Congenital heart disease is a common congenital malformation, and its incidence ranks first in birth defects. With the continuous improvement of treatment technology and the concept of “emergency and sub-emergency surgery” in China, the age of children with congenital heart disease seeking consultation and requesting surgery is getting younger and younger, so it is crucial to strictly grasp the indications for surgery, correctly select the timing of surgery and actively and correctly handle the perioperative period. The concept of emergency surgery is very important.
I. The concept of emergency surgery
Emergency surgery for critical precocious heart disease refers to surgical treatment for infants and even newborns within 48 hours after a clear diagnosis; subemergency surgery refers to surgical treatment performed as soon as possible after a clear diagnosis with surgical indications. If surgery is not performed in time, most of the children will die due to refractory pneumonia combined with heart failure or uncorrectable hypoxemia, acidosis and pulmonary hypertension, so it is necessary to strengthen the concept of emergency or subemergency surgery for children with critical precocious heart disease, and actively prepare and perform surgery.
II. Types of critical precocious heart disease
Critical precardiac disease refers to the anatomical malformation of the great vessels of the heart causing hemodynamic abnormalities, resulting in hypoxemia, acid-base imbalance and progressive deterioration of the child, or complicated by recurrent respiratory tract infections and heart failure, making it difficult for medical treatment to be effective, and the only way to survive is to use surgical or interventional treatment for radical or palliative treatment.
Most of the precardiac diseases requiring emergency surgery or subacute surgery are complex precardiac diseases: aortic stenosis combined with ventricular septal defect, arterial catheterization, aortic arch dissection, right ventricular double outlet with pulmonary hypertension, complete atrioventricular septal defect, tetralogy of Fallot, tricuspid atresia, complete pulmonary venous ectopic drainage, complete transposition of the great arteries, pulmonary atresia, severe pulmonary stenosis, and permanent arterial stem.
Simplex type is mainly ventricular septal defect combined with pulmonary hypertension and combined arteriovenous catheterization.
The indications for emergency and subacute surgery and the timing of surgery
Not all congenital heart diseases require emergency surgery, after all, emergency surgery is very risky and has a high mortality rate, so it is important to strictly grasp the indications for surgery after weighing the pros and cons.
The indications are mainly the critical state of congenital heart disease, including.
1, recurrent refractory pulmonary infections.
2, heavy cyanosis and repeated episodes of hypoxia, leading to severe hypoxemia and the possibility of sudden death at any time.
3, the occurrence of heart failure, which is difficult to control with medications.
4, incomplete correction of malformation or large residual leak, resulting in severe cardiac insufficiency.
5, large shunt flow, pulmonary hypertension formation, there may be a bidirectional shunt.
Mastering the indications for surgery and choosing the best timing for surgery can greatly improve the success rate of surgery. Since the most common conditions requiring emergency or subemergency surgical treatment are large left-to-right shunts or precordial disease with severe pulmonary hypertension, in principle, subemergency surgery should be performed in less than three months; however, if symptoms of cardiac insufficiency or pulmonary infection have already appeared, cardiac strengthening and anti-infection treatment by internal medicine is required first, and the presence or absence of rales in the lungs It is not an indication for surgery, but the control of symptoms meets the following conditions.
(1) absence of fever for greater than 48 hours.
(2) Normal white blood cell count.
(3) Chest radiograph suggesting reduced pulmonary exudate.
(4) Blood gas analysis showing PO2 > 60 mmHg and PCO2 < 50 mmhg.
(5) Cardiac ultrasound shows predominant left-to-right shunt at the ventricular level.
(6) Blood culture and sputum culture were negative. Emergency surgical treatment was prepared immediately after the symptoms were controlled.
If the infection cannot be controlled by internal medicine, or even if acute heart failure occurs, emergency surgery is still required. Although the risk of surgery increases, it can still reduce the mortality rate of the child compared with continued conservative treatment by internal medicine. Severe heart failure and near-death children are not absolute contraindications to surgery. < span="">
IV. Perioperative management
1. Adjustment of preoperative optimal status
Successful selection of the best time for surgery is the key point for successful surgery, and most children’s optimal state for surgery is regulated by preoperative preparation. First of all, we need to establish 24-hour consultation and treatment classes, medical and nursing as one, and combined medical and emergency surgery as one, in order to diagnose and treat at the fastest speed and avoid time delay. The diagnosis of precardiac disease mainly relies on non-invasive examination, cardiac ultrasound and magnetic resonance imaging as the main means of examination, minimize the invasive examination of catheters in newborns and small infants, it is really necessary, it is best to cooperate with anesthesiology to complete the examination and surgery under anesthesia at one time. Preoperative medical treatment is mainly to improve hypoxemia, correct acidosis, control respiratory tract infection and enhance nutritional therapy. Specifically, sedation, oxygenation, dextrose transfusion to dilute blood and reduce blood viscosity, cardiac strength, diuresis, nutritional supplementation, transfusion of whole blood, albumin and powerful antibiotics to fight infection, etc. If necessary, mechanical assisted ventilation therapy is feasible.
2.Intraoperative protection of organs
The principle is to perform radical surgery in one phase as much as possible, and to perform physiological correction if the anatomy is difficult to be corrected, so as to shorten the operation time as much as possible. Intraoperative extracorporeal circulation can use membrane oxygenator, deep hypothermia low flow, deep hypothermia stop circulation combination, PH steady state management of blood gas, blood or crystal myocardial protection fluid, uniform and smooth temperature rise and fall and extracorporeal circulation modified ultrafiltration and other techniques. The deep hypothermia technique can reduce the damage to the cerebral nerve; the blood-containing myocardial protective fluid contains potassium and magnesium, which can reduce the damage to the myocardium by ischemia-reperfusion; the modified ultrafiltration technique of extracorporeal circulation can filter the inflammatory factors in the blood, reduce the inflammatory response, increase the colloid osmotic pressure and erythrocyte specific volume, and at the same time filter out the excess water from the body, thus reducing the cardiac edema.
3.Postoperative monitoring and management
Postoperative low cardiac output and pulmonary infection are the main complications, so it is important to strengthen the management of heart, lung and kidney after surgery.
(1) General nutritional support treatment. Routine postoperative warming, micro-pump infusion, rest, sedation and analgesic treatment can reduce airway pressure, cardiopulmonary work and energy consumption; early enteral nutrition is beneficial to the child’s recovery; controlling fluid intake and output, maintaining acid-base and water-electrolyte balance can reduce interstitial edema.
(2) Cardiac management. Intraoperative use of blood-containing myocardial protective fluid protects the myocardium, and postoperative use of orthomyocardial drugs and reduction of cardiac afterload can increase cardiac output and reduce low cardiac output; on the other hand, the occurrence of low cardiac output can be reduced by delaying chest closure (three days after surgery) and reducing the compression of the sternum on the postoperative edematous heart.
(3) Pulmonary management. In addition to sedation and rest to reduce oxygen consumption of the lungs, enhanced respiratory management can be achieved through the use of ventilators, inhalation of NO, and the use of appropriate medications. Ventilator use mode is generally SIMV+PC, SIMV+VC and PRVC; parameter settings are generally low tidal volume, high frequency, low PEEP and low partial pressure of carbon dioxide; prevention of ventilator-associated pneumonia can be treated by regular back patting and airway cleaning; the use of ventilator needs to be withdrawn as early as possible. Inhaled NO treatment is mainly for pulmonary hypertension, hyperventilation can be given and inhaled NO, initially 20-40ppm, gradually decrease to 5-10ppm. use appropriate drugs, such as small dose of epinephrine after performing body-pulmonary bypass, to increase pulmonary artery systolic pressure and thus improve oxygen saturation.
(4) Renal management. Postoperative low cardiac output can cause acute renal failure, so timely treatment with peritoneal dialysis can effectively improve the postoperative survival rate.
In conclusion, emergency and sub-emergency surgical treatment of critical preconditioning is safe, feasible and valuable, but it is necessary to correctly grasp the timing of surgery and strictly manage the perioperative period, and the timing of surgery and surgical methods still need to continue to accumulate clinical experience and discussion, and the indications of preoperative surgery timing also need to be further improved, and the close cooperation with anesthesiology during surgery also needs strict and perfect management of anesthesia, and the postoperative monitoring also needs to be further improved. We strive to minimize the mortality rate of emergency surgery and sub-emergency surgery.