What Is Neonatal Pneumonia?

Neonatal pneumonia can be divided according to different causes: neonatal aspiration pneumonia and neonatal infectious pneumonia. The former can be divided into amniotic fluid aspiration pneumonia, meconium aspiration pneumonia, and milk aspiration pneumonia.

Basic Information

English name

neonatal pneumonia

Visiting department

Pediatrics, respiratory

Multiple groups

Newborn

Common locations

lung

Common causes

Associated with inhalation of amniotic fluid, meconium or milk, or with infection

Common symptoms

Dyspnea, cyanosis

Contagious

no

Causes of neonatal pneumonia

Neonatal aspiration pneumonia

Chemically induced lung inflammation / secondary infection in neonates due to inhalation of amniotic fluid, meconium, or milk is collectively referred to as neonatal aspiration pneumonia.

(1) Amniotic fluid inhaled pneumonia causes fetal distress caused by obvious intrauterine hypoxia. When breathing occurs, breathing difficulties are caused by exfoliated epithelial cells in the amniotic fluid that obstruct the end airway, followed by changes in pulmonary chemical inflammation or subsequent Infected.

(2) Meconium aspiration pneumonia The birth rate of meconium in amniotic fluid was more than 30% in those who delivered at> 42 weeks of gestational age, and very few meconium was discharged into amniotic fluid at <34 weeks. Meconium pollution of amniotic fluid has been used as a synonym for intrauterine distress, but it is not very related to Apgar score, fetal heart abnormality, umbilical cord blood pH and so on. Sign. Normal fetal intrauterine respiratory activity will not cause meconium aspiration, but fetal distress caused by obvious intrauterine hypoxia, can cause meconium to enter small airways or alveoli when panting occurs. Clinically, severe amniotic fluid, meconium contamination, too fast fetal heart rate, and low umbilical artery pH values suggest that the possibility of meconium aspiration requires active intervention. If meconium has been inhaled in the palace or is contaminated with amniotic fluid, the meconium in the airway is not removed in time after birth, and the meconium can enter the distal airway with the establishment of breathing. Meconium first causes mechanical obstruction of small airways. When there is complete obstruction, atelectasis can occur; when meconium partially obstructs the airway, a valve-like effect can be produced, the gas is easily inhaled but not easy to exhale, and emphysema occurs, which can further develop into mediastinal emphysema or pneumothorax . Due to the stimulation of small airways by inhaled meconium, it can cause chemical inflammation and pulmonary interstitial edema; emphysema persists during chemical inflammation and lung collapse is more obvious. The components that cause inactivation of surface-active substances in meconium include lysoprotein, free fatty acids, bile salts, fetal hair and other substances, which can inactivate lung surface-active substances. On the basis of asphyxia and hypoxia, atelectasis, lung collapse, chemical inflammation injury, and secondary inactivation of pulmonary surfactant caused by meconium inhalation can further aggravate lung collapse, hypoventilation and low oxygen. As a result, the pulmonary blood vessels can not adapt to the postnatal environment and decline, and there is a continuous increase, that is, persistent pulmonary hypertension in the newborn. About one-third of children can develop this disease.

(3) Premature infants with milk aspiration pneumonia or those with bronchopulmonary dysplasia are most likely to experience reflux in the stomach; in swallowing disorders, esophageal atresia or tracheoesophageal fistula, severe cleft palate, or excessive feeding of rabbit lips, etc. Breast inhalation is also prone to occur. Due to local stimulation before inhalation, protective closure of epiglottis was caused, and the child presented with apnea. The clinical manifestations were symptoms of respiratory obstruction; respiratory distress and corresponding X-ray lung infiltrates appeared after inhalation. The clinical manifestations and infectious pneumonia were often difficult Identification. Pulmonary edema, hemorrhage, etc. reduce lung compliance, and secondary bacterial infections can occur in milk aspiration pneumonia. Tracheal aspirate can be seen in milk or lipid-containing macrophages.

2. neonatal infectious pneumonia

Prenatal and intrapartum infections are transmitted sexually by amniotic fluid or blood. The pathogenic microorganisms are similar to pneumonia caused by intrauterine inhalation of contaminated amniotic fluid. Gram-negative bacilli are more common in bacterial infections. In addition, there are group B streptococci, chlamydia trachomatis, and urease. Ureaplasma and viruses such as CMV (cytomegalovirus). Postpartum infections are easily transmitted to newborns when they are in direct contact with infants with respiratory infections; in umbilitis, skin infections and sepsis, pathogens are transmitted to the lungs by blood and cause pneumonia; medical incubators, aspirators, nebulizers, trachea Disinfection of tubes, etc. is not strict, the medical staff's concept of asepticity is not strong, and their hands are not washed frequently. Blood products containing CMV, HIV and other viruses can cause diseases. High-risk factors for iatrogenic infections: Birth weight <1500g; Long-term hospitalization; Overcrowded ward and inadequate disinfection system; Too few nurses; Poor conception of sterility of medical staff; Abuse of antibiotics; Use of ventilator cross Infection; multiple invasive procedures, tracheal intubation for more than 72 hours or multiple intubations. The most common pathogenic bacteria are Staphylococcus aureus and Escherichia coli. Many opportunistic pathogens such as Klebsiella, Pseudomonas aeruginosa, Citrobacter, Staphylococcus epidermidis, and Acinetobacter can also cause disease in newborns. In recent years, the positive rate of Staphylococcus epidermidis in neonates with pneumonia and sepsis has been increasing. In addition, anaerobic bacteria, chlamydia trachomatis, and deep fungal infections are on the rise and should be paid attention to. The virus is more common in respiratory syncytial virus and adenovirus infections and is found in advanced neonates. Prone to epidemics and secondary bacterial infections. CMV infection can also occur after birth, and the disease is milder than intrauterine infection. Others: Pneumocystis carinii, Ureaplasma urealyticum, Chlamydia can cause pneumonia.

Clinical manifestations of neonatal pneumonia

Neonatal aspiration pneumonia

(1) Amniotic fluid aspiration pneumonia After resuscitation, dyspnea and bruising occur, and fluid or foam can flow from the mouth. There is a wet murmur on auscultation of the lungs. General symptoms and signs last more than 72 hours.

(2) The severity of meconium aspiration pneumonia is related to the nature (thin or thick) and quantity of amniotic fluid inhaled. Clinically, it can range from mild dyspnea to severe respiratory distress. After resuscitation, the newborn will have shallow breathing (> 60 beats / min), nasal inflammation, three concave signs, moaning, and cyanosis. In severe cases, respiratory failure may occur. The thoracic bulge was barrel-shaped, with thick wet murmurs in the early lungs, and fine wet murmurs later. The above symptoms and signs are more obvious 12 to 24 hours after birth. When pneumothorax or mediastinal emphysema is complicated, breathing difficulty suddenly increases, and respiratory sounds are significantly reduced; when persistent pulmonary hypertension is present, it shows persistent severe cyanosis, which does not respond to general oxygen therapy; when cardiac insufficiency occurs, the heart rate increases and the liver enlarges. Clinical dyspnea often lasts from days to weeks after birth.

(3) Milk aspiration pneumonia Suddenly there is respiratory arrest, bruising, or coughing after breastfeeding, and there is milk aspiration in the airways; clinically, respiratory distress, tri-concavity signs, increased lung wetness, and symptoms and signs lasting longer than 72 Hours; there are primary symptoms of inhalation. Pay attention to the clinical manifestations of complications, such as secondary infection and cardiac insufficiency.

2. neonatal infectious pneumonia

During pneumonia, due to the reduction of the area of gas exchange and the role of pathogens, hypoxia and infection poisoning symptoms such as hypothermia, poor response, coma, convulsions, and respiratory and circulatory failure can occur. Can be caused by toxins, inflammatory cytokines, hypoxia and metabolic disorders, immune dysfunction. The occurrence of hypoxia can be caused by the following factors: the small airway thickens due to inflammation and edema, and the lumen becomes smaller or even blocked. If the small bronchus is completely blocked, it can cause atelectasis. Pathogens invade the alveoli after they invade the alveoli, promote the production of inflammatory mediators and anti-inflammatory factors, aggravate tissue destruction, increase profibrogenic factors, and cause pulmonary fibrosis. Inflammation reduces the production of PS (phosphatidylserine) and increases inactivation, which can cause micro atelectasis and decrease alveolar ventilation. The formation of hyaline membranes, inflammation of the alveolar wall, cell infiltration, and edema cause thickening of the alveolar membrane and cause ventilation insufficiency. When cells are hypoxic, the tissues' uptake and utilization of oxygen are inadequate, coupled with high neonatal fetal hemoglobin and low 2,3-DPG (2,3-bisphosphoglycerate), which can easily cause tissue hypoxia and acid-base balance Imbalance, damage to the enzyme system in the cytoplasm, failure to maintain normal function, can cause multiple organ inflammatory reactions and dysfunction, leading to multiple organ failure.

Newborn pneumonia examination

Neonatal aspiration pneumonia

(1) X-ray examination of amniotic fluid aspiration pneumonia may be a patchy shadow with a lighter density and may be accompanied by mild or moderate emphysema.

(2) Meconium aspiration pneumonia X- ray examination X-ray changes are more obvious 12 to 24 hours after birth. Typical manifestations are scattered coarse particles or flakes, cloud-like shadows with increased density, or segmental atelectasis and emphysema, which may be accompanied by pneumothorax and / or mediastinal gas; combined with PPHN (newborn persistence Pulmonary arterial hypertension) decreased bronchial shadow and increased pulmonary permeability; characteristic X-ray changes of hyaline membrane disease were seen when ARDS (adult respiratory distress syndrome) was combined. The chest radiograph and the severity of clinical manifestations are not proportional. Blood gas analysis Arterial blood gas showed hypoxemia, hypercapnia, and metabolic or mixed acidosis. If hypoxemia is obvious, pay attention to the presence of persistent pulmonary hypertension when it is not proportional to the degree of lung disease or difficulty breathing.

(3) X-ray examination of milk aspiration pneumonia may widen hilar shadows, thicken lung texture or appear patch shadows, which may be accompanied by emphysema or atelectasis. Interstitial pneumonia and even fibrosis can occur in repeated inhalers.

Diagnosis of neonatal pneumonia

Neonatal aspiration pneumonia

(1) Amniotic fluid aspiration pneumonia History: history of fetal distress or postnatal asphyxia; clinical manifestations; X-ray examination.

(2) Meconium aspiration pneumonia Medical history: often have a clear history of hypoxia, such as intrauterine distress (fetal movement and / or abnormal fetal heart), history of asphyxia or chronic intrauterine hypoxia; amniotic fluid meconium pollution Evidence, such as meconium in the amniotic fluid, placenta and children's fingernails, skin, umbilical cord staining, and meconium in the mouth and nasal aspirates; meconium can be seen in the glottis or in the trachea during tracheal intubation. clinical manifestations. Related inspections.

(3) Milk aspiration pneumonia History: There are often incentives. Premature babies are more common, especially those with bronchopulmonary dysplasia with swallowing coordination dysfunction, gastroesophageal reflux; esophageal atresia or tracheoesophageal fistula; severe cleft lip and palate. clinical manifestations. X-ray performance.

2. neonatal infectious pneumonia

Medical history: pay attention to asking about high-risk factors. Such as intrauterine-pregnant women's history of infection during pregnancy (mainly early virus, late bacteria), amniocentesis, chorioamnionitis, and premature rupture of membranes, etc .; during delivery-fetal distress, prolonged labor, odorous amniotic fluid Taste or placental dregs, etc .; postnatal-respiratory infection patients with contact history, umbilitis, skin infections and high risk factors for nosocomial infections such as birth weight <1500g, long-term hospitalization, mechanical ventilation for more than 72 hours, invasive procedures, long-term intravenous nutrition, etc. . Clinical manifestations: Intrauterine infection occurs more than 3 days after birth. Symptoms occur during or after birth 3 days after birth. Clinical severity varies. Breath only increases in mild cases, and dyspnea is severe in severe cases, accompanied by moaning, spitting, irregular breathing rhythm, or apnea. May be accompanied by fever or hypothermia, poor response, poor feeding and other symptoms of infection and poisoning. The lungs can reach wet rales. Severe complications often include heart failure, DIC, shock, persistent pulmonary hypertension, and pulmonary hemorrhage. X-ray examination is an important diagnostic basis. X-ray characteristics vary with different pathogens. When the virus is infected, only the texture of the two lungs is thick or scattered in patchy shadows. When the bacteria are infected, there is a patchy density increase in the lungs, which can be associated with bullae and pneumothorax. The changes of chest radiograph of pneumonitis infected with hemolytic streptococcus in early-onset group B and RDS are not easy to distinguish. blood test: bacterial infection increases neutrophils, nuclear shift to the left, platelets can be reduced. Cord blood IgM can be increased. CRP (C-reactive protein) is increased during bacterial infection. Etiology test: smear and culture of tracheal secretions, and blood culture if necessary. Smears and cultures of tracheal secretions within 1 hour after birth and within 8 hours after birth can suggest pathogenic bacteria for intrauterine infection. Serum-specific IgM and PCR (Polymerase Chain Reaction) detection. blood gas analysis: determine respiratory failure and type.

Neonatal pneumonia treatment

Neonatal aspiration pneumonia

(1) Amniotic fluid aspiration pneumonia Symptomatic treatment: choose a hood to inhale oxygen or mechanical ventilation according to the degree of hypoxia; prevention and control of infection: use broad-spectrum antibiotics against Gram-negative bacteria.

(2) Meconium aspiration pneumonia The key is to improve ventilation and oxygen therapy support. Clean up the respiratory tract: For newborns who are contaminated with amniotic fluid and meconium and are distressed in the uterus, it is necessary to immediately evaluate whether they are "vigorous". "Vitality" means no breathing or wheezing breathing, low muscle tone, and / or heart rate < 100 times / minute. Intubation should be performed immediately before breathing occurs after childbirth. Note that the contents of the stomach should also be sucked clean to avoid aspiration. Those with vitality should pay attention to monitoring for signs of dyspnea and bruising. Monitoring and observation items: monitor body temperature, breathing, heart rate, blood pressure, urine volume, and oxygen saturation. Observe the symptoms and signs of respiratory distress closely to reduce unnecessary irritation. X-ray chest radiographs are used to monitor for lung lesions, noting whether they are complicated by pneumothorax or mediastinum. Oxygen therapy: When PaO ₂ <60mmHg or TcSO ₂ <90%, oxygen therapy should be performed according to the degree of hypoxia. It is advisable to maintain PaO ₂ 60 80mmHg or TcSO ₂ 92% 97%. The lighter person chooses the nasal tube and hood to give oxygen. When FiO ₂ > 0.4, CPAP (continuous positive airway pressure) treatment can be used, PEEP (positive end-expiratory pressure) pressure 4 ~ 5cmH ₂ O, clinical and X-ray films should be careful when the lung is over-inflated, the pressure should not be too high. When PaO ₂ <50mmHg, PaCO ₂ > 60mmHg, SIMV (Synchronized Intermittent Ventilation) mechanical ventilation is often used. For example, chest radiographs are mainly atelectasis or blood gas is mainly hypoxemia. Peak inspiratory pressure during initial adjustment It can be slightly higher than 25 30cmH2O, the inhalation time can be appropriately extended, the inhalation / exhalation ratio is 1: 1 1.2, and the breathing frequency is 35 40 beats / min; if the chest radiography is mainly emphysema or the blood gas is mainly increased by PaCO ₂ During the initial adjustment, the peak inspiratory pressure should be slightly lower by 20 ~ 25cmH ₂ O, the inspiratory / exhalation ratio is 1: 1.2 ~ 1.5, and the breathing frequency is 40 ~ 45 times / minute. For those who are ineffective in using regular frequency ventilators or have air leaks, such as pneumothorax and interstitial emphysema, use high-frequency oscillating ventilation. The frequency of high-frequency breathing is 8-10Hz, which may have better results. When combined with persistent pulmonary hypertension, normal frequency ventilation at a fast frequency (> 60 beats / min) can be used to maintain pH 7.45 to 7.55, PaCO ₂ 25 to 35 mmHg, PaO ₂ 80 to 100 mmHg, TcSO ₂ 97% to 99%. Alkaline blood can reduce pulmonary arterial pressure, which is a classic and effective treatment in clinical practice. In addition, NO inhalation, high-frequency oscillatory ventilation and extracorporeal membrane lung (ECMO) have also achieved certain effects. Symptomatic supportive treatment: pay attention to warmth, sedation, hot card supply, maintain normal blood pressure, blood sugar, calcium, and correct acidosis. Ensure the amount of liquid and limit the liquid appropriately. Pay attention to chest physiotherapy, turn over regularly, pat your back, and expectorate, especially for mechanically assisted breathing. Use of pulmonary surfactant: The results of a multicenter randomized controlled clinical trial in China showed that pulmonary surfactant (200mg / kg) was used to treat MAS (Meconium Aspiration Syndrome), and the blood oxygenation status was significant at 6 hours and 24 hours after application. Increase, and the early application of surface-active substances can reduce the occurrence of air leakage, improve oxygenation, and shorten the time of applying mechanical ventilation. Application of antibiotics: It is difficult to distinguish MAS and bacterial infectious pneumonia based on clinical manifestations and X-ray films alone. It is often necessary to choose broad-spectrum antibiotics for treatment, and actively look for evidence of bacterial infection (blood culture, tracheal secretion culture, etc.) to determine the course of antibiotic treatment.

(3) Milk aspiration pneumonia Clean the respiratory tract: Immediately suck it with a straw or intubation to keep the airway open. Improve ventilation and oxygen supply: choose the way of oxygen inhalation according to the degree of hypoxia. X-ray chest radiographs are used to monitor for lung lesions, noting whether they are complicated by pneumothorax or mediastinum. Prevention and control of infection: Use broad-spectrum antibiotics, and take tracheal secretions for bacterial culture and drug sensitivity tests. symptomatic treatment: ensure nutrition. Mild patients can be fed a small number of times, and severely unable to feed need intravenous fluids, and parenteral nutrition if necessary. Treat various complications in a timely manner.

2. neonatal infectious pneumonia

Respiratory tract management: nebulized inhalation, postural drainage, regularly turned over, patted the back, and sucked out the oral and nasal secretions in time. Those with severe atelectasis performed tracheal irrigation. oxygen supply: maintain blood gas PaO ₂ between 50 ~ 80mmHg. Give mild oxygen to the hood; CPAP can be used when hypoxia does not improve and blood gas is mainly hypoxemia; blood gas PaCO ₂ 70mmHg, or FiO ₂ > 0.8, PaO ₂ 50mmHg, or repeated Apnea requires mechanical ventilation. Because pneumonia is often accompanied by emphysema, the initial adjustment parameter PIP (peak inspiratory pressure) is about 20 cmH ₂ O, PEEP ₃ to 4 cm H ₂ O, and respiratory frequency 40 to 50 times is appropriate. Infection control: When bacterial infection is considered and the pathogen is unknown, the third-generation cephalosporin is preferred, and combined application is necessary when necessary. Group B hemolytic streptococcal infection or Listeria pneumonia can be used ampicillin. Chlamydia trachomatis and Ureaplasma urealyticum pneumonia are preferred for erythromycin. For cytomegalovirus pneumonia, ganciclovir is preferred. Actively treat various complications. Support the treatment to ensure the caloric and physiological requirements. It is advisable to breastfeed a small number of times to avoid inhalation. Intravenous rehydration for those who cannot eat. Be careful not to infuse too quickly to avoid heart failure. Intravenous injection of immunoglobulin can be used for 3 to 5 days to increase the body's immune function.

Neonatal pneumonia prevention

Children with milk aspiration pneumonia should pay attention to: it is not easy to increase the milk volume of premature babies too quickly; there is a risk of inhalation during feeding before suspected malformations such as esophageal atresia, so water or glucose water is often recommended for the first feeding; Lying sideways after feeding reduces the risk of aspiration. ^[1-4]