Relationship of the Train-of-four Fade Ratio to Clinical Signs and Symptoms of Residual Paralysis in Awake Volunteers 

1997 ◽  
Vol 86 (4) ◽  
pp. 765-771 ◽  
Author(s):  
Aaron F. Kopman ◽  
Pamela S. Yee ◽  
George G. Neuman

Background Recovery of the train-of-four (TOF) ratio to a value > 0.70 is synonymous with adequate return of neuromuscular function, but there is little information available concerning the subjective experience that accompanies residual neuromuscular block wherein the TOF ratio is in the range of 0.70 to 0.90. Methods Ten American Society of Anesthesiologists' (ASA) physical status 1 volunteers were studied. Control measurements including grip strength in kilograms and ability to perform a 5-s head- and leg-lift. In addition, a standard wooden tongue depressor was placed between each subject's incisor teeth, and he or she was told not to let the investigator remove it. All subjects were easily able to retain the device despite vigorous attempts to dislodge it. Neuromuscular function was monitored with a Datex (Datex Medical Instrumentation, Inc., Tewksbury, MA) 221 electromyographic (EMG) monitor. TOF stimulation was given every 20 s, and the measured TOF fade ratio was continuously recorded. A 5 mg/kg bolus of mivacurium was then administered, and an infusion at 2 mg.kg-1.min-1 was begun. The infusion was continued until the TOF ratio decreased to < 0.70 and was adjusted to keep it in the range of 0.65 to 0.75. Signs and symptoms of weakness were recorded when the TOF ratio had been stable +/-0.03 for at least 10 min during an interval when there were no adjustments in the infusion. All tests noted previously were repeated at this time. The TOF ratio was then allowed to recover to 0.85-0.90. When stable at this level, all tests were repeated, and the infusion was discontinued. TOF measurements were continued until a ratio of 1.0 was attained and until a final set of observations was recorded. Results The TOF ratio in all subjects was reduced to < 0.70. No volunteers required intervention to maintain a patient airway, and the hemoglobin oxygen saturation while breathing air was > or = 96% at all times. TOF ratios < or = 0.90 were accompanied by diplopia and difficulty in tracking moving objects in all subjects. The ability to strongly oppose the incisor teeth did not return until the TOF ratio (on average) exceeded 0.85. A sustained 5-s head-lift was not achieved until the TOF ratio averaged 0.60 (range, 0.45-0.75). At a TOF ratio of 0.70, grip strength averaged 59% of control (range, 50-75%). With certain exceptions (vision, ability to clench the teeth tightly), there was wide variation in symptomatology between patients for any given TOF ratio. It is impossible to give reliable TOF break-points at which symptoms and signs will be present or absent. Conclusions All subjects had significant signs and symptoms of residual block at a TOF ratio of 0.70; none considered themselves remotely "street ready" at this time. The authors believe that satisfactory recovery of neuromuscular function after mivacurium-induced neuromuscular block requires return of the TOF ratio to a value > 0.90 and ideally to unity.

1996 ◽  
Vol 84 (3) ◽  
pp. 562-565 ◽  
Author(s):  
Olli Erkola ◽  
Pekka Rautoma ◽  
Olli A. Meretoja

Background To ensure rapid recovery of neuromuscular block, it might be useful to administer a short-acting relaxant after a long-acting one. Therefore, the interaction between pancuronium and mivacurium was investigated when mivacurium was administered during the recovery from pancuronium block. Methods After written informed consent, 41 adult patients were studied during propofol/alfentanil/nitrous oxide/oxygen anesthesia. Neuromuscular function was monitored using an electromyographic (EMG) method. AFter a stable EMG calibration response, cumulative doses of pancuronium were given to establish a 95% neuromuscular block. In the control group, and ED95 dose of 100 microg/kg mivacurium was administered instead of pancuronium. When the EMG response after pancuronium or mivacurium had recovered to 25% of the baseline, a single randomized intravenous bolus dose of 10 or 70 microg/kg mivacurium was given. Thereafter, spontaneous recovery of the neuromuscular function was recorded. Results The time from pancuronium until T1 25% EMG recovery was 38 +/- 12 min (mean +/- SD). The respective times after 10 or 70 microg/kg mivacurium were 28 +/- 8 and 54 +/- 7 min in the pancuronium group or 3 +/- 1 (n=3) and 10 +/- 4 min in the mivacurium group (P=0.0001). Times to 95% EMG recovery after 10 or 70 microgm/kg mivacurium were 77 +/- 14 and 97 +/- 16 min in the pancuronium group and 11 +/- 3 and 20 +/- 7 min in the mivacurium group, respectively (P<0.0001). Recovery indexes after 10 or 70 microg/kg mivacurium group, respectively (P<0.0001). Recovery indexes after 10 or 70 microg/kg mivacurium wre 26 +/- 4 and 22 +/- 6 min in the pancuronium group or 7 +/- 3 (n=3) and 5+/- 2 min in the mivacurium group, respectively (P<0.0001). Times from the administration of 10 or 70 microg/kg mivacurium until train-of-four ration 0.7 were 94 +/- 16 and 111 +/- 14 min in the pancuronium group and 12 +/- 4 and 22 +/- 8 min in the mivacurium group, respectively (P<0.0001). Conclusions After pancuronium, mivacurium is not a short acting neuromusclar blocking agent.


2002 ◽  
Vol 96 (3) ◽  
pp. 583-587 ◽  
Author(s):  
Aaron F. Kopman ◽  
Monika M. Klewicka ◽  
George G. Neuman

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.


2017 ◽  
Vol 127 (3) ◽  
pp. 441-449 ◽  
Author(s):  
László Asztalos ◽  
Zoltán Szabó-Maák ◽  
András Gajdos ◽  
Réka Nemes ◽  
Adrienn Pongrácz ◽  
...  

Abstract Background Rocuronium-induced neuromuscular block that spontaneously recovered to a train-of-four count of four can be reversed with sugammadex 0.5 or 1.0 mg/kg. We investigated whether these doses of sugammadex can also reverse vecuronium at a similar level of block. Methods Sixty-five patients were randomly assigned, and 64 were analyzed in this controlled, superiority study. Participants received general anesthesia with propofol, sevoflurane, fentanyl, and vecuronium. Measurement of neuromuscular function was performed with acceleromyography (TOF-Watch-SX, Organon Teknika B.V., The Netherlands ). Once the block recovered spontaneously to four twitches in response to train-of-four stimulation, patients were randomly assigned to receive sugammadex 0.5, 1.0, or 2.0 mg/kg; neostigmine 0.05 mg/kg; or placebo. Time from study drug injection to normalized train-of-four ratio 0.9 and the incidence of incomplete reversal within 30 min were the primary outcome variables. Secondary outcome was the incidence of reparalysis (normalized train-of-four ratio less than 0.9). Results Sugammadex, in doses of 1.0 and 2.0 mg/kg, reversed a threshold train-of-four count of four to normalized train-of-four ratio of 0.9 or higher in all patients in 4.4 ± 2.3 min (mean ± SD) and 2.6 ± 1.6 min, respectively. Sugammadex 0.5 mg/kg reversed the block in 6.8 ± 4.1 min in 70% of patients (P < 0.0001 vs. 1.0 and 2.0 mg/kg), whereas neostigmine produced reversal in 11.3 ± 9.7 min in 77% of patients (P > 0.05 vs. sugammadex 0.5 mg/kg). The overall frequency of reparalysis was 18.7%, but this incidence varied from group to group. Conclusions Sugammadex 1.0 mg/kg, unlike 0.5 mg/kg, properly reversed a threshold train-of-four count of four vecuronium-induced block but did not prevent reparalysis.


2003 ◽  
Vol 98 (5) ◽  
pp. 1278-1280 ◽  
Author(s):  
Srinivasa N. Raja ◽  
Hassan H. Ali

This study was undertaken to compare the sensitivities of the train-of-four response (2 Hz for 2 s), the single twitch (0.15 Hz), and the tetanic response (50 Hz for 5 s) as indices of residual nondepolarizing block. Spontaneous or induced recovery of evoked thumb adduction in response to ulnar nerve stimulation was studied. One hundred and seven adult surgical patients were divided according to the relaxant used, into six groups. We found that when the single twitch recovered to control height, the train-of-four ratio was well below 1.0. This ratio was significantly lower during spontaneous recovery than following neostigmine antagonism of the block (P < 0.01). The tetanic response was fully sustained when the train-of-four ratio was above 0.7. When the ratio was less than 0.7, variable degrees of fade of tetanus were evident. Analysis of variance indicated similar train-of-four ratios among the six groups at complete recovery of the single twitch irrespective of the relaxant technique used (P < 0.1). It is concluded that a train-of-four ratio of 0.7 or higher reliably indicates the recovery of the single twitch to control height and a sustained response to tetanic stimulation at 50 Hz for 5 s. The clinical significance of this study is as follows: the train-of-four response provides the same indication of clinical recovery from nondepolarizing block as obtained from tetanic stimulation at a physiological frequency; and reliance on the recovery of the single twitch to control height as a criterion of spontaneous return to normal clinical neuromuscular function may be misleading.


2020 ◽  
Vol 187 (5) ◽  
pp. e33-e33
Author(s):  
Keila K Ida ◽  
Anne Sophie Van-Wijnsberghe ◽  
Alexandru Tutunaru ◽  
Véronique Limpens ◽  
Aurélie Sauvage ◽  
...  

BackgroundThis retrospective study assessed the onset and duration of the neuromuscular block (NMB) induced by cis-atracurium 0.15 mg/kg intravenously with and without fentanyl or lidocaine infusions in 45 isoflurane-anaesthetised dogs.MethodsDogs with neuromuscular function assessed by a calibrated train-of-four (TOF) monitor with stimulation (every 13 s) of the peroneal nerve were included. The onset and duration of the NMB were defined as the time from cis-atracurium administration until TOF=0 and the time during TOF=0 display, respectively.ResultsThe NMB onset was shorter during fentanyl (mean±sd) (1.9±0.7 minutes; P=0.0042) and lidocaine (2.0±0.7 minutes; P=0.0154) compared with control (2.9±0.8 minutes). The NMB duration was shorter in the fentanyl (27.5±7.3 minutes; P=0.0491), but not in the lidocaine group (32.3±6.9 minutes; P=0.0790), compared with control (33.7±9.1 minutes). The NMB onset was poorly but significantly correlated with the dose of fentanyl and lidocaine administered before cis-atracurium (r=−0.3396; P=0.0225). The fentanyl and lidocaine groups received more crystalloid and colloid boluses than the control.ConclusionsFentanyl and lidocaine shortened the NMB onset and the former decreased the NMB duration. Further prospective studies are required to clarify whether this was associated with an indirect decrease in blood pressure or a direct interaction between cis-atracurium and fentanyl and lidocaine.


2010 ◽  
Vol 113 (4) ◽  
pp. 825-832 ◽  
Author(s):  
Tom Heier ◽  
James E. Caldwell ◽  
John R. Feiner ◽  
Luke Liu ◽  
Theresa Ward ◽  
...  

Background Baseline acceleromyographic adductor pollicis train-of-four (TOF) ratio varies significantly between individuals and is often greater than unity. Thus, normalization of acceleromyography data is necessary. The relationship between normalized acceleromyographic TOF ratio, lung volumes, and clinical signs of residual neuromuscular block was studied. Methods In 12 healthy volunteers, three steady-state levels of neuromuscular block were achieved with mivacurium infusions. TOF ratio was measured acceleromyographically at the adductor pollicis using a preload. Lung volume measurements and a series of clinical tests were made at each stable block and reconciled to the normalized TOF measures. Results None experienced airway obstruction or arterial oxygen desaturation, even at normalized TOF ratio less than 0.4. Functional residual capacity remained unchanged whereas vital capacity decreased linearly with decreasing TOF ratio. The ability to protrude the tongue was preserved at all times. The ability to clench the teeth was lost in one volunteer at normalized TOF ratio of 0.84 but retained in four at normalized TOF ratio less than 0.4. Four volunteers lost the ability both to raise the head more than 5 s and to swallow, with the most sensitive individual demonstrating these effects at normalized TOF ratio of 0.60. At mean normalized TOF ratio of 0.42, the mean handgrip strength was approximately 20% of baseline value. Conclusion Lung vital capacity decreased linearly with decreasing TOF ratio. Responses to clinical tests of muscle function varied to a large extent among individuals at comparable TOF ratios. None of the volunteers had significant clinical effects of neuromuscular block at normalized acceleromyographic TOF ratio greater than 0.90.


2016 ◽  
Vol 12 (3) ◽  
Author(s):  
Ann Tammelin

Swedish nursing homes are obliged to have a management system for systematic quality work including self-monitoring of which surveillance of infections is one part. The Department of Infection Control in Stockholm County Council has provided a simple system for infection surveillance to the nursing homes in Stockholm County since 2002. A form is filled in by registered nurses in the nursing homes at each episode of infection among the residents. A bacterial infection is defined by antibiotic prescribing and a viral infection by clinical signs and symptoms. Yearly reports of numbers of infections in each nursing home and calculated normalized figures for incidence, i.e. infections per 100 residents per year, as well as proportion of residents with urinary catheter are delivered to the medically responsible nurses in each municipality by the Department of Infection Control. Number of included residents has varied from 4,531 in 2005 to 8,157 in 2014 with a peak of 10,051 in 2009. The yearly incidences during 2005 - 2014 (cases per 100 residents) were: Urinary tract infection (UTI) 7.9-16.0, Pneumonia 3.7-5.3, Infection of chronic ulcer 3.4–6.8, Other infection in skin or soft tissue 1.4–2.9, Clostridium difficile-infection 0.2–0.7, Influenza 0–0.4 and Viral gastroenteritis 1.2–3.7. About 1 % of the residents have a suprapubic urinary catheter, 6–7 % have an indwelling urinary catheter. Knowledge about the incidence of UTI has contributed to the decrease of this infection both in residents with and without urinary catheter.


Healthcare ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 498
Author(s):  
Mark Reinwald ◽  
Peter Markus Deckert ◽  
Oliver Ritter ◽  
Henrike Andresen ◽  
Andreas G. Schreyer ◽  
...  

(1) Background: Healthcare workers (HCWs) are prone to intensified exposure to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in the ongoing pandemic. We prospectively analyzed the prevalence of antibodies against SARS-CoV-2 in HCWs at baseline and follow up with regard to clinical signs and symptoms in two university hospitals in Brandenburg, Germany. (2) Methods: Screening for anti-SARS-CoV-2 IgA and IgG antibodies was offered to HCWs at baseline and follow up two months thereafter in two hospitals of Brandenburg Medical School during the first wave of the COVID-19 pandemic in Germany in an ongoing observational cohort study. Medical history and signs and symptoms were recorded by questionnaires and analyzed. (3) Results: Baseline seroprevalence of anti-SARS-CoV-2 IgA was 11.7% and increased to 15% at follow up, whereas IgG seropositivity was 2.1% at baseline and 2.2% at follow up. The rate of asymptomatic seropositive cases was 39.5%. Symptoms were not associated with general seropositivity for anti-SARS-CoV-2; however, class switch from IgA to IgG was associated with increased symptom burden. (4) Conclusions: The seroprevalence of antibodies against SARS-CoV-2 was low in HCWs but higher compared to population data and increased over time. Screening for antibodies detected a significant proportion of seropositive participants cases without symptoms.


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