Carbon Dioxide Level between Nasal High-Frequency Oscillatory Ventilation and Synchronized Nasal Intermittent Positive Pressure Ventilation after Extubation in Neonates: A Cross-over Randomized Controlled Trial

Abstract

Objective Nasal high-frequency oscillatory ventilation (nHFOV) and synchronized nasal intermittent positive pressure ventilation (sNIPPV) yield a lower partial pressure of CO2 (pCO2) after extubation than nasal continuous positive airway pressure. Our aim was to clarify which of the two was superior. Study Design We performed a crossover randomized study to evaluate pCO2 level among 102 participants from July 2020 to June 2022. Intubated preterm and term neonates with arterial lines were randomly allocated to nHFOV-sNIPPV or sNIPPV-nHFOV sequences; their pCO2 levels were measured after 2 h in each mode. Subgroup analyses were performed for preterm (gestational age <37 weeks) and very preterm (gestational age <32 weeks) neonates. <b>Results </b>The mean gestational age (nHFOV-sNIPPV, 32.8 vs sNIPPV-nHFOV, 33.5 weeks) and median birth weight (1,850 vs 1,930 g) did not differ between the sequences. The mean ± standard deviation pCO<sub>2</sub> level after nHFOV (38.7 ± 8.8 mmHg) was significantly higher than that after sNIPPV (36.8 ± 10.2 mmHg; mean difference: 1.9 mmHg; 95% confidence interval: 0.3–3.4; treatment effect [<i>p</i> = 0.007] but no sequence [<i>p</i> = 0.92], period [<i>p</i> = 0.53], or carryover [<i>p</i> = 0.94] effects). However, the difference of pCO<sub>2</sub> level between the sequences was not statistically significant in the subgroup analyses of preterm and very preterm neonates. <b>Conclusion</b> After neonatal extubation, the sNIPPV mode was associated with a lower pCO<sub>2</sub> level than the nHFOV mode with no significant difference in preterm and very preterm neonates.