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Journal of Clinical Monitoring and... Dec 2021In patients at high risk of respiratory complications, pulse oximetry may not adequately detect hypoventilation events. Previous studies have proposed using...
In patients at high risk of respiratory complications, pulse oximetry may not adequately detect hypoventilation events. Previous studies have proposed using thermography, which relies on infrared imaging, to measure respiratory rate (RR). These systems lack support from real-world feasibility testing for widespread acceptance. This study enrolled 101 spontaneously ventilating patients in a post-anesthesia recovery unit. Patients were placed in a 45° reclined position while undergoing pulse oximetry and bioimpedance-based RR monitoring. A thermography camera was placed approximately 1 m from the patient and pointed at the patient's face, recording continuously at 30 frames per second for 2 min. Simultaneously, RR was manually recorded. Offline imaging analysis identified the nares as a region of interest and then quantified nasal temperature changes frame by frame to estimate RR. The manually calculated RR was compared with both bioimpedance and thermographic estimates. The Pearson correlation coefficient between direct measurement and bioimpedance was 0.69 (R = 0.48), and that between direct measurement and thermography was 0.95 (R = 0.90). Limits of agreement analysis revealed a bias of 1.3 and limits of agreement of 10.8 (95% confidence interval 9.07 to 12.5) and - 8.13 (- 6.41 to - 9.84) between direct measurements and bioimpedance, and a bias of -0.139 and limits of agreement of 2.65 (2.14 to 3.15) and - 2.92 (- 2.41 to 3.42) between direct measurements and thermography. Thermography allowed tracking of the manually measured RR in the post-anesthesia recovery unit without requiring patient contact. Additional work is required for image acquisition automation and nostril identification.
Topics: Anesthetics; Humans; Monitoring, Physiologic; Oximetry; Respiratory Rate; Thermography
PubMed: 32975639
DOI: 10.1007/s10877-020-00595-8 -
Journal of Hospital Medicine Jan 2021
Topics: Bronchiolitis; Hospitals; Humans; Oximetry
PubMed: 33357335
DOI: 10.12788/jhm.3563 -
PloS One 2022Neonatal multiparameter continuous physiological monitoring (MCPM) technologies assist with early detection of preventable and treatable causes of neonatal mortality....
BACKGROUND
Neonatal multiparameter continuous physiological monitoring (MCPM) technologies assist with early detection of preventable and treatable causes of neonatal mortality. Evaluating accuracy of novel MCPM technologies is critical for their appropriate use and adoption.
METHODS
We prospectively compared the accuracy of Sibel's Advanced Neonatal Epidermal (ANNE) technology with Masimo's Rad-97 pulse CO-oximeter with capnography and Spengler's Tempo Easy reference technologies during four evaluation rounds. We compared accuracy of heart rate (HR), respiratory rate (RR), oxygen saturation (SpO2), and skin temperature using Bland-Altman plots and root-mean-square deviation analyses (RMSD). Sibel's ANNE algorithms were optimized between each round. We created Clarke error grids with zones of 20% to aid with clinical interpretation of HR and RR results.
RESULTS
Between November 2019 and August 2020 we collected 320 hours of data from 84 neonates. In the final round, Sibel's ANNE technology demonstrated a normalized bias of 0% for HR and 3.1% for RR, and a non-normalized bias of -0.3% for SpO2 and 0.2°C for temperature. The normalized spread between 95% upper and lower limits-of-agreement (LOA) was 4.7% for HR and 29.3% for RR. RMSD for SpO2 was 1.9% and 1.5°C for temperature. Agreement between Sibel's ANNE technology and the reference technologies met the a priori-defined thresholds for 95% spread of LOA and RMSD. Clarke error grids showed that all HR and RR observations were within a 20% difference.
CONCLUSION
Our findings suggest acceptable agreement between Sibel's ANNE and reference technologies. Clinical effectiveness, feasibility, usability, acceptability, and cost-effectiveness investigations are necessary for large-scale implementation.
Topics: Humans; Infant, Newborn; Kenya; Monitoring, Physiologic; Oximetry; Oxygen; Respiratory Rate
PubMed: 35771801
DOI: 10.1371/journal.pone.0267026 -
BMC Health Services Research Nov 2022Pulse oximetry monitoring is included in the WHO Safe Surgery Checklist and recognized as an essential perioperative safety monitoring device. However, many low resource...
BACKGROUND
Pulse oximetry monitoring is included in the WHO Safe Surgery Checklist and recognized as an essential perioperative safety monitoring device. However, many low resource countries do not have adequate numbers of pulse oximeters available or healthcare workers trained in their use. Lifebox, a nonprofit organization focused on improving anesthetic and surgical safety, has procured and distributed pulse oximeters and relevant educational training in over 100 countries. We aimed to understand qualitatively how pulse oximetry provision and training affected a group of Zambian non-physician anesthetists' perioperative care and what, if any, capacity gaps remain.
METHODS
We identified and approached non-physician anesthetists (NPAPs) in Zambia who attended a 2019 Lifebox pulse oximetry training course to participate in a semi-structured interview. Interviews were audio recorded and transcribed. Codes were iteratively derived; the codebook was tested for inter-rater reliability (pooled kappa > 0.70). Team-based thematic analysis identified emergent themes on pulse oximetry training and perioperative patient care.
RESULTS
Ten of the 35 attendees were interviewed. Two themes emerged concerning pulse oximetry provision and training in discussion with non-physician anesthetists about their experience after training: (1) Impact on Non-Physician Anesthetists and the Healthcare Team and (2) Impact on Perioperative Patient Monitoring. These broad themes were further explored through subthemes. Increased knowledge brought confidence in monitoring and facilitated quick interventions. NPAPs reported improved preoperative assessments and reaffirmed the necessity of having pulse oximetry intraoperatively. However, lack of device availability led to case delays or cancellations. A portable device travelling with the patient to the recovery ward was noted as a major improvement in postoperative care. Pulse oximeters also improved communication between nurses and NPAPs, giving NPAPs confidence in the recovery process. However, this was not always possible, as lack of pulse oximeters and ward staff unfamiliarity with oximetry was commonly reported. NPAPs expressed that wider pulse oximetry availability and training would be beneficial.
CONCLUSION
Among a cohort of non-physician anesthetists in Zambia, the provision of pulse oximeters and training was perceived to improve patient care throughout the perioperative timeline. However, capacity and resource gaps remain in their practice settings, especially during transfers of care. NPAPs identified a number of areas where patient care and safety could be improved, including expanding access to pulse oximetry training and provision to ward and nursing staff to ensure the entire healthcare team is aware of the benefits and importance of its use.
Topics: Humans; Zambia; Reproducibility of Results; Oximetry; Oxygen; Anesthesiologists; Perioperative Care
PubMed: 36419106
DOI: 10.1186/s12913-022-08698-5 -
Journal of Otolaryngology - Head & Neck... Dec 2019Obstructive sleep apnea (OSA) is the most common indication for adenotonsillectomy in children. Home-based sleep oximetry continues to be used in the diagnosis of...
BACKGROUND
Obstructive sleep apnea (OSA) is the most common indication for adenotonsillectomy in children. Home-based sleep oximetry continues to be used in the diagnosis of pediatric OSA despite a lack of correlation with lab-based polysomnography. This study investigates whether factors influence surgeons in selecting patients for home-based sleep oximetry, how the study findings are used in patient management, and whether abnormal oximetry findings are associated with post-operative complications.
METHODS
A retrospective review was performed on children with suspected OSA who had undergone a tonsillectomy and/or an adenoidectomy over a three-year period. Demographic features, comorbidities, pre-operative oximetry results, and post-operative complications were recorded. Data analysis consisting primarily of logistic regression was performed using Stata 12.0 (College Station, Texas).
RESULTS
Data was collected from 389 children. Two hundred and seventy-one children underwent pre-operative oximetry (69.7%). There was no significant association between age or the presence of comorbidities and the likelihood of undergoing pre-operative sleep oximetry. The post-operative complication rate was 0.8%. There was no significant association between abnormal sleep oximetry parameters and post-operative complications. Children with one or more abnormal sleep oximetry parameters were more likely to be observed in hospital for at least one night (OR 2.4, p < 0.0001).
CONCLUSIONS
Our study suggests that surgeons are using home-based sleep oximetry findings to inform the post-operative care of children with suspected OSA, as those with abnormal home-based sleep oximetry findings were more likely to be observed in hospital. These hospital admissions may be unnecessary given the poor correlation of home-based oximetry and PSG as well as the low rate of serious post-operative complications.
Topics: Adenoidectomy; Adolescent; Child; Child, Preschool; Female; Humans; Infant; Male; Oximetry; Polysomnography; Preoperative Period; Reproducibility of Results; Retrospective Studies; Sleep Apnea, Obstructive; Tonsillectomy
PubMed: 31796111
DOI: 10.1186/s40463-019-0391-2 -
Journal of the American Heart... Jun 2024Oxygen saturation (Spo) screening has not led to earlier detection of critical congenital heart disease (CCHD). Adding pulse oximetry features (ie, perfusion data and...
BACKGROUND
Oxygen saturation (Spo) screening has not led to earlier detection of critical congenital heart disease (CCHD). Adding pulse oximetry features (ie, perfusion data and radiofemoral pulse delay) may improve CCHD detection, especially coarctation of the aorta (CoA). We developed and tested a machine learning (ML) pulse oximetry algorithm to enhance CCHD detection.
METHODS AND RESULTS
Six sites prospectively enrolled newborns with and without CCHD and recorded simultaneous pre- and postductal pulse oximetry. We focused on models at 1 versus 2 time points and with/without pulse delay for our ML algorithms. The sensitivity, specificity, and area under the receiver operating characteristic curve were compared between the Spo-alone and ML algorithms. A total of 523 newborns were enrolled (no CHD, 317; CHD, 74; CCHD, 132, of whom 21 had isolated CoA). When applying the Spo-alone algorithm to all patients, 26.2% of CCHD would be missed. We narrowed the sample to patients with both 2 time point measurements and pulse-delay data (no CHD, 65; CCHD, 14) to compare ML performance. Among these patients, sensitivity for CCHD detection increased with both the addition of pulse delay and a second time point. All ML models had 100% specificity. With a 2-time-points+pulse-delay model, CCHD sensitivity increased to 92.86% (=0.25) compared with Spo alone (71.43%), and CoA increased to 66.67% (=0.5) from 0. The area under the receiver operating characteristic curve for CCHD and CoA detection significantly improved (0.96 versus 0.83 for CCHD, 0.83 versus 0.48 for CoA; both =0.03) using the 2-time-points+pulse-delay model compared with Spo alone.
CONCLUSIONS
ML pulse oximetry that combines oxygenation, perfusion data, and pulse delay at 2 time points may improve detection of CCHD and CoA within 48 hours after birth.
REGISTRATION
URL: https://www.clinicaltrials.gov/study/NCT04056104?term=NCT04056104&rank=1; Unique identifier: NCT04056104.
Topics: Humans; Oximetry; Heart Defects, Congenital; Infant, Newborn; Male; Female; Neonatal Screening; Machine Learning; Prospective Studies; Oxygen Saturation; Predictive Value of Tests; Algorithms; ROC Curve
PubMed: 38879455
DOI: 10.1161/JAHA.123.033786 -
PloS One 2020Retinal oximetry is an important screening tool for early detection of retinal pathologies due to changes in the vasculature and also serves as a useful indicator of...
Retinal oximetry is an important screening tool for early detection of retinal pathologies due to changes in the vasculature and also serves as a useful indicator of human-body-wide vascular abnormalities. We present an automatic technique for the measurement of oxygen saturation in retinal arterioles and venules using dual-wavelength retinal oximetry images. The technique is based on segmenting an optic-disc-centered ring-shaped region of interest and subsequent analysis of the oxygen saturation levels. We show that the two dominant peaks in the histogram of the oxygen saturation levels correspond to arteriolar and venular oxygen saturations from which the arterio-venous saturation difference (AVSD) can be calculated. For evaluation, we use a normative database of Asian Indian eyes containing 44 dual-wavelength retinal oximetry images. Validations against expert manual annotations of arterioles and venules show that the proposed technique results in an average arteriolar oxygen saturation (SatO2) of 87.48%, venular SatO2 of 57.41%, and AVSD of 30.07% in comparison with the expert ground-truth average arteriolar SatO2 of 89.41%, venular SatO2 of 56.32%, and AVSD of 33.09%, respectively. The results exhibit high consistency across the dataset indicating that the automated technique is an accurate alternative to the manual procedure.
Topics: Arterioles; Female; Humans; Male; Oximetry; Oxygen; Oxygen Consumption; Retina; Retinal Vessels; Venules
PubMed: 32421691
DOI: 10.1371/journal.pone.0231677 -
Journal of Magnetic Resonance (San... Jul 2021Electron paramagnetic resonance (EPR) oximetry, using oxygen-sensing implant such as OxyChip, is capable of measuring oxygen concentration in vivo - a critical tissue...
Electron paramagnetic resonance (EPR) oximetry, using oxygen-sensing implant such as OxyChip, is capable of measuring oxygen concentration in vivo - a critical tissue information required for successful medical treatment such as cancer, wound healing and diabetes. Typically, EPR oximetry produces one value of the oxygen concentration, expressed as pO at the site of implant. However, it is well recognized that in vivo one deals with a distribution of oxygen concentration and therefore reporting just one number is not representative_a long-standing critique of EPR oximetry. Indeed, when it comes to the assessment of radiation efficacy one should be guided not by the mean or median but the proportion of oxygenated cancer cells which can be estimated only when the whole oxygen distribution in the tumor is known. Although there is a handful of papers attempting estimation of the oxygen distribution they suffer from the problem of negative frequencies and no theoretical justification and no biomedical interpretation. The goal of this work is to suggest a novel method using the empirical Bayesian approach realized via nonlinear mixed modeling with a priori distribution of oxygen following a two-parameter lognormal distribution with parameters estimated from the multi-implant single component EPR scan. Unlike previous work, the result of our estimation is the distribution with positive values for the frequency and the associated pO value. Our algorithm based on nonlinear regression is illustrated with EPR measurements on OxyChips equilibrated with gas mixtures containing four values of pO and computation of the proportion of volume with pO greater than any given threshold. This approach may become crucial for application of the EPR oximetry in clinical setting when the sucsess of the treatment depends of the proportion of tissue oxygenated.
Topics: Bayes Theorem; Electron Spin Resonance Spectroscopy; Humans; Neoplasms; Oximetry; Oxygen
PubMed: 33965648
DOI: 10.1016/j.jmr.2021.106992 -
Sensors (Basel, Switzerland) Feb 2023The early identification of microvascular changes in patients with Coronavirus Disease 2019 (COVID-19) may offer an important clinical opportunity. This study aimed to...
The early identification of microvascular changes in patients with Coronavirus Disease 2019 (COVID-19) may offer an important clinical opportunity. This study aimed to define a method, based on deep learning approaches, for the identification of COVID-19 patients from the analysis of the raw PPG signal, acquired with a pulse oximeter. To develop the method, we acquired the PPG signal of 93 COVID-19 patients and 90 healthy control subjects using a finger pulse oximeter. To select the good quality portions of the signal, we developed a template-matching method that excludes samples corrupted by noise or motion artefacts. These samples were subsequently used to develop a custom convolutional neural network model. The model accepts PPG signal segments as input and performs a binary classification between COVID-19 and control samples. The proposed model showed good performance in identifying COVID-19 patients, achieving 83.86% accuracy and 84.30% sensitivity (hold-out validation) on test data. The obtained results indicate that photoplethysmography may be a useful tool for microcirculation assessment and early recognition of SARS-CoV-2-induced microvascular changes. In addition, such a noninvasive and low-cost method is well suited for the development of a user-friendly system, potentially applicable even in resource-limited healthcare settings.
Topics: Humans; Photoplethysmography; COVID-19; SARS-CoV-2; Oximetry; Oxygen; Neural Networks, Computer; Signal Processing, Computer-Assisted; Heart Rate
PubMed: 36904763
DOI: 10.3390/s23052561 -
Anaesthesia Feb 2022
Topics: Humans; Oximetry; Oxygen; Racial Groups
PubMed: 34844284
DOI: 10.1111/anae.15635