From the Guidelines
Bronchopulmonary dysplasia (BPD) is diagnosed based on the need for supplemental oxygen at specific time points in premature infants, with the most recent and widely accepted criteria defining BPD as oxygen requirement at 36 weeks postmenstrual age (PMA) or at 28 days of life, with severity grading based on the level of respiratory support needed 1.
Diagnosis Criteria
The diagnosis of BPD is based on several criteria, including:
- Oxygen requirement at 36 weeks postmenstrual age (PMA) or at 28 days of life
- Severity grading based on the level of respiratory support needed, such as:
- Mild BPD: breathing room air at 36 weeks PMA but requiring oxygen earlier
- Moderate BPD: requiring less than 30% oxygen at 36 weeks
- Severe BPD: requiring either 30% or more oxygen or positive pressure ventilation at 36 weeks PMA
Gestational Age Considerations
For infants born at less than 32 weeks gestation, the assessment is made at 36 weeks PMA, while for infants born at 32 weeks or later, assessment is made at 56 days postnatal age or discharge, whichever comes first 1.
Management Strategies
Early identification of BPD using these criteria helps guide appropriate management strategies, including:
- Gentle ventilation
- Oxygen targeting
- Nutritional support
- Consideration of medications like caffeine, diuretics, or corticosteroids in specific situations
Pathophysiology
The underlying pathophysiology of BPD involves disrupted alveolar and vascular development due to inflammation, oxidative stress, and mechanical ventilation, leading to decreased alveolarization and abnormal pulmonary vasculature 1.
From the Research
Criteria for Bronchopulmonary Dysplasia
The criteria for diagnosing bronchopulmonary dysplasia (BPD) have evolved over time, with a focus on the level and duration of oxygen therapy and respiratory support. Key points to consider include:
- The definition of BPD that best predicts early childhood morbidity categorizes disease severity according to the mode of respiratory support administered at 36 weeks' postmenstrual age, regardless of supplemental oxygen use 2.
- The diagnostic criteria for BPD can be defined according to treatment with the following support at 36 weeks' postmenstrual age:
- No BPD: no support
- Grade 1: nasal cannula ≤2 L/min
- Grade 2: nasal cannula >2 L/min or noninvasive positive airway pressure
- Grade 3: invasive mechanical ventilation 2.
- These criteria correctly predicted death or serious respiratory morbidity in 81% of study infants, with rates of this outcome increasing stepwise from 10% among infants without BPD to 77% among those with grade 3 disease 2.
Grading of BPD Severity
The severity of BPD can be graded based on the level of respiratory support required, with higher grades indicating more severe disease. The grading system includes:
- Mild BPD: minimal respiratory support required
- Moderate BPD: moderate respiratory support required
- Severe BPD: significant respiratory support required, including invasive mechanical ventilation 3, 4.
- The 2001 consensus definition of BPD has adequate predictive capacity for lung function measured by spirometry at 4-6 years of age, with moderate-to-severe BPD being the best predictor of respiratory impairment 5.
Predictive Value of BPD Criteria
The predictive value of BPD criteria for lung function and respiratory outcomes has been evaluated in several studies. Key findings include:
- The diagnostic criteria for BPD that categorize disease severity according to the mode of respiratory support administered at 36 weeks' postmenstrual age have adequate predictive capacity for lung function measured by spirometry at 4-6 years of age 5.
- Moderate-to-severe BPD is an independent risk factor for lung function impairment, with greater impairment of lung function observed in children with moderate-to-severe BPD compared to those with mild BPD or no BPD 5.