Hyaline membrane disease is synonymous with the so-called respiratory distress syndrome (RDSD). This clinical diagnosis is made for premature newborns with respiratory failure and those who have respiratory difficulties and tachypnea, including.
In babies, while inhaling room air, chest retraction and the development of cyanosis are recorded, which persists and progresses during the first forty-eight to ninety-six hours of life. In the case of a chest x-ray, a characteristic external picture (reticular network along with a peripheral air bronchogram) takes place. The clinical course of the disease of hyaline membranes directly depends on the weight of the child, and in addition, on the severity of the disease, the implementation of substitution treatment, the presence of concomitant infections, the degree of blood bypass through the arterial open duct and the implementation of mechanical ventilation.
Causes of pathology
Hyaline membrane diseaseobserved mainly in children born to mothers who suffer from diabetes, heart and vascular diseases, uterine bleeding. Contribute to the development of the disease is capable of intrauterine hypoxia in combination with asphyxia and hypercapnia. Due to all these causes of hyaline membrane disease, it is likely that the pulmonary circulation system is disturbed, against which the alveolar septa become impregnated with serous fluid.
Microglobulin deficiency along with the development of disseminated as well as local blood coagulation has a certain role in the occurrence of the disease under consideration. All pregnant women between the twenty-second and thirty-fourth weeks of gestation in the event of preterm labor are considered as patients who require antenatal prophylaxis with glucocorticoids without fail. This contributes to the maturation of lung surfactant in the fetus preparing for birth.
Symptoms
Clinical manifestations with existing signs of prematurity include frequent grunting labored breathing, which appears immediately or within a couple of hours after birth, with swelling of the nasal wings and retraction of the sternum. In the event that atelectasis and respiratory failure progress, and the symptoms worsen, then cyanosis occurs in combination with lethargy, respiratory failure and apnea. The skin is cyanotic.
Newborns weighing less than 1000 grams may have lungs so rigid that they simply cannot support breathingbaby in the delivery room. As part of the examination, the noise during inspiration is weakened. The peripheral pulse is minimal, edema occurs, and at the same time diuresis also decreases.
Diagnosis
In the process of studying the condition of a newborn with signs of prematurity, a clinical assessment is made, the gas composition of arterial blood is studied (we are talking about hypoxemia and hypercapnia). In addition, doctors perform a chest x-ray. Diagnosis is based on clinical symptoms, including risk factors. Chest x-ray reveals diffuse atelectasis.
Differential diagnosis is aimed at ruling out sepsis and pneumonia due to streptococcal infection, transient tachypnea, pulmonary persistent hypertension, aspiration, and pulmonary edema due to congenital malformations. Newborns usually need a blood culture and possibly a tracheal aspirate. It is extremely difficult to clinically differentiate streptococcal pneumonia from hyaline membrane disease. Thus, as practice shows, antibiotics are prescribed even before the culture result is obtained.
Features of the survey
Hyaline membrane disease in newborns can be suspected prenatally by performing fetal lung maturity tests. The analysis is carried out using amniotic fluid obtained by amniocentesis or collected from the vagina (in case of rupture of the amniotic membrane). This helps determineoptimal delivery date. This technique is appropriate for elective labor up to the thirty-ninth week, when the fetal heart rate along with the level of human chorionic gonadotropin and ultrasound cannot establish gestational age. Amniotic fluid testing may include:
- Determination of the ratio of lecithin and sphingomyelin.
- Analysis of the foam formation stability index.
- Ratio of surfactant to albumin.
The risk of hyaline membrane disease in newborns is significantly lower if the value of lecithin and sphingomyelin is less than 2, with a foam stability index of 47. Surfactant and albumin should be greater than 55 milligrams per gram.
Treatment
If a premature baby's lungs have not opened, therapy includes the following methods:
- Using a surfactant.
- Supplemental oxygen as needed.
- Perform mechanical ventilation.
Prognosis with treatment is good, mortality in this case is less than ten percent. With proper respiratory support, surfactant formation occurs over time, once its formation has begun, hyaline membrane disease in the newborn resolves within only four or five days. But severe hypoxia can lead to multiple organ failure and even death.
Special therapy for hyaline membrane disease includes intratracheal surfactanttreatment. It requires tracheal intubation, which may be necessary to achieve proper ventilation and oxygenation. Premature infants weighing less than a kilogram and infants with an oxygen requirement below forty percent may respond well to additional O2, as well as continuous nasal airway pressure treatment. The strategy of early surfactant treatment predetermines a significant reduction in the duration of artificial ventilation and a decrease in the manifestation of bronchopulmonary dysplasia.
Surfactant accelerates recovery and reduces the risk of pneumothorax, intraventricular hemorrhage, interstitial emphysema, pulmonary dysplasia and death within one year. But unfortunately, newborns who receive similar treatment for this condition have an increased risk of apnea of prematurity.
Drugs to open lungs in premature babies
Additional surfactant replacements include Beractant, along with Poractant Alfa, Calfactant and Lucinactant.
Drug "Beractant" is a lipid extract of bovine lung, which is supplemented with proteins "C", "B", as well as colfosceryl palmitate, tripalmitin and palmitic acid. The dosage is 100 milligrams per kilo of body weight every six hours as needed for up to four doses.
"Poractant" is a modified extract obtained from chopped pork lung. The drug contains phospholipids in combination with neutral lipids, fatty acids andsurfactant-associated proteins B and C. Dosage is as follows: 200 milligrams per kilo, followed by two doses of 100 milligrams per kilogram of body weight every twelve hours as needed.
"Calfactant" serves as a calf lung extract containing phospholipids along with neutral lipids, fatty acids, and surfactant-related proteins B and C. The dose is 105 milligrams per kilogram of body weight every twelve hours for up to three doses as needed.
"Lucinactant" is a synthetic substance that includes synapultide peptide, phospholipids and fatty acids. Dosing is 175 milligrams per kilogram of body weight every six hours for up to four doses.
It is worth noting that general lung compliance in a newborn may improve rapidly after this treatment. Inspiratory ventilator pressure may need to be reduced rapidly to reduce the risk of air leakage.
Prevention
To prevent such a deviation as hyaline membrane disease, special drugs are prescribed to pregnant women. When the fetus is due between the twenty-fifth and thirty-fourth weeks, the mother needs two doses of Betamethasone, 12 milligrams each, administered intramuscularly exactly one day apart.
Or apply "Dexamethasone" 6 milligrams intramuscularly every twelve hours for at least two days before delivery. This reduces the risk of developing the disease in question.or decrease in severity. This prophylaxis minimizes the risk of neonatal death from respiratory arrest in newborns, along with some forms of lung disease (eg pneumothorax).
Features of pathology
This pathology is caused by a lack of pulmonary surfactant, which, as a rule, is observed exclusively in newborns who were born before the thirty-seventh week of pregnancy. Deficiency usually worsens as prematurity increases.
Due to a deficiency of surfactant, the alveoli can close, which causes diffuse atelectasis in the lungs, which causes inflammation and swelling of this organ. In addition to provoked respiratory failure, there is an increased risk of hemorrhage, bronchopulmonary dysplasia, tension pneumothorax, sepsis, and in addition, death.
In the event that a woman in labor is expected to have a premature resolution of the burden, then it is necessary to assess the maturity of the lungs by analyzing the amniotic fluid for the ratio of sphingomyelin, lecithin, and surfactant and albumin. In case of pathology, intratracheal surfactants and provision of respiratory support as needed are required.
An expectant mother needs several doses of corticosteroids (we are talking about Betamethasone and Dexamethasone) if she is due to give birth between the twenty-fourth and thirty-fourth weeks. Corticosteroids cause surfactant productionin a fetus with a certain degree of prematurity and the risk of hyaline membrane disease is reduced.
Consequences
As complications, the patient may subsequently experience persistent ductus arteriosus, interstitial emphysema, rarely pulmonary hemorrhage and pneumonia. The appearance of chronic bronchopulmonary dysplasia, lobar emphysema, recurrent infections of the respiratory tract and cicatricial stenosis of the larynx as a result of intubation is not excluded.
What increases the risk
The risk of developing the disease in question increases with the degree of prematurity. In accordance with this criterion, the lungs of an infant may be partially or completely immature and therefore unable to provide adequate respiratory functions due to the absence or insufficient volume of surfactant produced. In such situations, newborns are shown to perform therapy that replaces this substance.
"Dexamethasone" - what is this drug?
Many are wondering why Dexamethasone is prescribed in injections. Presented drug is currently widely in demand in medicine and is a synthetic glucocorticosteroid, which has strong anti-inflammatory and immunosuppressive properties. In addition, it is able to effectively penetrate the nervous system. Thanks to these capabilities, this medication can be used in the treatment of patients suffering from cerebral edema and any inflammatory pathologies of the eyes. Here forwhat is prescribed injections "Dexamethasone".
Medication in the form of tablets and solution for injection is included in the list of essential medicines. It is able to stabilize cell membranes. Increases their resistance to the action of various damaging factors. In this regard, it is used to open the lungs of babies with the threat of developing hyaline membrane disease.
Typically, unless otherwise directed by a physician, the drug is given at 6 milligrams intramuscularly every twelve hours for two days. Given that in our country Dexamethasone is distributed mainly in ampoules of 4 milligrams, doctors recommend its intramuscular injection at this dosage three times over two days.
Chest retraction on inspiration
Against the background of the pathology of hyaline membranes, the anterior part of the chest wall retracts, which causes a symmetrical or asymmetric funnel-shaped deformity. Against the background of a deep breath, the depth of the funnel becomes larger due to paradoxical breathing, which is due to the underdevelopment of the sternal portion of the diaphragm.
The early signs of the disease under consideration, as a rule, include the presence of shortness of breath in premature babies with a respiratory rate of more than sixty times per minute, which is observed in the first minutes of life. Against the background of the progression of the pathology, symptoms also increase, for example, cyanosis increases, diffuse crepitus can occur, apnea is present along with foamy and bloody discharge from the mouth. As part of assessing the severity of a respiratory disorder, physicians use a scaleDowns.
Respiratory arrest in this pathology
The severe nature of the disease of hyaline membranes can lead to respiratory arrest. In this case, an artificial lung ventilation (ALV) drug is prescribed. This measure is used for the following indicators:
- Arterial blood acidity is less than 7.2.
- PaCO2 equals 60 millimeters of mercury and above.
- PaO2 is 50 millimeters of mercury and below when the oxygen concentration in the inhaled air is from seventy to one hundred percent.
Thus, the considered disease in newborns is due to a deficiency in the lungs of the so-called surfactant. This is most common among babies born before the thirty-seventh week. However, the risk increases significantly with the degree of prematurity. Symptoms primarily include difficulty breathing along with accessory muscle involvement and alar flaring that occurs shortly after birth. Prenatal risk can be assessed by performing a fetal lung maturation test. The fight against pathology lies in surfactant therapy and supportive care.
