Biobehavioral Efficacy of the Semi-Elevated Side-Lying Position

The objective of the proposed research is to conduct a within-subject cross-over trial that will compare the efficacy of the two bottle-feeding positions on physiologic and behavioral responses of preterm infants prior to, during, and after feeding. As an exploratory aim, the investigators will also identify potential infant characteristics associated with the intervention response by evaluating infant sex, maturity level, and/or comorbidity. The two bottle-feeding positions will be the semi-elevated side-lying position (hereafter referred to as side-lying position) and the semi-elevated supine position (hereafter referred to as supine position), which is the traditional feeding position when preterm infants are bottle-fed. The investigators hypothesize that compared to the supine position, the side-lying position will be associated with greater physiologic stability in heart rate, respiratory rate, oxygen saturation, and/or autonomic nervous system regulation during and after feeding. The investigators also hypothesize that compared to the supine position, the side-lying position will be associated with more mature patterns of suck-breathe coordination and/or greater feeding skills.

In this arm, infants will be bottle-fed in the side-lying position first followed by the supine position.

In this arm, infants will be bottle-fed in the supine position first followed by the side-lying position.

Infants will be observed for two bottle feedings in a single day when they are receiving at least 30% and no more than 50% of feedings orally. In this arm, infants will be bottle-fed in the side-lying position first followed by the supine position. In the side-lying feeding position, the infant will be placed on the caregiver's lap with one ear and hip facing the ceiling at a 45 to 60 degree angle. In the supine feeding position, the infant will be placed facing the caregiver in a reclining position at a 45 to 60 degree angle. In both feeding positions, the infant's head, neck, and upper body will be supported by the caregiver to maintain a neutral straight alignment with the chin tilted down slightly without the neck being extended or in excessive flexion. The infant will also be loosely swaddled with a single blanket so their legs, shoulders, and elbows are supported in a flexed position but with the lower arms free to move.

Infants will be observed for two bottle feedings in a single day when they are receiving at least 30% and no more than 50% of feedings orally. In this arm, infants will be bottle-fed in the supine position first followed by the side-lying position. In the side-lying feeding position, the infant will be placed on the caregiver's lap with one ear and hip facing the ceiling at a 45 to 60 degree angle. In the supine feeding position, the infant will be placed facing the caregiver in a reclining position at a 45 to 60 degree angle. In both feeding positions, the infant's head, neck, and upper body will be supported by the caregiver to maintain a neutral straight alignment with the chin tilted down slightly without the neck being extended or in excessive flexion. The infant will also be loosely swaddled with a single blanket so their legs, shoulders, and elbows are supported in a flexed position but with the lower arms free to move.

HR will be measured for 30 minutes pre-feeding (baseline), feeding, and 30 minutes post-feeding (recovery).

RR will be measured for 30 minutes pre-feeding (baseline), feeding, and 30 minutes post-feeding (recovery).

SaO2 will be measured for 30 minutes pre-feeding (baseline), feeding, and 30 minutes post-feeding (recovery).

HRV will be measured for 30 minutes pre-feeding (baseline), feeding, and 30 minutes post-feeding (recovery).

SCOR will be measured for 30 minutes pre-feeding (baseline), feeding, and 30 minutes post-feeding (recovery).

Infant behavioral responses will be assessed by the behavioral observation of suck-breathe coordination patterns using Suck-Breath Coordination coding scheme.

Infant behavioral responses will be assessed by the behavioral observation of infant feeding skill using the Early Feeding Skills (EFS) assessment tool.

Overall severity illness score will be calculated using the Neonatal Medical Index (range of 1 [least severe] to 5 [most severe])

Severity of lung disease will be assessed using diagnostic criteria of bronchopulmonary dysplasia (none, mild, moderate, or severe)

Inclusion Criteria: Preterm infants who are born at ≤ 35 weeks of GA Exclusion Criteria: Congenital anomaly that may interfere with feeding (e.g., cleft palate or tracheoesophageal fistula) Grade IV intraventricular hemorrhage Ventilator-dependence beyond 60 days of life Inability to orally feed prior to discharge

A database will be established to store project data. This data will be free of identifiers that would permit linkages to individual research participants and variables that could lead to deductive disclosure of the identity of individual subjects. Presentations, abstracts, and manuscripts related to the work will also be centrally stored. Once the project is finished and all analyses are complete, it is our intention to make the study dataset available upon request.

Investigators wishing to use the data will submit a written request to the PI and provide a data use agreement with Boston College, stating that the data will be used for scientific purposes. The data and associated documentation will be available to users only under a data-sharing agreement that provides for: 1) a commitment to using the data only for research purposes and not to identify any individual participant; 2) a commitment to securing the data using appropriate computer technology; and 3) a commitment to destroying or returning the data after analyses are completed. There will be no cost for data sharing. Data will be provided to the investigator in an appropriate confidential electronic format.