NRP Preterm Infant Resuscitation 2 — Questions and Answers
Question 1: What is the risk of providing excessive tidal volumes during PPV in a preterm infant, and how can this be mitigated?
- Excessive tidal volumes cause hypocapnia but have no structural lung effects
- Volutrauma from excessive tidal volumes causes alveolar overdistension and inflammatory lung injury, increasing risk of bronchopulmonary dysplasia (Correct answer)
- Excessive tidal volumes increase pulmonary vascular resistance and worsen PPHN
- Excessive tidal volumes reduce surfactant production in the immature lung
Correct answer: Volutrauma from excessive tidal volumes causes alveolar overdistension and inflammatory lung injury, increasing risk of bronchopulmonary dysplasia
Volutrauma — lung injury from excessive tidal volumes — causes alveolar overdistension, epithelial disruption, and inflammatory mediator release that can lead to bronchopulmonary dysplasia (BPD) in preterm infants.
Preterm lungs are structurally immature with fewer alveoli and less compliant but more fragile walls. Excessive tidal volumes cause volutrauma — overdistension of alveoli leading to mechanical disruption of the epithelial barrier, activation of inflammatory cascades, and release of cytokines that injure the developing lung. Chronic volutrauma is a major contributor to bronchopulmonary dysplasia (BPD), the most common serious complication of preterm birth. To mitigate this risk, NRP recommends using the lowest effective PIP and PEEP, titrating ventilation to visible chest rise (described as a 'gentle wiggle of the chest' — not exaggerated movement), and using volume-targeted modes of ventilation in the NICU. Pressure gauges (manometers) and T-piece resuscitators help control PIP.
Question 2: What is the rationale for using antenatal corticosteroids before preterm delivery, and how do they affect delivery room management?
- Corticosteroids prevent infection in the preterm infant by boosting the immune system
- Antenatal corticosteroids accelerate fetal lung maturation and surfactant production, reducing the severity of RDS and the need for delivery room interventions (Correct answer)
- Corticosteroids increase fetal heart rate to improve oxygenation before birth
- Antenatal corticosteroids have no proven benefit if given less than 48 hours before delivery
Correct answer: Antenatal corticosteroids accelerate fetal lung maturation and surfactant production, reducing the severity of RDS and the need for delivery room interventions
Antenatal corticosteroids (betamethasone or dexamethasone) administered 24–48 hours before preterm delivery significantly accelerate lung maturation, increase surfactant production, and reduce the incidence and severity of RDS, IVH, and NEC.
Administration of antenatal corticosteroids to mothers at risk for preterm delivery before 34 weeks gestation is one of the most effective interventions in perinatal medicine. Betamethasone (preferred) or dexamethasone crosses the placenta and accelerates type II pneumocyte maturation, increasing surfactant synthesis and secretion. This leads to: reduced incidence and severity of RDS, lower rates of IVH, NEC, and neonatal mortality, reduced need for surfactant replacement therapy, and less need for intubation in the delivery room. Full benefit requires at least 24 hours; partial benefit is seen even with shorter intervals. This information should be communicated to the NRP team — a preterm infant who received full antenatal steroids is clinically different from one who received none.
Question 3: What is 'gentle' chest rise in the context of PPV for preterm infants, and why is it important?
- Chest movement barely perceptible — any visible movement indicates excessive tidal volume
- Slight, visible chest rise described as a gentle movement of the chest — indicates appropriate tidal volume without overdistension (Correct answer)
- Vigorous chest expansion to ensure adequate tidal volume delivery
- Chest rise equivalent to that seen in a normal adult breath
Correct answer: Slight, visible chest rise described as a gentle movement of the chest — indicates appropriate tidal volume without overdistension
NRP recommends aiming for slight, visible chest rise ('a gentle wiggle') during PPV for preterm infants. Excessive chest rise indicates high tidal volumes that risk volutrauma and BPD.
Because preterm lungs are highly compliant but fragile, the tidal volume needed to achieve adequate ventilation is relatively small. NRP describes the goal of PPV as producing 'gentle chest rise' — a subtle, visible movement of the chest wall, sometimes described as a 'gentle wiggle.' Exaggerated chest excursion indicates that pressures or volumes are excessive, creating risk of volutrauma and subsequent lung injury. Visual assessment of chest rise, combined with monitoring of peak inspiratory pressure on a manometer, is used to titrate ventilation appropriately. This principle reinforces the importance of using the minimum effective pressure and volume to achieve adequate ventilation.
Question 4: Which of the following methods can help prevent cold stress in a preterm infant less than 32 weeks in the delivery room?
- Vigorous drying followed by warm blankets
- Polyethylene wrap, prewarmed delivery room (25–26°C), prewarmed radiant warmer, and chemical warming mattress (Correct answer)
- Oral glucose to prevent metabolic cold response
- Immediate intubation to allow warming via heated humidified gases
Correct answer: Polyethylene wrap, prewarmed delivery room (25–26°C), prewarmed radiant warmer, and chemical warming mattress
A bundle of interventions is recommended: polyethylene wrap/bag (without drying), prewarmed radiant warmer, room temperature ≥25–26°C, and a chemical warming mattress for the most premature infants.
Hypothermia in preterm infants is a major risk factor for adverse outcomes including IVH, sepsis, hypoglycemia, pulmonary hypertension, and mortality. Preventing hypothermia requires a systematic, multi-component approach: (1) Increase the delivery room ambient temperature to ≥25–26°C before delivery; (2) Pre-warm the radiant warmer; (3) Place the preterm infant (without drying) immediately into a polyethylene wrap or bag from the neck down; (4) Place on a chemical warming mattress (for infants <28 weeks); (5) Use a warm towel to cover the head if not wearing a cap; (6) Use heated humidified gases for ventilation when available. Temperature should be checked at 1 hour of age and regularly thereafter.
Question 5: At what gestational age is a preterm infant considered to have adequate thermal regulation without a polyethylene wrap?
- Less than 32 weeks
- 32–36 weeks (Correct answer)
- Greater than or equal to 36 weeks
- All preterm infants require polyethylene wrap regardless of gestational age
Correct answer: 32–36 weeks
NRP specifically recommends polyethylene wrap for infants less than 32 weeks. Infants 32–36 weeks have better thermoregulation and can be managed with standard drying and warm blankets, though individual assessment is needed.
The recommendation for polyethylene wrap is specifically targeted at infants less than 32 weeks gestation, who are at highest risk for hypothermia due to their very thin skin (minimal keratinization), high surface area-to-mass ratio, lack of subcutaneous fat, and immature thermoregulatory mechanisms. Infants between 32–36 weeks gestation have somewhat better thermoregulatory capacity and can typically be managed with standard approaches (drying and warm blankets under a radiant warmer). However, clinical judgment is always required, as factors such as prolonged exposure to cold, wet linens, or a cool delivery room can affect any preterm infant. The NRP guideline is clear: less than 32 weeks = polyethylene wrap.
Question 6: What is the NRP recommendation regarding oxygen use at the start of resuscitation for infants less than 35 weeks gestation?
- Start with 100% oxygen and wean based on SpO2
- Start with 21–30% oxygen and titrate to NRP SpO2 targets (Correct answer)
- Start with 50% oxygen for all preterm infants
- Use room air only (21%) as for term infants
Correct answer: Start with 21–30% oxygen and titrate to NRP SpO2 targets
For preterm infants less than 35 weeks, NRP recommends initiating resuscitation with 21–30% oxygen, using pulse oximetry to titrate FiO2 to age-appropriate SpO2 targets.
Preterm infants face the dual risks of hypoxia (due to immature lungs and surfactant deficiency) and hyperoxia (due to immature antioxidant defenses). NRP 8th edition balances these risks by recommending initial FiO2 of 21–30% for infants less than 35 weeks, with continuous pulse oximetry monitoring and active titration to the standard NRP SpO2 target table. This starting range provides a small buffer above room air to account for the higher likelihood that preterm infants will need some supplemental oxygen, while avoiding the oxidative injury associated with starting at 100%. Oxygen should be adjusted every 15–30 seconds based on SpO2 trends.
NRP Preterm Infant Resuscitation 2
What is the risk of providing excessive tidal volumes during PPV in a preterm infant, and how can this be mitigated?