Children with critical congenital heart disease can develop severe cyanosis, hypoxic respiratory distress and heart failure after birth, and it is difficult to improve the symptoms permanently with conservative medical treatment, and the children are soon on the verge of death, so they need emergency or subacute surgical treatment. According to statistics, the death rate of children requiring emergency or subemergency surgery in the neonatal period is 70% to 90% within 1 month if they are not treated with timely surgery. In terms of specific congenital heart malformations in the neonatal period, the natural mortality rate of children with complete transposition of the great arteries is 29% within 1 week of birth and 52% within 1 month; the mortality rate of children with hypoplastic left heart syndrome is 25% within 1 week of birth, and those who survive will soon develop pulmonary hypertension and lose the opportunity for future physiological correction; the natural mortality rate of children with intact septal pulmonary atresia is 25% within 1 week of birth and 50% within 2 weeks. The natural survival time of children with aortic arch dissection is 4-10 days on average, and 75% of them die within 1 month; the natural death rate of children with permanent arterial trunks is 50% within 1 month of birth; and children with complete pulmonary venous ectopic drainage die naturally at an average of 7 weeks. Therefore, there is an objective need for emergency surgery in children with critical congenital heart disease in the neonatal period. Severe hypoxemia due to cardiac malformations or recurrent respiratory infections due to large intracardiac shunts, cardiac insufficiency, respiratory failure, or other cardiac causes that place the child in an acute, critical, or severe condition are indications for emergency or subemergency surgery in neonates and small infants. We believe that the best time to operate on these children should be when the critical state is temporarily relieved after active medical treatment and when the acidosis, hypoxemia and electrolyte imbalance are improved, which is the so-called “optimal state”. For these critically ill congenital heart disease children, our hospital organizes multi-departmental cooperation before surgery, actively prepares, improves hypoxia, corrects acidosis, maintains electrolyte balance, and strives for the best time for surgery.