Neonatal Respiratory Care Basics

The neonatal respiratory system differs fundamentally from the adult in anatomy, physiology, and vulnerabilities. Premature infants face challenges that do not exist in term newborns or older children: surfactant deficiency, immature respiratory control, highly compliant (and therefore easily damaged) lung parenchyma, and limited respiratory muscle endurance.

The respiratory therapist in the NICU must apply the same foundational RT skills used in adult ICU practice while adapting to dramatically different equipment scales, monitoring parameters, alarm thresholds, and pharmacological considerations. A tidal volume of 5 mL is appropriate for a 1 kg premature infant; it would be grossly insufficient for any adult patient.

Key NICU conditions RTs encounter: respiratory distress syndrome (RDS) from surfactant deficiency, transient tachypnea of the newborn (TTN), meconium aspiration syndrome (MAS), bronchopulmonary dysplasia (BPD) in former premature infants, congenital diaphragmatic hernia (CDH), and persistent pulmonary hypertension of the newborn (PPHN).

Oxygenation management in premature infants requires balancing two opposing risks that do not exist in the same way in adult care: hypoxemia (which causes immediate physiologic harm and can lead to pulmonary hypertension, brain injury, and death) and hyperoxemia (which causes retinopathy of prematurity, bronchopulmonary dysplasia, and oxidative organ injury).

Current recommendations for premature infants (<37 weeks corrected) generally target SpO₂ 90–95%. The specific range is protocol-dependent and may vary by gestational age, diagnosis, and institutional experience. Term newborns have different targets.

Key points for RT practice:

• Oxygen alarm limits in the NICU are typically narrow — both low and high SpO₂ alarms are clinically significant.
• Rapid SpO₂ fluctuations (intermittent hypoxemia events) are common in premature infants and require systematic assessment and documentation.
• FiO₂ adjustments in the NICU are often small increments (e.g., 2–5% at a time) due to high sensitivity to oxygen changes.
• Pulse oximetry probe placement and motion artifact are frequent issues in very small infants — verify the waveform before responding to an alarm.

Nasal CPAP (nCPAP) is the cornerstone of non-invasive respiratory support in premature infants and is often the first intervention after delivery room stabilization for infants with RDS. CPAP provides continuous distending pressure to the airways, preventing alveolar collapse between breaths and reducing the work of breathing.

In premature infants with surfactant-deficient lungs, CPAP maintains functional residual capacity and allows surfactant (both exogenous and endogenous) to work more effectively. The evidence-based INSURE approach (INtubate, SURfactant, Extubate back to CPAP) attempts to deliver surfactant while minimizing the duration of invasive mechanical ventilation.

CPAP delivery in the NICU can be provided via:

• Binasal prongs (most common for premature infants) — fit to nares with appropriate sizing
• Nasopharyngeal tube (single nasal prong inserted into nasopharynx)
• Infant nasal mask

Common CPAP pressures in neonatal practice: 4–8 cmH₂O, titrated based on clinical response, FiO₂ requirements, and degree of respiratory distress. Positioning (prone or elevated head) can influence CPAP effectiveness.

Pulmonary surfactant is the phospholipid-protein mixture produced by type II alveolar cells that reduces alveolar surface tension, preventing alveolar collapse at end-exhalation. Premature infants — particularly those born before 28–32 weeks gestation — have insufficient surfactant production, leading to diffuse atelectasis, respiratory distress syndrome, and severe hypoxemia.

Exogenous surfactant preparations (beractant, calfactant, poractant alfa) are administered intratracheally — typically by the respiratory therapist under physician direction. The procedure involves:

• Confirming ETT position and patent airway before instillation
• Dividing the dose into aliquots instilled in different positions (or as a bolus, depending on product and protocol)
• Monitoring for rapid compliance improvement — expected within minutes of administration
• Being prepared to reduce ventilator pressures or volumes immediately as compliance improves (failure to do so risks overdistension and air leak)
• Post-administration suctioning should be delayed for at least 1–2 hours to avoid washing out the surfactant

Apnea of prematurity (AOP) is one of the most common conditions managed in the NICU. Premature infants have immature respiratory control centers that produce irregular breathing patterns, periodic breathing, and apneic episodes — cessations of breathing lasting >20 seconds or associated with bradycardia (HR <100 bpm) or desaturation.

Types of neonatal apnea:

• Central apnea: absence of respiratory effort — most common in premature infants, reflects immature brainstem respiratory center.
• Obstructive apnea: respiratory effort present but airflow obstructed — may result from head position, secretions, or anatomic factors.
• Mixed apnea: combination of central and obstructive components — most common type in clinical practice.

Management strategies include gentle tactile stimulation, CPAP (reduces obstructive component), caffeine citrate (methylxanthine therapy — the pharmacological standard for AOP), and in severe cases, intubation and mechanical ventilation. RTs often respond to ABD events as part of routine NICU practice — assess responsiveness to stimulation, adequacy of airway positioning, and whether the event is self-resolving or requires intervention.

Neonatal mechanical ventilation aims to achieve adequate gas exchange while minimizing lung injury — volutrauma, barotrauma, atelectrauma, and biotrauma from repeated inflammatory cycles. The developing neonatal lung is significantly more vulnerable to ventilator-induced injury than the mature adult lung.

Core principles of gentle neonatal ventilation:

• Tidal volume targeting: 4–6 mL/kg body weight — significantly lower than adult lung-protective targets. Many modern neonatal ventilators offer volume-targeted modes specifically designed for this population.
• Permissive hypercapnia: Accepting moderately elevated PaCO₂ (45–55 mmHg range, per protocol) to avoid excessive ventilatory pressures. Severe hyperventilation causes cerebral vasoconstriction and increases risk of intraventricular hemorrhage in premature infants.
• Minimal FiO₂: Target the minimum FiO₂ needed to maintain SpO₂ in the goal range. Wean rapidly after surfactant or CPAP placement when clinically appropriate.
• Lung-open strategy: Adequate PEEP to maintain alveolar recruitment without overdistension. In surfactant-deficient lungs, higher PEEP (5–7 cmH₂O) may be required.
• Minimize duration: Early extubation to CPAP or non-invasive support is a primary goal. Every additional day of invasive ventilation increases risk of BPD and other complications.