4.1. Limitations
postoperative shoulder pain, shoulder pain, pain
There were several limitations in this study. First, the follow-up period was 36 hours. This time frame was chosen because most patients undergoing laparoscopic gynecologic surgery at this institute were discharged on the morning of the second day after surgery. However, 7 patients first complained of shoulder pain at postoperative 36 hours. A longer follow-up period may be required for understanding the characteristics of shoulder pain. Second, owing to the nature of ABs, double blinding was impossible. The patients knew if they would or would not be wearing an AB while signing the consent form. This could influence the investigation of pain. Third, it was difficult to guarantee that the patient would continue to wear an AB, although the patient was asked to wear it continuously. The AB could be removed for some time such as to check dressings or the drainage bag. Third, 12L/min is a relatively high insufflation flow which was reported to associate with postoperative shoulder pain.