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Journal of Perinatology : Official... Jan 2015Randomized controlled trials evaluating low-target oxygen saturation (SpO2:85% to 89%) vs high-target SpO2 (91% to 95%) have shown variable results regarding mortality... (Review)
Review
Randomized controlled trials evaluating low-target oxygen saturation (SpO2:85% to 89%) vs high-target SpO2 (91% to 95%) have shown variable results regarding mortality and morbidity in extremely preterm infants. Because of the variation inherent to the accuracy of pulse oximeters, the unspecified location of probe placement, the intrinsic relationship between SpO2 and arterial oxygen saturation (SaO2) and between SaO2 and partial pressure of oxygen (PaO2) (differences in oxygen dissociation curves for fetal and adult hemoglobin), the two comparison groups could have been more similar than dissimilar. The SpO2 values were in the target range for a shorter period of time than intended due to practical and methodological constraints. So the studies did not truly compare 'target SpO2 ranges'. In spite of this overlap, some of the studies did find significant differences in mortality prior to discharge, necrotizing enterocolitis and severe retinopathy of prematurity. These differences could potentially be secondary to time spent beyond the target range (SpO2 <85 or >95%) and could be avoided with an intermediate but wider target SpO2 range (87% to 93%). In conclusion, significant uncertainty persists about the desired target range of SpO2 in extremely preterm infants. Further studies should focus on studying newer methods of assessing oxygenation and strategies to limit hypoxemia (<85% SpO2) and hyperoxemia (>95% SpO2).
Topics: Humans; Infant, Extremely Low Birth Weight; Infant, Newborn; Oximetry; Oxygen; Oxygen Inhalation Therapy; Randomized Controlled Trials as Topic; Software
PubMed: 25357098
DOI: 10.1038/jp.2014.199 -
Journal of Postgraduate Medicine 2015Obstructive sleep apnea (OSA) is a common but underdiagnosed sleep disorder, which is associated with systemic consequences such as hypertension, stroke, metabolic... (Review)
Review
Obstructive sleep apnea (OSA) is a common but underdiagnosed sleep disorder, which is associated with systemic consequences such as hypertension, stroke, metabolic syndrome, and ischemic heart disease. Nocturnal laboratory-based polysomnography (PSG) is the gold standard test for diagnosis of OSA. PSG consists of a simultaneous recording of multiple physiologic parameters related to sleep and wakefulness including electroencephalography (EEG), electrooculography (EOG), surface electromyography (EMG), airflow measurement using thermistor and nasal pressure transducer, pulse oximetry and respiratory effort (thoracic and abdominal). Multiple alternative and simpler methods that record respiratory parameters alone for diagnosing OSA have been developed in the past two decades. These devices are called portable monitors (PMs) and enable performing sleep studies at a lower cost with shorter waiting times. It has been observed and reported that comprehensive sleep evaluation coupled with the use of PMs can fulfill the unmet need for diagnostic testing in various out-of-hospital settings in patients with suspected OSA. This article reviews the available medical literature on PMs in order to justify the utility of PMs in the diagnosis of OSA, especially in resource-poor, high-disease burden settings. The published practice parameters for the use of these devices have also been reviewed with respect to their relevance in the Indian setting.
Topics: Electroencephalography; Humans; Monitoring, Ambulatory; Oximetry; Polysomnography; Practice Guidelines as Topic; Sleep Apnea, Obstructive
PubMed: 26440391
DOI: 10.4103/0022-3859.166509 -
Noninvasive Non-Contact SpO Monitoring Using an Integrated Polarization-Sensing CMOS Imaging Sensor.Sensors (Basel, Switzerland) Oct 2022In the diagnosis and primary health care of an individual, estimation of the pulse rate and blood oxygen saturation (SpO2) is critical. The pulse rate and SpO2 are...
BACKGROUND
In the diagnosis and primary health care of an individual, estimation of the pulse rate and blood oxygen saturation (SpO2) is critical. The pulse rate and SpO2 are determined by methods including photoplethysmography (iPPG), light spectroscopy, and pulse oximetry. These devices need to be compact, non-contact, and noninvasive for real-time health monitoring. Reflection-based iPPG is becoming popular as it allows non-contact estimation of the heart rate and SpO2. Most iPPG methods capture temporal data and form complex computations, and thus real-time measurements and spatial visualization are difficult.
METHOD
In this research work, reflective mode polarized imaging-based iPPG is proposed. For polarization imaging, a custom image sensor with wire grid polarizers on each pixel is designed. Each pixel has a wire grid of varying transmission axes, allowing phase detection of the incoming light. The phase information of the backscattered light from the fingertips of 12 healthy volunteers was recorded in both the resting as well as the excited states. These data were then processed using MATLAB 2021b software.
RESULTS
The phase information provides quantitative information on the reflection from the superficial and deep layers of skin. The ratio of deep to superficial layer backscattered phase information is shown to be directly correlated and linearly increasing with an increase in the SpO2 and heart rate.
CONCLUSIONS
The phase-based measurements help to monitor the changes in the resting and excited state heart rate and SpO2 in real time. Furthermore, the use of the ratio of phase information helps to make the measurements independent of the individual skin traits and thus increases the accuracy of the measurements. The proposed iPPG works in ambient light, relaxing the instrumentation requirement and helping the system to be compact and portable.
Topics: Humans; Oximetry; Photoplethysmography; Monitoring, Physiologic; Heart Rate; Fingers; Oxygen
PubMed: 36298147
DOI: 10.3390/s22207796 -
The American Journal of Bioethics : AJOB Apr 2023It is well-known that racism is encoded into the social practices and institutions of medicine. Less well-known is that racism is encoded into the material artifacts of...
It is well-known that racism is encoded into the social practices and institutions of medicine. Less well-known is that racism is encoded into the material artifacts of medicine. We argue that many medical devices are not merely biased, but materialize oppression. An oppressive device exhibits a harmful bias that reflects and perpetuates unjust power relations. Using pulse oximeters and spirometers as case studies, we show how medical devices can materialize oppression along various axes of social difference, including race, gender, class, and ability. Our account uses political philosophy and cognitive science to give a theoretical basis for understanding materialized oppression, explaining how artifacts encode and carry oppressive ideas from the past to the present and future. Oppressive medical devices present a moral aggregation problem. To remedy this problem, we suggest redundantly layered solutions that are coordinated to disrupt reciprocal causal connections between the attitudes, practices, and artifacts of oppressive systems.
Topics: Humans; Racism; Biomedical Technology; Oximetry; Spirometry
PubMed: 35262465
DOI: 10.1080/15265161.2022.2044543 -
Current Opinion in Anaesthesiology Dec 2015There is an increasing interest in the application of near-infrared spectroscopy (NIRS) as a monitoring tool in noncardiac surgery. This review summarizes the latest... (Review)
Review
PURPOSE OF REVIEW
There is an increasing interest in the application of near-infrared spectroscopy (NIRS) as a monitoring tool in noncardiac surgery. This review summarizes the latest developments and current evidence for the use of NIRS in the noncardiac intraoperative setting.
RECENT FINDINGS
Unanticipated intraoperative physiological disturbances and a substantial interpatient variability in the limits of cerebral autoregulation, pose our patients at risk for adverse cerebral outcome, if the brain is not monitored specifically. In addition to a means to monitor the brain, NIRS has been shown to allow an estimate of overall organ oxygenation. Preliminary data suggest a relationship between cerebral desaturation and both neurologic and major organ morbidity.
SUMMARY
NIRS offers noninvasive monitoring of cerebral and overall organ oxygenation in a wide range of clinical scenarios. There is an increasing evidence that the optimized cerebral oxygenation is associated with improved outcomes in both neurologic and major organ morbidity in a variety of surgical settings.
Topics: Brain; Cerebrovascular Circulation; Monitoring, Intraoperative; Oximetry; Spectroscopy, Near-Infrared
PubMed: 26418554
DOI: 10.1097/ACO.0000000000000256 -
Sensors (Basel, Switzerland) May 2022The purpose of this research was to develop an algorithm for a wearable device that would prevent people from drowning in swimming pools. The device should detect...
The purpose of this research was to develop an algorithm for a wearable device that would prevent people from drowning in swimming pools. The device should detect pre-drowning symptoms and alert the rescue staff. The proposed detection method is based on analyzing real-time data collected from a set of sensors, including a pulse oximeter. The pulse oximetry technique is used for measuring the heart rate and oxygen saturation in the subject's blood. It is an optical method; subsequently, the measurements obtained this way are highly sensitive to interference from the subject's motion. To eliminate noise caused by the subject's movement, accelerometer data were used in the system. If the acceleration sensor does not detect movement, a biosensor is activated, and an analysis of selected physiological parameters is performed. Such a setup of the algorithm allows the device to distinguish situations in which the person rests and does not move from situations in which the examined person has lost consciousness and has begun to drown.
Topics: Drowning; Humans; Oximetry; Oxygen; Swimming Pools; Wearable Electronic Devices
PubMed: 35632232
DOI: 10.3390/s22103823 -
Archivos Argentinos de Pediatria Apr 2022Near infrared spectroscopy (NIRS) is a non-invasive optical technique for the evaluation of regional tissue oxygenation using transcutaneous detectors. In recent years,... (Review)
Review
Near infrared spectroscopy (NIRS) is a non-invasive optical technique for the evaluation of regional tissue oxygenation using transcutaneous detectors. In recent years, publications about this topic have increased exponentially; this reflects the growing interest among investigators and clinicians about this new technology and its potential benefits for pediatric patients. The objective of this review is to know the functioning and potential uses of regional saturation measured by NIRS and establish future challenges.
Topics: Child; Hemodynamic Monitoring; Humans; Oximetry; Oxygen; Pediatrics; Spectroscopy, Near-Infrared
PubMed: 35338818
DOI: 10.5546/aap.2022.eng.129 -
Critical Reviews in Biomedical... 2019Heart rate and through-body blood perfusion are vital measurements in all stages of patient care, be it predictive, in the clinical setting, or outpatient monitoring....
Heart rate and through-body blood perfusion are vital measurements in all stages of patient care, be it predictive, in the clinical setting, or outpatient monitoring. Irregular, underachieving, or overperforming heart rate is the main precursor of most cardiovascular diseases that have severe long-term complications. In addition to heart rate, the shape of the pulse waveforms can indicate the heart's valve health and electrophysiology health. The goal of the study was to design a noninvasive device for continuously measuring a patient's heart rate with clinical-grade accuracy along with the ability to indicate pulse waveforms for the patient and physician. An accurate, easy-to-use heart-rate measuring device prototype was developed that did not require the sensor to have direct skin contact to obtain measurements. The statistical analysis of the data gathered by the prototype compared to the data collected from the industry standard device indicated significant correlation. The two-sample T-test for the data recorded from the prototype and the data collected from the industry commercially available pulse oximeter showed a P-value of 0.521, which indicates that there was no significant difference between the prototype and the commercially available pulse oximeter when measuring heart rate.
Topics: Alkenes; Calibration; Electrocardiography; Electrophysiological Phenomena; Equipment Design; Ethylenes; Heart Rate; Humans; Linear Models; Materials Testing; Microcomputers; Movement; Oximetry; Oxygen; Perfusion; Reproducibility of Results; Styrene
PubMed: 31679242
DOI: 10.1615/CritRevBiomedEng.2019026539 -
PloS One 2021Retinal oximetry is a technique based on spectrophotometry where images are analyzed with software capable of calculating vessel oxygen saturation and vessel diameter....
PURPOSE
Retinal oximetry is a technique based on spectrophotometry where images are analyzed with software capable of calculating vessel oxygen saturation and vessel diameter. In this study, the effect of automation of measurements of retinal vessel oxygen saturation and vessel diameter is explored.
METHODS
Until now, operators have had to choose each vessel segment to be measured explicitly. A new, automatic version of the software automatically selects the vessels once the operator defines a measurement area. Five operators analyzed image pairs from the right eye of 23 healthy subjects with semiautomated retinal oximetry analysis software, Oxymap Analyzer (v2.5.1), and an automated version (v3.0). Inter- and intra-operator variability was investigated using the intraclass correlation coefficient (ICC) between oxygen saturation measurements of vessel segments in the same area of the retina.
RESULTS
For semiautomated saturation measurements, the inter-rater ICC was 0.80 for arterioles and venules. For automated saturation measurements, the inter-rater ICC was 0.97 for arterioles and 0.96 for venules. For semiautomated diameter measurements, the inter-rater ICC was 0.71 for arterioles and venules. For automated diameter measurements the inter-rater ICC was 0.97 for arterioles and 0.95 for venules. The inter-rater ICCs were different (p < 0.01) between the semiautomated and automated version in all instances.
CONCLUSION
Automated measurements of retinal oximetry values are more repeatable compared to measurements where vessels are selected manually.
Topics: Adult; Automation; Humans; Oximetry; Oxygen; Reproducibility of Results; Retinal Vessels; Software; Venules; Young Adult
PubMed: 34914738
DOI: 10.1371/journal.pone.0260120 -
Sensors (Basel, Switzerland) Nov 2023Obstructive Sleep Apnea (OSA) is a respiratory disorder characterized by frequent breathing pauses during sleep. The apnea-hypopnea index is a measure used to assess the... (Review)
Review
Obstructive Sleep Apnea (OSA) is a respiratory disorder characterized by frequent breathing pauses during sleep. The apnea-hypopnea index is a measure used to assess the severity of sleep apnea and the hourly rate of respiratory events. Despite numerous commercial devices available for apnea diagnosis and early detection, accessibility remains challenging for the general population, leading to lengthy wait times in sleep clinics. Consequently, research on monitoring and predicting OSA has surged. This comprehensive paper reviews devices, emphasizing distinctions among representative apnea devices and technologies for home detection of OSA. The collected articles are analyzed to present a clear discussion. Each article is evaluated according to diagnostic elements, the implemented automation level, and the derived level of evidence and quality rating. The findings indicate that the critical variables for monitoring sleep behavior include oxygen saturation (oximetry), body position, respiratory effort, and respiratory flow. Also, the prevalent trend is the development of level IV devices, measuring one or two signals and supported by prediction software. Noteworthy methods showcasing optimal results involve neural networks, deep learning, and regression modeling, achieving an accuracy of approximately 99%.
Topics: Humans; Polysomnography; Sleep Apnea, Obstructive; Sleep; Sleep Apnea Syndromes; Oximetry
PubMed: 38067885
DOI: 10.3390/s23239512