Sidarto Bambang Oetomo

Baroreceptor reflex sensitivity in human neonates: the effect of postmenstrual age

We performed a cross‐sectional study in human infants to determine if indices of R–R interval variability, systolic blood pressure (SBP) variability, and baroreceptor reflex sensitivity change with postmenstrual age (PMA: gestational age + postnatal age). The electrocardiogram, arterial SBP and respiration were recorded in clinically stable infants (PMA, 28–42 weeks) in the quiet sleep state in the first days after birth. (Cross‐)spectral analyses of R–R interval series and SBP series were performed to calculate the power of low‐frequency (LF, indicating baroreceptor reflex activity, 0.04–0.15 Hz) and high‐frequency (HF, indicating parasympathetic activity, individualized between the p‐10 and p‐90 values of respiratory frequency) fluctuations, and transfer function phase and gain. The mean R–R interval, and LF and HF spectral powers of R–R interval series increased with PMA. The mean SBP increased with PMA, but not the LF and HF spectral powers of SBP series. In the LF range, cross‐spectral analysis showed high coherence values (> 0.5) with a consistent negative phase shift between R–R interval and SBP, indicating a ∼3 s lag in R–R interval changes in relation to SBP. Baroreceptor reflex sensitivity, calculated from LF transfer gain, increased significantly with PMA, from 5 (preterm) to 15 ms mmHg−1 (term). Baroreceptor reflex sensitivity correlated significantly with the (LF and) HF spectral powers of R–R interval series, but not with the LF and HF spectral powers of SBP series. The principal conclusions are that baroreceptor reflex sensitivity and spectral power in R–R interval series increase in parallel with PMA, suggesting a progressive vagal maturation with PMA.

Smart Jacket Design for Neonatal Monitoring with Wearable Sensors

Critically ill new born babies admitted at the Neonatal Intensive Care Unit (NICU) are extremely tiny and vulnerable to external disturbance. Smart Jacket proposed in this paper is the vision of a wearable unobtrusive continuous monitoring system realized by body sensor networks (BSN) and wireless communication. The smart jacket aims for providing reliable health monitoring as well as a comfortable clinical environment for neonatal care and parent-child interaction. We present the first version of the neonatal jacket that enables ECG measurement by textile electrodes. We also explore a new solution for skin-contact challenges that textile electrodes pose. The jacket is expandable with new wearable technologies and has aesthetics that appeal to parents and medical staff. An iterative design process in close contact with the users and experts lead to a balanced integration of technology, user focus and aesthetics. We demonstrate the prototype and the experimental results obtained in clinical setting.

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.

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.

Monitoring body temperature of newborn infants at neonatal intensive care units using wearable sensors

Body temperature is one of the key parameters for health monitoring of premature infants at the neonatal intensive care unit (NICU). In this paper, we propose and demonstrate a design of non-invasive neonatal temperature monitoring with wearable sensors. A negative temperature coefficient (NTC) resistor is applied as the temperature sensor due to its accuracy and small size. Conductive textile wires are used to make the sensor integration compatible for a wearable non-invasive monitoring platform, such as a neonatal smart jacket. Location of the sensor, materials and appearance are designed to optimize the functionality, patient comfort and the possibilities for aesthetic features. A prototype belt is built of soft bamboo fabrics with NTC sensor integrated to demonstrate the temperature monitoring. Experimental results from the testing on neonates at NICU of Máxima Medical Center (MMC), Veldhoven, the Netherlands, show the accurate temperature monitoring by the prototype belt comparing with the standard patient monitor.

Sensor integration for perinatology research

The number of high-risk pregnancies and premature births is increasing due to the steadily higher age at which women get pregnant. The long-term quality of life of the neonates and their families depends increasingly critically on the ability to monitor the health status of mother and child accurately, continuously and unobtrusively throughout the perinatal period. Advances in sensor integration have enabled the creation of non-invasive solutions to improve the healthcare of the pregnant woman, and her child before, during and after delivery. In this paper, we present the design work of a smart jacket integrated with textile sensors for neonatal monitoring and software architecture of advanced sensor integration for delivery simulator. A balanced integration of technology, user focuses and design aspects is achieved. Prototypes are built for demonstrating the design concept and the experimental results are obtained in clinical settings.

Wireless transmission design for health monitoring at neonatal intensive care units

Health monitoring is crucial for the survival of the ill and fragile infants admitted at the neonatal intensive care unit (NICU) in a hospital. However, the adhesive electrodes and wires cause discomfort to the patients and hamper the parent-child interaction. In this paper, we propose the application of wireless transmission technology for neonatal monitoring at NICU. To demonstrate the design concept, a prototype wireless transmission system is built using BlueSMiRF and Arduino pro mini. Software is developed for ensure the correct data transmission, detection and display. The system is designed to be suitable for integration into a non-invasive monitoring platform such as a smart neonatal jacket. Experimental results show that the prototype system successfully transmits and receives data from multiple sensors within the range of 20 m.

A design of power supply for neonatal monitoring with wearable sensors

Continuous monitoring of health parameters is crucial for preterm new born babies admitted at the neonatal intensive care unit (NICU) in hospitals. The critically ill neonates are extremely tiny and vulnerable to external disturbance. In the context of ambient intelligence and smart environments, non-invasive health monitoring with wearable sensors is promising for the survival of these neonates and the quality of their life later on. A key question for health monitoring with wearable sensors is how to obtain reliable electrical power for the sensors, signal amplifiers, filters and transmitters. In this paper, we propose a design of wireless power supply based on the principle of inductive contactless energy transfer for use in NICU. The design process consists of scientific and user research, idea generation and selection, proof of technology, prototype implementation, and experimental validation. The proposed power supply satisfies the requirements of neonatal monitoring and provides continuous power when the neonate is inside the incubator or during Kangaroo mother care. A prototype is designed and implemented to demonstrate the performance of the power supply and the possibilities for aesthetic features. Experimental results show that the prototype transfers approximately 840 mW of power.

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 β-glucuronidase (released from activated PMNs). In preterm lambs, we found a decreased number of PMNs and increased levels of β-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 β-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.

Surfactant nebulization versus instillation during high frequency ventilation in surfactant-deficient rabbits

Surfactant nebulization improves lung function at low alveolar doses of surfactant. However, efficiency of nebulization is low, and lung deposition seems to depend on lung aeration. High frequency ventilation (HFV) has been shown to improve lung aeration. We hypothesize that the combination of HFV and surfactant nebulization may benefit lung deposition of surfactant and consequently, lung function. The aim of this study was to compare the effect of surfactant nebulization versus instillation during HFV on lung function, surfactant distribution, and cerebral blood flow. Therefore, severe respiratory failure was induced by lung lavages in 18 rabbits. HFV was applied: frequency = 8 Hz, mean airway pressure = 12 cm H2O, amplitude = 100%, fraction of inspired O2 = 1.0. Technetium-99m-labeled surfactant (Alveofact, 100 mg/kg of BW) was nebulized or instilled (n = 6 each). Six other rabbits did not receive surfactant (control, HFV only). We found that after instillation partial arterial O2 tension increased from 7.0 kPa (95% confidence interval, 6.3-8.0 kPa) to 34 kPa (16-51 kPa), and during nebulization from 7.0 kPa (6.0-9.0 kPa) to 46 kPa (27-58 kPa). Partial arterial CO2 tension decreased after instillation from 6.1 kPa (5.3-7.1 kPa) to 4.8 kPa (3.9-5.6 kPa), and during nebulization, after an initial rise, it decreased from 6.3 kPa (5.3-7.4 kPa) to 4.9 kPa (4.4-5.6 kPa). Both treatments resulted in nonuniform distribution. Surfactant deposition after nebulization was 9.8%. Instillation resulted in a drop of mean arterial blood pressure of 17% (8-31%), and an even more pronounced drop in cerebral blood flow of 39% (18-57%). Nebulization did not affect blood pressure. Cerebral blood flow decreased with a maximum of 27% (10-37%). We conclude that surfactant nebulization during HFV improves lung function in rabbits with severe respiratory failure, without improving distribution, but with less effects on blood pressure and cerebral blood flow, when compared with surfactant instillation.