Anatomically Realistic Neonatal Heart Model for Use in Neonatal Patient Simulators.

Neonatal patient simulators (NPS) are artificial patient surrogates used in the context of medical simulation training. Neonatologists and nursing staff practice clinical interventions such as chest compressions to ensure patient survival in the case of bradycardia or cardiac arrest. The simulators used currently are of low physical fidelity and therefore cannot provide qualitative insight into the procedure of chest compressions. The embedding of an anatomically realistic heart model in future simulators enables the detection of cardiac output generated during chest compressions; this can provide clinicians with an output parameter, which can deepen the understanding of the effect of the compressions in relation to the amount of blood flow generated. Before this monitoring can be achieved, an anatomically realistic heart model must be created containing: two atria, two ventricles, four heart valves, pulmonary veins and arteries, and systemic veins and arteries. This protocol describes the procedure for creating such a functional artificial neonatal heart model by utilizing a combination of magnetic resonance imaging (MRI), 3D printing, and casting in the form of cold injection molding. Using this method with flexible 3D printed inner molds in the injection molding process, an anatomically realistic heart model can be obtained.

Changes in autonomic regulation due to Kangaroo care remain unaffected by using a swaddling device.

AIM: To investigate the effects of a swaddling device known as the Hugsy (Hugsy, Eindhoven, the Netherlands) towards improving autonomic regulation. This device can be used both in the incubator and during Kangaroo care to absorb parental scent and warmth. After Kangaroo care, these stimuli can continue to be experienced by infants, while in the incubator. Additionally, a pre-recorded heartbeat sound can be played. METHOD: Autonomic regulation was compared in preterm infants before, during and after Kangaroo care with and without the use of a swaddling device in a within-subject study carried out in a level III neonatal intensive care unit. Descriptive statistics and effect sizes were calculated corresponding to changes in heart rate, respiratory rate, oxygen saturation, temperature and heart rate variability on intervention versus control days. RESULTS: In this study of 20 infants with a median (interquartile range) gestational age of 28.4 (27-29.9) weeks, Kangaroo care was associated with a decrease in heart rate, respiratory rate and heart rate variability on both intervention and control days. There were no differences between intervention and control days. CONCLUSION: The use of an alternative swaddling device aimed at facilitating Kangaroo care did not enhance autonomic regulation, as measured by vital signs and heart rate variability.

An innovative design for cardiopulmonary resuscitation manikins based on a human-like thorax and embedded flow sensors.

Cardiopulmonary resuscitation manikins are used for training personnel in performing cardiopulmonary resuscitation. State-of-the-art cardiopulmonary resuscitation manikins are still anatomically and physiologically low-fidelity designs. The aim of this research was to design a manikin that offers high anatomical and physiological fidelity and has a cardiac and respiratory system along with integrated flow sensors to monitor cardiac output and air displacement in response to cardiopulmonary resuscitation. This manikin was designed in accordance with anatomical dimensions using a polyoxymethylene rib cage connected to a vertebral column from an anatomical female model. The respiratory system was composed of silicon-coated memory foam mimicking lungs, a polyvinylchloride bronchus and a latex trachea. The cardiovascular system was composed of two sets of latex tubing representing the pulmonary and aortic arteries which were connected to latex balloons mimicking the ventricles and lumped abdominal volumes, respectively. These balloons were filled with Life/form simulation blood and placed inside polyether foam. The respiratory and cardiovascular systems were equipped with flow sensors to gather data in response to chest compressions. Three non-medical professionals performed chest compressions on this manikin yielding data corresponding to force-displacement while the flow sensors provided feedback. The force-displacement tests on this manikin show a desirable nonlinear behaviour mimicking chest compressions during cardiopulmonary resuscitation in humans. In addition, the flow sensors provide valuable data on the internal effects of cardiopulmonary resuscitation. In conclusion, scientifically designed and anatomically high-fidelity designs of cardiopulmonary resuscitation manikins that embed flow sensors can improve physiological fidelity and provide useful feedback data.

Antenatal mother-infant bonding scores are related to maternal reports of infant crying behaviour.

OBJECTIVE: To assess the relation between antenatal mother-infant bonding scores and maternal reports of infant crying behaviour. BACKGROUND: Crying is normal behaviour and it is important for parent-infant bonding. Even though bonding starts antenatally, the relation between antenatal bonding scores and infant crying behaviour has never been studied. METHOD: A secondary analysis was performed on data that were gathered in a large prospective study within our region. Bonding was assessed using an antenatal bonding questionnaire at 32 weeks gestational age. The crying behaviour of infants was assessed with three questions at six weeks postpartum. Crying was termed excessive (EC+) when mothers perceived the crying to be 'every day', 'often' or 'very often', and with 'crying episodes lasting more than 30 minutes'; in other words, when mothers scored high on all three questions. The relation between bonding and crying was examined using a multiple logistic regression analysis, including adjustment for relevant variables, especially maternal depression as measured with the Edinburgh Depression Scale. RESULTS: In total, 894 women were included of whom 47 reported EC+ infants (5.3%). Antenatal bonding scores were significantly related to the reporting of crying behaviour, even after adjustment for relevant variables (p = 0.02). Each extra point on the bonding scale reduced the EC+ risk with 14% (OR = 0.86, 95% CI [0.76-0.97]). CONCLUSION: Mothers with lower antenatal bonding scores were more likely to report an EC+ infant. Future research should further explore the concept of antenatal bonding, its relation with EC and risks associated with EC.

Features of Heart Rate Variability Capture Regulatory Changes During Kangaroo Care in Preterm Infants.

OBJECTIVE: To determine whether heart rate variability (HRV) can serve as a surrogate measure to track regulatory changes during kangaroo care, a period of parental coregulation distinct from regulation within the incubator. STUDY DESIGN: Nurses annotated the starting and ending times of kangaroo care for 3 months. The pre-kangaroo care, during-kangaroo care, and post-kangaroo care data were retrieved in infants with at least 10 accurately annotated kangaroo care sessions. Eight HRV features (5 in the time domain and 3 in the frequency domain) were used to visually and statistically compare the pre-kangaroo care and during-kangaroo care periods. Two of these features, capturing the percentage of heart rate decelerations and the extent of heart rate decelerations, were newly developed for preterm infants. RESULTS: A total of 191 kangaroo care sessions were investigated in 11 preterm infants. Despite clinically irrelevant changes in vital signs, 6 of the 8 HRV features (SD of normal-to-normal intervals, root mean square of the SD, percentage of consecutive normal-to-normal intervals that differ by >50 ms, SD of heart rate decelerations, high-frequency power, and low-frequency/high-frequency ratio) showed a visible and statistically significant difference (P <.01) between stable periods of kangaroo care and pre-kangaroo care. HRV was reduced during kangaroo care owing to a decrease in the extent of transient heart rate decelerations. CONCLUSION: HRV-based features may be clinically useful for capturing the dynamic changes in autonomic regulation in response to kangaroo care and other changes in environment and state.

A Review of Wearable Sensor Systems for Monitoring Body Movements of Neonates.

Characteristics of physical movements are indicative of infants' neuro-motor development and brain dysfunction. For instance, infant seizure, a clinical signal of brain dysfunction, could be identified and predicted by monitoring its physical movements. With the advance of wearable sensor technology, including the miniaturization of sensors, and the increasing broad application of micro- and nanotechnology, and smart fabrics in wearable sensor systems, it is now possible to collect, store, and process multimodal signal data of infant movements in a more efficient, more comfortable, and non-intrusive way. This review aims to depict the state-of-the-art of wearable sensor systems for infant movement monitoring. We also discuss its clinical significance and the aspect of system design.

Unobtrusive Monitoring of Neonatal Brain Temperature Using a Zero-Heat-Flux Sensor Matrix.

The temperature of preterm neonates must be maintained within a narrow window to ensure their survival. Continuously measuring their core temperature provides an optimal means of monitoring their thermoregulation and their response to environmental changes. However, existing methods of measuring core temperature can be very obtrusive, such as rectal probes, or inaccurate/lagging, such as skin temperature sensors and spot-checks using tympanic temperature sensors. This study investigates an unobtrusive method of measuring brain temperature continuously using an embedded zero-heat-flux (ZHF) sensor matrix placed under the head of the neonate. The measured temperature profile is used to segment areas of motion and incorrect positioning, where the neonate's head is not above the sensors. We compare our measurements during low motion/stable periods to esophageal temperatures for 12 preterm neonates, measured for an average of 5 h per neonate. The method we propose shows good correlation with the reference temperature for most of the neonates. The unobtrusive embedding of the matrix in the neonate's environment poses no harm or disturbance to the care work-flow, while measuring core temperature. To address the effect of motion on the ZHF measurements in the current embodiment, we recommend a more ergonomic embedding ensuring the sensors are continuously placed under the neonate's head.

Non-contact heart rate monitoring utilizing camera photoplethysmography in the neonatal intensive care unit - a pilot study.

BACKGROUND: Presently the heart rate is monitored in the Neonatal Intensive Care Unit with contact sensors: electrocardiogram or pulse oximetry. These techniques can cause injuries and infections, particularly in very premature infants with fragile skin. Camera based plethysmography was recently demonstrated in adults as a contactless method to determine heart rate. AIM: To investigate the feasibility of this technique for NICU patients and identify challenging conditions. STUDY DESIGN AND PARTICIPANTS: Video recordings using only ambient light were made of 19 infants at two NICUs in California and The Netherlands. Heart rate can be derived from these recordings because each cardiovascular pulse wave induces minute pulsatile skin color changes, invisible to the eye but measurable with a camera. RESULTS: In all infants the heart beat induced photoplethysmographic signal was strong enough to be measured. Low ambient light level and infant motion prevented successful measurement from time to time. CONCLUSIONS: Contactless heart rate monitoring by means of a camera using ambient light was demonstrated for the first time in the NICU population and appears feasible. Better hardware and improved algorithms are required to increase robustness.

Multi-channel amplitude-integrated EEG characteristics in preterm infants with a normal neurodevelopment at two years of corrected age.

AIM: To analyze quantitatively multi-channel amplitude-integrated EEG (aEEG) characteristics and assess regional differences. METHODS: We investigated 40 preterm infants (postmenstrual age, PMA: range 27-37 weeks) with normal follow-up at 24 months of age, at a median postnatal age of 8 days using 4-h EEG recordings according to the international 10-20 system reduced montage. Nine (3 transverse and 6 longitudinal) channels were selected and converted to aEEG registrations. For each aEEG registration, lower margin amplitude (LMA), upper margin amplitude (UMA) and bandwidth (UMA-LMA) were calculated. RESULTS: In all channels PMA and LMA showed strong positive correlations. Below 32 weeks of PMA, LMA was ≤5µV. Linear regression analysis showed a maximum LMA difference between channels of approximately 2 and 1µV at 27 and 37 weeks of PMA, respectively. The lowest are LMA values in the occipital channel and the highest values are in centro-occipital channels. In the frontal, centro-temporal and centro-occipital channels, UMA and bandwidth changed with PMA. No differences in LMA, UMA and bandwidth were found between hemispheres. Skewness of LMA values strongly correlated with PMA, positive skewness indicating an immature brain (PMA≤32 weeks) and negative skewness a maturing (PMA>32 weeks) brain. CONCLUSIONS: We detected symmetric increase of aEEG characteristics, indicating symmetric brain maturation of the left and right hemispheres. Our findings demonstrate the clinical potential of computer-assisted analyses of aEEG recordings in detecting maturational features which are not readily identified visually. This may provide an objective and reproducible method for assessing brain maturation and long-term prognosis.

Maturational changes in automated EEG spectral power analysis in preterm infants.

Our study aimed at automated power spectral analysis of the EEG in preterm infants to identify changes of spectral measures with maturation. Weekly (10-20 montage) 4-h EEG recordings were performed in 18 preterm infants with GA <32 wk and normal neurological follow-up at 2 y, resulting in 79 recordings studied from 27(+4) to 36(+3) wk of postmenstrual age (PMA, GA + postnatal age). Automated spectral analysis was performed on 4-h EEG recordings. The frequency spectrum was divided in delta 1 (0.5-1 Hz), delta 2 (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) band. Absolute and relative power of each frequency band and spectral edge frequency were calculated. Maturational changes in spectral measures were observed most clearly in the centrotemporal channels. With advancing PMA, absolute powers of delta 1 to 2 and theta decreased. With advancing PMA, relative power of delta 1 decreased and relative powers of alpha and beta increased, respectively. In conclusion, with maturation, spectral analysis of the EEG showed a significant shift from the lower to the higher frequencies. Computer analysis of EEG will allow an objective and reproducible analysis for long-term prognosis and/or stratification of clinical treatment.

Rhythm of Life Aid (ROLA): an integrated sensor system for supporting medical staff during cardiopulmonary resuscitation (CPR) of newborn infants.

During the stress of cardiopulmonary resuscitation (CPR), it is difficult to maintain the right rhythm and correct ratio of insufflations to chest compressions and to exert the compressions at a constant pressure. In this paper, we propose and demonstrate an integrated sensor system-the "Rhythm of Life Aid" (ROLA) to support medical staff during CPR of newborn infants. The design concept is based on interactive audio and visual feedback with consideration of functionalities and user friendliness. A prototype ROLA device is built, consisting of a transparent foil integrated with pressure sensor and electroluminescent foil actuators for indication of the exerted chest compression pressure, as well as an audio box to generate distinctive sounds as audio guidance for insufflations and compressions. To evaluate the performance of the ROLA device, a sensory mannequin and a dedicated software interface are implemented to give immediate feedback and record data for further processing. Tests of the ROLA prototype on the sensory mannequin by ten pairs of a doctor and a nurse at Máxima Medical Centre in Veldhoven, The Netherlands show that the use of ROLA device achieves a more constant rhythm and pressure of chest compressions during CPR of newborn infants.

Cerebral MRI abnormalities in a premature infant with later confirmed congenital central hypoventilation syndrome.

We present a premature infant with an inability to ventilate spontaneously during sleep periods. In addition, the patient showed general hypotonia. The child had a delayed passage of stool and increased anal muscle tone, indicating Hirschsprung's disease. The combination of these symptoms suggested congenital central hypoventilation syndrome, which was confirmed postmortem by DNA analysis showing a mutation in the PHOX2B gene. MRI of the brain showed damage to the white matter, including the internal capsula. This type of damage to the white matter has not been described before in a premature infant, who did not experience birth asphyxia.

Activation of the inflammatory reaction within minutes after birth in ventilated preterm lambs with neonatal respiratory distress syndrome.

To study the activation of the inflammatory reaction within minutes after birth, we measured parameters of inflammation before and immediately after birth. To assess whether respiratory distress syndrome (RDS) or birth itself initiates activation, we compared preterm ventilated lambs with term nonventilated lambs. Preterm lambs were delivered by cesarean section at 132 days gestational age (term 145 days) and were ventilated by conventional ventilation (n = 9). Before clamping the cord, 5, 10 and 15 min after birth, blood was sampled from umbilical catheters. Term lambs (n = 9) were born spontaneously after 140-145 days gestational age. Immediately after birth, a venous umbilical catheter was inserted. Blood was sampled before the first breath and 5, 10, 15 and 20 min after birth while the lamb was breathing spontaneously. Blood was analyzed for AP50 (complement activation), number of polymorphonuclear leukocytes (PMNs) and beta-glucuronidase (released from activated PMNs). In preterm lambs, we found a decreased number of PMNs and increased levels of beta-glucuronidase already at 5 min after birth. In the term lambs, we found only a short-term mild decrease in PMNs and short-term increase in beta-glucuronidase. We conclude that systemic activation of the inflammatory reaction can be found in ventilated preterm lambs with RDS within 5 min after birth. This very early activation is mild, transient and less pronounced in term-born spontaneously breathing lambs compared with preterm, ventilated lambs with RDS.

Antenatal glucocorticoids attenuate activation of the inflammatory reaction and clotting in preterm lambs.

Recently we have shown that activation of inflammatory reaction and clotting can be found immediately after delivery in preterm lambs ventilated for respiratory distress syndrome (RDS). To investigate whether antenatal glucocorticoids would attenuate postnatal activation of the inflammatory reaction and clotting, we studied ventilated preterm lambs delivered by cesarean section, 24 h after antenatal administration of betamethasone or placebo. Blood was sampled before clamping the cord, 5, 10, and 15 min after delivery, and 2-hourly afterwards. Blood was used to determine oxygenation index, alveolar - arterial partial O(2) difference (AaDO(2)), AP50 titer (see text), polymorphonuclear leukocytes (PMNs), beta-glucuronidase, thrombin inhibition, activated partial thromboplastin time, and clot lysis time. Bronchoalveolar lavage fluid was sampled before clamping the cord and 30 min and 1, 2, 4, 6 and 8 h after delivery and was analyzed for elastase, thrombin, and protein. After removal of the lungs, static compliance and water content of the lungs were determined. We found that betamethasone-treated lambs had lower oxygenation index and AaDO(2) than controls. At birth, PMN levels were higher, and the beta-glucuronidase level was lower after betamethasone treatment. PMNs and beta-glucuronidase did not change in betamethasone-treated lambs, in contrast to controls. Thrombin inhibition, activated partial thromboplastin time, and clot lysis time did not change in betamethasone-treated lambs, in contrast to controls. In both groups, elastase and protein levels in bronchoalveolar lavage fluid increased; the thrombin level increased in controls. The static compliance was better, and the water content of the lung was lower in the betamethasone-treated lambs. We conclude that early systemic activation of inflammatory reaction and clotting in preterm lambs with RDS are attenuated by antenatal betamethasone administration. Whether this is a direct effect of betamethasone on the inflammatory reaction or a result of a reduced ventilatory support because of less severe RDS after antenatal betamethasone treatment remains to be elucidated.