scholarly journals The Effect of Optical Crosstalk on Accuracy of Reflectance-Type Pulse Oximeter for Mobile Healthcare

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Hyun Jae Baek ◽  
JaeWook Shin ◽  
Jaegeol Cho
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Skin Color ◽  
Large Error ◽  
Skin Changes ◽  
Light Emitting ◽  
Optical Crosstalk ◽  
Mobile Healthcare ◽  
The Difference ◽  
Pulse Oximeters

According to the theoretical equation of the pulse oximeter expressed by the ratio of amplitude (AC) and baseline (DC) obtained from the photoplethysmographic signal of two wavelengths, the difference of the amount of light absorbed depending on the melanin indicating the skin color is canceled by normalizing the AC value to the DC value of each wavelength. Therefore, theoretically, skin color does not affect the accuracy of oxygen saturation measurement. However, if there is a direct path for the light emitting unit to the light receiving unit instead of passing through the human body, the amount of light reflected by the surface of the skin changes depending on the color of the skin. As a result, the amount of crosstalk that varies depending on the skin color affects the ratio of AC to DC, resulting in errors in the calculation of the oxygen saturation value. We made crosstalk sensors and crosstalk-free sensors and performed desaturation experiments with respiratory gas control on subjects with various skin colors to perform oxygen saturation measurements ranging from 60 to 100%. Experimental results showed that there was no difference in the measurement error of oxygen saturation according to skin color in the case of the sensor which prevented crosstalk (−0.8824 ± 2.2859 for Asian subjects, 0.6741 ± 3.2822 for Caucasian subjects, and 0.9669 ± 2.2268 for African American subjects). However, a sensor that did not prevent crosstalk showed a large error in dark skin subjects (0.8258 ± 2.1603 for Asian subjects, 0.8733 ± 1.9716 for Caucasian subjects, and −3.0591 ± 3.9925 for African Americans). Based on these results, we reiterate the importance of sensor design in the development of pulse oximeters using reflectance-type sensors.

Design of Reflectance Pulse Oximeter and BPM using the Max30100 Sensor in Early Detection of Hypoxemia in Patients with Cardiovascular Disorders

2021 ◽  
Vol 1 (1) ◽  
pp. 1-6
Author(s):  
Chiu-Hua Huang ◽  
Jia-Wei Guo
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Light Emitting Diode ◽  
Blood Gas Analysis ◽  
Large Error ◽  
Gas Analysis ◽  
Measuring Instruments ◽  
Blood Oxygen Saturation ◽  
Organic Light Emitting Diode ◽  
The Difference

Blood oxygen saturation meter is a tool used to monitor the state of oxygen saturation in the blood and also the patient's heart rate (BPM) and to assist in the physical assessment of the patient without going through blood gas analysis. Oxygen saturation measuring devices usually use the difference in the wavelengths of red and infrared led light that will be captured by the photodiode. The purpose of this research is to make a pulse oximeter equipped with a display of SPO2, BPM values ​​and an additional SP02 signal. The design of this measuring instrument uses the MAX30100 sensor, the minimum system circuit of Arduino ATmega328p and OLED (Organic Light-Emitting Diode). Data from the MAX30100 sensor enters the I2C pin on the minimum Arduino system, then the microcontroller is processed to produce the percentage of SPO2 value, BPM value, and SPO2 signal which is then displayed on the OLED. The test is done by comparing the module with standard measuring instruments which produces the largest % error of 0.81% for Spo2 and 0.87% for BPM. The error presentation is obtained from factor measurements, if there is finger movement it will cause a large error. From the results obtained, the tool is still feasible to use because in the "Guidelines for Testing and Calibrating Medical Devices" Ministry of Health RI 2001, the maximum limit in the pulse oximeter error tolerance is for Spo2 1% and BPM 5%.

scholarly journals Is pulse oximeter a reliable tool for non-critically ill patients with COVID-19?

2021 ◽  
Author(s):  
Aslıhan Gürün Kaya ◽  
Miraç Öz ◽  
İREM AKDEMİR KALKAN ◽  
Ezgi Gülten ◽  
güle AYDIN ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Lymphocyte Count ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Arterial Blood Gas ◽  
Reactive Protein ◽  
Arterial Blood ◽  
The Difference ◽  
Clinical Conditions

Introduction: Guidelines recommend using a pulse oximeter rather than arterial blood gas (ABG) for COVID-19 patients. However, significant differences can be observed between oxygen saturation measured by pulse oximetry (SpO2) and arterial oxygen saturation (SaO2) in some clinical conditions. We aimed to assess the reliability of pulse oximeter in patients with COVID-19 Methods: We retrospectively reviewed ABG analyses and SpO2 levels measured simultaneously with ABG in patients hospitalized in COVID-19 wards. Results: We categorized total 117 patients into two groups; in whom the difference between SpO2 and SaO2 was 4% (acceptable difference) and >4% (large difference). Large difference group exhibited higher neutrophil count, C-reactive protein, ferritin, fibrinogen, D-dimer and lower lymphocyte count. Multivariate analyses revealed that increased fibrinogen, increased ferritin and decreased lymphocyte count were independent risk factors for large difference between SpO2 and SaO2. The total study group demonstrated the negative bias of 4.02% with the limits of agreement of −9.22% to 1.17%. The bias became significantly higher in patients with higher ferritin, fibrinogen levels and lower lymphocyte count. Conclusion: Pulse oximeters may not be sufficient to assess actual oxygen saturation especially in COVID-19 patients with high ferritin and fibrinogen levels and low lymphocyte count low SpO2 measurements.

scholarly journals First Evaluation of a Newly Constructed Underwater Pulse Oximeter for Use in Breath-Holding Activities

2021 ◽  
Vol 12 ◽  
Author(s):  
Eric Mulder ◽  
Erika Schagatay ◽  
Arne Sieber
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Arterial Oxygen Saturation ◽  
Dropout Rate ◽  
Arterial Oxygen ◽  
Breath Holding ◽  
Signal Loss ◽  
Physiological Variables ◽  
Dry Conditions ◽  
Pulse Oximeters

Studying risk factors in freediving, such as hypoxic blackout, requires development of new methods to enable remote underwater monitoring of physiological variables. We aimed to construct and evaluate a new water- and pressure proof pulse oximeter for use in freediving research. The study consisted of three parts: (I) A submersible pulse oximeter (SUB) was developed on a ruggedized platform for recording of physiological parameters in challenging environments. Two MAX30102 sensors were used to record plethysmograms, and included red and infra-red emitters, diode drivers, photodiode, photodiode amplifier, analog to digital converter, and controller. (II) We equipped 20 volunteers with two transmission pulse oximeters (TPULS) and SUB to the fingers. Arterial oxygen saturation (SpO2) and heart rate (HR) were recorded, while breathing room air (21% O2) and subsequently a hypoxic gas (10.7% O2) at rest in dry conditions. Bland-Altman analysis was used to evaluate bias and precision of SUB relative to SpO2 values from TPULS. (III) Six freedivers were monitored with one TPULS and SUB placed at the forehead, during a maximal effort immersed static apnea. For dry baseline measurements (n = 20), SpO2 bias ranged between −0.8 and −0.6%, precision between 1.0 and 1.5%; HR bias ranged between 1.1 and 1.0 bpm, precision between 1.4 and 1.9 bpm. For the hypoxic episode, SpO2 bias ranged between −2.5 and −3.6%, precision between 3.6 and 3.7%; HR bias ranged between 1.4 and 1.9 bpm, precision between 2.0 and 2.1 bpm. Freedivers (n = 6) performed an apnea of 184 ± 53 s. Desaturation- and resaturation response time of SpO2 was approximately 15 and 12 s shorter in SUB compared to TPULS, respectively. Lowest SpO2 values were 76 ± 10% for TPULS and 74 ± 13% for SUB. HR traces for both pulse oximeters showed similar patterns. For static apneas, dropout rate was larger for SUB (18%) than for TPULS (<1%). SUB produced similar SpO2 and HR values as TPULS, both during normoxic and hypoxic breathing (n = 20), and submersed static apneas (n = 6). SUB responds more quickly to changes in oxygen saturation when sensors were placed at the forehead. Further development of SUB is needed to limit signal loss, and its function should be tested at greater depth and lower saturation.

scholarly journals Proof-of-Concept Simulasi Kadar Saturasi Oksigen untuk Evaluasi Pulse Oximeter

2018 ◽  
Vol 6 (1) ◽  
pp. 110
Author(s):  
FUAD UGHI
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Light Emitting Diode ◽  
System Level ◽  
Proof Of Concept ◽  
Led Driver ◽  
Digital To Analog Converter ◽  
Light Emitting ◽  
Analog Converter ◽  
Digital To Analog

ABSTRAKSimulator SpO2 yang mengemulasikan sinyal yang ekuivalen dengan saturasi oksigen pada manusia, dapat digunakan untuk evaluasi repeatibility pulse oximeter. Simulator ini tersedia di pasaran dengan harga yang cukup mahal di Indonesia, di kisaran 80-100 juta rupiah. Studi ini bertujuan untuk mengembangkan simulator SpO2 dengan biaya rendah, menggunakan komponen elektronika umum yang ada di pasaran. Karakteristik simulasi mengacu kepada referensi yang diambil dari simulator komersial dengan menggunakan sistem akuisisi data berbasis LabVIEW. Kadar saturasi oksigen disimulasikan dengan mengatur intensitas cahaya light emitting diode (LED), untuk meniru penyerapan cahaya oleh darah pada pembuluh arteri. Digital to analog converter digunakan sebagai LED driver, untuk mengatur besar tegangan ke LED yang berbanding lurus dengan intensitas cahaya. Sebagai pembuktian konsep, studi ini berhasil menyimulasikan kadar saturasi oksigen 80% dengan galat mencapai 11.25%, dan 80 denyut jantung per menit dengan galat 6.25%. Hasil simulasi belum bisa dibandingkan dengan simulator komersial, karena hasil yang belum stabil. Total biaya untuk komponen perangkat keras, mencapai satu juta rupiah.Kata kunci: simulator, saturasi oksigen, pulse oximeter, digital to analog converter, light emitting diode ABSTRACTSpO2 simulator, which emulates signal that equivalent to oxygen saturation level of human, can be used to evaluate repeatibility of pulse oximeter. SpO2 simulators are available in Indonesia, but the price is quite expensive, in range of 80-100 million rupiah. The study aims to develop low-cost SpO2 simulator, using common electronic components. Characteristic of simulation refer to reference data, which taken from commercial simulator using LabVIEW based data acquisition system. Level of oxygen saturation is simulated by adjusting beam intensity of light emitting diode (LED), to imitate light absorbance by arterial blood. Digital to analog converter is used as LED driver, to control voltage to LED that directly proportional to light intensity. As a proof of concept, SpO2 simulation has been successfully performed at level 80% with error reaches 11.25% deviation, and heart rate 80 beat per minute with error reaches 6.25%. The simulation result had not compared yet to a commercial simulator, due to the unstable result. Total cost for hardware components of the prototype is around one million rupiah.Keywords: simulator, oxygen saturation, pulse oximeter, digital to analog converter, light emitting diode

Four Types of Pulse Oximeters Accurately Detect Hypoxia during Low Perfusion and Motion

2018 ◽  
Vol 128 (3) ◽  
pp. 520-530 ◽  
Author(s):  
Aaron Louie ◽  
John R. Feiner ◽  
Philip E. Bickler ◽  
Laura Rhodes ◽  
Michael Bernstein ◽  
...  
Keyword(s):  
Root Mean Square Error ◽  
Oxygen Saturation ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Pulse Oximeter ◽  
Motion Artifacts ◽  
Arterial Oxygen ◽  
Mean Square ◽  
Blood Samples ◽  
Pulse Oximeters

Abstract Background Pulse oximeter performance is degraded by motion artifacts and low perfusion. Manufacturers developed algorithms to improve instrument performance during these challenges. There have been no independent comparisons of these devices. Methods We evaluated the performance of four pulse oximeters (Masimo Radical-7, USA; Nihon Kohden OxyPal Neo, Japan; Nellcor N-600, USA; and Philips Intellivue MP5, USA) in 10 healthy adult volunteers. Three motions were evaluated: tapping, pseudorandom, and volunteer-generated rubbing, adjusted to produce photoplethsmogram disturbance similar to arterial pulsation amplitude. During motion, inspired gases were adjusted to achieve stable target plateaus of arterial oxygen saturation (SaO2) at 75%, 88%, and 100%. Pulse oximeter readings were compared with simultaneous arterial blood samples to calculate bias (oxygen saturation measured by pulse oximetry [SpO2] − SaO2), mean, SD, 95% limits of agreement, and root mean square error. Receiver operating characteristic curves were determined to detect mild (SaO2 < 90%) and severe (SaO2 < 80%) hypoxemia. Results Pulse oximeter readings corresponding to 190 blood samples were analyzed. All oximeters detected hypoxia but motion and low perfusion degraded performance. Three of four oximeters (Masimo, Nellcor, and Philips) had root mean square error greater than 3% for SaO2 70 to 100% during any motion, compared to a root mean square error of 1.8% for the stationary control. A low perfusion index increased error. Conclusions All oximeters detected hypoxemia during motion and low-perfusion conditions, but motion impaired performance at all ranges, with less accuracy at lower SaO2. Lower perfusion degraded performance in all but the Nihon Kohden instrument. We conclude that different types of pulse oximeters can be similarly effective in preserving sensitivity to clinically relevant hypoxia.

Abstract 276: Impact of Skin Color on Accuracy of Capillary Refill Time Measurement by Pulse Oximeter

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_2) ◽  
Author(s):  
Amanda Nickel ◽  
Shen Jiang ◽  
Natalie Napolitano ◽  
Kota Saeki ◽  
Hideaki Hirahara ◽  
...  
Keyword(s):  
Pulse Oximeter ◽  
Skin Color ◽  
Pearson Correlation ◽  
Middle Finger ◽  
Visual Assessment ◽  
Waveform Analysis ◽  
Capillary Refill Time ◽  
Capillary Refill ◽  
Significant Difference ◽  
The Difference

Capillary refill time(CRT) is a non-invasive method to assess tissue perfusion, routinely performed in pediatric practice. Current methods to measure CRT have limitations in objectivity and reproducibility. The measurement depends on clinician’s assessment. New analytic approach using pulse oximeter waveform has been developed. Hypothesis: CRT measured by pulse oximeter device and clinicians(critical care/anesthesiologist attending physicians) were different across skin color and finger thickness. Method: Children(1-12 yr) with different skin color tones (Fitzpatrick scale 1-2:fair, 3-4:medium, 5-6:dark) were recruited. Subjects were randomized to a pulse oximeter either on index/middle finger, and had a total 10 CRT measurements (5 with device, 5 with clinician’s visual assessment, alternating). Waveform analysis was performed with quick compression and release on the pulse oximetry device by clinician. The difference between device and clinician measured CRT was calculated. ANOVA for difference in CRT across 3 skin color categories and across 4 finger thickness. Result: 64 subjects(skin color fair 33, medium 16, dark 15) were recruited (median age 72 m, IQR 42-123m). Out of 640 CRT measurements, 300 pairs had measurable CRTs in both device and clinician. Based on clinician’s measurement, 114 CRTs were >2s and 26 CRTs > 4s. The overall CRT difference was mean 0.97±1.32s. The CRT difference by skin color was fair 0.86±1.35s, medium 0.90±1.31s, dark 1.26±1.22s, p=0.095. Pearson correlation coefficient was all 0.49 (fair 0.31, medium 0.67, and dark 0.41, all p<0.001). There was no significant difference in CRT difference among 4 finger thickness categories(thin to thick); 1.21±1.48s, 0.94±1.48s, 1.12±1.20s, 0.75±1.20s, p=0.108. Conclusion: The difference between device and clinician measured CRT did not vary across the different patient skin color or finger thickness. Device measured CRT may be a helpful indicator for peripheral perfusion.

scholarly journals How Well Can Anaesthetists Discriminate Pulse Oximeter Tones?

2005 ◽  
Vol 33 (4) ◽  
pp. 497-500 ◽  
Author(s):  
R. W. Morris ◽  
P. J. Mohacsi
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Quantitative Estimation ◽  
Auditory Signal ◽  
Musical Scale ◽  
Patient Simulator ◽  
Median Estimate ◽  
Qualitative Estimate ◽  
The Difference ◽  
High Fidelity Patient Simulator

The ability of experienced anaesthetists to discern oxygen saturation by listening to the tones of a Datex AS3 pulse oximeter was examined. Five-second samples were recorded using a high fidelity patient simulator and replayed singly and in pairs. Whilst the lower saturations were generally recognized as lower, the perceived range was greatly compressed. Median perceived estimates for 70% saturation was 89%, for 80% was 93% and for 94% was 94%. When comparing pairs of samples, the direction of the difference was correctly discerned by 70% of anaesthetists for differences of 2%, rising to 95% for differences of greater than 8% oxygen saturation. The magnitude of the difference was consistently underestimated. With an actual difference of 20%, the median estimate was 5%. The results indicate that while qualitative estimate changes in oxygen saturation are moderately reliable, quantitative estimation is severely limited by a compromised perceived scale. This may lead to underestimation of the severity if the auditory signal is relied on in isolation. A non-linear (musical) scale may prove more appropriate and should be investigated. Testing experienced anaesthetists demonstrated that most could detect the direction, but not the magnitude of a change in saturation by listening to the change in pitch of a Datex AS3 pulse oximeter tone.

Effects of Skin Pigmentation on Pulse Oximeter Accuracy at Low Saturation

2005 ◽  
Vol 102 (4) ◽  
pp. 715-719 ◽  
Author(s):  
Philip E. Bickler ◽  
John R. Feiner ◽  
John W. Severinghaus
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Arterial Oxygen Saturation ◽  
Skin Pigmentation ◽  
Arterial Oxygen ◽  
Dark Light ◽  
Light Skin ◽  
End Tidal ◽  
Pulse Oximeters

Background It is uncertain whether skin pigmentation affects pulse oximeter accuracy at low HbO2 saturation. Methods The accuracy of finger pulse oximeters during stable, plateau levels of arterial oxygen saturation (Sao2) between 60 and 100% were evaluated in 11 subjects with darkly pigmented skin and in 10 with light skin pigmentation. Oximeters tested were the Nellcor N-595 with the OxiMax-A probe (Nellcor Inc., Pleasanton, CA), the Novametrix 513 (Novametrix Inc., Wallingford, CT), and the Nonin Onyx (Nonin Inc., Plymouth, MN). Semisupine subjects breathed air-nitrogen-carbon dioxide mixtures through a mouthpiece. A computer used end-tidal oxygen and carbon dioxide concentrations determined by mass spectrometry to estimate breath-by-breath Sao2, from which an operator adjusted inspired gas to rapidly achieve 2- to 3-min stable plateaus of desaturation. Comparisons of oxygen saturation measured by pulse oximetry (Spo2) with Sao2 (by Radiometer OSM3) were used in a multivariate model to determine the interrelation between saturation, skin pigmentation, and oximeter bias (Spo2 - Sao2). Results At 60-70% Sao2, Spo2 (mean of three oximeters) overestimated Sao2 (bias +/- SD) by 3.56 +/- 2.45% (n = 29) in darkly pigmented subjects, compared with 0.37 +/- 3.20% (n = 58) in lightly pigmented subjects (P &lt; 0.0001). The SD of bias was not greater with dark than light skin. The dark-light skin differences at 60-70% Sao2 were 2.35% (Nonin), 3.38% (Novametrix), and 4.30% (Nellcor). Skin pigment-related differences were significant with Nonin below 70% Sao2, with Novametrix below 90%, and with Nellcor at all ranges. Pigment-related bias increased approximately in proportion to desaturation. Conclusions The three tested pulse oximeters overestimated arterial oxygen saturation during hypoxia in dark-skinned individuals.

DESIGN OF A RING-TYPE REFLECTION PULSE OXIMETER WITH A PARABOLIC REFLECTOR

2015 ◽  
Vol 27 (01) ◽  
pp. 1550007 ◽  
Author(s):  
Chun-Hao Lu ◽  
Jiun-Hung Lin ◽  
Han-Ming Huang ◽  
Cheng-Yang Huang ◽  
Cheng-Chi Tai
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Clinical Medicine ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Parabolic Reflector ◽  
Ring Type ◽  
Reflected Light ◽  
Pulse Oximeters

A pulse oximeter is a noninvasive instrument used in clinical medicine to monitor arterial oxygen saturation. Fingertip-type pulse oximeters are popular, but their inconvenience for long-term monitoring in daily life means that other types of wearable pulse oximeters, such as a ring-type reflection pulse oximeter, needs to be developed. However, designing a ring-type pulse oximeter for measuring the oxygen saturation is difficult due to the complex tissue architecture of the finger base. This study used human tissue simulations to evaluate the practicability of a ring-type reflection pulse oximeter design. Moreover, given that the collection of diffusely reflected light can be enhanced by using a parabolic reflector, the efficacy of a ring-type reflection pulse oximeter with a parabolic reflector was also evaluated.

scholarly journals Effect of Laser Irradiation on Emissivity of Flame-Generated Nanooxides

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2303
Author(s):  
Silvana De Iuliis ◽  
Roberto Dondè ◽  
Igor Altman
Keyword(s):  
Laser Irradiation ◽  
Light Emission ◽  
Energy Gap ◽  
Particle Temperature ◽  
Electron Excitation ◽  
Flame Spray ◽  
Energy Bands ◽  
Light Emitting ◽  
Spectral Behavior ◽  
The Difference

The application of pyrometry to retrieve particle temperature in particulate-generating flames strictly requires the knowledge of the spectral behavior of emissivity of light-emitting particles. Normally, this spectral behavior is considered time-independent. The current paper challenges this assumption and explains why the emissivity of oxide nanoparticles formed in flame can change with time. The suggested phenomenon is related to transitions of electrons between the valence and conduction energy bands in oxides that are wide-gap dielectrics. The emissivity change is particularly crucial for the interpretation of fast processes occurring during laser-induced experiments. In the present work, we compare the response of titania particles produced by a flame spray to the laser irradiation at two different excitation wavelengths. The difference in the temporal behavior of the corresponding light emission intensities is attributed to the different mechanisms of electron excitation during the laser pulse. Interband transitions that are possible only in the case of the laser photon energy exceeding the titania energy gap led to the increase of the electron density in the conduction band. Relaxation of those electrons back to the valence band is the origin of the observed emissivity drop after the UV laser irradiation.

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