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Sensors (Basel, Switzerland) Jun 2022Current methods of measuring heart rate (HR) and oxygen levels (SPO2) require physical contact, are individualised, and for accurate oxygen levels may also require a...
Current methods of measuring heart rate (HR) and oxygen levels (SPO2) require physical contact, are individualised, and for accurate oxygen levels may also require a blood test. No-touch or non-invasive technologies are not currently commercially available for use in healthcare settings. To date, there has been no assessment of a system that measures HR and SPO2 using commercial off-the-shelf camera technology that utilises R, G, B, and IR data. Moreover, no formal remote photoplethysmography studies have been performed in real-life scenarios with participants at home with different demographic characteristics. This novel study addresses all these objectives by developing, optimising, and evaluating a system that measures the HR and SPO2 of 40 participants. HR and SPO2 are determined by measuring the frequencies from different wavelength band regions using FFT and radiometric measurements after pre-processing face regions of interest (forehead, lips, and cheeks) from colour, IR, and depth data. Detrending, interpolating, hamming, and normalising the signal with FastICA produced the lowest RMSE of 7.8 for HR with the r-correlation value of 0.85 and RMSE 2.3 for SPO2. This novel system could be used in several critical care settings, including in care homes and in hospitals and prompt clinical intervention as required.
Topics: Face; Forehead; Humans; Oximetry; Oxygen; Photoplethysmography
PubMed: 35808469
DOI: 10.3390/s22134974 -
Advances in Experimental Medicine and... 2014EPR oximetry, which enables reliable, accurate, and repeated measurements of the partial pressure of oxygen in tissues, provides a unique opportunity to investigate the... (Review)
Review
EPR oximetry, which enables reliable, accurate, and repeated measurements of the partial pressure of oxygen in tissues, provides a unique opportunity to investigate the role of oxygen in the pathogenesis and treatment of several diseases including cancer, stroke, and heart failure. Building on significant advances in the in vivo application of EPR oximetry for small animal models of disease, we are developing suitable probes and instrumentation required for use in human subjects. Our laboratory has established the feasibility of clinical EPR oximetry in cancer patients using India ink, the only material presently approved for clinical use. We now are developing the next generation of probes, which are both superior in terms of oxygen sensitivity and biocompatibility including an excellent safety profile for use in humans. Further advances include the development of implantable oxygen sensors linked to an external coupling loop for measurements of deep-tissue oxygenations at any depth, overcoming the current limitation of 10 mm. This paper presents an overview of recent developments in our ability to make meaningful measurements of oxygen partial pressures in human subjects under clinical settings.
Topics: Animals; Electron Spin Resonance Spectroscopy; Models, Animal; Oximetry; Spin Labels
PubMed: 24729217
DOI: 10.1007/978-1-4939-0620-8_10 -
Anaesthesia Jan 2017Monitors using near-infra red spectroscopy to assess cerebral oxygenation levels non-invasively in discrete areas of the brain have been used clinically for over... (Review)
Review
Monitors using near-infra red spectroscopy to assess cerebral oxygenation levels non-invasively in discrete areas of the brain have been used clinically for over 20 years. Interest has intensified recently, especially during cardiac surgery, and there are now five commercially available devices. Despite the attraction of being able to measure oxygen supply/demand in such a critical area, there has been only limited uptake of this technology in overall clinical anaesthetic practice. This narrative review aims to explore not only the rationale for using this technology but also the factors which have restricted its more widespread use.
Topics: Adult; Brain; Cardiac Surgical Procedures; Cardiopulmonary Resuscitation; Humans; Oximetry; Oxygen
PubMed: 28044331
DOI: 10.1111/anae.13740 -
Pediatric Critical Care Medicine : a... Jun 2023Pulse oximetry (Sp o2 ) may overestimate arterial oxygen saturation (Sa o2 ) in blood laboratory testing. This study aimed to assess Sp o2 -Sa o2 difference in relation...
OBJECTIVES
Pulse oximetry (Sp o2 ) may overestimate arterial oxygen saturation (Sa o2 ) in blood laboratory testing. This study aimed to assess Sp o2 -Sa o2 difference in relation to race (i.e., patient self-reporting as Black or White), occult hypoxemia, and length of stay (LOS) in pediatric patients with COVID-19.
DESIGN
Single-center retrospective study in pediatric COVID-19 patients. We used multivariable linear regressions to examine the association between race and oximetry measurements and between occult hypoxemia and LOS. Oximetry bias was defined using Sp o2 and Sa o2 data according to approved comparisons. Occult hypoxemia was defined as Sp o2 greater than 92% and Sa o2 less than 88%.
SETTING
Quaternary pediatric hospital.
PATIENTS
Pediatric COVID-19 patients admitted to Texas Children's Hospital between May 2020 and December 2021.
INTERVENTIONS
None.
MEASUREMENTS AND MAIN RESULTS
There were 2713 patients with complete physiological data in the analysis. Of the total, 61% were Black, and 39% were White. Oximetry bias was greater in Black compared with White patients ( p < 0.001), and this bias increased as the oxygen saturations decreased ( p < 0.001). Black and White patients had a 12% and 4% prevalence of occult hypoxemia, respectively ( p < 0.001). LOS was not associated with oximetry bias or occult hypoxemia once controlled for the level of support (intensive care, respiratory, circulatory).
CONCLUSIONS
We found an oximetry bias in the measurement of Sp o2 with respect to Sa o2 in symptomatic hospitalized pediatric patients with the diagnosis of COVID-19. Furthermore, race is related to an increased oximetry bias. However, we did not find a relationship between oximetry bias and the LOS in the hospital in this cohort of patients.
Topics: Humans; Child; Retrospective Studies; Oxygen; COVID-19; Oximetry; Hypoxia
PubMed: 36825900
DOI: 10.1097/PCC.0000000000003208 -
Journal of the American Veterinary... Nov 2022To evaluate the accuracy for 2 smartwatches with oximetry technology and optical wrist heart rate (HR) or single-lead Electrocardiography (ECG) technology (Fenix 5X Plus...
Two different smartwatches exhibit high accuracy in evaluating heart rate and peripheral oxygen saturation in cats when compared with the electrocardiography and transmittance pulse oximetry.
OBJECTIVE
To evaluate the accuracy for 2 smartwatches with oximetry technology and optical wrist heart rate (HR) or single-lead Electrocardiography (ECG) technology (Fenix 5X Plus [GF5xp], Garmin Ltd and Apple Watch 6 [AppW6], Apple Inc, respectively) versus reference methods (ECG and transmittance pulse oximetry [TPO], respectively) in measuring HR and peripheral oxygen saturation of hemoglobin (SpO2) in cats.
ANIMALS
10 male client-owned cats aged 8 to 12 months and weighing 3.2 to 4.5 kg.
PROCEDURES
All cats that were presented for elective castration at the Atatürk University Animal Hospital between March 10 and April 15, 2022, were considered for enrollment. Monitoring of HR and SpO2 during anesthesia was performed with a 3-lead ECG and transmittance pulse oximetry, respectively, connected to a multiparameter monitor (reference methods) along with a GF5xp and a AppW6. Agreement between reference methods and the smartwatches were assessed by the Bland-Altman plot, in which the differences (%) between methods were plotted against their mean HR or SpO2 (reference method measurement - test device measurement) and the limits of agreement (mean ± 1.96 × SD).
RESULTS
Compared with ECG measurements of HR, GF5xp had superior bias (-0.1%) and limit of agreement (LoA, 3.0 to -3.3%) versus those of the AppW6 (bias, 0.2%; LoA, 3.7 to -3.4%). Compared with TPO measurements of SpO2, AppW6 had superior bias (0.2%) and LoA (3.0% and -2.5%) versus those of the GF5xp (bias, -2.1%; LoA, 0.2 to -4.4%).
CLINICAL RELEVANCE
Results indicated that the GF5xp and AppW6 exhibited high accuracy in evaluating HR and SpO2 in cats when compared with the reference methods. However, it should be noted that these comparisons were made in anesthetized patients without any systemic disease.
Topics: Male; Cats; Animals; Oxygen Saturation; Oxygen; Heart Rate; Oximetry; Electrocardiography
PubMed: 36322488
DOI: 10.2460/javma.22.08.0357 -
Journal of Biomedical Optics Dec 2023The assessment of biomarkers in the eye is rapidly gaining traction for the screening, diagnosis, and monitoring of ocular and neurological diseases. Targeted ocular...
SIGNIFICANCE
The assessment of biomarkers in the eye is rapidly gaining traction for the screening, diagnosis, and monitoring of ocular and neurological diseases. Targeted ocular spectroscopy is a technology that enables concurrent imaging of the eye fundus and analysis of high-quality spectra from a targeted region within the imaged area. This provides structural, compositional, and functional information of specific regions of the eye fundus from a non-invasive approach to ocular biomarker detection.
AIM
The aim of our study was to demonstrate the multimodal functionality and validation of targeted ocular spectroscopy. This was done , using a reference target and a model eye, and .
APPROACH
Images and spectra from different regions of a reference target and a model eye were acquired and analyzed to validate the system. Targeted ocular fluorescence spectroscopy was also demonstrated with the same model. Subsequently, imaging and diffuse reflectance spectra were acquired to assess blood oxygen saturation in the optic nerve head and the parafovea of healthy subjects.
RESULTS
Tests conducted with the reference target showed accurate spectral analysis within specific areas of the imaging space. In the model eye, distinct spectral signatures were observed for the optic disc, blood vessels, the retina, and the macula, consistent with the variations in tissue composition and functions between these regions. An ocular oximetry algorithm was applied to spectra from the optic nerve head and parafovea of healthy patients, showing significant differences in blood oxygen saturation. Finally, targeted fluorescence spectral analysis was performed .
CONCLUSIONS
Diffuse reflectance and fluorescence spectroscopy in specific regions of the eye fundus open the door to a whole new range of monitoring and diagnostic capabilities, from assessment of oxygenation in glaucoma and diabetic retinopathy to photo-oxidation and photodegradation in age-related macular degeneration.
Topics: Humans; Fundus Oculi; Retina; Optic Disk; Oximetry; Spectrometry, Fluorescence
PubMed: 38111476
DOI: 10.1117/1.JBO.28.12.126004 -
Anesthesiology Jan 1989
Review
Topics: Anesthesiology; Humans; Oximetry; United States
PubMed: 2643368
DOI: 10.1097/00000542-198901000-00019 -
Journal of Plastic, Reconstructive &... Sep 2022Prompt diagnosis and intervention are essential for acute limb ischaemia after trauma. Guidelines for diagnosis are changing with new evidence. Pulse oximetry may be a...
Prompt diagnosis and intervention are essential for acute limb ischaemia after trauma. Guidelines for diagnosis are changing with new evidence. Pulse oximetry may be a useful adjunct. We aim to assess the value of pulse oximetry and other common tests for diagnosing vascular injury. Electronic medical records of patients with limb injuries were identified. Patient demographics, the mechanism of injury, comorbidities, the results of diagnostic tests or examinations, and the end outcome were extracted. Receiver Operator Characteristics (ROC) curves were used to calculate cut-offs with optimum sensitivity and specificity for pulse oximetry. Performance characteristics to predict vascular injury for all documented tests were calculated and compared. SpO2 values were significantly different in the group with and without vascular disruption (p = 0.034). Using a cut-off of 96% calculated from ROC curve analysis, SpO had a sensitivity of 78% and a specificity of 90%. For the other techniques, abnormal pulse oximetry waveform, absent distal pulses, and capillary refill over 2 s were significantly different between the two groups. Abnormal pulse oximetry waveform had the highest specificity (100%) while SpO2 was the most sensitive (78%). We suggest that pulse oximetry is a useful adjunct for patients with limb trauma, an abnormal waveform or SpO2 value below 96% suggests vascular disruption is present. Capillary refill over 2 s and absent distal pulses can also be used; if either are positive, this suggests vascular disruption. No test or examination was shown to be able to exclude vascular injury.
Topics: Humans; Ischemia; Oximetry; Oxygen; Peripheral Vascular Diseases; Sensitivity and Specificity; Vascular System Injuries
PubMed: 35787992
DOI: 10.1016/j.bjps.2022.04.080 -
Physiological Reviews Jan 1960
Topics: Oximetry
PubMed: 14427276
DOI: 10.1152/physrev.1960.40.1.1 -
Anaesthesia May 2013
Topics: Female; Hemoglobinometry; Humans; Oximetry; Pregnancy
PubMed: 23573860
DOI: 10.1111/anae.12246