Nasal continuous positive airway pressure influences bottle-feeding in preterm lambs

Study of Orofacial Function in Preschool Children Born Prematurely

Children born prematurely often exhibit orofacial dysfunction. We conducted Nordic Orofacial Test Screening and analyzed chewing and swallowing functions of 243 children aged 3−5 years, consisting of 142 and 101 children born full-term and preterm, respectively, to evaluate the orofacial function of preschool premature children. Categorical variables were analyzed using chi-square test for a comparison. The univariate analysis of variance was used to analyze the effects of birth weight, gestational age, intubation at birth, use of nasal continuous positive airway pressure support after birth, and use of nasogastric tube on the chewing and swallowing functions of children born prematurely. In this survey, term-born children had a higher incidence of bad oral habits, grinding teeth while sleeping, and abnormal gulping compared to preterm-born children. Preterm-born children had a higher incidence of choking, decreased mouth opening (<30 mm), abnormal dental arch form, abnormal palatal vault, and dysarthria compared to term-born children.

Safety of Bottle-Feeding Under Nasal Respiratory Support in Preterm Lambs With and Without Tachypnoea

Aim: Convalescing preterm infants often require non-invasive respiratory support, such as nasal continuous positive airway pressure or high-flow nasal cannulas. One challenging milestone for preterm infants is achieving full oral feeding. Some teams fear nasal respiratory support might disrupt sucking–swallowing–breathing coordination and induce severe cardiorespiratory events. The main objective of this study was to assess the safety of oral feeding of preterm lambs on nasal respiratory support, with or without tachypnoea.

Methods: Sucking, swallowing and breathing functions, as well as electrocardiogram, oxygen haemoglobin saturation, arterial blood gases and videofluoroscopic swallowing study were recorded in 15 preterm lambs during bottle-feeding. Four randomly ordered conditions were studied: control, nasal continuous positive airway pressure (6 cmH₂O), high-flow nasal cannulas (7 L•min^–1), and high-flow nasal cannulas at 7 L•min^–1 at a tracheal pressure of 6 cmH₂O. The recordings were repeated on days 7–8 and 13–14 to assess the effect of maturation.

Results: None of the respiratory support impaired the safety or efficiency of oral feeding, even with tachypnoea. No respiratory support systematically impacted sucking–swallowing–breathing coordination, with or without tachypnoea. No effect of maturation was found.

Conclusion: This translational physiology study, uniquely conducted in a relevant animal model of preterm infant with respiratory impairment, shows that nasal respiratory support does not impact the safety or efficiency of bottle-feeding or sucking–swallowing–breathing coordination. These results suggest that clinical studies on bottle-feeding in preterm infants under nasal continuous positive airway pressure and/or high-flow nasal cannulas can be safely undertaken.

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 cmH₂O, HFNC 7 L/min, HFNC_CPAP (= HFNC 7 L/min + CPAP 6 cmH₂O)] 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_CPAP. Nasal CPAP modified sucking-swallowing-breathing coordination, whereas the efficiency of oral feeding decreased under HFNC_CPAP. 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.NEW & NOTEWORTHY 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.

Oral-feeding guidelines for preterm neonates in the NICU: a scoping review

OBJECTIVE

This scoping review describes the nature and evidence base of internationally available guidelines for the introduction of oral feeding for preterm infants in neonatal units.

STUDY DESIGN

Thirty-nine current infant oral feeding introduction guidelines were obtained, and their recommendations contrasted with available scientific literature.

RESULT

Documents were primarily from the USA, UK, Canada, and Australia, from hospitals, regional health authorities, and journal articles. Specifics of nonnutritive sucking, gestational age at first feed, exclusions to oral feeding, suggested interventions, and the definition of full oral feeding varied between documents. There was variable use of scientific evidence to back up recommendations.

CONCLUSION

Guidelines for oral feeding, whether written by clinicians or researchers, vary greatly in their recommendations and details of interventions. Areas more widely researched were more commonly discussed. Recommendations varied more when evidence was not available or weak. Guideline developers need to synthesize evidence and local variability to create appropriate guidelines.

Characterization of esophageal motility and esophagogastric junction in preterm infants with bronchopulmonary dysplasia

BACKGROUND

To characterize esophageal motility and function of the esophagogastric junction (EGJ) in preterm infants with bronchopulmonary dysplasia (BPD).

METHODS

High-resolution manometry with impedance was used to investigate esophageal motility and EGJ function in 28 tube-fed preterm infants with BPD. Patients with BPD were studied at term age during oral feeding. Thirteen healthy term-aged infants were included as controls. Esophageal analysis derived objective measures to evaluate esophageal contractile vigor, bolus distension pressure, EGJ relaxation, and EGJ barrier function (in rest and during respiration). In addition, we investigated the effect of BPD severity on these measures.

KEY RESULTS

A total of 140 nutritive swallows were analyzed (BPD, n = 92; controls, n = 48). Normal esophageal peristaltic wave patterns were observed in all infants. BPD patients had higher distal contractile esophageal strength compared with controls (Kruskal-Wallis (KW) P = .048), and their deglutitive EGJ relaxation was comparable to controls. Severe BPD patients showed higher bolus distension pressures, higher EGJ resting pressures, and increased EGJ contractile integrals compared with mild BPD patients (Mann-Whitney U P = .009, KW P = .012 and KW P = .028, respectively).

CONCLUSIONS AND INFERENCES

Preterm infants with BPD consistently present with normal peristaltic esophageal patterns following nutritive liquid swallows. The EGJ barrier tone and relaxation pressure appeared normal. In general, infants with BPD do not have altered esophageal motor function. There is however evidence for increased flow resistance at the EGJ in severe BPD patients possibly related to an increased contractility of the diaphragm.

Physiological Basis of Neonatal Aerodigestive Difficulties in Chronic Lung Disease

In the United States, preterm birth rates have steadily increased since 2014. Despite the recent advances in neonatal-perinatal care, more than 40% of very low-birth-weight infants develop chronic lung disease (CLD) and almost 25% have feeding difficulties resulting in delayed achievement of full oral feeds and longer hospital stay. Establishment of full oral feeds, a major challenge for preterm infants, becomes magnified among those on respiratory support and/or with CLD. The strategies to minimize aerodigestive disorders include supporting nonnutritive sucking, developing infant-directed feeding protocols, sensory oromotor stimulation, and early introduction of oral feeds.

The effects of oral feeding while on nasal continuous positive airway pressure (NCPAP) in preterm infants

OBJECTIVE

To determine whether delaying oral feeding until coming off NCPAP will alter feeding and respiratory-related morbidities in preterm infants.

DESIGN

In this retrospective pre-post analysis, outcomes were compared in two preterm infant groups (≤32 weeks gestation). Infants in Group 1 were orally fed while on NCPAP, while infants in Group 2 were only allowed oral feedings after ceasing NCPAP.

RESULTS

Although infants in Group 2 started feeds at a later postmenstrual age (PMA), they reached full oral feeding at a similar PMA compared with Group 1. Interestingly, there was a positive correlation between the duration of oral feeding while on NCPAP and the time spent on respiratory support in Group 1.

CONCLUSIONS

Delayed oral feeding until ceasing NCPAP did not contribute to feeding-related morbidities. We recommend caution when initiating oral feedings in preterm infants on NCPAP without evaluating the safety of the infants and their readiness for oral feedings.

Clinical characteristics of premature infants who orally feed on continuous positive airway pressure

BACKGROUND

Between 32 and 34 weeks postconceptional age (PCA), premature infants typically achieve neuromuscular maturation to initiate the coordination of a nutritive suck triad. Many premature infants also require intubation, which has been associated with dysphagia in adults and infants. At our institution, despite these factors, some infants have been noted to tolerate oral feeds while on continuous positive airway pressure (CPAP).

AIMS

Compare the clinical characteristics and duration of intubation in infants that initiate oral feedings on CPAP to infants that did not begin oral feeding on CPAP.

STUDY DESIGN

Retrospective case control study.

SUBJECTS

Infants with gestational age < 32 weeks who required CPAP at 32 weeks PCA.

OUTCOME MEASURES

Oral feeding was defined as any oral feed ≥5 ml. Duration of intubation was defined as the number of intubated days prior to 32 weeks PCA.

RESULTS

Of the 243 infants on CPAP at 32 weeks PCA, 31% (n = 76) began oral feeding on CPAP. Infants who initiated oral feeding on CPAP were of younger gestational age at birth (median 26 versus 27 weeks, p < 0.001) and remained intubated for longer (median 10.5 versus 2 days, p < 0.001).

CONCLUSIONS

Infants who began oral feeding on CPAP had lower gestational age and longer duration of intubation than infants who started oral feeding off CPAP.

Impact of SIMPLE Feeding Quality Improvement Strategies on Aerodigestive Milestones and Feeding Outcomes in BPD Infants

BACKGROUND AND OBJECTIVES

Delays with enteral and oral feeding milestones among premature infants with bronchopulmonary dysplasia (BPD) can be due to provider variation or infant-dependent factors. Our objectives with this study were to compare aerodigestive milestones and length of stay in BPD infants after implementing a quality improvement program to improve feeding outcomes.

METHODS

Using the Institute for Healthcare Improvement model for quality improvement, we implemented the simplified, individualized, milestone-targeted, pragmatic, longitudinal, and educational (SIMPLE) feeding strategy to enhance feeding and aerodigestive milestones among BPD infants. The key interventions addressed were as follows: (1) enteral feed initiation and advancement protocol; (2) oral feeding progression guidelines, optimization of respiratory support, feeding readiness scores, nonnutritive breastfeeding, and cue-based feeding; (3) active multidisciplinary collaboration; and (4) family-centered care. Comparisons were made between baseline (January 2009 to March 2010) and SIMPLE feeding strategy (May 2010 to December 2013) groups. Both groups included infants between 23 0/7 and 32 6/7 weeks' birth gestation, and ≤34 weeks' postmenstrual age at admission and discharge.

RESULTS

The baseline group and SIMPLE feeding group included 92 patients and 187 patients, respectively. Full enteral feeding, first oral feeding, full oral feeding, and length of stay milestones were (all P < .05) achieved sooner in the SIMPLE feeding group. Although the overall prevalence of BPD in the 2 groups is similar, the incidence of moderate BPD has decreased (P < .05) and severe BPD has increased (P < .05) in the SIMPLE feeding group.

CONCLUSIONS

SIMPLE feeding strategy advances postnatal maturation and acquisition of feeding milestones irrespective of the severity of BPD and impacts the length of stay, thereby lowering resource use.

Oral feeding practices and discharge timing for moderately preterm infants

BACKGROUND

Oral feeding skills of moderately preterm infants are not mature at birth.

AIMS

To establish the relationship between postmenstrual age at introduction of first oral feeding and attainment of full oral feeding and hospital discharge for moderately preterm infants.

STUDY DESIGN

Multicenter retrospective analysis of a prospective cohort of moderately preterm infants admitted to a Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network hospital.

SUBJECTS

6146 infants born at 29-33 weeks' gestation from January 2012 to November 2013.

OUTCOME MEASURES

Postmenstrual age at full oral feeding and at hospital discharge.

RESULTS

The median postmenstrual age at first oral feeding was 33.9 weeks (interquartile range 33.1-34.3). For each week earlier at first oral feeding, full oral feeding occurred 4.5 days earlier (p < 0.0001) and hospital stay was shortened by 3.4 days (p < 0.0001). Higher birth weight (p < 0.0001) and black maternal race (p = 0.0001) were associated with younger postmenstrual age at full oral feeding and at discharge.

CONCLUSION

Moderately preterm infants with earlier introduction of oral feeding achieved earlier full oral feeding and hospital discharge.

Reflex cardiorespiratory events from esophageal origin are heightened by preterm birth

The involvement of gastroesophageal refluxes in cardiorespiratory events of preterm infants remains controversial. While a few studies in full-term newborn animals have shown that stimulation of esophageal receptors leads to cardiorespiratory reflexes, the latter remain largely unknown, especially after premature birth. The present study aimed to 1) characterize the cardiorespiratory reflexes originating from esophageal receptors in newborn lambs and 2) test the hypotheses that preterm birth enhances reflex cardiorespiratory inhibition and that C-fibers are involved in these reflexes. Eight full-term lambs and 10 lambs born 14 days prematurely were studied. Following surgical instrumentation, a 6-h polysomnography was performed without sedation to record electrocardiogram, respiratory movements, arterial pressure, laryngeal constrictor muscle activity, state of alertness, and hemoglobin oxygen saturation. Five esophageal stimulations of the upper and/or lower esophagus, including rapid balloon inflation and/or HCl injection, were performed in random order. A second recording was performed in full-term lambs 24 h later, after C-fiber blockade by capsaicin. Results confirmed that esophageal stimulations induced inhibitory cardiorespiratory reflexes combined with protective mechanisms, including laryngeal closure, swallowing, coughing, increased arterial pressure, and arousal. Preterm birth heightened cardiorespiratory inhibition. The strongest cardiorespiratory inhibition was observed following simultaneous stimulation of the lower and upper esophagus. Finally, cardiorespiratory inhibition was decreased after C-fiber blockade. In conclusion, esophageal stimulation induces inhibitory cardiorespiratory reflexes, which are partly mediated by C-fibers and more pronounced in preterm lambs. Clinical relevance of these findings requires further studies, especially in conditions associated with increased cardiorespiratory events, e.g., neonatal infection.NEW & NOTEWORTHY Preterm birth heightens the cardiorespiratory events triggered by esophageal stimulation. The most extensive cardiorespiratory events are induced by simultaneous stimulation of the proximal and distal esophagus.

Effects of Nasal Continuous Positive Airway Pressure and High-Flow Nasal Cannula on Sucking, Swallowing, and Breathing during Bottle-Feeding in Lambs

The use of prolonged respiratory support under the form of high-flow nasal cannula (HFNC) or nasal continuous positive airway pressure (nCPAP) is frequent in newborn infants. Introduction of oral feeding under such nasal respiratory support is, however, highly controversial among neonatologists, due to the fear that it could disrupt sucking, swallowing, and breathing coordination and in turn induce cardiorespiratory events. The recent observation of tracheal aspirations during bottle-feeding in preterm infants under nCPAP justifies the use of animal models to perform more comprehensive physiological studies on the subject, in order to gain further insights for clinical studies. The objective of this study was to assess and compare the impact of HFNC and nCPAP on bottle-feeding in newborn lambs, in terms of bottle-feeding efficiency and safety as well as sucking-swallowing-breathing coordination. Eight full-term lambs were instrumented to record sucking, swallowing, and respiration as well as electrocardiogram and oxygenation. Lambs were bottle-fed in a standardized manner during three randomly ordered conditions, namely nCPAP 6 cmH₂O, HFNC 7 L/min, and no respiratory support. Results revealed that nCPAP decreased feeding duration [25 vs. 31 s (control) vs. 57 s (HFNC), p = 0.03] and increased the rate of milk transfer [2.4 vs. 1.9 mL/s (control) vs.1.1 mL/s (HFNC), p = 0.03]. No other indices of bottle-feeding safety or sucking-swallowing-breathing coordination were significantly altered by HFNC or nCPAP. In conclusion, our results obtained in full-term newborn lambs suggest that: (i) nCPAP 6 cmH₂O, but not HFNC 7 L/min, increases bottle-feeding efficiency; (ii) bottle-feeding is safe under nCPAP 6 cmH₂O and HFNC 7 L/min, with no significant alteration in sucking-swallowing-breathing coordination. The present informative and reassuring data in full-term healthy lambs must be complemented by similar studies in preterm lambs, including mild-to-moderate respiratory distress alleviated by respiratory support in order to mimic preterm infants with bronchopulmonary dysplasia and pave the way for clinical studies.