Controlled Trial of Two Incremental Milk-Feeding Rates in Preterm Infants.

BACKGROUND: Observational data have shown that slow advancement of enteral feeding volumes in preterm infants is associated with a reduced risk of necrotizing enterocolitis but an increased risk of late-onset sepsis. However, data from randomized trials are limited. METHODS: We randomly assigned very preterm or very-low-birth-weight infants to daily milk increments of 30 ml per kilogram of body weight (faster increment) or 18 ml per kilogram (slower increment) until reaching full feeding volumes. The primary outcome was survival without moderate or severe neurodevelopmental disability at 24 months. Secondary outcomes included components of the primary outcome, confirmed or suspected late-onset sepsis, necrotizing enterocolitis, and cerebral palsy. RESULTS: Among 2804 infants who underwent randomization, the primary outcome could be assessed in 1224 (87.4%) assigned to the faster increment and 1246 (88.7%) assigned to the slower increment. Survival without moderate or severe neurodevelopmental disability at 24 months occurred in 802 of 1224 infants (65.5%) assigned to the faster increment and 848 of 1246 (68.1%) assigned to the slower increment (adjusted risk ratio, 0.96; 95% confidence interval [CI], 0.92 to 1.01; P = 0.16). Late-onset sepsis occurred in 414 of 1389 infants (29.8%) in the faster-increment group and 434 of 1397 (31.1%) in the slower-increment group (adjusted risk ratio, 0.96; 95% CI, 0.86 to 1.07). Necrotizing enterocolitis occurred in 70 of 1394 infants (5.0%) in the faster-increment group and 78 of 1399 (5.6%) in the slower-increment group (adjusted risk ratio, 0.88; 95% CI, 0.68 to 1.16). CONCLUSIONS: There was no significant difference in survival without moderate or severe neurodevelopmental disability at 24 months in very preterm or very-low-birth-weight infants with a strategy of advancing milk feeding volumes in daily increments of 30 ml per kilogram as compared with 18 ml per kilogram. (Funded by the Health Technology Assessment Programme of the National Institute for Health Research; SIFT Current Controlled Trials number, ISRCTN76463425.).

Improved growth of extremely and very preterm babies: Evaluation of a quality-of-care initiative.

AIM: To measure growth outcomes in preterm infants after introduction of a nutritional care bundle. METHODS: A total of 509 infants of less than 32 weeks' gestation in a level III neonatal intensive care unit in the UK were studied until they were discharged home. Growth and feeding data were extracted from a prospective data registry for 18 months before and after the intervention. The intervention consisted of earlier routine bovine-derived multi-component fortification once the infant has reached 120ml/kg/day of enteral feed from the first day of life and an exclusive human milk diet with routine bovine-derived multi-component fortification of 120 mL/kg/day. RESULTS: After the intervention, growth velocity between birth and 28 days increased from 9.7 ± 4.1 to 12.2 ± 4.6 g/kg/day (mean ± standard deviation), and weight z score change decreased from -1.06 ± 0.56 to -0.76 ± 0.59 (P < 0.00002). For the entire group, growth velocity by the discharge home time point increased by 1 g/kg/day. However, the growth velocity of infants who were discharged on an exclusive human milk diet increased the most, from 10.8 ± 2.2 to 13.0 ± 2.8 g/kg/day (P < 0.00001), eliminating the difference seen between these infants and those discharged on infant formula before the intervention. CONCLUSION: The introduction of a simple nutritional package improved weight gain, particularly in infants fed exclusive human milk at discharge.

Neonatal autonomic function after pregnancy complications and early cardiovascular development.

BACKGROUND: Heart rate variability (HRV) has emerged as a predictor of later cardiac risk. This study tested whether pregnancy complications that may have long-term offspring cardiac sequelae are associated with differences in HRV at birth, and whether these HRV differences identify abnormal cardiovascular development in the postnatal period. METHODS: Ninety-eight sleeping neonates had 5-min electrocardiogram recordings at birth. Standard time and frequency domain parameters were calculated and related to cardiovascular measures at birth and 3 months of age. RESULTS: Increasing prematurity, but not maternal hypertension or growth restriction, was associated with decreased HRV at birth, as demonstrated by a lower root mean square of the difference between adjacent NN intervals (rMSSD) and low (LF) and high-frequency power (HF), with decreasing gestational age (p < 0.001, p = 0.009 and p = 0.007, respectively). We also demonstrated a relative imbalance between sympathetic and parasympathetic tone, compared to the term infants. However, differences in autonomic function did not predict cardiovascular measures at either time point. CONCLUSIONS: Altered cardiac autonomic function at birth relates to prematurity rather than other pregnancy complications and does not predict cardiovascular developmental patterns during the first 3 months post birth. Long-term studies will be needed to understand the relevance to cardiovascular risk.

Disproportionate cardiac hypertrophy during early postnatal development in infants born preterm.

BackgroundAdults born very preterm have increased cardiac mass and reduced function. We investigated whether a hypertrophic phenomenon occurs in later preterm infants and when this occurs during early development.MethodsCardiac ultrasound was performed on 392 infants (33% preterm at mean gestation 34±2 weeks). Scans were performed during fetal development in 137, at birth and 3 months of postnatal age in 200, and during both fetal and postnatal development in 55. Cardiac morphology and function was quantified and computational models created to identify geometric changes.ResultsAt birth, preterm offspring had reduced cardiac mass and volume relative to body size with a more globular heart. By 3 months, ventricular shape had normalized but both left and right ventricular mass relative to body size were significantly higher than expected for postmenstrual age (left 57.8±41.9 vs. 27.3±29.4%, P<0.001; right 39.3±38.1 vs. 16.6±40.8, P=0.002). Greater changes were associated with lower gestational age at birth (left P<0.001; right P=0.001).ConclusionPreterm offspring, including those born in late gestation, have a disproportionate increase in ventricular mass from birth up to 3 months of postnatal age. These differences were not present before birth. Early postnatal development may provide a window for interventions relevant to long-term cardiovascular health.

The Speed of Increasing milk Feeds: a randomised controlled trial.

BACKGROUND: In the UK, 1-2% of infants are born very preterm (<32 weeks of gestation) or have very low birth weight (<1500 g). Very preterm infants are initially unable to be fed nutritional volumes of milk and therefore require intravenous nutrition. Milk feeding strategies influence several long and short term health outcomes including growth, survival, infection (associated with intravenous nutrition) and necrotising enterocolitis (NEC); with both infection and NEC being key predictive factors of long term disability. Currently there is no consistent strategy for feeding preterm infants across the UK. The SIFT trial will test two speeds of increasing milk feeds with the primary aim of determining effects on survival without moderate or severe neurodevelopmental disability at 24 months of age, corrected for prematurity. The trial will also examine many secondary outcomes including infection, NEC, time taken to reach full feeds and growth. METHODS/DESIGN: Two thousand eight hundred very preterm or very low birth weight infants will be recruited from approximately 30 hospitals across the UK to a randomised controlled trial. Infants with severe congenital anomaly or no realistic chance of survival will be excluded. Infants will be randomly allocated to either a faster (30 ml/kg/day) or slower (18 ml/kg/day) rate of increase in milk feeds. Data will be collected during the neonatal hospital stay on weight, infection rates, episodes of NEC, length of stay and time to reach full milk feeds. Long term health outcomes comprising vision, hearing, motor and cognitive impairment will be assessed at 24 months of age (corrected for prematurity) using a parent report questionnaire. DISCUSSION: Extensive searches have found no active or proposed studies investigating the rate of increasing milk feeds. The results of this trial will have importance for optimising incremental milk feeding for very preterm and/or very low birth weight infants. No additional resources will be required to implement an optimal feeding strategy, and therefore if successful, the trial results could rapidly be adopted across the NHS at low cost. TRIAL REGISTRATION: ISRCTN Registry; ISRCTN76463425 on 5 March, 2013.

Right ventricular systolic dysfunction in young adults born preterm.

BACKGROUND: Young adults born preterm have distinct differences in left ventricular mass, function, and geometry. Animal studies suggest that cardiomyocyte changes are evident in both ventricles after preterm birth; therefore, we investigated whether these young adults also have differences in their right ventricular structure and function. METHODS AND RESULTS: We studied 102 preterm-born young adults followed up prospectively since birth and 132 term-born control subjects born to uncomplicated pregnancies. We quantified right ventricular structure and function by cardiovascular magnetic resonance on a 1.5-T Siemens scanner using Argus and TomTec postprocessing software. Preterm birth was associated with a small right ventricle (end diastolic volume, 79.8±13.2 versus 88.5±11.8 mL/m(2); P<0.001) but greater right ventricular mass (24.5±3.5 versus 20.4±3.4 g/m2; P<0.001) compared with term-born controls, with the severity of differences proportional to gestational age (r=-0.47, P<0.001). Differences in right ventricular mass and function were proportionally greater than previously reported for the left ventricle. This was most apparent for systolic function; young adults born preterm had significantly lower right ventricular ejection fraction (57±8% versus 60±5%; P=0.006). Indeed, 21% had values below the lower limit observed in the term-born adults and 6% had mild systolic dysfunction (<45%). Postnatal ventilation accounted for some of the variation in mass but not function. CONCLUSIONS: Preterm birth is associated with global myocardial structural and functional differences in adult life, including smaller right ventricular size and greater mass. The changes are greater in the right ventricle than previously observed in the left ventricle, with potentially clinically significant impairment in right ventricular systolic function.

Preterm heart in adult life: cardiovascular magnetic resonance reveals distinct differences in left ventricular mass, geometry, and function.

BACKGROUND: Preterm birth leads to an early switch from fetal to postnatal circulation before completion of left ventricular in utero development. In animal studies, this results in an adversely remodeled left ventricle. We determined whether preterm birth is associated with a distinct left ventricular structure and function in humans. METHODS AND RESULTS: A total of 234 individuals 20 to 39 years of age underwent cardiovascular magnetic resonance. One hundred two had been followed prospectively since preterm birth (gestational age=30.3±2.5 week; birth weight=1.3±0.3 kg), and 132 were born at term to uncomplicated pregnancies. Longitudinal and short-axis cine images were used to quantify left ventricular mass, 3-dimensional geometric variation by creation of a unique computational cardiac atlas, and myocardial function. We then determined whether perinatal factors modify these left ventricular parameters. Individuals born preterm had increased left ventricular mass (66.5±10.9 versus 55.4±11.4 g/m(2); P<0.001) with greater prematurity associated with greater mass (r = -0.22, P=0.03). Preterm-born individuals had short left ventricles with small internal diameters and a displaced apex. Ejection fraction was preserved (P>0.99), but both longitudinal systolic (peak strain, strain rate, and velocity, P<0.001) and diastolic (peak strain rate and velocity, P<0.001) function and rotational (apical and basal peak systolic rotation rate, P =0.05 and P =0.006; net twist angle, P=0.02) movement were significantly reduced. A diagnosis of preeclampsia during the pregnancy was associated with further reductions in longitudinal peak systolic strain in the offspring (P=0.02, n=29). CONCLUSIONS: Individuals born preterm have increased left ventricular mass in adult life. Furthermore, they exhibit a unique 3-dimensional left ventricular geometry and significant reductions in systolic and diastolic functional parameters. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01487824.

The role of breast milk fortifier in the post-discharge nutrition of preterm infants.

Infants born prematurely are often discharged from hospital before 37 weeks post-menstrual age. While breastfeeding will meet all the nutritional requirements of full-term infants, these preterm infants may need enhanced levels of protein, minerals and possibly energy to ensure optimum growth, bone mineralisation and neurological development. To meet these additional nutrient needs in the neonatal unit, it is currently recommended that multinutrient breast milk fortifier is added to maternal breast milk. There may also be benefits in continuing to provide fortified milk after discharge, potentially including improved growth and preserving breastfeeding, and this is increasingly becoming a recognised practice in some neonatal units. This article presents the discussion and consensus of a multidisciplinary panel of neonatologists, neonatal dietitians, a GP and a neonatal outreach sister. The aim is to develop guidance on providing safe and effective nutritional supplementation for preterm infants after discharge in order to maintain optimal growth. This guidance is aimed at community healthcare staff and is based on the limited evidence available, using shared best practice and expertise.

Impaired myocardial reserve underlies reduced exercise capacity and heart rate recovery in preterm-born young adults.

AIMS: We tested the hypothesis that the known reduction in myocardial functional reserve in preterm-born young adults is an independent predictor of exercise capacity (peak VO2) and heart rate recovery (HRR). METHODS AND RESULTS: We recruited 101 normotensive young adults (n = 47 born preterm; 32.8 ± 3.2 weeks' gestation and n = 54 term-born controls). Peak VO2 was determined by cardiopulmonary exercise testing (CPET), and lung function assessed using spirometry. Percentage predicted values were then calculated. HRR was defined as the decrease from peak HR to 1 min (HRR1) and 2 min of recovery (HRR2). Four-chamber echocardiography views were acquired at rest and exercise at 40% and 60% of CPET peak power. Change in left ventricular ejection fraction from rest to each work intensity was calculated (EFΔ40% and EFΔ60%) to estimate myocardial functional reserve. Peak VO2 and per cent of predicted peak VO2 were lower in preterm-born young adults compared with controls (33.6 ± 8.6 vs. 40.1 ± 9.0 mL/kg/min, P = 0.003 and 94% ± 20% vs. 108% ± 25%, P = 0.001). HRR1 was similar between groups. HRR2 decreased less in preterm-born young adults compared with controls (-36 ± 13 vs. -43 ± 11 b.p.m., P = 0.039). In young adults born preterm, but not in controls, EFΔ40% and EFΔ60% correlated with per cent of predicted peak VO2 (r2 = 0.430, P = 0.015 and r2 = 0.345, P = 0.021). Similarly, EFΔ60% correlated with HRR1 and HRR2 only in those born preterm (r2 = 0.611, P = 0.002 and r2 = 0.663, P = 0.001). CONCLUSIONS: Impaired myocardial functional reserve underlies reductions in peak VO2 and HRR in young adults born moderately preterm. Peak VO2 and HRR may aid risk stratification and treatment monitoring in this population.

Adiposity is not altered in preterm infants fed with a nutrient-enriched formula after hospital discharge.

To determine whether adiposity was altered, body size (weight, length) and composition, determined by dual energy x-ray absorptiometry, were examined in preterm infants fed with a nutrient enriched (A, n=56), a term infant (B, n=57) or the nutrient enriched (discharge and term) plus the term formula (term and 6 mo; C, n=26), and a group of breast-fed preterm infants (D, n=25) at hospital discharge, 3, 6, and 12 mo corrected age. The results were analyzed using standard statistics. One hundred sixty-four infants (birth weight=1406+/-248 g, GA=31+/-1.7 wk) were studied. All infants underwent "catch-up," but weight and length were greater in infants in group A compared with groups B, C, or D. More rapid and complete "catch-up" was paralleled by increased total nonfat and fat mass (g) but not percentage of fat mass. Changes in fat mass (g) were primarily explained by increased fat accretion on the legs. More rapid and complete "catch-up" growth, therefore, reflected increased nonfat and peripheral fat mass. These data do not support the hypothesis of increased or central adiposity in infants fed a nutrient-enriched formula after hospital discharge.

Prenatal and Postnatal Cardiac Development in Offspring of Hypertensive Pregnancies.

Background Pregnancy complications such as preterm birth and fetal growth restriction are associated with altered prenatal and postnatal cardiac development. We studied whether there were changes related specifically to pregnancy hypertension. Methods and Results Left and right ventricular volumes, mass, and function were assessed at birth and 3 months of age by echocardiography in 134 term-born infants. Fifty-four had been born to mothers who had normotensive pregnancy and 80 had a diagnosis of preeclampsia or pregnancy-induced hypertension. Differences between groups were interpreted, taking into account severity of pregnancy disorder, sex, body size, and blood pressure. Left and right ventricular mass indexed to body surface area (LVMI and RVMI) were similar in both groups at birth (LVMI 20.9±3.7 versus 20.6±4.0 g/m2, P=0.64, RVMI 17.5±3.7 versus 18.1±4.7 g/m2, P=0.57). However, right ventricular end diastolic volume index was significantly smaller in those born to hypertensive pregnancy (16.8±5.3 versus 12.7±4.7 mL/m2, P=0.001), persisting at 3 months of age (16.4±3.2 versus 14.4±4.8 mL/m2, P=0.04). By 3 months of age these infants also had significantly greater LVMI and RVMI (LVMI 24.9±4.6 versus 26.8±4.9 g/m2, P=0.04; RVMI 17.1±4.2 versus 21.1±3.9 g/m2, P<0.001). Differences in RVMI and right ventricular end diastolic volume index at 3 months, but not left ventricular measures, correlated with severity of the hypertensive disorder. No differences in systolic or diastolic function were evident. Conclusions Infants born at term to a hypertensive pregnancy have evidence of both prenatal and postnatal differences in cardiac development, with right ventricular changes proportional to the severity of the pregnancy disorder. Whether differences persist long term as well as their underlying cause and relationship to increased cardiovascular risk requires further study.

Economic evaluation alongside the Speed of Increasing milk Feeds Trial (SIFT).

OBJECTIVE: To evaluate the cost-effectiveness of two rates of enteral feed advancement (18 vs 30 mL/kg/day) in very preterm and very low birth weight infants. DESIGN: Within-trial economic evaluation alongside a multicentre, two-arm parallel group, randomised controlled trial (Speed of Increasing milk Feeds Trial). SETTING: 55 UK neonatal units from May 2013 to June 2015. PATIENTS: Infants born <32 weeks' gestation or <1500 g, receiving less than 30 mL/kg/day of milk at trial enrolment. Infants with a known severe congenital anomaly, no realistic chance of survival, or unlikely to be traceable for follow-up, were ineligible. INTERVENTIONS: When clinicians were ready to start advancing feed volumes, infants were randomised to receive daily increments in feed volume of 30 mL/kg (intervention) or 18 mL/kg (control). MAIN OUTCOME MEASURE: Cost per additional survivor without moderate to severe neurodevelopmental disability at 24 months of age corrected for prematurity. RESULTS: Average costs per infant were slightly higher for faster feeds compared with slower feeds (mean difference £267, 95% CI -6928 to 8117). Fewer infants achieved the principal outcome of survival without moderate to severe neurodevelopmental disability at 24 months in the faster feeds arm (802/1224 vs 848/1246). The stochastic cost-effectiveness analysis showed a likelihood of worse outcomes for faster feeds compared with slower feeds. CONCLUSIONS: The stochastic cost-effectiveness analysis shows faster feeds are broadly equivalent on cost grounds. However, in terms of outcomes at 24 months age (corrected for prematurity), faster feeds are harmful. Faster feeds should not be recommended on either cost or effectiveness grounds to achieve the primary outcome.

Two speeds of increasing milk feeds for very preterm or very low-birthweight infants: the SIFT RCT.

BACKGROUND: Observational data suggest that slowly advancing enteral feeds in preterm infants may reduce necrotising enterocolitis but increase late-onset sepsis. The Speed of Increasing milk Feeds Trial (SIFT) compared two rates of feed advancement. OBJECTIVE: To determine if faster (30 ml/kg/day) or slower (18 ml/kg/day) daily feed increments improve survival without moderate or severe disability and other morbidities in very preterm or very low-birthweight infants. DESIGN: This was a multicentre, two-arm, parallel-group, randomised controlled trial. Randomisation was via a web-hosted minimisation algorithm. It was not possible to safely and completely blind caregivers and parents. SETTING: The setting was 55 UK neonatal units, from May 2013 to June 2015. PARTICIPANTS: The participants were infants born at < 32 weeks' gestation or a weight of < 1500 g, who were receiving < 30 ml/kg/day of milk at trial enrolment. INTERVENTIONS: When clinicians were ready to start advancing feed volumes, the infant was randomised to receive daily feed increments of either 30 ml/kg/day or 18 ml/kg/day. In total, 1400 infants were allocated to fast feeds and 1404 infants were allocated to slow feeds. MAIN OUTCOME MEASURES: The primary outcome was survival without moderate or severe neurodevelopmental disability at 24 months of age, corrected for gestational age. The secondary outcomes were mortality; moderate or severe neurodevelopmental disability at 24 months corrected for gestational age; death before discharge home; microbiologically confirmed or clinically suspected late-onset sepsis; necrotising enterocolitis (Bell's stage 2 or 3); time taken to reach full milk feeds (tolerating 150 ml/kg/day for 3 consecutive days); growth from birth to discharge; duration of parenteral feeding; time in intensive care; duration of hospital stay; diagnosis of cerebral palsy by a doctor or other health professional; and individual components of the definition of moderate or severe neurodevelopmental disability. RESULTS: The results showed that survival without moderate or severe neurodevelopmental disability at 24 months occurred in 802 out of 1224 (65.5%) infants allocated to faster increments and 848 out of 1246 (68.1%) infants allocated to slower increments (adjusted risk ratio 0.96, 95% confidence interval 0.92 to 1.01). There was no significant difference between groups in the risk of the individual components of the primary outcome or in the important hospital outcomes: late-onset sepsis (adjusted risk ratio 0.96, 95% confidence interval 0.86 to 1.07) or necrotising enterocolitis (adjusted risk ratio 0.88, 95% confidence interval 0.68 to 1.16). Cost-consequence analysis showed that the faster feed increment rate was less costly but also less effective than the slower rate in terms of achieving the primary outcome, so was therefore found to not be cost-effective. Four unexpected serious adverse events were reported, two in each group. None was assessed as being causally related to the intervention. LIMITATIONS: The study could not be blinded, so care may have been affected by knowledge of allocation. Although well powered for comparisons of all infants, subgroup comparisons were underpowered. CONCLUSIONS: No clear advantage was identified for the important outcomes in very preterm or very low-birthweight infants when milk feeds were advanced in daily volume increments of 30 ml/kg/day or 18 ml/kg/day. In terms of future work, the interaction of different milk types with increments merits further examination, as may different increments in infants at the extremes of gestation or birthweight. TRIAL REGISTRATION: Current Controlled Trials ISRCTN76463425. FUNDING: This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 18. See the NIHR Journals Library website for further project information.

Some infants who are born early need to be fed through a tube into their stomach. A small volume of milk is given to begin with, which is gradually increased. To determine whether infants do better if they are fed faster or slower, this study compared increasing the milk feeds by 30 ml/kg/day with increasing the milk feeds by 18 ml/kg/day, aiming to get to full feeds (when other fluids are not needed) in 5 or 9 days. We compared results from the two groups at discharge from hospital and at 24 months of age, after correcting for prematurity. We also assessed the economic impact of the two daily feed increments, interviewed parents about taking part in multiple studies and tested methods for improving questionnaire returns. The faster-fed group reached full milk feeds sooner and needed less intravenous nutrition, and the proportion of infants developing bowel inflammation or bloodstream infection were similar. At 24 months of age, we found an unexpected increase in the risk of moderate or severe motor impairment in the faster-fed group, which is difficult to explain. We also saw that other types of disability were more frequent in the faster group, although this was not significantly different mathematically. This means that no clear advantage of increasing feeds at faster or slower rates was identified and health professionals will need to carefully consider how to increase feeds. After accepting the increased risk of disability, an economic evaluation showed that increasing milk feed volumes at a faster rate was not a cost-effective strategy. Interviews with parents showed that they valued opportunities for their infant to take part in studies, but this interaction is complex and difficult to remember at a stressful and confusing time and made worse by considering multiple studies. More questionnaires were returned when vouchers were given before rather than after receiving them.

ADEPT - Abnormal Doppler Enteral Prescription Trial.

BACKGROUND: Pregnancies complicated by abnormal umbilical artery Doppler blood flow patterns often result in the baby being born both preterm and growth-restricted. These babies are at high risk of milk intolerance and necrotising enterocolitis, as well as post-natal growth failure, and there is no clinical consensus about how best to feed them. Policies of both early milk feeding and late milk feeding are widely used. This randomised controlled trial aims to determine whether a policy of early initiation of milk feeds is beneficial compared with late initiation. Optimising neonatal feeding for this group of babies may have long-term health implications and if either of these policies is shown to be beneficial it can be immediately adopted into clinical practice. METHODS AND DESIGN: Babies with gestational age below 35 weeks, and with birth weight below 10th centile for gestational age, will be randomly allocated to an "early" or "late" enteral feeding regimen, commencing milk feeds on day 2 and day 6 after birth, respectively. Feeds will be gradually increased over 9-13 days (depending on gestational age) using a schedule derived from those used in hospitals in the Eastern and South Western Regions of England, based on surveys of feeding practice. Primary outcome measures are time to establish full enteral feeding and necrotising enterocolitis; secondary outcomes include sepsis and growth. The target sample size is 400 babies. This sample size is large enough to detect a clinically meaningful difference of 3 days in time to establish full enteral feeds between the two feeding policies, with 90% power and a 5% 2-sided significance level. Initial recruitment period was 24 months, subsequently extended to 38 months. DISCUSSION: There is limited evidence from randomised controlled trials on which to base decisions regarding feeding policy in high risk preterm infants. This multicentre trial will help to guide clinical practice and may also provide pointers for future research. TRIAL REGISTRATION: Current Controlled Trials ISRCTN: 87351483.

Assessment of Signal Processing Methods for Measuring the Respiratory Rate in the Neonatal Intensive Care Unit.

Knowledge of the pathological instabilities in the breathing pattern can provide valuable insights into the cardiorespiratory status of the critically-ill infant as well as their maturation level. This paper is concerned with the measurement of respiratory rate in premature infants. We compare the rates estimated from the chest impedance pneumogram, the ECG-derived respiratory rhythms, and the PPG-derived respiratory rhythms against those measured in the reference standard of breath detection provided by attending clinical staff during 165 manual breath counts. We demonstrate that accurate RR estimates can be produced from all sources for RR in the 40-80 bpm (breaths per min) range. We also conclude that the use of indirect methods based on the ECG or the PPG poses a fundamental challenge in this population due to their poor behavior at fast breathing rates (upward of 80 bpm).

Cardio-respiratory signal extraction from video camera data for continuous non-contact vital sign monitoring using deep learning.

Non-contact vital sign monitoring enables the estimation of vital signs, such as heart rate, respiratory rate and oxygen saturation (SpO2), by measuring subtle color changes on the skin surface using a video camera. For patients in a hospital ward, the main challenges in the development of continuous and robust non-contact monitoring techniques are the identification of time periods and the segmentation of skin regions of interest (ROIs) from which vital signs can be estimated. We propose a deep learning framework to tackle these challenges. APPROACH: This paper presents two convolutional neural network (CNN) models. The first network was designed for detecting the presence of a patient and segmenting the patient's skin area. The second network combined the output from the first network with optical flow for identifying time periods of clinical intervention so that these periods can be excluded from the estimation of vital signs. Both networks were trained using video recordings from a clinical study involving 15 pre-term infants conducted in the high dependency area of the neonatal intensive care unit (NICU) of the John Radcliffe Hospital in Oxford, UK. MAIN RESULTS: Our proposed methods achieved an accuracy of 98.8% for patient detection, a mean intersection-over-union (IOU) score of 88.6% for skin segmentation and an accuracy of 94.5% for clinical intervention detection using two-fold cross validation. Our deep learning models produced accurate results and were robust to different skin tones, changes in light conditions, pose variations and different clinical interventions by medical staff and family visitors. SIGNIFICANCE: Our approach allows cardio-respiratory signals to be continuously derived from the patient's skin during which the patient is present and no clinical intervention is undertaken.

Non-contact physiological monitoring of preterm infants in the Neonatal Intensive Care Unit.

The implementation of video-based non-contact technologies to monitor the vital signs of preterm infants in the hospital presents several challenges, such as the detection of the presence or the absence of a patient in the video frame, robustness to changes in lighting conditions, automated identification of suitable time periods and regions of interest from which vital signs can be estimated. We carried out a clinical study to evaluate the accuracy and the proportion of time that heart rate and respiratory rate can be estimated from preterm infants using only a video camera in a clinical environment, without interfering with regular patient care. A total of 426.6 h of video and reference vital signs were recorded for 90 sessions from 30 preterm infants in the Neonatal Intensive Care Unit (NICU) of the John Radcliffe Hospital in Oxford. Each preterm infant was recorded under regular ambient light during daytime for up to four consecutive days. We developed multi-task deep learning algorithms to automatically segment skin areas and to estimate vital signs only when the infant was present in the field of view of the video camera and no clinical interventions were undertaken. We propose signal quality assessment algorithms for both heart rate and respiratory rate to discriminate between clinically acceptable and noisy signals. The mean absolute error between the reference and camera-derived heart rates was 2.3 beats/min for over 76% of the time for which the reference and camera data were valid. The mean absolute error between the reference and camera-derived respiratory rate was 3.5 breaths/min for over 82% of the time. Accurate estimates of heart rate and respiratory rate could be derived for at least 90% of the time, if gaps of up to 30 seconds with no estimates were allowed.

Physiological Stress Elicits Impaired Left Ventricular Function in Preterm-Born Adults.

BACKGROUND: Experimental and clinical studies show that prematurity leads to altered left ventricular (LV) structure and function with preserved resting LV ejection fraction (EF). Large-scale epidemiological data now links prematurity to increased early heart failure risk. OBJECTIVES: The authors performed echocardiographic imaging at prescribed exercise intensities to determine whether preterm-born adults have impaired LV functional response to physical exercise. METHODS: We recruited 101 normotensive young adults born preterm (n = 47; mean gestational age 32.8 ± 3.2 weeks) and term (n = 54) for detailed cardiovascular phenotyping. Full clinical resting and exercise stress echocardiograms were performed, with apical 4-chamber views collected while exercising at 40%, 60%, and 80% of peak exercise capacity, determined by maximal cardiopulmonary exercise testing. RESULTS: Preterm-born individuals had greater LV mass (p = 0.015) with lower peak systolic longitudinal strain (p = 0.038) and similar EF to term-born control subjects at rest (p = 0.62). However, by 60% exercise intensity, EF was 6.7% lower in preterm subjects (71.9 ± 8.7% vs 78.6 ± 5.4%; p = 0.004) and further declined to 7.3% below the term-born group at 80% exercise intensity (69.8 ± 6.4% vs 77.1 ± 6.3%; p = 0.004). Submaximal cardiac output reserve was 56% lower in preterm-born subjects versus term-born control subjects at 40% of peak exercise capacity (729 ± 1,162 ml/min/m2 vs. 1,669 ± 937 ml/min/m2; p = 0.021). LV length and resting peak systolic longitudinal strain predicted EF increase from rest to 60% exercise intensity in the preterm group (r = 0.68, p = 0.009 and r = 0.56, p = 0.031, respectively). CONCLUSIONS: Preterm-born young adults had impaired LV response to physiological stress when subjected to physical exercise, which suggested a reduced myocardial functional reserve that might help explain their increased risk of early heart failure. (Young Adult Cardiovascular Health sTudy [YACHT]; NCT02103231).

Monitoring the Postnatal Growth of Preterm Infants: A Paradigm Change.

There is no consensus regarding how the growth of preterm infants should be monitored or what constitutes their ideal pattern of growth, especially after term-corrected age. The concept that the growth of preterm infants should match that of healthy fetuses is not substantiated by data and, in practice, is seldom attained, particularly for very preterm infants. Hence, by hospital discharge, many preterm infants are classified as postnatal growth-restricted. In a recent systematic review, 61 longitudinal reference charts were identified, most with considerable limitations in the quality of gestational age estimation, anthropometric measures, feeding regimens, and how morbidities were described. We suggest that the correct comparator for assessing the growth of preterm infants, especially those who are moderately or late preterm, is a cohort of preterm newborns (not fetuses or term infants) with an uncomplicated intrauterine life and low neonatal and infant morbidity. Such growth monitoring should be comprehensive, as recommended for term infants, and should include assessments of postnatal length, head circumference, weight/length ratio, and, if possible, fat and fat-free mass. Preterm postnatal growth standards meeting these criteria are now available and may be used to assess preterm infants until 64 weeks' postmenstrual age (6 months' corrected age), the time at which they overlap, without the need for any adjustment, with the World Health Organization Child Growth Standards for term newborns. Despite remaining nutritional gaps, 90% of preterm newborns (ie, moderate to late preterm infants) can be monitored by using the International Fetal and Newborn Growth Consortium for the 21st Century Preterm Postnatal Growth Standards from birth until life at home.

Elevated blood pressure in preterm-born offspring associates with a distinct antiangiogenic state and microvascular abnormalities in adult life.

Preterm-born individuals have elevated blood pressure. We tested the hypothesis that this associates with an enhanced antiangiogenic circulating profile and that this association is mediated by variations in capillary density. We studied 204 adults aged 25 years (range, 20-30 years), of which 102 had been followed up prospectively since very preterm birth (mean gestational age, 30.3±2.5 weeks) and 102 were born term to uncomplicated pregnancies. A panel of circulating biomarkers, including soluble endoglin and soluble fms-like tyrosine kinase-1, were compared between groups and related to perinatal history and adult cardiovascular risk. Associations with cardiovascular phenotype were studied in 90 individuals who had undergone detailed assessment of microvascular, macrovascular, and cardiac structure and function. Preterm-born individuals had elevations in soluble endoglin (5.64±1.03 versus 4.06±0.85 ng/mL; P<0.001) and soluble fms-like tyrosine kinase-1 (88.1±19.0 versus 73.0±15.3 pg/mL; P<0.001) compared with term-born individuals, proportional to elevations in resting and ambulatory blood pressure, as well as degree of prematurity (P<0.05). Maternal hypertensive pregnancy disorder was associated with additional increases in soluble fms-like tyrosine kinase-1 (P=0.002). Other circulating biomarkers, including those of inflammation and endothelial activation, were not related to blood pressure. There was a specific graded association between soluble endoglin and degree of functional and structural capillary rarefaction (P=0.002 and P<0.001), and in multivariable analysis, there were capillary density-mediated associations between soluble endoglin and blood pressure. Preterm-born individuals exhibit an enhanced antiangiogenic state in adult life that is specifically related to elevations in blood pressure. The association seems to be mediated through capillary rarefaction and is independent of other cardiovascular structural and functional differences in the offspring.