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

Objective Nasal high-frequency oscillatory ventilation (nHFOV) and synchronized nasal intermittent positive pressure ventilation (sNIPPV) yield a lower partial pressure of carbon dioxide (pCO(2)) 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 pCO(2) 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 pCO(2) levels were measured after 2 hours in each mode. Subgroup analyses were performed for preterm (gestational age <37 weeks) and very preterm (gestational age <32 weeks) neonates. Results The mean gestational age (nHFOV-sNIPPV, 32.8 vs. sNIPPV-nHFOV, 33.5 weeks) and median birthweight (1,850 vs. 1,930 g) did not differ between the sequences. The mean +/- standard deviation pCO(2) level after nHFOV (38.7 +/- 8.8mm Hg) was significantly higher than that after sNIPPV (36.8 +/- 10.2mm Hg; mean difference: 1.9mm Hg; 95% confidence interval: 0.3-3.4mm Hg; treatment effect [p = 0.007] but no sequence [p = 0.92], period [p = 0.53], or carryover [p = 0.94] effects). However, the difference in pCO(2) level between the sequences was not statistically significant in the subgroup analyses of preterm and very pretermneonates. Conclusion After neonatal extubation, the sNIPPV mode was associated with a lower pCO(2) level than the nHFOV mode with no significant difference in preterm and very preterm neonates.