scholarly journals Dependence of SpO2 signal noise on the pulse oximeter averaging time

2021 ◽  
Vol 7 (2) ◽  
pp. 351-354
Author(s):  
Veronika Rafl-Huttova ◽  
Vit Hlavac ◽  
Jakub Rafl ◽  
Martin Rozanek
Keyword(s):  
Pulse Oximeter ◽  
Noise Level ◽  
Motion Artifacts ◽  
Oxygen Control ◽  
Blood Oxygen Saturation ◽  
Clinical Observations ◽  
Noise Characteristics ◽  
True Value ◽  
Averaging Time ◽  
Two Parameters

Abstract A model of the pulse oximeter, which consists of a transfer function between arterial and peripheral blood oxygen saturation (SpO2) and the noise typical for SpO2 records, is an important part of a mathematical model of oxygenation in neonates that is designed to test and compare different algorithms of oxygen control. The noise level in the SpO2 signal is affected by the averaging time setting of the pulse oximeter. This study aimed to characterize the noise level in the SpO2 signal at the set pulse oximeter averaging times of 2- 4, 8, and 16 seconds. We evaluated SpO2 records of 17 healthy volunteers who underwent a laboratory experiment in which they evoked different types of artifacts. The noise level in the SpO2 signal was characterized by two parameters, the deviation of SpO2 from the true value and the SpO2 time stability, defined as the interval during which the measured SpO2 value remained unchanged. Statistical properties of the noise level for the three averaging times were represented by normalized histograms of both the parameters and varied according to the type of artifact. With motion artifacts, the SpO2 readings deviated from the true value by more than ±2% SpO2 in 10%, 7%, or 5% of the measurements when the set averaging time was 2-4 s, 8 s, or 16 s. The length of the interval over which the SpO2 value remained unchanged was most frequently 2 seconds for all set averaging times. Implementation of the noise characteristics into the computer model of oxygenation in neonates will allow more faithful simulations of the output SpO2 signal that better match clinical observations.

scholarly journals 0588 Ring Pulse Oximeter for Screening of Moderate to Severe OSA: A Pilot Study

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A225-A225
Author(s):  
J Xue ◽  
R Zhao ◽  
J Li ◽  
L Zhao ◽  
B Zhou ◽  
...  
Keyword(s):  
Pilot Study ◽  
Pulse Oximeter ◽  
Characteristic Curve ◽  
Diagnostic Value ◽  
Receiver Operator Characteristic Curve ◽  
Oxygen Desaturation ◽  
Significant Difference ◽  
Acceptance Range ◽  
The Difference ◽  
Two Parameters

Abstract Introduction To evaluate the utility of the ring pulse oximeter for screening of OSA in adults. Methods 87 adults were monitored by a ring pulse oximeter and PSG simultaneously during a nocturnal in-lab sleep testing. 3% oxygen desaturation index (ODI3); Mean oxygen saturation(MSpO2), Saturation impair time below 90% (SIT90) derived from an automated algorithm of the ring pulse oximeter. Meanwhile, the parameters of PSG were scored manually according to the AASM Manual. Correlation and receiver operator characteristic curve analysis were used to measure the accuracy of ring pulse oximeter and its diagnostic value for moderate to severe OSA (AHI≥15). Results Among the 87 participants, 18 cases were AHI<5, 17 cases were diagnosed with mild OSA (AHI:5-14.9), 25 cases were diagnosed with moderate OSA (AHI:15-29.9) and 27 cases were diagnosed with severe OSA (AHI≥30). There was no significant difference between PSG and ring pulse oximeter in regard to ODI3 (23.4±23.5 vs 24.7 ± 21.7), and SIT90 (1.54%, range 0.14%-8.99% vs. 3.20%, range 0.60%, 12.30%) (P>0.05], Further analysis indicated that two parameters from the oximeter correlated well with that derived from PSG (r=0.889, 0.567, respectively, both p<0.05). Although MSpO2 correlated significantly (r=0.448, P<0.05), the difference was remarkable [95.9%, range 94.0% to 97.0% vs. 94.5%, range 93.3% to 95.7%, p<0.05]. Bland-Altman plots showed that the agreement of these three parameters was within the clinical acceptance range. The ROC curve showed that the sensitivity and specificity of the ring pulse oximeter when the oximeter derived ODI3 ≥12.5 in the diagnosis of moderate to severe OSA were 82.7% and 74.3%, respectively. Conclusion The pilot study indicated that ring pulse oximeter can detect oxygen desaturation events accurately, therefore to be used as a screening tool for moderate to severe OSA. Support The study was supported by the National Natural Science Foundation of China (No. 81420108002 and NO. 81570083).

Effects of Diffuser Vane Geometries on Compressor Performance and Noise Characteristics in a Centrifugal Compressor

2013 ◽  
Author(s):  
Yohei Morita ◽  
Nobumichi Fujisawa ◽  
Takashi Goto ◽  
Yutaka Ohta
Keyword(s):  
Centrifugal Compressor ◽  
Noise Level ◽  
Leading Edge ◽  
Broadband Noise ◽  
Frequency Noise ◽  
Numerical Techniques ◽  
Vaned Diffuser ◽  
Noise Characteristics ◽  
Edge Vortex ◽  
Compressor Performance

The effects of the diffuser vane geometries on the compressor performance and noise characteristics of a centrifugal compressor equipped with vaned diffusers were investigated by experiments and numerical techniques. Because we were focusing attention on the geometries of the diffuser vane’s leading edge, diffuser vanes with various leading edge geometries were installed in a vaned diffuser. A tapered diffuser vane with the tapered portion near the leading edge of the diffuser’s hub-side could remarkably reduce both the discrete frequency noise level and broadband noise level. In particular, a hub-side tapered diffuser vane with a taper on only the hub-side could suppress the development of the leading edge vortex (LEV) near the shroud side of the diffuser vane and effectively enhanced the compressor performance.

Randomised crossover trial comparing algorithms and averaging times for automatic oxygen control in preterm infants

2021 ◽  
pp. fetalneonatal-2021-322096
Author(s):  
Christoph E Schwarz ◽  
Karen B Kreutzer ◽  
Lukas Langanky ◽  
Nicole S Wolf ◽  
Wolfgang Braun ◽  
...  
Keyword(s):  
Preterm Infants ◽  
Neonatal Intensive Care ◽  
Random Order ◽  
Target Range ◽  
Oxygen Control ◽  
Non Invasive ◽  
Fraction Of Inspired Oxygen ◽  
Averaging Time ◽  
Randomised Controlled ◽  
Gestational Age At Birth

ObjectiveAutomatic control (SPOC) of the fraction of inspired oxygen (FiO2), based on continuous analysis of pulse oximeter saturation (SpO2), improves the proportion of time preterm infants spend within a specified SpO2-target range (Target%). We evaluated if a revised SPOC algorithm (SPOCnew, including an upper limit for FiO2) compared to both routine manual control (RMC) and the previously tested algorithm (SPOCold, unrestricted maximum FiO2) increases Target%, and evaluated the effect of the pulse oximeter’s averaging time on controlling the SpO2 signal during SPOC periods.DesignUnblinded, randomised controlled crossover study comparing 2 SPOC algorithms and 2 SpO2 averaging times in random order: 12 hours SPOCnew and 12 hours SPOCold (averaging time 2 s or 8 s for 6 hours each) were compared with 6-hour RMC. A generated list of random numbers was used for allocation sequence.SettingUniversity-affiliated tertiary neonatal intensive care unit, GermanyPatientsTwenty-four infants on non-invasive respiratory support with FiO2 >0.21 were analysed (median gestational age at birth, birth weight and age at randomisation were 25.3 weeks, 585 g and 30 days).Main outcome measureTarget%.ResultsMean (SD) [95% CI] Target% was 56% (9) [52, 59] for RMC versus 69% (9) [65, 72] for SPOCold_2s, 70% (7) [67, 73] for SPOCnew_2s, 71% (8) [68, 74] for SPOCold_8s and 72% (8) [69, 75] for SPOCnew_8s.ConclusionsIrrespective of SpO2-averaging time, Target% was higher with both SPOC algorithms compared to RMC. Despite limiting the maximum FiO2, SPOCnew remained significantly better at maintaining SpO2 within target range compared to RMC.Trial registrationNCT03785899

scholarly journals Automatic Oxygen Delivery System for Premature Babies

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Thao P. Do ◽  
Lindsey J. Eubank ◽  
Devin S. Coulter ◽  
John M. Freihaut ◽  
Carlos E. Guevara ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Oxygen Concentration ◽  
Delivery System ◽  
Pulse Oximeter ◽  
Oxygen Delivery ◽  
Supplemental Oxygen ◽  
Saturation Level ◽  
Blood Oxygen ◽  
Blood Oxygen Saturation ◽  
Oxygen Saturation Level

When an infant is born prematurely, there are a number of health risks. Among these are underdeveloped lungs, which can lead to abnormal gas exchange of oxygen or hypoxemia. Hypoxemia is treated through oxygen therapy, which involves the delivery of supplemental oxygen to the patient but there are risks associated with this method. Risks include retinopathy, which can cause eye damage when oxygen concentration is too high, and brain damage, when the concentration is too low [1]. Supplemental oxygen concentration must be controlled rigorously. Currently healthcare staff monitors infants’ blood oxygen saturation level using a pulse oximeter. They manually adjust the oxygen concentration using an air-oxygen blender. Inconsistent manual adjustments can produce excessive fluctuations and cause the actual oxygen saturation level to deviate from the target value. Precision and accuracy are compromised. This project develops an automatic oxygen delivery system that regulates the supplemental oxygen concentration to obtain a target blood oxygen saturation level. A microprocessor uses a LABVIEW® program to analyze pulse oximeter and analyzer readings and control electronic valves in a redesigned air-oxygen blender. A user panel receives a target saturation level, displays patient data, and signals alarms when necessary. The prototype construction and testing began February 2010.

Use of Pulse Oximetry in Radiotherapy

2015 ◽  
Vol 1084 ◽  
pp. 515-518
Author(s):  
Nina I. Martemyanova ◽  
Natalia D. Turgunova ◽  
Aleksandr N. Aleinik
Keyword(s):  
Radiation Therapy ◽  
Pulse Oximeter ◽  
High Reliability ◽  
The Body ◽  
Good Resolution ◽  
Blood Oxygen ◽  
Blood Oxygen Saturation ◽  
Arterial Blood ◽  
Arterial Blood Oxygen ◽  
The Impact

Reflectance pulse oximeter is designed to determine arterial blood oxygen saturation during a radiation therapy. Proposed solutions promote to reduce the impact of sensor motion on the readings. Experimentally obtained optimal contact pressure of the sensor on the body is 0.7 N. The preliminary results show that the device has good resolution and high reliability.

scholarly journals Use of Transforms in Biomedical Signal Processing and Analysis

2021 ◽  
Author(s):  
Ette Harikrishna ◽  
Komalla Ashoka Reddy
Keyword(s):  
Wavelet Transforms ◽  
Research Work ◽  
Reference Signal ◽  
Low Frequency ◽  
Motion Artifact ◽  
Motion Artifacts ◽  
Biomedical Signal Processing ◽  
Blood Oxygen Saturation ◽  
Biomedical Signals ◽  
Electrocardiogram Ecg

Biomedical signals like electrocardiogram (ECG), photoplethysmographic (PPG) and blood pressure were very low frequency signals and need to be processed for further diagnosis and clinical monitoring. Transforms like Fourier transform (FT) and Wavelet transform (WT) were extensively used in literature for processing and analysis. In my research work, Fourier and wavelet transforms were utilized to reduce motion artifacts from PPG signals so as to produce correct blood oxygen saturation (SpO2) values. In an important contribution we utilized FT for generation of reference signal for adaptive filter based motion artifact reduction eliminating additional sensor for acquisition of reference signal. Similarly we utilized the transforms for other biomedical signals.

A Comparison of Beat Frequency Estimation Methods for Large Ring Laser

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jailos Mrisho Nzumile ◽  
Keyword(s):  
Real Time ◽  
Noise Level ◽  
Ring Laser ◽  
Frequency Estimation ◽  
Low Noise ◽  
Estimation Methods ◽  
Acquisition Rate ◽  
Large Ring ◽  
True Value ◽  
Output Characteristics

Autoregressive (AR2) technique has always been used to estimate frequency of the output signal from Large ring laser. However, the acquisition rate is not at near real time which is the requirement and noise level still challenge the process resulting to errors in the final estimation. A research was done to compare the Autoregressive (AR2) with the counterparts such as Pisarenko, Quinn, Hilbert and Phase looking for a better technique that will estimate the frequency at near real time to minimize errors. Secondary data from G and C – II ring laser were used during the comparison between the techniques and Autoregressive (AR2). Results shows that, the output characteristics from the counterpart does not depict the oscillations of the Earth rotation as expected contrast to that of Autoregressive (AR2) which does. Moreover, there were much deviation from the expected true value for the techniques contrast to that of AR2 which is very minimum. On the other hand, when the C – II data were used, it was observed that both techniques resemble on their output characteristics though AR2 was still better in the acquisition rate expect for Hilbert transform which does not resemble with others. Following the scope of this paper, Autoregressive (AR2) technique still emerge as a favorite frequency estimation technique contrast to the four counterparts due to its robustness, high acquisition rate as well as low noise level.

scholarly journals Development of a Wearable Reflection-Type Pulse Oximeter System to Acquire Clean PPG Signals and Measure Pulse Rate and SpO2 with and without Finger Motion

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1905
Author(s):  
Partha Pratim Banik ◽  
Shifat Hossain ◽  
Tae-Ho Kwon ◽  
Hyoungkeun Kim ◽  
Ki-Doo Kim
Keyword(s):  
Pulse Rate ◽  
Pulse Oximeter ◽  
Electronic Circuit ◽  
Absolute Error ◽  
Motion Artifact ◽  
Motion Artifacts ◽  
Percentage Error ◽  
Signal Acquisition ◽  
Analog Filter ◽  
Finger Motion

Clinical devices play a vital role in diagnosing and monitoring people’s health. A pulse oximeter (PO) is one of the most common clinical devices for critical medical care. In this paper, we explain how we developed a wearable PO. We propose a new electronic circuit based on an analog filter that can separate red and green photoplethysmography (PPG) signals, acquire clean PPG signals, and estimate the pulse rate (PR) and peripheral capillary oxygen saturation (SpO2). We propose a PR and SpO2 measurement algorithm with and without the motion artifact. We consider three types of motion artifacts with our acquired clean PPG signal from our proposed electronic circuit. To evaluate our proposed algorithm, we measured the accuracy of our estimated SpO2 and PR. To evaluate the quality of our estimated PR (bpm) and SpO2 (%) with and without the finger motion artifact, we used the quality evaluation metrics: mean absolute percentage error (MAPE), mean absolute error (MAE), and reference closeness factor (RCF). Without the finger motion condition, we found that our proposed wearable PO device achieved an average 2.81% MAPE, 2.08 bpm MAE, 0.97 RCF, and 98.96% SpO2 accuracy. With a finger motion, the proposed wearable PO device achieved an average 4.5% MAPE, 3.66 bpm MAE, 0.96 RCF, and 96.88% SpO2 accuracy. We also show a comparison of our proposed PO device with a commercial Fingertip PO (FPO) device. We have found that our proposed PO device performs better than the commercial FPO device under finger motion conditions. To demonstrate the implementation of our wearable PO, we developed a smartphone app to allow the PO device to share PPG signals, PR, and SpO2 through Bluetooth communication. We also show the possible applications of our proposed PO as a wearable, hand-held PO device, and a PPG signal acquisition system.

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