Neuromuscular monitoring helps to avoid under-dosing due to factors such as individual differences and diversity of procedure types, especially in elderly patients who are vulnerable to residual neuromuscular blocking agents [11, 12]. Therefore, many anesthesiologists choose to use antagonists at the end of surgery to avoid residual neuromuscular blockade, and the commonly used antagonists are neostigmine and sugammadex. The combination of neostigmine and atropine has been associated with postoperative nausea and vomiting, pneumonia and respiratory failure [13, 14], and although sugammadex are preferred for their advantages [15]. In
Table 2. Relationship between grip strength recovery and TOF ration in patients with different neuromuscular blockers.
|
Patients treated with rocuronium (n=36)
|
Patients treated with cis-atracurium (n=40)
|
P value
|
Maximum grip value, cmH2O
|
213.14±61.07
|
240.90±67.67
|
0.065
|
Mean dose of NMBA, mg
|
53.81±17.50
|
13.65±3.31
|
——
|
Mean maximum grip value recovery
|
|
|
|
0.7TOF ratio %
|
48.20±12.59
|
47.80±11.43
|
0.887
|
0.8TOF ratio %
|
64.18±9.50
|
67.77±9.42
|
0.103
|
0.9TOF ratio %
|
78.67±8.97
|
81.68±7.79
|
0.123
|
Duration of surgery, min
|
144.03±56.79
|
134.73±59.59
|
0.489
|
Duration of PACU stay, min
|
38.97±12.84
|
34.88±14.70
|
0.202
|
Data are expressed as mean ± standard deviation unless otherwise indicated. 95% confidence interval, NMBA=neuromuscular blocking agents,
Table 3. Analysis of grip strength and TOF ration recovery in patients of different genders.
|
male/(n=32)
|
female (n=44)
|
P value
|
Maximum grip value, cmH2O
|
258.72±60.43
|
205.23±60.52
|
0.000
|
Mean maximum grip
value recovery
|
|
|
|
0.7TOF ratio %
|
46.67±10.46
|
48.95±12.90
|
0.414
|
0.8TOF ratio %
|
66.39±8.86
|
65.84±10.14
|
0.806
|
0.9TOF ratio %
|
79.14±8.66
|
81.06±8.30
|
0.322
|
Duration of PACU stay, min
|
37.28±10.04
|
36.48±16.27
|
0.805
|
Data are expressed as mean ± standard deviation unless otherwise indicated. 95% confidence interval.
the absence of quantitative neuromuscular monitoring however, there is uncertainty as to whether an antagonist is required and whether the antagonist dose is fully antagonised.
Therefore, the use of a neuromuscular monitoring device is recommended for better control of the dose and effect of neuromuscular blocking agents and to reduce the occurrence of neuromuscular blocking agents-related complications [4, 19].
The 2018 Expert Consensus states that objective neuromuscular monitoring must be performed whenever non-depolarizing neuromuscular blocking agents are used, and that quantitative monitoring is used to guide the use of non-depolarizing muscle relaxants intraoperatively and to reduce the incidence of residual neuromuscular blockade [4, 5]. The 2021 British Anaesthesia Society guidelines suggest that the use of continuous head elevation, eye opening on exhalation and tongue depressor tests to assess residual neuromuscular blockade is inadequate and that these modalities are only 30%-50% sensitive with a positive predictive value of less than 50% [21-23]. A negative tongue depressor test with a TOF ration of greater than 85% is a good clinical indicator of the waning of neuromuscular blockade, but the presence of a tracheal tube in the mouth of a patient under general anaesthesia makes this method too limited to be used prior to extubation [23]. All patients were found to be able to complete eye opening at around 50% (25% to 80%) of TOF ration, and fist clenching at around 65% of TOF ration [8, 24]. When the TOF ration is less than 70%, extubation will lead to residual neuromuscular blockade after extubation and postoperative complications, such as muscle weakness, decreased oxygen saturation, lung collapse, acute respiratory failure, will significantly increase [25-27]. With a TOF ration of 90% is satisfactory for neuromuscular blockade recovery, complete recovery of extraocular muscle function is still not guaranteed and therefore monitoring of neuromuscular blockade is essential. Although there are many monitoring methods and monitoring sites available [28], for example, Iwasaki H et al. used electromyography to compare the sensitivity of the adductor medialis and the adductor digiti minimi muscles to be similar [29]; Benoît Plaud, M.D. et al. compared the frown and laryngeal adductors to have a longer onset of action but faster recovery than the thumb adductor [30]; Lagneau F et al. monitored the recovery of eyelid and plantar flexors recovered from relaxation faster than the adductors [31]. However, these methods are not currently in widespread use, and a crude assessment using grip strength is one method where quantitative neuromuscular monitoring is not available.
In this study, the grip strength measured with a simple grip strength device increased gradually with increasing TOF ration, the correlation analysis also showed that there was a close correlation between the recovery value of hand grip strength and the TOF ration (R2=0.632). When the TOF ration reaches 90%, it is safe to extubate, and the hand grip strength should be restored to at least 80% of the preoperative value. However, the sample size of this study is small, and the subsequent multi-center large sample study can be conducted to obtain a reliable value for judging the recovery of neuromuscular blockade according to the recovery of grip strength. The method has many shortcomings. Firstly, it cannot be applied to intraoperative monitoring of the depth of neuromuscular blockade and cannot provide a reference for the intraoperative use of neuromuscular blocking agents. Secondly, it must exclude the effect of depth of anaesthesia and needs to be used in conjunction with BIS monitoring, which cannot be used in children or in patients with psychiatric disorders who are unable to co-operate as it requires the patient's subjective will. In the case of the simple grip device, the size of the 50ml syringe is not suitable for patients with relatively small hands, the size of the spring is not suitable for all patients, and the upper pressure limit of the central venous pressure monitoring module on the monitor limits its use, but it can be used as a simple method of monitoring residual neuromuscular blockade in cases where a muscle relaxation monitor is not available. Ultimately it is hoped that this idea will lay the groundwork for a simpler instrument for neuromuscular blockade monitoring.