-four (TOF) nerve stimulation does not. The purpose of this prospective, randomised and blinded study was to evaluate the effect of manual evaluation of the response to double burst stimulation (DBS_3.3) upon the incidence of residual block. Methods: Sixty adult patients scheduled for elective abdominal surgery were included in the study. Pancuronium 0.08 to 0.1 mg kg^?1 was given for relaxation and tracheal intubation. For maintenance of neuromuscular block, pancuronium 1–2 mg was administered. The patients were randomly allocated into two groups. In group DBS (double burst stimulation) the degree of block during anaesthesia was assessed by manual evaluation of the response to TOF nerve stimulation. During reversal, when no fade was detectable in the TOF response, the stimulation pattern was changed to DBS_3.3. The trachea was extubated when the anaesthetist judged the neuromuscular function to have recovered adequately and no fade in the DBS_3.3 response could be felt. In group CC (clinical criteria) patients were managed without the use of a nerve stimulator, and the level of neuromuscular block and reversal were evaluated solely on the basis of clinical criteria. In both groups, the TOF ratio was measured by mechanomyography immediately after tracheal extubation. Also, the ability to sustain head lift for 5 s, to protrude the tongue, to open the eyes, and to lift one arm to the opposite shoulder were tested. Results: The TOF ratio, as measured immediately after tracheal extubation, was significantly lower in group CC than in group DBS (means: 0.68 and 0.78, respectively), and the incidence of residual neuromuscular block defined as a TOF ratio <0.7 was significantly higher in group CC than in group DBS (57 and 24%, respectively). The time from the first TOF measurement until the TOF ratio reached 0.8 was significantly longer in group CC than in group DBS (means: 11.5 and 6.2 min, respectively). No significant differences between the two groups of patients were found in duration of anaesthesia, in times from end of surgery to injection of neostigmine, tracheal extubation or TOF ratio 0.8, in dose of pancuronium, or in any other postoperative variable. Conclusion: Routine perioperative manual evaluation of the responses to TOF and DBS_3.3 decreased the incidence and the degree of residual block following the use of pancuronium. It did not, however, exclude clinically significant residual paralysis, nor did it influence the amount of pancuronium used during the operation, the duration of anaesthesia or the time from end of surgery to tracheal extubation or to sufficient recovery of neuromuscular function (TOF=0.8).