Nasal respiratory support and tachypnea and oral feeding in full-term newborn lambs.

Newborn infants with respiratory difficulties frequently require nasal respiratory support such as nasal continuous positive airway pressure (nCPAP) or high-flow nasal cannulae (HFNC). Oral feeding of these infants under nasal respiratory support remains controversial out of fear of aspiration and cardiorespiratory events. The main objective of this study was to evaluate the safety of oral feeding under different types of nasal respiratory support in newborn lambs without or with tachypnea. Eight lambs aged 4-5 days were instrumented to record sucking, swallowing, respiration, ECG, oxygen saturation, and arterial blood gases. Each lamb was given two bottles of 30 mL of milk with a pause of 30 s under videofluoroscopy in four conditions [no respiratory support, nCPAP 6 cmHO, HFNC 7 L/min, HFNC (= HFNC 7 L/min + CPAP 6 cmHO)] administered in random order. The study was conducted in random order over 2 days, with or without standardized tachypnea induced by thoracic compression with a blood pressure cuff. Generalized linear mixed models were used to compare the four nasal respiratory supports in terms of safety (cardiorespiratory events and aspiration), sucking-swallowing-breathing coordination, and efficacy of oral feeding. Results reveal that no nasal respiratory support impaired the safety of oral feeding. Most of the few laryngeal penetrations we observed occurred with HFNC. Nasal CPAP modified sucking-swallowing-breathing coordination, whereas the efficiency of oral feeding decreased under HFNC. Results were similar with or without tachypnea. In conclusion, oral feeding under nasal respiratory support is generally safe in a term lamb, even with tachypnea. The practice of orally feeding newborns suffering from respiratory problems while on nCPAP or HFNC remains controversial for fear of triggering cardiorespiratory events or aspiration pneumonia, or aggravating chronic lung disease. The present results show that bottle-feeding is generally safe in full-term lambs under nasal respiratory support, both without and with tachypnea.