Materials and methods
cryptorchidism
CARDIOPULMONARY DISEASE, RESPIRATORY INFECTION, DISEASE, NEUROMUSCULAR DISEASE, PULMONARY ATELECTASIS, DIRECT INGUINAL HERNIA
This study was performed at the Children’s Hospital of Nanjing Medical University from April to August 2022 and was approved by the Ethics Committee of the Children’s Hospital of Nanjing Medical University (approval number: 202112124–1). Inclusion criteria: 1) Children aged 3 ~ 7 years, ASA class I or II, undergoing day surgery, with cryptorchidism and indirect inguinal hernia as the disease type, and open surgery as the surgical method, 2) Operation time < 2 h. Exclusion criteria: 1) preoperative respiratory infection, 2) severe cardiopulmonary disease, 3) overweight (more than 20% of standard body weight), 4) neuromuscular disease, 5) abnormal preoperative chest radiograph or chest CT, inflammatory parameters, 6) the child’s guardian did not agree to participate in this trial, 7) preoperative lung ultrasound suggested the presence of pulmonary atelectasis, 8) after removal of the laryngeal mask, the patient’s SpO2 < 90%.