Page 126 - Physiological based CPAP for preterm infants at birth Tessa Martherus

Chapter 5
Feasibility of the current PB-CPAP strategy
Protocol adherence
Protocol adherence could not be evaluated in all infants due to technical errors. Protocol adherence was evaluated in 7/8 infants of the PB-CPAP group and three minor protocol deviations were found. One infant received three inflations with a PEEP of 15 cmH2O and in two infants CPAP was decreased faster than described in the study protocol. When protocol adherence was evaluated in 18/20 infants of the 5-8 cmH2O group, it was found that three infants received a CPAP/PEEP level of 4, 10 and 12 cmH2O unintentionally for several minutes.
Post-trial evaluations
Evaluations showed that although all caregivers supported the concept of PB-CPAP, only a few (3/11) felt comfortable in performing the protocol. While caregivers often use CPAP, monitor parameters and adjust settings (e.g. FiO2), the PB-CPAP protocol was considered too complex using existing equipment due to the many predefined actions and evaluation moments. If infants became apneic, CPAP was decreased from 15 to 8 cmH2O during iPPV, increased back to 15 cmH2O once CPAP was continued and was decreased step-wise to 8 cmH2O once infants were stabilized. Caregivers indicated that it was challenging to perform these CPAP changes while providing stabilisation and a dedicated person (who focused on CPAP) was required to ensure protocol adherence.
Effects of PB-CPAP
Effect on Physiological parameters (Table 2)
The SpO2 in the first 5 min after birth was not significantly different between groups in the per-protocol (PB-CPAP vs 5-8 cmH2O CPAP, 61 (49-70) vs 64 (47-74)%, variance of random intercept 128.7, variance of residual 307.3, p=0.973, Figure 3A) and the intention-to-treat analysis (62 (52-70) vs 64 (47-74)%, variance of random intercept 123.3, variance of residual 305.9, p=0.992, supplementary table). There were no significant differences between groups in SpO2 (Figure 3A), FiO2 (Figure 3B) and the SpO2/FiO2 ratio. However, infants supported with PB-CPAP achieved significantly higher heart rates in the first 5 min (121 (111-130) vs 97 (82-119) bpm, p=0.016) and tended to have higher heart rates in the first 10 min after birth (135 (127-141) vs 123 (107-136) bpm, p=0.075) (Figure 3C). Infants stabilized with PB-CPAP required significantly less time to achieve a stable heart rate >100 bpm (03:01 (01:40-03:19) vs 04:13 (02:25-05:07) min, p=0.009, Figure 3D).
Effect on respiratory effort (Table 2)
The groups showed no significant differences regarding breathing rate (37 (20-42) vs 28 (24-33) breaths/min, p=0.458, Figure 4A), tidal volume (2.6 (2.4-4.0) vs 2.9 (0.6-6.0) mL/kg, p=0.929, Figure 4B) and minute volume (120 (62-187) vs 114 (24-212) mL/kg/min, p=1.000, Figure 4D). There were no differences in inter-breath interval variability or peak inspiratory flow rate.
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