IN REPLY.

IN REPLY: Sir, the author agrees with the opinion raised by Dr. Choi et al. However, they misunderstood several aspects of our case. Below we have addressed the points raised in his correspondence.

First, in this case, the post-tetanic count (PTC) was assessed after confirming the absence of response of train-of-four (TOF) stimulation which indicates that the neuromuscular block (NMB) level of the patient was in a deep block. According to the suggestion of ideal neuromuscular monitoring, PTC should be assessed as soon as train-of-four count (TOFc) becomes 0 [1]. And this sequence should be repeated with time interval with more than 3–4 min until TOFc becomes more than 0 for the accurate neuromuscular monitoring and avoiding measurements during post-tetanic potentiation. We followed this sequence during the recovery of the neuromuscular blockade of the patient.

Second, as mentioned in the original report, it was regrettable that we did not use an adequate dose of sugammadex at first administration. In the case of deep NMB, sugammadex 4 mg/kg is advised for the reversal [2]. Thus, at least 300 mg of sugammadex should be used in this patient (75 kg of body weight) at the first use. However, we noticed that an inadequate dose of sugammadex was used and administered additional sugammadex 200 mg.

Third, we used sugammadex in spite of profound bradycardia because we did not notice the bradycardia was developed by sugammadex. The bradycardia lasted only about 10s without hypotension and returned to normal spontaneously. Most cases of bradycardia associated with sugammadex were clinically insignificant or easily treatable at the time of its first release [3]. However, only a few cases of severe bradycardia with the use of sugammadex was reported recently. Thus, we did not recognize the risk of bradycardia after the use of sugammadex [4]. As Dr. Choi et al. mentioned, it would be reasonable and safer to use anticholinesterase or waiting for the natural recovery from NMB.

Reports about the unknown complications associated with sugammadex are increasing as its widespread use [5]. This case reported profound bradycardia and resistance to the sugammadex after the use of excessive doses of sugammadex. The author emphasizes that we should be aware of the possibility of severe complications after the use of sugammadex and proper dosage of sugammadex should be used based on the quantitative neuromuscular monitoring.