Feasibility and Effect of Physiological-Based CPAP in Preterm Infants at Birth

Abstract

Background: Preterm infants are commonly supported with 5-8 cmH₂O CPAP. However, animal studies demonstrate that high initial CPAP levels (12-15 cmH₂O) which are then reduced (termed physiological based (PB)-CPAP), improve lung aeration without adversely affecting cardiovascular function. We investigated the feasibility of PB-CPAP and the effect in preterm infants at birth. Methods: Preterm infants (24-30 weeks gestation) were randomized to PB-CPAP or 5-8 cmH₂O CPAP for the first 10 min after birth. PB-CPAP consisted of 15 cmH₂O CPAP that was decreased when infants were stabilized (heart rate ≥100 bpm, SpO₂ ≥85%, FiO₂ ≤ 0.4, spontaneous breathing) to 8 cmH₂O with steps of ~2/3 cmH₂O/min. Primary outcomes were feasibility and SpO₂ in the first 5 min after birth. Secondary outcomes included physiological and breathing parameters and short-term neonatal outcomes. Planned enrollment was 42 infants. Results: The trial was stopped after enrolling 31 infants due to a low inclusion rate and recent changes in the local resuscitation guideline that conflict with the study protocol. Measurements were available for analysis in 28 infants (PB-CPAP n = 8, 5-8 cmH₂O n = 20). Protocol deviations in the PB-CPAP group included one infant receiving 3 inflations with 15 cmH₂O PEEP and two infants in which CPAP levels were decreased faster than described in the study protocol. In the 5-8 cmH₂O CPAP group, three infants received 4, 10, and 12 cmH₂O CPAP. During evaluations, caregivers indicated that the current PB-CPAP protocol was difficult to execute. The SpO₂ in the first 5 min after birth was not different [61 (49-70) vs. 64 (47-74), p = 0.973]. However, infants receiving PB-CPAP achieved higher heart rates [121 (111-130) vs. 97 (82-119) bpm, p = 0.016] and duration of mask ventilation was shorter [0:42 (0:34-2:22) vs. 2:58 (1:36-6:03) min, p = 0.020]. Infants in the PB-CPAP group required 6:36 (5:49-11:03) min to stabilize, compared to 9:57 (6:58-15:06) min in the 5-8 cmH2O CPAP group (p = 0.256). There were no differences in short-term outcomes. Conclusion: Stabilization of preterm infants with PB-CPAP is feasible but tailoring CPAP appeared challenging. PB-CPAP did not lead to higher SpO₂ but increased heart rate and shortened the duration of mask ventilation, which may reflect faster lung aeration.

Keywords: CPAP; birth; physiology; preterm; respiratory support.

Figure 1

Physiological-based CPAP.

Figure 2

Consort 2010 flowchart.

Figure 3

Physiological outcomes. Physiological outcomes oxygen saturation [SpO₂, (A)], fraction of inspired oxygen [FiO₂, (B)], heart rate (C) and time that heart rate exceeds 100 bpm (D) of infants receiving PB-CPAP and 5–8 cmH₂O CPAP following the per-protocol analysis. In (D), heart rate >100 bpm is illustrated as the incidence over time (continuous line) with the median group time (dotted vertical line) and (shaded) inter quartile range.

Figure 4

Outcomes of respiratory effort. Outcomes of respiratory effort breathing rate (A), inspiratory tidal volume [Vti, (B)] and minute volume [MV, (C)] of infants receiving PB-CPAP and 5-8 cmH₂O CPAP following the per-protocol analysis.

Figure 5

Mean airway pressure and leak. Mean airway pressure (A) and leak (B) per respiratory support mode. Leak per respiratory support mode is calculated as difference in leak compared to 5–8 cmH₂O CPAP as it is calculated within infants. Asterisk indicates significant difference.