Nasal continuous positive airway pressure inhibits gastroesophageal refluxes in the preterm lamb.

Gastroesophageal refluxes (GERs) are universal in newborns and may induce deleterious consequences, especially in preemies. We have previously shown that nasal continuous positive airway pressure (nCPAP) inhibits GERs in full-term lambs, complementing similar results in adult humans. The effect of high-flow nasal cannula (HFNC) on GERs, however, remains unknown. This study aimed to assess the effects of nCPAP and HFNC on GERs in our preterm lamb model. Eleven preterm lambs born 14 days before full-term (∼34 wk of human gestation) were studied. Esophageal pH-impedancemetry and polysomnography recordings were performed simultaneously for 6 h under three randomly ordered conditions: nCPAP 6 cmH2O, HFNC 7 L/min, and no respiratory support (control). The indexes (/h) of GERs and air-containing swallows were analyzed during each condition. The states of alertness and cardiorespiratory events were also analyzed during the identified GERs. nCPAP significantly decreased the GER index compared with control and HFNC during both quiet wakefulness and nonrapid eye movement sleep, whereas HFNC did not alter the GER index. In addition, nCPAP significantly increased the air-containing swallow index compared with control and HFNC. No significant differences were observed between the tested conditions for GER-related cardiorespiratory events, which were nevertheless rarely observed. Similar to full-term lambs, nCPAP strongly inhibited GERs in the preterm lamb, despite an increase in air-containing swallows. In contrast, HFNC did not impact GERs. Our results are clinically relevant when discussing the use of CPAP in preemies with GERs.NEW & NOTEWORTHY Nasal CPAP inhibited gastroesophageal refluxes in preterm lambs, despite increasing air-containing swallows. High-flow nasal cannula did not impact GERs. Nasal respiratory support did not alter the rare cardiorespiratory events observed during GERs.