Chronic lung disease (CLD) comes as a result of lung injury. The likelihood of CLD occurring is influenced by events during pregnancy or birth, the degree of immaturity, the underlying lung condition, exposure of the lung to supplemental oxygen, the use of mechanical ventilation, and the presence of infection. The longer a baby needs supplemental oxygen and mechanical ventilation, the more likely it is that she will develop CLD.
About 50% of extremely premature babies who have respiratory distress syndrome (RDS) will have CLD to some degree. In many ways, CLD is the price to pay for surviving respiratory distress and other lung complications. Luckily, severe cases are rare and most babies grow to maturity without major long-term complications.As the lungs attempt to repair the damage associated with the RDS treatment, the force of the ventilator and the extra oxygen can interfere with the healing process.
The treatment goal with CLD is to maintain an acceptable oxygen level in the blood without causing further lung damage.
Babies with CLD may not be mechanically ventilated. If a baby with CLD is ventilated, because ventilation is partly to blame for the lung injury, babies with CLD will be weaned off mechanical ventilation as quickly as possible. In some cases, this may mean tolerating a higher level of carbon dioxide than normal. Called permissive hypercapnea, this approach is used to prevent further lung damage and encourage spontaneous breathing.
Babies with CLD may also be managed with one or more of the following approaches:
- diuretics, which are medications that encourage urination and therefore help maintain a proper fluid balance
- bronchodilators, which may encourage the airways to stay open
- steroids, which may decrease inflammation in the airways
- mechanical ventilation
- antibiotics, if there is suspected or proven infection in the lung
CLD and bronchopulmonary dysplasia
The terms CLD and bronchopulmonary dysplasia (BPD) are at times used to describe the same lung condition, although there are differences.
Although in both conditions scar tissue has formed in the lungs, with BPD the fibrosis created by the scarring will generally not heal normally; this will cause the lung to become quite stiff. Additionally, babies with BPD are at a higher risk for heart problems, specifically cor pulmonale or a failure of the right ventricle of the heart. Thankfully, BPD is rare.
Although CLD cannot always be avoided through careful use of ventilation technologies, the damage caused, though similar to that of BPD, is not necessarily permanent. Babies with established CLD are often treated with supplemental oxygen and may sometimes go home needing oxygen for a few weeks or months.