Brief overview of the paper and its main findings Answers to the reviewer comments are almost satisfied. I think insufficient correction for some points. I want to ask to authors for the following three points again.

1. The first one is the answer to reviewer 1's comment. comment Authors administered midazolam for premedication. Which injection did authors choose IM or IV? Effective time is different between IM and IV. In my opinion, duration of midazolam is important for this report. answer As referee suggested, we have added how to administered midazolam. “However, we decided to decrease the dose of intravenous administration of midazolam to 0.5 mg, to minimize the risk of unpredictable changes in respiratory function.” But still there is the following paragraph in text. Second episode (Fig.2) Several weeks later, the same patient was scheduled for dental treatment under monitored anesthesia care with spontaneous breathing plus regional anesthesia. We induced and maintained anesthesia for one hour with a target controlled infusion of propofol (TCI level = 1.1~1.2 μg/ml) after midazolam (1 mg) premedication.

2. The second point is answer to reviewer 2's comment. comment

. Though some cases with post-hyperventilation apnea may recover

spontaneously in a short time, please comment on a timing of performance of respiratory assistance using a bag and mask in post-hyperventilation apnea. answer As referee suggested, we have added sentence to explain timing of usage of bag-valve-mask by our team. “During root canal treatment for an infected, non-vital lower second molar, the patient started hyperventilation attack after experiencing pain. Since fifteen minutes of therapeutic treatment using the rebreathing method with a paper bag did not alleviate her symptoms, our team of dental anesthesiologist was asked to support her respiratory condition.” The authors have described artificial ventilation timing at the time of the first attack, however, I think reviewer2 requested a general description for timing of bag mask ventilation. Although, if there is no additional comments from the reviewer2 there are no need for change.

3. Parentheses have been frequently used as follows. I want to erase of these if possible.

A 17-year-old female (height 154 cm, weight 56.4 kg) Dental treatment (root canal treatment for an infected lower second molar) benzodiazepines (alprazolam) confirming sustained hyperventilation (respiratory rate 50~60 breaths/minute) with desaturation to 92% (blood pressure 130/83 mmHg, pulse rate 115 beats/minute), low dose oxygen supplementation (2 l/min) a higher level of oxygen (5~7 l/min). Two minutes after continuous mask ventilation (8~10 counts/min) target controlled infusion of propofol (TCI level = 1.1~1.2 μg/ml) after midazolam (1 mg) post-hyperventilation apnea (with desaturation to 86%) TCI of propofol (TCI level = 1.2~1.5 μg/ml)

Please provide a brief overview of the paper and its main findings.

Major and minor points

This should be the main substance of your review and should bring up any weaknesses, inconsistencies, things that need to be clarified or questions you have for the authors.

Conflicts of interest

Do you have any conflicts of interest here?

I don't have any COI this manuscript.