Effects of body position on thermal, cardiorespiratory and metabolic activity in low birth weight infants

Evidence Base for 2022 Updated Recommendations for a Safe Infant Sleeping Environment to Reduce the Risk of Sleep-Related Infant Deaths

Every year in the United States, approximately 3500 infants die of sleep-related infant deaths, including sudden infant death syndrome (SIDS) (International Statistical Classification of Diseases and Related Health Problems 10th Revision [ICD-10] R95), ill-defined deaths (ICD-10 R99), and accidental suffocation and strangulation in bed (ICD-10 W75). After a substantial decline in sleep-related deaths in the 1990s, the overall death rate attributable to sleep-related infant deaths have remained stagnant since 2000, and disparities persist. The triple risk model proposes that SIDS occurs when an infant with intrinsic vulnerability (often manifested by impaired arousal, cardiorespiratory, and/or autonomic responses) undergoes an exogenous trigger event (eg, exposure to an unsafe sleeping environment) during a critical developmental period. The American Academy of Pediatrics recommends a safe sleep environment to reduce the risk of all sleep-related deaths. This includes supine positioning; use of a firm, noninclined sleep surface; room sharing without bed sharing; and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include human milk feeding; avoidance of exposure to nicotine, alcohol, marijuana, opioids, and illicit drugs; routine immunization; and use of a pacifier. New recommendations are presented regarding noninclined sleep surfaces, short-term emergency sleep locations, use of cardboard boxes as a sleep location, bed sharing, substance use, home cardiorespiratory monitors, and tummy time. In addition, additional information to assist parents, physicians, and nonphysician clinicians in assessing the risk of specific bed-sharing situations is included. The recommendations and strength of evidence for each recommendation are published in the accompanying policy statement, which is included in this issue.

Hyperthermia and Heat Stress as Risk Factors for Sudden Infant Death Syndrome: A Narrative Review

BACKGROUND AND OBJECTIVES

Heat stress and hyperthermia are common findings in sudden infant death syndrome (SIDS) victims. It has been suggested that thermal stress can increase the risk of SIDS directly via lethal hyperthermia or indirectly by altering autonomic functions. Major changes in sleep, thermoregulation, cardiovascular function, and the emergence of circadian functions occur at the age at which the risk of SIDS peaks-explaining the greater vulnerability at this stage of development. Here, we review the literature data on (i) heat stress and hyperthermia as direct risk factors for SIDS, and (ii) the indirect effects of thermal loads on vital physiological functions.

RESULTS

Various situations leading to thermal stress (i.e., outdoors temperatures, thermal insulation from clothing and bedding, the prone position, bed-sharing, and head covering) have been analyzed. Hyperthermia mainly results from excessive clothing and bedding insulation with regard to the ambient thermal conditions. The appropriate amount of clothing and bedding thermal insulation for homeothermia requires further research. The prone position and bed-sharing do not have major thermal impacts; the elevated risk of SIDS in these situations cannot be explained solely by thermal factors. Special attention should be given to brain overheating because of the head's major role in body heat losses, heat production, and autonomic functions. Thermal stress can alter cardiovascular and respiratory functions, which in turn can lead to life-threatening events (e.g., bradycardia, apnea with blood desaturation, and glottal closure). Unfortunately, thermal load impairs the responses to these challenges by reducing chemosensitivity, arousability, and autoresuscitation. As a result, thermal load (even when not lethal directly) can interact detrimentally with vital physiological functions.

CONCLUSIONS

With the exception of excessive thermal insulation (which can lead to lethal hyperthermia), the major risk factors for SIDS appears to be associated with impairments of vital physiological functions when the infant is exposed to thermal stress.

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.

Prone sleeping affects cardiovascular control in preterm infants in NICU

BACKGROUND

Prone sleeping is used in preterm infants undergoing intensive care to improve respiratory function, but evidence suggests that this position may compromise autonomic cardiovascular control. To test this hypothesis, this study assessed the effects of the prone sleeping position on cardiovascular control in preterm infants undergoing intensive care treatment during early postnatal life.

METHODS

Fifty-six preterm infants, divided into extremely preterm (gestational age (GA) 24-28 weeks, n = 23) and very preterm (GA 29-34 weeks, n = 33) groups, were studied weekly for 3 weeks in prone and supine positions, during quiet and active sleep. Heart rate (HR) and non-invasive blood pressure (BP) were recorded and autonomic measures of HR variability (HRV), BP variability (BPV), and baroreflex sensitivity (BRS) using frequency analysis in low (LF) and high (HF) bands were assessed.

RESULTS

During the first 3 weeks, prone sleeping increased HR, reduced BRS, and increased HF BPV compared to supine. LF and HF HRV were also lower prone compared to supine in very preterm infants. Extremely preterm infants had the lowest HRV and BRS measures, and the highest HF BPV.

CONCLUSIONS

Prone sleeping dampens cardiovascular control in early postnatal life in preterm infants, having potential implications for BP regulation in infants undergoing intensive care.

Transition to a Safe Home Sleep Environment for the NICU Patient

Of the nearly 3.8 million infants born in the United States in 2018, 8.3% had low birth weight (<2500 g [5.5 lb]) and 10% were born preterm (gestational age of <37 completed weeks). Many of these infants and others with congenital anomalies, perinatally acquired infections, and other disease require admission to a NICU. In the past decade, admission rates to NICUs have been increasing; it is estimated that between 10% and 15% of infants will spend time in a NICU, representing approximately 500 000 neonates annually. Approximately 3600 infants die annually in the United States from sleep-related deaths, including sudden infant death syndrome International Classification of Diseases, 10th Revision (R95), ill-defined deaths (R99), and accidental suffocation and strangulation in bed (W75). Preterm and low birth weight infants are particularly vulnerable, with an incidence of death 2 to 3 times greater than healthy term infants. Thus, it is important for health care professionals to prepare families to maintain their infant in a safe sleep environment, as per the recommendations of the American Academy of Pediatrics. However, infants in the NICU setting commonly require care that is inconsistent with infant sleep safety recommendations. The conflicting needs of the NICU infant with the necessity to provide a safe sleep environment before hospital discharge can create confusion for providers and distress for families. This technical report is intended to assist in the establishment of appropriate NICU protocols to achieve a consistent approach to transitioning NICU infants to a safe sleep environment as soon as medically possible, well before hospital discharge.

EFFECTS OF HAMMOCK POSITIONING ON CLINICAL PARAMETERS IN PRETERM INFANTS ADMITTED TO A NEONATAL INTENSIVE CARE UNIT: A SYSTEMATIC REVIEW

Objective:

To review the effects of the hammock positioning on clinical parameters of preterm newborn infants (PTNB) admitted to the Neonatal Intensive Care Unit (NICU).

Data sources:

This was a systematic review performed by searching the Pubmed, Lilacs, SciELO and PEDro databases. Intervention studies in English, Portuguese and Spanish that evaluated the effects of hammock positioning on clinical parameters of PTNB admitted to the NICU were selected. Three search strategies were used: 1) hammock positioning OR patient positioning AND intensive care units AND infant, newborn; 2) hammock positioning OR patient positioning AND intensive care units; 3) hammock positioning OR patient positioning AND intensive care units, neonatal. There was no restriction on the year of publication of the articles. Methodological quality was assessed by the PEDro scale.

Data synthesis:

Among 597 articles, only six were included and 139 neonates with gestational ages between 26 and 37 weeks and an average gestational weight <2240g were analyzed. Four studies included patients without any associated pathology and most of them placed the PTNB supine in hammock positioning. The duration of the intervention ranged from 15 to 180 minutes and most applied it at just one moment. There was an improvement in heart rate (HR), respiratory rate (RR) and pain (3/4 studies), as well as gains in peripheral oxygen saturation (SpO2) (2/4 studies). Only one study reported worsening of SpO2 with the intervention. The methodological quality of the studies was classified as low.

Conclusions:

Although this review suggests improvement with hammock positioning in HR, RR and pain in PTNB, the low methodological quality makes the results inconsistent.

Skin Temperatures of Back or Neck Are Better Than Abdomen for Indication of Average Proximal Skin Temperature During Sleep of School-Aged Children

PURPOSE

The tight association between sleep, body temperature regulation, and patterns of skin temperature change highlights the necessity for accurate and valid assessment of skin temperatures during sleep. With increased interest in this functional relationship in infants and children, it is important to identify where to best measure proximal skin temperature and whether it is possible to reduce the number of sites of measures, in order to limit the experimental effects in natural settings. Thus, the aim of this study was to determine the most suitable single skin temperature sites for representation of average proximal skin temperature during sleep of school aged children.

METHODS

Statistical analyses were applied to skin temperature data of 22 children, aged 6 to 12 years, measured over four consecutive school nights in their home settings, to compare single site measures of abdomen, back, neck, forehead and subclavicular skin temperatures (local temperatures) with average proximal skin temperatures.

RESULTS

Abdomen and forehead skin temperatures were significantly different (respectively higher and lower) to the other local proximal temperatures and to average proximal skin temperatures. Moreover, the time pattern of forehead temperature was very different from that of the other local temperatures.

CONCLUSIONS

Local forehead and abdomen skin temperatures are least suitable as single site representations of average proximal skin temperatures in school aged children when considering both the level and the time course pattern of the temperature across the night. Conversely, back and neck temperatures provide most fitting representation of average proximal skin temperatures.

Effect of Body Position on Cardiorespiratory Stabilization and Comfort in Preterm Infants on Continuous Positive Airway Pressure

PURPOSE

The purpose of the study is to investigate the effect of four body positions (supine, prone, left lateral, right lateral) on cardiorespiratory stabilization and comfort in preterm infants receiving Nasal Continuous Positive Airway Pressure (NCPAP).

DESIGN AND METHODS

In the study conducted as a randomized crossover design, the sample was composed of 20 preterm infants receiving NCPAP therapy. At each change of position, the baby was allowed to stabilize for 15 min, and heart rate and oxygen saturation values were recorded every 10 min for the next 60 min. The comfort levels of the infants in each position were evaluated at 30th and 60th minutes using the Premature Infant Comfort Scale.

RESULTS

At the end of the study, it was determined that there was no statistically significant difference between heart rate (p = .83), respiratory rate (p = .90) and oxygen saturation (p = .15) of the infants in terms of their positions. When the mean comfort scores of the preterm infants were compared in terms of position, it was found that there was a difference between the positions (p < .01). According to the scale evaluation, the highest comfort level of the infants was in the prone position, which was followed by right lateral, supine and left lateral positions.

PRACTICE IMPLICATIONS

Prone position was the most comfortable for preterm infants. However, comfort levels of preterm infants were also high enough in other positions so that no intervention is needed. In order to ensure comfort and cardiorespiratory stabilization, any of the four body positions can be chosen.

Comparison of Massage and Prone Position on Heart Rate and Blood Oxygen Saturation Level in Preterm Neonates Hospitalized in Neonatal Intensive Care Unit: A Randomized Controlled Trial

Background:

These days, most of the admitted infants in neonatal intensive care units (NICU) are premature infants. Infant massage and prone position has been recommended for several decades to have a positive effect on preterm and low birth weight infants. The objective of this study was to determine the effects of neonatal massage with prone positioning in preterm infants on Heart Rate (HR), and Oxygen Saturation (O₂Sa) status.

Materials and Methods:

This is a controlled randomized three-group clinical trial study conducted on hospitalized infants in selected hospitals of Alborz University of Medical Sciences in Karaj-Iran. There are about 75 preterm infants (33-37 weeks) who met inclusion criteria were randomly assigned to groups of position, massage as intervention groups, and a control group. Intervention (prone position and massage) was administrated for five straight days. The repeated measure ANOVA test was performed to evaluate and compare the effect of interventions. p value less than 0.05 was considered as statistical significance.

Results:

The Repeated Measure two-way Analysis of Variance (RM-ANOVA) result showed a significant difference in HR and SaO₂ in different time points among control, position and massage groups with RM-ANOVA (F_10,360 = 10.376, p < 0.001). HR values was reduced and SaO₂ values was increased in intervention groups with RM-ANOVA (F_5,360 = 2.323, p < 0.001).

Conclusions:

Results showed that massage and prone position equally led to the reduction of HR and increase of SaO₂, compared to control group.

Characteristics of Infant Deaths during Sleep While Under Nonparental Supervision

OBJECTIVE

To compare risk factors for infant sleep-related deaths under the supervision of parents and nonparents.

STUDY DESIGN

We conducted a secondary analysis of sleep-related infant deaths from 2004 to 2014 in the National Center for Fatality Review and Prevention Child Death Review Case Reporting System. The main exposure was supervisor at time of death. Primary outcomes included sleep position, location, and objects in the environment. Risk factors for parental vs nonparental supervisor were compared using χ² and multivariable logistic regression models. Risk factors associated with different nonparental supervisors were analyzed using χ².

RESULTS

Of the 10 490 deaths, 1375 (13.1%) occurred under nonparental supervision. Infants who died under nonparental supervision had higher adjusted odds of dying outside the home (OR 12.87, 95% CI 11.31-14.65), being placed prone (OR 1.61, 95% CI 1.39-1.86) or on their side (OR 1.35, 95% CI 1.12-1.62), or being found prone (OR 1.74, 95% CI 1.50-2.02). Among infants who died under nonparental supervision, those supervised by relatives or friends were more often placed on an adult bed or couch for sleep and bed sharing (P < .0001), and to have objects in the sleep environment (P = .01).

CONCLUSIONS

Infants who died of sleep-related causes under nonparental supervision were more likely to have been placed nonsupine. Among nonparental supervisors, relatives and friends were more likely to use unsafe sleep environments, such as locations other than a crib or bassinet and bed sharing. Pediatricians should educate parents that all caregivers must always follow safe sleep practices.

Interventions to prevent hypothermia at birth in preterm and/or low birth weight infants

BACKGROUND

Newborn admission temperature is a strong predictor of outcomes across all gestations. Hypothermia immediately after birth remains a worldwide issue and, if prolonged, is associated with harm. Keeping preterm infants warm is difficult even when recommended routine thermal care guidelines are followed in the delivery room.

OBJECTIVES

To assess the efficacy and safety of interventions designed for prevention of hypothermia in preterm and/or low birth weight infants applied within 10 minutes after birth in the delivery room, compared with routine thermal care or any other single/combination of intervention(s) also designed for prevention of hypothermia in preterm and/or low birth weight infants applied within 10 minutes after birth in the delivery room.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 5), MEDLINE via PubMed (1966 to 30 June 2016), Embase (1980 to 30 June 2016), and CINAHL (1982 to 30 June 2016). We also searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Trials using randomised or quasi-randomised allocations to test interventions designed to prevent hypothermia (apart from 'routine' thermal care) applied within 10 minutes after birth in the delivery room for infants at < 37 weeks' gestation and/or birth weight ≤ 2500 grams.

DATA COLLECTION AND ANALYSIS

We used Cochrane Neonatal methods when performing data collection and analysis.

MAIN RESULTS

Twenty-five studies across 15 comparison groups met the inclusion criteria, categorised as: barriers to heat loss (18 studies); external heat sources (three studies); and combinations of interventions (four studies).Barriers to heat loss Plastic wrap or bag versus routine carePlastic wraps improved core body temperature on admission to the neonatal intensive care unit (NICU) or up to two hours after birth (mean difference (MD) 0.58°C, 95% confidence interval (CI) 0.50 to 0.66; 13 studies; 1633 infants), and fewer infants had hypothermia on admission to the NICU or up to two hours after birth (typical risk ratio (RR) 0.67, 95% CI 0.62 to 0.72; typical risk reduction (RD) -0.25, 95% CI -0.29 to -0.20; number needed to treat for an additional beneficial outcome (NNTB) 4, 95% CI 4 to 5; 10 studies; 1417 infants). Risk of hyperthermia on admission to the NICU or up to two hours after birth was increased in infants in the wrapped group (typical RR 3.91, 95% CI 2.05 to 7.44; typical RD 0.04, 95% CI 0.02 to 0.06; number needed to treat for an additional harmful outcome (NNTH) 25, 95% CI 17 to 50; 12 studies; 1523 infants), but overall, fewer infants receiving plastic wrap were outside the normothermic range (typical RR 0.75, 95% CI 0.69 to 0.81; typical RD -0.20, 95% CI -0.26 to -0.15; NNTH 5, 95% CI 4 to 7; five studies; 1048 infants).Evidence was insufficient to suggest that plastic wraps or bags significantly reduce risk of death during hospital stay or other major morbidities, with the exception of reducing risk of pulmonary haemorrhage.Evidence of practices regarding permutations on this general approach is still emerging and has been based on the findings of only one or two small studies.External heat sourcesEvidence is emerging on the efficacy of external heat sources, including skin-to-skin care (SSC) versus routine care (one study; 31 infants) and thermal mattress versus routine care (two studies; 126 infants).SSC was shown to be effective in reducing risk of hypothermia when compared with conventional incubator care for infants with birth weight ≥ 1200 and ≤ 2199 grams (RR 0.09, 95% CI 0.01 to 0.64; RD -0.56, 95% CI -0.84 to -0.27; NNTB 2, 95% CI 1 to 4). Thermal (transwarmer) mattress significantly kept infants ≤ 1500 grams warmer (MD 0.65°C, 95% CI 0.36 to 0.94) and reduced the incidence of hypothermia on admission to the NICU, with no significant difference in hyperthermia risk.Combinations of interventionsTwo studies (77 infants) compared thermal mattresses versus plastic wraps or bags for infants at ≤ 28 weeks' gestation. Investigators reported no significant differences in core body temperature nor in the incidence of hypothermia, hyperthermia, or core body temperature outside the normothermic range on admission to the NICU.Two additional studies (119 infants) compared plastic bags and thermal mattresses versus plastic bags alone for infants at < 31 weeks' gestation. Meta-analysis of these two studies showed improvement in core body temperature on admission to the NICU or up to two hours after birth, but an increase in hyperthermia. Data show no significant difference in the risk of having a core body temperature outside the normothermic range on admission to the NICU nor in the risk of other reported morbidities.

AUTHORS' CONCLUSIONS

Evidence of moderate quality shows that use of plastic wraps or bags compared with routine care led to higher temperatures on admission to NICUs with less hypothermia, particularly for extremely preterm infants. Thermal mattresses and SSC also reduced hypothermia risk when compared with routine care, but findings are based on two or fewer small studies. Caution must be taken to avoid iatrogenic hyperthermia, particularly when multiple interventions are used simultaneously. Limited evidence suggests benefit and no evidence of harm for most short-term morbidity outcomes known to be associated with hypothermia, including major brain injury, bronchopulmonary dysplasia, retinopathy of prematurity, necrotising enterocolitis, and nosocomial infection. Many observational studies have shown increased mortality among preterm hypothermic infants compared with those who maintain normothermia, yet evidence is insufficient to suggest that these interventions reduce risk of in-hospital mortality across all comparison groups. Hypothermia may be a marker for illness and poorer outcomes by association rather than by causality. Limitations of this review include small numbers of identified studies; small sample sizes; and variations in methods and definitions used for hypothermia, hyperthermia, normothermia, routine care, and morbidity, along with lack of power to detect effects on morbidity and mortality across most comparison groups. Future studies should: be adequately powered to detect rarer outcomes; apply standardised morbidity definitions; focus on longer-term outcomes, particularly neurodevelopmental outcomes.

Adherence to Safe Sleep Recommendations by Families With Higher-order Multiples

BACKGROUND

More than 95% of higher-order multiples are born preterm and more than 90% are low birth weight, making this group of infants especially vulnerable to sudden infant death syndrome (SIDS). Emerging evidence suggests that families with twins face challenges adhering to the American Academy of Pediatrics (AAP) recommendations to reduce SIDS risks. Adherence to the AAP recommendations in families with higher-order multiples has not been described.

PURPOSE

This study describes SIDS risk reduction infant care practices for higher-order multiples during the first year of life.

METHODS

Mothers caring for higher-order multiple-birth infants were recruited from an online support group. An online survey was used to assess infant care practices when the infants were first brought home from the hospital as well as at the time of the survey.

RESULTS

Ten mothers of triplets and 4 mothers of quadruplets responded. Less than 80% of the mothers practiced "back to sleep" immediately postdischarge. Supine sleep positioning decreased over time, particularly during daytime naps. Only 50% of the infants shared the parents' bedroom and approximately 30% bed-shared with their siblings. Sleep-time pacifier use was low.

IMPLICATIONS FOR PRACTICE

Safe sleep education must include specific questions regarding home sleeping arrangements, encouragement of breast milk feedings, supine positioning, and pacifier use at every sleep for higher-order multiple infants well before discharge in order for parents to plan a safe sleep environment at home.

IMPLICATIONS FOR RESEARCH

Prospective studies to identify barriers and facilitators can inform future strategies supporting adherence to safe sleep practices for higher-order multiple infants.

Effect of Body Position on Energy Expenditure of Preterm Infants as Determined by Simultaneous Direct and Indirect Calorimetry

Background Indirect calorimetry is the standard method for estimating energy expenditure in clinical research. Few studies have evaluated indirect calorimetry in infants by comparing it with simultaneous direct calorimetry. Our purpose was (1) to compare the energy expenditure of preterm infants determined by these two methods, direct calorimetry and indirect calorimetry; and (2) to examine the effect of body position, supine or prone, on energy expenditure. Study Design We measured energy expenditure by simultaneous direct (heat loss by gradient-layer calorimeter corrected for heat storage) and indirect calorimetry (whole-body oxygen consumption and carbon dioxide production) in 15 growing preterm infants during two consecutive interfeeding intervals, once in the supine position and once in the prone position. Results The mean energy expenditure for all measurements in both positions did not differ significantly by the method used: 2.82 (standard deviation [SD] 0.42) kcal/kg/h by direct calorimetry and 2.78 (SD 0.48) kcal/kg/h by indirect calorimetry. The energy expenditure was significantly lower, by 10%, in the prone than in the supine position, whether examined by direct calorimetry (2.67 vs. 2.97 kcal/kg/h, p < 0.001) or indirect calorimetry (2.64 vs. 2.92 kcal/kg/h, p = 0.017). Conclusion Direct calorimetry and indirect calorimetry gave similar estimates of energy expenditure. Energy expenditure was 10% lower in the prone position than in the supine position.

SIDS and Other Sleep-Related Infant Deaths: Evidence Base for 2016 Updated Recommendations for a Safe Infant Sleeping Environment

Approximately 3500 infants die annually in the United States from sleep-related infant deaths, including sudden infant death syndrome (SIDS), ill-defined deaths, and accidental suffocation and strangulation in bed. After an initial decrease in the 1990s, the overall sleep-related infant death rate has not declined in more recent years. Many of the modifiable and nonmodifiable risk factors for SIDS and other sleep-related infant deaths are strikingly similar. The American Academy of Pediatrics recommends a safe sleep environment that can reduce the risk of all sleep-related infant deaths. Recommendations for a safe sleep environment include supine positioning, use of a firm sleep surface, room-sharing without bed-sharing, and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include avoidance of exposure to smoke, alcohol, and illicit drugs; breastfeeding; routine immunization; and use of a pacifier. New evidence and rationale for recommendations are presented for skin-to-skin care for newborn infants, bedside and in-bed sleepers, sleeping on couches/armchairs and in sitting devices, and use of soft bedding after 4 months of age. In addition, expanded recommendations for infant sleep location are included. The recommendations and strength of evidence for each recommendation are published in the accompanying policy statement, "SIDS and Other Sleep-Related Infant Deaths: Updated 2016 Recommendations for a Safe Infant Sleeping Environment," which is included in this issue.

Semi-Prone Position Can Influence Variability in Respiratory Rate of Premature Infants Using Nasal CPAP

To determine the effect of positions (supine, lateral, semiprone) on the physiological parameters (HR, RR, SpO2) of premature infants receiving NCPAP who were non-oxygen-dependent and non-BPD, and to identify significant clinical changes associated with these variables.

METHODS

A crossover study design with three different positions in the assigned sequence (supine-supine, supine-lateral and supine-semiprone) was used, and each position was maintained for 1h. The subjects' vital signs were recorded 30 min after initiation of each position and measured for 30 min.

RESULTS

Forty-seven infants with a median GA of 28.6 weeks (range 26-35) were studied, and their median BW was 1210g (range 776-2920). Overall, position-related effects showed significant difference in the variability in RR (OR=0.68; CI 0.51-0.89), with the variability in RR being significantly lower in the semiprone position. The lateral position was associated with increased RR (B=2.9; p=0.02). Previous use of ventilator (PUV) was associated with increased HR, whereas BW and GA were negatively associated with higher HR. Cesarean birth, use of surfactant and PUV were associated with lower SpO2, whereas BW and GA were correlated with higher SpO2. GA was identified as a protective factor, while PUV was a risk factor for the variability in both HR and SpO2.

CONCLUSIONS

Premature infants receiving NCPAP sleeping in the semiprone position may have more stable RR, while the lateral position did not improve RR. Thus, the semiprone and supine positions may be considered preferable when positioning the monitored premature infants with NCPAP.

Influence of prone positioning on premature newborn infant stress assessed by means of salivary cortisol measurement: pilot study

Objective

This study sought to assess the influence of prone positioning on the stress of newborn premature infants through the measurement of the salivary cortisol concentration and the evaluation of physiological and behavioral responses before and after changes in body positioning.

Methods

Saliva samples were collected from newborn infants at two different times: the first (corresponding to the baseline) after a period of 40 minutes during which the infants were not subjected to any manipulation and were placed in the lateral or supine position, and the second 30 minutes after placement in the prone position. Variables including heart rate, respiratory rate, peripheral oxygen saturation, and the Brazelton sleep score were recorded before, during, and at the end of the period in the prone position.

Results

The sample comprised 16 newborn premature infants (56.3% male) with a gestational age between 26 and 36 weeks, postnatal age between 1 and 33 days, birth weight of 935 to 3,050g, and weight at the time of intervention of 870 to 2,890g. During the intervention, six participants breathed room air, while the remainder received oxygen therapy. The median salivary cortisol concentration was lower in the prone position compared to baseline (0.13 versus 0.20; p=0.003), as was the median Brazelton sleep score (p=0.02). The average respiratory rate was lower after the intervention (54.88±7.15 versus 60±7.59; p=0.0004). The remainder of the investigated variables did not exhibit significant variation.

Conclusion

Prone positioning significantly reduced the salivary cortisol level, respiratory rate, and Brazelton sleep score, suggesting a correlation between prone positioning and reduction of stress in preterm infants.

Ambient Heat and Sudden Infant Death: A Case-Crossover Study Spanning 30 Years in Montreal, Canada

BACKGROUND

Climate change may lead to more severe and extreme heat waves in the future, but its potential impact on sudden infant death-a leading cause of infant mortality-is unclear.

OBJECTIVES

We sought to determine whether risk of sudden infant death syndrome (SIDS) is elevated during hot weather.

METHODS

We undertook a case-crossover analysis of all sudden infant deaths during warm periods in metropolitan Montreal, Quebec, Canada, from 1981 through 2010. Our analysis included a total of 196 certified cases of SIDS, including 89 deaths at 1-2 months of age, and 94 at 3-12 months. We estimated associations between maximum outdoor temperatures and SIDS by comparing outdoor temperatures on the day of or day before a SIDS event with temperatures on control days during the same month, using cubic splines to model temperature and adjusting for relative humidity.

RESULTS

Maximum daily temperatures of ≥ 29°C on the same day were associated with 2.78 times greater odds of sudden infant death relative to 20°C (95% CI: 1.64, 4.70). The likelihood of sudden death increased steadily with higher temperature. Associations were stronger for infants 3-12 months of age than for infants 1-2 months of age, with odds ratios of 3.90 (95% CI: 1.87, 8.13) and 1.73 (95% CI: 0.80, 3.73), respectively, for 29°C compared with 20°C on the day of the event.

CONCLUSIONS

High ambient temperature may be a novel risk factor for SIDS, especially at ≥ 3 months of age. Climate change and the higher temperatures that result may account for a potentially greater proportion of sudden infant deaths in the future.

[Influence of body position on the displacement of nasal prongs in preterm newborns receiving continuous positive airway pressure]

Objective:

To evaluate the influence of body position on the displacement of nasal prongs in preterm infants.

Methods:

This prospective, randomized, crossover study enrolled infants born at a mean gestational age of 29.7±2 weeks, birth weight of 1353±280g and 2.9±2.2 days of life, submitted to continuous positive airway pressure by nasal prongs. The main outcome was the number of times that the nasal prongs were displaced following infant positioning in the following body positions: prone, right lateral, left lateral, and supine, according to a pre-established random order. Moreover, cardiorespiratory variables (respiratory rate, heart rate, and oxygen saturation) were evaluated for each body position. Data for each position were collected every 10 min, over a period of 60 min. An occurrence was defined when the nasal prongs were displaced from the nostrils after 3 min in the desired position, requiring intervention of the examiner.

Results:

Among the 16 studied infants, the occurrence of nasal prong displacement was only observed in the prone position (9 infants - 56.2%) and in the left lateral position (2 infants - 12.5%). The number of times that the prongs were displaced was 11 in the prone position (7 within the first 10min) and 2 in the left lateral position (1 within the first 10min). No clinically significant changes were observed in the cardiorespiratory variables.

Conclusions:

Maintenance of the nasal prongs to provide adequate noninvasive respiratory support was harder in the prone position.

Prone positioning decreases cardiac output and increases systemic vascular resistance in neonates

OBJECTIVE

To evaluate the cardiovascular response to short-term prone positioning in neonates.

STUDY DESIGN

In this prospective study, we continuously monitored heart rate (HR), stroke volume (SV) and cardiac output (CO) by electrical velocimetry in hemodynamically stable neonates in each of the following positions for 10 min: supine, prone and back-to-supine position. Skin blood flow (SBF) was also continuously assessed on the forehead or foot using Laser Doppler technology. Systemic vascular resistance (SVR) index was calculated as mean blood pressure (BP)/CO. Data were analyzed using repeated measures analysis of variance.

RESULTS

Thirty neonates (gestational age: 35±4 weeks; postmenstrual age: 36±3 weeks) were enrolled. HR did not change in response to positioning. However, in prone position, SV, CO and SBF decreased and SVR index increased from 1.5±0.3 to 1.3±0.3 ml kg(-1) (mean ±s.d., P<0.01), 206±44 to 180±41 ml kg(-1) min(-1) (P<0.01), 0.54±0.30 to 0.44±0.29 perfusion units (P<0.01) and 0.25±0.06 to 0.30±0.07 mm Hg ml(-1) kg(-1) min(-1) (P<0.01), respectively. After placing the infants back-to-supine position, SV, CO, SBF and SVR index returned to baseline. The above pattern of cardiovascular changes was consistent in vast majority of the studied neonates.

CONCLUSIONS

Short-term prone positioning is associated with decreased SV, CO and SBF and increased calculated SVR index.

Predictors of unfavorable thermal outcome during newborn emergency retrievals

OBJECTIVE

Maintenance of normal body temperature is a challenge during transports. We aimed to identify predisposing factors for unfavorable thermal outcome during emergency retrievals of neonates.

METHODS

Demographic data and clinical variables for transports performed over a 2-year period were extracted from the Newborn Emergency Transport Service (Victoria, Australia) database. Arrival temperatures outside normothermia (36.5°-37.5°C) were defined as an unfavorable outcome.

RESULTS

Normothermia on arrival at the receiving hospital was achieved in 78% of 1,261 transports. The strongest predictor of unfavorable thermal outcome was an abnormal temperature at the start of the retrieval (odds ratio [OR] = 8.04; 95% confidence interval [CI], 5.91-10.95; P < .001) followed by very low weight on transport (< 1,500 g; OR = 2.49; 95% CI, 1.63-3.80; P < .001) and respiratory support (OR = 1.81; 95% CI, 1.29-2.54; P = .001). Medications (eg, inotropes and sedation/muscle relaxation) or central/peripheral venous/arterial lines were not significant predictors of outcome when temperature at retrieval start, weight at transport, and respiratory support were adjusted as cofactors. Mode of transport (road, fixed wing, or rotary wing aircraft) and outside temperature were not associated with thermal outcome.

CONCLUSION

Abnormal temperature at the start of the retrieval, very low transport weight, and respiratory support were strong predictors of unfavorable thermal outcome during neonatal emergency transports.

[Utility of a physiologic stability index based on Transport Risk Index of Physiologic Stability (TRIPS) for the evaluation of infants transferred to a specialized hospital]

BACKGROUND

Neonatal mortality is a public health priority. We review the physiological instability of the newborn after a transfer, which contributes to increased neonatal mortality. The objective of this work was to determine whether the Transport Risk Index of Physiologic Stability (TRIPS) in newborns transferred to the Neonatal Intensive Care Unit of a secondary hospital serves as a predictor of early neonatal mortality.

METHODS

We use the TRIPS to predict neonatal death in the first 7 days after patients' admission.

RESULTS

Neonatal mortality at 7 days after admission is related to the TRIPS rating. The score of the survivors and neonatal deaths show a significant difference (p: 0.009). For a score of 16, a sensitivity of 62% and a specificity of 84%; area under the curve of 0.757 was determined.

CONCLUSIONS

Physiological index weighting using TRIPS is a good predictor of neonatal mortality. It is important to establish measures to improve physiological stability of the newborn before, during and after the transfer in order to reduce neonatal mortality.

An evidence-based safe sleep teaching program

This column describes the experience of the units practice council in developing an evidence-based practice teaching program focused on safe sleep for newborn infants.

Effect of body position on preterm newborns receiving continuous positive airway pressure

AIM

To evaluate the effect of body position on the cardiorespiratory indicators of preterm newborns receiving nasal continuous positive airway pressure (CPAP).

METHODS

Analytical, observational, prospective, cross-sectional, randomised crossover study was carried out on sixteen newborns that received nasal CPAP. The infants had a mean gestational age of 29.7 ± 2 weeks and birthweight of 1353 ± 280 g. Cardiorespiratory indicators (respiratory rate, heart rate and oxygen saturation) were evaluated in each infant in the supine, prone and right and left lateral decubitus positions at intervals of 10 min over a period of 60 min.

RESULTS

The cardiorespiratory indicators were similar and within the normal range in the four decubitus positions. There was no difference in respiratory or heart rate between body positions. Although they showed desirable values, oxygen saturation was significantly lower in left lateral decubitus (96.6 ± 1.7%) when compared to the supine (97.1 ± 1.3%) and prone positions (97.4 ± 1.1%) (p = 0.00) and was also significantly lower in right lateral decubitus (96.9 ± 1.4%) when compared to the prone position (p = 0.00).

CONCLUSION

We found no preferential decubitus position for preterm newborns receiving nasal CPAP, the supine position may be a choice, but the left and right lateral positions were less advantageous in terms of oxygen saturation.

Comparison the effect of Sleep Positioning on Cardiorespiratory Rate in Noninvasive Ventilated Premature Infants

Background:

Results of several studies suggest that prone position is beneficial in improving the preterm infants’ cardio-respiratory status. Previous studies showed opposite results, and also there is not any available clear study about the effect of this position on cardio-respiratory rates of Nasal Continuous Positive Airway Pressure (N-CPAP) treating premature infants.

Objectives:

This study aimed at comparing supine and prone positions on cardio-respiratory rates of premature infants with respiratory distress syndrome (RDS) who were treated using N-CPAP.

Patients and Methods:

This was a cross over study which was performed in 2010 on 44 hospitalized 29-34 weeks gestation premature infants who were receiving N-CPAP in Neonatal Intensive Care Unit of Al-Zahra Hospital of Tabriz University of Medical Sciences. Infants were randomly assigned into two groups, and the first group was placed in prone at first and then in supine, and the position of second group was at first supine and then prone. Infants’ Heart Rate (HR) and Respiratory Rate (RR) were assessed three times in each position for 30 minutes. The data was recorded in a data-collection form, and demographic data was analyzed using t test, Chi square and Fisher exact test. Also, repeated measurement ANOVA and Tukey post-hoc tests were used.

Results:

There was a significant difference in HR and RR of premature infants who were similar in gestational age and clinical condition and placed in two positions. Premature infants’ HR and RR became lower at prone position than supine in both groups. So it can be concluded that prone position could decrease infants HR and RR, but supine position might increase them (P < 0.05).

Conclusion:

Our findings support prone positioning for premature infants. Therefore, it is advisable to NICU staff that if there is no obstacle for changing the infant’s position, prone position in infants with respiratory complications during receiving N-CPAP in NICU can be useful. Regarding the fact that prone position is a risk factor for sudden infant death syndrome , prone position should be only used when the newborn is being supervised carefully.

SIDS and other sleep-related infant deaths: expansion of recommendations for a safe infant sleeping environment

Despite a major decrease in the incidence of sudden infant death syndrome (SIDS) since the American Academy of Pediatrics (AAP) released its recommendation in 1992 that infants be placed for sleep in a nonprone position, this decline has plateaued in recent years. Concurrently, other causes of sudden unexpected infant death occurring during sleep (sleep-related deaths), including suffocation, asphyxia, and entrapment, and ill-defined or unspecified causes of death have increased in incidence, particularly since the AAP published its last statement on SIDS in 2005. It has become increasingly important to address these other causes of sleep-related infant death. Many of the modifiable and nonmodifiable risk factors for SIDS and suffocation are strikingly similar. The AAP, therefore, is expanding its recommendations from being only SIDS-focused to focusing on a safe sleep environment that can reduce the risk of all sleep-related infant deaths including SIDS. The recommendations described in this report include supine positioning, use of a firm sleep surface, breastfeeding, room-sharing without bed-sharing, routine immunization, consideration of a pacifier, and avoidance of soft bedding, overheating, and exposure to tobacco smoke, alcohol, and illicit drugs. The rationale for these recommendations is discussed in detail in this technical report. The recommendations are published in the accompanying "Policy Statement--Sudden Infant Death Syndrome and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment," which is included in this issue (www.pediatrics.org/cgi/doi/10.1542/peds.2011-2220).

Graphical Exploration of Dimensions of Preterm Infant Growth in Weight in Association With Biological, Nutritional, and Energy Expenditure Conditions

The small sample sizes of studies involving preterm infants limit the use of statistics for examination of multivariate conditions contributing to clinically important growth dimensions of weight: rate of weight gain, body composition (fat-free and fat mass), and weight relative to reference infants (z score). The authors used graphical analyses, including multivariate proportional matrix, parallel coordinates, and bivariate plots with regression lines and splines, to explore specific variables derived from a theoretical model of biological, nutritional intake, and energy expenditure conditions influencing growth dimensions. The sample included 28 infants in 4 birth-weight categories: extremely low (<1,000 g), very low/smaller (1,000—1,249 g), very low/larger (1,250—1,499 g), and low (1,500—1,750 g). The authors examined the rate of weight gain before and after nipple feeding initiation. Fat-free mass was estimated with total body water and fetal reference data, and fat mass with skinfold thicknesses. Despite infants achieving the expected rate of weight gain for a fetus of the same postconceptional age, by hospital discharge 13 infants showed growth restriction with weight <10th centile. Infants with respiratory distress syndrome history were highest in negative z-score change from regain of birth weight to discharge, despite higher ordering on protein intake and fat-free mass. Graphical analyses provided visual patterns of distributions and orderings of measures of multiple variables that, taken together, identified potential influencing conditions and raised questions for further study. Other variables, including feeding protocols and practices, infant feeding competence, and health status, may contribute to variability in weight growth dimensions and influence relationships with biologic, nutritional, and energy expenditure conditions.

Cardiovascular control during sleep in infants: Implications for Sudden Infant Death Syndrome

In infants the cardiorespiratory system undergoes significant functional maturation after birth and these changes are sleep-state dependent. Given the immaturity of these systems it is not surprising that infants are at risk of cardiorespiratory instability, especially during sleep. A failure of cardiovascular control mechanisms in particular is believed to play a role in the final event of Sudden Infant Death Syndrome (SIDS). The "triple risk model" describes SIDS as an event that results from the intersection of three overlapping factors: (1) a vulnerable infant, (2) a critical development period in homeostatic control, and (3) an exogenous stressor. This review summarises normal development of cardiovascular control during sleep in infants and describes the association of impaired cardiovascular control with the three overlapping factors proposed to be involved in SIDS pathogenesis.

Interventions to prevent hypothermia at birth in preterm and/or low birthweight infants

BACKGROUND

Keeping vulnerable preterm infants warm is problematic even when recommended routine thermal care guidelines are followed in the delivery suite.

OBJECTIVES

To assess efficacy and safety of interventions designed for prevention of hypothermia in preterm and/or low birthweight infants applied within 10 minutes after birth in the delivery suite compared with routine thermal care.

SEARCH STRATEGY

We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG). The review was updated in October 2009.

SELECTION CRITERIA

Trials using randomised or quasi-randomised allocations to test a specific intervention designed to prevent hypothermia, (apart from 'routine' thermal care) applied within 10 minutes after birth in the delivery suite to infants of < 37 weeks' gestational age or birthweight </= 2500 g.

DATA COLLECTION AND ANALYSIS

We used the methods of the CNRG for data collection and analysis.

MAIN RESULTS

1) Barriers to heat loss [5 studies; plastic wrap or bag (3), plastic cap (1), stockinet cap (1)]:Plastic wraps or bags were effective in reducing heat losses in infants < 28 weeks' gestation (4 studies, n = 223; WMD 0.68 degrees C; 95% CI 0.45, 0.91), but not in infants between 28 to 31 week's gestation. Plastic caps were effective in reducing heat losses in infants < 29 weeks' gestation (1 study, n = 64; MD 0.80 degrees C; 95% CI 0.41, 1.19). There was insufficient evidence to suggest that either plastic wraps or plastic caps reduce the risk of death within hospital stay. There was no evidence of significant differences in other clinical outcomes for either the plastic wrap/bag or the plastic cap comparisons. Stockinet caps were not effective in reducing heat losses.2) External heat sources [2 studies; skin-to-skin (1), transwarmer mattress (1)]:Skin-to-skin care (SSC) was shown to be effective in reducing the risk of hypothermia when compared to conventional incubator care for infants (1 study, n = 31; RR 0.09; 95% CI 0.01, 0.64). The transwarmer mattress reduced the incidence of hypothermia on admission to NICU in VLBW infants (1 study, n = 24; RR 0.30; 95% CI 0.11, 0.83).

AUTHORS' CONCLUSIONS

Plastic wraps or bags, plastic caps, SSC and transwarmer mattresses all keep preterm infants warmer leading to higher temperatures on admission to neonatal units and less hypothermia. However, the small numbers of infants and studies and the absence of long-term follow-up mean that firm recommendations for clinical practice cannot be given.

Interactions among peripheral perfusion, cardiac activity, oxygen saturation, thermal profile and body position in growing low birth weight infants

AIMS

To investigate the correlation between the 'perfusion index' (PI) and other commonly used estimates of cutaneous blood flow [heart rate (HR), surface temperatures (ST) and central-to-peripheral thermal gradients (C-P grad)] and to use this new non-invasive tool to compare differences between prone and supine sleep position in low birth weight (LBW) infants.

METHODS

Six-hour continuous recordings of pulse oximetry, cardiac activity and absolute ST from three sites (flank, forearm and leg), along with minute-to-minute assessment of behavioural states were performed in 31 LBW infants. Infants were randomly assigned to the prone or supine position for the first 3 h and then reversed for the second 3 h. PI data were correlated with HR and C-P grad, and compared across sleep positions during quiet sleep (QS) and active sleep (AS).

RESULTS

Perfusion index correlated significantly with HR (r(2) = 0.40) and flank-to-forearm thermal gradient (r(2) = 0.28). In the prone position during QS, infants exhibited higher PI (3.7 +/- 0.9 vs. 3.1 +/- 0.7), HR (158.4 +/- 8.9 vs. 154.1 +/- 8.8 bpm), SpO(2) (95.8 +/- 2.6 vs. 95.2 +/- 2.6%), flank (36.7 +/- 0.4 vs. 36.5 +/- 0.4 degrees C), forearm (36.1 +/- 0.6 vs. 35.5 +/- 0.4 degrees C) and leg (35.4 +/- 0.7 vs. 34.7 +/- 0.7 degrees C) temperatures and narrower flank-to-forearm (0.6 +/- 0.4 vs. 0.9 +/- 0.3 degrees C) and flank-to-leg (1.3 +/- 0.6 vs. 1.8 +/- 0.7 degrees C) gradients, compared to those of the supine position. Similar differences were observed during AS.

CONCLUSION

Perfusion index is a good non-invasive estimate of tissue perfusion. Prone sleeping position is associated with a higher PI, possibly reflecting thermoregulatory adjustments in cardiovascular control. The effects of these position-related changes may have important implications for the increased risk for sudden infant death syndrome in prone position.