Background: Nose and mouth leaks impair effective pressure transmission during neonatal continuous positive airway pressure (CPAP), but little is known about how these leaks affect physiological parameters. This study investigated the influence of nose leaks and spontaneous mouth opening on peripheral oxygen saturation (SpO₂) and respiratory rate (RR) using nasopharyngeal CPAP.
Methods: In 32 neonates with a gestational age of 30 (24-38) weeks and a birth weight of 1435 (710-2730) g, SpO₂ and RR measurements were taken with and without occlusion of the contralateral nostril in a randomized cross-over trial in 1-minute intervals over a 10-minute period during each condition. Mouth opening and newborn activity were documented.
Results: SpO₂ with open nostril was comparable to that with occluded nostril [93 (78.5-99.5)% vs. 94 (80-100)%, P=0.20]. RR decreased from 51 (26-82)/min to 48 (32-85)/min (P=0.027). In infants with an SpO₂ ≤ 93% during open nostril (n=17), SpO₂ increased after nostril occlusion [91 (80-96)% vs. 89.5 (78.5-93)%, P=0.036]. The mouth was open in 78.5% of measurements with open nostril, and in 87.4% of measurements after nostril occlusion (P=0.005). No significant influence of mouth opening or closure on SpO₂ or RR was detected.
Conclusions: In neonates on unilateral nasopharyngeal CPAP with an SpO₂ ≤ 93%, occlusion of the contralateral nostril significantly increased SpO₂ and reduced RR. The beneficial physiological effects further support using binasal prongs to minimize nose leaks in this population. Future studies should investigate the beneficial effects of reducing mouth leaks when applying CPAP to these infants.