neonatal air leak
Introduction
Introduction to neonatal lung leaks Neonatal lung leaks cause gas in the alveoli to leak into the chest for various reasons. The type of air leakage depends on where the gas leaks from the normal lungs, including interstitial emphysema, mediastinal emphysema, pneumothorax, and subcutaneous emphysema. Clinically significant lung leaks often occur when there are substantial lung lesions. Mainly due to poor lung compliance, high pressure expansion of alveoli such as children with respiratory distress syndrome using ventilator, or increased airway resistance such as meconium in meconium aspiration syndrome. basic knowledge The proportion of sickness: 0.01% Susceptible people: infants and young children Mode of infection: non-infectious Complications: neonatal respiratory distress syndrome shock pulmonary hypertension air embolism
Cause
Causes of neonatal lung leak
Secondary factors (65%):
A few are spontaneous pneumothorax, no cause can be found; most of the air leaks have primary lung disease, such as meconium inhalation, hyaline membrane disease, bullous bullae, localized emphysema, pneumonia and congenital lung dysplasia, Congenital pulmonary cysts and so on.
Primary factor (35%):
Frequent air pressure due to rupture of alveolar hyperinflation, and positive pressure during artificial ventilation is also a common cause.
Pathogenesis
Fetal lungs are airless, due to the viscosity of alveolar fluid, high surface tension, and immature lung elastic tissue development, so the neonatal lungs should be dilated and maintain normal functional residual capacity, the first 1 or 2 breaths, alveolar pressure 3.9kPa (40cmH2O), transient 9.8kPa (100cmH2O), the alveolar pressure generally does not exceed 2.9kPa (30cmH2O), the internal pressure is too high can cause alveolar rupture, so the gas enters the pulmonary interstitium to become interstitial lung Swelling, gas in the vicinity of lymphatic vessels and blood vessels, divided into diffuse pulmonary type and pleural medial type, sometimes emphysema enlargement is a cystic pseudocysts, interstitial emphysema can directly break into the pleura into a pneumothorax, The gas of emphysema forms mediastinal emphysema along the vascular, lymphatic or bronchial mediastinum. The newborn has a larger thymus and a smaller mediastinum. The gas that enters the mediastinum mainly accumulates in the anterior pulmonary vessels and the heart, such as the gas When the blood vessel enters the subcutaneous tissue, it becomes subcutaneous emphysema. If it enters the pericardium, it becomes a pericardial effusion. For example, it enters the pericardium along the esophagus and vascular space and enters the abdominal cavity to form a pneumoperitoneum. Then it enters the scrotum and becomes scrotal emphysema. Interstitial emphysema with Gastritis gas can occasionally enter the pulmonary veins and lymphatic vessels to form systemic intravascular air embolism, as shown in Figure 1, due to lung tissue compression, shortness of breath, blood volume reduction, abnormal ventilation and perfusion leading to intrapulmonary shunt, hypoxia, Lung compliance decreased, secondary ventilation dysfunction, cardiac compression, decreased cardiac output, increased pulmonary vascular resistance and central venous pressure caused by bradycardia and hypotension.
Interstitial emphysema pathological examination of lung enlargement, pale, pleural surface tension, according to the depression, emphysema, in the mediastinum, pericardium, chest and abdominal cavity to see free gas, lung tissue microscopic examination Alveolar dilation, part of the alveolar rupture, a large amount of air in the blood vessels and bronchi and in the connective tissue of the lobular lobes.
Prevention
Neonatal lung leakage prevention
1. Care should be taken to avoid premature birth and overdue production.
2. Prevent suffocation in the uterus and during birth.
3. Inhalation of the respiratory tract, such as meconium, should be aspirated in time.
4. Mechanical ventilation should be closely monitored, the peak pressure of inhalation should not be too high, and the suspected cases should be observed for dynamic changes and timely treatment.
5. Applying a muscle relaxant (Pancuronium) and applying a pulmonary surfactant can reduce the occurrence of air leaks.
Complication
Neonatal lung leak complications Complications neonatal respiratory distress syndrome shock pulmonary hypertension air embolism
Can be complicated by respiratory distress, shock, can be complicated by persistent pulmonary hypertension, intracranial hemorrhage, hypercapnia, to bronchopulmonary dysplasia, pericardial tamponade, air embolism.
Symptom
Neonatal pulmonary air leak symptoms Common symptoms Subcutaneous emphysema dyspnea Carbon dioxide retention Pericardial tamponade blood pressure drop
The clinical manifestations can vary with the amount of air leaks, the speed of the speed and the gas area.
1. Patients with pneumothorax may have no clinical symptoms, and the signs are often not obvious. Most of them are found in X-ray examination. Heavier cases can only show rapid increase in breathing. In severe cases, sick children are irritated, breathing is difficult, bruising, typical signs are affected side. The thoracic cage is more bulging than the healthy side, the intercostal space is full, the percussion is empty, and the auscultation breath sound disappears or decreases. When the pressure in the pleural cavity is higher than atmospheric pressure, it is called high pressure pneumothorax, which can cause the mediastinum to shift to the healthy side. When the vena cava is compressed, it can cause the surrounding vein to expand, the liver is large, the stroke volume is reduced, the pulse pressure is reduced, the pulse is weakened, and the blood pressure is lowered.
2. Mediastinal emphysema is less common than pneumothorax, generally asymptomatic, and can cause respiratory distress and pericardial tamponade when there is more mediastinal gas. Especially when there is pericardial gas, subcutaneous emphysema occurs in the neck or upper chest. ", suggesting the presence of mediastinal emphysema.
3. Pneumoperitoneum can enter the abdominal cavity through the mediastinum, causing pneumoperitoneum, which is manifested as abdominal flatulence, percussion drum sound, need to be identified with perforation of the digestive tract, but the latter abdominal wall often has edema, finger pressure, and signs of peritoneal stimulation, Distinguish from this disease.
4. Interstitial emphysema gas can extend along the bronchial and perivascular loose interstitial to the hilar. In severe cases, it can compress small airways and reduce lung compliance, resulting in difficulty breathing, wheezing, hypoxia and CO2 retention.
Examine
Neonatal lung leak check
In the change of blood gas value, hypercapnia is an early change, and the postoperative arterial oxygen partial pressure will gradually decrease. When there is infection, peripheral blood leukocytes and neutrophils are significantly increased, and there may be a left shift of the nucleus and toxic particles appear. .
Regular chest X-ray film, electrocardiogram, B-ultrasound and other examinations.
1. X-ray examination is mainly based on X-ray examination. When the pneumothorax is seen, the external thoracic gas is too light, no lung texture, and the inside of the compressed lung forms a clear edge. When the pneumothorax is high, the mediastinum can be seen. The lateral displacement, the ipsilateral diaphragm is low, and the mediastinal emphysema shows a transparent gas shadow on the periphery of the heart. The lateral position is between the heart and the sternum, and the thymus can be raised by the upper mediastinum. It can be a sail-like shadow. When the pericardium accumulates, the heart is contracted, and the pericardial cavity is visible. The outside of the heart is covered with a layer of shadow. When the pneumoperitoneum is seen, the underarm is formed. It needs to be identified according to the clinical and digestive tract perforation. Emphysema can be seen in the narrow strip of light transmission from the hilar to the trachea, the blood vessel is distributed.
2. Transillumination can not be moved by critically ill children, and can be transparently illuminated by cold light source to determine the air leakage site, which is convenient for puncture and decompression.
3. Ultrasound examination Ultrasound can assist in the diagnosis of atypical mediastinal emphysema, and can be used to identify medial pneumothorax and mediastinal emphysema.
4. Endoscopic examination of cervical mediastinal emphysema can be used for urgency endoscopy to assist diagnosis and treatment.
Diagnosis
Diagnosis and diagnosis of neonatal lung leak
diagnosis
According to the medical history, clinical symptoms and signs plus X-ray examination can be diagnosed.
Differential diagnosis
Gastric abdomen can be seen under the axillary gas, need to be differentiated according to clinical manifestations and gastrointestinal perforation, pay attention to the identification of respiratory distress syndrome.
