Mediational models of maternal stress in neonatal intensive care units.

BACKGROUND: Maternal stress in neonatal intensive care units (NICUs) is well acknowledged. However, there is currently no well-defined support at how to best assist mothers during their infants' hospitalization. Not only must they confront at the same time their infant's fragility, but also their own personal trials. In this exploratory study, we examined whether the Multiple-Stressor mediational modeling approach commonly used in Ecology could be used to better assist these parents. This approach calls attention to the overall impact that multiple stressors can have on an organism, i.e., not only in regard to their individual effects, but just as importantly, through their interactions with each other, be they positive or negative. It is hypothesized that the use of such mediational modeling could improve our understanding of the overall impact that multiple stressors can have on NICU mothers. METHODS: At 2 weeks postpartum, 30 mothers with infants born between 24 and 29 weeks gestation responded to the following self-reported psychological outcome measures: Affect Intensity Measure (AIM); Crowne-Marlowe Social Desirability Scale (CM); Edinburgh Postnatal Depression Scale (EDPS); Brief Symptom Inventory-Anxiety (BSI-Anx); Parental Stress Scale: NICU (PSS:NICU); Multidimensional Scale of Perceived Social Support (MSPSS); and Coping Inventory for Stressful Situations (CISS). The "Best Subsets Regression" analysis (www.minitab.com) was used to identify the four interactive maternal outcome measures that best correlated with the mediational stress models of interest, namely, Depression, Anxiety, parental NICU stress, Perceived Social Support, and Coping skills. RESULTS: The following mediational models of maternal stress outcomes during their infant's NICU hospitalization were identified: depression, anxiety, stress of the sights and sounds in the NICU, "the looks of my baby", my "inability" to be a parent, perceived social support, and coping skills. CONCLUSIONS: It is advanced that the use of the Multiple-Stressor approach, with its ability to identify factors associated with particular stressors, can offer psychosocial providers a more tangible understanding of the maternal key elements at the source of maternal stress in NICUs. It is expected that to ease the stressful experiences these mothers encounter, such approach will facilitate the development of more effective interventions to assist these parents' challenges than currently available.

Management of Oral Feeding Challenges in Neonatal Intensive Care Units (NICUs): A National Survey in China.

Objectives: To investigate the current practices of oral feeding difficulties facing high-risk infants in Chinese NICUs. Methods: A questionnaire to survey infant oral feeding practices was distributed to 100 level II and III Chinese neonatal intensive care units (NICUs). Results: Responses were obtained from 88 NICUs. No Units had any structured guidelines regarding the management of infant oral feeding as they transitioned from tube to independent oral feeding. In 54 (61.4%) NICUs, nurses and physicians made shared decisions on when oral feeding were to be initiated. Fifty-four (61.4%) and 22 (25.0%) NICUs used postmenstrual age (PMA) or weight at PMA as a criterion for initiating oral feedings, respectively. The top three criteria to determine introduction of oral feeding were severity of disease, presence of sucking reflex, and trial feeding success. Adverse events were used by 78 Units as indices of oral feeding difficulty. Twenty (22.7%) and 25 (28.4%) Units had access to occupational therapists or nurses who provided oral motor interventions during feeding, i.e., oral support (chin and cheek support, aid to deglutition), non-nutritive sucking with pacifier, and oral stimulation. Conclusions: The management of oral feeding issues in NICUs vary widely in China in relation to the assessment of readiness to oral feeding, daily oral feeding practices and interventions used by staff. It is proposed that an educational program focused on the physiology of infant oral feeding, available evidence-based tools and interventions would assist NICU caregivers develop structured guidelines to improve infants' safe and efficient attainment of independent oral feeding.

To Individualize the Management Care of High-Risk Infants With Oral Feeding Challenges: What Do We Know? What Can We Do?

The increase in preterm infants' survival over the last 30 years has shed light over their inability to feed by mouth safely and efficiently. With adverse events such as increased risks for oxygen desaturation, bradycardia, penetration/aspiration, infants' hospitalization in neonatal intensive care units (NICUs) are understandably prolonged. Unfortunately, this leads to delayed mother-infant reunion, maternal stress, breastfeeding obstacles, and increased medical costs. Such impediments have stimulated clinicians and researchers to better understand the underlying causes and develop evidence-based solutions to assist these infants. However, it is notable that the research-to-practice translation of this knowledge has been limited as there are still no validated guidelines or protocols as how to best diagnose and care for these infants. This report revisits the immature physiologic functions at the root of these infants' oral feeding difficulties, the current practices, and the recent availability of evidence-based efficacious tools and interventions. Taking advantage of the latter, it presents a renewed perspective of how management strategies can be tailored to the specific needs of individual patients.

Breastfeeding Challenges and the Preterm Mother-Infant Dyad: A Conceptual Model.

Breastfeeding is an experience that only a mother and her infant(s) can share. Infants who can feed from the breast receive not only the best nutrition but also, due to the close physical contact between mother and child, it is the optimal nurturance they can receive from their mother. When breastfeeding is trouble free, maternal well-being is uniquely heightened. However, breastfeeding remains a challenge for many mother-infant dyads and more so for those whose infants are born prematurely. This article introduces a conceptual model of the breastfeeding challenges facing preterm mother-infant dyads. It distinguishes between a maternal caregiving and an infant growth/development components. Within the maternal component, two primary elements are considered, that is, maternal behavioral and nutritional care. The two primary elements within the infant component include infant non-nutritional and nutritional growth/development. It is proposed that an improved understanding of the factors associated with these four elements and how they interplay with each other within individual dyads will facilitate the identification of the breastfeeding challenges facing these mother-infant entities. Due to the intimate relationships existing between a mother and her infant(s), it is further advanced that breastfeeding studies would be optimized if mother-infant pairs are studied as one entity rather than mother and infant separately. It is proposed that this conceptual model will assist health professionals develop personalized breastfeeding management plans for individual preterm mother-infant dyads, while furthering the development of evidence-based interventions to optimize their breastfeeding experiences.

The Development of the Mother-Infant Mutualistic Screening Scale.

BACKGROUND: The integrity of a mother-infant dyad is essential for the proper development of maternal behavior and infant growth/ development. At present, there is a lack of objective approaches to monitor mother-infant behavioral exchanges. OBJECTIVES: This is an exploratory prospective study designed to evaluate the Mother-Infant Mutualistic Screening Scale (MIMSS), a novel observational tool focused on monitoring the mutual/ reciprocal sensitivity and responsiveness that mother and infant express toward one another's behaviors/ actions during the obligatory setting of daily meal times. METHODS: Mother-infant interactions were assessed from videotaped feeding sessions conducted under recurrent naturalistic observations. Data were collected from 27 mother-preterm infant singleton dyads at 6 and 12 month corrected age (CA). Four levels of MIMSS are defined: Level I - both mother and infant are not responsive (NR) to one another's actions; Level II - mother is not responsive (NR) to infant, but infant is responsive (R) to mother; Level III - mother is responsive (R) to infant, but infant is not responsive (NR) to mother; Level IV - both mother and infant are responsive (R) to one another. RESULTS: Inter- and intra-rater reliability between two raters was 93% and ≥ 85%, respectively. At 6 and 12 month CA, 78% and 81% of the dyads were at a MIMSS Level IV, respectively. A change in mother-infant reciprocal behavioral responses or MIMSS levels was observed in 9 of the dyads between these two ages. No association was observed between MIMSS levels and infant growth/ development as monitored by percentile Weight, Length, and Weight by Length at both corrected ages. CONCLUSIONS: The MIMSS is easy to use with high inter- and intra-rater reliabilities. With the ability to differentiate between mother and infant reciprocal behavioral responses toward one another's actions, MIMSS can help health professionals assess the quality of mother-infant interactions and identify the partner(s) who may benefit from individualized assistance. Although MIMSS uses mealtime as a recurrent setting, it offers a conceptual frame work for evaluating co-regulatory processes under different contexts.

Development of infant oral feeding skills: what do we know?

The hospital discharge of premature infants in neonatal intensive care units is often delayed due to their inability to feed by mouth safely and competently. With immature physiologic functions, infants born prematurely cannot be expected to readily feed by mouth at the equivalent age of a third trimester of gestation as the majority of their term counterparts do. Consequently, it is crucial that health care professionals gain an adequate knowledge of the development of preterm infants' oral feeding skills so as to optimize their safety and competency as they transition to oral feeding. With a greater sensitivity toward their immature skills, we can offer these infants a safer and smoother transition to independent oral feeding than is currently observed. This review article is an overview of the evidence-based research undertaken over the past 2 decades on the development of very-low-birth-weight infants' oral feeding skills. The description of the different functional levels where these infants can encounter hurdles may assist caregivers in identifying a potential cause or causes for their individual patients' oral feeding difficulties.

Development of Suck and Swallow Mechanisms in Infants.

Preterm infants' hospital discharge is often delayed due to their inability to feed by mouth safely and competently. No evidence-based supported guidelines are currently available for health-care professionals caring for these infants. Available interventions advocating benefits are not readily acknowledged for lack of rigorous documentation inasmuch as any improvements may ensue from infants' normal maturation. Through research, a growing understanding of the development of nutritive sucking skills has emerged, shedding light on how and why infants may encounter oral feeding difficulties due to the immaturity of specific physiologic functions. Unfortunately, this knowledge has yet to be translated to the clinical practice to improve the diagnoses of oral feeding problems through the development of relevant assessment tools and to enhance infants' oral feeding skills through the development of efficacious preventive and therapeutic interventions. This review focuses on the maturation of the various physiologic functions implicated in the transport of a bolus from the oral cavity to the stomach. Although infants' readiness for oral feeding is deemed attained when suck, swallow, and respiration are coordinated, we do not have a clear definition of what coordination implies. We have learned that each of these functions encompasses a number of elements that mature at different times and rates. Consequently, it would appear that the proper functioning of sucking, the swallow processing, and respiration need to occur at two levels: first, the elements within each function must reach an appropriate functional maturation that can work in synchrony with each other to generate an appropriate suck, swallow process, and respiration; and second, the elements of all these distinct functions, in turn, must be able to do the same at an integrative level to ensure the safe and efficient transport of a bolus from the mouth to the stomach.

Oral Feeding Assessment Predicts Length of Hospital Stay in Late Preterm Infants.

BACKGROUND: When compared with term infants, late preterm (LP) infants have greater morbidity and mortality, longer hospital stay, and greater rate of hospital readmission. Oral feeding difficulty is one of the prominent reasons for delayed discharge in LP infants. OBJECTIVE: To identify the maturity levels of LP infants' oral feeding skills (OFS) at the time of their first oral feeding and to determine the relationship between OFS maturity levels and length of hospital stay. METHODS: OFS was assessed in 48 LP infants born between 340/7 and 356/7 weeks gestational age at the time of their first oral feeding within 24 h of birth. The intake at 5 minutes, at completion of the feeding, and the duration of feeding a 15 mL prescribed volume of milk were tabulated. Proficiency expressed as percent mL consumed in the first 5 min/15 mL prescribed and rate of milk transfer over the entire feeding (mL/min) were recorded. OFS were assessed using a novel 4-level scale defined by the combined proficiency and rate of milk transfer. RESULTS: When compared with their 35-week counterparts, infants born at 34 weeks gestation had poorer OFS profiles (p = 0.035) and longer hospital stay (p < 0.001). Additionally, further analyses demonstrated that, independently, LOS was associated negatively with both GA and OFS. CONCLUSION: Assessment of OFS levels in LP infants at their first oral feeding can help identify infants at risk of oral feeding issues that may delay hospital discharge. For those infants, we speculate that provision of evidence-based efficacious interventions that improve OFS may shorten hospital stay and decrease hospital re-admissions.

Is there an advantage for preterm infants to feed orally in an upright or sidelying position?

Over the last decade, nursing staff and feeding therapists have promoted the upright and sidelying bottle feeding positions as 'optimal' for preterm infants. To verify such benefits, very low birth weight infants were randomized to being fed in the customary semi-reclined (control), upright, or side-lying position. The primary outcome was days from start to independent oral feeding. Secondary outcomes included infants' oral feeding skill levels monitored when taking 1,2, 3-5, and 6-8 oral feedings per day. Infants fed in the upright and sidelying groups attained independent oral feeding within the same number of days as control counterparts. There was no difference in the maturation of their oral feeding skills.

Oral and nonoral sensorimotor interventions facilitate suck-swallow-respiration functions and their coordination in preterm infants.

BACKGROUND: Preterm infants are at high risk of encountering oral feeding difficulties. Early sensorimotor interventions may improve oral feeding skills in preterm infants. AIM: To further explore the effects of an oral (O), tactile/kinesthetic (T/K), and combined (O+T/K) sensorimotor intervention on preterm infants' nutritive sucking, swallowing and their coordination with respiration. STUDY DESIGN: Seventy-five infants (29 [0.3, standard error of mean, SEM] weeks gestation, 49 males/26 females) were randomly assigned to an O group involving sensorimotor input to the oral structures; a T/K group involving sensorimotor input to the trunk and limbs; a combined (O+T/K) group; and a control group. OUTCOME MEASURES: Stage of sucking, suction and expression amplitudes (mmHg), suck-swallow ratio, stability of suck-swallow interval, and swallow-respiration patterns. RESULTS: The O group had significantly more advanced sucking stages, and greater suction and expression amplitudes than controls [p≤0.035, effect size (ES) >0.6]. The suck-swallow ratio and stability of suck-swallow intervals did not significantly differ among groups (p≥0.181, ES≤0.3). The three interventions led to fewer swallows bracketed by prolonged respiratory pauses compared to controls (pause-swallow-pause, p≤0.044, ES≥0.7). The T/K and combined (O+T/K) groups had greater occurrence of swallows bracketed by expiration than the control and O groups (expiration-swallow-expiration, p≤0.039, ES≥0.3). CONCLUSION: The O intervention enhanced specific components of nutritive sucking. All three interventions resulted in improved swallow-respiration coordination. Sensorimotor interventions have distributed beneficial effects that go beyond the specific target of input.

Oral and non-oral sensorimotor interventions enhance oral feeding performance in preterm infants.

AIM: The aim of this study was to determine whether oral, tactile/kinaesthetic (T/K), or combined (oral+T/K) interventions enhance oral feeding performance and whether combined interventions have an additive/synergistic effect. METHOD: Seventy-five preterm infants (mean gestational age 29 wk; standard error of the mean [SEM] 0.3 wk; mean birthweight 1340.3g; SEM 52.5 g; 49 males and 26 females) were randomly assigned to one of three intervention groups or a control group. The oral group received sensorimotor input to the oral structures, the T/K group received sensorimotor input to the trunk and limbs, and the combined group received both. The outcomes were time from introduction of nipple feeding to independent oral feeding (d), proficiency (intake in the first 5 min, %), volume transfer (%), rate of transfer (mL/min), volume loss (%), and length of hospital stay (d). RESULTS: Infants in the three intervention groups achieved independent oral feeding 9-10 days earlier than those in the control group (p<0.001; effect size 1.9-2.1). Proficiency (p ≤ 0.002; effect size 0.7-1.4) at the time of one to two and three to five oral feedings per day, volume transfer (p ≤ 0.001; effect size 0.8-1.1) at one to two, three to five, and six to eight oral feedings per day, and overall rate of transfer (p ≤ 0.018; effect size 0.8-1.1) were greater, and overall volume losses were less (p ≤ 0.007; effect size 0.9-1.1), than in the control group (p ≤ 0.042). The combined group attained independent oral feeding at a significantly younger postmenstrual age than controls (p=0.020) and had clinically greater proficiency than the T/K group (p=0.020; effect size 0.7) and oral group (p=0.109; effect size 0.5). Length of hospital stay was not significantly different between groups (p=0.792; effect size 0.02-0.3). INTERPRETATION: Oral and T/K interventions accelerated the transition from introduction to independent oral feeding and enhanced oral feeding skills. T/K has beneficial effects beyond the specific targeted system. The combined sensorimotor intervention led to an additive/synergistic effect for proficiency, further benefiting this population.

A controlled-flow vacuum-free bottle system enhances preterm infants' nutritive sucking skills.

We have shown that a controlled-flow vacuum-free bottle system (CFVFB) vs. a standard bottle (SB) facilitates overall transfer and rate of milk transfer, and shortens oral feeding duration in very-low-birth-weight (VLBW) infants. We aimed to understand the basis by which this occurs. Thirty infants (19 males; 27 +/- 1 weeks gestation) were randomized to a CFVFB or SB. Outcomes monitored at 1-2 and 6-8 oral feedings/day when infants were around 34 and 36 weeks postmenstrual age, respectively, included: overall transfer (% volume taken/volume prescribed), rate of milk transfer (ml/min), sucking stage, frequency of suction (#S/s) and expression (#E/s), suction amplitude (mmHg), and sucking burst duration (s). At both periods we confirmed that infants using a CFVFB vs. SB demonstrated greater overall transfer and rate of milk transfer, along with more mature sucking stages. Suction and expression frequencies were decreased with CFVFB vs. SB at 1-2 oral feeding/day; only that of suction was reduced at 6-8 oral feedings/day. No group differences in suction amplitude and burst duration were observed. We speculate that oral feeding performance improves without significant change in sucking effort with a CFVFB vs. SB. In addition, we have shown that VLBW infants can tolerate faster milk flow than currently presumed. Finally, the use of a CFVFB may reduce energy expenditure as it enhances feeding performance without increasing sucking effort.

Does the choice of bottle nipple affect the oral feeding performance of very-low-birthweight (VLBW) infants?

BACKGROUND: There is a continuous debate regarding the best bottle nipple to be used to enhance the bottle-feeding performance of a preterm infant. AIM: To verify that feeding performance can be improved by using the bottle nipple with the physical characteristics that enhance infants' sucking skills. METHODS: Ten "healthy" VLBW infants (941+/-273 g) were recruited. Feeding performance was monitored at two time periods, when taking 1-2 and 6-8 oral feedings/d. At each time and within 24 h, performance was monitored using three different bottle nipples offered in a randomized order. Rate of milk transfer (ml/min) was the primary outcome measure. The sucking skills monitored comprised stage of sucking, suction amplitude, and duration of the generated negative intraoral suction pressure. RESULTS: At both times, infants demonstrated a similar rate of milk transfer among all three nipples. However, the stage of sucking, suction amplitude, and duration of the generated suction were significantly different between nipples at 1-2, but not 6-8 oral feedings/d. CONCLUSION: We did not identify a particular bottle nipple that enhanced bottle feeding in healthy VLBW infants. Based on the notion that afferent sensory feedback may allow infants to adapt to changing conditions, we speculate that infants can modify their sucking skills in order to maintain a rate of milk transfer that is appropriate with the level of suck-swallow-breathe coordination achieved at a particular time. Therefore, it is proposed that caretakers should be more concerned over monitoring the coordination of suck-swallow-breathe than over the selection of bottle nipples.

Randomized trial of donor human milk versus preterm formula as substitutes for mothers' own milk in the feeding of extremely premature infants.

OBJECTIVE: Compared with preterm formula (PF), mother's milk (MM) is associated with lower rates of late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) among premature infants. Because not all mothers of premature infants produce sufficient milk to supply their infants throughout hospitalization, we reasoned that pasteurized donor human milk (DM) would be a suitable alternative. METHODS: Extremely premature infants (<30 weeks of gestation) whose mothers intended to breastfeed were assigned randomly to receive either pasteurized DM or PF if the supply of their own MM became insufficient during the study (birth to 90 days of age or hospital discharge). Infection-related events (LOS, NEC, meningitis, presumed sepsis, or urinary tract infection) that occurred after the attainment of a milk intake of 50 mL/kg, dietary intake, growth, skin-to-skin contact, and duration of hospital stay were compared. The primary analysis compared groups DM and PF on an intent-to-treat basis. If no differences were noted, then these groups were combined and compared with the reference group, group MM. If differences were noted, then the subsequent analyses compared each group with group MM. RESULTS: Of 243 infants, 70 (29%) received only MM; group DM included 81 infants and group PF included 92 infants. Because of poor weight gain, 17 infants (21%), all in group DM, were switched to PF. There were no differences in birth weight, gestational age, multiple births, and age at attainment of feeding of 50 mL/kg among groups. There were no differences between group DM and group PF in LOS and/or NEC, other infection-related events, hospital stay, or number of deaths. Group DM received a greater intake of milk and more nutritional supplements but had a slower rate of weight gain, compared with group PF. Compared with groups DM and PF, group MM had fewer episodes of LOS and/or NEC and total infection-related events and a shorter duration of hospital stay. Group MM also had fewer Gram-negative organisms isolated from blood cultures than did the other groups. CONCLUSIONS: In this randomized, blinded trial of feeding of extremely premature infants, we found that, as a substitute for MM, DM offered little observed short-term advantage over PF for feeding extremely premature infants. Advantages to an exclusive diet of MM were observed in terms of fewer infection-related events and shorter hospital stays.

Early introduction of oral feeding in preterm infants.

OBJECTIVE: To determine whether transition from tube to all oral feeding can be accelerated by the early introduction of oral feeding in preterm infants. It is hypothesized that this shortened transition time will lead to earlier attainment of all oral feeding. DESIGN: Twenty-nine infants (<30 weeks' gestation) were randomized to an intervention or control group. The intervention group (n = 13) was initiated to oral feeding 48 hours after achieving full tube feeding (120 kcal/kg/d), and the feeding progression followed a structured protocol. The oral feeding management of the control infants (n = 16) was left to the discretion of their attending physicians. Oral feeding progress was monitored for achievement of selected feeding milestones: achievement of first and all successful oral feedings. Feeding performance was assessed by overall transfer (percent volume transferred during a feeding/total volume offered) and rate of milk transfer (mL/min), which were measured from introduction of oral feeding to first successful oral feeding. RESULTS: Infants in the experimental group, when compared with their control counterparts, were introduced to oral feeding significantly earlier (31.1 +/- 1.3 vs 33.7 +/- 0.9 weeks' postmenstrual age, respectively) and attained all oral feeding significantly earlier as well (34.5 +/- 1.6 vs 36.0 +/- 1.5 weeks' postmenstrual age, respectively). The transition time from full tube feeding to all oral feeding was 26.8 +/- 12.3 days for the experimental group and 38.4 +/- 14.0 days for the control group. Both groups of infants demonstrated similar increase in overall transfer and rate of milk transfer from introduction of oral feeding until achievement of first successful oral feeding. CONCLUSIONS: Early introduction of oral feeding accelerates the transition time from tube to all oral feeding. This not only allows earlier attainment of all oral feeding, but it also provides practice opportunities that enhance the oral motor skills necessary for safe and successful feeding.

Oral stimulation accelerates the transition from tube to oral feeding in preterm infants.

OBJECTIVE: To assess whether an oral stimulation program, before the introduction of oral feeding, enhances the oral feeding performance of preterm infants born between 26 and 29 weeks' gestational age. STUDY DESIGN: Preterm infants (n = 32) were randomized into an experimental and control group. Infants in the experimental group received an oral stimulation program consisting of stimulation of the oral structures for 15 minutes. Infants in the control group received a sham stimulation program. Both were administered once per day for 10 consecutive days, 48 hours after discontinuation of nasal continuous positive air pressure. RESULTS: Independent oral feeding was attained significantly earlier in the experimental group than the control group, 11 +/- 4 days (mean +/- SD) versus 18 +/- 7 days, respectively (P =.005). Overall intake and rate of milk transfer were significantly greater over time in the experimental group than the control group (P =.0002 and.046, respectively). There was no difference in length of hospital stay between the 2 groups. CONCLUSION: An early oral stimulation program accelerates the transition to full oral feedings in preterm infants. This was associated with greater overall intake and rate of milk transfer observed in the experimental group when compared with the control group.