330 - Does Nasal Respiratory Support Decrease Gastroesophageal Reflux in Preterm Lambs?

Poster Number: 330
Publication Number: 330.345

Basma Fathi. Elsedawi, Université de Sherbrooke, Faculté de Médecine, Sherbrooke, PQ, Canada; Djamal Djeddi, Universite de Sherbrooke Faculty of Medicine, Amiens, Picardie, France; Nathalie Samson, University of Sherbrooke, Sherbrooke, PQ, Canada; Arianne Charette, Universite de Sherbrooke Faculty of Medicine, Sherbrooke, PQ, Canada; Alexandra Nica, Universite de Sherbrooke Faculty of Medicine, Sherbrooke, PQ, Canada; Sarah-Gabrielle Taillandier-Pensarini, Universite de Sherbrooke Faculty of Medicine, Eastman, PQ, Canada; Jean-Paul Praud, University of Sherbrooke, Sherbrooke, PQ, Canada

Background: Gastroesophageal reflux (GER) is universal in newborns and may have cardiorespiratory consequences in certain preterm infants. We have previously shown that nasal continuous positive airway pressure (nCPAP) and other forms of nasal positive pressure ventilation inhibit GER in full-term lambs (Cantin D. et al., 2016; Djeddi D. et al., 2014), complementing similar results in adult humans (Tamanna S. et al., 2016; Tawk M. et al., 2006). However, the effect of high flow nasal cannulas (HFNC), another form of nasal respiratory support, remains unknown in newborns.

Objective:

We aim to compare the effects of nCPAP and HFNC on GER in preterm lambs.

Hypothesis: nCPAP, but not HFNC, inhibits GERs in preterm lambs.

Design/Methods:

Eleven preterm lambs born 14 days before full-term (~ at 34 weeks of human gestation) were studied. Esophageal pH-Impedance and polysomnography recordings were performed simultaneously for six hours. Recordings were performed during three randomly ordered conditions: nCPAP 6 cmH₂O, HFNC 7 L/min, and no respiratory support. The number of GERs was analysed during each condition. Statistical analysis was performed using Friedman test and ad hoc post-test as needed.

Results:

The number of GERs in control condition was higher in preterm lambs than previously observed in full-term lambs, i.e., 25 ± 22 vs. 9 ± 9 (Djeddi D. et al., 2014). Overall, contrarily to results in full-term lambs, nCPAP did not decrease the number of GERs; in addition, no differences were observed between the 3 tested conditions (P = 0.4). Both nCPAP and HFNC had a variable effect on GER number. Nasal CPAP decreased GERs in 3 lambs, increased GERs in 3 lambs and did not change GERs in 5 lambs. HFNC decreased GERs in 4 lambs, increased GERs in 5 lambs and did not change GERs in 2 lambs (figure 1).

Conclusion(s):

Contrary to full-term lambs, both nasal CPAP and HFNC have a variable effect on GERs in preterm lambs. Potential explanations, such as a more immature esogastric junction or more frequent gastric distension, will have to be tested in future studies.