Maternal-Infant Interaction and Autonomic Function in Healthy Infants and Infants With Transposition of the Great Arteries

Oral feeding dysfunction in post-operative infants with CHDs: a scoping review

Post-operative oral feeding difficulties in neonates and infants with CHD is common. While pre-operative oral feeding may be normal, oral feeding challenges manifest in the post-operative period without a clearly defined aetiology. The objective of this scoping review was to examine post-operative oral feeding in full-term neonates and infants with a CHD. Electronic databases query (1 January 1975-31 May 2021), hand-search of the reference lists of included studies, contact with experts, and review of relevant conferences were performed to identify quantitative studies evaluating post-operative oral feeding in full-term neonates and infants with a CHD. Associations with additional quantitative variables in these studies were also examined. Twenty-five studies met inclusion criteria. Eighty per cent were cohort studies that utilised retrospective chart review from a single institution. The primary variable of interest in all studies was oral feeding status upon discharge from neonatal hospitalisation. The most common risk factors evaluated with poor feeding at time of discharge were birth weight (36% of included studies), gestational age (44%), duration of post-operative intubation (48%), cardiac diagnosis (40%), and presence of genetic syndrome or chromosomal anomaly (36%). The most common health-related outcomes evaluated were length of hospital stay (40%) and length of ICU stay (16%). Only the health-related outcomes of length of hospital stay and length of ICU stay were consistently significantly associated with poor post-operative oral feeding across studies in this review. A clear aetiology of poor post-operative oral feeding remains unknown.

Neonatal heart rate variability: a contemporary scoping review of analysis methods and clinical applications

BACKGROUND

Neonatal heart rate variability (HRV) is widely used as a research tool. However, HRV calculation methods are highly variable making it difficult for comparisons between studies.

OBJECTIVES

To describe the different types of investigations where neonatal HRV was used, study characteristics, and types of analyses performed.

ELIGIBILITY CRITERIA

Human neonates ≤1 month of corrected age.

SOURCES OF EVIDENCE

A protocol and search strategy of the literature was developed in collaboration with the McGill University Health Center's librarians and articles were obtained from searches in the Biosis, Cochrane, Embase, Medline and Web of Science databases published between 1 January 2000 and 1 July 2020.

CHARTING METHODS

A single reviewer screened for eligibility and data were extracted from the included articles. Information collected included the study characteristics and population, type of HRV analysis used (time domain, frequency domain, non-linear, heart rate characteristics (HRC) parameters) and clinical applications (physiological and pathological conditions, responses to various stimuli and outcome prediction).

RESULTS

Of the 286 articles included, 171 (60%) were small single centre studies (sample size <50) performed on term infants (n=136). There were 138 different types of investigations reported: physiological investigations (n=162), responses to various stimuli (n=136), pathological conditions (n=109) and outcome predictor (n=30). Frequency domain analyses were used in 210 articles (73%), followed by time domain (n=139), non-linear methods (n=74) or HRC analyses (n=25). Additionally, over 60 different measures of HRV were reported; in the frequency domain analyses alone there were 29 different ranges used for the low frequency band and 46 for the high frequency band.

CONCLUSIONS

Neonatal HRV has been used in diverse types of investigations with significant lack of consistency in analysis methods applied. Specific guidelines for HRV analyses in neonates are needed to allow for comparisons between studies.

Parent-child bonding and attachment during pregnancy and early childhood following congenital heart disease diagnosis

Diagnosis and treatment of congenital heart disease (CHD) can present challenges to the developing parent-child relationship due to periods of infant hospitalization and intensive medical care, parent-infant separations, child neurodevelopmental delay and feeding problems, and significant parent and child distress and trauma. Yet, the ways in which CHD may affect the parent-child relationship are not well-understood. We systematically reviewed the evidence on parental bonding, parent-child interaction, and child attachment following CHD diagnosis, according to a pre-registered protocol (CRD42019135687). Six electronic databases were searched for English-language studies comparing a cardiac sample (i.e., expectant parents or parents and their child aged 0-5 years with CHD) with a healthy comparison group on relational outcomes. Of 22 unique studies, most used parent-report measures (73%) and yielded mixed results for parental bonding and parent-child interaction quality. Observational results also varied, although most studies (4 of 6) found difficulties in parent-child interaction on one or more affective or behavioural domains (e.g., lower maternal sensitivity, lower infant responsiveness). Research on parental-fetal bonding, father-child relationships, and child attachment behaviour was lacking. Stronger evidence is needed to determine the nature, prevalence, and predictors of relational disruptions following CHD diagnosis, and to inform targeted screening, prevention, and early intervention programs for at-risk dyads.

Neonatal Skin-to-Skin Contact: Implications for Learning and Autonomic Nervous System Function in Infants With Congenital Heart Disease

Background:

Infants with complex congenital heart disease (CCHD) often develop neurodevelopmental disabilities. Cognitive abilities are associated with vagally mediated autonomic function. Skin-to-skin contact (SSC) interventions enhance infant neurodevelopment and autonomic function in other high-risk populations.

Aim:

To examine the effects of a neonatal SSC intervention on learning and autonomic function in 3-month-old infants: infants with CCHD who received neonatal SSC ( n = 10), typically developing (TD) infants ( n = 16), and infants with CCHD without SSC ( n = 10).

Methods:

This secondary data analysis measured cognitive function using the mobile paradigm (MP), a classic measure of learning based on operant conditioning. Autonomic function was assessed with heart rate (HR) and HR variability (HRV). Data were analyzed with repeated-measures general linear mixed modeling with α = .10 for this exploratory study.

Results:

Learning rates were TD = 75%, cardiac-SSC = 70%, and cardiac-control = 40%. Learners demonstrated significant reductions in HRV during the MP; nonlearners exhibited no change. TD and cardiac-SSC groups exhibited increases in HR and reductions in HRV during the MP. No significant changes occurred in the cardiac-control group. Nonlinear HRV during the MP differed only in the TD group.

Conclusions:

Findings suggest improvements in cognitive and autonomic development in 3-month-old infants with CCHD who received neonatal SSC. Learning and autonomic function results in infants with CCHD who had not received SSC suggest reduced capacity to muster the physiologic resources to carry out this cognitive task. Findings provide preliminary evidence in support of implementation of SSC with infants with CCHD and support additional research.

Heart Rate Variability as a Feeding Intervention Outcome Measure in the Preterm Infant

BACKGROUND

Feeding interventions for preterm infants aim to reduce the physiologic stress of feeding to promote growth. Heart rate variability (HRV) is a potential noninvasive measure of physiologic stress that may be useful for evaluating efficacy of feeding interventions.

PURPOSE

To evaluate whether HRV is a sensitive measure of physiologic stress compared with standard physiologic outcomes in the context of a feeding intervention study.

METHODS

This was a secondary analysis of a within-subjects, cross-over design study comparing usual care feeding with a gentle, coregulated (CoReg) feeding approach in 14 infants born less than 35 weeks' postmenstrual age. HRV indices were calculated from electrocardiogram data and compared with standard physiologic outcomes, including oxygen saturation (Spo2), respiratory rate (RR), apnea, heart rate (HR), and bradycardia. Data were analyzed using linear mixed modeling.

RESULTS

Infants fed using the CoReg approach had fewer apneic events and higher RR, suggesting they were able to breathe more during feeding. No statistically significant differences were found in SpO2, HR, bradycardia, or high frequency power (the most commonly reported measure of HRV). Infants fed using the usual care approach had significantly higher SD12, a measure of HRV indicating randomness in the HR, which is a potential indicator of elevated stress.

IMPLICATIONS FOR PRACTICE

SD12 was more sensitive to stress than SpO2, HR, and bradycardia. The utility of HRV as a measure of feeding outcomes in clinical practice needs further exploration.

IMPLICATIONS FOR RESEARCH

Further exploration of HRV as an intervention outcome measure is needed, particularly evaluating nonlinear indices, such as SD12.

Patterned auditory stimulation and suck dynamics in full-term infants

AIM

To determine whether patterned auditory stimuli, designed to mimic the natural burst-pause pattern evident in non-nutritive suck (NNS) with variations to the intraburst frequency, alter infants' NNS and cardiorespiratory patterning.

METHODS

Sixteen healthy full-term infants participated in this study. Infants were fitted with electrocardiogram electrodes and a respiratory belt to measure cardiorespiratory patterning. Infants were offered a custom pacifier attached to a pressure transducer to measure NNS. Prior to the start of the study, a two-minute NNS and cardiorespiratory baseline was attained. Next, three auditory stimulation conditions were presented in the form of sucking clicks at interburst frequencies of 1, 2 and 4 Hz. Each of the three frequencies was played for two minutes.

RESULTS

Separate repeated-measures ANOVAs revealed significant differences in NNS burst duration (p = 0.013), NNS cycles/burst (p = 0.010) and NNS bursts/minute (p = 0.005) across auditory stimulation conditions. No significant differences were evident in the cardiorespiratory outcomes.

CONCLUSION

We found that patterned auditory stimulation significantly reduced NNS dynamics and had no effect on cardiorespiratory patterning. The findings further suggest that infants attempted to modulate their suck pattern to the patterned acoustic stimuli by shortening their burst durations with fewer cycles per burst.

Postnatal Cardiac Autonomic Nervous Control in Pediatric Congenital Heart Disease

Congenital heart disease is the most common congenital defect. During childhood, survival is generally good but, in adulthood, late complications are not uncommon. Abnormal autonomic control in children with congenital heart disease may contribute considerably to the pathophysiology of these long term sequelae. This narrative review of 34 studies aims to summarize current knowledge on function of the autonomic nervous system in children with a congenital heart defect. Large scale studies that measure both branches of the nervous system for prolonged periods of time in well-defined patient cohorts in various phases of childhood and adolescence are currently lacking. Pending such studies, there is not yet a good grasp on the extent and direction of sympathetic and parasympathetic autonomic function in pediatric congenital heart disease. Longitudinal studies in homogenous patient groups linking autonomic nervous system function and clinical outcome are warranted.

A pilot study: the role of the autonomic nervous system in cardiorespiratory regulation in infant feeding

AIM

The purpose of this pilot study was to examine the interplay between the parasympathetic (PNS) and sympathetic nervous systems' (SNS) contributions to prefeeding, feeding and satiation in young, healthy infants.

METHOD

This prospective study was completed on eleven full-term infants, less than 6 months old. Respiratory rate, heart rate, heart rate variability (HRV), electrodermal activity and low-frequency/high-frequency heart rate variability ratio were sampled from the infant during prefeeding, feeding and satiation periods.

RESULTS

A repeated-measures ANOVA revealed a significant difference in respiratory patterning during the three feeding phases (p = .049); however, none of the other physiological measures reached significance. An emerging trend across physiological measures suggests that the feeding phase was influenced by the SNS with increasing respiratory rate, heart rate, low-frequency HRV, electrodermal activity and decreasing high-frequency HRV compared to the prefeeding and satiation phases, which were influenced predominantly by the PNS.

CONCLUSION

Respiration rate increased significantly during the feeding phase compared to prefeeding and postfeeding phases. Emerging trends indicate a pattern of alternating relative tone in PNS versus SNS across feeding phases - with SNS predominating the feeding phase. More clinical research examining the SNS and PNS contributions to feeding should be completed across patient populations.