Nowadays, fentanyl is a kind of opioid analgesic that is commonly used. The opioid analgesics are not only fentanyl, but also the newer ones such as sufentanil, alfentanil and remifentanil. These new drugs, compared to traditional fentanyl, have stronger analgesic strength, shorter duration of action, and faster elimination in the body. Therefore, the duration of respiratory depression is much shorter and safer. The side effects of fentanyl tend to produce abdominal wall stiffness and cause respiratory impairment. After using fentanyl, it is easy to produce shallow breathing, reduced breathing and even apnea, which mainly affects the respiratory system more.