Sixty premature infants admitted to the NICU of a large referral hospital in Tehran, Iran, from June 2018 until January 2019 participated in this quasi-experimental study. In order to prevent information spill-over after training in BCBF, a phase lag design was adopted. Phase 1 served as the control phase and Phase 2 as the experimental or intervention phase.
The study hospital’s NICU has 23 level III intensive care beds and a staff of 39 full-time nurses. Infant inclusion criteria were as follows: Gestational age, 28 to 36 weeks based on medical records; physiologically stable by onset of study; lack of congenital malformations; discontinuation of all parenteral fluids and intravenous lines; and cared for in an incubator. Exclusion criteria included: Intraventricular hemorrhage grade III and IV as established by independent ultrasound and/or MRI; necrotizing enterocolitis; Stage II and III bronchopulmonary dysplasia as based on independent X-ray review; sepsis; major medical illness in the mother, e.g. diabetes; lack of weight gain for three consecutive days; current treatment with mechanical ventilation, sedative medication and/or phototherapy. Background variables recorded included demographic and medical sample descriptors as well as various caregiver characteristics as follow: Gestational age at birth, birth weight, gender, Apgar score at one and five minutes, cause of hospitalization, duration of ventilation, and post conceptional age at start of oral feeding. Nurse caregiver characteristics included age, years of experience, full-time or part-time status, and prior successful completion of courses in breastfeeding and/or infant developmental care. Outcome variables collected during all work shifts included: Timing from onset of independent feedings, frequency of independent oral feeding events, frequency of gavage feeding events, and frequency of oxygen desaturation and of apnea events, all to discharge from the hospital. Additionally, in both groups daily weight-gain since study entry until 21 days thereafter was measured because the minimum duration of an infant’s participation in the study was 21 days. Feeding volumes and feeding methods including direct breastfeeding, cup feeding, dropper, syringe, and gavage feedings were recorded for descriptive purposes only. For both groups’ background and outcome variables were collected from each infant’s medical chart after the infant’s discharge from the NICU by the nurse, who cared for, and was familiar with the infant. All participating nurses in both groups were trained in chart review by the researcher.
After completion of the Phase 1 sample intake, an intervention training phase was instituted. First, the planned intervention of the behavioral cue-based feeding (BCBF) protocol was discussed, and collaboration and cooperation assurances were obtained from all neonatologists and their assistants, and from the NICU nurse manager and the educational supervisor of the nursery. Subsequent training consisted of two workshops for all staff (39 nurses and 5 physicians). The intervention was modelled on the cue-based behavioral oral feeding protocol as proposed by the University of Utah . Workshop content included the definition of cue-based feeding and reasons for its importance; the goals and benefits of this feeding method; training in the recognition of preterm infants’ behavioral cues as spelled out in the NIDCAP methodology, and specifically of behavioral cues associated with feeding, such as readiness to feed, signs of hunger, fatigue, and of satiation. Co-author HM. a certified NIDCAP Professional, supervised this training. To remind the nursing staff of the educational workshop contents, posters depicting/describing feeding based behavioral cues were created and made available throughout the intervention period. Infant cues included waking up, moaning, fussing, relaxed facial expression, eyes fully open, becoming upset, crying, bringing hands to the mouth, grasping, rooting, attempts to suck and/or successfully sucking on a pacifier or finger; modulated good tone, limp facial musculature, limp posture of arms, hands and legs of trunk, head droop, and color changes to pale or mottled, among others [17, 23]. After two weeks of BCBF training the intervention group infants were admitted to the study and the BCBF intervention began. The attending neonatologist recorded in the chart when the decision was made to discontinue the infants’ intravenous feedings. The intervention subsequently proceeded in three stages: In the first stage one oral feeding, based on the study infant’s behavioral cues, was offered every 12 hours; in the second stage two oral feedings, based on the study infant’s behavioral cues, were offered every 12 hours; and finally, in the third stage, all oral feedings were based on the study infant’s behavioral cues. Stages one and two each lasted for three days, and from the seventh day forward counted from initiation of the intervention, the infant received complete oral feedings. Once the infant, in addition to complete oral feedings, showed stable weight gain for 72 hours, he/she was discharged. In the first and second stages, a nurse trained in cue-based feeding fed the infant. In the third stage, the mothers of the Phase 2 study infants also received cue-based education and provided the feeding when they were present in the nursery. Clinical adaptations to the three stages were instituted when an infant failed to show any signs of wakefulness or hunger for up to four hours after the previous feeding; in such cases the infant was fed in accordance with the baby's clinical status (direct breastfeeding, feeding through a cup, a dropper, a syringe, or gavage) to prevent hypoglycemia. Transition from one stage to the next was subject to appropriate weight gain (at a minimum 10 g within 24 hours) and the continued absence of apnea, bradycardia and/or oxygen desaturation during feeding. Otherwise, until the infant achieved adequate weight gain, the infant remained at the same stage of feeding as before.
Infant weight in both groups was measured as a routine nursing care in the NICU by trained nurses at the beginning of each morning shift with the infant uncovered and undressed and by using the same digital scale (SEKA, made in China), which has an accuracy of 5 to 10 grams. To determine arterial oxygen saturation and the frequency of a 20 second apnea (accompanied by a bradycardia and or desaturation), Iranian manufactured cardiovascular monitors (SAADAT) were used.
Data were analyzed using the Statistical Package for the Social Sciences (SPSS), version 16. For the examination of group differences of continuous variables two-tailed T-tests and repeated measures Analysis of Variance (ANOVA) was used in order to check the weight gain to 21 days after meeting criterion for onset of the intervention in both groups. For categorical variables two-tailed Chi-Square tests were used. A two-tailed probability value (P) of <0.05 was accepted as statistically significant. In Phase 1, the control group infants (30) began their oral feeding every two or three hours according to the study nursery’s routine and physician’s order, dependent on post-conceptional age and nursery-protocol-determined volumes/24 hours. Attempts at breastfeeding were initiated by 34 weeks post-conceptional age.
The sample size in each group was estimated to be 30 infants in order to achieve an effect size of 0.5, 95% confidence interval with 80% power.