From the Guidelines
Tachypnea is the key abnormality that helps identify children with acute respiratory distress caused by lung tissue disease. When examining a child with respiratory distress, the presence of rapid breathing (tachypnea) strongly suggests parenchymal lung involvement rather than upper airway obstruction. Children with lung tissue disease typically present with increased respiratory rate, which is an early compensatory mechanism to maintain adequate oxygenation when the lungs are affected. This differs from upper airway obstruction, where stridor and retractions may be more prominent features. The degree of tachypnea often correlates with the severity of the underlying lung pathology. Tachypnea occurs because inflammation, infection, or other processes affecting the lung parenchyma reduce effective gas exchange, requiring faster breathing to maintain adequate oxygen levels.
According to the study by 1, tachypnea is a nonspecific clinical sign, but may represent a marker for respiratory distress and/or hypoxemia. The World Health Organization (WHO) defines pneumonia primarily as cough or difficult breathing and age-adjusted tachypnea: (age 2–11 months, ≥50/min; 1–5 years, ≥40/min; ≥5 years, >20 breaths/min). A study from a pediatric emergency department in Boston found that of children with WHO-defined tachypnea, 20% had confirmed pneumonia, compared with 12% without tachypnea 1.
Other supporting findings may include:
- Nasal flaring
- Grunting
- Retractions
- Decreased breath sounds
- Crackles
- Wheezing But tachypnea remains the most reliable and earliest indicator of lung tissue involvement in pediatric respiratory distress. The 2020 WHO guideline on drugs for COVID-19 also defines severe COVID-19 by any of the following: oxygen saturation <90% on room air, signs of pneumonia, or signs of severe respiratory distress, including very severe chest wall indrawing, grunting, central cyanosis, or presence of any other general danger signs in children 1.
In clinical practice, it is essential to consider tachypnea as a critical indicator of lung tissue disease in children with acute respiratory distress, as it can help guide management decisions and improve outcomes.
From the Research
Abnormality Identification in Acute Respiratory Distress
The abnormality that helps identify children with acute respiratory distress caused by lung tissue disease includes:
- Diffuse infiltrates on chest imaging, either plain radiography or computed tomography 2
- Pulmonary opacification on chest radiograph 3
- Ground-glass opacities in both lungs on chest CT scan 4
- Diffuse consolidations on chest CT scan 4
Imaging Modalities for Diagnosis
Various imaging modalities can be used to diagnose and manage acute respiratory distress syndrome (ARDS), including:
- Chest radiography 5, 2, 3, 6
- Computed tomography (CT) scans 5, 4, 2, 3, 6
- Bedside lung ultrasonography 6
- Radionuclide imaging 5
- MR imaging 5
Role of Imaging in ARDS
Imaging plays a crucial role in the diagnosis, management, and prognosis of ARDS, including: