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October 13, 2018
10/13/2018 1:15:00 PM - 10/13/2018 2:45:00 PM
Room North, Room 21
Determination of Optimal Tof Count at Corrugator Supercilli Muscle to Maintain Deep Neuromuscular Blockade
Yoshifumi Kotake, M.D.,Ph.D., Yuichi Maki, M.D., Daisuke Toyoda, M.D., Risa Abe, M.D., Sayuri Kawahara, M.D., Tatsuo Yamamoto, M.D., Yasumasa Sakamoto, M.D.
Toho University Ohashi Medical Center, Tokyo, Japan
Disclosures: Y. Kotake: Funded Research; Self; Nihon Koden. Consulting Fees; Self; MSD, Nihon Koden, Japan Blood Products, GE Healthcare, Ono Pharmaceuticals, Otsuka Pharmaceutical Laboratory. Y. Maki: None. D. Toyoda: Consulting Fees; Self; Otsuka Pharmaceutical Laboratory. R. Abe: None. S. Kawahara: None. T. Yamamoto: Consulting Fees; Self; Otsuka Pharmaceutical Laboratory. Y. Sakamoto: None.
Background: Deep neuromuscular blockade is typically defined as post-tetanic count at abductor pollicis muscle (PTC-AP) between 1 and 2. Although not universally accepted (Anesth Analg 2015;120:51), several studies suggest that maintaining deep neuromuscular blockade may provide favorable outcome in patients undergoing laparoscopic surgery (Br J Anaesth 2014;112:498, Acta Anaesthesiol Scand 2015;59:434). It is intuitiively clear that objective neuromuscular monitoring is more important during the maintenance and reversal of deep neuromuscular blockade than standard neuromuscular blockade. Unfortunately, monitoring neuromuscular blockade at abductor pollicis muscle is sometimes difficult during laparoscopic surgery. On the contrary, neuromuscular monitoring at corrugator supercilli (CS) is less susceptible to the interference from the setup during laparoscopic procedures. Therefore, it would be clinically relevant if the neuromuscular blockade level as CS can definitely ensure that the PTC-AP is between 1 and 2. However, the relationship between PTC-AP and train-of-four count at corrugator supercilli (TOFC-CS) has been rarely reported. A study by Yamamoto and colleagues demonstrated that twitch height of CS at 10% of control reasonably indicates adequate deep neuromuscular blockade (PTC-AP<6) under sevoflurane anesthesia (Acta Anaesthesiol Scand 2015;59:892). However, the detailed information such as accuracy, sensitivity and specificity of their finding is not currently available. The purpose of this prospective, observational study was to statistically analyze whether TOFC-CS can serve as an alternative to PTC-AP to maintain deep neuromuscular blockade in patients undergoing laparoscopic surgery. Methods: With IRB approval, patient consent and trial registration (UMIN000025007), patients undergoing elective laparoscopic colorectal surgery enrolled in this study. These subjects were anesthetized with propofol and remifentanil supplemented with thoracic epidural block and PTC-AP and TOFC-CS were assessed at every 15 min with accerelometry (TOF Watch SX, MSD). After tracheal intubation with 0.9mg/kg rocuronium, continuous infusion of rocuronium was titrated to maintain PTC-AP between 1 and 2. After the completion of surgery, remaining neuromuscular blockade was antagonized with sugammadex and recovery of TOFR&gt;90% at abductor pollicis was confirmed before extubation. The primary outcome of this study was the area under the curve and best threshold of TOFC-CS to maintain PTC-AP equal to or less than 5 during the maintenance phase. Data were statistically analyzed with R software. Results: Thirty subjects enrolled this study and 397 data sets were available for analysis. The median and IQR of TOFC-CS was 0 (0-1) when PTC-AP was between 1 and 2. The ROC curve and best cut-off value is shown in Figure. The area under the curve of TOFC-CS to maintain PTC-AP equal to or less than 5 was 0.72 and the best threshold of TOFC-CS was 1 with sensitivity and specificity of 81.6% and 59.8%, respectively. Conclusions: Our data suggest TOFC-CS was moderately accurate to maintain deep neuromuscular blockade. This finding was probably related to the relative insensitivity of TOFC compared to PTC at deeper level of neuromuscular blockade. Our data also suggest that to maintain TOFC-CS at 0 will ensure the disappearance of twitch response under total intravenous anesthesia with reasonable accuracy.
Figure 1

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