Pressure Measurement System Research Articles

Synthetic dispersion interferometry for relative atmospheric pressure sensing.

We present a modified version of the two-arm, two-color, single second harmonic generation heterodyne dispersion interferometer, as introduced by Irby et. al. [Rev. Sci. Instrum.70, 699 (1999) 10.1063/1.1149489]. The amount of optical elements is reduced and digital in-phase and quadrature demodulation is used to retrieve the phase shift from a single photodetector signal. The intrinsic system noise and drift for this device are analyzed by measuring the Allan deviation. We investigate the use of this device for relative atmospheric pressure measurement. Relative pressure measurements are performed in a pressure chamber and referenced against a piezoresistive pressure transceiver to demonstrate the concept. It was found that the deviation was less than 150 Pa and an error estimation has been derived.

Development of Real-Time Cuffless Blood Pressure Measurement Systems with ECG Electrodes and a Microphone Using Pulse Transit Time (PTT).

Research has shown that pulse transit time (PTT), which is the time delay between the electrocardiogram (ECG) signal and the signal from a photoplethysmogram (PPG) sensor, can be used to estimate systolic blood pressure (SBP) and diastolic blood pressure (DBP) without the need for a cuff. However, the LED of the PPG sensor requires the precise adjustment of both light intensity and light absorption rates according to the contact status of the light-receiving element. This results in the need for regular calibration. In this study, we propose a cuffless blood pressure monitor that measures real-time blood pressure using a microphone instead of a PPG sensor. The blood pulse wave is measured in the radial artery of the wrist using a microphone that can directly measure the sound generated by a body rather than sending energy inside the body and receiving a returning signal. Our blood pressure monitor uses the PTT between the R-peak of the ECG signal and two feature points of the blood pulse wave in the radial artery of the wrist. ECG electrodes and circuits were fabricated, and a commercial microelectromechanical system (MEMS) microphone was used as the microphone to measure blood pulses. The peak points of the blood pulse from the microphone were clear, so the estimated SBP and DBP could be obtained from each ECG pulse in real time, and the resulting estimations were similar to those made by a commercial cuff blood pressure monitor. Since neither the ECG electrodes nor the microphone requires calibration over time, the real-time cuffless blood pressure monitor does not require calibration. Using the developed device, blood pressure was measured three times daily for five days, and the mean absolute error (MAE) and standard deviation (SD) of the SBP and DBP were found to be 2.72 ± 3.42 mmHg and 2.29 ± 3.53 mmHg, respectively. As a preliminary study for proof-of-concept, these results were obtained from one subject. The next step will be a pilot study on a large number of subjects.

Fiber Bragg Gratings based smart insole to measure plantar pressure and temperature

Various foot complications can be easily avoided by continuous monitoring of foot plantar temperature and pressure. In this work, the design, characterization, and implementation of a Fiber Bragg Gratings (FBG) based smart insole capable of simultaneously measuring plantar pressure and temperature has been reported. The instrumented insole was tested and verified during static and gait exercises. The paper also provides a comparison of the developed optoelectronic-based solution with a commercially available and widely used plantar pressure measurement and analysis system and a lab-made, electronic sensor-based smart insole that can measure both plantar temperature and pressure. It was shown that even though the commercially available expensive system is very robust and highly precise due to many sensing units on the insole, the developed insole with a smaller number of sensors can provide both plantar temperature and pressure with reasonable precision while displaying both foot pressure and temperature maps, and gait cycle plots in real-time. The FBG-based solution is comfortable and safer than the other systems being compared. Thus, confirming the effectiveness of the proposed solution as an addition to the research area for detecting foot complications non-invasively using foot insoles.

Polyurethane Scaffold vs Fascia Lata Autograft for Hip Labral Reconstruction: Comparison of Femoroacetabular Biomechanics.

The integrity of the acetabular labrum is critical in providing normal function and minimizing hip degeneration and is considered key for success in today's hip preservation algorithm. Many advances have been made in labral repair and reconstruction to restore the suction seal. To compare the biomechanical effects of segmental labral reconstruction between the synthetic polyurethane scaffold (PS) and fascia lata autograft (FLA). Our hypothesis was that reconstruction with a macroporous polyurethane implant and autograft reconstruction of fascia lata would normalize hip joint kinetics and restore the suction seal. Controlled laboratory study. Ten cadaveric hips from 5 fresh-frozen pelvises underwent biomechanical testing with a dynamic intra-articular pressure measurement system under 3 conditions: (1) intact labrum, (2) reconstruction with PS after a 3-cm segmental labrectomy, then (3) reconstruction with FLA. Contact area, contact pressure, and peak force were evaluated in 4 positions: 90º of flexion in neutral, 90º of flexion plus internal rotation, 90º of flexion plus external rotation, and 20º of extension. A labral seal test was performed for both reconstruction techniques. The relative change from the intact condition (value = 1) was determined for all conditions and positions. PS restored contact area to at least 96% of intact (≥0.96; range, 0.96-0.98) in all 4 positions, and FLA restored contact area to at least 97% (≥0.97; range, 0.97-1.19). Contact pressure was restored to ≥1.08 (range, 1.08-1.11) with the PS and ≥1.08 (range, 1.08-1.10) with the FLA technique. Peak force returned to ≥1.02 (range, 1.02-1.05) with PS and ≥1.02 (range, 1.02-1.07) with FLA. No significant differences were found between the reconstruction techniques in contact area in any position (P > .06), with the exception that FLA presented greater contact area in flexion plus internal rotation as compared with PS (P = .003). Suction seal was confirmed in 80% of PSs and 70% of FLAs (P = .62). Segmental hip labral reconstruction using PS and FLA reapproximated femoroacetabular contact biomechanics close to the intact state. These findings provide preclinical evidence supporting the use of a synthetic scaffold as an alternative to FLA and therefore avoiding donor site morbidity.

Full-scale investigation of heliostat aerodynamics through wind and pressure measurements at a pentagonal heliostat

Wind loads on heliostats are often investigated through experimental wind tunnel studies or numerical simulations. However, these approaches cannot consider the full-scale conditions but require a reproduction and simulation of both the heliostat structure and the wind conditions. Complementary full-scale investigations are therefore crucial but are at the same time relatively costly, as it is cumbersome to set up large heliostats with measurement devices. This paper introduces a new pressure measurement system which is easy-to-apply to a real-scale heliostat and enables full-scale investigations with minimized effort. The results of a first field study are presented during which wind and pressure measurements were taken simultaneously over periods of 10 min at a 48.5 m2 pentagonal Stellio heliostat. The non-dimensional pressure distributions are investigated and it is shown that the mean cp-values are very consistent amongst the measurement periods and reach values between 2.2 and 2.6. These values, in turn, are found to agree well with results of a wind tunnel study. Moreover, the behavior of the load coefficients with varying angles of attack is studied and the aerodynamic admittance functions are evaluated which give in-depth insight into the generation of aerodynamic loads. The admittance functions are found to start decreasing at a non-dimensional frequency of approximately 0.2. This finding indicates that eddies which are about the size of the heliostat or larger are fully effective in generating aerodynamic loads while the effectiveness of smaller eddies is reduced.

Validity and reliability of the XSENSOR in-shoe pressure measurement system.

In-shoe pressure measurement systems are used in research and clinical practice to quantify areas and levels of pressure underfoot whilst shod. Their validity and reliability across different pressures, durations of load and contact areas determine their appropriateness to address different research questions or clinical assessments. XSENSOR is a relatively new pressure measurement device and warrants assessment. Does the XSENSOR in-shoe pressure measurement device have sufficient validity and reliability for clinical assessments in diabetes? Two XSENSOR insoles were examined across two days with two lab-based protocols to assess regional and whole insole loading. The whole insole protocol applied 50-600 kPa of pressure across the insole surface for 30 seconds and measured at 0, 2, 10 and 30 seconds. The regional protocol used two (3.14 and 15.9 cm2 surface area) cylinders to apply pressures of 50, 110 and 200 kPa to each insole. Three trials of all conditions were averaged. The validity (% difference and Root Mean Square Error: RMSE) and repeatability (Bland Altman, Intra-Class Correlation Coefficient: ICC) of the target pressures (whole insole) and contact area (regional) were outcome variables. Regional results demonstrated mean contact area errors of less than 1 cm2 for both insoles and high repeatability (≥0.939). Whole insole measurement error was higher at higher pressures but resulted in average peak and mean pressures error < 10%. Reliability error was 3-10% for peak pressure, within the 15% defined as an analytical goal. Errors associated with the quantification of pressure are low enough that they are unlikely to influence the assessments of interventions or screening of the at-risk-foot considering clinically relevant thresholds. Contact area is accurate due to a high spatial resolution and the repeatability of the XSENSOR system likely makes it appropriate for clinical applications that require multiple assessments.

Central blood pressure: nice to know but not yet ready for routine practice

A few years ago, my division bought new 24-hour blood pressure (BP) measurement devices. One sales argument of the manufacturer was that the new devices can also record central blood pressure, and we thought this is a great added feature. Central blood pressure is regarded as an index of aortic stiffness1 and can be calculated from a noninvasive assessment of arterial pulse wave velocity and calculation of the augmentation index.2 At last, the machines arrived, we first tried them on ourselves (of course), received nice printouts, but then the questions started.

Experimental investigation on the effect of plunging pipe diameter change in cyclones to the performance of cyclones

In this study, in the cyclone designed according to the high-efficiency Stairmand model, three different immersion pipe diameters, four different flow rates, and two different samples were used to examine the pressure loss and dust holding efficiency that affect the cyclone performance. Cyclone separators are fixed-part devices used in the process of separating particles from the gas by forming vortexes with a gas stream containing solid particles. In cyclone separators, the parameters that have the most significant impact on their performance are dust collection efficiency and pressure loss. In this study, temperature measurement with thermocouple and pressure measurement with digital pressure measurement device were made at the inlet and outlet parts of the cyclone. Dust retention efficiency was calculated by the ratio of the weight of the dust entering the cyclone to the weight of the dust accumulated in the dust collection chamber at the end of the experiment. In addition, the obtained data were analyzed by means of SOLIDWORKS FLOW simulation program and compared with the experimental study. The best result in dust retention efficiency in the coal sample was obtained with 374.85 m? per hours flow rate and ?114.3 mm plunge pipe diameter. In the biomass sample, the best dust holding efficiency was obtained with an ?88.9 mm plunge pipe diameter at a flow rate of 374.85 m? per hours.

S-04-3: VALIDATION OF BLOOD PRESSURE DEVICES AS PER 2020 WHO TECHNICAL SPECIFICATIONS: A SCOPING REVIEW OF GLOBAL LITERATURE

Objective: To (1) identify and summarize the global research literature on validation of automated non-invasive blood pressure measurement devices (BPMD) with upper arm cuff, (2) develop a repository of validated BPMD in compliance 2020 WHO technical specifications (3) identify challenges and gaps in evidence base on validated BPMD and develop novel strategies to address them. Design and method: A scoping review was conducted according to the Joanna Briggs Institute methodology using ‘Population, Concept, Context’ concept. Empirical studies validating BPMD complying with the 2020 WHO technical specifications (i.e. semi-automated/automated non-invasive with upper arm cuff), published in English between 2000 and 2022 were eligible for inclusion in the review. We searched MEDLINE, Web of Science, Scopus, EMBASE, CINAHL, CENTRAL, ProQuest and daBL website. We snowballed references from website reports. Title-abstract, full-text screening, and data extraction was conducted in duplicate by four reviewers (PICOPortal, MS Excel). Descriptive data analysis was performed on MS Excel and Tableau. Results: Of 11,825 identified records, we included 269 studies that fulfilled the inclusion criteria. A total of 251 BPMD from 89 manufacturers were assessed for validation methods. Omron (29%), Microlife (10%) and A&amp;D Company (8%) were the top three BPMD manufacturers that underwent validations. China (20%), UK (13%) and USA (12%) were the top three countries where these validations were undertaken. The three most frequently used validation protocols were (Figure1): European Society of Hypertension-International protocol (ESH-IP) 2002 (27%), ESH-IP 2010 (25%) and Modified British Hypertension Society 1993 (16%). Nearly 50%, 40% and 48% of the validated BPMD were intended for use in clinical- and home/self-measurement, and for general adults, respectively. Of the 55% studies that were funded, 72% received support (finances/ BPMD) from device manufacturers. The publications did not reveal details about the following: device manufacturer (13%), country of validation (26%), settings for intended BPMD use (29%), and the target population for BPMD use (22%). Conclusions: While most (89%) of the BPMD included in the review fulfilled the validation criteria, there are considerable gaps in terms of the settings and countries of validation. In designing validation studies, research methods should focus on validating BPMD for specific target population and conditions (e.g. pregnancy or children), and take range of arm circumferences into considerations. Finally, we call for improvement in quality of reporting the validation studies to improve transparency and comparability. This could be best achieved by initiating a dialogue with all stakeholders in blood pressure research and practice.

High pitch sweep rates in supersonic wind tunnel tests

A typical test in a high-Reynolds-number blowdown wind tunnel, such as the VTI T-38 facility in Belgrade, involves a model sweep in a range of angles of attack. Increasing pitch sweep rates can bring two-fold benefit. The angle-of-attack range can be extended in tests at high stagnation pressures with limited run time, or test time can be shortened for the desired angle-of-attack range in other tests, in both cases bringing significant energy savings. The potential effect of the increased pitch rates on measurement data in the VTI T-38 wind tunnel was investigated in a recent supersonic wind tunnel test campaign of a hypervelocity standard model. The Mach 2 tests were performed at pitch rates of 2, 3, 4, 8 and 12° per second. While the wind tunnel balance measurement data were not seemed to be affected, the base pressure data revealed a high dependency on changing pitch sweep rates. It was found that the high lag in pressure piping affected the measured base pressure and, consequently, the forebody axial force, which is an important fact to know when dealing with ‘base drag corrected’ supersonic data. The conclusions derived from the Mach 2 tests have been verified in the additional Mach 4 tests. The verification tests confirmed that, for the currently employed base pressure measurement system, reliable measurement results can be obtained in wind tunnel tests by applying pitch rates up to 3° per second. The recommendations for modifications of the base pressure measurement system have been given.

Development of Intraoperative Plantar Pressure Measurement System Considering Weight Bearing Axis and Center of Pressure

To prevent postoperative complications in corrective surgery for foot deformities such as hallux valgus and pes planus, it is critical to quantitatively predict the postoperative standing-position plantar pressure distribution during the operation. The authors have previously proposed an intraoperative plantar pressure measurement system (IPPM) that allows for the measurement of a supine patient’s plantar pressure distribution that is equivalent to that in the standing position. This system consists of an IPPM device comprising of a force plate and pressure distribution sensor, an optical three-dimensional position measurement device, a navigation monitor, and a PC. The plantar pressure distribution in the standing position is reproduced by navigating the operator, as he or she presses the IPPM device against the patient’s sole so that the weight-bearing axis (floor reaction force vector) and femoral head center are as close to each other as possible. However, in our previous study, the reproducibility of the standing position plantar pressure distribution was insufficient. Therefore, in the present study, we add a navigational function that can be used to bring the centers of pressure in the standing position and under measurement, as well as to correct the IPPM’s self-weight in the measured force. The improved device was used in an experiment with nine healthy subjects, and the similarity of the plantar pressure distribution in the standing and supine positions was evaluated using normalized cross-correlation, yielding an average of 0.90. Furthermore, in an evaluation experiment with ten orthopedic surgeons, it was observed that using the system reproduced the plantar pressure distribution significantly better than when the system was not used. These results indicate that the present system can predict the plantar pressure distribution in the standing position. We believe that this system can contribute to reducing complications after foot surgery.

Prediction Of Postoperative Improvement in Lower Limb Oedema After Endovenous Laser Ablation Using a Noninvasive Venous Pressure Measurement Device

Prediction Of Postoperative Improvement in Lower Limb Oedema After Endovenous Laser Ablation Using a Noninvasive Venous Pressure Measurement Device

Phlebological compression bandaging competence: comparing performance of nurses before and after one-off training

To investigate the differences in applying phlebological compression bandaging (PCB) in nurses before and after one-off training, and to compare the performance of subgroups. Participants received training teaching the correct application of PCB. Participants' competence was measured using the newly developed control score of compression bandaging (CCB score) before and after training, one and three months later. Subgroup analyses compared participants (work setting, wound certification, PCBs applied per week). In total, 47 participants took part (mean age 40.7 years, 85.1% female, 59.6% outpatient nurses, 59.6% >10 years' working experience, 55.3% with a wound certificate). The CCB score improved after training. In all subgroups, the score differed significantly over time (p≤0.002 in all cases) except for participants applying the highest number of PCBs (p=0.241). In hospital-based participants, the CCB score three months after training was considerably, but non-significantly, higher than before training (2.84 versus 4.21, respectively; p=0.068). In participants working in outpatient settings, with and without a wound certificate, and applying a low (<5) and medium (5-10) number of PCBs per week, the CCB score remained significantly higher than before training (p≤0.011 in all cases). All subgroups benefited from training, mostly significantly, and maintained gains in competence for three months. Frequently applying these skills may improve performance. Previously published results showed that ideal pressure-related parameters are rarely achieved. Regular training should be offered, including the use of pressure-measuring devices, allowing nurses to gain experience and develop deeper understanding of correct PCB application.

Perioperative Validation of the TensorTip™ MTX Device for Noninvasive Arterial Pressure Measurement: A Method Comparison Study.

The noninvasive TensorTip™ MTX measures blood pressure by interpreting blood diffusion color of the finger skin. In addition to blood pressure, the device is able to measure various vital signs: heart rate, oxygen saturation, stroke volume, and cardiac output. Studies about accuracy and precision thus far available have only been conducted by the manufacturer. The aim of our study was to investigate the accuracy and precision of the TensorTip MTX in comparison to invasive radial artery blood pressure values. Forty-one patients scheduled for elective surgery were enrolled in this study. Placement of the arterial catheter had to be part of the standard of care. Once hemodynamic stable conditions were achieved, blood pressure was measured. Three measurements with the TensorTip MTX were averaged and compared with one invasive blood pressure measurement using Bland-Altman plot and error grid analysis. Systolic, diastolic, and mean blood pressure had a bias of respectively 6.2, -6.9 and 4.4 mm Hg. Corresponding standard deviation were respectively 30.1, 17.0 and 22.2. Calculated percentage errors were 47.6%, 52.9% and 52.3%. Proportional bias was present in all Bland-Altman analyses. Error grid analysis showed 61.0% of systolic blood pressure measurements, and 46.3% of mean blood pressure measurements were in the clinical acceptable zone. The TensorTip MTX was not able to reliably measure blood pressure compared to blood pressure obtained with an arterial catheter and therefore, the measurement performance is not clinically acceptable. Moreover, a high malfunction rate makes the device unsuitable for use in perioperative period.

High Quasi-static Pressure Measurement of Explosion in Closed Container

To develop a method for determining the parameters of the final equation of state (EOS) of detonation products of aluminized explosives, an explosion quasi-static pressure measurement system in closed containers with a large mass-to-volume ratio is developed. The influence of domestic and foreign typical charge piezoelectric pressure sensors, sensor buffer adjustment structures, container tightness, grounding operation, weather, and other factors on the long-time measurement of high quasi-static pressure are comparatively studied. The test methods and conditions for obtaining standard quasi-static pressure-time curves are clarified. The influence of the mass of different aluminized explosives on the static pressure is obtained. The result shows that the foreign 113B03 type sensor is more suitable for measuring quasi-static pressure with a leakage effect in a humid environment. An appropriate sensor buffer adjustment structure and reliable grounding operation can significantly reduce the high-frequency oscillation of the signal.

Design of a Wireless Passive Pressure Measurement System Using Piezoresistive Materials

In this article, a methodology for wireless and passive pressure measurement systems has been presented based on the principle of inductive-capacitive (LC) sensing. In the proposed method, two flexible carbon composite materials: Velostat and carbon conductive foam have been chosen as the pressure sensing element. Both the materials have the property of piezoresistivity and show the change in resistivity with applied pressure. In the designed sensor, the LC circuit has been modified into an LCR tank circuit with a variable resistor as a sensing element. During the measurement, pressure has been monitored and measured using a reader coil, connected with the impedance analyzer. The change in resistance in Velostat or conductive foam with applied pressure, changes the input impedance, quality factor, and resonance frequency. The proposed measurement system has shown an innovative technique based on an LC pressure measurement system with a resistive sensing element. Both the sensing materials have been taken separately and individual experiments have been performed. The method has been tested and evaluated experimentally, which also analyzes the two carbon-composite-based materials for this type of wireless pressure sensor.

Clinical Utility of the Portable Pressure-Measuring Device for Compression Garment Pressure Measurement on Hypertrophic Scars by Burn Injury during Compression Therapy.

Compression therapy for burn scars can accelerate scar maturation and improve clinical symptoms (pruritus and pain). This study objectively verified the effect of pressure garment therapy in maintaining a therapeutic pressure range for hypertrophic scars. Sixty-five participants (aged 20~70 years) with partial- or full-thickness burns, Vancouver scar scale score of ≥4, and a hypertrophic scar of ≥4 cm × 4 cm were enrolled. Compression pressure was measured weekly using a portable pressure-monitoring device to regulate this pressure at 15~25 mmHg for 2 months. In the control group, the compression garment use duration and all other burn rehabilitation measures were identical except for compression monitoring. No significant difference was noted in the initial evaluations between the two groups (p &gt; 0.05). The improvements in the amount of change in scar thickness (p = 0.03), erythema (p = 0.03), and sebum (p = 0.02) were significantly more in the pressure monitoring group than in the control group. No significant differences were noted in melanin levels, trans-epidermal water loss, or changes measured using the Cutometer® between the two groups. The efficacy of compression garment therapy for burn-related hypertrophic scars can be improved using a pressure-monitoring device to maintain the therapeutic range.

Design and Haemodynamic Analysis of a Novel Anchoring System for Central Venous Pressure Measurement.

In recent years, treatment of heart failure patients has proved to benefit from implantation of pressure sensors in the pulmonary artery (PA). While longitudinal measurement of PA pressure profoundly improves a clinician's ability to manage HF, the full potential of central venous pressure as a clinical tool has yet to be unlocked. Central venous pressure serves as a surrogate for the right atrial pressure, and thus could potentially predict a wider range of heart failure conditions. However, it is unclear if current sensor anchoring methods, designed for the PA, are suitable to hold pressure sensors safely in the inferior vena cava. The purpose of this study was to design an anchoring system for accurate apposition in inferior vena cava and evaluate whether it is a potential site for central venous pressure measurement. A location inferior to the renal veins was selected as an optimal site based on a CT scan analysis. Three anchor designs, a 10-strut anchor, and 5-struts with and without loops, were tested on a custom-made silicone bench model of Vena Cava targeting the infra-renal vena cava. The model was connected to a pulsatile pump system and a heated water bath that constituted an in-vitro simulation unit. Delivery of the inferior vena cava implant was accomplished using a preloaded introducer and a dilator as a push rod to deploy the device at the target area. The anchors were subjected to manual compression tests to evaluate their stability against dislodgement. Computational Fluid Dynamics (CFD) analysis was completed to characterize blood flow in the anchor's environment using pressure-based transient solver. Any potential recirculation zones or disturbances in the blood flow caused by the struts were identified. We demonstrated successful anchorage and deployment of the 10-strut anchor in the Vena Cava bench model. The 10-strut anchor remained stable during several compression attempts as compared with the other two 5-strut anchor designs. The 10-strut design provided the maximum number of contact points with the vessel in a circular layout and was less susceptible to movement or dislodgement during compression tests. Furthermore, the CFD simulation provided haemodynamic analysis of the optimum 10-strut anchor design. This study successfully demonstrated the design and deployment of an inferior vena cava anchoring system in a bench test model. The 10-strut anchor is an optimal design as compared with the two other 5-strut designs; however, substantial in-vivo experiments are required to validate the safety and accuracy of such implants. The CFD simulation enabled better understanding of the haemodynamic parameters and any disturbances in the blood flow due to the presence of the anchor. The ability to place a sensor technology in the vena cava could provide a simple and minimally invasive approach for heart failure patients.

The Development of a Built-In Shoe Plantar Pressure Measurement System for Children.

There is a rapid increase in plantar pressure from the infant to toddler stage, yet little is known about the reasons for this change. More information about plantar pressure distribution can help clinicians identify early-stage foot-related diseases that may occur during transitions from childhood to adulthood. This information also helps designers create shoes that adapt to different needs. This research describes the development of a low-cost, built-in shoe plantar pressure measurement system that determines foot pressure distribution in toddlers. The study aimed to improve and provide data on pressure distribution during foot growth. This was accomplished by implementing a plantar pressure capacitive measurement system within shoes. The capacitive sensors were laminated using a copper tape sheet on plastic backing with adhesive, elastomer layers, and a combination of conductive and non-conductive fabrics. Constructed sensors were characterized using compression tests with repeated loads. Results demonstrated that the sensors exhibited rate-independent hysteresis in the estimation of pressure. This enabled a calibration model to be developed. The system can mimic more expensive plantar pressure measurement systems at lower fidelity. This emerging technology could be utilized to aid clinicians, researchers, and footwear designers interested in how pressure distribution changes from infants to toddlers.

Non-nutritive sucking milestones of preterm infants in Indonesia: a descriptive study

Background Non-nutritive sucking (NNS) maturity has been used as one of the markers of oral feeding readiness in infants. Prematurity may hinder the attainment of NNS milestones. Depending on gestational age (GA) at birth, preterm infants may display various degrees of immaturity, potentially affecting the strength, coordination, and efficiency of skills required for NNS.&#x0D; Objective To identify the progression of NNS patterns across gestational age groups of preterm infants in Indonesia by comparing NNS parameters between moderate-to-late preterm and very preterm infants.&#x0D; Methods NNS evaluation was conducted in 120 preterm infants born at 28-34 weeks gestational age in five tertiary hospitals in Jakarta, Indonesia. Three aspects of NNS (suction pressure, number of suctions per burst, and time between bursts) were documented and arranged to present a descriptive overview. A suction pressure measurement device was used to record, identify, and analyze NNS parameters. We hypothesize that maturity, as determined by GA, positively affected the attainment of NNS milestones.&#x0D; Results Moderate-to-late preterm infants (GA 32 to &lt;37 weeks), compared to very preterm infants (GA 28 to &lt;32 weeks), had higher mean NNS pressure (-79.8 vs. -72.7 mmHg, respectively, P=0.041) and shorter mean time between bursts (6.63 vs. 7.36 s, respectively, P=0.030). Mean number of suctions per burst were also significantly different between the two GA groups (8.90 vs. 8.99 sucks/burst, respectively, P=0.048).&#x0D; Conclusion Maturity, as reflected by GA, had a positive effect on the attainment of NNS milestones in preterm infants in Indonesia. Significant differences in the three NNS parameters: number of suctions per burst, time between bursts, and suction pressure were found between moderate-to-late preterm and very preterm infants.