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。     

Comparison of double-burst and train-of-four stimulation to assess neuromuscular blockade in children

Double-burst stimulation (DBS), a new technique to evaluate neuromuscular function, consists of two 50-Hz trains of 60-ms duration and 750 ms apart. DBS was compared with train-of-four (TOF) stimulation in 21 children aged 3-10 yr, during halothane anesthesia. On one arm the ulnar nerve was stimulated supramaximally with TOF stimulation every 12 s and the force of the evoked contraction of the adductor pollicis measured with an FTO3 force transducer and recorded on paper. Atracurium (0.4-0.5 mg.kg-1) was administered. During recovery from neuromuscular blockade, TOF stimulation was interrupted periodically and DBS substituted. The same stimulation patterns were applied to the ulnar nerve of the other arm simultaneously, and the clinical anesthesiologist was asked to estimate the degree of fade with both. There was good correlation between the measured TOF ratio (ratio of fourth to first response) and DBS ratio (ratio of second to first response). The TOF and DBS ratios above which fade could no longer be appreciated manually were (mean +/- SEM) 0.44 +/- 0.03 and 0.67 +/- 0.04 (P = 0.0002). Corresponding ranges were 0.3-0.8 for TOF and 0.4-0.9 for DBS, but DBS fade was always apparent if TOF fade could be detected. Therefore, in children, DBS is more sensitive than is TOF stimulation for the clinical assessment of recovery from neuromuscular blockade.     

Response to double-burst appears before response to train-of-four stimulation during recovery from non-depolarizing neuromuscular blockade

Background: Double-burst stimulation (DBS) it a relatively new nerve stimulation mode introduced for improved manual detection of residual neuromuscular blockade. Previous studies have shown that DBS_{3,3 50/50} (3 stimuli at 50 Hz followed 0.75 seconds later by 3 stimuli at 50 Hz) can detect deeper degrees of neuromuscular blockade than train-of-four (TOF) stimulation.
Aim: The aim of the present study was to examine if DBS_{3,3 80/40} (3 stimuli at 80 Hz followed 0.750 s later by 3 stimuli at 40 Hz) can detect even deeper degrees of neuromuscular blockade than DBS_{3,3 50/50} and to determine the time lapse from reappearance of response to each of the two DBS modes until reappearance of response to the TOF mode of nerve stimulation.
Methods: The study comprised 20 women undergoing gynaecological surgery and anaesthetised with fentanyl, thiopentone, halothane, and nitrous oxide. Neuromuscular transmission was monitored by using mechanomyography and stimulation of the ulnar nerve. Atracurium was used for neuromuscular blockade.
Results: Elapsed time from reappearance of response to DBS_{3,3 80/40} and DBS_{3,3 50/50} to reappearance of response to TOF stimulation was 459±196 (mean±SD) and 360±150 seconds, respectively, ( P <0.05).
Conclusions: DBS_{3,3 80/40} is capable of detecting deeper degrees of blockade than DBS_{3,3 50/50} which again is capable of detecting deeper degrees of blockade than TOF.     

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.     

Frequency of train-of-four stimulation influences neuromuscular response

We have compared the effects of two different frequencies oftrain-of-four stimulation of the ulnar nerve (2-Hz stimulationonce every 10 or 20 s) on onset time and potency of atracurium,vecuronium and mivacurium during balanced anaesthesia. The adductorpollicis EMG was recorded simultaneously in both hands of 24children aged 2–12 yr. After administration of an ED₅₀dose of each blocker, onset times were mean 21 (SEM 10) s shorter(P<0.05) and decreases in neuromuscular function were 22(3)% greater (P<0.001) in the hand which was stimulated onceevery 10 s. We conclude that it is not possible to compare potencyestimates of neuromuscular blocking agents if different stimulationpatterns have been used.     

Subjective responses to train-of-four and double burst stimulation in awake patients

The present study was undertaken to determine whether the discomfort associated with the sequential bursts of stimuli comprising the two recommended forms of double burst stimulation (DBS) is comparable to that associated with the repetitive stimuli of train-of-four (TOF). Twenty-one unmedicated volunteers rated on a visual analog scale the discomfort associated with randomly applied DBS and TOF stimulations at 20, 30 and 50 mA. All participants were blinded to the mode of stimulation, as well as to the current intensity. At each amperage tested, TOF produced significantly less discomfort than either form of DBS (P less than 0.01). Stimulation at 50 mA produced median visual analog scale scores of 7.5, 7.0, and 5.0 for DBS3,2, DBS3,3, and TOF, respectively. At 30 mA the corresponding median visual analog scale scores were 4.5, 5.5, and 3.0, whereas at 20 mA the scores were 4.0, 4.5, and 2.0, respectively. Thus, DBS is more uncomfortable than TOF at each current tested; however, in light of reports of its higher sensitivity, DBS may be the preferred means of assessing neuromuscular function in the awake as well as the anesthetized patient when a force transducer and recorder are not readily available.     

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.     

Does perioperative tactile evaluation of the train-of-four response influence the frequency of postoperative residual neuromuscular blockade?

The authors conducted a randomized controlled clinical trial to evaluate the usefulness of perioperative manual evaluation of the response to train-of-four (TOF) nerve stimulation. A total of 80 patients were divided into four groups of 20 each. For two groups (one given vecuronium and one pancuronium), the anesthetists assessed the degree of neuromuscular blockade during operation and during recovery from neuromuscular blockade by manual evaluation of the response to TOF nerve stimulation. In the other two groups, one of which received vecuronium and the other pancuronium, the anesthetists evaluated the degree of neuromuscular blockade solely by clinical criteria. The use of a nerve stimulator was found to have no effect on the dose of relaxant given during anesthesia, on the need for supplementary doses of anticholinesterase in the recovery room, on the time from end of surgery to end of anesthesia, or on the incidence of postoperative residual neuromuscular blockade evaluated clinically. The median (and range of) TOF ratios recorded in the recovery room were 0.75 (0.33-0.96) and 0.79 (0.10-0.97) in the vecuronium groups monitored with and without a nerve stimulator, respectively. These ratios were significantly higher than those found in the pancuronium groups, which wre 0.66 (0.06-0.90) and 0.63 (0.29-0.95), respectively. However, no difference was found between the vecuronium and pancuronium groups in the number of patients showing clinical signs of residual neuromuscular blockade, as evaluated by the 5-s head-lift test.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationship of train-of-four ratio to twitch depression during pancuronium-induced neuromuscular blockade

The relationship of train-of-four (TOF) ratio to the depression of the first twitch (TD) was investigated in 16 patients given pancuronium in doses insufficient to eliminate the fourth response in the train. In ten patients the block was allowed to spontaneously recover (Group 1) and in six it was reversed with neostigmine (Group 2) once maximum depression of TOF ratio had occurred. Maximum depression of the first response occurred in 6.5 +/- 4.3 min (mean +/- SD). Maximum depression of the TOF ratio was not present until 28.0 +/- 11.0 min. TOF ratio was usually still decreasing when recovery of TD had begun. However, once the TOF ratio began to recover, the recovery rates for TD and TOF ratio were similar in both the spontaneously recovering and the reversed groups. TOF ratio at complete TD recovery was 74.9 +/- 15.7 and 86.2 +/- 15.4% for the two groups. A kinetic analysis yielded significantly different elimination rate constants for the two effects from the "effect compartment." These findings suggest that these two effects of pancuronium are exerted at different sites.     

Post-tetanic burst count: A stimulating pattern for profound neuromuscular blockade

The purpose of this study was to compare the pattern of recovery from vecuronium 0.07 mg · kg^?1 induced neuromuscular blockade using post-tetanic burst count (PTBC)-(three short tetanic bursts of 0.2 msec duration every 20 msec given every second following a tetanus), and post-tetanic count (PTC)-(0.2 msec single twitch stimuli given every second following a tetanus) using an accelerometer in 60 adult patients during nitrous oxide-oxygen-isoflurane anaesthesia. In addition, the relationship among PTBC, PTC, and T_-1 (the 1st response in the train-of-four (TOF) stimulation) was examined to investigate whether the PTBC had an advantage over the PTC or TOF for evaluating intense neuromuscular blockade. The PTBC was greater than PTC during the 15–35 min after the administration of vecuronium (unpaired t test with Bonferroni’s correction, P < 0.05). Time to the return of PTB response was shorter than that of PTT (17.7 ± 3.2 vs 22.7 ± 3.7 min, unpaired t test, P = 0.0005). Time from the return of PTB to that of T_-1 was longer than the time from the return of PTC to that of T_-1 (13.3 ± 2.6 vs 9.2 ± 2.8 min, unpaired t test, P = 0.0003). At the return of T_-1, PTBC was greater than PTC (14.3 ± 6.9 vs 9.4 ± 2.3, unpaired t test, P = 0.0153). These results suggest that, using PTBC, a more profound level of neuromuscular blockade can be evaluated than that using PTC.     

Electrical and mechanical train-of-four responses during depolarizing and nondepolarizing neuromuscular blockade

Simultaneous measurements of train-of-four (TOF) responses by integrated electromyography (IEMG) and twitch force were compared for atracurium, vecuronium, and succinylcholine in 30 subjects during nitrous oxide-fentanyl anesthesia. Determinations of TOF were made during neuromuscular blockade (NMB) onset and recovery. Scattergrams and least squares regression lines were plotted, and z-tests for parallel slope and common intercept were used to compare lines. Data for atracurium and vecuronium were indistinguishable in all groups (z less than 0.05), and therefore pooled to represent nondepolarizing blockade. During onset of nondepolarizing NMB, TOF showed a linear relationship indistinguishable from the line of identity (slope 0.93, intercept -0.06, z less than 0.05). During recovery the intercept was unchanged (z greater than 0.05), but the slope was significantly changed, indicating mechanical TOF lags behind IEMG during recovery. This finding is important for interpretation of IEMG when used for clinical monitoring. Comparison of data for depolarizing NMB shows more complex relationships. Integrated electromyography is found to be convenient and reliable for monitoring nondepolarizing NMB.     

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.     

Relationship between posttetanic count and response to carinal stimulation during vecuronium-induced neuromuscular blockade

The correlation between degree of peripheral neuromuscular blockade and response to carinal stimulation was evaluated in two groups of 25 patients: one group was anaesthetized with thiopental, N2O and halothane, and the other group received thiopental, N2O and fentanyl. The degree of peripheral blockade was evaluated using train-of-four (TOF) and posttetanic twitch (PTC) stimulation of the ulnar nerve. The degree of diaphragmatic paralysis was evaluated indirectly by stimulating the carina and observing the corresponding muscular response, which was graded as severe, mild or absent. During halothane anaesthesia a PTC of 0 always indicated that no response to carinal stimulation could be elicited. On the appearance of the first response to posttetanic twitch stimulation (PTC = 1), 2% of the patients showed a mild response to carinal stimulation. At the first response to TOF stimulation, 48% of the patients reacted with a mild response. During thiopental, N2O, fentanyl anaesthesia one of 25 patients showed a mild response to carinal stimulation at a PTC of 0. When PTC was 1, 20% of the patients reacted mildly to the stimulation. At the first response to TOF stimulation, 92% showed a response to carinal stimulation; 24% of these responses were severe, necessitating intervention. It is concluded that the TOF response elicited peripherally is a late sign of neuromuscular recovery of the diaphragm, and that the method of counting posttetanic twitches is superior to the TOF response in evaluating early recovery of this muscle. Further, to ensure total diaphragmatic paralysis, the neuromuscular blockade of the peripheral muscles should be so intense that no response to posttetanic twitch stimulation (PTC = 0) can be elicited.     

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.     

深度肌松和中度肌松在单孔腹腔镜全子宫切除术中的比较

目的 比较术中维持深度肌松和中度肌松在单孔腹腔镜全子宫切除术中的应用效果.方法 选择2020年6—10月择期在全凭静脉麻醉下行单孔腹腔镜全子宫切除术的患者61例,年龄45～62岁,BMI 17～28 kg/m2,ASAⅡ或Ⅲ级.采用随机数字表法将患者分为两组:深度肌松组(n=31)和中度肌松组(n=30).深度肌松组麻...     

A close relationship between post-tetanic twitch and train-of-four responses during neuromuscular blockade by vecuronium

The relationship between post-tetanic twitch (PTT) and train-of-four (TOF) responses after intravenous administration of vecuronium were studied using EMG in 20 patients under nitrous oxide and enflurane anesthesia. After the initial dose (0.2mg·kg^–1) of vecuronium, the detectable first twitch of PTT (PTT₁) always preceded that of TOF (TOF₁) with the mean time interval of 10.7 ± 2.6min. The post-tetanic count (PTC) which coincided with the first appearance of TOF₁ was 9.4 ± 2.6. After the appearance of TOF₁, the magnitude of TOF₁ was almost identical to that of PTC₁₀ until full recovery from neuromuscular blockade was observed, whether the supplemental doses of vecuronium (0.03–0.04mg·kg^–1 i.v.) were administered or not. The magnitude of TOF₂ was slightly lower than that of PTC₂₀. These results suggest that there is a close relationship between these two types of response, and by evaluating not only PTC but also the magnitude of each PTT, the recovery of TOF responses can be predicted and its extent be estimated fairly accurately.(Toyooka H, Noguchi Y, Ebata T, et al.: A close relationship between post-tetanic twitch and train-of-four responses during neuromuscular blockade by vecuronium. J Anesth 5: 146–152, 1991)     

The relationship of posttetanic count and train-of-four responses during recovery from intense cisatracurium-induced neuromuscular blockade

Posttetanic count (PTC) has been used to quantify intense degrees of nondepolarizing neuromuscular blockade. Our objective in the present investigation was to discern whether PTC correlates with recovery from intense cisatracurium-induced neuromuscular blockade under both inhaled and IV anesthesia. In 60 patients, anesthesia was induced with propofol 2 mg/kg and fentanyl 1.5 micro g/kg IV. Recovery from intense neuromuscular blockade induced by cisatracurium (0.15 mg/kg) was studied in 2 groups. Group 1 (n = 30) had anesthesia maintained with propofol 100-200 micro g x kg(-1) x min(-1) and 60% N(2)O in O(2), whereas Group 2 (n = 30) had anesthesia maintained with isoflurane (end-tidal concentration 0.8%) and 60% N(2)O in O(2). Neuromuscular functions were monitored using acceleromyography. Cycles of posttetanic stimulation were repeated every 6 min with train-of-four (TOF) stimulation in between. Measurement included times to posttetanic responses and to the first response to TOF stimulation (T(1)), as well as the correlation between PTC and T(1). In Group 1, the mean times to PTC(1) and T(1) were 35.6 +/- 7.5 and 46.9 +/- 6.5 min, respectively. Corresponding times in Group 2 were 39.5 +/- 6.8 and 56.7 +/- 5.4 min, respectively. There was a good time correlation, r = 0.919 for propofol (Group 1) and r = 0.779 for isoflurane (Group 2), between PTC and T(1) recovery in both groups. The PTC when T(1) appeared ranged between 8 and 9 in Group 1 and 8 and 14 in Group 2. Conforming to original observations with other neuromuscular blocking drugs, there is a correlation between PTC and TOF recovery from intense cisatracurium-induced neuromuscular blockade allowing better monitoring of this intense degree of blockade during both IV (propofol) and isoflurane anesthesia. IMPLICATIONS: Monitoring posttetanic count during intense neuromuscular blockade allows the clinician to estimate the intensity of the blockade and estimate recovery time. The relationship between posttetanic count and train-of-four recovery from intense cisatracurium-induced neuromuscular blockade was documented under both IV and inhaled anesthesia.     

Acceleromyography vs. electromyography: an ipsilateral comparison of the indirectly evoked neuromuscular response to train-of-four stimulation

BACKGROUND: There is a considerable body of evidence which suggests that data obtained using acceleromyography (AMG) cannot be used interchangeably with observations obtained by mechanomyographic (MMG) or electromyograhic (EMG) methods. All previous such studies evaluated the responses from contralateral limbs. This investigation was undertaken to determine if these previously described differences were in part a function of observing the responses from opposing limbs. METHODS: We compared the ipsilateral EMG and AMG response to an ED(95) bolus of atracurium in 50 subjects. In half of the individuals the thumb was free to move freely; in half, a small elastic preload was applied to the thumb. Train-of-four (TOF) recovery was followed until a TOF ratio >0.90 was recorded by both monitors. Acceleromyography vs. EMG differences and the resultant 95% confidence limits for twitch height (T1) and the TOF ratio were determined. RESULTS: When the AMG TOF value had recovered to a value of 0.72 +/- 0.03; the simultaneously evoked EMG value averaged only 0.59 +/- 0.08. This difference was statistically significant (P < 0.001). Although the mean difference AMG vs. EMG was little more than 0.10, differences in an individual might be twice that amount. When the AMG TOF value had recovered to 0.90, the simultaneously evoked EMG value averaged 0.85. Again the 95% confidence limits for individual observations was very wide. With EMG, once the TOF ratio returns to a value of 0.70, T1 has returned to 95% of control. In contrast with AMG, return of T1 -95% of control requires a TOF ratio of almost 0.90. Addition of an elastic preload to the thumb decreased control TOF variability without effecting the relationship between twitch height and the TOF ratio. CONCLUSION: Acceleromyographic TOF values tend to overestimate the extent of EMG recovery. Acceleromyographic TOF values <0.90 are indicative of incomplete neuromuscular recovery.