Recovery of early postoperative muscle strength after deep neuromuscular block by means of ultrasonography with comparison of neostigmine versus sugammadex as reversal drugs: study protocol for a randomised controlled trial

Abstract

Introduction: Despite the use of quantitative neuromuscular monitoring together with the administration of reversal drugs (neostigmine or sugammadex), the incidence of residual neuromuscular blockade defined as a train-of-four ratio (TOFr) <0.9 remains high. Even TOFr >0.9 cannot ensure adequate recovery of neuromuscular function when T1 height is not recovered completely. Thus, a mathematical correction of TOFr needs to be applied because the return of a normal TOFr can precede the return of a normal T1 twitch height. On the other hand, different muscles have different sensitivities to neuromuscular blockade agents; thus, complete recovery of one specific muscle group does not represent complete recovery of all other muscles. Therefore, our study aims to assess the muscle strength recovery of respiratory-related muscle groups by ultrasound and evaluate global strength using handgrip dynamometry in the early postoperative period when TOFr=0.9 and corrected TOFr (cTOFr)=0.9 with comparison of neostigmine versus sugammadex as reversal drugs.

Methods and analysis: This study will be a prospective, single-blinded, randomised controlled trial involving 60 patients with American Society of Anesthesiologists physical status I-II and aged between 18 and 65 years, who will undergo microlaryngeal surgery. We will assess geniohyoid muscle, parasternal intercostal muscle, diaphragm, abdominal wall muscle and handgrip strength at four time points: before anaesthesia, TOFr=0.9, cTOFr=0.9 and 30 min after admission to the post anaesthesia care unit. Our primary objective will be to compare the effects of neostigmine and sugammadex on the recovery of muscle strength of different muscle groups in the early postoperative period when TOFr=0.9 and cTOFr=0.9. The secondary objective will be to observe the difference of muscle strength between the time points of TOFr=0.9 and cTOFr=0.9 to find out the clinical significance of cTOFr >0.9.

Ethics and dissemination: The protocol was reviewed and approved by the Ethics Committee of The First Affiliated Hospital, Sun Yat-sen University. The findings will be disseminated to the public through peer-reviewed scientific journals.

Trial registration number: ChiCTR2000033832.

Keywords: adult anaesthesia; clinical trials; ultrasonography.

Figure 1

Reversal with neostigmine after cisatracurium-induced non-depolarising neuromuscular blockade. When the TOFr reaches a value of 92% (red dotted line), the T1 twitch height reaches only 33% and T4 twitch height reaches 30% of control. TOFr, train-of-four ratio.

Figure 2

Reversal with neostigmine after cisatracurium-induced non-depolarising neuromuscular blockade. When the T1 twitch height reaches 91% of control, the TOFr still be depressed as 73% (red dotted line). TOFr, train-of-four ratio.

Figure 3

Submental ultrasonographic evaluation and hyoid bone displacement on a model. (A) A vertical line is drawn from superior thyroid notch to mandible for probe placement. (B) Probe is placed at midsagittal plane of submental area. The mandible and the hyoid bone (C) at rest and (D) during swallowing. White arrow represents shadow behind the mandible; green arrow represents shadow behind the hyoid bone; asterisk represents geniohyoid muscle.

Figure 4

Ultrasound of the right parasternal intercostal muscle on a model. (A) Probe is positioned in cranio-caudal direction at the second intercostal space approximately 2–3 cm lateral to the sternal edge. (B) Using B-mode the parasternal intercostal muscle is identified as a three-layered biconcave structure: two linear hyperechoic membranes, respectively, running from the anterior and posterior aspects of the adjoining ribs, and a medial portion with muscle echotexture. (C) Using M-mode, the thickness of the parasternal intercostal muscle will be measured on frozen images.

Figure 5

Ultrasound of diaphragm on a model. (A) Probe position for diaphragmatic excursion measurements with C5-1s convex transducer. Black arrow indicates the costal margin. (B) B-mode diaphragm sonography. (C) M-mode diaphragm sonography. White arrows indicate the beginning (left) and the end (right) of the diaphragmatic contraction.

Figure 6

Ultrasound imaging of the lateral abdominal wall muscles on a model (A) taken during resting state, (B) taken during cough. (C) Probe is positioned perpendicular to the abdominal wall. Probe position for abdominal muscle sonography with L14-6Ns liner transducer. EO, external oblique; IO, internal oblique; TrA, transversus abdominis.

Figure 7

Study flow diagram. PACU, post anaesthesia care unit; TOFr, train-of-four ratio.