Once the risk period for retinopathy has passed, oxygen therapy is indicated when the SaO2 on room air is 92% or less. It should be considered in patients with a SaO2 between 93% and 96% if there are signs of chronic lung disease and growth retardation despite adequate nutrition, and in patients with pulmonary hypertension (PH).

Chest computed tomography (CT) is the most sensitive test for the detection of lesions secondary to BPD. The characteristic findings of BPD are multifocal decreased attenuation, linear and subpleural opacities, bronchial wall thickening, bullae and emphysema, although no radiological pattern serves as a prognostic factor.8 High-resolution CT with four to six slices per test is recommended to minimise radiation exposure. Due to the exposure to radiation and to the use of sedation by many medical facilities, we recommend reserving this method for cases in which it could provide information relevant to the management of the patient.

The prevalence of PH in children with BPD ranges between 18% and 43%.9 Echocardiography is the recommended method for screening for PH. It should be performed in patients with oxygen dependence at 36 weeks of postmenstrual age or at 2 months of life (or in case of clinical worsening or increased oxygen or ventilatory support requirements),10 and in patients with a history of intrauterine growth restriction and insufficient weight gain.

In some facilities, patients that require pulmonary vasodilators undergo cardiac catheterisation for confirmation of PH. We believe that this invasive strategy should be reserved for severe cases that do not respond to vasodilator therapy or when cardiovascular anomalies are suspected.10,11

In severe cases, arterial blood gas analysis may need to be conducted prior to discharge to assess ventilation, although due to its invasiveness, blood gases are usually measured in capillary samples. Some degree of hypercapnia is commonly found.

It is recommended that a fibrobronchoscopy is performed in patients treated with long-term mechanical ventilation (MV) or with a tracheostomy to rule out granulomas or tracheal or subglottic stenosis secondary to long-term intubation or tracheostomy tube dwelling. Fibrobronchoscopy is also recommended if there is suspicion of laryngomalacia or tracheobronchomalacia.

Its assessment is restricted to specialty care facilities and it is still not part of routine evaluations due to its complexity, the lack of reference values and the need for sedation. The technique that offers the most information is rapid thoracoabdominal compression at tidal volume (maximal expiratory flow volume at functional residual capacity) and raised volume (forced vital capacity and forced expiratory volume). Plethysmography analyses the functional residual capacity, the total lung capacity and the residual volume. The analysis of breathing at tidal volume and pulmonary mechanics may also detect changes in respiratory status, although these tests are less sensitive.The results demonstrate a pattern of airflow obstruction with air trapping that tend to persist in time.12

The energy expenditure of patients with BPD is at least one third greater than in the rest of the preterm population, so these patients need a higher energy intake. Fluid overload must be avoided, with fluids provided only in the amount needed to ensure adequate diuresis.13 In patients in whom feeding is associated with increased respiratory effort or who fail to thrive, the option of nasogastric (NG) intubation and feeding must be assessed. If long-term NG feeding is likely or there are swallowing abnormalities that may facilitate pulmonary aspiration, the possibility of a gastrostomy should be evaluated.

The neurology department should assess these patients prior to discharge and determine whether they require follow-up by a rehabilitation team.

Refer to BPD treatment further down.

Respiratory morbidity is common in the first two years of life. It can include a broad range of disease, from severe cases requiring intensive care and oxygen therapy to cases that are completely asymptomatic. Patients may need oxygen therapy for months and frequent hospital care.17 They may suffer a slow and progressive deterioration in respiratory status, or have acute exacerbations that are almost always associated with viral infections or bronchial hyperresponsiveness. It is important to take preventive measures against deterioration and to detect it early. Food refusal, feeding fatigue, increases in respiratory rate and retractions are warning signs. Factors that may contribute to deterioration include fluid overload and cardiac decompensation (cor pulmonale), characteristic of severe cases of BPD. Measures must be taken to prevent infection by RSV in the community18 and to avoid potentially contagious environments such as childcare centres or scheduling hospital admissions for surgery during epidemic seasons.

If respiratory manifestations do not improve with standard treatment, gastroesophageal reflux (GER) should be ruled out, as it is more frequent in these patients than in other preterm infants, and may be exacerbated by air trapping. The risk of GER increases with theophylline use, NG intubation, and performance of gastrostomy prior to surgical correction of the reflux.

Nutritional care is a key factor in the prevention and subsequent management of BPD.19 These children usually have inadequate growth, which may result from undernutrition, suboptimal oxygenation, and increased energy expenditure.

It is essential that growth parameters be strictly monitored for at least the first year of life by means of specific follow-up programmes.

Children with BPD often feed poorly due to anorexia or fatigue resulting from breathing difficulties. If the child shows poor weight gain, nutrient intake and changes in feeding must be assessed, and parent cooperation and ruling out GER must be considered. On the other hand, rapid growth increases the risk of obesity and insulin resistance, so the goal is not to achieve weight gain rapidly, but for it to correspond to an increase in lean mass.

Slow weight gain is closely related to respiratory impairment. Marginal hypoxaemia has been proven to cause growth retardation, so adequate oxygenation must be achieved.

Neurodevelopmental impairment is more frequent in children with a history of BPD than in other PTNBs. The risk increases with prolonged MV, severe intraventricular haemorrhage (grade 3–4) and discharge past 43 weeks’ postmenstrual age.20 The impairment may affect visual and auditory perception, language, memory, the ability to learn and motor function. The prevalence of attention deficit disorder is higher in children with BPD.21 In addition, an association has been found between the early administration of systemic corticosteroids for treatment of BPD and long-term neurodevelopmental impairment.20

Vascular hypoplasia and damage to the pulmonary microvasculature associated with BPD can lead to PH. The diagnosis is usually made after 2 months of life when the infant has already been discharged. Thus, PH screening programmes should include two or three echocardiograms in the first year of life, and additional echocardiograms before and after supplemental oxygen is withdrawn.11

Children with BPD may develop arterial hypertension, the cause of which remains unclear.22 It typically starts between the second and fourth months following discharge, is usually mild and responds well to treatment. Arterial blood pressure should be measured periodically during the follow-up.

Left ventricular hypertrophy has been reported in some patients, sometimes in association with the use of dexamethasone.

Medication is generally used to manage respiratory symptoms, although there is not a broad consensus on the drugs to be used once the severe stage of the disease has passed.23 The treatment should be determined on a case-to-case basis based on respiratory manifestations, supplemental oxygen requirements and growth outcomes. Monitoring the treatment is important to establish its duration and watch for potential side effects.

Inhaled bronchodilators should only be used if an acute episode of airway obstruction is suspected and the patient shows a good response to therapy.24

The most commonly used bronchodilators are short-acting beta2 agonists with the same dosage and forms of administration used in patients with symptoms of bronchospasm. These drugs may cause a paradoxical response in children with associated tracheobronchomalacia.

Anticholinergic agents (ipratropium bromide) are weaker bronchodilators, and while their use is not recommended in children with BPD they can be administered following the guidelines for the treatment of asthma attacks.24

There is insufficient evidence of their effects on lung development or the management of airway obstruction, so they should be prescribed with caution.23,25 They may be useful for preventing recurrent episodes of wheezing following the guidelines for the treatment of asthma.

The main purpose of home oxygen therapy in children with BPD is treating chronic or intermittent hypoxaemia secondary to the disease. Supplemental oxygen improves weight gain,29,30 decreases airway resistance, increases lung compliance31 and reduces pulmonary hypertension.32 The incidence of sudden infant death syndrome and episodes of obstructive sleep apnoea is lower in children with oxygen saturations that remain above 93%.23

Along with postural changes, it aids the mobilisation of secretions and bronchial drainage in children with persistent atelectasis or thick secretions or on long-term MV. Different techniques are used, such as vibration, pressure on the chest and abdomen, exercises for pulmonary re-expansion, positioning for bronchial drainage, soft percussion, forced coughing and stimulation of the Vojta chest area.37

For home care, it is recommended that these methods continue to be applied in patients with severe disease, as chest physical therapy seems to have beneficial effects.38

The main purpose of nutritional support is to optimise growth and development. The feeding methods and composition of enteral formulas are subject of debate. Formulas specifically designed for premature infants must be used in order to deliver the right amount of calories, especially in the early months of life, and at times it is necessary to supplement with carbohydrates or fats. The use of mineral and vitamin supplements, required by all premature infants, must also be considered with care.23