I. What is pneumoperitoneum? What is the role? Artificial pneumoperitoneum: also known as pneumoperitoneum, is a medical term, is a medical method, pneumoperitoneum is the key to successful laparoscopic surgery, before the operation must first establish an artificial pneumoperitoneum, so that the peritoneal wall and organs are separated, the expansion of the abdominal cavity to facilitate the operation, and to avoid damage to the organs when the set of needle puncture into the abdominal cavity. During laparoscopic surgery, the pneumoperitoneum can expand the operative field, fully expose the abdominal organs, and provide the operator with a clear view and a suitable operating space so that the operation can be performed normally. Second, will there be complications? When do they occur? What are the most common ones? Pneumoperitoneal complications are mostly a series of clinical symptoms that occur during the establishment and maintenance of the pneumoperitoneum or after the end of the pneumoperitoneum. 1. The pneumoperitoneum is prone to subcutaneous emphysema, visceral injury and vascular injury and bleeding during the establishment of the pneumoperitoneum. 2, pneumoperitoneum maintenance process and prone to hypercapnia and acidosis and other complications. 3, nausea and vomiting, shoulder pain and venous thrombosis of the lower extremities that occur after surgery are called delayed pneumoperitoneum complications. Complication 1: hypercapnia Causes: CO2 gas diffusion absorption through the peritoneum, pulmonary ventilation/blood flow disorders leading to CO2 storage and reabsorption hypercapnia. Hazards: Hypercapnia and acidosis can cause increased sympathetic excitability and release of catecholamines, resulting in increased heart rate and increased myocardial autoregulation. With the increase in the rate and duration of C O 2 accumulation, the vagal excitability and potassium increase, which can produce myocardial depression, atrioventricular block, and ectopic rhythm. Correction: Intraoperative close observation and monitoring. Intraoperative P C O 2 excess and p H decrease that cannot be corrected should be considered as an intermediate open procedure. During surgery, attention should be paid to adjust the ventilation volume to facilitate C O 2 expulsion, and the application of low-pressure pneumoperitoneum should also be considered. Complication 2: shoulder pain Causes: The anatomical basis of shoulder pain is that the nerves innervating the septal muscle and the skin nerves of the shoulder are located in the same place as C 3. According to Aitolla et al, the stimulation of the septal muscle by carbonic acid produced by the pneumoperitoneum is the cause of postoperative shoulder pain. Corrective measures: slow down the inflation rate and keep the pneumoperitoneum pressure at a low level when creating the pneumoperitoneum, and try to empty the C O 2 in the abdominal cavity after surgery; this can reduce the production of carbonic acid and reduce the pulling effect on the septal muscle; thus reducing the occurrence of postoperative shoulder pain. Complication 3: nausea and vomiting Corrective measures: prophylactic use of anti-vomiting drugs to reduce the incidence of postoperative nausea and vomiting, in the event that the duration of the pneumoperitoneum cannot be shortened and the surgical field is not affected, lower the intraoperative CO2 pneumoperitoneum pressure as much as possible after the operation to empty the abdominal CO2.