Respiratory Distress in Newborns: Definition
Respiratory distress in newborns is defined by the presence of abnormal breathing patterns manifesting as tachypnea (respiratory rate >60 breaths/minute), along with any combination of grunting, nasal flaring, retractions (intercostal, subcostal, or suprasternal), head nodding, tracheal tugging, and/or cyanosis. 1, 2
Core Clinical Signs
The key clinical features that define respiratory distress include:
- Tachypnea: Respiratory rate exceeding 60 breaths per minute in term newborns 1, 2
- Grunting: Repetitive "eh" sounds during early expiration against a partially closed glottis, representing the infant's attempt to generate positive end-expiratory pressure and maintain lung volume 3
- Nasal flaring: Consistent and repetitive outward movement of the ala nasi during inspiration, representing the infant's attempt to reduce inspiratory resistance 3
- Retractions: Inward pulling of the chest wall tissues (intercostal, subcostal, or suprasternal) during inspiration, occurring due to more negative intrapleural pressures needed to maintain tidal volumes 3, 1
- Cyanosis: Blue discoloration indicating inadequate oxygenation 1, 2
Signs of Severe Respiratory Distress
When evaluating newborns, clinicians must distinguish between mild chest indrawing alone versus severe respiratory distress, as the latter carries significantly higher mortality risk and requires immediate intervention. 3 Signs indicating severe respiratory distress include:
- Head nodding: The head moves upward and downward in synchrony with respiration due to bilateral retraction of sternocleidomastoid and scalene muscles, most visible in young infants with limited head control 3
- Tracheal tugging: Soft tissue over the trachea immediately superior to the sternum pulls inward during inspiration 3
- Persistent nasal flaring: Continuous rather than intermittent flaring 3
- Severe tachypnea: ≥70 breaths/minute in infants 2-11 months or ≥60 breaths/minute in children 12-59 months 3
- Pronounced lower chest wall indrawing: More severe than simple chest indrawing 3
- Stridor while calm: Indicates significant airway obstruction 3
Age-Specific Considerations
In infants younger than 2 years, chest indrawing alone has decreased specificity for serious respiratory disease because their chest wall is nearly 3 times more compliant than their lungs due to immature bone ossification. 3 This means chest indrawing can occur with:
- Mildly increased upper airway resistance from nasopharyngeal inflammation 3
- Nonrespiratory diseases with high metabolic demands (e.g., febrile illnesses) 3
However, when chest indrawing occurs with signs of severe respiratory distress or hypoxemia (SpO₂ <90-93%), it becomes highly specific for pulmonary disease and substantially increases mortality risk. 3
Objective Measurements
Beyond clinical signs, respiratory distress assessment should include:
- Pulse oximetry: Hypoxemia defined as SpO₂ <93% (adjusted for altitude using reference population norms) 3
- Respiratory rate: Counted over a full minute, as brief spot checks are insufficient 4
- Blood gas analysis: May reveal hypoxemia, hypercapnia, and mixed acidosis 5
Critical Pitfall to Avoid
Do not rely on brief spot checks or single assessments—continuous monitoring in various states (rest, sleep, feeding, activity) is essential for accurate evaluation of respiratory distress severity. 4 The presence of severe respiratory distress signs indicates higher likelihood of respiratory decompensation and requires immediate escalation of care. 3