Respiratory Distress Syndrome
Definition:
Respiratory distress syndrome (RDS), also referred to as hyaline membrane disease (HMD), is a severe respiratory disorder confined primarily to prematurely born babies. It is caused by a temporary deficiency of a lung lining material called surfactant.
Causes of RDS:
Usually a developing fetus does not produce their own lung surfactant until the last few weeks of pregnancy. Surfactant is a complex material composed of lipids (fats) and protein that is secreted by cells that line the air sacs of the lung. Normally, lung surfactant forms an internal elastic lung lining that tenses during inhalation, so we don’t overstretch our lungs, and relaxes when we exhale so our lungs don’t collapse. Babies who are born deficient in surfactant have breathing problems because many air sacs collapse and others inflate unevenly.
Symptoms:
Increased breathing effort and rate (difficulty breathing from birth), cyanosis (looking bluish), retractions (using extra efforts of chest muscles to breathe), nasal flaring (nostrils enlarging with each breath taken), grunting on expiration (infant attempting to keep lungs expanded), stopping breathing from fatigue (apnea).
Chest X-Ray:
The collapse in the lungs shows up as whiteness on the x-ray instead of the normal black. Often the airways in the lungs, which do not collapse, can be seen.
Treatment:
Oxygen is given. The amount is regulated by measuring the proportion of oxygen in the blood through the skin, pulse oximetry, or by direct measurement of arterial blood gas (ABG). Continuous Positive Airway Pressure (CPAP) is used in babies who can breathe adequately by themselves but whose breathing is better and easier if small pressures are applied to help prevent airspace collapse. Mechanical ventilation (breathing machines) are used for babies who cannot breathe adequately on their own. Surfactant therapy supplies the baby with the missing material for a few days until its own lung cells mature. Surfactant improves breathing and lessens the chances of lung rupture. In most premature babies, surfactant is administered soon after birth without waiting to determine how severe the RDS is going to get. In more hardy premature babies, surfactant is given only if RDS becomes severe.
Complications:
A broken leg is put in a cast and not used until it heals, however; a lung has to continue to function even when it is “broken.” Sometimes there are tears in the lung causing air to escape into the chest cavity, a condition called pneumothorax. This air can even invade the lung tissue, a condition called pulmonary interstitial emphysema, or PIE. Occasionally, babies with RDS have bleeding into their lungs. Prematurely born babies face many dangers and RDS is often not their only problem. Obviously, these fragile patients are in greater peril if they have multiple problems, and multiple problems make each individual problem more difficult to successfully manage.
Outlook:
With modern therapy, death from RDS is rare in all but the tiniest babies or babies with multiple problems. However, many babies who survive severe RDS have prolonged breathing problems that can last for months, called bronchopulmonary dysplasia (BPD) or chronic lung disease (CLD).
Administration of exogenous surfactants, including INFASURF, often rapidly improve oxygenation and lung compliance. Following INFASURF administration, patients should be monitored so that oxygen and ventilatory support can be modified. During dosing with INFASURF, the most common adverse reactions reported in clinical trials were cyanosis (65%), airway obstruction (39%), bradycardia (34%), and ETT reflux (21%). These events were generally transient, and not associated with serious complications. If any of these events occur, administration should be interrupted and the infant's condition stabilized.