This study is a multi-center, randomized, controlled, double-blinded, and parallel design study. A total of 106 patients were decided to be recruited considering a 10% dropout rate. Patients are randomizes to perform or not respiratory exercises using biofeedback device(ResCalm). The randomization numbers are generated using a computer-generated randomization code and are sealed in the opaque envelope until they are handed over to anesthesiologist in charge of patient management. Record patient preoperative t anxiety, postoperative pain, and pain medication use. Patient aged 19-64 yr, ASA class 1 or 2, and are scheduled for elective laparoscopic cholecystectomy are included. Patients who were unable to perform self breathing at regular intervals were excluded.

1. Assignment of experimental groups

   Group A: Respiratory exercise using respiratory biofeedback device(ResCalm) is applied 2-3 times / day for 3 minutes until discharge from hospital and once in the recovery room before surgery.

   Group B: General surgery schedule without control exercise.

   All patients measure STAI(state trait anxiety inventory) at the operating room entrance on the day of surgery.

2. anesthesia methods Intravenous anesthesia is performed using the target injection concentration control method. As an anesthetic, propofol / remifentanil / rocuronium is used. The artificial ventilation method is a pressure-controlled ventilation method, which maintains an appropriate pressure and performs anesthesia.

3. postoperative care After anesthesia, the patient wakes up and transfers to the recovery room to encourage self-breathing exercise. After entering the recovery room, the patient's vital signs (average blood pressure, heart rate, oxygen saturation) and analgesic use are checked immediately before leaving.

The investigators check for the presence of pulmonary complications, visual analog scale (VAS), analgesic use, and hospital patient satisfaction for 24 hours after surgery.

Inclusion Criteria:

• Adult patients aged between 19 and 64 years of age with ASA class I, II who underwent regular laparoscopic cholecystectomy under general anesthesia.

Exclusion Criteria:

• Seniors 65 years of age or older or minors under 19 years of age
• ASA (American Society of Anesthesiologists) class ≥ III
• Difficulties in proper cooperation with diseases such as Alzheimer dementia, cognitive disorders, and psychopathy
• Patients with respiratory diseases such as Asthma, Pnuemonia
• Patients with incomplete airway due to pulmonary resection, airway surgery, mouth or nose surgery